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
LDPC(Low Density Parity Check)码是无线通信系统中高效的信道编码技术,并已经在第五代移动通信等系统中应用,码率兼容则是在应用中遇到的重要问题之一。码率兼容的关键在于在不增加译码复杂度的情况下,实现低码率到高码率的任意变化...LDPC(Low Density Parity Check)码是无线通信系统中高效的信道编码技术,并已经在第五代移动通信等系统中应用,码率兼容则是在应用中遇到的重要问题之一。码率兼容的关键在于在不增加译码复杂度的情况下,实现低码率到高码率的任意变化。论文提出了一种码率兼容多元LDPC码的比特级打孔算法。该算法首先将多元符号矩阵转换为二元比特矩阵,其次利用最小环路检测算法检测每个比特变量节点所在环路大小,并选择大环路比特变量节点进行打孔。仿真结果表明,针对码长256、码率0.5的非规则四元LDPC码及码长155、码率0.4得规则LDPC码,论文所提算法均大约有0.1dB~0.25 dB的增益。展开更多
为了提高低密度校验（low density parity check,LDPC）码的打孔性能,提出一种基于校验矩阵优化扩展的码率兼容LDPC码设计方法.从码率兼容码的度分布约束关系出发,提出母码的度分布优化算法.在此基础上,结合打孔变量点的译码恢复规则,...为了提高低密度校验（low density parity check,LDPC）码的打孔性能,提出一种基于校验矩阵优化扩展的码率兼容LDPC码设计方法.从码率兼容码的度分布约束关系出发,提出母码的度分布优化算法.在此基础上,结合打孔变量点的译码恢复规则,构造适合打孔的LDPC码校验矩阵.采用贪婪搜索算法逐级最大化不同类型的打孔变量点数目,提高码率兼容系列子码的误码性能.仿真结果表明,与编码高效的码率兼容LDPC码相比,所提方法生成的码率兼容子码误码性能有较大改善,特别是当码率大于0.8时,编码增益提高约0.7～0.8 dB.展开更多
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.
文摘LDPC(Low Density Parity Check)码是无线通信系统中高效的信道编码技术,并已经在第五代移动通信等系统中应用,码率兼容则是在应用中遇到的重要问题之一。码率兼容的关键在于在不增加译码复杂度的情况下,实现低码率到高码率的任意变化。论文提出了一种码率兼容多元LDPC码的比特级打孔算法。该算法首先将多元符号矩阵转换为二元比特矩阵,其次利用最小环路检测算法检测每个比特变量节点所在环路大小,并选择大环路比特变量节点进行打孔。仿真结果表明,针对码长256、码率0.5的非规则四元LDPC码及码长155、码率0.4得规则LDPC码,论文所提算法均大约有0.1dB~0.25 dB的增益。
文摘为了提高低密度校验（low density parity check,LDPC）码的打孔性能,提出一种基于校验矩阵优化扩展的码率兼容LDPC码设计方法.从码率兼容码的度分布约束关系出发,提出母码的度分布优化算法.在此基础上,结合打孔变量点的译码恢复规则,构造适合打孔的LDPC码校验矩阵.采用贪婪搜索算法逐级最大化不同类型的打孔变量点数目,提高码率兼容系列子码的误码性能.仿真结果表明,与编码高效的码率兼容LDPC码相比,所提方法生成的码率兼容子码误码性能有较大改善,特别是当码率大于0.8时,编码增益提高约0.7～0.8 dB.
