第3代GPS民用信号L1C的CNAV-2电文采用了LDPC编码以提高电文解调性能。由于传统接收机常用的硬判决译码不能充分利用信道信息,探讨了译码性能更优的软判决译码方法。首先仿真分析了适合L1C接收机的软判决译码算法及其性能和复杂度,表明...第3代GPS民用信号L1C的CNAV-2电文采用了LDPC编码以提高电文解调性能。由于传统接收机常用的硬判决译码不能充分利用信道信息,探讨了译码性能更优的软判决译码方法。首先仿真分析了适合L1C接收机的软判决译码算法及其性能和复杂度,表明软判决译码能够提供比硬判决高2~3 d B的编码增益。然后设计了完整的CNAV-2电文译码方案,包括帧同步、LDPC和BCH译码、解交织、CRC校验和相干合并策略及流程,并在软件接收机上得以实现。最后通过实际QZSS卫星信号和商用射频GNSS模拟器信号验证了设计的正确性。展开更多
A novel adaptively iterative list decoding(ILD) approach using for Reed-Solomon(RS) codes was investigated. The proposed scheme is exploited to reduce the complexity of RS Chase algorithm(CA) via an iterative decoding...A novel adaptively iterative list decoding(ILD) approach using for Reed-Solomon(RS) codes was investigated. The proposed scheme is exploited to reduce the complexity of RS Chase algorithm(CA) via an iterative decoding attempt mode. In each decoding attempt process, a test pattern is generated by flipping the bits of the least reliable positions(LRPs) within the received hard-decision(HD) vector. The ILD algorithm continues until a test pattern is successfully decoded by the underlying Berlekamp-Massey algorithm(BMA) of RS codes. Flipping within the same bits, the ILD algorithm provides the same test pattern set as the conventional RS CA, thus there is no degradation in error-rate performance. Without decoding all test patterns, the ILD algorithm can simplify the decoding complexity by its early termination. Simulation results show that the average complexity of the ILD algorithm is much lower than that of the conventional RS CA(and is similar to that of BMA decoding) at high signal-to-noise ratio(SNR) region with no less to the RS CA decoding error-rate performance.展开更多
首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5...首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5时,当仅提高最小汉明距离码率相同或者仅减小码率最小汉明距离相同时,BCJR算法相对于硬判决译码算法的编码增益分别在之前的编码增益基础上又增加了0.15dB和0.25dB。因此设计级联码方案时,应尽可能选择纠错能力较大的内码。此外也可以采用适当增加内码的冗余度相应减小外码的冗余度的方法,在获得更高的编码增益的同时保证整个系统的带宽利用率不变。展开更多
Soft-decision decoding of BCH code in the global navigation satellite system( GNSS) is investigated in order to improve the performance of traditional hard-decision decoding. Using the nice structural properties of BC...Soft-decision decoding of BCH code in the global navigation satellite system( GNSS) is investigated in order to improve the performance of traditional hard-decision decoding. Using the nice structural properties of BCH code,a soft-decision decoding scheme is proposed. It is theoretically shown that the proposed scheme exactly performs maximum-likelihood( ML) decoding,which means the decoding performance is optimal. Moreover,an efficient implementation method of the proposed scheme is designed based on Viterbi algorithm. Simulation results show that the performance of the proposed soft-decision ML decoding scheme is significantly improved compared with the traditional hard-decision decoding method at the expense of moderate complexity increase.展开更多
文摘第3代GPS民用信号L1C的CNAV-2电文采用了LDPC编码以提高电文解调性能。由于传统接收机常用的硬判决译码不能充分利用信道信息,探讨了译码性能更优的软判决译码方法。首先仿真分析了适合L1C接收机的软判决译码算法及其性能和复杂度,表明软判决译码能够提供比硬判决高2~3 d B的编码增益。然后设计了完整的CNAV-2电文译码方案,包括帧同步、LDPC和BCH译码、解交织、CRC校验和相干合并策略及流程,并在软件接收机上得以实现。最后通过实际QZSS卫星信号和商用射频GNSS模拟器信号验证了设计的正确性。
基金supported by the National Natural Science Foundation of China (61671080,61601047)
文摘A novel adaptively iterative list decoding(ILD) approach using for Reed-Solomon(RS) codes was investigated. The proposed scheme is exploited to reduce the complexity of RS Chase algorithm(CA) via an iterative decoding attempt mode. In each decoding attempt process, a test pattern is generated by flipping the bits of the least reliable positions(LRPs) within the received hard-decision(HD) vector. The ILD algorithm continues until a test pattern is successfully decoded by the underlying Berlekamp-Massey algorithm(BMA) of RS codes. Flipping within the same bits, the ILD algorithm provides the same test pattern set as the conventional RS CA, thus there is no degradation in error-rate performance. Without decoding all test patterns, the ILD algorithm can simplify the decoding complexity by its early termination. Simulation results show that the average complexity of the ILD algorithm is much lower than that of the conventional RS CA(and is similar to that of BMA decoding) at high signal-to-noise ratio(SNR) region with no less to the RS CA decoding error-rate performance.
文摘首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5时,当仅提高最小汉明距离码率相同或者仅减小码率最小汉明距离相同时,BCJR算法相对于硬判决译码算法的编码增益分别在之前的编码增益基础上又增加了0.15dB和0.25dB。因此设计级联码方案时,应尽可能选择纠错能力较大的内码。此外也可以采用适当增加内码的冗余度相应减小外码的冗余度的方法,在获得更高的编码增益的同时保证整个系统的带宽利用率不变。
基金Sponsored by the National Natural Science Foundation of China(Grant No.61271423)
文摘Soft-decision decoding of BCH code in the global navigation satellite system( GNSS) is investigated in order to improve the performance of traditional hard-decision decoding. Using the nice structural properties of BCH code,a soft-decision decoding scheme is proposed. It is theoretically shown that the proposed scheme exactly performs maximum-likelihood( ML) decoding,which means the decoding performance is optimal. Moreover,an efficient implementation method of the proposed scheme is designed based on Viterbi algorithm. Simulation results show that the performance of the proposed soft-decision ML decoding scheme is significantly improved compared with the traditional hard-decision decoding method at the expense of moderate complexity increase.
