Theoretical Research And Queuing Performance Analysis Of The Automatic Repeat Request Protocols In Wireless Communication Link

This thesis is concerned with the delay performance of Automatic Repeat Request (ARQ)protocols,which are the important error-control technologies to guarantee the reliable data transmission in the link of wireless communication.As the significant error-control technologies,the main disadvantages of basic ARQs are that the system's delay will increase fast and the throughput will decreases quickly when the error probability of the channel increases(such as in the satellite communications link), especially when the roundtrip delay is large.So how to conquer the multi-path fading and the shadow fading in the radio mobile conditions,and how to improve the transmission efficiency of ARQ scheme to ensure the high reliable data transmission are becoming the study focuses.For that this paper mainly refers to one of the important system efficiency indicators:the system delay performance.In this thesis the delay performance indicator of the ARQ and adaptive GBN-ARQ and so on are studied deeply by modeling.The main works and innovations of this dissertation are generalized as follows(in the chapter 3th and chapter 4th):Firstly,by analyzing the transmission mechanisms of the basic ARQ and the hybrid ARQ protocols,the basic queuing delay performance of the standard GBN-ARQ system is modeled and studied based on the vacation queuing theory,as a result the formulations of mean packet waiting delay and mean packet service delay,which are the main delay performance indicators,are educed with the effect analysis of the sliding windows length,packet length and the packet error probability on the system delay performance; Also the theoretical model study and numerical simulation validation for the existence and confirmation of the optimum sliding window length and the optimum packet length are given based on the delay model.Secondly,taking account of the random dividing behavior of arrival message on the transmission station and the different conditions between the forward channel and the feedback channel,the extending queuing delay models for the transmission process of both SGBN-ARQ and SR-ARQ systems are obtained,that is,a queuing model with packets batch-arrival denoted by M^[X]/G/1. Further more,the formulations of mean packet service delay and unitary maximum throughputs of both systems are deduced and are analyzed by simulations.And a conclusion that in the same conditions the delay performance of SGBN-ARQ can be close to the SR-ARQ's by the adaptively change of sliding window length without enhancing the implementation complexity is made.A step study of the existence and confirmation of optimum sliding window length of both systems are carried on through theatrical analyses and simulation validation.Lastly,by analyzing the general single-mode automatic-repeat-request GBN-ARQ schemes,an adaptive two-mode (with continuous GBN-ARQ scheme and n-copy GBN-ARQ scheme)AGBN-ARQ scheme is presented,where the forward channel is assumed for Gilbert-Elliott channel mode and the feedback channel is for a noise channel,and channel state estimation is based on counting the continually received ACK/NAK acknowledgements.Then semi-Markov chain of the adaptive transmission with(α+β)states is established and the more exact steady-state distributions are gained;Also,taking account of the packet length,the queuing delay model of the adaptive scheme with packets batch arrivals is built as well as the formula of average packet service delay of the adaptive scheme is given.Meanwhile,it's approved that the adaptive two-mode AGBN-ARQ scheme has better system delay and throughput performances than both continuous GBN-ARQ and n-copy GBN-ARQ schemes.