Radio Fine Tuning.pdf

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B11 Introduction to Radio Fine Tuning- Page 1All Rights Reserved Alcatel-Lucent 2008

All Rights Reserved Alcatel-Lucent 2008

Base Station SubsystemB10 Introduction to Radio Fine

Tuning

STUDENT GUIDE

3FL10493AEAAZZZZA Issue 3

All rights reserved Alcatel-Lucent 2008Passing on and copying of this document, use and communication of its

contents not permitted without written authorization from Alcatel-Lucent


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All RightsReserved Alcatel-Lucent 2008

B11 Introduction to Radio Fine TuningBase Station Subsystem

2

Empty page

Switch to notes view!

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3

Terms of Use and Legal Notices

Switch to notes view!1. Safety WarningBoth lethal and dangerous voltages may be present within the products used herein. The user is strongly advised not to

wear conductive jewelry while working on the products. Always observe all safety precautions and do not work on the

equipment alone.

The equipment used during this course may be electrostatic sensitive. Please observe correct anti-static precautions.

2. Trade Marks

Alcatel-Lucent and MainStreet are trademarks of Alcatel-Lucent.

All other trademarks, service marks and logos (Marks) are the property of their respective holders, including Alcatel-

Lucent. Users are not permitted to use these Marks without the prior consent of Alcatel-Lucent or such third party owning

the Mark. The absence of a Mark identifier is not a representation that a particular product or service name is not a Mark.

Alcatel-Lucent assumes no responsibility for the accuracy of the information presented herein, which may be subject tochange without notice.

3. Copyright

This document contains information that is proprietary to Alcatel-Lucent and may be used for training purposes only. Noother use or transmission of all or any part of this document is permitted without Alcatel-Lucents written permission, andmust include all copyright and other proprietary notices. No other use or transmission of all or any part of its contents may

be used, copied, disclosed or conveyed to any party in any manner whatsoever without prior written permission from

Alcatel-Lucent.

Use or transmission of all or any part of this document in violation of any applicable legislation is hereby expressly

prohibited.

User obtains no rights in the information or in any product, process, technology or trademark which it includes ordescribes, and is expressly prohibited from modifying the information or creating derivative works without the express

written consent of Alcatel-Lucent.

All rights reserved Alcatel-Lucent 2008

4. Disclaimer

In no event will Alcatel-Lucent be liable for any direct, indirect, special, incidental or consequential damages, including

lost profits, lost business or lost data, resulting from the use of or reliance upon the information, whether or not Alcatel-

Lucent has been advised of the possibility of such damages.

Mention of non-Alcatel-Lucent products or services is for information purposes only and constitutes neither an

endorsement, nor a recommendation.

This course is intended to train the student about the overall look, feel, and use of Alcatel-Lucent products. Theinformation contained herein is representational only. In the interest of file size, simplicity, and compatibility and, in some

cases, due to contractual limitations, certain compromises have been made and therefore some features are not entirely

accurate.

Please refer to technical practices supplied by Alcatel-Lucent for current information concerning Alcatel-Lucent equipment

and its operation, or contact your nearest Alcatel-Lucent representative for more information.

The Alcatel-Lucent products described or used herein are presented for demonstration and training purposes only. Alcatel-

Lucent disclaims any warranties in connection with the products as used and described in the courses or the relateddocumentation, whether express, implied, or statutory. Alcatel-Lucent specifically disclaims all implied warranties,

including warranties of merchantability, non-infringement and fitness for a particular purpose, or arising from a course of

dealing, usage or trade practice.

Alcatel-Lucent is not responsible for any failures caused by: server errors, misdirected or redirected transmissions, failed

internet connections, interruptions, any computer virus or any other technical defect, whether human or technical in

nature

5. Governing Law

The products, documentation and information contained herein, as well as these Terms of Use and Legal Notices are

governed by the laws of France, excluding its conflict of law rules. If any provision of these Terms of Use and Legal

Notices, or the application thereof to any person or circumstances, is held invalid for any reason, unenforceable including,

but not limited to, the warranty disclaimers and liability limitations, then such provision shall be deemed superseded by a

valid, enforceable provision that matches, as closely as possible, the original provision, and the other provisions of these

Terms of Use and Legal Notices shall remain in full force and effect.


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4

Blank Page




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5

Course Outline

About This CourseCourse outline

Technical support

Course objectives

1. Topic/Section is Positioned HereXxx

Xxx

Xxx

2. Topic/Section is Positioned Here






1. Radio Fine Tuning

1. Typical Radio Problems

2. Algorithms and Associated Parameters

3. Other Algorithms

4. Algorithms Dynamic Behaviors

5. Case Studies

6. Annexes


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6

Course Outline [cont.]




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7

Course Objectives


Welcome to Introduction to Radio Fine Tuning B10

Upon completion of this course, you should be able to:

Characterize the usual radio problems and decide on the appropriate maintenance team

List and describe BSS radio algorithms and related parameters

List radio parameters and verify conformity with Alcatel standards

Estimate the qualitative impact of an algorithm parameter change

Propose algorithm parameter setup to solve typical radio problems for conventionalnetworks

Hierarchical, dual-band, frequency hopping, concentric cell and GPRS networks are not covered.


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8

Course Objectives [cont.]




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9

About this Student Guide

Switch to notes view!Conventions used in this guide

Where you can get further information

If you want further information you can refer to the following:

Technical Practices for the specific product

Technical support page on the Alcatel website: http://www.alcatel-lucent.com

Note

Provides you with additional information about the topic being discussed.

Although this information is not required knowledge, you might find it useful

or interesting.

Technical Reference(1) 24.348.98 Points you to the exact section of Alcatel-Lucent Technical

Practices where you can find more information on the topic being discussed.

WarningAlerts you to instances where non-compliance could result in equipment

damage or personal injury.


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10

About this Student Guide [cont.]




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11

Self-assessment of Objectives

At the end of each section you will be asked to fill this questionnaire

Please, return this sheet to the trainer at the end of the training


Instructional objectivesYes (orglobally

yes)

No (orglobally

no)Comments

1 To be able to XXX

2

Contract number :

Course title :

Client (Company, Center) :

Language : Dates from : to :

Number of trainees : Location :

Surname, First name :

Did you meet the following objectives ?

Tick the corresponding box

Please, return this sheet to the trainer at the end of the training


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12

Self-assessment of Objectives [cont.]


Instructional objectivesYes (orGlobally

yes)

No (orglobally

no)Comments

Thank you for your answers to this questionnaire

Other comments


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Section 1 Module 1 Page 1


3JK11052AAAAWBZZA Issue 3.0

Do not delete this graphic elements in here:

11All Rights Reserved Alcatel-Lucent 2009Module 1

Typical radio problems3JK11052AAAAWBZZA Issue 3.0

Section 1B10 Introduction to Radio Fine

Tuning

Base Station SubsystemB10 Introduction to Radio Fine Tuning

3FL10493AEAAZZZZA Issue 3.0


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Base Station Subsystem B10 Introduction to Radio Fine TuningB10 Introduction to Radio Fine Tuning Typical radio problems

1 1 2

Blank Page


First editionLast name, first nameYYYY-MM-DD01

RemarksAuthorDateEdition

Document History


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1 1 3

Module Objectives

Upon completion of this module, you should be able to:

Characterize typical radio problems in order to trigger an intervention of theappropriate team


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1 1 4

Module Objectives [cont.]



