AMC+Edge英文基础知识.pptx
Wireless Mobile Communication and Transmission Lab.(WMCT)1Adaptive Modulation and CodingDec.3,2013Basic principles,Techniquesand ApplicationsWireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive Modulation and CodingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive Modulation and Coding2Wireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive Modulation and CodingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive Modulation and Coding3Wireless Mobile Communication and Transmission Lab.(WMCT)Introduction Introduction of Adaptive of Adaptive Modulation Modulation and and CodingCodingqAdaptive Modulation and Coding(AMC):Change modulation and coding relative to the Channel State Information(CSI)qParameters to adapt:Constellation sizeTransmit powerInstantaneous BERSymbol timeCoding rate/schemeqOptimization criterion:Maximize throughputMinimize average powerMinimize average BER4Wireless Mobile Communication and Transmission Lab.(WMCT)Main Applications of AMCqHigh Speed Downlink Packet Access(HSDPA)qWireless Local Area Networks(WLAN)qWorldwide Interoperability for Microwave Access(WiMax,802.16)q3GPP Long Term Evolution(LTE,3.9G)5Wireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive Modulation and CodingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive Modulation and Coding6Wireless Mobile Communication and Transmission Lab.(WMCT)Adaptive Transmission System7System modelWireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive modulation and codingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive modulation and coding8Wireless Mobile Communication and Transmission Lab.(WMCT)Adaptive TechniquesqRate Control Fixing symbol rate，using multiple modulation schemes or constellation sizesnFairly easy,used in current systems,such as GSM,IS-136 EDGE or 802.11a,et.al.Fixing the modulation,changing the symbol ratenVarying signal bandwidth is impractical and complicates bandwidth sharing.qPower ControlAdapting the transmit power alone is generally used to compensate for SNR variation due to fading.To maintain a fixed bit error probability,or a constant received SNR.The power adaptation thus inverts the channel fading so that the channel appears as an AWGN channel to the modulator and demodulator.9Wireless Mobile Communication and Transmission Lab.(WMCT)Adaptive TechniquesqError ControlAdapt the instantaneous BER subject to an average BER constraint.nNot an adaptive technique,since the transmitter does not adapt to SNR.Error probability is typically adapted along with some other form of adaption such as constellation size or modulation type.qCoding ControlIn adaptive coding different channel codes are used to provide different amounts of coding gain to the transmitted bits.Adaptive coding can be implemented by multiplexing together codes with different error correction capabilities.An alternative technique to code multiplexing is rate-compatible punctured convolutional(RCPC)codes.10Wireless Mobile Communication and Transmission Lab.(WMCT)Adaptive TechniquesqHybrid techniquesAdapt multiple parameters of the transmission scheme,including rate,power,coding,and instantaneous error probability.Joint optimization of the different techniques is used to meet a given performance requirement.Rate adaption is often combined with power adaptation to maximize spectral efficiency.11Wireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive modulation and codingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive Modulation and CodingqAMC for multi-userqEDGE12Wireless Mobile Communication and Transmission Lab.(WMCT)Application of AMC13qAMC for multi-userDownlink transmission format is adapted to different SNRnUsers with high SNR:use MQAM(large M)+high code ratesnUsers with low SNR:use BPSK+low code ratesDifferent user get a different rateHigh-speed shared ChannelChannel quality(CQI,Ack/Nack,TPC)Wireless Mobile Communication and Transmission Lab.(WMCT)ADC for multi-user14Wireless Mobile Communication and Transmission Lab.(WMCT)ADC for multi-user15qAMC for multi-userLower data rates are achieved by using a small constellation such as QPSK and low rate error correcting codes such as rate 1/2 convolutional or turbo codes.The higher data rates are achieved with large constellations such as 64QAM and less robust error correcting codes,for example rate 3/4 convolutional,turbo,or LDPC codes.Wireless Mobile Communication and Transmission Lab.(WMCT)ADC for multi-user16qAMC vs Shannon LimitnOptionally turbo-codes or LDPC codes can be used instead of simple block/convolutional codes in these schemesWireless Mobile Communication and Transmission Lab.(WMCT)OutlineqIntroduction of Adaptive modulation and codingqAdaptive Transmission SystemqAdaptive TechniquesqApplication of Adaptive modulation and codingqAMC for multi-userqEDGE17Wireless Mobile Communication and Transmission Lab.(WMCT)Introduction of EDGEqEDGE=Enhanced Data rates for GSM(or Global)EvolutionqEDGE包括EGPRS和ECSDqEGPRS是对GPRS的增强，对系统的影响主要包括：在RF层采用了8PSK调制方式，极大提高了单信道的速率对链路层RLC/MAC做了修改，并且定义了更完善和链路控制算法18Wireless Mobile Communication and Transmission Lab.(WMCT)Key techniques of EDGEq8-PSK 调制解调q多种编码方式（MCS19)q链路质量控制（LQC）链路自适应（LA）递增冗余重传（IR）19Wireless Mobile Communication and Transmission Lab.(WMCT)GMSK and 8PSK Modulation20q与GMSK相同的符号率，但比特率可提高三倍符号率：270.833 ksymb/s时隙比特率：GMSK：0 22.8 kbit/s 8PSK：0 69.6 kbit/sGPRSEDGEModulationGMSK8-PSK/GMSKSymbolrate270ksym/s270ksym/sModulationbitrate270kb/s810kb/sRadiodataratepertimeslot22.8kb/s69.6kb/sMaxuserdataratepertimeslot20kb/s59.2kb/sMaxuserdatarate(8timeslots)160kb/s473.6kb/sWireless Mobile Communication and Transmission Lab.(WMCT)GPRS与与EDGE信道编码信道编码21Wireless Mobile Communication and Transmission Lab.(WMCT)q链路质量控制（LQC）所谓链路质量控制，就是指在数据传输过程中通过改变调制方式和编码方式，动态地适应无线传输环境，以达到提高链路质量的方法。EDGE采用了一套精心设计的、高效的链路质量控制算法，定义二种链路质量控制模式，链路适配LA（link adaption）和增量冗余IR（Incremental Redundancy）。qLQC特点估算链路质量选择MCS分割Link Quality Control(LQC)22LALAIRIR8PSK8PSKGMSKGMSKWireless Mobile Communication and Transmission Lab.(WMCT)Evolution of EDGE23Wireless Mobile Communication and Transmission Lab.(WMCT)Application value of EDGEqEDGE能够承载的无线数据业务分析从速率的角度来看：GPRS：4 时隙速率50kbps 左右EDGE：4 时隙速率150kbps左右qEDGE不但能够承载全部GPRS业务，而且已经能够承载许多更为先进的移动数据业务，这些服务包括：在线游戏大容量文件的传输视频短片的下载音乐的下载流媒体的音视频业务高速的互联网接入等等24Wireless Mobile Communication and Transmission Lab.(WMCT)25ANY ANY QUESTIONS?QUESTIONS?
