To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder...To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder to improve its performance at short interleaving delay. The combination of Log MAP and SOVA avoids updating the matrices of the maximum path, and also makes a contribution to the requirement of short delay. The simulation results of several SCCCs show that the improved decoder can obtain satisfied performance with short frame interleaver and it is suitable to the high bit rate low delay communication systems.展开更多
In most practical quantum mechanical systems,quantum noise due to decoherence is highly biased towards dephasing.The quantum state suffers from phase flip noise much more seriously than from the bit flip noise.In this...In most practical quantum mechanical systems,quantum noise due to decoherence is highly biased towards dephasing.The quantum state suffers from phase flip noise much more seriously than from the bit flip noise.In this work,we construct new families of asymmetric quantum concatenated codes(AQCCs)to deal with such biased quantum noise.Our construction is based on a novel concatenation scheme for constructing AQCCs with large asymmetries,in which classical tensor product codes and concatenated codes are utilized to correct phase flip noise and bit flip noise,respectively.We generalize the original concatenation scheme to a more general case for better correcting degenerate errors.Moreover,we focus on constructing nonbinary AQCCs that are highly degenerate.Compared to previous literatures,AQCCs constructed in this paper show much better parameter performance than existed ones.Furthermore,we design the specific encoding circuit of the AQCCs.It is shown that our codes can be encoded more efficiently than standard quantum codes.展开更多
A new architecture of space-time codes as a combination of orthogonal space-time block codes （OSTBC） and linear dispersion codes （LDC） is proposed in order to improve the bit error rate（BER） performance of OSTBC...A new architecture of space-time codes as a combination of orthogonal space-time block codes （OSTBC） and linear dispersion codes （LDC） is proposed in order to improve the bit error rate（BER） performance of OSTBC.The scheme proposed is named linear dispersion orthogonal space-time block codes （LDOSTBC）.In LDOSTBC scheme,firstly,the data is coded into LDC codewords.Then,the coded LDC substreams are coded into OSTBC codewords again.The decoding algorithm of LDOSTBC combines linear decoding of OSTBC and ML decoding or suboptimum detection algorithms of LDC.Compared with OSTBC scheme when the rate of LDC is MtR,the performance of LDOSTBC scheme can be improved without decreasing the data rate,where Mt is the number of transmit antennas and R is the spectral efficiency of the modulation constellation.If some rate penalty is allowed,when the rate of LDC is less than MtR the performance of LDOSTBC can be improved further.展开更多
A cross-layer design(CLD)scheme with combination of power allocation,adaptive modulation(AM)and automatic repeat request(ARQ)is presented for space-time coded MIMO system under imperfect feedback,and the corresponding...A cross-layer design(CLD)scheme with combination of power allocation,adaptive modulation(AM)and automatic repeat request(ARQ)is presented for space-time coded MIMO system under imperfect feedback,and the corresponding system performance is investigated in a Rayleigh fading channel.Based on imperfect feedback information,a suboptimal power allocation(PA)scheme is derived to maximize the average spectral efficiency(SE)of the system.The scheme is based on a so-called compressed SNR criterion,and has a closed-form expression for positive power allocation,thus being computationally efficient.Moreover,it can improve SE of the presented CLD.Besides,due to better approximation,it obtains the performance close to the existing optimal approach which requires numerical search.Simulation results show that the proposed CLD with PA can achieve higher SE than the conventional CLD with equal power allocation scheme,and has almost the same performance as CLD with optimal PA.However,it has lower calculation complexity.展开更多
This paper studies the decoding performance of low-density parity-check(LDPC)codes in a serial concatenation system with polar codes employing the successive cancellation(SC)decoding.It is known that the absolute inco...This paper studies the decoding performance of low-density parity-check(LDPC)codes in a serial concatenation system with polar codes employing the successive cancellation(SC)decoding.It is known that the absolute incorrect log-likelihood ratio(LLR)values from the SC decoding can be very large.This phenomenon dramatically deteriorates the error correcting performance of the outer LDPC codes.In this paper,the LLR values of polar codes are regulated by a log processing before being sent to the LDPC decoder.Simulation results show that the log processing is an efficient approach with a low optimization complexity compared with the existing procedures to improve the performance of the serial concatenation systems.展开更多