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1 1 5

Table of Contents

Switch to notes view!Page

1 Theoretical Presentation 72 Coverage Problem 9

3 Interference Problem 184 Unbalanced Power Budget Problem 325 TCH Congestion Problem 386 Deducing the Right Team for Intervention 43


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1 1 6

Table of Contents [cont.]




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1 1 7

1 Theoretical Presentation


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1 1 8


Justification

Several sources of information can alert RFTM team:

QoS indicators

Customers complaints Drive tests

Other teams information (NSS statistics)

As many symptoms are common to several causes, it can be necessaryto:

Consolidate standard sources of information

Carry out specific examinations

Deduce the appropriate team for intervention


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1 1 9

2 Coverage Problem


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1 1 10

2 Coverage Problem

Definition and Symptoms

Definition: Bad coverage

A network or cell facing coverage problems presents a bad RxLev and RxQual

at the same time on some areas.

Symptoms:

Customers complain about dropped calls or/and no network

OMC QoS indicators

TCH failure rate

Call drop rate

Low proportion of better cell HO

High rate of DL quality HO

A interface indicators

High rate of Clear Request messages, cause radio interface failure

No information is available on non-covered parts of the network, as there are non-mobiles making calls over

there!

Nevertheless, cells in border of non-covered zones do have a particular behavior:

Cell A will mainly perform Better Cell handovers towards its neighbors, whereas cell B, bordering the non-

coverage area, will perform emergency handovers for MSs exiting the network.

For these MSs, mainly DL Quality HO will be triggered:

DL because MS antenna is less efficient than BTS one,

Quality rather than Level since Qual has a greater priority in Alcatel-Lucent HO causes.

AB


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1 1 11

2 Coverage Problem

Examination

Depending on the information sources you have:

Radio Measurement Statistics (RMS)

(RxLevel , RxQuality) matrix Radio Link Counter S vector

Number of calls with DL/UL bad coverage (bad RxLev, bad RxQual)

Abis interface (for example with COMPASS)

bad quality > 5%

bad level RxLev < - 95 dBm and RxQual > 4

OMC-R or A interface

unexpected high traffic, induced by call repetition

Billing information

High recall rate detected

RMS:

Provides statistics from any area in the network which are available at any time.

Cost-effective.

Easier and cheaper to perform than Drive test or Abis Trace.

The operator can tune 54 parameters (based on RxLev, BFI, C/I, Radio Link Counter S, Path Balance, etc.)

to define up to 16 templates (depending on cell type rural, urban, etc. for example).

Trigger from the OMC-R.

NPO can save up to 15 days of RMS for the complete network.

Templates can be designed in NPO.

Default result reports are available in NPO.


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1 1 12

2 Coverage Problem

Typical Causes

If the actual coverage is not the one predicted by RNP tools:

check antenna system

increase or decrease antenna down-tilt check BS_TXPWR_MAX

to be increased if value different from RNP power budget

If the actual coverage is OK compared to the predicted ones:

indoor traffic, to be handled by specific means

if black spot close to cell border, ease outgoing HO


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1 1 13

2 Coverage Problem

Investigation with Abis Trace

Example of an Abis trace analysis

TRX index RxLev_UL RxLev_DL RxQual_UL Path_loss_UL Path_loss_DL delta_Path_loss Delta_quality AV_MS_PWR Nb_of_samplesRxQual_DL

TRX index Qual0 Qual1 Qual2 Qual4 Qual5 Qual6 Qual7 Bad_QualityQual3

TRX index Qual0 Qual1 Qual2 Qual4 Qual5 Qual6 Qual7 Bad_QualityQual3

1 -89.29 -84.67 0.42 123.82 123.67 -0.15 -0.01 34.53 30740.43

2 -89.77 -89.09 0.41 124.87 128.09 3.21 0.03 35.11 10 2530.38

3 -83.15 -79.15 0.69 116.05 121.22 5.16 -0.16 32.9 53391.12

DISTRIBUTION OF UPLINK QUALITY

1 86.50% 3.19% 2.50% 1.92% 2.08% 0.98% 0.26% 3.32%2.57%

2 88.11% 1.82% 1.91% 2.14% 2.17% 1.15% 0.19% 3.51%2.51%

3 77.70% 4.30% 4.30% 3.56% 3.56% 1.70% 0.17%4.36%

1 88.29% 1.82% 2.05% 1.30% 1.46% 1.76% 0.94% 4.16%2.37%

2 87.50% 2.98% 2.60% 2.11% 1.14% 0.74% 0.50% 2.38%2.43%

3 71.30% 3.82% 4.02% 4.16% 4.30% 4.23% 3.16%4.89%

DISTRIBUTION OF DOWNLINK QUALITY

5.43%

11.73%

It could have been coverage problems if this trace was made for 3 mono-TRX cells. In this case, the 3 lines

are uncorrelated. Anyway, delta path loss of frequency 111 is greater than 5dB, showing a problem on thisTRX.

If this is a 3-TRX cell, it cannot be a coverage problem as the three TRXs are not impacted. It will be either

interference or malfunction of one TRE.

If the trace is done on 3 mono-TRX cells, in that case, it could be a coverage problem. Be careful when

interpreting this result table: even if average levels in the UL and the DL are high and a lot of Quality

problems are seen, nobody can say that samples with bad quality have a good level! The level seen is just

an average

One should have a look at the next slide

Note: Delta Path Loss = Path Balance (as computed in NPO)

= (BTS TXPWR RXLEV DL) (MS TXPWR RXLEV UL)

= (39 89.09) (35.11 89.77) = 3.21


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1 1 14

2 Coverage Problem

Investigation with Abis Trace [cont.]


Thresholds

Bad Coverage

RxLev -95

RxQual > 4

Interference

RxLev > -95

RxQual > 4

3-88.006

3-95.333

1-71.003 1-80.006

1-80.003 -80.003

5

7

111

1212

Number_UL: 10 253

Number_DL: 10 253

Int_UL: 2BC_UL: 358

Int_DL: 0%

0.02%

3.49%

67-

104.64

20

48-

107.50

51

Number_UL: 5339

Number_DL: 5339

Int_UL: 0BC_UL: 290

Int_DL: 0%BC_DL: 626

0.00%

5.43%

SamplesBSIC

63-101.542

SamplesBSICNeigh_Cell_Nb

SamplesBSICNeigh_Cell_Nb

= -102.17 dBm3.74%BC_DL: 115

57-100.5320

45-98.71210

34-98.0365

33-98.6137

= -106.56 dBm

BC_DL: 244 2.38% = -106.17 dBm

Frequency: 92

Frequency: 111

11.73%

Neigh_Cell_Nb10

All samples are Bad Coverage samples (BC). None is interference, showing that this cell is not facing any

interference problem.

