中英文对照的cdma95标准

THE IS-95 Standards IS-95 标准,Overview综述,THE IS95 Standards IS95 标准Spectrum and Frequency Plans 频谱和频率分配方案A CDMA SystemCDMA 系统Logical Data Channels 逻辑数据信道Forward Link Structure 前向链路结构Reverse Link Structure反向链路结构Codes 编码Power Control 功率控制Handoff 切换CDMA Call Processing CDMA呼叫处理,Major IS95 Standards主要的IS95标准,Cdma20001xRTT and packet data. Backwards compatible with IS95B 1xRTT及打包数据，后台与IS95B兼容IS95A/Bradio interface specification (also called TIA/EIA95） 无线接口说明（也称为TIA/EIA95）IS96A8 kbps speech service option 8kbps的语音服务选项IS97BTS Minimum Performance Standards 基站最低性能标准IS98MS Minimum Performance Standards 手机最低性能标准IS127EVRC Speech Service Option EVRC语音服务选项IS634AOpen A Interface (MSC to BSC) 开放A接口（MSC至BSC）IS707APacket Data 打包数据IS-73313 kbps Speech service option 13 kbps的语音服务选项IS-637Short Message Service 短信息服务IS-638Over-the-air activation and parameter administration 无线激活和参数管理,Spectrum Allocations频谱分配,Same duplex bands as AMPS与AMPS相同的双波段2x20 MHz (excluding the extension bands A, B and A) 2x20 MHz（除了扩展波段A、B和A”之外）A CDMA channel centre frequency is given by: CDMA信道中心频率来自：825 + n*0.03 MHz (Reverse Link, MS to BTS)825 + n*0.03 MHz （反向连接，手机到基站）870 + n*0.03 MHz(Forward Link, BTS to MS)870 + n*0.03 MHz（前向连接，基站到手机）Each CDMA Carrier occupies 1.25MHz (x2)每个CDMA载波占用1.25MHz（ x2 ）,1.25,825,845,MHz,1.25,1.25,1.25,870,890,MHz,1.25,1.25,Reverse Link反向链路,Forward Link前向链路,Primary and Secondary Carriers主要和次要载波,These channels fall in the AMPS Extension Bands 这些频道在AMPS扩展波段之内,Only Primary and Secondary carriers are specified in IS95. Other carrier frequencies are defined by the operator. IS95中只规定了主要和次要载波。其他载波频率由运营商定义。,CDMA Frequency PlansCDMA 频率分配方案,IS-95 is really CDMA/FDMA. IS-95 是真正的CDMA/FDMA。Each 1.25 MHz “Carrier” or Frequency Allocation (FA) can support approx 20-30 simultaneous users (depending on various factors). 每1.25兆赫兹的“载波”或频率分配（FA）可同时支持大约20到30个用户（取决于各种因素）。Codes are used within each carrier to distinguish users 每个载波都用代码识别用户Initially all sectors on all base station use a common 1.25MHz Carrier. 开始时，所有基站的所有扇区都共用1.25兆赫兹载波Additional carriers are added per site as traffic increases. 随着话务量的增长增加其它载波,7/21, 4/12 etc,N=1,GSM / AMPS etc,CDMA,Code 1,Code 2,Code 3,Code 4,Code N,Frequency 1频率1,Code 1,Code 2,Code 3,Code 4,Code N,Frequency 2,A CDMA System,Reverse Link反向链路,Forward Link前向链路,BTS,BTS,Base Station Controller (BSC)基站控制器（BSC）,Mobile Station (MS)移动电话,Mobile Switching Center (MSC)移动交换中心（MSC）,PSTN,Vocoders声码器,HLR, VLR,Vocoders声码器,Vocoders convert analog speech (bandwidth 3 kHz) to a low bit-rate digital signal suitable for transmission over a mobile system (typically, 8 kbps or 13 kbps).声码器将模拟语音（带宽3千赫兹）转换成适合移动系统（通常速率为8kbps或13kbps）传输的低比特率数字信号。Waveform coders sample a signal and transmit a replica of the signal. Examples include G.703 (64 kbps), G.721 32 kbps ADPCM used for PSTN.波形编码器对信号取样并发送一个与该信号相同的复制信号。例如用于PSTN的G.703 (64 kbps)、 G.721 32 kbps ADPCM 。Vocoders perform a parametric modelling of human speech and transmit parameters describing the input signal. These parameters are used to regenerate the original signal.