Though belief propagation bit-flip(BPBF)decoding improves the error correction performance of polar codes,it uses the exhaustive flips method to achieve the error correction performance of CA-SCL decoding,thus resulti...Though belief propagation bit-flip(BPBF)decoding improves the error correction performance of polar codes,it uses the exhaustive flips method to achieve the error correction performance of CA-SCL decoding,thus resulting in high decoding complexity and latency.To alleviate this issue,we incorporate the LDPC-CRC-Polar coding scheme with BPBF and propose an improved belief propagation decoder for LDPC-CRC-Polar codes with bit-freezing(LDPCCRC-Polar codes BPBFz).The proposed LDPCCRC-Polar codes BPBFz employs the LDPC code to ensure the reliability of the flipping set,i.e.,critical set(CS),and dynamically update it.The modified CS is further utilized for the identification of error-prone bits.The proposed LDPC-CRC-Polar codes BPBFz obtains remarkable error correction performance and is comparable to that of the CA-SCL(L=16)decoder under medium-to-high signal-to-noise ratio(SNR)regions.It gains up to 1.2dB and 0.9dB at a fixed BLER=10-4compared with BP and BPBF(CS-1),respectively.In addition,the proposed LDPC-CRC-Polar codes BPBFz has lower decoding latency compared with CA-SCL and BPBF,i.e.,it is 15 times faster than CA-SCL(L=16)at high SNR regions.展开更多
In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver,...In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments.展开更多
An efficient LDPC-coded multi-relay cooperation architecture is proposed based on virtual vertical Bell Labs layered space-time （V-BLAST） processing for uplink communication, where minimum-mean-square-error （MMSE）...An efficient LDPC-coded multi-relay cooperation architecture is proposed based on virtual vertical Bell Labs layered space-time （V-BLAST） processing for uplink communication, where minimum-mean-square-error （MMSE） and BP-based joint iterative decoding based on the introduced muhi-layer Tanner graph are effectively de- signed to detect and decode the corrupted received sequence at the destination. By introducing V-BLAST transmis- sion to the coded multi-relay cooperation, relays send their streams of symbols simultaneously, which increases the data rate and significantly reduces the transmission delay. The theoretical analysis and numerical results show that the new LDPC coded cooperation scheme outperforms the coded non-cooperation under the same code rate, and it also achieves a good trade-off among the performance, signal delay, and the encoding complexity associated with the number of relays. The performance gain can be credited to the proposed V-BLAST processing architecture and BP-based joint iterative decoding by the introduced multi-layer Tanner graph at a receiver-side.展开更多
RS码是一种纠突发错误能力很强的信道编码方式,T urbo码是一种巧妙的将卷积码和随机交织器结合在一起,同时采用软输出并通过不断迭代的方法译码来逼近最大似然编码的一种新的纠错能力很强的信道编码方式;本文分析了两种编码方式并研究...RS码是一种纠突发错误能力很强的信道编码方式,T urbo码是一种巧妙的将卷积码和随机交织器结合在一起,同时采用软输出并通过不断迭代的方法译码来逼近最大似然编码的一种新的纠错能力很强的信道编码方式;本文分析了两种编码方式并研究了将二者级联后RS T urbo的性能,给出了将其级联码在图像传输中的应用。展开更多
文摘To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder to improve its performance at short interleaving delay. The combination of Log MAP and SOVA avoids updating the matrices of the maximum path, and also makes a contribution to the requirement of short delay. The simulation results of several SCCCs show that the improved decoder can obtain satisfied performance with short frame interleaver and it is suitable to the high bit rate low delay communication systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61802175,61871120,61872184,and 62071240)the Fundamental Research Funds for the Central Universities,China(Grant No.NZ2020021)。
文摘In most practical quantum mechanical systems,quantum noise due to decoherence is highly biased towards dephasing.The quantum state suffers from phase flip noise much more seriously than from the bit flip noise.In this work,we construct new families of asymmetric quantum concatenated codes(AQCCs)to deal with such biased quantum noise.Our construction is based on a novel concatenation scheme for constructing AQCCs with large asymmetries,in which classical tensor product codes and concatenated codes are utilized to correct phase flip noise and bit flip noise,respectively.We generalize the original concatenation scheme to a more general case for better correcting degenerate errors.Moreover,we focus on constructing nonbinary AQCCs that are highly degenerate.Compared to previous literatures,AQCCs constructed in this paper show much better parameter performance than existed ones.Furthermore,we design the specific encoding circuit of the AQCCs.It is shown that our codes can be encoded more efficiently than standard quantum codes.
基金Sponsored by the "111" Project of China (B08038)Important National Science & Technology Specific Projects (2009ZX03003-003+2 种基金2009ZX03003-004) the NSFC-Guangdong (U0635003)Program for Changjiang Scholars and Innovative Research Team in University(IRT0852)
文摘A new architecture of space-time codes as a combination of orthogonal space-time block codes （OSTBC） and linear dispersion codes （LDC） is proposed in order to improve the bit error rate（BER） performance of OSTBC.The scheme proposed is named linear dispersion orthogonal space-time block codes （LDOSTBC）.In LDOSTBC scheme,firstly,the data is coded into LDC codewords.Then,the coded LDC substreams are coded into OSTBC codewords again.The decoding algorithm of LDOSTBC combines linear decoding of OSTBC and ML decoding or suboptimum detection algorithms of LDC.Compared with OSTBC scheme when the rate of LDC is MtR,the performance of LDOSTBC scheme can be improved without decreasing the data rate,where Mt is the number of transmit antennas and R is the spectral efficiency of the modulation constellation.If some rate penalty is allowed,when the rate of LDC is less than MtR the performance of LDOSTBC can be improved further.