By the way, if the cell is:

mono-TRX, this is a coverage problem.

3 TRXs, this is a malfunction of the TRE (shown also by the high value of delta_path_loss).


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1 1 15

2 Coverage Problem

Investigation with RMS

Suspecting a cell coverage problem

Distribution of samples per RxQual value and RxLev band

Distribution of samples per RxLev band

0

1

2

4

5

7

[-110,-104[

[-104,-98[

[-98,-92[

[-92,-86[

[-86,-80[

[-80,-74[

[-74,-68[

[-68,-62[

[-62,-56[

[-56,-47[

RxQuality (Nb)

RxLevel(dB)

[0, 14 793]

]14 793, 23 446]

]23 446, 29 586]

]29 586, 34 348]

]34 348, 38 239]

]38 239, 41 529]

]41 529, 44 378]

]44 378, 46 892]

Out of RangeX

Interval of numberof samples

Downlink Samples Matrix in log scale

3

6

Not acceptable coverage limit:too low level

too bad quality

A coverage problem is observed when a significant amount of the traffic of a cell is suffering from both low

level and bad quality (RxQual).

To confirm, distribution of samples per RXLEV band should be also considered to know the proportion of

calls which are experiencing a low signal level.

If a lot of samples of low level and bad quality are observed for only a sub-part of the TRXs (can be one

only) then a BTS hardware problem or a problem on the antenna should be suspected.

If all the TRXs are experiencing a lot of samples of low level and bad quality then a coverage problem must

be suspected.

These RMS indicators are provided on the NPO tool per TRX, per Cell:

Matrix of Number of Measurement Results per DL RxQual value and per DL RxLev band

RMQLDSAM = RMS_DL_RxQuality_RxLevel_sample

Vector of Percentage of Samples per DL RxLev bandRMQLDLVDV = RMS_DL_RxLevel_distrib

Vector of Percentage of Samples per DL RxQual band

RMQLDQUDV = RMS_DL_RxQuality_distrib


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1 1 16

2 Coverage Problem

Investigation with RMS [cont.]

Suspecting a cell coverage problem

Average TA values per RxQual value and RxLev band

16.00%

14.00%

12.00%

10.00%

8.00%

6.00%

4.00%

2.00%

0.00%

01/12/2001

01/01/2002

02/01/2002

03/01/2002

04/01/2002

05/01/2002

06/01/2002

07/01/2002

08/01/2002

09/01/2002

10/01/2002

11/01/2002

12/01/2002

13/01/2002

14/01/2002

10

9

8

7

6

5

4

3

2

1

0

%N > TA thres TA max

Maximum Timing Advance and TA > threshold

N > TA thresTA max

TA thresholdAcceptablecoverage limit:

sufficient level andgood quality

Not acceptablecoverage limit:

too low level andtoo bad quality

% of TA valueover TA threshold

has also to beconsidered

0

1

2

4

5

7

[-110,-104[

[-104,-98[

[-98,-92[

[-92,-86[

[-86,-80[

[-80,-74[

[-74,-68[

[-68,-62[

[-62,-56[

[-56,-47[

RxQuality (Nb)

RxLevel(dB)

[0, 2]

]2, 4]

]4, 6]

]6, 8]

Out of Range

Interval of averageTiming Advance

Uplink average TA Distribution

3

6

X

Down

In order to know if the coverage problem is due to a big amount of traffic at the cell border or rather to

indoor calls, the average TA value per RXQUAL value and RXLEV band as well as the Percentage of TAvalues over TA threshold should be observed:

Matrix of Average TA per UL RxQual value and per UL RxLev band

RMQLUTAM = RMS_UL_RxQuality_RxLevel_TimingAdvance

Rate of Measurements Results whose TA is greater than the TA threshold

RMTAGTR = RMS_TimingAdvance_greater_threshold_rate

Maximum TA value of all values reported in Measurement Results

RMTAMXN = RMS_TimingAdvance_max


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1 1 17

2 Coverage Problem

Investigation with RMS [cont.]

Suspecting a local cell coverage problem

RxQual and RxLev per TA bands

5

4

3

2

0

1

2.5

[0,5[ [6,11[ [55,63[[49,54[[43,48[[37,42[[31,36[[25,30[[19,24[

[12,18[

-47

- 60

- 70

- 80

- 110

- 90

- 59

[0,5[ [6,11[ [55,63[[49,54[[43,48[[37,42[[31,36[[25,30[[19,24[

[12,18[

Bad quality

and bad Level

for a specific TA band

Coverage problem

In order to know if the coverage problem is due to a big amount of traffic at the cell border or rather to

indoor calls, the average TA value per RXQUAL value and RXLEV band as well as the Percentage of TAvalues over TA threshold should be observed:

Matrix of Average TA per UL RxQual value and per UL RxLev band

RMQLUTAM = RMS_UL_RxQuality_RxLevel_TimingAdvance

Rate of Measurements Results whose TA is greater than the TA threshold

RMTAGTR = RMS_TimingAdvance_greater_threshold_rate

Maximum TA value of all values reported in Measurement Results

RMTAMXN = RMS_TimingAdvance_max


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1 1 18

3 Interference Problem


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1 1 19



Definition: Interference

A network facing interference problems presents good RxLev and bad RxQual

at the same time on some areas.

Symptoms

Customers complain about bad speech quality (noisy calls) and/or call drops

OMC QoS indicators:

SDCCH/TCH Drop

Low proportion of better cell HO

High rate of DL/UL quality HO and interference HO

Low HO success rate



DL/UL depends on the way on which the interference is present.

Mainly, interferences are in the DL, due to bad frequency planning introducing interferences in the

network. And this problem will not change till the frequency plan is not returned

Sometimes, interference can be in the UL in very dense area (for example, microcell area), since MSs are

very close.

Finally, sometimes interferences are not coming from BS or MS but from another radio equipment, either in

the UL or the DL.


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1 1 20


Examination with RMS

Radio Measurement Statistics (RMS)

RxQual/RxLev matrix

CFE/RxLev matrix C/I vectors for neighbors

C/I vectors for MAFA frequencies

MAFA is a new standardized GSM feature for mobiles

MAFA mobiles can provide C/I measurements from non-neighbor cells

Number of calls with DL/UL interference (good RxLev, bad RxQual)

Number of noisy calls (bad RxQual) with bad voice quality (bad FER)

A high rate use of the most robust AMR codecs also denounces interferences

problems. But be careful, this can also be due to a pessimistic choice of the

thresholds used for codec change.

The feature Radio Measurement Statistics (RMS) is designed to make far easier the work for planning and

optimization of the network by providing the operator with useful statistics on reported radiomeasurements.

In fact these statistics give directly the real cell characteristics by taking into account the MS distribution.

