CDMA System Basis

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.

Classification of Wireless Telecomm

Frequency Reuse

Evolution of Wireless Telecomm

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

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

Signal processing by DSSS

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

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

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

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

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

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

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

IS-95A Channel Modulation--Forward Link

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

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

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

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

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

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