CDMA Network Planning and Optimization Training Guide for Po

ACDMA-311-C1

CDMA Network Planning

Course Objective:

Familiar with network planning flow and main steps

Master the meaning and values of different parameters in link

budget

Master the principle of CDMA capacity and coverage

Master the principle and method of repeater planning

Master PN planning and initial neighbouring cell planning

method

Contents

1 Wireless Network Planning Process......................................................................................................1-1

1.1 Brief Introduction to Overall Process...............................................................................................1-1

1.2 Network planning Flow....................................................................................................................1-1

2 Coverage Planning of CDMA System...................................................................................................2-1

2.1 Link budget introduction..................................................................................................................2-1

2.2 Differences between CDMA 1x and EV-DO Link Budget...............................................................2-5

3 CDMA Capacity Planning......................................................................................................................3-1

3.1 Prediction of the user quantity..........................................................................................................3-1

3.1.1 Principle of user prediction.....................................................................................................3-1

3.1.2 The method to predict user quantity.......................................................................................3-2

3.2 Service Model...................................................................................................................................3-4

3.2.1 Voice Service Model...............................................................................................................3-4

3.2.2 Data Service Model................................................................................................................3-4

3.3 Capacity calculation of CDMA2000 1X system.............................................................................3-10

3.3.1 The ultimate capacity of isolated BTS..................................................................................3-10

3.3.2 BS capacity in cellar system.................................................................................................3-12

3.4 EV-DO capacity planning...............................................................................................................3-13

3.4.1 Active Subscribers Quantity per Sector................................................................................3-14

3.4.2 Recommended Sector Throughput.......................................................................................3-14

3.4.3 Analysis on Sector Reverse Throughput...............................................................................3-14

3.4.4 Sector forward throughput....................................................................................................3-16

3.4.5 Simplified EV-DO Data Traffic Model.................................................................................3-19

3.5 Planning case..................................................................................................................................3-22

3.5.1 Coverage object....................................................................................................................3-22

3.5.2 Project requirements.............................................................................................................3-24

3.5.3 Link budget...........................................................................................................................3-24

3.5.4 Capacity requirement............................................................................................................3-25

3.5.5 Solution.................................................................................................................................3-26

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4 Site Survey and Planning.......................................................................................................................4-1

4.1 Overview..........................................................................................................................................4-1

4.2 Introduction of site survey................................................................................................................4-1

4.3 Site Selecting Principles...................................................................................................................4-2

4.3.1 No Obvious Barrier Directly Opposite Sector........................................................................4-3

4.3.2 Requirement for Site Height...................................................................................................4-4

4.3.3 Avoiding Mutual Interference with Other Systems.................................................................4-5

4.4 Planned sites survey and selection....................................................................................................4-6

4.4.1 No Serious Obstruction in front of a Site................................................................................4-7

4.4.2 Requirements of site height....................................................................................................4-7

4.4.3 Distance requirement of candidate sites and planned sites.....................................................4-7

4.5 Planning Ultra-far Coverage BS.......................................................................................................4-7

4.6 Marks correspond to different sites...................................................................................................4-8

5 Repeater Planning...................................................................................................................................5-1

5.1 Overview of Repeater.......................................................................................................................5-1

5.2 Repeater Networking and Planning..................................................................................................5-3

5.2.1 Features of Repeater Networking...........................................................................................5-4

5.2.2 Analysis of Noise Introduced by Repeaters............................................................................5-5

5.2.3 The Case that Several Repeaters Share One Donor Base Station.........................................5-11

5.2.4 Repeater Cascading..............................................................................................................5-12

5.2.5 Donor Link of Repeater........................................................................................................5-14

5.2.6 Antenna Feeder System........................................................................................................5-16

5.2.7 Isolation................................................................................................................................5-19

6 Principles for PN Planning and Setting of Initial Neighboringing Cell..............................................6-1

6.1 Overview..........................................................................................................................................6-1

6.2 PN Planning......................................................................................................................................6-2

6.2.1 PILOT_INC setting................................................................................................................6-2

6.2.2 Site PN planning.....................................................................................................................6-4

6.3 Setting of Initial Neighboringing Cell List.......................................................................................6-5

6.4 Setting of Dual Frequency Neighboringing Cells.............................................................................6-7

6.5 PN planning by use of CNO.............................................................................................................6-9

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6.5.1 Parameters Setting of PN Planning.......................................................................................6-10

6.5.2 Setting PN-reusing BTSs......................................................................................................6-13

6.5.3 Querying PN Reuse and PN Offset Information...................................................................6-15

6.5.4 PN Planning..........................................................................................................................6-19

6.5.5 Checking-up PN Reuse.........................................................................................................6-22

6.5.6 Selection of BTSs to be PN Planned.....................................................................................6-23

6.5.7 PN Planning of Capacity-expanded BTS..............................................................................6-24

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Figures

Figure 1-1 Status of network planning in whole project........................................................................1-1

Figure 1-2 Network planning process....................................................................................................1-2

Figure 2-1 Fading Margin——Probability Distribution Function.........................................................2-3

Figure 2-2 Fading Margin——Probability Density Function................................................................2-4

Figure 2-3 Edge Coverage Probability and Area Coverage Probability................................................2-4

Figure 3-1 Graph of time and communication prevalence rate..............................................................3-2

Figure 3-2 call process...........................................................................................................................3-4

Figure 3-3 Setup Procedure of Data Service..........................................................................................3-7

Figure 3-4 Flow Chart of Forward Scheduling Algorithm..................................................................3-18

Figure 3-5 Session in the Data Service................................................................................................3-20

Figure 3-6 Coverage area and key covered areas in H district............................................................3-24

Figure 4-1 Position of site survey in network planning.........................................................................4-1

Figure 5-1 Coverage of repeater............................................................................................................5-2

Figure 5-2 Relation between NIM and thermal noise level rise caused by repeater..............................5-7

Figure 5-3 Equivalent cascaded amplifier.............................................................................................5-8

Figure 5-4 Repeater cascading noise coefficient...................................................................................5-9

Figure 5-5 Multiple access interference...............................................................................................5-10

Figure 5-6 Equivalent model of repeater cascading.............................................................................5-13

Figure 5-7 Free space propagation.......................................................................................................5-14

Figure 5-14 Installation of repeater antennas.......................................................................................5-21

Figure 5-15 Isolation-measuring equipment........................................................................................5-24

Figure 6-1 Position of radio parameter setting in network planning......................................................6-1

Figure 6-2 Example for setting neighboringing cell list........................................................................6-6

Figure 6-3 Interface of PN Planning....................................................................................................6-10

Figure 6-4 Parameters Setting of PN Planning....................................................................................6-11

Figure 6-5 PN Grouping And Reservation..........................................................................................6-13

Figure 6-6 The Setting of PN-reusing BTS.........................................................................................6-14

Figure 6-7 The Deletion of PN-reusing BTS.......................................................................................6-14

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Figure 6-8 Interface of PN Querying...................................................................................................6-15

Figure 6-9 The Distance between PN-reusing Cells............................................................................6-16

Figure 6-10 The Query of PN Reuse Information after PN Planning..................................................6-17

Figure 6-11 The Query of PN Confusion.............................................................................................6-18

Figure 6-12 Manual PN Planning........................................................................................................6-20

Figure 6-13 PN Planning Result..........................................................................................................6-20

Figure 6-14 Auto PN Planning Scheme...............................................................................................6-22

Figure 6-15 The Result of PN Reuse Check-up...................................................................................6-23

Figure 6-16 The Selection of BTSs to be PN Planned.........................................................................6-24

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Tables

Table 2-1 Soft Handoff Gain.................................................................................................................2-5

Table 2-2 Link Budget Differences between CDMA 1x and EV-DO....................................................2-5

Table 2-3 Reverse Link Budget of CDMA2000 1X 800M System.......................................................2-8

Table 2-4 cdma2000 HRPD system 800M forward link budget............................................................2-9

Table 2-5 cdma2000 HRPD system 800M reverse link budget...........................................................2-11

Table 3-1 High-end subscriber distribution...........................................................................................3-7

Table 3-2 Statistics of High-end Subscribers’ Behavior on Data Service..............................................3-8

Table 3-3 Statistics of Low-end Subscribers’ Behavior on Data Service...............................................3-8

Table 3-4 Traffic model in busy hour....................................................................................................3-9

Table 3-5 Capacity requirement calculation for 50,000 subscribers’ exchange.....................................3-9

Table 3-6 Reverse Throughput Calculation of single Sector...............................................................3-15

Table 3-7 Reverse Throughput Calculation of Cellular Sector............................................................3-16

Table 3-8 A Simplified Data Traffic Model of EV-DO........................................................................3-21

Table 3-9 Reverse link budget result...................................................................................................3-25

Table 3-10 Names of access points and the number of allocated telephone in Henggang Branch Bureau

..............................................................................................................................................................3-26

Table 3-11 Solution to coverage..........................................................................................................3-26

Table 4-1 Marks correspond to different sites.......................................................................................4-8

Table 5-1 Example of calculating path loss.........................................................................................5-15

Table 5-2 Repeater feeder....................................................................................................................5-17

Table 5-3 Relation between distance and path loss..............................................................................5-18

Table 5-4 Relation between antenna distance and space propagation loss..........................................5-22

Table 6-1 PILOT_INC typical setting...................................................................................................6-3

Table 6-2 Example for setting neighboringing cell list..........................................................................6-6

Table 6-3 Toolbar of PN Planning.......................................................................................................6-10

Table 6-4 PN grouping scheme 1.........................................................................................................6-12

Table 6-5 PN grouping scheme 2.........................................................................................................6-12

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一 Wireless Network Planning Process

Keypoint

Master the overall process about network planning and the detailed descriptions to

each step.

一.1 Brief Introduction to Overall Process

Network process is committee the basis of the entire wireless network building project.

Its position in the project is shown in Figure 1-1.

Figure 1-1 Status of network planning in whole project

一.2 Network planning Flow

Complete network planning consists of the following stages:

1

Figure 1-2 Network planning process

Figure 1-2 shows the whole procedures of network planning; the following is the rough

definition of each stage.

1. In practical project implementation, some unnecessary stages will be eliminated

in the procedures downsizing stage in accordance with the customer’s

requirement (network planning agreement or other accord) and the actual

conditions of the planned area;

2. Requirement analysis: First, the customer’s needs, which are the basis of the

entire network building, should be understood completely; if the information

about customer’s needs is incorrect, all subsequent work will be futile, and the

result of network planning will not be accepted by the customer; the

requirements can be gotten from various ways, such as communicating with the

customer formally or informally, practical survey (includes planning area

environment survey and available sites survey), the result must be confirmed by

the customer;

3. Available sites survey: this stage includes the following steps: collect the

information of the radio propagation environment in the planning areas; select

suitable sites for field test in radio environment test stage; collect the

information of available sites, in which, suitable sites can be used as the basic

of network topology design;

4. Procedures simplification: After the customer requirements are decided, the

entire process will be simplified in accordance with the actual conditions of the

2

1 Wireless Network Planning Process

project and customer requirements and some unnecessary stages will be

eliminated; for example, a newly created network obviously needs no network

evaluation; or, if the customer is certain that the spectrum is clear, there will be

no need for spectrum scanning; or if the customer makes sure that they can

provide the model for the relating environment or the on-site survey concludes

that the existing model can be applied for the environment of the planned area,

there will be no need for field test and model correction;

5. Plan establishment: establish the work plan in accordance with the simplified

process, project scale, topographical conditions, etc. and the time demand

raised by the customer, gross time setting for each stage (setting the

milestones), need for resources and personnel etc; the large-scale and urgent

task may be done in groups. In this case, information of the groups should be

provided; and the resources and personnel requirement must be confirmed by

project implement unit; then confirm the time schedule with the customer; the

work must be done after the plan had be confirmed;

6. Existing network evaluation: If the status of the expanded or relocated network

is not very clear because, for example, it was not optimized since a long time

ago, generally the wireless network evaluation subproject should be

implemented to learn the current status of the network, to provide information

reference for network planning stage;

7. Radio environment test: includes spectrum scan and field test. They are both

optional.

(1) The purpose of spectrum scan is to learn the spectrum occupation situation in

the network planning area.

(2) There is no need to do spectrum scan in such situations: there is no interference

according to the available information; If the customer does not require

spectrum scanning (by default all operations in the network planning process

are considered to have no interference).

(3) The aim of field test is to get the propagation mode which can reflect

characteristics of planning area propagation environment, which is used to

simulation and network topology structure design (calculating the coverage

distance of related stations).

3

Post-sales staff CDMA Network Planning course

(4) There is no need to do field test in these situations: the customer can provide

applicable radio propagation model; the radio propagation model in the model

database can reflect the characteristics of the radio propagation environment in

the planning area; the network structure is too simple, the model is not to be

corrected.

8. Network topology design: on the basis of collected information, perform the

coverage and capacity plan and design a network topology (witht a group of

planned cell sites) that theoretically meets the customer’s equirements, thus

provide guidance for the subsequent work;

9. Planned sites survey: find the points that can meet the requirements in the

actual environment on the basis of the network topology design. To a larger

network, it should judge whether the sites are qualified by network simulating;

10. Network plan report: to ensure the planning results can be accepted by the

customer, and get the ideas and suggestions about the planning form

thecustomer, it needs to report the result of the first stage to the customer.

11. Simulation: according to the customer’s requirements, perform the adjustments

to the network planning, and present the simulation result;

12. PN plan and neighboring list setting: after the entire sites have been confirmed,

configure the PN and neighboring list;

13. Hand in the network design report: when the planning work is completed,

compose the wireless network design report; the report should be passed the

internal inspection and approval before being submitted to the customer; after

the customer identifies the result (network design report), file the related

reference and data. The project ends.

4

二 Coverage Planning of CDMA System

Keypoint

Familiar with the meaning and value of different parameters in link budget

Coverage planning will be carried out through link budget in the course of CDMA

network design.

Cell coverage of CDMA network is influenced by such factors as antenna height,

antenna type (gain, horizontal beam angle, vertical beam angle, and so on), down tilt

angle and transmitted power. If precise coverage prediction is required, we should take

comprehensive consideration of these parameters when choosing propagation model.

ZTE chooses COST-231 model for 1900M CDMA coverage predictions.

二.1 Link budget introduction

In the cellular system, a BS sector covers such an area where the receiver (BS or

terminal) shall have sufficient signal levels to satisfy service requirements.

In a certain propagation environment, the coverage of a cell directly depends on the

maximum allowable path losses between transmitting and receiving ends, while link

budget can determine the maximum allowable path loss of the specified radio link. In

the link budget, the maximum allowable path loss can be calculated with the following

formula:

Maximum allowed path loss = Transmit power – Receiver sensitivity - Margin - Others

The transmit power refers to the effective transmit power of the antenna and it can be

either the Equivalent Isotropic Radiation Power (EIRP) or Equivalent Radiation Power

(ERP). The formula is as follows:

EIRP = transmit power (dBm) + transmit antenna gain (dBi) - Feeder loss (dB) - body

loss (dB) - Jumper loss (dB) - Other loss (dB)

If the specified antenna gain is in dBd, convert it into dBi in the link budget table.

The receiver sensitivity (Prec) refers to the minimum signal level required at the

receiving end of the antenna with a specified data rate and the worst channel condition.

It can be represented as:

1

(Formular 2.1)

According to the formula (2.1), the receiver sensitivity Prec (dBm) is:

(Formular 2.2)

Note: The actual calculation of receiver sensitivity should also consider the influence

of the system noise figure and loading factor.

Margin and other factors affecting path loss include fading margin, penetration loss and

soft handoff gain.

(1) Fading margin

Fading margin is a reserved margin, based on a full consideration of channel

fading variation, for guaranteeing communication reliability. It corresponds

with a specified cell edge communication probability.

In the radio space propagation, for any given distance, its path loss changes and

can be regarded as a random variable in conformity with lognormal

distribution. The median of path loss is usually adopted in the propagation

model. If the network is designed based on the average path loss, the path loss

at the edge coverage area of the cell will be greater than the path loss median

with a 50-50% probability, that is, the edge coverage probability of the cell is

only 50%. To improve the edge coverage probability of the cell, it is necessary

to reserve the fading margin in advance.

The following takes a cell with a 75% edge coverage probability as an example.

Suppose that the propagation loss random variable is , then is the Gauss

distribution on dB. Set its average value to m, the standard deviation to , and

the corresponding probability distribution function to the Q function. Set a loss

threshold 1 (If the propagation loss is beyond this threshold, the signal strength

will fail to meet the demodulation requirement of the expected service

qualities). The edge coverage probability equal to or greater than 75% can be

represented as:

2

2 Coverage Planning of CDMA System

(Formular 2.3)

For the outdoor environment, the standard deviation is set to 8 dB (This

standard deviation is different for various morphologies. 8 dB is usually for a

small open space with density buildings), and the corresponding margin for the

75% edge coverage probability (communication proportion) can be calculated

with the following formula.