Thanks to this feature, the operator is able to:

detect interfered frequencies.

assess the quality of the cell coverage.

detect and quantify cell unexpected propagation.

assess the traffic distribution in the cell from statistics on reported neighboring cells.

evaluate the voice quality in the cell.

etc.

In regards to the RTCH Measurements Observation (measurement type 11), the Radio Measurement

Statistics feature (RMS) brings the following advantages:

smaller report files.

the report files always have the same maximum length no matter what the measurement duration is.

every measurement is taken into account (no sampling).

no more need for measurement post-processing tools for statistics. Directly available with NPO.


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1 1 21


Examination with RMS [cont.]

Suspecting a cell interference problem

Number of samples per RxQual value and RxLev band

Quality problems are obvious at anylevel of RMS data

Interference highlighted

Network fine tuning needed

0

1

2

4

5

7

[-110,-104[

[-104,-98[

[-98,-92[

[-92,-86[

[-86,-80[

[-80,-74[

[-74,-68[

[-68,-62[

[-62,-56[

[-56,-47[

RxQuality (Nb)

RxLevel(dB)

[0, 14 793]

]14 793, 23 446]

]23 446, 29 586]

]29 586, 34 348]

]34 348, 38 239]

]38 239, 41 529]

]41 529, 44 378]

]44 378, 46 892]

Out of RangeX


Downlink Samples Matrix in log scale

3

6

Average RxQual value per RXLev bandhas also to be considered

0

1

2

3

4

5

6

[-110,-104[

[-104,-98[

[-98,-92[

[-92,-86[

[-86,-80[

[-80,-74[

[-74,-68[

[-68,-62[

[-62,-56[

[-56,-47[

RxQuality(Nb)

RxLevel(dB)

Downlink average RxQuality per RxLevel

RxQualityAverage

5

Average DL RxQuality = 2.81


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1 1 22



Suspecting a Voice Quality problem

Number of samples per BFI band and RxLev band

0

1

2

3

4

5

6

[-110,

-104[

[-104,

-98[

[-98,

-92[

[-92,

-86[

[-86,

-80[

[-80,

-74[

[-74,

-68[

[-68,

-62[

[-62,

-56[

[-56,

-47[

Average CFE

RxLevel (dB)

Uplink average Consecutive Frame Erasure per RxLevel

78

Average RxQual

0

1

2

3

4

5

6CFE

Average

RxQualityAverage

Consecutive Frame Erasure (BFI) is a

measurement based on loss of consecutivespeech frames over one SACCH mw.

It is directly linked to Voice Quality.

RxQual to be compared with CFE since BadRxQual does not always mean bad VQ.

[0, 1[

[1, 2[

[2, 4[

[6, 8[

[8, 10[

[14, 18[

[-110,-104[

[-104,-98[

[-98,-92[

[-92,-86[

[-86,-80[

[-80,-74[

[-74,-68[

[-68,-62[

[-62,-56[

[-56,-47[

CFE (Nb)

RxLevel(dB)

[0, 14 793]

]14 793, 23 446]

]23 446, 29 586]

]29 586, 34 348]

]34 348, 38 239]

]38 239, 41 529]

]41 529, 44 378]

]44 378, 46 892]

Out of RangeX


Consecutive Frame Erasure Matrix in log scale

[4, 6[

[10, 14[

[14, 18[

[14, 18[[22, 25[

[18, 22[

[14, 18[


Matrix of Number of Measurements Results per CFE band (or BFI band) and per UL RxLev band

RMFEM = RMS_UL_ConsecutiveFrameErasure_RxLevel_sample

Vector of Average number of Consecutive Frame Erasure per UL RxLev band

RMFEBFAV = RMS_UL_ConsecutiveFrameErasure_avg_per_RxLevel

Vector of Average UL RxQual per RxLev band

RMQLUQUAV = RMS_UL_RxQuality_avg_per_RxLevel


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1 1 23



Suspecting a local interference problem

RxQual and RxLev per TA bands

5

4

3

2

0

1

2.5

[0,5[ [6,11[ [55,63[[49,54[[43,48[[37,42[[31,36[[25,30[[19,24[

[12,18[

Bad quality

and good Level

for a specific TA band

interference problem

-47

- 60

- 70

- 80

- 110

- 90

- 59

[0,5[ [6,11[ [55,63[[49,54[[43,48[[37,42[[31,36[[25,30[[19,24[

[12,18[


Matrix of Number of Measurements Results per CFE band (or BFI band) and per UL RxLev band

RMFEM = RMS_UL_ConsecutiveFrameErasure_RxLevel_sample

Vector of Average number of Consecutive Frame Erasure per UL RxLev band

RMFEBFAV = RMS_UL_ConsecutiveFrameErasure_avg_per_RxLevel

Vector of Average UL RxQual per RxLev band

RMQLUQUAV = RMS_UL_RxQuality_avg_per_RxLevel


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1 1 24


Typical Causes

GSM interference

co-channel

adjacent

Non-GSM interference

other Mobile Networks

other RF sources


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1 1 25


GSM Interference: Co-Channel

GSM Interference

Co-Channel interference

If C/I < 12dB (9dB according to GSM), then the call suffers bad quality

Level

Frequency

F(BTS1)

-12 dB

F(BTS2)

F(BTS1) = F(BTS2)

- 12dB


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1 1 26


GSM Interference: Co-Channel [cont.]

Co-channel interference

Symptom

Usually downlink interference High rate of quality HO, call drop and call failure

Examination

Neighbor cells in Abis trace (only for BCCH)

Non-neighbor cells in RMS (MAFA frequencies)

Frequency planning C/I < 12 dB

Correction

Downtilt increase of interferer, or even change of antenna orientation

Reduction of BS power, Change of frequency

Concentric cell implementation (1 extra TRX needed if traffic cannot be supportedby Outer+Inner configuration)


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1 1 27


GSM Interference: Adjacent Channels

Adjacent channel interference

If C/I < -6dB (-9dB according to GSM), then the call suffers bad quality

Level

Frequency

F(BTS1)

6 dB

F(BTS2)

F(BTS1) = F(BTS2)+1

- 6dB


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1 1 28


GSM Interference: Adjacent Channels [cont.]

Adjacent channel interference:

Symptom

Usually downlink interference High rate of quality HO, call drop (due to HO but mainly due to radio) and TCH

assignment failure

Examination

Neighbor cells in Abis trace (only for BCCH)

Non-neighbor cells in RMS (MAFA frequencies)

Frequency planning C/(I adjacent) < -6dB

Correction

Downtilt increase of interferer, or even change of antenna orientation

Reduction of BS power if necessary, Change of frequency (best solution)

Concentric cell implementation (1 extra TRX needed if traffic cannot be supportedby Outer+Inner configuration)


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1 1 29


GSM Interference: cellular

GSM interference: cellular

BTS1: ARFCN 5

BTS2: ARFCN 6

MS1 indoor

RxLev_UL: - 90 dBm

MS2 outdoor, connected to BTS2

1: no level on BTS1(BTS 1 under-roof)

2: - 80 dBm on BTS1:

interferer UL/DL 3: no level on BTS1

cell algo prevents BTS2->BTS1 HO

MS 1(indoor)

MS 2(outdoor)

1

2

3

BTS 1(Micro)

BTS 2

When interferences are created by frequency planning, its not so hard to detect them. But frequency

planning tools mainly consider DL C/I and coverage.

