1. CDMA System Basis

2. Features of Wireless Telecomm
Individually
Bad propagation environment
Co-channel, Adjacent channel interference and near-far effect.
Contradiction between limited frequency resource and vast numbers of subscribers.
Complicated network and control equipment are required.

3. Classification of Wireless Telecomm

5. Frequency Reuse

6. Evolution of Wireless Telecomm

7. Makeup of Wireless Telecomm
BSS
MS: Mobile Station
BSS: Base Station System
BTS: Base-station Transceiver System
BSC: Base_Station Controller
MSC:Mobile-service Switching Center
VLR:Visiting Location
Register
HLR:Home Location Register
PSTN:
ISDN: MS
BTS
BTS
BSC
VLR
BTS MS
HLR
MSC
PSTN MS
ISDN
BTS
BSC
BTS
BTS MS Um
Abis A
MSC

8. Spectrum Spreading Technique
Theoretical Basis is Shanon equation C=B*log2(1+S/N)
DSSS applied in CDMA
Used in military communication in 1950’s and 1960’s
Qualcomm company successfully put it into commercially cellular wireless telecommunication by the end of 1980’s

9. Signal processing by DSSS

10. Features of CDMA System（1）
Large capacity
8~10 times of analog system
High-quality service
8Kb/s QCELP EQUALS 13Kb/s of GSM;
13Kb/s QCELP EQUALS 64kb/s of wireline
Soft handoff lowers call drop rate
RAKE receiving overcomes multi-path fading
Good secrecy

11. Features of CDMA System （2）
Soft capacity
MS’s averaging transmission power is lowered, decreasing radiation to human body and environment . Be named as “Green Handset”
Easy to realize dual-mode operation
System complexity increased

12. Key techniques of CDMA （1）
Diversity receiving
Time diversity——interleaving, error-detection and correction
Frequency diversity——inherent feature of wideband communication
Space diversity——multiple antenna receiving, RAKE receiving, soft handoff

13. Key techniques of CDMA （2）
Precise power control
Open loop power control on reverse link
Closed loop power control on reverse link
Outer loop power control on reverse link
Power control on forward link

14. Key techniques of CDMA （3）
Rate variable codec (QCELP)
VOICE Detection (VOD)
Synchronization
Mobile assisted soft handoff

15. Key techniques of CDMA （4）
Blossoming & Wilting
Low Eb/No and high redundant error correction encoding
Multiple access：long PN code, short PN code and WALSH orthogonal code

16. Channel structure Forward Channels Piloting channel Reverse Channels
Synchronizing channel
Paging channel
Traffic channel
Reverse Channels
Access channel

18. IS-95A Channel Modulation--Forward Link

19. Procedure of MS’s COMMUNICATION
Searching base station’s pilot channel
Demodulating synchronizing channel
MS requests on access channel
BS responds on paging channel
Traffic channel is assigned for communication

20. MS idle status System access status MS Initial Status
Power On MS
Initial
Status
MS idle status
System access
status
MS in traffic
Channel
MS fully catches
System timing
MS paged, originating or registering
MS idle changeover when NGHBR_CONFIG is”011”
Access channel confirmation
End traffic channel
Indication of traffic channel
Task Initialization
Start analog mode
End analog mode
Notes：not all are listed out

21. ZXC10-BSS System structure-BSC
BSC: Base_Station Controller
BTS: Base-station Transceiver System
NCM: Network Control Module
HIRS: High-speed Interconnect Router Subsystem
CDSU: Channel/Digital Service Unit
TCM: Timing Control Module
SVM: Selector Vocoder Module
SVICM: Selector Vocoder Interface Control Module
CPM: Call Process Module
OMC: Operation & Maintenance Center

22. ZXC10-BSS System structure-BTS
BTS: Base-station Transceiver System
CHM: Channel Processing Module
CCM: Communication Control Module
HIRS: High-speed Interconnect Router Subsystem
TCM: Timing Control Module
RFIM: RF Interface Module
TRx: Transceiver
HPA: High Power Amplifier
RFE: RF Front End
CDSU: Channel/Digital Service Unit
BTM: Base-station Test Module
BSC: Base-station Controller

23. ZXC10_BSS System Specification-BSC
Maximal BTS supported: 512
Vocoder：7200
Maximal Channels (including payoff and soft handoff):512 X 32 = 16384
Maximal traffic channels: 512 X 20 = 10240
Maximal subscribers: 102,500*
BTS side traffic：2,930 Erl*
BHCA：125,000*
Traffic：1.28BHCA/subscriber

24. ZXC-10 BSS-transition to 3G
Features:
Capacity increased
Non-symmetrical data service provided
For:64Kb/s
Rev:14.4Kb/s
Backward compatible with 95A
Capacity doubled (relative to 95A)
Data service
144Kb/s
307.2Kb/s(max)
Backward compatible with 95A/B
Data service
384Kb/s
2Mb/s(max)
Backward compatible with 95A/B/1X