(Formular 2.4)

As shown in Figure 2-3 and Figure 2-4, to guarantee a 75% edge coverage

probability, a margin of 5.4 dB should be reserved during network design. If

requiring a 90% edge coverage probability, in the same calculating method, we

can get the fading margin is 10.3 dB.

Accumulated lognormal probability distribution

Median

Deviation from the median signal m

Figure 2-3 Fading Margin——Probability Distribution Function

3


Figure 2-4 Fading Margin——Probability Density Function

Under specified conditions, edge coverage probability and area coverage

probability are in one-to-one correspondence relationship. In Figure 2-5, the left

vertical coordinate represents the area coverage probability, the right vertical

coordinate represents the edge coverage probability, and the horizontal

coordinate represents the standard deviation/path loss factor. For example, if

path loss factor n = 4 (for a complicated propagation environment), standard

deviation = 8 dB, edge coverage probability = 75%, then the corresponding

area coverage probability is 94%. If path loss factor n = 2 (for a free space),

standard deviation = 8 dB, edge coverage probability = 75%, then the

corresponding area coverage probability is 91%.

Figure 2-5 Edge Coverage Probability and Area Coverage Probability

4


(2) Penetration loss

Penetration loss usually adopts the experience value, depending on the factors

such as construction materials and thickness of building wall in different places.

The descending order of the penetration loss is normally as: dense urban area,

urban area, suburb and rural area. For the link budget, generally the penetration

loss of the dense urban area is 25 dB, urban area 20 dB, suburb 15 dB and rural

area 6 dB. In the actual planning, more accurate penetration loss can be

obtained through test.

(3) Soft handoff gain (only considering two-way soft handoff)

In the CDMA system, the value of soft handoff gain depends on the relevant

coefficient of two propagation paths, log-normal fading deviation and edge

coverage Perl. The specific relationship is shown in Table 2-1.

Table 2-1 Soft Handoff Gain

Perl = 8 dB

Soft handoff gain

0.75 0.5 4.0

0.9 0.5 4.09

0.95 0.5 4.2

0.98 0.5 4.67

Upon determining the above parameters, the maximum allowable propagation

path loss can be calculated, and then the cell coverage range according to the

propagation model (Okumura-Hata model, Cost-231 model and etc).

二.2 Differences between CDMA 1x and EV-DO Link Budget

Comparing the link budget structures of CDMA 1x, EV-DO Rls0 and RevA, the main

differences between them could be listed as following:

Type Link CDMA 1x EV-DO Rls0 EV-DO RevA

Grade of Data

Rate

Forward 9.6kbps~153.6kbps 5

classes

38.4kbps~2.4Mbps 9

classes

38.4kbps~3.1Mbps 11

classes

Reverse 9.6kbps~153.6kbps

5 classes

4.8kbps~1.8Mbps max. 22

classes

5


Type Link CDMA 1x EV-DO Rls0 EV-DO RevA

Terminal Type Forward Single Antenna Single Antenna/Dual Antenna

Body Loss Forward/

Reverse

3dB (Voice)

0dB (Data)

0dB 3dB (Voice)

0dB (Data)

Demodulation

Threshold

Forward All different between 1x and EV-DO,

most are same between EV-DO Rls0 and RevA

Reverse Different

Multi-User

Diversity Gain

Forward N/A Available

1. CDMA2000 1X system

CDMA2000 1X system supports data service besides voice service, the data

rate is up to 153.6kbps. Table 2-3 is a reverse link budget table of CDMA2000

1X system in 800MHz, compared with IS-95A.

The difference between IS-95A and CDMA2000 1X voice service lays in

different demodulation signal noise ratio requirements and interference margin

value. Different demodulation reqirements are due to adoption of CSM5000

chip by CDMA2000 1X base station, so the channel modulation technology is

improved. As to interference margin, we may apply 75% of the maximum

capacity for link budget because the capacity of CDMA2000 1X is more than

that of IS-95A.

The data rate in Table 2-3 is from 9.6kbps to 153.6kbps. The difference

between IS-95A and CDMA2000 1X data service lays in different

demodulation signal noise ratio requirements, interference margin value and

processing gain.

Because either convolutional code or Turbo code can be selected for channel

coding of data service, compared with voice service, the demodulation

requirement for data demodulation decreases. With data rate increasing, the

performance of Turbo code is getting better, the demodulation requirement

decreases.

Due to adoption of advanced technology in CDMA2000 1X system, such as

reverse coherent demodulation, Turbo coding, data coding and convolutional

coding promotion, forward quick power control etc., the capacity of

6


CDMA2000 1X system increases. We use 75% of the top load in link budget,

so the interference margin is increasing to 6.02dB.

Data rate is from 9.6kbps to 153.6kbps provided by 1X system, transmitted in

1.2288MHz bandwidth, so the processing gain is different due to different data

rate. The processing gain is decreasing with the increment of the data rate, i.e.

the receiver sencitivity is increases, and the allowed pathloss is decreased.

Okumura-Hata model is adopted for propagation model in urban area, we can

use related correction factors for different propagation environment. In practice,

we can correct the factors according to calibration model derived from testing.

Table 2-3 is the reverse link budget of CDMA2000 1X 800M System.

7


Table 2-3 Reverse Link Budget of CDMA2000 1X 800M System

8


2. 1X EV-DO system

As a transition from CDMA2000 1X to 3G, 1X EV-DO( named HRPD in

protocol) only provides high data rate service. Due to asymmetry of data

service in forward and reverse direction, the forward link becomes the more

crucial link.

Table 2-4 is the forward link budget table of 1X EV-DO sytem in 800MHz, the

receiver terminal is divided into single antenna type and dual antenna type.

The main difference between IS-95A and 1X EV-DO system are: transmit

power, demodulation signal noise ratio, multi-user diversity gain and receive

diverdity gain, soft handoff gain.

1X EV-DO system uses rate control technology, not power control technology

as in IS-95A and CDMA2000 1X, use full power transmission not part of the

full power for data channel, so the tansmit power of data channel in link budget

is much greater than in IS-95A and CDMA2000 1X, the transmit power is 20W

in the table.

1X EV-DO uses Turbo code in forward direction, the demodulation signal noise

ratio is increasing as the data rate increasing.

As to data service, the terminal can be chosen as a dual antenna one, so there

exist receiving diverdity gain; as to user data dispatch, when multi users share

the common data channel, the system can provide service for those who require

high data rate, that will improve the resource efficiency, increase the system

throughput, thus provides diversity gain.

In 1X EV-DO system, when the user is in handoff state, the terminal will select

the best link and transmits rate requirement only to the base station; the station

transmit data to the terminal; it provides selection gain, called virtual soft

handoff gain.

9


Table 2-4 cdma2000 HRPD system 800M forward link budget

cdma2000 HRPD system 800M forward link budget

Propagation Environment Urban

Channel Type Traffic Channel Control Channel

Receiver Terminal single antenna

dual

antenna single antenna dual antenna

average traffic(or rate)(bps) 9600 9600 38400 38400

average paroxysmal rate(bps) 67132.87 67100 N/A N/A

service time ratio(%) 14.3 14.3 N/A N/A

bandwidth(kHz) 1228.8 1228.8 1228.8 1228.8

bandwidth(dB-Hz) 60.89 60.89 60.89 60.89

BS Tx Power(Watts) 20 20 20 20

BS Tx Power(dBm) 43.01 43.01 43.01 43.01

BS Antenna Gain(dBi) 15.7 15.7 15.7 15.7

BS jumper loss(dB) 1 1 1 1

BS feeder loss(dB/100m) 6 6 6 6

BS feeder length(m) 50 50 50 50

other loss estimate(dB) 1 1 1 1

BS antenna feeder loss(dB) 5 5 5 5

BS EIRP(dBm) 53.71 53.71 53.71 53.71

MS receiver antenna gain(dBi) 0 0 0 0

Body Loss(dB) 3 3 3 3

Noise Figure(dB) 8 8 8 8

Thermal Noise

Density(dBm/Hz) -166 -166 -166 -166

Aim PER(%) 2 2 2 2

each antenna needed Ior/No(dB) -7 -11.6 4 -8

multi-subscribers diversity

gain(dB) 2 2 N/A N/A

receiver diversity gain(dB) N/A 4.6 N/A 12

MS receiver sensitivity(dBm) -112.11 -116.71 -101.11 -113.11

Log-normal normal deviation(dB) 8 8 8 8

Edge Coverage Probability 0.75 0.75 0.75 0.75

Log-normal Fading Margin(dB)

(dB) 5.40 5.40 5.40 5.40

Suppositional Soft Handoff

Gain(dB) 4 4 4 4

Max Allowable Path Loss(dB) 161.42 166.02 150.42 162.42

　　　　　

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cdma2000 HRPD system 800M forward link budget

Propagation Environment Urban

Channel Type Traffic Channel Control Channel

Receiver Terminal single antenna

dual

antenna single antenna dual antenna

Building Penetration Loss (dB) 20 20 20 20

Up Link Path Loss(dB) 141.42 146.02 130.42 142.42

BS Antenna Height(m) 40 40 40 40

MS Antenna Height(m) 1.5 1.5 1.5 1.5

RF Central Frequency(MHz) 870 870 870 870

Hata model Terrain Correction 0 0 0 0

1km Path Loss (dB) 124.31 124.31 124.31 124.31

Slope 34.41 34.41 34.41 34.41

Radius of RF Coverage(km) 3.14 4.28 1.51 3.36

As to reverse direction, 1X EV-DO adoptes CSM5500 chipset compared with

IS95, there are no other great changes in pilot assistant demodulation, handoff,

power control etc.

Table 2-5 shows the reverse link budget of 1X EV-DO system in 800MHz.

Table 2-5 cdma2000 HRPD system 800M reverse link budget

cdma2000 HRPD system 800M reverse link budget 　Propagation Environment Urban

　 1x EV-DO IS-95-A

data rate(bps) 9600 9600

MS rating Tx Power(dBm) 23 23

MS Antenna Gain(dBi) 0 0

Body Loss(dB) 3 3

MS data channel ERP(dBm) 20 20

BS Receiver Antenna Gain(dBi) 15.70 15.70

BS jumper loss(dB) 1 1

BS feeder loss(dB/100m) 6 6

BS feeder length(m) 50 50

other loss estimate(dB) 1 1

BS antenna feeder loss(dB) 5 5

Thermal Noise Density(dBm/Hz) -174 -174

Noise Figure(dB) 5 5

11


cdma2000 HRPD system 800M reverse link budget 　Propagation Environment Urban

　 1x EV-DO IS-95-A

data rate(bps) 9600 9600

Aim PER(%) 1% 1%

Eb/No 3.24 6.80

Loading 0.50 0.50

Interference Margin(dB) 3.01 3.01

BS Sensitivity(dBm) -122.93 -119.37

Handoff Gain(dB) 4 4

Fading Deviation(dB) 8 8

Edge Coverage Probability 0.75 0.75

Fading Margin(dB) 5.40 5.40

Max Allowable Path Loss(dB) 152.23 148.67

　　　Building Penetration Loss (dB) 20 20

Up Link Path Loss(dB) 132.23 128.67

BS Antenna Height(m) 40 40

MS Antenna Height(m) 1.50 1.50

RF Central Frequency(MHz) 825 825

Hata model Terrain Correction 0 0

1km Path Loss A (dB) 123.70 123.69

Slope B 34.41 34.41

Radius of RF Coverage(km) 1.77 1.40

12

三 CDMA Capacity Planning

Keypoint

Know about the factors which affect CDMA capacity, master the method of capacity

planning

During network planning, we need to coinsider the capacity factor besides coverage;

i.e.the planning result should meet the requirments of both the coverage and capacity.

In this chapter, we focus on user prediction, service model and 1X capacity calculation.

三.1 Prediction of the user quantity

三.1.1 Principle of user prediction

The prediction of user quantity is an important base to determine wireless

communication construction scale, determining investment scale of engineering

construction and economic benefit after putting into production.

User quantity prediction should be based on macro development strategy of the city

and country, based on population distribution of the service area and economic

development level and prospects of different parts, thoroughly considering the need for

services according to the local economic development, and the economic bearing

ability of the users.

It’s the precondition of predicting market requirement to master the development law

of cellar wireless communication and clearly realize present development stage of

cellar wireless communication.

The development of user quantity accords with the growing curve law. At the initial

stage, the increase rate is high, because the base is small despite the price is high and

the increase of absolute amount is slow. With the decrease of equipment cost, the

product is gradually accepted by the user and a fast exponential increase period is

inevitable. Then it comes to a stable stage and with an end of saturation stage. As

following:

1


Figure 3-6 Graph of time and communication prevalence rate

Analysis shows that Pakistan is predicted to be in the coming fast expansion period of

cellar wireless communication and the high increase rate is the characteristic of this

stage.

In the following several years, the main features of development environment of cellar

wireless communication are as following:

The economy develops in the continuously fast speed;

The proportion of communication payout in individual income rises gradually;

The cost of communication equipment including terminals continuously

decreases;

Telecommunication charges continue to reduce;

More services kinds;

GOS of the network continues to enhance.

It can be predicted that high increase speed will continue in certain period in cellar

wireless communication marketing and then gradually go to stable development stage.

三.1.2 The method to predict user quantity

1. The way to predict user number

The following methods can be used to predict users’ quantity:

(1) Tendency extrapolation

2

3 CDMA Capacity Planning

Tendency extrapolation is a statistic prediction method to study the

development course of objects. When predicted object shows upward or

downward tendency with time change and no obvious season fluctuation, and a

curve can be found to indicate the change tendency, a tendency model can be

built adopting time as the independent variable and time sequence values the

variables. The main advantage is that it can open out the development future of

things and estimate quantificationally the functions and characteristics.

(2) Recursive prediction

Recursive prediction is to predict the development change of one variable based

on the other variable change. There is certain experience formula between the

two variables, which accords with the tendency distribution relationship of the

two or more variable data (such as average GPD and user number).

The number of users is greatly influenced by economic status and individual

income. If individual average GPD is used to estimate economic status, it is

used as recursive independent variable and conic is adapted to recursively

predict user number.

Conic recursive formula:

Y=0.0004x2-3.3587x+6825.2

Herein: x is individual average GDP of some year, Y is the user number.

(3) Popularity ratio method

Popularity ratio method to predict users combines with analogy analysis,

predict development tendency of the city by deducing analogic city

development trend.

2. The way to predict population scale

The development plan of communication network should be based on

population increase and distribution in plan period. The local user development

can be predicted based on user development information of other areas with

analogic economic status.

3


三.2 Service Model

三.2.1 Voice Service Model

The main indexes of voice service are as follows:

1. Call attempt per user in busy hour;

2. Average conversation time per call;

3. Erl per user in busy hour;

4. GOS

三.2.1.1 Attributes of voice service

1. Every call is a process of voice call setup and release;

2. The resource occupation for one conversation is unchangeable.

三.2.1.2 Call process

Call process is shown in Figure 3-7.

Figure 3-7 call process

三.2.2 Data Service Model

The obvious difference between voice and data service is as follows:

1. Definition of Erlang per subscriber: the definition is related with the proportion

of each service because there are many kinds of data service and the result is

got by statistics;

2. Call attempt: it is up to the service type and proportion;

3. Average conversation time per subscriber: it is up to the service type and

proportion;

4


4. The statistics way of resource occupation is different.

The function of data service model is as follows:

1. Predict data service capacity;

2. Provide the theory reference for system configuration;

3. Provide the theory reference for billing strategy;

4. Provide the theory reference for serving strategy.

三.2.2.1 Attributes of Data Service

Data service has the following attributes:

1. The switch between dormant state and active state;

2. Repetitious call setups are possible for one operation;

3. Data is transmitted by the means of data burst;

4. The resource occupation, for one packet call, varies with data burst and time;

5. The attribute is different for different service type;

6. The attribute is different for different user;

7. The data transmission of FCH is continuous with the speed of 9.6kbps;

8. The data transmission of SCH is by data burst.

三.2.2.2 Setup Procedure of Data Service

The setup procedure of data service is shown as the following figure:

5


Data service of users

Data call session (www service)

Data service of users

Data call session (E-mail service)

Click a web pageClick the next page Click the next page

Active stateActive state Active state

Dormant state

Web page downloadWeb page download

Web page download E-mail download

Receive and send E-mail

Dormant state

6


Figure 3-8 Setup Procedure of Data Service

三.2.2.3 1X data service requirements

1X data service requirements is related to the ratio of different rate service, ratio of

different type service, high-end subscribers and low-end subscriber ratio.

The high-end subscriber distribution is shown in Table 3-6.