Some problems are more difficult to predict. For example, lets consider a microcell layer:

A and B are 2 microcells with the coverage described before in dense urban environment.

Even if both cells A & B are using adjacent frequencies (5 and 6), the overlapping area is far from cell A

antenna. Thus, in this area C/I is lower than 6 dB.

A red MS is connected to cell A. When the MS starts its call, it transmits full power and a PC algorithm

quickly reduces MS power as the received level is very good (microcell coverage). When MS A enters the

building, it faces a loss of signal of 20 dB. Then, the MS power increases to MS_TXPWR_MAX.

A second mobile B is connected to cell B and moves down in the coverage area of cell B. The MS power

of B decreases quickly down to MS_TXPWR_MIN as the MS is close to the antenna. But when MS B arrives

outside the building where A is sitting, A and B are close and transmitting on adjacent frequencies Then Bhas to increase its power to avoid dropping its call. By the way, global level of freq B is increased in all cell

B creating interference in the UL.

A

B


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1 1 30


GSM Interference: Forced Directed Retry

GSM Interference: Forced Directed Retry

The MS should connect to cell2, but no TCH

available The MS connects to cell 1 with forced

directed retry

The MS is emitting at high level (far fromBTS1)

UL interference for BTS 3

BTS 1 is emitting at high level

DL interference at BTS 3

Ce

ll2:45Cell3:23

Ce

ll

1:24

MS

BTS 2

BTS 1

BTS 3

Another more difficult case of interference: FDR

When examining the preceding situation of planning tool: no problem of C/I. No risk of interference.

The FDR algorithm allows an MS connected on an SDDCH on a cell without any free TCH to make an

SDCCH-TCH handover (cause 20) so that it takes a TCH on its neighbor. As seen from the user, this is not a

handover (call establishment phase, no impact on speech quality), and this algorithm is very efficient to

avoid cell congestion cases.

This algorithm is mainly based on neighbor level compared to parameter L_RXLEV_NCELL_DR (n). If the

level greater than this threshold, the TCH is to be seized on neighbor.

FDR is mandatory for dual layer or dual band networks (and very easy to configure in this case), since we

have capture handovers. Capture handovers send traffic to lower or preferred band cells. In case these

cells are congested, calls may not be established, even if upper or non-preferred band cells are free (due

to MS idle mode selection, advantaging microcell for example). With the FDR algorithm, the MS takes an

SDCCH in the preferred cell, and FDR is used to take a TCH on the non-preferred cell in case of congestion.This situation highlights a good network behavior, since the MS is at the same time in the coverage area of

both cells (preferred and not preferred).

The situation described on the slide corresponds to the usage of FDR in a single layer network. This is inthat case a heavy-to-tune algorithm presenting of lot of interference and bad quality call risks, since the

mobile will be connected to a cell when being not in its service area.

umbrella

microcell

FDRcapture


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1 1 31


Non-GSM Interference

Other mobile networks: TACS/AMPS/NMT900

Inter-modulation with GSM BS/MS receiver

Spurious RACH for AMPS (AMPS Tx bands close to GSM uplink band) Examination

TASC: coverage hole with 600 m from TASC BTS

AMPS => 50% reduction of range if AMPS/GSM BTS collocated

Other RF interferers (Radar, shop anti-theft mechanisms, medicaldevice, etc.)

Other RF interferers:

medical devices: GSM equipment disturb them more than the opposite!

anti-theft mechanisms.

Example:

The Microcell is showing a very high call drop rate. On one frequency, very small call duration.

No problem seen in the frequency plannig. No potential interferer.

Abis trace:

The Spectrum analyzer connected on the antenna feeder highlights a peak on GSM freq 6 in the UL

Anti-theft mechanism turned off: no more problem

shop

Microcellantenna

Qual

Level

Qual

Level

DL UL

interference


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1 1 32

4 Unbalanced Power Budget Problem


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1 1 33



Definition: Unbalanced power budget

A cell facing unbalanced power budget problems presents a too high path-

loss difference between UL and DL (often DL>UL) Rule: try to have delta as small as possible to avoid access network possible

only in 1 direction (usually BTS->MS: OK and MS->BTS: NOK)

Symptoms:

OMC QoS indicators

High rate of Uplink quality Handover causes

Low incoming HO success rate (no HO Access triggered on the uplink)

Degradation of TCH failures and OC call drop indicators



O&M Alarms Voltage Standing Wave Ratio BTS Alarm (VSWR)

TMA Alarm (in case of G2 BTS or Evolium BTS with high power TRE)

UL Quality HO is triggered:

UL since the problem is in the UL.

Quality as Quality has greater priority than level.


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1 1 34


Examination

RMS:

Path Balance vector per TRX

Number of calls with abnormal bad FER (good RxQual & bad FER)

Abis monitoring:

|delta path-loss| > 5dB

Check if problem is occurring for 1 TRX or all

Problem on 1 TRX: FU/CU or TRE problem or ANY problem or cables connected to this equipment.

All TRXs: problem on antenna, feeder, jumper or common equipment (e.g., ANX, ANC).


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1 1 35


Abis Trace


106 -94.52 -87.19 0.43 127.55 130.19 -2.64 0.18 33.03 20660.25

Frequency Qual0 Qual1 Qual2 Qual4 Qual5 Qual6 Qual7 Bad_QualityQual3

Frequency Qual0 Qual1 Qual2 Qual4 Qual5 Qual6 Qual7 Bad_QualityQual3

89 -84.29 -75.17 0.65 115.32 118.17 -2.85 0.21 31.03 20010.44

118 -90.75 -83.36 0.46 123.22 126.36 -3.14 0.04 32.46 31930.41

124 -88.89 -85.30 0.29 120.48 128.30 -0.37 31.59 29310.67

DISTRIBUTION OF UPLINK QUALITY

106 84.75% 4.07% 3.68% 1.36% 1.50% 0.92% 0.53% 2.95%3.19%

89 81.41% 1.70% 2.95% 6.35% 2.55% 1.30% 0.10% 3.95%3.65%

118 83.62% 4.23% 4.23% 1.57% 1.79% 0.97% 0.25%3.35%

106 90.27% 3.44% 2.08% 0.92% 1.36% 0.34% 0.05% 1.74%1.55%

89 80.16% 6.45% 7.00% 1.50% 0.50% 0.45% 0.10% 1.05%3.85%

118 86.78% 2.72% 3.95% 1.41% 1.13% 1.19% 1.00%1.82%

DISTRIBUTION OF DOWNLINK QUALITY

3.01%

3.32%

Frequency RxLev_UL RxLev_DL RxQual_UL Path_loss_UL Path_loss_DL delta_Path_loss Delta_quality AV_MS_PWR Nb_of_samplesRxQual_DL

