This paper introduces a family of error correcting codes called zigzag codes. A zigzag code is described by a highly structured zigzag graph. Due to the structural properties of the graph, very low complexity soft ...This paper introduces a family of error correcting codes called zigzag codes. A zigzag code is described by a highly structured zigzag graph. Due to the structural properties of the graph, very low complexity soft in, soft out decoding rules can be implemented. We present a decoding rule, based on the Max Log APP(MLA) formulation, which requires a total of only 20 addition equivalent operations per information bit per iteration. Simulation of a rate 1/2 concatenated zigzag code with four constituent encoders with interleaver length 65536 yields a bit error rate (BER) and of 10 5 at 0.9 dB and 1.4 dB away from the Shannon limit by optimal (APP) and low cost sub optimal (MLA) decoders, respectively.展开更多
文摘This paper introduces a family of error correcting codes called zigzag codes. A zigzag code is described by a highly structured zigzag graph. Due to the structural properties of the graph, very low complexity soft in, soft out decoding rules can be implemented. We present a decoding rule, based on the Max Log APP(MLA) formulation, which requires a total of only 20 addition equivalent operations per information bit per iteration. Simulation of a rate 1/2 concatenated zigzag code with four constituent encoders with interleaver length 65536 yields a bit error rate (BER) and of 10 5 at 0.9 dB and 1.4 dB away from the Shannon limit by optimal (APP) and low cost sub optimal (MLA) decoders, respectively.
文摘水声网络(underwater acoustic network,UAN)具有长传播时延、高误码率、半双工通信等特性,这些特性严重影响了UAN中数据的可靠传输。而在线喷泉码具有在线控制、编解码复杂度低、码率自适应等诸多优势,在线喷泉码适合于保障UAN中数据的可靠传输。针对递归与限制反馈的在线喷泉码(recursive OFC with limited feedback,ROFC-LF)存在不理想覆盖和4元环问题导致略高的开销和频繁的反馈,提出适用于UAN的基于优先级与可Zigzag解码的ROFC-LF(priority-based and zigzag-decodable ROFC-LF,P-ZROFC-LF)。P-ZROFC-LF在建立阶段选取具有最高优先级的原始包进行编码直至所有原始包均参与编码。同时,引入可Zigzag解码编码,将无用编码包进行移位异或转换为有用编码包来提高解码性能。通过随机图理论,分析P-ZROFC-LF所需编码包数与原始包数之间的关系。理论分析与仿真结果表明,与大部分在线喷泉码相比,P-ZROFC-LF显著提高了反馈和开销性能。其中P-ZROFC-LF相比于ROFC-LF的反馈和开销分别减少了18%和0.0176,更适用于UAN。