Table 3-6 High-end subscriber distribution

High-end Subscribers distribution

Data service rate(kbps) CE number Ratio

9.6 1 25%

19.2 2 40%

38.4 4 30%

76.8 8 4%

153.6 16 1%

Average data service rate of high-end

subscriber (kbps) 26.21 　-

Average CE number 2.73 Convert to multiple of voice traffic

Average data service rate of low-end

subscriber (kbps) 9.6 　-

Average CE number 1 Convert to multiple of voice traffic

High-end Subscribers’ Behavior on Data Service is shown in Table 3-7.

7


Table 3-7 Statistics of High-end Subscribers’ Behavior on Data Service

Statistics of High-end Subscribers’ Behavior on Data Service

Service Type

Informa-

tion on

Demand

WWW/WAP E_MAIL FTP VOD/AODE-COMM-

ERCEOTHER

Average Use Times per Month 60 60 60 60 5 20 15

Concentration Factor of Busy Day 5% 5% 5% 5% 5% 5% 5%

Use Times per Busy Day 3 3 3 3 0.25 1 0.75

Concentration Factor of Busy Hour 10% 10% 10% 10% 10% 10% 10%

Use Times per Busy Hour 0.3 0.3 0.3 0.3 0.025 0.1 0.075

Average Duration of Each Use (S) 120 300 15 30 300 120 60

Duty Factor 0.1 0.1 0.75 0.8 0.8 0.1 0.1

Average Actual Occupying Time during

Each Use (S) 12 30 11.25 24 240 12 6

Average Data Rate, R (bps) 26210 26210 26210 26210 26210 26210 26210

Throughput per Busy Hour (bps) 26.21 65.53 24.57 52.42 43.68 8.74 3.28

Throughput per Busy Hour [Total of All Data Services] (bps) 224.43 Value 250

Traffic (mErl) 1 2.5 0.94 2 1.67 0.33 0.13

Traffic [Total of All Data Services]

(mErl) 8.57 Value 10

Low-end Subscribers’ Behavior on Data Service is shown in Table 3-8.

Table 3-8 Statistics of Low-end Subscribers’ Behavior on Data Service

Statistics of Low-end Subscribers’ Behavior on Data Service

Service Type

Informa-

tion on

Demand

WWW/WAP E_MAIL FTP VOD/AOD

E-

COMMERC

E

OTHER

Average Use Times per Month 30 30 20 30 0 10 10

Concentration Factor of Busy Day 5% 5% 5% 5% 5% 5% 5%

Use Times per Busy Day 1.5 1.5 1 1.5 0 0.5 0.5

Concentration Factor of Busy Hour 10% 12% 10% 10% 10% 10%

Use Times per Busy Hour 0.15 0.18 0.1 0.15 0 0.05 0.05

Average Duration of Each Use (S) 120 300 15 30 0 120 60

Duty Factor 0.1 0.1 0.75 0.8 0 0.1 0.1

Average Actual Occupying Time during

Each Use (S) 12 30 11.25 24 0 12 6

8


Average Data Rate, R (bps) 9600 9600 9600 9600 9600 9600 9600

Throughput per Busy Hour (bps) 4.8 14.4 3 9.6 0 1.6 0.8

Throughput per Busy Hour [Total of All Data Services] (bps) 34.2 Value 35

Traffic (mErl) 0.5 1.5 0.31 1 0 0.17 0.08

Traffic [Total of All Data Services]

(mErl) 3.56 Value 3.5

Traffic model in busy hour is shown in Table 3-9.

Table 3-9 Traffic model in busy hour

Subscriber category Voice only Voice & Data

Subscriber Ratio 1-

Average voice traffic in busy hour per subscriber ErlEv 0.02 0.02

Average data traffic in busy hour per High-end Subscribers mErl 45.42 -

Average data traffic in busy hour per Low-end Subscribers mErl 24.17 -

Data Subscriber proportion - k

High-end Subscriber proportion - * k

Low-end Subscriber proportion - * 1-k

Capacity requirement calculation for 50,000 subscribers’ exchange is shown in Table

3-10.

Table 3-10 Capacity requirement calculation for 50,000 subscribers’ exchange

Voice Ev(Erl) 0.02 0.02

High-end subscriber Ed(mErl) 45.42 45.42

Low-end subscriber Ed(mErl) 24.17 24.17

1 0.2

Total subscriber 50000 50000

Voice subscriber 50000 50000

Data subscriber 50000 10000

BSS voice traffic Erl 1000 1000

High-end subscriber ratio K 0.8 0.8

High-end data subscriber 40000 8000

Ligh-end data subscriber 10000 2000

High-end data traffic Erl 1816.8 363.36

High-end data traffic Erl 241.7 48.34

9


High-end average data rate (kbps) 26.21 26.21

Average CE number 2.73021

2.73020

8

Low-end average data rate(kbps) 9.6 9.6

Average CE number 1 1

BSS data service unified to voice service traffic Erl 5201.94

1040.38

9

BSS total traffic Erl 6201.94

2040.38

9

三.3 Capacity calculation of CDMA2000 1X system

CDMA2000 1X system supports both voice and data services.

三.3.1 The ultimate capacity of isolated BTS

Let’s see a simpler case firstly, the system supports m voice users with the rate Rv, requiring

demodulation under FER of 1%, meanwhile there are n data users with data rate

Rd, requiring demodulation under some FER. Supposed that terminal signal of

voice service reaches BS with power Pm and signal of data service Pd, the terminal signals

of all service types should be the same when reaching the BS if the power control is ideal, so

the total received power of BS should be:

(Formular 3.1)

Herein No is the sum of system noise and interference from other system, and here the

voice activity factor is not concerned, change (Formular 3.1) into:

(Formular 3.2)

(Formular 3.3)

For voice user,

(Formular 3.4)

10


or

(Formular 3.5)

(Formular 3.6)

For data service,

(Formular 3.7)

or:

(Formular 3.8)

(Formular 3.9)

Now we are discussing the ultimate capacity of the system, so:

(Formular 3.10)

And

(Formular 3.11)

Simplify (Formular 3.3) into:

(Formular 3.12)

11


Take (Formular 3.6) and (Formular 3.9) into (Formular 3.12):

(Formular 3.13)

Concerning voice activity factor Va in (Formular 3.13), then:

(Formular 3.14)

If there are many types of data services, then the ultimate capacity formula should be:

(Formular 3.15)

三.3.2 BS capacity in cellar system

BS in the cellar system will receive interference from other surrounding BS, so the

capacity will decrease compared with the isolated island case. The impact from

surrounding BS is decided by network planning result. Well-designed network planning

will greatly reduce mutual impact from other BS in the system, improving the capacity

of the whole system.

The impact from other surrounding BS is related to practical wireless environment,

denoted by a factor f, which is the percentage of interference from other cell of the

interference from the BS itself just as in IS95 system. If Isc is used to indicate the

interference from the BS itself, Ioc is the interference from other cells, then:

(Formular 3.16)

Therefore,

(Formular 3.17)

12


Obtain capacity formula in cellar system, adopting similar derivation process to

isolated BS condition:

(Formular 3.18)

In omni cellar BS group, if the users are distributed uniformly, the f value is 60% or so

in theory. ZX3G 1X system greatly improves the system capacity through enhancing

air interface performance; by adding reverse link pilot, supporting reverse link

correlative demodulation, effectively reduce required signal noise ratio for

demodulation; changing forward link BPSK into QPSK and adding forward link fast

power control enhance the forward link capacity. The following formula can be used to

indicate channel number supported simultaneously by each cell of ZX3G 1X system:

(Formular 3.19)

Herein:

- m: voice channel number;

- Va: voice activity factor;

- W/R: spreading gain;

- i: all the possible data service types;

- n: the number of data service channels of same type;

- f: the ratio of interference from other cells to interference from the cell itself;

- Loading: the designed load of the system.

三.4 EV-DO capacity planning

The "capacity" here implies two aspects: subscriber quantity and throughput. And In

this paper, the "throughput" specially means the data flow on the physical layer; if it

needs to be converted to the throughput on the application layer, the conversion can be

conducted according to the formula below:

13


Throughput on application layer = Data rate on physical layer × 80%

三.4.1 Active Subscribers Quantity per Sector

In EV-DO system, being restricted by the count of preamble of forward traffic channel

(MACindex), the maximum active subscriber quantity per sector is 59 theoretically. In

the early 2005, ZTE Corporation achieved 59 users with data downloading

simultaneously in one sector in practice tests, verifying the exact match of practical

situation with the theoretical result.

In the common commercial network, there are more considerations, such as QoS,

system stability, configuring features of channel board, etc. so it is recommended that

the maximum active subscriber quantity per sector is set to 30 or so.

三.4.2 Recommended Sector Throughput

According to the theoretical calculation and practice testing result, we recommend that

in normal cellular environment the sector forward throughput is 1.4 Mbps, and the

sector reverse throughput is 500 kbps.

三.4.3 Analysis on Sector Reverse Throughput

In the EV-DO system, all subscribers share the same frequency band; hence on the

reverse link, when the terminal does not have enough power to overcome the

interference from other users, the network attains its maximum reverse capacity.

三.4.3.1 Reverse Throughput of single Sector

For the sake of simplicity, consider the EV-DO system capacity of single cell first.

Suppose that the system can support up to n active data subscribers, the data rate is RD,

and under the specified PER, the required demodulation threshold is , where,

Eb/Nt is the ratio of energy per bit to noise spectral density, and it is the demodulation

threshold on the BTS side. Suppose that the power strength of data traffic signal of

terminal is Pd when it arrives at the BTS side; and under the ideal reverse power

control condition, the strengths of all user’s signals are the same when they arrive at

the BTS side, so the BTS's total received power is:

14


(Formular 3.20)

Where, No is the thermal noise. Suppose all the users have the same data rate, omitting

the thermal noise, it can be deduced from the equation (Formular 3.19) the formula

about the capacity:

(Formular 3.21)

Where,

W: frequency bandwidth, 1.2288MHz;

RD: data service rate, such as 9.6kbps, 19.2kbps … 153.6kbps;

: Demodulation threshold of BTS side; it varies with data rates, channel

environments and PERs

In some specified moving channel environment and with the 2% PER demand, the

demodulation threshold can be measured out in the laboratory. Using this threshold and

the Formular 3.21, it can be calculated the maximum subscriber quantities at different

data rates and then the maximum sector reverse throughputs at different data rates, as

shown in Table 3-11:

Table 3-11 Reverse Throughput Calculation of single Sector

Reverse Data Rate (kbps)

Channel:30km/h, 1path, 2Antenna, 800MHz

Eb/Nt(dB)Max. Subscriber

Quantity

Total Throughput of

Reverse Sector (kbps)

9.6 3.67 56.0 537

19.2 2.66 35.7 685

38.4 1.75 22.4 859

76.8 2.24 10.5 810

153.6 5.23 3.4 522

15


In real cases, subscribers do not have the same data rates, meanwhile, the radio channel

environment differs from that in the table (for example most of users stay in the

stationary environment), and therefore the practical reverse throughput of single sector

is different from its theoretical calculation. But tests show that the difference between

them is not big.

三.4.3.2 Cellualr sector reverse throughput

In the commercial cellular network, there also exist interferences from surrounding

sectors, so the capacity in this case is obviously less than that of single sector. Suppose

that the ratio of adjacent cells' interference to local cell interference is f, and then the

Formular 3.21 can be transmitted into:

(Formular 3.22)

For example, an omni cell, its interference factor is f=0.6, then the calculation of the

reverse sector throughput is like follows:

Table 3-12 Reverse Throughput Calculation of Cellular Sector

Reverse Data Rate (kbps)

Channel:30km/h, 1path, 2Antenna, 800MHz

Eb/Nt(dB)Max. Subscriber

Quantity

Total Throughput of

Reverse Sector (kbps)

9.6 3.67 36 346

19.2 2.66 22.3 428

38.4 1.75 14 538

76.8 2.24 6.6 507

153.6 5.23 2.1 323

三.4.4 Sector forward throughput

The sector forward throughput of EV-DO is mainly influenced by such factors:

1. Forward scheduling algorithm;

16


2. The geographic distribution of subscribers in the sector; under the cellular

condition, it can be considered that the sector coverage area shrinks to some

extent;

3. Radio channel condition (including the velocity of mobile terminal)

4. Terminal type (single- or dual-antenna terminal and terminal model).

三.4.4.1 Forward Scheduling Algorithm

On the EV-DO forward link, it is time division multiplex. The multiplexing mode is

mainly controlled by the forward scheduling algorithm, so the algorithm has a great

effect on the forward throughput. Currently, the widely used algorithm is the

proportional fair scheduler developed by the Qualcomm Company. Here we will briefly

introduce this algorithm.

Suppose that there are multiple users in the system, in the time slot n, each subscriber k

maintains a scheduling variable Tk[n] that reflects the average throughput; the data rate

applied for by the subscriber k is DRCk[n]. Whenever transmitting a new packet, the

scheduler conducts the following two steps:

1. Taking the ratio of

DRCk[n]/Tk[n] (Formular 3.23)

as the criterion, select the subscriber with the largest ratio as the user to be

served in this time slot;

2. According to the following formula, update the Tk[n],

(Formular 3.24)

Sk[n] =lk[n]*Nk[n]

Where, tc=1024 time slots

If lk[n] is the time slot length occupied by the packet scheduled the last time

slot, and its rate is Nk[n];

If the subscriber k was not scheduled in the last time slot, then Sk[n] = 0.

Here is the flow chart of the algorithm:

17


Figure 3-9 Flow Chart of Forward Scheduling Algorithm

三.4.4.2 Features and Expectations of Forward Sector Throughput

According to the simulated result based on above algorithm, we obtain the main

features about the forward sector throughput:

18


1. When multiple subscribers are simultaneously downloading and the duration is

long enough, slots serving for each subscriber appear a trend of even allocation,

which makes the accumulated subscriber's throughput be in direct proportion to

the data rate applied by the subscriber DRC;

2. When using this scheduling algorithm, the total forward sector throughput is

mainly determined by subscribers' geographic distribution in sector;

3. Considering that subscribers are stationary, when they assemble in the near-cell

areas, the forward sector throughput is expected to attain about 2 Mbps; when

subscribers are distributed evenly in the sector, the forward sector throughput is

expected to be 0.8~1.4Mbps, and when subscribers gather in the far-cell area,

the expected throughput is 300~600 kbps.

The practical tests show that the real forward sector throughput is very close to the

above simulated values.

三.4.5 Simplified EV-DO Data Traffic Model

We have discussed the ultimate quantity of active subscribers, and forward/reverse

throughputs of air interface in the previous contents. Now we will discuss the

simplified EV-DO data traffic model, which will be taken as the criterion on

calculating the network capacity configuration.

The simplified data traffic model does not distinguish all kinds of packet data traffic

applications such as website viewing, e-mail, web chatting, etc, but looks them as an

integration. This is because that whatever types of the data traffic are they basically

belong to the packet traffic and accord with the fundamental features of packet data

traffic. The model only describes the scale and average indexes of the system packet

data traffic, so we can make a macroscopical statistics of all kinds of packet data

traffic. This model simplifies the complex situations and has great practicability.

A session is a process during which the user logs on the network and completes his

conversation, i.e. the process from the user' logging on to his logging off. A session

may include multiple active and dormant states; each active state further contains

multiple sub-states including Data Transfer state with data reception/transmission and

Tad state without data reception/ transmission. The significance of the Tad state is to let

the system regularly release the resources occupied by the subscriber who has not used

the network for a long time, which is beneficial for improving the system utilization.

19


The Maximum duration of the Tad state depends upon the parameter set on OMC,

where it can be modified.

Following figure shows one session process of a subscriber who experiences only two

Active states before logging off.

Figure 3-10 Session in the Data Service

It should be noted that when the terminal is in Active state, it occupies air interface and

CE resource of the sector, if it stays in Dormant or Idle state, no resource occupation

occurs. Therefore, the key factor influencing the system throughput and capacity is the

user's behavior in Active state.

Here we present a simplified traffic model of EV-DO, same as EV-DO Release 0,

which describes macroscopically the requirements of packet data traffic subscriber and

his behavior features. Parameters in the model are all set default values, which should

be revised or adjusted in practical case according to the customer's demands or local

real situations.