-7.82

124 90.79% 1.06% 2.18% 1.77% 1.30% 0.48% 0.07%2.35% 1.84%

124 77.14% 4.37% 5.87% 3.48% 1.36% 0.82% 1.02%5.94% 3.21%


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1 1 36


RMS Data

Suspecting a TRX hardware problem

Average Path Balance

A fair average Path Balance at Cell level can hide a bad value for one TRX

0

500

1000

1500

2000

2500

3000

[-110,-20[

[-20,-10[

[-10,-6[

[-6,-3[

[-3,0[

[0,3[

[3,6[

[6,10[

[10,20[

[20,110[

Nb Samples

PathBalance(dB)

NbSamples

PathBalance Distribution

Average Cell Path Balance = - 0.9 dB


Vector of the Number of Measurement Results per Path Balance band

RMPBV = RMS_PathBalance_sample

Average Path Balance value

RMPBAN = RMS_PathBalance_avg


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1 1 37


Typical Causes

Antennas or common RF components, TMA (pb common to all TRXs ofthe BTS)

TRX RF cables/LNA ... if problem located on only 1 FU

Every BTS has its proper architecture and the diagnosis must be adapted.


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1 1 38

5 TCH Congestion Problem


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1 1 39



Definition: TCH Congestion

TCH Congestion rate (TCH Assignment Phase) is too high (more than 2%)

Rule: try to meet the offered traffic (asked by users) by providing the rightnumber of resources (TRX extension)

Symptoms:

Customers complain about Network busy

OMC QoS indicators

High TCH Congestion rate

Low incoming Intra/Inter BSC HO success rate (no TCH available)

High Directed Retry rate if activated

A interface indicator: BSS Congestion failure in OC

High rate of Assignment Failure messages, No radio resource available


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1 1 40


Examination and Typical Causes

Examination: TCH Congestion

On a per cell basis examination, check the evolution of the TCH Congestion

rate. Typical causes:

Special events:

Foreseeable: football match, important meeting Activate some TRXs already installed (and use Synthesized FH)

Add special moving BTSs

Not foreseeable: car crash on the highway

Cells on wheel operational by several operators around the world for special events coverage & capacity:

IRMA (SFR) connected to Caens BSC.

Orange coverage / Football WC 1998 for Paris Stade de France :

Specific cells covering Paris Stadium. During games, only small capacity (using joker frequencies).

During breaks, some TRX off-cells around are turned off, and frequencies are reused for stadium cells.


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1 1 41


Typical Causes

Daily periodic problems

At peak hour, the cell is not correctly dimensioned.

Hardware solution (refer to Annex)

Estimate the offered traffic:

At OMC-R level: Traffic in Erlang/(1- TCH Congestion rate)

Use the B-Erlang law to estimate the number of TCHs required for a 2%

blocking rate, thus the target configuration

Add TRXs to reach the new target configuration and find joker frequencies

and / or implement concentric cells

Warning: offered traffic is not the capacity delivered by the system but the traffic asked by the users.


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1 1 42


Typical Causes [cont.]

Daily periodic problems

At peak hour, the cell is not correctly dimensioned.

Software solution

Use specific densification features

Half Rate

Forced Directed Retry

Traffic handover

Fast Traffic handover

Candidate Cell Evaluation (FREEFACTOR / LOADFACTOR)

Half rate may not only mean SW solution. Need of G2 BSC/TC, Evolium TRE or G2 DRFU.


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1 1 43

6 Deducing the Right Team forIntervention


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1 1 44

6 Deducing the Right Team for Intervention

Process

Problem characterization

Make assumption causes

Check the tuning of default radio parameters

Consult the config. db Choose an (other) classical algo

Identify the tunable parameters

Impact estimation

Standard setting ?

No

Yes

Yes

No

No

Yes

Call expert

- Microcell, multiband- Concentric

=N

No

Yes

No

Yes

No

Yes

Parameters modificationDatabase updating

Impact simulation of aparameter modification

No

- Hopping- Marketing

Yes

QOS alarm on the network,on a BSC or some cells

- Indicators (% call drop)- Field measurements/planning- Subscriber complains

QOS team

DHCPEND

Drive test team

DHCPEND

Dimensionning team

OK

Correctionaction

Maintenance team

Planning team

NOK

Cell corrected ?Neighbor cell ?

RFT team - Interferences- Coverage (indoor)- Power budget- Congestion (TCH, SDCCH)- BSS problemInvestig problem ?

Planning/BSS causes

Standard parameters ?

Onpurpose

Systemproblem ?

SimulationOK ?

Recurrent problem ?

N times

Check ?With QOS ?


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1 1 45


Coverage Problem

In case of coverage problem:

If the field reality does not match the RNP prediction

Maintenance team to change physical configuration (tilt, azimuth, antenna height,etc.) and drive test team to check it

If the field reality matches the RNP prediction

Deployment team to add sites (tri-sector, micro cellular, indoor cells)


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1 1 46


Other Problems

In case of interference problem:

Planning team to identify the interference source and correct it (joker

frequency, new frequency planning, etc.)

In case of unbalanced power budget problem:

Maintenance team to check the impacted BTS (antennas, TMA, RF cables,LNA, diversity system, etc.)

In case of TCH congestion problem:

Traffic team (theoretically always in relation with the marketing team) tomanage the need of TRX extension, densification policy, etc.


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1 1 47

Exercise

Match the symptoms listed below with the corresponding problem.

High rate of UL QUAL HOcauses

Good RxLev and Bad RxQual

VSWR alarm (OMC-R)(Voltage Standing Wave Ratio)

Bad RxLev and Bad RxQual

OMC QOS indicators:% TCH ASS failure high% call drop high

% QUAL HO% call drop% call failure

Unbalanced

Power BudgetBad coverage Interferences

TCH

Congestion

High Path-loss differencebetween UL and DL

Low incoming HO successrate

Time allowed:

10 minutes


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1 1 48

Self-assessment on the Objectives

Please be reminded to fill in the formSelf-Assessment on the Objectives

for this module The form can be found in the first part

of this course documentation


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1 1 49

End of ModuleTypical radio problems


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Do not delete this graphic elements in here:

12All Rights Reserved Alcatel-Lucent 2009Module 2

Algorithms and Associated Parameters3JK11053AAAAWBZZA Issue 3.0

Section 1B10 Introduction to Radio Fine

Tuning

Base Station SubsystemB10 Introduction to Radio Fine Tuning

3FL10493AEAAZZZZA Issue 3.0


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Base Station Subsystem B10 Introduction to Radio Fine TuningB10 Introduction to Radio Fine Tuning Algorithms and Associated Parameters

1 2 2

Blank Page


First editionLast name, first nameYYYY-MM-DD01

RemarksAuthorDateEdition

Document History


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1 2 3

Module Objectives

Upon completion of this module, you should be able to:

Describe the Power control and Handover algorithms List the associated parameters


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1 2 4

Module Objectives [cont.]



