一种改进的TPC混合译码算法

为简化Turbo乘积码(Turbo Product Code,TPC)译码处理过程,缩短接收机译码时延,针对航天测控领域应用广泛的子码为扩展汉明码的TPC码,提出一种改进的混合译码算法。改进算法以传统混合译码算法为基础,把SISO和HIHO两种译码器相结合,优化软输入输出(Soft In Soft Out,SISO)中的外信息计算方式,纠正硬输入输出(Hard In Hard Out,HIHO)中的特殊错误图样,并引入切换门限完成SISO到HIHO的自适应切换,实现了基于码字可靠性的智能译码。仿真表明,对于TPC码(64,57)2,误码率为10-5时,改进算法在不减弱译码性能的前提下,复杂度仅为原算法的1/2。改进算法的提出及应用,将有利于航天测控设备小型化和国产化。

An Improved Hybrid Decoding Algorithm for Turbo Product Codes

An improved hybrid decoding algorithm is proposed to simplify the TPC decoding process and shorten decoding delay of the receiver for extended hamming code,widely used in aerospace track telemetry and control field.Based on the traditional hybrid decoding algorithm,the improved algorithm combines both SISO and HIHO decoder.The calculation of the extrinsic information in SISO algorithm is optimized and the special error patterns in HIHO algorithm can be corrected.An adaptive switching from SISO to HIHO by introducing the switching threshold is implemented based on the reliability of the TPC words.Simulation shows when bit error rate is 10-5,the complexity of the improved algorithm is about half of the original hybrid algorithm for TPC(64,57)2,without weakening decoding performance.It will be helpful for miniaturization and localization of aerospace TT&C equipment that the improved algorithm is put forward and applied.