01 CDMA Overview

Customer Service Department of CDMA Division

Internal Use Only ▲CDMA Basic Theory

CDMA Overview CDMA Basic Principle CDMA Channel Structure and Function CDMA Key Technology


Internal Use Only ▲

I. CDMA Overview


Internal Use Only ▲Objectives

Upon completion of this lesson, the students

will be able to master: -- the history of mobile communication

-- the advantage of CDMA

-- CDMA migration from 2G to 3G

-- CDMA spectrum usage

-- the role of ZTE in CDMA



• Mobility：– flexible and convenient， global personal

communication• Poor environment and conditions ：

– Co-channel interference, multi-path(space and time), power change and other noise

• Multiple MS and channels：– Interference 、 near and far effect

• Limit of frequency resources• Reliability is important

– registration, handoff, switching

Characteristics of Mobile Communication



11GG 22GG 33GG

Analog cellular

DDiiggiittaall cceelllluullaarr DDiiggiittaall cceelllluullaarr

VVooiiccee VVooiiccee //ddaattaa VViiooccee // hhiigghh ssppeeeedd ddaattaa

AAMMPPSS CCDDMMAA 11XXRRtttt CCDDMMAA22000000

TTAACCSS GGSSMM GGPPRRSS WW__CCDDMMAA

8800’’ 11999922 11999999 22000011 22000033

Evolution of Mobile Communication System

AMPS: Advanced Mobile Phone SystemTACS: Total Access Communication SystemGPRS: General Packet Radio Services


Internal Use Only ▲CDMA-Its History & Status

• 1993, the first CDMA standard IS-95 was issued;• In 1995, CDMA technology was put into commercialization in Hong

Kong and America on large scales;• In 1997, CDMA trial networks were constructed in Beijing, Xian,

Shanghai and Guangzhou in China;• In April, 2001, China Unicom began to construct CDMA networks—the

largest in the world;• At present, CDMA commercial networks are established in about 40

countries or area, almost 20% of all users in the world.



Frequency reuse factor is 1;network design and expanding become much easier

Frequency reuse factor is 1;network design and expanding become much easier

Advantages of CDMA(1)

AMPS, D-AMPS, N-AMPS

CDMA

30 30 10 kHz

200 kHz

1250 kHz

1 3 1 Users

8 Users

20 Users1

1

11

1

11

11

1

11

1

1

12

34

43

2

56

17

Typical Frequency Reuse N=7



Vulnerability:C/I 17 dB

Vulnerability:C/I 12-14 dB

Vulnerability:Eb/No 6--7 dB

GSM



Large capacity:8--10 times than AMPS4—6 times than GSM

Large capacity:8--10 times than AMPS4—6 times than GSM

FrequencyTime

Power

FrequencyTime

Power

FrequencyTime

Power

FDMA

TDMA

CDMA

FDMA---Different user use different frequency

TACS 、 AMPS

TDMA---Different user use different time slot of one frequency

GSM 、 DAMPS

CDMA---Different user use same frequency at the same time,but with different spreading code




large coveragealmost 2 times than GSM, save money for operator

large coveragealmost 2 times than GSM, save money for operator

Example:cover 1000 km2： GSM need 200 BTS CDMA only need 50 BTS Attention: exact result need “Link Budget ”

Example:cover 1000 km2： GSM need 200 BTS CDMA only need 50 BTS Attention: exact result need “Link Budget ”




High privacy and hard to wiretappingHigh privacy and hard to wiretapping

Spread code

Informationsignal

TX

Demodulatedsignal

RX

Spread code

Spread signalEach user is below the noise deeply




CDMA ：” make before break”---soft handoffOther systems: “make after break”---hard handoff

CDMA ：” make before break”---soft handoffOther systems: “make after break”---hard handoff

Use soft handoff: decrease drop-call rateUse soft handoff: decrease drop-call rate




Perfect Power Control and voice activation make the MS

Power low, healthy for human body—green mobile phone.

Perfect Power Control and voice activation make the MS

Power low, healthy for human body—green mobile phone.