20


Table 3-13 A Simplified Data Traffic Model of EV-DO

ID Parameter Unit DefaultDescription/

RelationshipInput/Output

B Quantity of Packet Data User - -

Subscriber quantity to be

number-allocated:

provided by customer's

prediction

Input

D Average Session Duration s 300

Average duration

between user's logging in

and logging off: user

habit

Recommend as

input

G Active Ratio in One Session % 40%

Ratio of Active state

when on line, the

remaining is Dormant

state ratio: user habit

Recommend as

input

HBusy Hour Sessions per

Subscriber- 0.3

Network use frequency

of subscriber

Recommend as

input

C Average Size kByte 1200

Average total data

throughput in one

session, including

forward and reverse

links: user habit

Recommend as

input

IData Service Ratio of Uplink and

Downlink (R1:R2)- 1:4

Ratio of user's

uploading throughput to

downloading throughput:

user habit

Input

S Soft Handoff Ratio % 35%It is related to the

network layout.Input

EPercentage of on-line Packet Data

Users% 3%

Percentage of on-line

subscribers (including

Active and Dormant) in

total subscribers

D*H/3600

Recommend as

output

VfAverage Active Forward

Throughputkbps 64

Average throughput of

active forward link

C*8/(D*G)*(R2/(R1+R2

))

Recommend as

output

VrAverage Active Reverse

Throughputkbps 16

Average throughput of

active reverse link

C*8/(D*G)*(R1/(R1+R2

))

Recommend as

output

21


In this model, parameters such as Vf, Vr and E are not independent variables, which

can be calculated from other parameters. In general, it is recommended to input C, D,

G and I, and output Vf and Vr.

Most of data service can use this data traffic model, but for some special service, such

as VoIP, the voice traffic model may be more suitable. Here we recommend that the

sector quantity needed can be calculated separately for each different service, and sum

of them is the planning result meeting the capacity requirement.

三.5 Planning case

The case described below is in H district of S city, we take it as an example for

introducing the working processes in the stage of network planning.

三.5.1 Coverage object

H district is located at longitude 114˚26’ E and latitude 22˚33’ N. It has nine

administrative villages, namely: Liuyue, Henggang, Silian, Anliang, Xikeng, Dakang,

Bao’an, He’ao, and Huanggekeng, and 1 residental committee, totaling 52 natural

villages; and the H district have an area of 81.2 square km.

H district has a hilly topography. It is mainly composed of hills (54.3%), bench terrace,

and alluvial plains (13.4%). The plains primarily cover the stripe of land north to Xu

Town and along the Shenhui Highway as well as the areas around Anliang and Xikeng,

with an average height of 40~60m. The western and southern parts are mainly bench

terrace. The Shizishi district in the south and the Yuanshan Mountain in the east are

mainly elevated hills with a height of 300~500m.

H district is an important transportation hub in eastern S city. The Shenhui first-rate

highway runs through the town, Huiyan port dispersion freeway and Jihe freeway have

already opened for service, and the Pingyan port dispersion railroad runs through the

town from the north to south. The town proper has a very convenient transportation

network, with the main and secondary trunk roads and tributaries totaling over 90 km

in length.

Some of the areas in H district have very-dense population distribution, and a very

rough and complex topography. Therefore the field test should be conducted.

22


The population of H district totals 400,000~500,000, among which, 20,000~30,000 are

local residents. The central areas of the town are located in Liuyue, Henggang, and

Silian. The Town government, hotels, key shopping centers, high-grade estates, leisure

plazas, places of entertainment all scatter in the central areas. The people’s income

level of the area is relatively high and thus the area should to be covered as the focus

area, and traffic load sharing should be given consideration; the area north to Henggang

Village and Bao’an, He’ao, Dakang are mainly industrial zones with large-scale low

factories and migrating workers. The migrating workers are a very large group of

potential subscribers, but because they have a relatively low income level, the major

target of network building should focus on the coverage scope at the early stage;

Anliang, Xikeng, and Huanggekeng are predominately rural areas and have relatively

few industrial zones, and the population density and income level are both low,

therefore, the major target in these areas also focus on the coverage scope.

The network building in this phase consentrates along the Shenhui Highway,

guaranteeing the coverage in central areas, namely, Liuyue, Henggang, and Silian, and

the high-grade estates. The key covered areas are shown in Figure 3-11. Cover the

roads of Shenhui Highway and Jihe Freeway as key areas, guaranteeing the continuous

coverage of the joining area of the two roads in Henggang.

23


Figure 3-11 Coverage area and key covered areas in H district

三.5.2 Project requirements

In the urban areas, it is not allowed to build iron towers. So the antenna height can only

be increased by the ways of antenna pale or rack.

The site should be close to the transmission access point as much as possible.

三.5.3 Link budget

Lingk budget model of 1.9GHz is derived from corrected model according to practical

environement based on standard COST231model. Link budget can only predict base

station coverage approximately, the real coverage shloud be obtained by testing.

During network optimization, it is necessary to adjust the antenna height, downtilt

angle and transmit power to meet coverage requirements of every BTS.

24


Table 3-14 is the reverse link budget result for 1.9GHz system.

Table 3-14 Reverse link budget result

Parameter Ban Tian Long Hhua Lian Tang

MS Nominal Tx Power(dBm) (dBm) 23.00 23.00 23.00

MS Antenna Gain(dBi) 0.00 0.00 0.00

Body /Vehical Loss(dB) 3.00 3.00 3.00

MS ERP(dBm) 20.00 20.00 20.00

BS Antenna Gain(dBi) 17.10 17.10 17.10

BS Jumper Cable Loss (dB) 1.00 1.00 1.00

BS Feeder Loss(dB/100m) 6.00 6.00 6.00

BS Feeder Length(m) 50.00 50.00 50.00

Other Loss (dB) 1.00 1.00 1.00

BS Antenna& Feeder Loss (dB) 5.00 5.00 5.00

Thermal Noise Density(dBm/Hz) -174.00 -174.00 -174.00

Data Rate (bps) 9600.00 9600.00 9600.00

Noise Figure(dB) 5.00 5.00 5.00

Eb/No 7.00 7.00 7.00

Loading 0.50 0.50 0.50

Interference Margin(dB) 3.01 3.01 3.01

BS Sensitivity (dBm) -119.17 -119.17 -119.17

Soft Handoff Gain(dB) 4.00 4.00 4.00

Fading Deviation (dB) 8.00 8.00 8.00

Edge Coverage Probability 0.75 0.75 0.75

Fading Margin(dB) 5.40 5.40 5.40

Max Allowable Path Loss(dB) 149.87 149.87 149.87

Building Penetration Loss (dB) 28 28.00 28

Up Link Path Loss(dB) 119.87 121.87 122.87

BS Height(m) 30.00 30.00 30.00

MS Height(m) 1.50 1.50 1.50

Frequency (MHz) 1975.00 1975.00 1975.00

A(dB) 12.26 45.80 16.87

B 40.52 30.24 39.10

Radius of BS Coverage (m) 452.24 327.40 513.59

25


三.5.4 Capacity requirement

At present, the number of the fixed telephone in H Branch is near 50,000 lines, which

are located at 21 access points, two of the access points are overlapping bureau, one

access points is not working. The amount of telephone subscribers of each point is

shown in Table 3-15.

Table 3-15 Names of access points and the number of allocated telephone in Henggang Branch Bureau

No. Access Point

Number of

Allocated

Telephone

subscribers

No. Access Point

Number of

Allocated

Telephone

subscribers

1Liuyue China Telecom

Equipment Building8638 2

Henggang China Telecom

Equipment Building8457

3 New World Plaza 2124 4 Huaxi Village 1526

5 Silian Villager Committee 5309 6 Kangle Garden 511

7 Town Government 1268 8 Tangkeng Villager Committee 1305

9 Longsheng Garden 846 10 Anliang 2782

11 Dakang 3052 12 Xikeng 1823

13 Henggang Law Court 1659 14 He’ao 1095

15 Aobei 2432 16 Dafu 1691

17 Bao’an 1630 18 189 Industrial Zone 1350

19 Shenkeng Village Not open

三.5.5 Solution

Solution to the above coverage and capacity requirements is shown in Table 3-16.

Table 3-16 Solution to coverage

No. Site Sector Site

typeLongitude Latitude

Antenna

type

Antenna

height

Sector

direction

Downtilt

angle

Coverage

radius

1

Henggang

Equipment

Building

a S111 114.205972 22.647694 65 30 0 4 0.5

1 Henggang

Equipment

b S111 114.205972 22.647694 65 35 120 1 1

26




Antenna

type

Antenna

height

Sector

direction

Downtilt

angle

Coverage

radius

Building

1

Henggang

Equipment

Building

g S111 114.205972 22.647694 65 35 250 1 1

2Town

Governmenta S111 114.193417 22.645806 65 36 0 3 0.6

2Town

Governmentb S111 114.193417 22.645806 65 36 110 1 1.5

2Town

Governmentg S111 114.193417 22.645806 65 36 220 3 0.6

3

Liuyue

Equipment

Building

a S111 114.187250 22.639583 65 35 0 2 0.8

3

Liuyue

Equipment

Building

b S111 114.187250 22.639583 65 35 120 0 1

3

Liuyue

Equipment

Building

g S111 114.187250 22.639583 65 35 240 0 1

4Shenkeng

Villagea S111 114.171167 22.638444 65 26 120 0 1

4Shenkeng

Villageb S111 114.171167 22.638444 65 26 240 0 1

4Shenkeng

Villageg S111 114.171167 22.638444 65 26 340 0 1

5Kangle

Roada S111 114.183570 22.647570 65 26 0 0 1

5Kangle

Roadb S111 114.183570 22.647570 65 26 100 3 0.6

5Kangle

Roadg S111 114.183570 22.647570 65 26 220 0 1

6Paibang

Road a S111 114.192250 22.656806 90 26 0 0 1

6Paibang

Roadb S111 114.192250 22.656806 65 26 120 4 0.5

6Paibang

Roadg S111 114.192250 22.656806 65 26 240 2 0.8

7 Datang New

Village

a S111 114.199500 22.653167 65 26 0 4 0.5

27




Antenna

type

Antenna

height

Sector

direction

Downtilt

angle

Coverage

radius

7Datang New

Villageb S111 114.199500 22.653167 65 26 120 4 0.5

7Datang New

Villageg S111 114.199500 22.653167 65 26 240 4 0.5

8Dalong bag

factorya S111 114.204667 22.654778 65 26 0 4 0.5

8Dalong bag

factoryb S111 114.204667 22.654778 65 26 120 0 1

8Dalong bag

factoryg S111 114.204667 22.654778 65 26 240 4 0.5

9Guangda

Roada S111 114.204510 22.659510 90 26 0 0 1

9Guangda

Roadb S111 114.204510 22.659510 65 26 120 0 1

9Guangda

Roadg S111 114.204510 22.659510 65 26 240 4 0.6

10

Xin

Quansheng

Seafood

Restaurant

a S111 114.212940 22.662670 65 27 40 0 1

10

Xin

Quansheng

Seafood

Restaurant

b S111 114.212940 22.662670 65 27 120 0 1

10

Xin

Quansheng

Seafood

Restaurant

g S111 114.212940 22.662670 65 27 230 4 0.6

11 992 Factory a S111 114.208611 22.670444 90 26 80 0 1

11 992 Factory b S111 114.208611 22.670444 90 26 200 0 1

11 992 Factory g S111 114.208611 22.670444 90 26 320 0 1

12

He’ao

Police

Station

a S111 114.222694 22.678389 65 23 0 0 1

12

He’ao

Police

Station

b S111 114.222694 22.678389 65 23 110 0 1

12 He’ao

Police

g S111 114.222694 22.678389 65 23 240 0 1

28




Antenna

type

Antenna

height

Sector

direction

Downtilt

angle

Coverage

radius

Station

13Yuanshan

Gardena O1 114.241163 22.642345 360 20 360 0 1

14Dafeng

Villagea S111 114.236480 22.648650 90 23 0 0 1

14Dafeng

Villageb S111 114.236480 22.648650 90 23 120 0 1

14Dafeng

Villageg S111 114.236480 22.648650 90 23 240 0 1

15

East City-

loop Road

of

Shangzhong

Village

a S111 114.221900 22.646970 65 26 60 0 1

15

East City-

loop Road

of

Shangzhong

Village

b S111 114.221900 22.646970 65 26 200 0 1

15

East City-

loop Road

of

Shangzhong

Village

g S111 114.221900 22.646970 65 26 300 0 1

17

An’liang

Villager

Committee

a S111 114.214028 22.632889 65 23 50 0 1

17

An’liang

Villager

Committee

b S111 114.214028 22.632889 65 23 160 2 0.8

17

An’liang

Villager

Committee

g S111 114.214028 22.632889 65 23 310 0 1

18

North

Baotong

Road

No.102

a S111 114.217940 22.621640 90 17 5 2 0.8

18 North

Baotong

b S111 114.217940 22.621640 63 17 130 0 1

29




Antenna

type

Antenna

height

Sector

direction

Downtilt

angle

Coverage

radius

Road

No.102

18

North

Baotong

Road

No.102

g S111 114.217940 22.621640 63 17 215 0 1

21He’ao Road

No.70a S111 114.217970 22.684410 90 23 0 0 1

21He’ao Road

No.70b S111 114.217970 22.684410 90 23 120 0 1

21He’ao Road

No.70g S111 114.217970 22.684410 90 23 240 0 1

22Jihe

Highway1a S110 114.196150 22.676540 90 10 60 0 1

22Jihe

Highway1b S110 114.196150 22.676540 90 10 240 0 1.5

23Jihe

Highway2a S110 114.177410 22.655600 90 10 60 　 1.5

23Jihe

Highway2b S110 114.177410 22.655600 90 10 270 　 1.5

24

Henggang

High

School

a S110 114.221417 22.660389 65 26 60 0 0.7

24Henggang

High Schoolb S110 114.221417 22.660389 65 26 240 0 1

24Henggang

High Schoolg S110 114.221417 22.660389 65 26 320 0 1

25Rongmei

Schoola S110 114.226250 22.635430 65 25 45 0 1

25Rongmei

Schoolb S110 114.226250 22.635430 65 25 230 0 1

25Rongmei

Schoolg S110 114.226250 22.635430 65 25 340 0 1

26

Henggang

Primary

School

a S110 114.207100 22.639630 65 26 0 0 0.6

26 Henggang

Primary

School

b S110 114.207100 22.639630 65 26 120 0 0.6

30


31

四 Site Survey and Planning

Keypoint

Familiar with the meaning and value of different parameter in link budget

四.1 Overview

It can be seen from the network planning procedure that many principles should be

followed during the network planning.

The position of site survey in network planning is shown in Figure 4-12.

Figure 4-12 Position of site survey in network planning

四.2 Introduction of site survey

Network planning deals with available sites survey and planned sites survey. The

available sites information can be gotten from communication with the operator;

planned sites information can be obtained during site planning stage.

The operator provided sites survey is not always done during available sites survey

stage, we can determine whether survey is needed for part or all the available sites

based on project manager’s knowledge of the planned environment. It is possible that

we just make survey of some important sites, as the base of network topology, the other

1

available sites are left for determine whether need survey during planned sites survey

stage. The available sites provided by operator which meet the network topology

requirements will be set as the primary sites during planned sites survey stage.

In village/road network planning stage, the available sites may be dispersedly, so it is

difficult to make a survey of all the sites. The project manager can design the network

topology base on the distribution of the available sites according to the detailed

situation. Other sites can be selected only when all the available sites are not suitable.

四.3 Site Selecting Principles

Before conducting the site survey during the network planning, it needs to select

appropriate sites among the sites provided by the customer and those planned sites.

Here are the basic requirements for qualified sites:

1. Orientation: there should be no obvious barrier, which may result in coverage

failure in some areas;

2. Height: at the station of urban area, the antenna height should be 10-15 meters

higher than surrounding buildings (in very densely urban area, the antenna

height can be about 10 meters higher); in suburb, the antenna height is over 15

meters higher, whose height is determined according to the required coverage

range; in terms of the planned site station, the height of surrounding buildings

must not over 1.3 times than that of the planned antenna height;

3. Interference: avoid interference with other network systems; select the sites

where there is no interference or the problem of existing interference can be

solved;

4. GPS: the solid angle should be over 90 degree (the part of the surface area of

the celestial body that can be seen from the GPS location should account for no

less than one fourth of the whole surface area, i.e. it should be no less than R2 ,

as the surface area of a sphere equals to 4R2);

5. Antenna feeder: there is enough space for installing the antenna and feeder on

top of the building /tower;

6. Basic conditions: equipment room should be available; the transmission and

power supply must be manageable;

2

4 Site Survey and Planning

7. Site location: the distance between the actual location and the planned location

of the site station can not exceed one fourth coverage radius.

The above requirements can be reached by adjusting the parameters, for example, when

the antenna height is not enough, it can be mended by building a tower and heightening

the mount or pole; if there exist barriers in some direction, the sector in this direction

can be cancelled under the condition that the network topology will not be affected;

etc.

Below, we will discuss the first three requirements in detail.

四.3.1 No Obvious Barrier Directly Opposite Sector

Barriers have great influence on the coverage. They may result in such problems: in the

back area of the barrier a shadow always occurs, which easily produces blind coverage

area; the signal is easily reflected by barriers, which will bring pilot pollution to the

opposite direction, and so on.

It is inevitable that there are buildings around a site. The building’s blocking effect on

the site is related to three parameters: beamwidth, the distance from the antenna main

lobe to the building, and the building size (width or height).