声码器将人类语言进行参数模拟并传输这些参数来描述这些输入信号。这些参数被用来还原原始信号。,Speech Vocoders语音声码器,Vocoder声码器,Demodulation解调,PSTN,8 kbps (或 13 kbps),Modulation调制,Vocoder声码器,64 kbps PCM 或 32 kbps ADPCM,3 kHz,8 kbps (或 13 kbps),BTS,Coding and decoding introduce delay 编码和解码导致时延Delays 64Block. Enc,Long PN code gen.,Short PN code gen.,28.8 ksps,307.2 ksps,1.2288 Mcps,1.2288 Mcps,RF,W = 1.25 MHz,ESN addressmask,Data Coding (x32),x4 spreading,x1 Spreading (randomisation),Detailed Reverse Link Structure反向链路详细构造,R=1/3 Encoding and RepetitionR=1/3解码和重复,Block Inter-leaver块交织器,To RF,9600,4800,2400,1200 bps,19.2 ksps,307.2 ksps,1.2288 Mcps,Q Short Code,I Short Code,6-64Block. Enc6-64解码,19.2 ksps,1.2288 Mcps,1/2 chip delay,Long PN Code Generator长PN编码发生器,ESN based Mask (42 bits)基于ESN的掩码（42位）,1.2288 Mcps,x4 spreadingX4扩展,Data Coding (x32 to x256)数据编码(x32 to x256),x1 Spreading (randomisation)X扩展（随机）,Punct-ure击穿,Decimate分样,Reverse Link RF反向链路RF,1.2288 Msps,Q Short CodeQ短编码,I Short Code,1.2288 Mcps,1.2288 Mcps,cos(wct),sin(wct),HPA,I,1/2 chip delay集成电路继电器,FIR FilterFIR滤波器,FIR FilterFIR滤波器,Why Offset QPSK?为何QPSK会产生分支Using the chip delay, 180 phase transitions are avoided.使用1/2码片延时可避免180度相变When passed through a non-linear amplifier (eg a mobile PA), OQPSK exhibits less spectral regrowth than QPSK.当经过一个非线性放大器（如移动PA）后，OQPSK的频谱再生比QPSK小,IS-95 Reverse LinkIS-95反向链路,Rate 1/3 convolutional + rate 6/64 Block data coding is effectively rate 1/32 convolutional encoding1/3率的卷积编码加上6/64率的块编码效果相当于1/32率卷积解码。Block encoding done with Walsh functions 用沃尔什函数完成块解码Each 6 data bits selects 1 of 64 Walsh functions (each 64 symbols long)每6个数据位选择64个沃尔什函数之一（每个长64码元）Allows non-coherent detection (i.e Wn or +Wn map to the same 6 bit data sequence)可进行非连贯性检测（例如Wn或+Wn对应同样的6位数据序列） Long PN performs x4 spreading to final 1.25 MHz bandwidth. 长PN实现x4扩展至最终的1.25MHz带宽。Repeats every 42 days! 每42天重复一次Unique phase (offset) per mobile 每个受机都有特定的相位（偏移）Short PN code randomises (but no spreading). 短PN编码是随机的（但不扩展）Repeats every 26.6667 ms每26.6667毫秒重复一次,IS95 CodesIS95代码,The Short Codes短代码,Only two short codes are used in IS95 (I and Q channels)只有两种短代码用于IS95中（I和Q信道）Maximal length sequences, with 1 additional bit 最大长度序列，带一个附加位length = 215 = 32,678 chipsThe offset, or phase, of the code is used to discriminate between sector transmissionsAll BTS sectors transmit a pilot, which is unmodulated I and Q short codes代码的偏移或相位用于区分小区传输。所有的BTS小区发送一个导频，该导频为未调制的I和Q短代码used by mobiles to identify sectors for handoff用于手机切换时识别扇区There are 512 allowable offsets (i.e every 64 chips)有512个可用的偏移（例如每64个芯片）,Synchronisation 同步,Pilot signal (short codes only) radiated from each BTS sector 每个BTS扇区广播导频信号（仅限于短代码）。Typically Pilot power = 15% of maximum transmission power通常的导频功率=最大传输功率的15%Same code is used for all sectors but with different offsets, providing discrimination between sectors and BTS. 同一个代码 可用于所有的扇区，但带有不同的偏移，以区分不同的扇区和BTS。 GPS supplies tight Pilot timing ( T_ADDCandidate Pilot Active Pilot + T_COMP,Neighb