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1 2 5

Table of Contents


1 Theoretical Presentation 72 Idle Mode Selection and Reselection 9

3 Radio Measurement Principles 174 Radio Measurement Data Processing 245 Radio Link Supervision and Power Control 326 Handover Detection 577 Handover Candidate Cell Evaluation 1418 Exercise 153


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1 2 6

Table of Contents [cont.]



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1 2 7



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1 2 8


Justification

When the detected problem does not concern another team (Networkplanning and frequency planning, Dimensioning, Radio engineering,Maintenance) or when the other teams cannot give any solution (tootight frequency planning, no additional TRX available, no financialbudget for new sites, etc.), the Radio Fine Tuning team has to find acompromise between:

High traffic density (Erl/km/Hz)

High quality of service (Call drop, CSSR, Speech quality, indoor, etc.)

Its role: take charge of radio resources management process

This process can be fully described by MS Selection/Reselection, PowerControl and Handover algorithms.

In-depth knowledge of these algorithms is required for tuning


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1 2 9

2 Idle Mode Selection and Reselection


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1 2 10


Selection and Reselection Principles

At startup (IMSI Attach), the MS selects a cell with:

best C1

once camped on one cell (in idle mode)

the MS can decide to reselect on another one if:

C1 criterion is too low

the MS cannot decode downlink messages

the current cell is becoming forbidden (e.g. barred)

the MS cannot access the cell

there is a better cell, regarding C2 criterion

Idle Mode

Status null: the Mobile Station (MS) is off Status search BCCH: the MS searches a broadcast channel with the best signal level (cell selection and

reselection)

BCCH list: up to 36 BCCH frequencies plus BSIC can be saved on SIM per visited network.

Look if frequencies of the BCCH list can be used.

No entries in the BCCH list, or the location is completely different: scan frequency band.

Status BCCH: the MS is synchronized on a BCCH. The MS camps on a cell.

The BTS sends the neighbor cells list (BCCH allocation BA) on BCCH in System Information (SI) 2,

2bis and 2ter if BSS parameter EN_INTERBAND_NEIGH in dual band networks:

GSM900 serving cell

GSM900 neighbor cells put into SI 2 GSM1800 neighbor cells put into SI 2ter/2bis

GSM1800 serving cell

GSM900 neighbor cells put into SI 2ter

GSM1800 neighbor cells put into SI 2/2bis

The MS measures RXLEV from BCCH of the serving and neighbor cells.

Camping on a cell is performed using C1 criterion only (the chosen cell is the one with the best

C1)

The MS needs to have access to the network.

The MS needs to be accessible by the network.

Reselection is done using the mechanisms referenced above.

handover algorithms in idle mode


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1 2 11


C1 Criteria

C1 Ensures that, if a call was attempted, it would be done with a sufficient downlink and

uplink received level

Based on 2 parameters, broadcasted on BCCH

RXLEV_ACCESS_MIN [dBm] (default -100dBm)

MS_TXPWR_MAX_CCH [dBm] (default 43dBm for GSM900, 30dBm for DCS1800)

Evaluated every 5 sec (minimum)

C1 = (RxLev - RXLEV_ACCESS_MIN) - Max(0, MS_TXPWR_MAX_CCH - P)

If C1 < 0, then "No Network Available" displayed on the phone.

What happens ifMS_TXPWR_MAX_CCH is kept at default value in GSM900 cells?

When the MS is at the cell border and receives -91dBm,C1 = (-91 + 100) Max(0, 43 33) = 9 10 = -1

The MS cannot establish a call in this cell !! Set MS_TXPWR_MAX_CCH to 33dBm

RXLEV_ACCESS_MIN [dBm] = minimum level to access the cell

MS_TXPWR_MAX_CCH [dBm] = maximum level for MS emitting

With:

P: max power of the MS depending on its class (99.9% of MS = 33dBm in GSM900 and = 30dBm in DCS1800)

RxLev: current measurement of the DL_RxLev


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1 2 12


C2 Criteria Normal setting

C2

CELL_RESELECT_PARAM_IND= not present

THEN C2=C1

CELL_RESELECT_PARAM_IND= present

THEN C2 = C1 + CELL_RESELECT_OFFSET - TEMPORARY_OFFSET (T)

With:

TEMPORARY_OFFSET (T) = TEMPORARY_OFFSET if T < PENALTY_TIME

TEMPORARY_OFFSET (T) = 0 if T > PENALTY_TIME

T is the duration a neighbour cell has spent in the neighbour list.

It starts from 0 when the neighbour has just been detected.

Note:

CELL_RESELECT_OFFSET: from 0 to 126 dB, step 2dB PENALTY_TIME: from 0=20s to 30=620s, step: 20s; 31=infinite

TEMPORARY_OFFSET: from 1=10dB to 6=60dB; 7 = infinite

Cell Selection and Cell Reselection Considering CELL_BAR_QUALIFY

In case of phase 2 MS and CELL_RESELECT_PARAM_IND=1, it is possible to set priorities to cells

CELL_BAR_QUALIFY

Two values:

0 = normal priority (default value)

1 = lower priority

CELL_BAR_QUALIFY Interacts with CELL_BAR_ACCESS (barring cell)

A phase 2 MS selects the suitable cell with the highest C2 (C1>0) belonging to the list of normal priority.

If no cell with normal priority is available then the MS would select the lower priority cell with the

highest C2 (C1>0).


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1 2 13


C2 Criteria Special setting

C2

CELL_RESELECT_PARAM_IND= present PENALTY_TIME = infinity

THEN C2 = C1 - CELL_RESELECT_OFFSET

This handicap is always applied, whichever the value of T.

If a cell is parametered with PT=31, it will be penalized compared to ALL itsneighbors.

This parameter is not recommended because it requires special care andcould be misunderstood by your colleagues.

You can have the same result by giving a bonus to neighbour cells rather thangiving a handicap to this particular cell.

