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 th...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.展开更多
This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous work...This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous works on this topic, the present development and the performance analysis as well, is based on rate compatible punctured turbo codes. Rate compatibility provides incremental redundancy in transmission of parity bits for error correction at the data link layer. Turbo coding and iterative decoding gives lower packet error rate values in low signal-to-noise ratio regions of the adaptive modulation and coding (AMC) schemes. Thus, the applied cross-layer design results in AMC schemes can achieve better spectral efficiency than convolutional one while it retains the QoS requirements at the application layer. Numerical results in terms of spectral efficiency for both turbo and convolutional rate compatible punctured codes are presented. For a more comprehensive presentation, the performance of rate compatible LDPC is contrasted with turbo case as well as the performance complexity is discussed for each of the above codes.展开更多
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)
文摘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.
文摘This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous works on this topic, the present development and the performance analysis as well, is based on rate compatible punctured turbo codes. Rate compatibility provides incremental redundancy in transmission of parity bits for error correction at the data link layer. Turbo coding and iterative decoding gives lower packet error rate values in low signal-to-noise ratio regions of the adaptive modulation and coding (AMC) schemes. Thus, the applied cross-layer design results in AMC schemes can achieve better spectral efficiency than convolutional one while it retains the QoS requirements at the application layer. Numerical results in terms of spectral efficiency for both turbo and convolutional rate compatible punctured codes are presented. For a more comprehensive presentation, the performance of rate compatible LDPC is contrasted with turbo case as well as the performance complexity is discussed for each of the above codes.