Mean Power Max Power

GSM: 125mW 2W

CDMA: 2mW 200mW

Mean Power Max Power

GSM: 125mW 2W

CDMA: 2mW 200mW



95A 95B Software update Replace MS to

get new service

95B 1X Add 1X channel

board Software update Replace MS to get

new service

1X 1XEVDO

Add the new equipment

TechnicalScheme ：

Smooth migration to 3G and the operators’ benefit is protected at the most

Smooth migration to 3G and the operators’ benefit is protected at the most

Almost free inexpensiveEconomicScheme ：



Internal Use Only ▲Definition of Some Terms（ 1）

• Channel– Duplex channel made of two 1.2288MHz-wide bands of electromagnetic

spectrum: one for Base Station to Mobile Station communication (called the

FORWARD LINK or the DOWNLINK) and another for Mobile Station to Base Station communication (called the REVERSE LINK or the UPLINK)

• Carrier or Frequency– In 800 MHz Cellular ,these two duplex 1.25 MHz bands are 45 MHz apart;– In 1900 MHz PCS ,they are 80 MHz apart ;– In 450MHz,they are 10MHz apart ;

45 or 80 or 10 MHz

CDMA CHANNELCDMA

ReverseChannel 1.25 MHz

CDMAForwardChannel 1.25 MHz



CDMA Frequency Calculation：

450MHzBS receiver(Uplink): 450.00+0.025(N-1) BS sender(downlink): 460.00+0.025(N-1)

800MHzBS receiver(Uplink): 825.00+0.03NBS sender(downlink):870.00+0.03N

1900MHzBS receiver(Uplink): 1850.00+0.05NBS sender(downlink):1930.00+0.05N

Definition of Some Terms（ 2）


Internal Use Only ▲CDMA 800 MHz Cellular Spectrum Usage

• All CDMA RF carriers are 1.25 MHz. wide– Can serve ~20 users /8 kb vocoder

Possible CDMA Center Freq. Assignments

Channel Numbers

Forward link (i.e., cell site transmits)Reverse link (i.e., mobile transmits)824MHz

849MHz

869MHz

894MHz

otherusesA” A”A B A’ B’

1 10 10 1.5 2.5

A B A’ B’

1 10 10 1.5 2.5

991

10231 333

334

666667

716717

799

991

10231 333

334

666667

716717

799

~300 kHz. “guard bands” possibly required if adjacent-frequency signals are non-CDMA (AMPS, TDMA, ESMR, etc.)


Internal Use Only ▲CDMA Frequency ChannelAssignment at 800 MHz Cellular

IS-95 Recommends to Start CDMA deployment with Either the Primary or the Secondary Channel

1

334

667

991

1023

333

666

715

799

716

ChannelNumbers

A Band B Band A’A” B’

1019 37 78 119 160 201 242 283 384 425 466 507 548 589 630 691 777

CDMA A-Band Carriers CDMA B-Band Carriers

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 9 9 8

* **** Requires frequency coordination with

non-cellular interferers

** Requires frequency coordination with A-band carrier

A Band Primary Channel 283A Band Secondary Channel 691

B Band Primary Channel 384B Band Secondary Channel 777

736


Internal Use Only ▲ZTE’s Activities in CDMA

In 1995, CDMA mobile telecommunication project started. In November, 1999, ZTE signed the “Agreement on CDMA” with Qualcomm. In August, 2000, the first field trial was set up. In September, 2000 , ZTE presented the first CDMA handset with UIM

in the world. In January, 2001, the first cdma2000-1x call was passed through in lab. In March, 2001, ZTE cdma2000-1x realized the integrated transmission of

voice, data & image.The data rate reached up to 153.6Kbps.

The certificates acquired:–CDMA 800M ZXC10-MSC/VLR, HLR/AUC,BSC, BTS network access licenses–CDMA 450 M/800M/1.9G ZXC10-BTS type approval certificates


Internal Use Only ▲ ZTEA Famous Brand in CDMA

2G/3G 终端

Abis

Abis

Abis

PSTN/PLMN

BSC/ PCF (1X)

Internet

路由器路由器IP

IP

BTS（ IS-95）

BSC（ IS-95）

Abis

E1Um

IS95

Um

IS2000E1 STM-1

E1 STM-1

Ethernet

MSC/VLR HLR/AUC

PDSN/FA

AAA

HA

OMC

SC

WINBTS（ IS-

95）

BSC/ PCF (1X)

BTS（ 1X）

BTS（ 1X）

E1

业务服务器

Ethernet

Date post:	05-Mar-2015
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01 CDMA Overview

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