The existing physical-layer network coding(PNC) can be grouped into three generic schemes,which are XOR-based PNC,superposition-based PNC,and denoising-and-forward(DNFbased) PNC.Generally speaking,DNF-based PNC has be...The existing physical-layer network coding(PNC) can be grouped into three generic schemes,which are XOR-based PNC,superposition-based PNC,and denoising-and-forward(DNFbased) PNC.Generally speaking,DNF-based PNC has better performance of rate pair region compared with the other two schemes when the transmission is symmetric.When the transmission is asymmetric,its performance is degraded severely.However,superposition-based PNC does not have that limitation even if its rate pair region performance is inferior to that of DNF-based PNC and XOR-based PNC.In this paper,we focus on the combined use of the two PNC schemes,superposition-based PNC and DNFbased PNC,and present a novel PNC scheme called joint superposition and DNF physical-layer network coding(JSDNF-based PNC) as well as the information theory analysis of the achievable rate pair region.At the same time,in the proposed scheme,an adaptive power allocation factor is introduced.By changing the power factor,the system can adapt its rate pair region flexibly.The numerical results show that the proposed scheme achieves the largest rate pair region when the rate difference of two source signals is very large.At the same time,the support on asymmetric transmission is also an important profit of the scheme.展开更多
As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,...As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.展开更多
Within the framework of the 5G new radio(NR),we propose a new hybrid automatic repeat request(HARQ)scheme to improve the throughput performance.The difference between the proposed scheme and the conventional one lies ...Within the framework of the 5G new radio(NR),we propose a new hybrid automatic repeat request(HARQ)scheme to improve the throughput performance.The difference between the proposed scheme and the conventional one lies in the first retransmission,where the erroneous coded block group is interleaved and superimposed(XORed)onto a fresh coded block group.At the receiver,an iterative message-passing decoding algorithm can be employed to recover the target erroneous code block group(CBG).Only when the superposed retransmission fails,the conventional incremental redundancy(IR)or repetition redundancy(RR)retransmission is initiated.In any case,since the first retransmission is along with but has negligible effect on the fresh CBG,it costs neither transmitted power nor bandwidth.Monte-Carlo simulation results reveal that the presented HARQ schemes can achieve throughput improvements up to 10%over block fading channels and up to 50%over fast fading channels in comparison with the original 5G CBG-level HARQ scheme but without excessively increasing the implementation 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
稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average...稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average Power Ratio,PAPR)特性。针对复用OFDM子载波SCMA系统具有高PAPR的特点,提出了一种低峰均比的SCMA多址方案,采用SC-FDMA技术,并进一步利用峰均比抑制技术对PAPR进行降低。理论和仿真结果表明,该算法能在PAPR性能、BER性能和系统复杂度间获得较好的权衡。展开更多
基金supported in part by National Natural Science Foundation of China under Grant No. 61071090Postgraduate Innovation Program of Scientific Research of Jiangsu Province under Grant No. CX10B -184Z
文摘The existing physical-layer network coding(PNC) can be grouped into three generic schemes,which are XOR-based PNC,superposition-based PNC,and denoising-and-forward(DNFbased) PNC.Generally speaking,DNF-based PNC has better performance of rate pair region compared with the other two schemes when the transmission is symmetric.When the transmission is asymmetric,its performance is degraded severely.However,superposition-based PNC does not have that limitation even if its rate pair region performance is inferior to that of DNF-based PNC and XOR-based PNC.In this paper,we focus on the combined use of the two PNC schemes,superposition-based PNC and DNFbased PNC,and present a novel PNC scheme called joint superposition and DNF physical-layer network coding(JSDNF-based PNC) as well as the information theory analysis of the achievable rate pair region.At the same time,in the proposed scheme,an adaptive power allocation factor is introduced.By changing the power factor,the system can adapt its rate pair region flexibly.The numerical results show that the proposed scheme achieves the largest rate pair region when the rate difference of two source signals is very large.At the same time,the support on asymmetric transmission is also an important profit of the scheme.
基金the National Key Research and Development Program of China(No.2017YFE0112600)the National Science Foundation of China[No.61971454,No.91438101&No.61771499]the National Science Foundation of Guangdong,China[No.2016A030308008].
文摘As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.
基金supported by the National Natural Science Foundation of China(No.61971454 and No.62071498)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011056)。
文摘Within the framework of the 5G new radio(NR),we propose a new hybrid automatic repeat request(HARQ)scheme to improve the throughput performance.The difference between the proposed scheme and the conventional one lies in the first retransmission,where the erroneous coded block group is interleaved and superimposed(XORed)onto a fresh coded block group.At the receiver,an iterative message-passing decoding algorithm can be employed to recover the target erroneous code block group(CBG).Only when the superposed retransmission fails,the conventional incremental redundancy(IR)or repetition redundancy(RR)retransmission is initiated.In any case,since the first retransmission is along with but has negligible effect on the fresh CBG,it costs neither transmitted power nor bandwidth.Monte-Carlo simulation results reveal that the presented HARQ schemes can achieve throughput improvements up to 10%over block fading channels and up to 50%over fast fading channels in comparison with the original 5G CBG-level HARQ scheme but without excessively increasing the implementation 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.
文摘稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average Power Ratio,PAPR)特性。针对复用OFDM子载波SCMA系统具有高PAPR的特点,提出了一种低峰均比的SCMA多址方案,采用SC-FDMA技术,并进一步利用峰均比抑制技术对PAPR进行降低。理论和仿真结果表明,该算法能在PAPR性能、BER性能和系统复杂度间获得较好的权衡。