Note:




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1 2 14


C2 Criteria Different Location Areas

C2

The MS will reselect a neighbour cell (n) as soon as:

if cells belong to same LA

C2(n) > C2(s)

if cells from a different LA

C2(n) > C2(s) + Cell_Reselect_Hysteresis

Note:




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1 2 15


Exercise 1

On this network example

List the parameters involved in the selection / reselection process

Time allowed:5 minutes

Cell

Sectorizedcell

CI=6169

GSM900

Concentriccell

(8564,1964)

(8564,6169)

(8557,1823)

Cell

CI=6271GSM900

CI=6270, GSM900

CI=1823GSM900

CI=1964GSM900


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1 2 16


Exercise 2

Find the selected cell by the MS

Cell1

Cell2

CI=6169

GSM900

Cell3

(8564,1964)

(8564,6169)

(8557,1823)

Cell

CI=6271GSM900

CI=6270, GSM900

CI=1823GSM900

CI=1964GSM900

Measurements RxLev (cell 1) RxLev (cell 2) RxLev (cell 3)

1

2

3

4

5

-80

-84

-88

-88

-89

-96

-90

-90

-87

-85

-104

-100

-87

-82

-78

The same parameters setting is applied in all the cells:

Rxlev_Access_min = -103 dBm for all cells

Cell_Reselect_Offset = 0 dB

Temporary_Offset = 0 dB

Penalty_Time = 0 (20 s)

Cell_Reselect_Hysteresis = 6 dB


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1 2 17

3 Radio Measurement Principles


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1 2 18


Radio Measurement Mechanisms

MS connected (TCH or SDCCH)

The serving cell gives the MS the list of the neighbor cells to listen to

Every SACCH, the MS reports to the serving cell via a measurementreport message:

Received level of 6 best cells(which can change)

DL level and qualityof serving cell

Bestc

ellBe

stcell

Be

stce ll Bestcel

l

Cell

Cell

Bestcell

Cell

Bestcell

Serving

cellSYS_INFO_5

message (list)

MS reporting

The BTS sends a SYS_INFO_5 message that contains the list of neighbor cells for connected mode (TheSYS_INFO_2 message contains the list of neighbor cells for idle mode).

Sys info 2bis, 2ter, 5bis and 5ter are also used for multiband networks.

MS reporting depends on EN_INTERBAND_NEIGH and on MULTIBAND_REPORTING parameters.The MS may report:

6 strongest cells of any band (MULTIBAND_REPORTING=0), or

5 strongest cells of the serving band + 1 strongest cell of another band(MULTIBAND_REPORTING=1), or

4+2 (MULTIBAND_REPORTING=2), or

3+3 (MULTIBAND_REPORTING=3).

RXLEV Range: [-110dBm, -47dBm]

Binary range: [0, 63]; 0=-110dBm, 63=-47dBm

The higher the physical or binary value, the higher the receiving level

RXQUAL

Range: [0.14%, 18.10%]

Binary range: [0, 7]; 0=0.14%, 7=18.10%

The lower the physical or binary value, the lower the bit error rate, the better the quality

0-2=excellent; 3=good; 4=ok; 5=bad; 6=very bad; 7=not acceptable


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1 2 19


Radio Measurement Mechanisms [cont.]

For each MS connected to the BTS(TCH or SDCCH)

UL received level and quality ismeasured every SACCH

The Timing Advance (TA) iscomputed

The UL information is gatheredinto the measurement report

This is the message result sent bythe BTS to the BSC

BSC

MS

DLme

asurements

UL

+DLmeasure

ments

BTS

Measurementreport

Measurementresult

Candidate cellevaluation

MeasurementsActive channelpreprocessing

Candidate cellevaluationHO & PCdecision

Candidate cellevaluation

PC execution

HO execution

The BSC is computing algorithms usually using average value (slidingwindow) of these measurements

The BTS starts sending MEASUREMENT RESULT messages as soon as it receives the RL ESTABLISH INDICATION message from the MS.

The BTS stops sending MEASUREMENT RESULT messages upon receipt of one of the two following messages:

DEACTIVATE SACCH

RF CHANNEL RELEASE

Every SACCH multiframe, the BTS:

receives the MEASUREMENT REPORT message from the MS. For power control and handover algorithms, this message contains

downlink measurements and, in the layer 1 header, the power used by the MS.

does uplink measurements.

reports the uplink and downlink measurements to the BSC in the MEASUREMENT RESULT message.

Input flows

Uplink radio signal: radio signal received on the Air interface.

BS_TXPWR_CONF: BS transmit power currently used by the BS.

DTX_DL: indicator of downlink DTX use.

Output flows: Abis MEASUREMENT RESULT message

Internal flows:

Radio measurements.

Air MEASUREMENT REPORT message (DL) containing DL MS radio measurements.

Uplink radio measurements (quality and level) and a flag indicating whether DTX was used in the downlink (DTX/DL).

Timing advance: last TA calculated by the BTS.

MS_TXPWR_CONF: last reported value of MS power (reported by the MS).

BS_TXPWR_CONF: value of the BS transmit power currently in use.

BFI_SACCH: bad frame indicator of the SACCH block produced every SACCH multiframe (# 480ms):

0 = SACCH frame successfully decoded

1 = SACCH frame not successfully decoded


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1 2 20


Structure of a Measurement Result

CHAN_NUMBER_IEID

FREQ(5) / BSIC(5) / RXLEV_NCELL(6)

Meas_result_number_IEID

Meas_result_number

Element IdentifierLength

{2} / RXLEV_UL_SUB_

{2} / RXQUAL_UL_FULL / RXQUAL_UL_SUB

BS_POWER_IEID

{3} / BS_POWER

Element Identifier

MS_TXPWR_CONF / R{3}

TOA / R{2}

Element Identifier

Length

Length

BA_USED / DTX_UL / RXLEV_DL_FULL

0 / MEAS_VALID / RXLEV_DL_SUB

0 / RXQUAL_DL_FULL / RXQUAL_DL_SUB / NO_NCELL_M

NO_NCELL_M / RXLEV_NCELL(1)

FREQ(1) / BSIC(1)

BSIC(1) / RXLEV_NCELL(2)

RXLEV_NCELL(2) / FREQ(2) / BSIC(2)


RXLEV_NCELL(3) / FREQ(3) / BSIC(3)


0 / Message Type{7}

RXLEV_NCELL(5) / FREQ(5)


SACCH_BFI / DTX_DL{1} / RXLEV_UL_FULL

CHANNEL_NUMBER


MSG_TYPE

MSG_DISK

TI {4} / Prot. Disc{4}


FREQ(6) / BSIC(6)

L1 Info

L3 Info:

Measurementreport from

the MS

Basically, the MEASUREMENT RESULT message is composed of:

L1 info: SACCH Layer 1 header containing MS_TXPWR_CONF and TOA. L3 info: MEASUREMENT REPORT from the MS. This message contains the downlink measurements and

neighbor cell measurements.

Uplink measurements performed by the BTS.

BTS power level used.

SUB frames correspond to the use of DTX:

if the mobile is in DTX, the rxlevsub or rxqualsub is used to avoid measuring the TS where there is

nothing to transmit in order not to distort measurements.

else rxlevfull is used that is to say all TSs are measured.

MS TXPOWER CONF: which is the actual power emitted by the MS.

TOA is timing advance.

SACCH BFI: bad frame indicator; 2 values 0 or 1; 0 means that the BTS succeeded in decoding the

measurement report.

How the neighbor cells are coded:

BCCH1 index in BA list / BSIC1; BCCH2 index in BA list / BSIC2

why? because it does not receive LAC/CI (too long) but BCCH and replies with BCCH/BSIC


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EXtended Measurement Reporting (EMR)

Extended Measurement Reporting mechanisms

Extended Measurement

Order includes theMAFA frequencies theMS is asked to measure

EMO sent onc

Date post:	03-Apr-2018
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