01 cdma overview
TRANSCRIPT
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
Customer Service Department of CDMA Division
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
Customer Service Department of CDMA Division
Internal Use Only ▲
• 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
Customer Service Department of CDMA Division
Internal Use Only ▲
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
Customer Service Department of CDMA Division
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.
Customer Service Department of CDMA Division
Internal Use Only ▲
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
Typical Frequency Reuse N=4
Typical Frequency Reuse N=1
Vulnerability:C/I 17 dB
Vulnerability:C/I 12-14 dB
Vulnerability:Eb/No 6--7 dB
GSM
Customer Service Department of CDMA Division
Internal Use Only ▲
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
Advantages of CDMA(2)
Customer Service Department of CDMA Division
Internal Use Only ▲
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 ”
Advantages of CDMA(3)
Customer Service Department of CDMA Division
Internal Use Only ▲
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
Advantages of CDMA(4)
Customer Service Department of CDMA Division
Internal Use Only ▲
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
Advantages of CDMA(5)
Customer Service Department of CDMA Division
Internal Use Only ▲
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.
Advantages of CDMA(6)
Mean Power Max Power
GSM: 125mW 2W
CDMA: 2mW 200mW
Mean Power Max Power
GSM: 125mW 2W
CDMA: 2mW 200mW
Customer Service Department of CDMA Division
Internal Use Only ▲
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 :
Advantages of CDMA(7)
Customer Service Department of CDMA Division
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
Customer Service Department of CDMA Division
Internal Use Only ▲
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)
Customer Service Department of CDMA Division
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.)
Customer Service Department of CDMA Division
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
Customer Service Department of CDMA Division
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
Customer Service Department of CDMA Division
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