It can be judged whether there exists serious interference through the following simple

standards:

1. To a relatively large building, the judging standard for “serious barrier” is

whether the whole antenna main lobe is obstacled. Currently, the common

antennas have large horizontal beamwidth and small vertical beamwidth (i.e.

vertical lobe angle). Thus, the vertical beam is more likely to be blocked.

Suppose, the vertical lobe angle is , the building is H meters higher than the

antenna and the distance between the building and the site is L, then in order to

avoid the obstacle in the vertical direction, L should satisfy the condition of

L>H/tg(/2).

For example: If the vertical lobe angle is 7, and the height difference is 20

meters, then the distance should be L>330 meters.

2. For a relatively small barrier, to avoid serious obstacle, the distance from the

barrier to the site should meet:

L > 2**(180/(*))2 : wavelength.

3


For example:

f = 800M: = 7 L > 50 m; = 16 L > 10 m;

f = 1900M: = 7 L > 22 m; = 16 L > 5 m.

四.3.2 Requirement for Site Height

In order to satisfy the coverage requirement, there is certain requirements for the

antenna height: to the site in urban area, the antenna height should be 10-15 meters

higher than surrounding buildings (in very densely urban area, the antenna height can

be about 10 meters higher); to stations in suburb and country, the antenna height should

be over 15 meters higher than surrounding buildings and its height is determined

according to the required coverage range;

If the antenna is too high, for example, in urban area, when the antenna height is more

than 20 meters higher than the average height of surrounding buildings, it maybe

occurs that the signal radiation covers too large and thus produces interference to the

neighboringing sites; if the antenna height is more than 60 meters, a blind area may

appear near the antenna or the indoor scope near the base station. In practical case, the

blind areas near the antenna ever occurred due to over-high antenna, which is at last

solved by lowering the antenna height (moving the antenna from the tower down to the

building top or changing the site location (to avoid over-high building).

If the antenna is too low, for example, in suburb, when the antenna height is less 10

meters than the average height of the surrounding, the coverage maybe is too small and

can not meet the requirements. Generally this problem can be solved by heightening

the antenna such as heighting the pole, mount or rack; but one thing must be

guaranteed, that is, the site station must possess the bearing ability for antenna

heightening. For example, if the site building does not belong to framework structure

(which is a kind of building constructing method, generally, build the framework with

reinforcing steel bars and concrete first, then build the non-load bearing walls on the

basis of the framework), then the tower can not be built definitely on it.

To the planned sites, it is required that the available antenna height should be close to

its planned height. If the building can be heightened, then the current antenna height

can be lower than the planned height; but note that the building height can not be 30%

higher than the planned height, because under this condition, it is hard to control the

antenna height which thus results in the over-large coverage. If there is a tower on the

4


building top, the planned height should better be between the heights of building top

and the tower top platform.

As for some very low sites required by the customers, such as the customer’s

equipment building where the transmission and power supply are provided, the

building can be used as a site if it satisfys the conditions of without obvious barrier and

with bearing ability, ect, and the antenna height requirement can be met through

heightening the pole or mount, tower, etc.

四.3.3 Avoiding Mutual Interference with Other Systems

The CDMA system may interfere in other systems and can receive the interference

from other systems. This problem should be taken into consideration during the

network planning.

To different wireless systems whose frequency bands overlap, there must be mutual

interference between them. For 450M CDMA system, this problem often occurs and

can be solved only by clearing the overlapping frequencies. Neighboringing

frequencies may also cause interference as outband suppression capability of the

transmitting system is limited. In this case, the interference can be avoided through

isolation.

This problem also exists in the 450MHz CDMA system, the interference can be

avoided only after eliminating the overlapped signals. To the case that the systems

possess similar frequency bands, the interference also occurs since the out-of-band

suppressing ability of the transmit system is limited, we can reduce the interference

strength through separation.

In terms of the system whose receiving frequency band is close to the CDMA’s,

CDMA system has a great chance to interfere in the other system’s signal receiving, for

example, 800-MHz CDMA system may affect 900-MHz GSM system. On the other

hand, a system whose transmitting frequency is close to the CDMA’s reverse receiving

frequency band may affect the receiving function of the CDMA system (the bottom

noise level is raised), for example, 1.9-GHz CDMA system may be affected by 1.8-

GHz GSM system.

If the CDMA system needs to share a site with GSM network, it is necessary to reduce

the interference by taking all kinds of seperating methods. Signal intensity of receiving

signal=transmitting power+gain at transmitting end+gain at receiving end-path loss.

5


Try to minimum the value of (gain at transmitting end+ gain at receiving end ); to an

antenna, the gains of its upper, lower, and back lobes are relatively small, so it is better

to make the antennas of the two systems be up and down respectively or make them in

the same plane. If the two antennas are in the upper and lower parts of the pole

simultaneously, considering that an antenna will always have a downtilt, try to set the

antenna at the lower part of the pole, thus antenna downtilt can reduce the interference.

To one 1.9-GHz CDMA system and one 1.8-GHz system, the mutual interference can

be solved through horizontal or vertical isolation. However, as the out-of-band

suppressing capability of the GSM system is unknown, we can not calculate the

specific isolation distance.

Likewise, horizontal or vertical isolation can also be used to reduce the interference

between 800-MHz CDMA system and 900-MHz GSM system.

Besides, to one CDMA system, it should also be taken into account of the isolation

between CDMA and other wireless equipment whose frequency is close to the CDMA

system. The base station should not be set near the devices such as large power station,

paging and microwave devices with similar frequencies.

Specific isolation requirements can only be worked out after information incluing

frequenchy points, out-of-band suppressing capability, etc. has been obtained.

四.4 Planned sites survey and selection

The requirements for planned sites are:

1. There should no apparent obstruction in front of a sector, make sure the planned

direction is available;

2. The antenna height must be 10m~15m higher than ambient buiding for urban

sites, as to suburb and village, the antenna height must be 15m higher than

ambient buiding; the buiding height must not be 1.3 multiple higher than the

planned site height.

3. Select sites with no co-interference, avoid affecting other sites.

4. The distance between the site position and the planned site should not go

beyond 1/4 coverage.

5. GPS solid angle must not less than 90 degree.

6


6. There is enough position for antenna installation on top of building and tower.

7. The equipment room is available.

四.4.1 No Serious Obstruction in front of a Site

Obstruction can affect the coverage greatly as follows: A shade area tends to form

behind the obstacle, and it is difficult to cover this area. Reflections to the signals tend

to occur, thus affecting the coverage of the reverse direction and leading to problems

such as pilot pollution.

Make sure to provide suitable installation position for antenna on the planned site,

there are no serious obstruction in main lobe direction. The site sector direction setting

plays a great influence on coverage of the area around and other sites setting. One site

change will cause other sites adjustment; make sure that the site direction during

planning can be realized in practical environment.

四.4.2 Requirements of site height

For the macro cell, the hanging height of antenna is required to exceed the average

height of the surrounding buildings. The height varies with different environments.

For a better effect, the antenna on a city site should be 10 to 15 meters higher than the

average height of the surrounding buildings (10 m in dense urban and more than 15 m

in suburban and rural areas). The hanging height of the antenna depends on the

coverage range. The height of the candidate site shall not exceed 1.3 times the hanging

height of the planned antenna; otherwise, the coverage range is too big.

四.4.3 Distance requirement of candidate sites and planned sites

The space between the candidate site and the site under being planned should be no

more than 1/4 of the coverage radius.

For the requirements that cannot be met, adjustment can be made based on the existing

conditions. For example, an iron tower, a height enhancement rack, or a long pole can

be built to increase the height. If there is an obstacle in some direction, no sector can be

set in that direction, as long as the topology is not affected.

7


四.5 Planning Ultra-far Coverage BS

When planning an ultra-far coverage BS it needs to try to avoid the BS’s effect on

original networks as much as possible. During the selection of the BS site and

antennas, this requirement should be complied with first.

The main steps for Ultra-far coverage planning are:

1. Know the requirements, including the coverage etc.

2. According to the coverage requirement, the antenna hanging height should

reach the particular value.

3. Simulatin and testing of the planned area.

4. Network topology design according to coverage, antena height etc., base on

electrical map, including site position, direction, antenna parameters,

considering the pilot pollution.

5. Site survey, chose a suitable site. The site should meets the requirements of

height and direction, affects the existing network as less as possible.

6. Suvey the unsuitable sites again according to simulation results.

四.6 Marks correspond to different sites

Table 4-17 shows the marks correspond to different sites.

Table 4-17 Marks correspond to different sites

Site type Classification Description Carrier

number

Sector

number

Macro-

BTS

Micro-

BTS

Ultra-far

Coverage

BS

RFS

O1 O1One carrier omni-

direction1 1 1 0 0 0

S1 O1One carrier one

sector1 1 1 0 0 0

S11 S11One carrier two

sectors1 2 1 0 0 0

S111 S111One carrier three

sectors1 3 1 0 0 0

O2 O2 Two carrier omni- 2 1 1 0 0 0

8



number

Sector

number

Macro-

BTS

Micro-

BTS

Ultra-far

Coverage

BS

RFS

direction

S2 O2Two carrier one

sector2 1 1 0 0 0

S22 S22Two carrier two

sectors2 2 1 0 0 0

S222 S222Two carrier three

sectors2 3 1 0 0 0

O3 O3Three carrier

omni-direction3 1 1 0 0 0

S3 O3Three carrier one

sector3 1 1 0 0 0

S33 S33Three carrier two

sectors3 2 1 0 0 0

S333 S333Three carrier three

sectors3 3 1 0 0 0

O4 O4Four carrier omni-


S4 O4Four carrier one

sector4 1 1 0 0 0

S44 S44Four carrier two

sectors4 2 1 0 0 0

S444 S444Four carrier three

sectors4 3 1 0 0 0

O-L0-R1 O1RFS omni-


S-L0-R1 S1 RFS one sector 1 1 1 0 0 1

S-L0-R2 S11 RFS two sectors 1 2 1 0 0 1

S-L0-R3 S111 RFS three sectors 1 3 1 0 0 1

S-L1-R1 S11Local one sector

RFS one sector1 2 1 0 0 1

S-L1-R2 S111Local one sector

RFS two sectors1 3 1 0 0 2

S-L1-R3 S-L1-R3Local one sector

RFS three sectors2 4 1 0 0 3

S-L2-R1 S111Local two sectors


9



number

Sector

number

Macro-

BTS

Micro-

BTS

Ultra-far

Coverage

BS

RFS

S-L2-R2 S-L2-R2Local two sectors


S-L2-R3 S-L2-R3Local two sectors


S-L3-R1 S-L3-R1Local three sectors






M1 M1One carrier Micro-

BTS1 1 0 1 0 0

M-L1-R1 M11

One Micro-

BTS+one RFS:

one carrier two

sectors

1 2 0 1 0 1

M-L1-R2 M111

Micro-BTS one

sector +RFE two

sectors

1 3 0 1 0 1

M2 M2Micro-BTS two

carriers one sector2 1 0 1 0 0

M3 M3Micro-BTS three

carriers one sector3 1 0 1 0 0

M1804 M140One carrier Ultra-

far Coverage BTS1 1 0 0 1 0

M804-

L1-R1M1140

One carrier Ultra-

far Coverage BTS

+one RFS: one

carrier two sectors

1 2 0 0 1 1

M804-

L1-R2M11140

Ultra-far Coverage

BTS one sector+

RFS two sectors

1 3 0 0 1 1

M2804 M240

Ultra-far Coverage

BTS two carrier

one sector

2 1 0 0 1 0

M3804 M340Ultra-far Coverage

BTS three 3 1 0 0 1 0

10



number

Sector

number

Macro-

BTS

Micro-

BTS

Ultra-far

Coverage

BS

RFS

carrierone sector

11

五 Repeater Planning

Keypoint

Familiar with repeater planning

五.1 Overview of Repeater

In CDMA networks, for ensuring the network performance and meeting the coverage

requirement, besides to the main devices such as base station, repeaters are probably

also needed.

Repeater is in fact a device for signal repeating. In the wireless telecommunications

system, for the cost-saving purpose, apply the wireless repeater to extend the coverage

of the source base station. In the forward link, the repeater accepts the signal from the

donor base station, and then transmits the signal again after amplifying it; in the reverse

link, the repeater antenna receives the signal from the mobile station, and transmits the

signal to the donor base station after amplifying the signal.

Being used in the CDMA network, the repeater can truck the radio signal, expand the

signal coverage, assist transmitting signals to the special environment, adjust the traffic

and eliminate blind areas. The purpose of repeater applying is to cost-effectively widen

the coverage and optimize the network.

Different from the base station, without base band processing circuit and the ability of

demodulating the radio signal, the function of the repeater are only two-way trucking

and amplifying the radio signal. So repeaters are used for the purpose of broadening the

signal coverage and improving the coverage performance, but they can not increase the

network capacity.

Figure 5-13 illustrates the coverage situation of the repeater.

1

Figure 5-13 Coverage of repeater

In practice, the base station in which the repeater is located is named donor base

station. The wireless link between the donor base station and the repeater is called the

donor link. The repeater antenna which receives the signal from the donor base station

is donor antenna, and the repeater antenna which faces the user is named the repeater

antenna.

The application of the repeater to the CDMA network will cause changes in the

network topological structure, link budget, noise, time delay and multi-path

information. These changes will exert great influence on the cell coverage, handoff

relation, uplink/downlink power budget, cell subscriber capacity and system

parameters, and so on.

The repeater has a direct influence on the donor base station. It expands the coverage

of the donor base station and increases its traffic. As the repeater itself produces noise,

it will affect the floor noise of the donor base station to a more or less degree based on

the gain, and finally result in the coverage radius decrease of the donor base station and

the transmitting power increase of the mobile station in the coverage area. If the

repeater cannot well ensure the diversity effect, it will also directly influence the

capacity of the base station.

Another problem which should be considered during the network planning is the

influence on surrounding base stations caused by the repeater. The repeater appears as

a noise source for surrounding base stations and will affect both the coverage and

capacity of them. When the repeater is introduced into the system, the network

coverage situation changes, so does the voice traffic loaded by all base stations. The

2

5 Repeater Planning

repeater will “absorb” part of the traffic from surrounding base stations. If the voice

traffic of surrounding base stations is busy, the repeater can play a role of balancing the

system traffic, and make a maximum use of the system processing capability.

In the mixed repeater networking technology, it requires to treat the repeater as a

network element similar to a base station. During the stages of network planning,

engineering and optimizing, the mutual relationship between the base station and

repeater should be considered thoroughly from the angle of the system. Besides, the

uplink and downlink coverage, interference, noise and system parameter setting should

be evaluated and calculated, so that the base station and the repeater can together

implement well the wireless coverage and improve the comprehensive network quality.

In this process, the repeater should be treated as a special base station rather than only

as a tool for network optimization. The mixed networking technology involves a series

of practical engineering technologies applied to repeater planning, project installation

and debugging as well as system parameter optimization.

Due to the difference in application, different factors should be considered during the

outdoor repeater project from those for indoor distribution system. Generally speaking,

the outdoor repeater will exert greater influence on the system.

五.2 Repeater Networking and Planning

Network planning and designing is an important part in the construction of a mobile

communication network. It will exert important influence on the network construction

cost and the operation quality of the established network. Mixed networking is

intended to build a mobile communication network of high class of service that can

meet near future and long-term traffic demands with the lowest possible cost.

Specifically, wireless coverage of maximum time and space should be implemented in

the service area and the required communication probability should be met; the

interference should be minimized to meet the required Quality of Service (QoS);

besides, the number of system equipment units should be reduced to the possible extent

to lower the cost on the condition that the capacity requirement can be met.

Traditionally the metropolitan area with densest population is selected as the original

point. Next the radius of the cell can be determined according to the local traffic

density and a base station is used to cover the central population area. The network can

then be expanded on the base of cellular structure. Generally speaking, on the condition

3


that the cellular structure is met, the planned coverage of the base station is directly

related to the local traffic density. That is, for areas with relatively low traffic density,

e.g. sparse urban area, suburb and areas along highways, the planned base station

coverage will be much larger than the coverage in the metropolitan area. This is true

theoretically. However, in practice, due to the topographical factors, the coverage of the

base station often cannot reach the required standard. This wastes the base station

capacity and lowers the equipment utility.

In this case, in addition to the base station, the repeater can be used to help implement

the coverage. Suppose that the capacity is not a limiting factor at the early network

development stage, and then the coverage expansion can improve the equipment utility.

For example, a repeater can be used to extend the base station coverage along the

expressway and expand the capacity. This design can improve the economic benefit of

the network with a small sum of investment.

The mixed repeater networking in the CDMA network can lower the cost and improve

the economic benefit. Its application in foreign countries shows that it can save

30%~40% of the system construction and maintenance investment when it is applied in

the network building in open areas such as suburb, country and expressway, etc.

