Kite code-based incremental redundancy hybrid ARQ scheme for fast-fading channels  

作　　者：Min Zhu Baoming Bai Jinfang Dou Xiao Ma 

机构地区：[1]State Key Laboratory of Integrated Services Networks,Xidian University [2]National Key Laboratory of Science and Technology on Space Microwave [3]Department of Electronics and Communication Engineering,Sun Yat-sen University

出　　处：《Chinese Science Bulletin》2014年第35期5029-5041,共13页

基　　金：supported in part by the National Basic Research Program of China(2012CB316100);the National Natural Science Foundation of China(61372074 and 61172082);National Key Laboratory Foundation of China(9140C530401120C53201)

摘　　要：Incremental redundancy hybrid automatic repeat request(IR HARQ) has been extensively studied for reliable data transmission over slow-fading or quasi-static channels.With the increase in movement speed of users and the use of long code words for data transmission,IR HARQ strategy in fast-fading channels is starting to attract attention in the academia.This paper studies the performance of the IR HARQ strategy based on Kite codes(a class of rateless codes) in the finite regime over fast-fading channels where a number of channel realizations are experienced in each retransmission round.We propose an algorithm that exploits current decoding reliability to determine the size of subsequent retransmissions.Longterm throughput and delay constraint throughput are analyzed and compared.Furthermore,in HARQ systems available,most of the computation power is consumed on failed decoding if a code word is retransmitted many times,which is not energy-efficient.Therefore,to improve theenergy efficiency,we propose two efficient algorithms(early stopping algorithm and freezing node algorithm) for incremental decoding,which reduce the computational complexity of the most time-consuming steps in decoding procedure.Simulation results show that the substantial complexity reduction is achieved in terms of the total required number of decoding iterations and the required node operation complexity compared to conventional incremental decoding scheme.Incremental redundancy hybrid automatic repeat request （IR HARQ） has been extensively studied for reliable data transmission over slow-fading or quasi-static channels. With the increase in movement speed of users and the use of long code words for data transmission, IR HARQ strategy in fast-fading channels is starting to attract attention in the academia. This paper studies the perfor- mance of the IR HARQ strategy based on Kite codes （a class of rateless codes） in the finite regime over fast-fading channels where a number of channel realizations are experienced in each retransmission round. We propose an algorithm that exploits current decoding reliability to determine the size of subsequent retransmissions. Long- term throughput and delay constraint throughput are ana- lyzed and compared. Furthermore, in HARQ systems available, most of the computation power is consumed on failed decoding if a code word is retransmitted many times, which is not energy-efficient. Therefore, to improve theenergy efficiency, we propose two efficient algorithms （early stopping algorithm and freezing node algorithm） for incremental decoding, which reduce the computational complexity of the most time-consuming steps in decoding procedure. Simulation results show that the substantial complexity reduction is achieved in terms of the total required number of decoding iterations and the required node operation complexity compared to conventional incremental decoding scheme.

关 键 词：HARQ 衰落信道 增量 冗余 风筝 混合自动重复请求 数据传输速度 计算复杂度 

分 类 号：TN92[电子电信—通信与信息系统]