基金Supported by the Foundation of Huaian Industrial Projects(HAG2013064)the Foundation of Huaiyin Institute of Technology(HGB1202)the Doctoral Fund of Ministry of Education of China(20093218120021)
文摘A cross-layer design(CLD)scheme with combination of power allocation,adaptive modulation(AM)and automatic repeat request(ARQ)is presented for space-time coded MIMO system under imperfect feedback,and the corresponding system performance is investigated in a Rayleigh fading channel.Based on imperfect feedback information,a suboptimal power allocation(PA)scheme is derived to maximize the average spectral efficiency(SE)of the system.The scheme is based on a so-called compressed SNR criterion,and has a closed-form expression for positive power allocation,thus being computationally efficient.Moreover,it can improve SE of the presented CLD.Besides,due to better approximation,it obtains the performance close to the existing optimal approach which requires numerical search.Simulation results show that the proposed CLD with PA can achieve higher SE than the conventional CLD with equal power allocation scheme,and has almost the same performance as CLD with optimal PA.However,it has lower calculation complexity.
基金supported in part by National Natural Science Foundation of China through grant 61501002in part by Natural Science Project of Ministry of Education of Anhui through grant KJ2015A102+1 种基金in part by Talents Recruitment Program of Anhui Universityin part by the Key Laboratory Project of the Key Laboratory of Intelligent Computing and Signal Processing of the Ministry of Education of China, Anhui University
文摘This paper studies the decoding performance of low-density parity-check(LDPC)codes in a serial concatenation system with polar codes employing the successive cancellation(SC)decoding.It is known that the absolute incorrect log-likelihood ratio(LLR)values from the SC decoding can be very large.This phenomenon dramatically deteriorates the error correcting performance of the outer LDPC codes.In this paper,the LLR values of polar codes are regulated by a log processing before being sent to the LDPC decoder.Simulation results show that the log processing is an efficient approach with a low optimization complexity compared with the existing procedures to improve the performance of the serial concatenation systems.
基金partially supported by the National Key Research and Development Project under Grant 2020YFB1806805。
文摘Though belief propagation bit-flip(BPBF)decoding improves the error correction performance of polar codes,it uses the exhaustive flips method to achieve the error correction performance of CA-SCL decoding,thus resulting in high decoding complexity and latency.To alleviate this issue,we incorporate the LDPC-CRC-Polar coding scheme with BPBF and propose an improved belief propagation decoder for LDPC-CRC-Polar codes with bit-freezing(LDPCCRC-Polar codes BPBFz).The proposed LDPCCRC-Polar codes BPBFz employs the LDPC code to ensure the reliability of the flipping set,i.e.,critical set(CS),and dynamically update it.The modified CS is further utilized for the identification of error-prone bits.The proposed LDPC-CRC-Polar codes BPBFz obtains remarkable error correction performance and is comparable to that of the CA-SCL(L=16)decoder under medium-to-high signal-to-noise ratio(SNR)regions.It gains up to 1.2dB and 0.9dB at a fixed BLER=10-4compared with BP and BPBF(CS-1),respectively.In addition,the proposed LDPC-CRC-Polar codes BPBFz has lower decoding latency compared with CA-SCL and BPBF,i.e.,it is 15 times faster than CA-SCL(L=16)at high SNR regions.
文摘In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments.
基金Supported by the Science and Technology on Avionics Integration Laboratory and National Aeronautical Science Foundation of China(20105552)
文摘An efficient LDPC-coded multi-relay cooperation architecture is proposed based on virtual vertical Bell Labs layered space-time （V-BLAST） processing for uplink communication, where minimum-mean-square-error （MMSE） and BP-based joint iterative decoding based on the introduced muhi-layer Tanner graph are effectively de- signed to detect and decode the corrupted received sequence at the destination. By introducing V-BLAST transmis- sion to the coded multi-relay cooperation, relays send their streams of symbols simultaneously, which increases the data rate and significantly reduces the transmission delay. The theoretical analysis and numerical results show that the new LDPC coded cooperation scheme outperforms the coded non-cooperation under the same code rate, and it also achieves a good trade-off among the performance, signal delay, and the encoding complexity associated with the number of relays. The performance gain can be credited to the proposed V-BLAST processing architecture and BP-based joint iterative decoding by the introduced multi-layer Tanner graph at a receiver-side.
文摘RS码是一种纠突发错误能力很强的信道编码方式,T urbo码是一种巧妙的将卷积码和随机交织器结合在一起,同时采用软输出并通过不断迭代的方法译码来逼近最大似然编码的一种新的纠错能力很强的信道编码方式;本文分析了两种编码方式并研究了将二者级联后RS T urbo的性能,给出了将其级联码在图像传输中的应用。