五.2.1 Features of Repeater Networking

The base station provides the network with capacity and is the core of the network. It is

generally used to cover areas with dense traffic such as urban areas and nearby

suburbs.

The terrain and clutter of cities is complicated. Therefore repeaters are inappropriate

(except for indoor coverage) for reducing interference. Besides, metropolitan areas of

dense population have a great potential for user development; if repeaters are used, as

they cannot provide capacity, base station congestion may occur due to the increase of

user amount.

In sparse urban area, suburb, county, town and areas along highway/railway that

feature less population, repeaters can be used for mixed networking. They can be

configured with omni-directional, directional or multi-directional antennas.

One donor base station can be connected with several repeaters. The number of

repeaters to be configured depends mainly upon the influence of the repeaters on the

ROT of the donor base station.

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5 Repeater Planning

The repeaters can be cascaded at one level at most. The cascaded repeaters feature poor

performance and are not recommended unless necessarily.

五.2.2 Analysis of Noise Introduced by Repeaters

1. Downlink noise

In most applications, the downlink signals reaching the repeaters still feature

high signal-noise ratio and the signal level is much higher than the Gaussian

environment noise. After the signals are amplified by the repeaters (considering

the noise coefficient of the repeaters), the signal-noise ratio is still high and will

hardly affect the system. For example: suppose the working rate is 9.6K and the

downlink noise coefficient of the repeater is 5dB. As the donor link of the RF

repeater requires line-of-sight connection, the signal strength at the input end of

the repeater should be greater than -80dBm and the level of the Gaussian

environment noise should be -113dBm and S/N=33dB. After the signals are

amplified, the signal-noise ratio output by the repeater still reaches 28dB and

meets the requirement.

From the above example, it can be seen that the downlink noise coefficient of

the repeater is generally less than 5dB. Thus, the repeater has little influence on

the system, which can be omitted in practice.

2. Uplink noise

(1) The influence of uplink noise on the thermal noise of the base station

First the uplink noise will cause the level of the thermal noise of the base

station to rise: The repeater is functionally equivalent to an interference source.

Even if there is no user in the covered area, i.e. there is no input on the uplink,

it will also produce interference noise to the base station and cause the thermal

noise level of the base station to rise. This means that the sensitivity of the base

station receiver will decline and all users in the coverage of this base station

will be affected (the users in the repeater coverage will not be directly affected).

The influence of this noise can be seen from the calculation and analysis below:

First, after the repeater thermal noise is amplified, undergoes the loss over the

transmission path and reaches the input end of the base station receiver, its level

can be calculated out:

5


Prep_inject = KTB+Frep_reverse+Grep_reverse-PLnet

In the above formula:

K Boltzmann constant, the truth value of which is 1.38E-23J/K;

T Environment temperature, which is set to 290K;

B Bandwidth, which is set to 1.23MHz;

Frep_reverse Uplink noise coefficient of the repeater;

Grep_reverse Uplink gain of the repeater.

PLnet The net value of the path loss from the repeater to the

base station, including the repeater feeder loss, donor antenna gain of the

repeater, path loss, base station antenna gain and base station feeder loss

In this case, the equivalent thermal noise level at the input end of the base

station receiver is:

Pbts_noise_floor = KTB+Fbts_receiver

Thus, level rise of the base station thermal noise ROTrep (Rise Over Thermal) is:

The introduced Noise Injection Margin (NIM) is:

This value determines the influence of the repeater on the uplink of the donor

base station. Every 1dB of NIM is increased; the uplink power budget of the

donor base station or the allowed special path loss from the mobile phone to the

base station will decrease for 1dB. In terms of the cell coverage, the uplink

coverage radius will decrease; for the users in the coverage, the transmitting

power of the mobile phone will increase accordingly, or the users on the cell

edge will suffer from such phenomena as monolog, decline of uplink voice

quality or call drop.

From the above analysis, it can be seen that once the location of the repeater

and base station is determined, the noise level from the repeater to the base

station receiver depends entirely on the setting of the reverse gain while it is

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5 Repeater Planning

independent of the repeater noise coefficient and the pass loss. Thus, in practice

the uplink gain of the repeater can be adjusted to reduce its influence on the

base station.

The following figure shows the relation between NIM and the rise of the

thermal noise level caused by the repeater:

Figure 5-14 Relation between NIM and thermal noise level rise caused by repeater

(2) Influence of the uplink noise on the repeater coverage

A repeater in wireless connection with the donor base station is equivalent to a

cascaded amplifier (as shown in Figure 5-15). The influence on the users in the

repeater coverage can be measured through the cascading noise coefficient.

7


Figure 5-15 Equivalent cascaded amplifier

Fcascade = Frep_reverse+(PLnet*Fbts)/Grep_reverse -1/Grep_reverse

≈Frep_reverse+PLnet*Fbts/Grep_reverse

= Frep_reverse*(1+10NIM/10)


The introduced Noise Injection Margin (NIM) is:

NIM=10log(Pbts_niose_floor/Prep_inject)=10log(PLnet*Fbts_recerver/Grep_reverse* Frep_reverse)

Fbts_receiver Noise coefficient of the base station station receiver

Pbts_niose_floor Equivalent noise level at the input port of the base station receiver.

Prep_inject Uplink noise injection level of repeater, equivalent to the input port

of the base station receiver

For a repeater coverage area, when the uplink power budget is considered, the

noise coefficient of base station receiver used for base station uplink power

budget is replaced by the cascading noise coefficient. The cascading noise

coefficient will only affect the users in the repeater coverage. If it increases, the

uplink power budget of the repeater coverage will be influenced and the uplink

coverage radius will reduce.

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5 Repeater Planning

Figure 5-16 Repeater cascading noise coefficient

(3) Compromise solution to the influence caused by the uplink noise

In the planning, the contribution of the repeater to the thermal noise of the base

station should be minimized. As the ROT and NIM are on a relation of inverse

ratio, when the valid gain (Grep_reverse-PLnet) is very small or negative, the greater

the NIM is, the less the ROT as long as the NIM is greater than 0.

On the contrary, when NIM becomes greater, so does the Fcascade. For example:

When NIM=6 and Frep=6dB, ROTrep=1dB, Fcascade=13dB.

When NIM=10 and Frep=6dB, ROTrep=0.4dB, Fcascade=16.4dB.

In practice, a compromise value should be adopted between the two values.

Reference materials and analysis show that in areas such as highway, suburb

and country, the repeater is required to cover a long distance and the Fcascade be

minimized. When NIM=0dB, ROTrep=3dB and Fcascade reaches 8dB, 3dB more

than the uplink noise coefficient of the repeater. In special areas such as

metropolitan indoor coverage, NIM can be set to a greater value. Thus, the

influence of the ROTrep can be reduced as long as the application requirement

can be met.

(4) Repeater influence on the system capacity

9


The repeater’s influence on the system capacity can be considered from two

aspects: the thermal noise produced by the repeater will influence the system

capacity; besides, the requirement for user Eb/Io rise of the repeater coverage

will also influence the system capacity.

The cell capacity depends on the Multiple Access Interference (MAI).

Figure 5-17 Multiple access interference

As shown in the above figure,

When there is no user, the port of the base station receiver has thermal noise

level.

When the first user accesses, he only needs to transmit signals the strength of

which is W/R-Eb/Io lower than the thermal noise voice because of the power

control. W/R here refers to the gain of the spread spectrum; Eb/Io refers to the

rate between the power density of the signal spectrum required by the base

station and the power density of the noise. In this case, the port of the base

station receiver includes thermal noise level+ signal level.

When the second user accesses, he only needs to transmit signals the strength of

which is W/R-Eb/Io lower than the noise level+ signal level of the first user. As

the signals transmitted by the first user are also noises to the second user, the

second user should increase the transmitting power to overcome the

interference from the first user in addition to the interference from the thermal

noise level. Therefore, the noise level rise reflected at the port of the base

station receiver is greater than that when there is only one user, i.e. the level

indicted by the white part of the above figure is greater than the level indicated

10

5 Repeater Planning

by the red part.

When three or more users access, the change follows the same trend as above

and the extra transmitting power to be increased becomes greater and greater.

When the Nth user accesses, as there are many users at that time, the extra

transmitting power to be increased is so high that it becomes impossible to

overcome the interference and implement stable demodulation (in practice, the

case will come earlier as both the transmitting power of the mobile phone and

the system power control capability are limited). This is called the “pole” of the

capacity in the CDMA principles. In this case, the pole capacity of the system is

N-1.

The injection noise caused by the thermal noise of the repeater is static and is

similar to environment interference. From the Figure 5-17, it can be seen that

only the noise level of the base station receiver is increased. This may cause the

increase of the transmitting power of the mobile station or decrease of the

uplink coverage radius, but it will not affect the user capacity because of the

power control of the CDMA system.

If no diversity technology is adopted in the repeater, in order to achevie

satisfying FER, the system will require the user Eb/Io in the repeater’s coverage

to rise to 8dB or more. Thus, the capacity of the donor base station will be

influenced. The specific influence depends on the user amount in the coverage

of the base station. Approximately one user in the repeater coverage is

equivalent to 1.1~1.3 users of the base station. It should be pointed out that in

some repeaters; the other spatial diversity message is delayed and changed into

multi-path signals, which are then combined together. This diversity receiving

method through multi-path receiving increases the processing load of the base

station as it causes multi-path artificially. Thus, in practice, the effect is greatly

lowered.

五.2.3 The Case that Several Repeaters Share One Donor Base Station

Suppose that each repeater will influence the thermal noise rise of the donor base

station. From the above analysis, it can be seen that this influence is related to the

uplink noise coefficient of each repeater, the path loss between each repeater and the

donor base station and the uplink gain of the repeater. The influence on the donor base

11


station equals to the sum of influence of these repeaters. The number of repeaters that

one base station can be connected with should be determined according to the thermal

noise rise of the base station.

If the uplink gain of the outdoor repeater is adjusted to an appropriate value, i.e. it will

only cause the thermal noise of the base station to rise for 3dB, then:

1 repeater ROT=3dB

2 repeaters ROT=4.7dB

3 repeaters ROT=6dB

4 repeaters ROT=7dB



Next, the maximum thermal noise rise that a base station can tolerate should be

considered. Different base stations in the network have different tolerance capabilities.

If the capacity of a base station is limited by the high traffic density in its coverage or

its coverage radius is shortened because of the barriers, then the uplink power budget

will have large redundancy. Thus, the base station will be able to tolerate great thermal

noise rise while its coverage will not be severely affected. Urban indoor coverage

generally allows great cascading noise coefficient. As the uplink gain is small, the

influence on the thermal noise of the base station can even be omitted. Of course, the

coverage of some minor base stations can be sacrificed so that repeaters can be added

to improve the overall coverage effect, e.g. the coverage of highway. In short, after the

repeater’s influence on the thermal noise of the base station is made clear, the number

of repeaters that a base station can be connected with should be determined according

to the specific situation of each base station.

In the above, the capacity of the donor base station is omitted. However, it should be

considered in practice. Therefore, the number of repeaters that can be connected to a

base station should also be determined on the base that the capacity of the donor base

station can meet the user capacity requirement of the base station as well as the

repeater coverage.

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5 Repeater Planning

五.2.4 Repeater Cascading

The ideal mode is that each repeater is directly connected to the donor base station

through links. Thus, it can be ensured that wireless signals of good quality are relayed.

In some special cases such as highway coverage, repeater cascading is better for

implementing the coverage. The application of repeater cascading should also start

with noise analysis. The bottleneck still lies in the thermal noise rise of the base station

and the cascading noise coefficient.

Figure 5-18 Equivalent model of repeater cascading

To set up the equivalent model of repeater cascading, calculate as follows:

Thermal noise injection

Prep_inject =KTB+NF1+(G1-PL1)+ NF2+(G1-PL1)

Cascading noise coefficient Fcascade

=NF1+(NF2-1)/(G1-PL1)+(NF3-1)/(G1-PL1)(G2-PL2)

It is known that the injected thermal noise is in direct ratio with the repeater gain and in

reverse ratio with cascading noise coefficient. Suppose the noise coefficient of the

repeater and the base station is 5dB, through the model, it can be known that:

When the thermal noise rises for 3dB, the cascading noise coefficient is 5dB than the

noise coefficient of the base station.

From the above calculation, it can be seen that when the repeater cascading is applied,

the conflict between cascading noise coefficient in the repeater coverage at the second

level and the thermal noise rise of the base station will become acute. Thus, in the

application the performance will be greatly affected. However, with well planning and

delicate project optimization, the two-level repeater cascading can be applied to some

13


special cases. Due to the influence of cascading noise coefficient and the thermal noise

rise of the base station, repeater cascading of three or more levels has little practical

significance and therefore is not recommended.

五.2.5 Donor Link of Repeater

It is simple to select the donor link for an optical repeater. However, the selection of a

good donor link for a radio frequency repeater is critical.

First, the donor antenna of the repeater should be in the Line Of Sight (LOS) relation

with the antenna of the donor base station. As radio waves at the ultrashort wave and

microwave band have high frequency, when they are propagated along the ground, the

fading is great and their diffracting ability is weak when barriers are met. Therefore,

the propagation through ground waves cannot be used. Besides, as the altitude

ionization layer cannot reflect the radio waves to the ground, the propagation through

air waves cannot be used either. Generally the LOS propagation mode is used. In

mobile communication, generally the radius of wireless cell is limited to tens of

kilometers. Therefore, LOS and near-LOS propagation mode are considered. The

outer-LOS diffraction is used in the fixed radio communication. During the project

planning and designing, the model suitable for the environment is selected to design

the radio circuit based on the study of the radio wave propagation.

Figure 5-19 Free space propagation

In the space between the transmitting and receiving antennas through which the radio

waves are propagated, there is space area that plays a major role for energy

transmission. If this area meets the conditions for free space propagation, then the radio

14

5 Repeater Planning

waves can be considered as being transmitted through free space. According to the

Huygens-Fresnel principle, in the first Fresnel area, the radiation field strength

produced at the signal receiving point is two times of the field strength in the free space

propagation. To make the field strength at the receiving point equal to the field strength

in free space propagation, only 1/3 of the first Fresnel area needs to be used. This area

is called minimum Fresnel area, the radius of which is 0.577 times of the radius of the

first Fresnel area. In engineering, usually the first Fresnel area and the minimum

Fresnel area are considered as the space that plays the major role for radio wave

propagation and are referred to as major propagation area.

In engineering, it is required that the donor antenna of the repeater is on a LOS relation

with antenna of donor base station. Generally both of them can meet the requirement of

major propagation area. Therefore, the path loss of the donor link is generally

calculated through the free propagation formula:

fDPL lg20lg204.32

In the formula, D indicates the space distance and the unit is km, while f indicates the

working frequency and the unit is MHz.

Suppose that the base station feeder loss ILbts_cable=3dB, the repeater feeder loss

ILrep_cable=3dB, the base station antenna gain Gbts_antenna=14dBi and the repeater donor

antenna gain Grep_donor _antenna=18dBi. Then, through calculation the following table can

be obtained, which can be used for general evaluation of the donor link.

Table 5-18 Example of calculating path loss

Donor Link Distance 1km 5km 10km 15km 20km 25km 30km

Free space path loss Lp 91.0 105.0 111.0 114.6 117.1 119.0 120.6

Net path loss PLnet 65.0 79.0 85.0 88.6 91.1 93.0 94.6

Next, the signal strength from the donor base station to the repeater should be greater

than -80dBm, so that the stability of the signals relayed by the repeater and the high

signal-noise ratio can be ensured.

Besides, it should also be ensured that the repeater donor antenna only receives the

signals from one cell and the repeater should not be located between at the border of

two sectors. The donor antenna can be used to select more directional parabolic

antenna, so that the spatial selectivity of the radio signals can be enhanced.

15


Last, when the above measures still cannot meet the requirements, horizontal (or

vertical) polarization antenna can be adopted for the donor base station. For stations

that may cause pilot pollution, orthogonal polarization antennas can be adopted, while

antennas with the same polarization as than of the donor base station can be adopted as

donor antennas. Thus, the polarization of the antenna is used to improve the selectivity

of the signals.

五.2.6 Antenna Feeder System

1. Donor antenna selection

Yagi antenna, corner-reflector antenna, plate antenna or parabolic antenna can

be adopted as the donor antenna. The choice depends on the pilot strength and

pilot interference strength of the donor base station at the installation place.

Generally the donor antenna can be selected according to the following

standard:

(1) When the pilot strength is high and the interference is weak, Yagi antenna,

corner-reflector antenna or plate antenna can be adopted;

(2) When the pilot strength is high and the interference is strong, Yagi antenna or

parabolic antenna can be adopted;

(3) When the pilot strength is low and the interference is strong, parabolic antenna

can be adopted;

(4) Generally 1.2m grid parabolic antenna or Yagi antenna can be adopted as donor

antenna. Depending on the specific condition, sometimes plate antenna can also

be adopted.

