The Research On ARQ Protocol In Packet Transmission System Over Fading Channels

The transmitted signals in wireless communication system are heavily deterioratedby channel fading. In order to enhance communication reliability and increase systemthroughput., a lot of new technology has been proposed. Hybrid ARQ and cooperativecommunication with Alamouti Space-Time Codes are effective measures to combatchannel fading. This dissertation studies the performance for the packet transmissionover fading channels based on the PER analysis, the throughput performance for ARQtechnique, the PER analysis for Alamouti Space-Time Codes, and the the performanceof the hybrid ARQ technique of the3G-HF High-Rate Data Link Protocol. The maincontributions of this dissertation are concluded as follows:Firstly, this dissertation studies the average PER performance for the packettransmissions over Rician fading channels. We extend the existing work for the PERanalysis on Rayleigh fading to Rician fading. With the concept of ‘inverse coding gain’,We develop a simple and rather accurate method to evaluate the average packet errorrate in high SNR region for an uncoded packet transmission system over Rician fadingchannels. Then, we develop an approximation calculation for the inverse coding gainwith large packet length. It is proved that the inverse coding gain generally follows anapproximately linear relationship with the logarithm of the packet length, when the BERof the system under AWGN has the Gaussian Q-function form, e.g., for BPSK, QPSK,M-PAM and etc. Extensive simulation results validate our theoretical analysis.Secondly, based on some conclusions of the first chapter, we studies the throughputperformance for stop-waiting ARQ system over fading channels. For Rayleigh fading, asimple expression for the optimal packet length to maximize the average throughput isobtained. Extensive simulation results validate our theoretical analysis.Thirdly, this dissertation studies the PER performance for the AlamoutiSpace-Time Codes with conventional modulation over Rayleigh fading channel andobtain the expression. Extend the conclusion to the system with diversity order is N.Fourth, the dissertation propose a measure which combine the AlamoutiSpace-Time Codes with the hybrid-ARQ technique. Then discuss the average PER andthroughput performance of the system over fading channels.At last, study the performance of the3G-HF High-Rate Data Link Protocol (HDL)based on the standard which defined in U.S. MIL-STD-188-141B.Considering thedifferent conditions, we discuss the bit error rate, packet error rate, average transmissiontimes and throughput performance by simulations and theoretical analysis.