Technical indices of 1.2m grid parabolic antenna:

Working frequency band: 824-894MHz

Gain: >18dBi

Front-to-back ratio: >25dB

3dB beam width: <200

Standing wave ratio: <1.5

Wind resistance (m/s): >50

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5 Repeater Planning

Lightning protection: direct grounding

Connector: N type

The antenna has a ± 10o adjustable range in the direction plane and pitch plane.

Technical indices of Yagi antenna:

Working frequency band: 824-894MHz

Gain: >11dBi

3dB beam width: <400

Standing wave ratio: <1.5

Wind resistance (m/s): >50

Lightning protection: direct grounding

Connector: N type

The antenna has a ± 10° adjustable range in the direction plane and pitch plane.

2. Forwarding antenna selection

Generally omni-directional and plate antennas (45 o, 65 o, 90 o and 120 o) that

are the same as the CDMA base station antenna are adopted.

3. Feeder

Feeder cables 7/8"+1/2" that are similar to CDMA base station feeders can be

adopted as the feeders of the repeater. The feeder can also consist only of 1/2"

or other feeder cables for the installation convenience when the planning

allows. Example:

Table 5-19 Repeater feeder

Model Impedance Hectometer Loss 800M Outer Diameter

1/2" 50 ohm 6.3dB 13.2mm

SYWV-50-12 50 ohm 8.2dB 15.6mm

Fast Estimation of Repeater Coverage

The procedures for estimating the repeater coverage are the same as those for

estimating the base station coverage. The repeater coverage mainly depends on the

17


propagation loss from the repeater to the mobile phone and the maximum permitted by

the system. In addition, the human body loss margin, building penetration loss margin

and fading loss margin should also be taken into consideration. The major difference

lies in the reverse link power budget. Here, the original noise coefficient of the base

station receiver is replaced by the repeater cascading noise coefficient.

The major parameters that influence the repeater coverage include the antenna type,

height, downtilt, topographical parameter, required Ec/Io value, transmitting power and

gain. Here a group of empirical values are provided for fast and convenient estimation.

First consider the propagation loss. The Okumura-Hata model is adopted here to

analyze the radio propagation of 800MHz CDMA system.

PL(dB)=69.55+26.16log(F)-13.82log(H)+(44.9-6.55log(H))*log(D)+C


PL: indicating pass loss in dB

F: frequency in MHz (150-1500MHz); 800MHz for calculation

D: distance in km

H: valid height of the base station antenna in m; 40m for calculation

C: environment correction factor, metropolitan area: 0 dB; urban area: -5 dB

Suburb: -10 dB; Country: -17dB

Then, the maximum permitted path loss can be calculated out with reference of the

uplink/downlink power budget of the system.

At last, the maximum permitted path loss can be introduced into the formula to

calculate the repeater coverage radius.

According to the above formula, the relation between the distance and path loss can be

worked out, as shown in Table 5-20:

Table 5-20 Relation between distance and path loss

d_1 Metropolitan Area Urban Area Suburb Open Land

1 123.4 123.3 113.7 95.3

1.5 129.4 129.4 119.8 101.4

2 133.7 133.7 124.1 105.7

2.5 137.1 137.0 127.4 109.0

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5 Repeater Planning

d_1 Metropolitan Area Urban Area Suburb Open Land

3 139.8 139.8 130.1 111.7

3.5 142.1 142.1 132.4 114.0

4 144.1 144.1 134.4 116.0

4.5 145.8 145.8 136.2 117.8

5 147.4 147.4 137.8 119.4

5.5 148.8 148.8 139.2 120.8

6 150.1 150.1 140.5 122.1

6.5 151.3 151.3 141.7 123.3

7 152.4 152.4 142.8 124.4

7.5 153.5 153.5 143.8 125.4

8 154.4 154.4 144.8 126.4

8.5 155.3 155.3 145.7 127.3

9 156.2 156.2 146.6 128.1

9.5 157.0 157.0 147.4 128.9

10 157.8 157.8 148.1 129.7

10.5 158.5 158.5 148.9 130.4

11 159.2 159.2 149.6 131.1

11.5 159.9 159.8 150.2 131.8

12 160.5 160.5 150.9 132.4

12.5 161.1 161.1 151.5 133.0

13 161.7 161.7 152.0 133.6

13.5 162.3 162.2 152.6 134.2

14 162.8 162.8 153.2 134.7

14.5 163.3 163.3 153.7 135.3

15 163.8 163.8 154.2 135.8

15.5 164.3 164.3 154.7 136.3

16 164.8 164.8 155.1 136.7

16.5 165.2 165.2 155.6 137.2

17 165.7 165.7 156.1 137.6

17.5 166.1 166.1 156.5 138.1

18 166.5 166.5 156.9 138.5

18.5 167.0 166.9 157.3 138.9

19 167.4 167.3 157.7 139.3

19.5 167.7 167.7 158.1 139.7

20 168.1 168.1 158.5 140.1

20.5 168.5 168.5 158.9 140.4

19


五.2.7 Isolation

If the donor antenna of the CDMA repeater is poorly isolated from the re-transmitting

antenna, then the spontaneous emission of the repeater system will occur. In practice, a

margin of 10~15dB is required between the repeater gain and its isolation. The latter

directly restricts the former.

1. Calculation and Empirical Estimation of Isolation

Theoretically, the antenna isolation can be calculated through the following

formula (in the unit of dB):

ISO=PLs+Lcable+Lo-Grep_sub+ADd-Grep_donor+ADr+XPD


ISO: antenna isolation (dB value)

PLs: inter-antenna signal transmission fading value

PLs=-27dB+201gF+201gD

F: frequency, in the unit of MHz

D: the distance between two antennas, in the unit of meter

Lcable: overall feeder loss

Lo: barrier loss, e.g. , due to buildings and shielding grid

Grep_sub: forwarding antenna gain of the repeater

ADd: angle discriminating value between the retransmitting antenna and the

donor antenna, determined by the direction pattern of the retransmitting antenna

Grep_donor: donor antenna gain

ADr: angle discriminating value between the retransmitting antenna and the

donor antenna, determined

by the direction pattern of the donor antenna

XPD: polarization angle discriminating value between two antennas (not used

in most mobile communication systems)

The practice, the above formula can be simplified. The Figure 7-14 shows a

repeater antenna installed on a building.

20

5 Repeater Planning

Figure 5-14 Installation of repeater antennas

The factors that affecting the antenna isolation are also shown:

In the above figure:

F/Bdonor: the front-to-back ratio of the repeater donor antenna

Lwall: loss caused by barrier

F/Bsub: the front-to-back ratio of the repeater forwarding antenna

PL: space loss, measured on the base of the free space propagation loss

From the above formula, it can be seen that major factors that influence

isolation between the donor antenna of the repeater and its retransmitting

antenna include:

(1) The front-to-back ratio of the antenna: it is mainly determined by the antenna

type. For parabolic donor antennas that are commonly used, however, some

measures can be adopted to increase the front-to-back ratio. For example, metal

cylinder surrounding can effectively suppress the wide-angle minor lobe and

back lobe.

(2) The space propagation loss caused by the distance between the donor antenna

and retransmitting antenna: it is closely related to the distance between the two

antennas. The greater the distance is, the greater the attenuation. For example,

21


the attenuation for a distance of 30m is 20dB than that for a distance of 3m. In

addition, the increase of the distance also makes the system more complicated

and increases the loss and the cost. Table 5-21 shows the relation between some

distances and the space propagation loss (f= 850MHz).

Table 5-21 Relation between antenna distance and space propagation loss

Distance between two Antennas (m) Space Propagation Loss (dB)

3 41.4

5 44.87

10 50.89

20 56.91

30 60.43

50 64.87

(3) Fading caused by natural or artificial barrier between the donor antenna and

retransmitting antenna: the isolation can be increased by barriers between the

donor antenna and retransmitting antenna, such as buildings, which are difficult

to be damaged and do not increase the cost. They are good choices in some

environments.

(4) Isolation problem caused by environment reflection: as well the height

difference between the two antennas. Sometimes the repeater may be located in

a complicated environment where large reflector exists. The energy radiated by

an antenna is reflected and then passes the main lobe, side lobe or back lobe of

another antenna. When this energy is equal to or even greater than the energy

received by the back lobes of the two antennas, then it will become an

important source of interference. This requires that a building or tower as high

as possible should be selected as the site for installing the repeater antenna. In

addition, there should be no large reflector near the radiation area of the main

lobe or large minor lobe. Reflections that are difficult to avoid can be isolated

by shielding net or other barriers in the environment through the selection of

appropriate position for locating the donor antenna.

(5) Installation Height difference between two antennas: this height difference

increases the physical distance between the two antennas and facilitates the

adding of barriers in-between.

22

5 Repeater Planning

(6) In the case that the isolation is inadequate but surrounding barriers cannot be

used, some barriers such as shielding net can be added manually to increase the

isolation.

2. Engineering measurement of isolation

In the engineering, the isolation is the major factor that affects the smooth

activation of the repeater. It is also the one that is difficult to be predicted. Great

error may occur during the empirical estimation and calculation so that the

repeater can not be activated according to parameters set in the plan. The most

accurate method is to directly measure the isolation, which, though

troublesome, it is the best. If the gain of the planned repeater is required to be

high, then the isolation should be measured when it is possible.

Below, we will take the repeater in 800 MHz as an example and introduce the

measurement of the repearter isolation.

Instrument: portable spectrum analyzer, signal generator

Measurement tools: donor antenna, forwarding antenna and feeders

Measuring procedures: set the frequency of the RF signal source to be output at

833.49MHz single tone and set the output power to 10dBm (fixed amplitude

power). Turn on the spectrum analyzer and the radio frequency switch, and then

record the receiving power P0 of the spectrum analyzer at 833.49MHz. The

difference between them indicates the isolation of the uplink antenna. Connect

the feeder of the forwarding antenna to the RF signal source and the feeder of

the donor antenna to the spectrum analyzer. Then set the frequency of the RF

signal source to be output at 878.49MHz signal tone and set the output power to

10dBm (fixed amplitude power). Turn on the spectrum analyzer and the RF

switch, and then record the receiving power P0 of the spectrum analyzer at

878.49MHz. The difference between them indicates the isolation of the

downlink antenna.

23


Figure 5-15 Isolation-measuring equipment

3. Shielding Net

In the case that the isolation is inadequate but surrounding barriers cannot be

used, some barriers such as shielding net can be added manually to increase the

isolation. Generally zinc-coated steel net or aluminum net is adopted as the

shielding net and the grid can be set to 0.1-0.25λ. The aperture of the grid for

shielding 800MHz signals can be set to 4mm-10mm. The grid is made of

finished zinc-coated steel net or aluminum net plus support rolled angle. Its area

is generally 3-6m2 and is installed near the forwarding antenna. The size and

spacing of the shielding net can be controlled according to the isolation

requirement and the polarization of the antenna. Generally the spacing in the

polarization direction (linear polarization) should be less than 1/10 of the

wavelength. In the cross polarization direction, the grid can be much sparser. In

addition, the isolating net should be well grounded.

4. Setting of Repeater Parameters

The gains of the forward and reverse links are the major indices of the repeater.

On the condition that the original network performance is ensured, the

forward/reverse gain of the repeater can be adjusted to implement the expected

coverage, so that the balance can be kept between the forward and reverse links

of the traffic channel in the repeater’s coverage.

24

5 Repeater Planning

In the above noise analysis, we have already known the best setting of the

uplink gain of the repeater. Naturally, this setting is not suitable for all cases.

The specific setting should be based on the parameters in the mixed repeater

networking plan. Here the example is only used to illustrate the repeater gain

setting during the installation of the project.

First, measure the net path loss from the donor antenna port of the repeater to

the receiver port of the base station. Connect the measuring devices as shown in

Figure 7-16. Then, the signal generator generates signals of appropriate power,

while the spectrum analyzer measures the received signal strength. The

difference between the two values is the net path loss Plnet.

Next, calculate the uplink gain of the repeater on the base of the noise analysis.

Suppose:

That the maximum noise tolerance allowed by the donor base station is M;

That the noise coefficient of the donor base station is NFbts;

That the noise coefficient of the repeater is Nfrepeater;

That the path loss from the repeater to the base station.

Then, the reverse link gain of the repeater is:

Greverse=PL+NFbts-NFrepeater-M

At last, adjust the uplink gain of the repeater to Grep_reverse. The downlink gain

can also be set to Grep_reverse and can be adjusted according to the specific

situation as long as it does not exceed the maximum downlink power. Thus, the

repeater is set.

25

六 Principles for PN Planning and Setting of Initial Neighboringing Cell

Keypoint

PN planning procedure, setting of initial neighboringing cell

六.1 Overview

Whether the PN planning and initial neighboringing cell setting are reasonable affect

network performance greatly, unreasonable PN planning may result in lack of PN

multiplexing distance then cause interference, unreasonable neighboringing cell setting

may result in voice quality degrade, handoff call drop etc.

Figure 6-20 illustrates the PN planning and initial neighboringing cell setting stage in

network planning flow.

Figure 6-20 Position of radio parameter setting in network planning

The results of PN planning and initial neighboringing cell setting act as the output of

network planning, load to BSC background on site commissioning.

1

六.2 PN Planning

The PN planning follows the completion of the network topology design and the

network simulation. The PILOT-INC is 3 or 4 typically.

The following procedures are recommended:

(1) Decide the Pilot_Inc before determining the pilot set which can be adopted.

(2) Group all BSs according to the number of pilot sets and site distribution. The

number of BSs should not exceed the multiplexing groups of available pilot

sets. Take the multiplexing group of the densest area as the basic multiplexing

group.

(3) Decide the PN multiplexing of every site in the multiplexing group and in the

basic multiplexing group. Correspondence should be formed. Consider the

isolation between the same PN of different multiplexing group, that is, the

multiplexing distance should comply with the requirement.

(4) Starting from the sparsest multiplexing group, assign PN resource for each cell.

The space between the sites in the sparse area is huge, and interference between

adjacent PNs tends to occur. This should be considered as important issue

during the planning.

(5) Based on the PN setting of the multiplexing groups in the sparse area, and the

correspondence between multiplexing groups, get the PN planning of other

multiplexing groups. For the interference that may exist between adjacent PNs

in some multiplexing groups, adjust slightly the PN planning. Or adjust the

multiplexing relationship between different multiplexing groups. Do not to

affect the planning of other multiplexing groups.

(6) Check the planning result through software tool, and adjust slightly the problem

area.

六.2.1 PILOT_INC setting

For the same system, if the delay estimation is not correct, the other pilot may be

demodulated by mistaken, affects the performance of the network. It is necessary to

keep a certain isolation beween different pilots, avoid interference between different

cells due to mids-demodulation of pilots.

2

6 Principles for PN Planning and Setting of Initial Neighboringing Cell

PILOT_INC, one unit corresponding to 64 chips, avoid neighbouring PN_Offset

interference and same PN_Offset interference while planning: in order to avoid

neighbouring PN_Offset interference, it is required that the space of neighbouring

PN_Offset is much greater than the difference due to propagation delay; in order to

avoid same PN_Offset interference, it is required that the difference caused by

propagation delay is greater than half of the pilot search window. Take the two

requirements into consideration; we can derive the reasonable PILOT_INC setting.

The following PILOT_INC setting can satisfy the interference demands basically.

Table 6-22 PILOT_INC typical setting

Dense area theoretical

value

Dense area

Recommended

value

Suburb & village

theoretical value

Suburb & village

Recommended

value

2 4 4 4

3 6 6 6

Recommended value of PILOT_INC is one multiple of theoretical value in dense area:

on the one hand enough PN resource can be reserved for future expansion; on the other

hand, the possibility of interference due to cell propagation delay caused by large

coverage in the beginning of network construction can be decreased. As to suburb and

village, because the site distance is great, the site density is low, there is no problem of

Pilot multiplexing, and the isolation requirements can be obtained by not setting

neighbouring PN to neighbouring sites.

In practical, we can set the PILOT_INC for city and village to the same value. PN is set

discontinuously when a set pilot for city and village, if the PILOT_INC is set to 4 in

system, city PILOT_INC is set to 4, suburb &village PILOT_INC is set to 8, and thus

the requirements for city and suburb are achieved.

In PN planning, two methods can be adopted to set the PN_Offset of each sector of the

same BS after deciding the Pilot_Inc.

1. Continuous setting: the PN_Offset of the three sectors of one BTS are: the first

sector3n+1 × PILOT_INC; the second sector3n+2 × PILOT_INC; the third

sector3n+3 × PILOT_INC;

3


2. Discontinuous setting: the PN_Offset has certain difference for the three sectors

of one BTS and the difference is n×PILOT_INC for the corresponding sector of

different BTS. The PN_Offset of the three sectors of one BTS is set as: the first

sector n × PILOT_INC; the second sector n × PILOT_INC+168; the third

sector n × PILOT_INC+ 336.

In practice, the second way is preferred.

Whatever PN setting methods used, once the PILOT_INC is determined, the PN

resource is certain.

(1) If Pilot_Inc is set as 3, the number of provided resource PN is [512/3] =170.

Each PN group uses three PNs (assuming three sectors for each site). For new

network, half of them remaining for future, the number of usable PN group is

[170/(3*2)]=28. That is, for new network, each multiplexing set can have 28

sites.

(2) If Pilot_Inc is set as 4, the number of provided resource PN is [512/4] =128.

Each PN group uses three PNs (assuming three sectors for each site). For new

network, half of them remaining for future, the number of usable PN group is

[128/(3*2)] = 21. That is, for new network, each multiplexing set can have 21

sites.

六.2.2 Site PN planning

1. First one basic multiplexing set should be determined, and surrounding sites

can be divided into many multiplexing sets basing on this.

2. According to relative location of the sites, we should determine that every site

of different multiplexing sets use the same PN set with which site of the basic

set, avoiding adjacent sites use the same PN set.

3. Determine every site PN planning of the sparsest multiplexing set. Proper

spacing should be adopted by the distance between adjacent sites, in order to

avoid the interference between sites.

4. For the sites with less than 3 sectors, redundant PN resource can be not used.

For the sites with more than 3 sectors, each site uses two continuous PN sets.

4

六.3 Setting of Initial Neighboringing Cell List

After PN is set, the neighboringing cell list should be set. Whether the setting is

reasonable or not will affect the handoff success rate and system performance.

The initial neighboringing cell list during the system design can be set with reference

to the following ways (after the system is formally activate, the neighboringing cell list

can be adjusted according to the statistics of handoff times):

Different cells of the same site must be set as mutually neighboringing cells;

The first layer of neighboringing cells and the second layer of cells should select their

respective neighboringing cells based on the coverage of the site (as shown in Fig. 7-

4). The two layers of cells facing the current sector should be set as neighboringing

cells, while the first layer at the back of cells can also be set as neighboringing cells.

The Figure 6-21 is an example for setting neighboringing cells:

PILOT_INC is actually set to 4 (it can be set to 2 in the system), while the pilot can be

set according to the first method introduced above;

The current cells are in red and their PNs are set to 4, 8 and 12 respectively;

The first layers of cells are in pink, while the second layers are in blue.

5


Figure 6-21 Example for setting neighboringing cell list

The neighboringing cells of the current cells can be set as follows:

Table 6-23 Example for setting neighboringing cell list

Sector No. Pilot No. (PN) Neighboringing Cell List

1-1 48, 12, 32, 48, 88, 92, 100, 108, 112, 128, 140, 144, 156, 196, 200, 204,

208, 220

After the neighboringing cells of all sectors are set, it should be checked whether their

neighboringing cells match each other.

6


According to the number of neighboringing cells configured to each cell and mutual

match between them, the neighboringing cells can be adjusted to make them match

better. The number of neighboringing cells cannot exceed 18 and the mutual match rate

of the neighboringing cells should be greater than 90%, which can be inspected

automatically by relevant tools on OMC when the related parameters are being input

into the OMC.

For a service area where there are relatively few sites (less 6), all sectors can be set as

neighboringing cells.

六.4 Setting of Dual Frequency Neighboringing Cells

In the dual carrier system, some base stations are of dual carrier type. The dual carrier

cell neighboringing to the single carrier base station is referred to as critical cell.

The carrier shared by all base stations is called public carrier, while the other is called

second carrier. When a mobile phone is at the second carrier of the critical cell, it may

move toward a neighboringing single carrier base station. As the neighboringing single

carrier base station does not have the second carrier, necessarily the mobile phone will

switch over in the critical cell from the second carrier to the public carrier. IS95 mobile

phone can only search one frequency, therefore the neighboringing single carrier base

station cannot be seen from the second carrier and the mobile phone cannot initiate the

handoff actively. Instead, the base station should order the mobile phone to switch over

through the following algorithm. 1X mobile phone can search the second carrier in

principle.

When a mobile phone enters the critical cell, it is allocated to the service channel of the

second carrier. The base station orders the mobile phone to periodically report the pilot

strength measuring message. If the strength of all active pilots reported is lower than a

specific threshold, the base station will order the mobile phone to switch over to the

public carrier. This threshold is called frequency change semi-soft handoff threshold.

Frequency change handoff in the critical cell includes two modes: hand-down and

handover. Hand-down refers to the switching from the second carrier to the public

carrier within the same critical cell; handover refers to the switching from the second

carrier in the critical cell to the public carrier of the neighboringing single carrier base

station.

7


Frequency change handoff should be implemented in the dual carrier cell adjacent to

the single carrier cell. The database adds the critical cell ID into the r_Carrier_para.

After the valid diversity is updated each time (which means one call or a handoff is

implemented), BSSAP will send the latest valid diversity to the DBS. Only when DBS

confirms that all cells of the valid diversity are critical cells, can the semi-soft handoff

be implemented. In this case, the base station needs to transmit messages such as

PMRO, PPMRO and CFSRQM to the MS to learn about the wireless environment

where the MS is in, so that it can be determined whether or not to implement semi-soft

handoff.

The conditions for implementing the semi-soft handoff are as follows:

1. There is no leg to be added;

2. All legs are in the critical cell;

3. The search window center of all legs in the valid diversity should be >T_RTD;

4. In the valid diversity, the number of legs whose strength exceeds the threshold

T_Drop should be <2;

5. The strength of all PNs in the PSMM should be lower than T_DropSSHO.

The initial neighboringing cells of the dual carrier system should be set according to

the following principles:

1. The principle for setting the neighboringing cells of the first carrier is the same

as that mentioned above;

2. for the central cell of the second carrier (a non-critical cell), the configuration

of its neighboringing cell list is the same as that of the first carrier;

3. The critical cell of the second carrier should be configured with preferred

neighboringing cells for frequency change handoff. These preferred

neighboringing cells can be selected by finding the single carrier cells that have

most frequent handoff relation with the local cell. The number of preferred cells

that can be selected depends on the handoff mode. In the Handdown mode,

only 3 preferred neighboringing cells can be selected and the MS is switched

over to the basic carrier of the local cell and other three preferred cells. In the

Handover mode, 4 preferred neighboringing cells can be selected and the MS is

8


switched over to four cells other than the local cell. Generally the first mode is

selected;

4. Three cells that are closest to the critical cell in geographical position can be

selected, as the initial preferred neighboringing cells of the critical cell. They

can be adjusted according to the handoff situation after formal activation.

六.5 PN planning by use of CNO

The CNO1 PN planning module is used for the PN planning of CDMA wireless

network. The precondition for PN planning is that the system has loaded the CNO1

data or ZRC data files which contain geographic information of BTSs, such as

longitude, latitude, sector orientation, and so on. Consequently, before conducting PN

planning, make sure that the CNO1 or ZRC data files have been loaded by the system.

The PN planning module includes the following major functions, and its main interface

in CNO1 is shown in Figure 6-22.

Conduct the PN planning for the network without PN configuration

Check up the PN reuse status in the network that has been PN- configured

Specify the cells that can reuse the same PN

Specify the cells on which the PN planning is to be performed

Query the information on PN reuse and PN offset

Conduct the PN planning for the BTS that is to be capacity-expanded

9


Figure 6-22 Interface of PN Planning

The function buttons are shown in Table 6-24.

Table 6-24 Toolbar of PN Planning

Button Function

Load CNO1 data

Load ZRC data

Set PN planning parameters

Query PN reuse and PN offset information

Configure PN-reusing BTS

Conduct PN planning

Check up the PN reuse of original BTS

Output PN planning and PN reuse info.

Two PN planning modes for selection

六.5.1 Parameters Setting of PN Planning

Before conducting PN planning and PN reuse check-up, it is necessary to set a series of

planning parameters, including:

10


1. PN_INC: PN increase

2. PN interval: PN interval among the same PN group

3. Group interval: PN interval between two PN groups

4. Reuse distance: Minimum PN reuse distance

5. Reserved Num: spare PN groups reserved for future usage

6. PN setting for boundary cell: for instance, if this parameter is set as 12, it

means that the PN groups that are multiples of 12 will be reserved; if the value

equals 0, it means that there is no restriction on PN setting for the boundary

cell.

7. Cell radius: Cell coverage radius, which is an empirical value.

Click the button and open the parameter setting interface, as shown in Figure 6-23.

Figure 6-23 Parameters Setting of PN Planning

By default, the system has two PN grouping schemes.

1. Scheme 1 is setting PN_INC as 3, PN interval as 168 and PN group interval as

3. The grouping result of this scheme is shown in the following table:

11


Table 6-25 PN grouping scheme 1

PN Group No. PN 1 PN 2 PN 3

1 3 171 339

2 6 174 342

… … … …

56 168 336 504

2. Scheme 2 is setting PN_INC as 4, PN interval as 4 and PN group interval as 12.

The grouping result of this scheme is shown in the following table:

Table 6-26 PN grouping scheme 2

PN Group No. PN 1 PN 2 PN 3

1 4 8 12

2 16 20 24

… … … …

42 496 500 504

The user can also customize the PN grouping. Having finished the setting of PN_INC,

PN interval and PN group interval, it can be viewed the PN grouping and reservation

status by clicking the button. The interface is shown in Figure 6-24.

12


Figure 6-24 PN Grouping And Reservation

After setting the above parameters related to PN grouping, the user can continue to set

other parameters including Min Reuse Distance, Reserved Num (PN groups for

reservation), and Cell Radius.

When parameter setting is finished, click <OK > to save the current parameter values,

or Cancel to abandon the modification to the current setting.

六.5.2 Setting PN-reusing BTSs

Before PN planning, it can be set in advance some BTSs that can reuse same PN even

though the minimum PN reuse distance can not be satisfied.

1. Click the button to set BTSs that can reuse the same PN. The setting

interface is shown like Figure 6-25 .

2. In the left frame, select BTSs that are to be PN-reused, and then click to

add them into the PN-reusing BTS group. Or, select BTSs from the PN-using

BTS list in the right frame and then click to remove them from the group.

13


Figure 6-25 The Setting of PN-reusing BTS

3. Click the button to save the current setting;

4. To delete the previously set BTS under PN reuse, switch to the View Reuse PN

tab and enter its displayed view; then select the item to be deleted, and click

to remove it, as shown in Figure 6-26.

Figure 6-26 The Deletion of PN-reusing BTS

14


六.5.3 Querying PN Reuse and PN Offset Information

For the current network or BTSs that have been PN planned, it can be queried the PN

reuse status of each cell, as well as the situation of PN alias resulting from those

isolated BTSs located on high mountains.

六.5.3.1 Query of PN reuse information

1. Click the button in the main menu to open the interface of PN Using

View, as shown in Figure 6-27.

Figure 6-27 Interface of PN Querying

The interface consists of two tabbed sub-pages. The PN reuse view page can be

used for querying PN reuse distances among the cells that share the same PN

before or after PN planning. As for the cell whose minimum reuse distance has

been set by cell users, it should be highlighted in red font.

2. Make sure the current PN status: is it original or after-planned. For example, if

the PN information being queried is original, select Original from the

15


expandable list of Select PN status; otherwise, select Planned for the planned

PN.

3. Select the queried PN value from the expandable list of the Select PN value

item, and the distance between any two cells that use this PN will be displayed

in the lower table. The querying result is just like Figure 6-28.

Figure 6-28 The Distance between PN-reusing Cells

4. If you want to query the PN reuse status after PN planning, it only needs to

select Planned in the expandable list of Select PN Status item and then follow

the same operations mentioned in the above step. The query result of PN reuse

information is displayed in Figure 6-29.

16


Figure 6-29 the Query of PN Reuse Information after PN Planning

六.5.3.2 Query of PN offset information

In a real network, radio signals transmitted from an isolated BTS that is located on the

high mountain is capable of reaching far areas, which can cause the phenomenon of PN

alias. For example, due to transmission delay, a PN of 3 received by the mobile is

probably misunderstood to be 6. The query interface of PN confusion is shown in

Figure 6-30.

17


Figure 6-30 the Query of PN Confusion

1. In the Figure 38, for querying the PN confusion information of original or

planned BTS, you can select Original or Planned from the expandable list of

Select PN status item and view their query results respectively.

2. Under the Set PN offset item, input the related parameters for querying PN

alias. PN_INC represents PN increment set by the user, and its default value is

the PN_INC set by the user before PN planning. Level represents the level of

PN alias. The PN offset can be calculated by the following formula:

Offset PN = Current PN + PN_INC Level

(Level = [-Level, +Level])

For instance, when examining PN alias of a cell whose PN is 6, if Level value

is selected to be 0, it means PN alias parameters are not configured. If Level

equals 1, it means cells whose PN are 3, 6 or 9 will be examined.

18


3. Selecting the cell to be queried in the left table, the information of cells that

have PN alias with the queried cell will all be listed accordingly in the right

table.

六.5.4 PN Planning

This module provides two types of PN planning modes: manual planning and

automatic planning. The user can click the button to

make a choice.

六.5.4.1 Manual PN Planning

Manual planning means that the user selects one certain BTS from the BTS

information table and then starts PN planning.

1. Choose the Manual Plan Mode in the button.

2. Click to start PN planning.

During the PN planning, the selected BTS is taken as the center, and the

distance between other BTSs and the selected BTS acts as the judging criterion

of planning. The PN planning goes based on the principle of "maximum PN

reuse distance and minimum PN reuse pairs". The planning result will output

the PN of each cell in BTSs, the PN planning result centering the selected BTS

and the PN reuse status of the whole network. The planning process can be seen

in Figure 6-31. Clicking Cancel button can stop planning process.

19


Figure 6-31 Manual PN Planning

3. The manual PN planning result is displayed in the PN plan result page, as

shown in the left frame of Figure 6-32.

Figure 6-32 PN Planning Result

20


4. Meanwhile, the check-up on PN reuse will be done automatically, with the

check result being listed in the right frame of the page. If the right frame

displays blank, it means there is no PN reuse distance that is less than the set

distance value.

5. Click and then choose PN planning result to save the PN planning result

into CSV files.

六.5.4.2 Automatic PN Planning

The idea of automatic PN planning is: firstly, based on the algorithm of manual PN

planning, the automatic PN planning goes by centering BTSs one by one; the minimum

PN reuse distance and pairs of each centered BTS will be listed. Then the user

designates one certain qualified BTS from the result list of automatic PN planning and

conduct a manual PN planning centering this designated BTS, the final PN planning

result can thus be obtained.

1. Select the Auto Plan from the item.

2. Click , and the automatic PN planning will start.

The speed of automatic planning depends on the quantity of BTSs. And the

planning result will be listed by presenting the schemes that conduct the PN

planning respectively centering one of BTSs. The scheme whose minimum PN

reuse distance is less than the set value will be highlighted in red. The scheme

output is just like the Figure 6-33.

21


Figure 6-33 Auto PN Planning Scheme

六.5.5 Checking-up PN Reuse

As the network that has been PN configured or that has been planned, this function can

do the check-up on the network’s PN reuse status. The check-up result is displayed in

the list. The user can examine the PN reuse information by customizing PN reuse

restriction (minimum PN reuse distance):

1. If checking PN reuse status of the current network, please switch to Original

PN information page first.

2. Click the button in the tool bar, the check-up result on PN reuse status will

be listed in the right frame as shown in Figure 6-34.

3. Click and then choosing Original PN reusing or Planned PN reusing will

respectively save the PN reuse check-up result of original or planned PN

situation into CSV file.

22


Figure 6-34 The Result of PN Reuse Check-up

六.5.6 Selection of BTSs to be PN Planned

Before PN planning, the user can exclude some BTSs or some types of BTSs that are

not necessary to be PN planned.

1. In the main interface, select the BTS information tab and enter the sub-

interface. Through checking or non-checking BTSs listed in the left frame, the

user can select the BTSs not to be PN planned. Alternatively, the user can right-

click in the list of BTSs and then select from the pop-up menu which types of

BTSs are not to be PN planned, as shown in Figure 6-35.

2. After selecting the BTSs that are not to be PN planned, the user can continue to

conduct the PN planning according to the normal planning method mentioned

above.

23


Figure 6-35 The Selection of BTSs to be PN Planned

六.5.7 PN Planning of Capacity-expanded BTS

As for the PN planning of the capacity-expanded BTS, firstly cancel checking the box

before original BTSs which means the original PN planning will be maintained. Then

check the box before capacity-expanded BTSs and conduct the PN planning with the

normal planning method.

24

Date post:	28-Oct-2014
Category:	Documents
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CDMA Network Planning and Optimization Training Guide for Po

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