高码率无线光通信交织卷积编码新方案研究  

Study on new scheme of byte-wise interleaving and convolutional coding for high-data-rate optical wireless communication system

作　　者：宋效正[1] 刘璐[1] 党安红[1] 汤俊雄[1] 

机构地区：[1]北京大学信息科学技术学院量子所,北京100871

出　　处：《通信学报》2007年第10期38-43,47,共7页Journal on Communications

基　　金：国家自然科学基金资助项目(60240420237;60572002)~~

摘　　要：为了克服大气湍流引起的光信号的深衰落,提高交织器的交织深度是一种有效的方法。提出了一种新的前向纠错方案用来降低交织深度较大的交织器设计的复杂性,该方案在发射端采用交错卷积编码结构,将编码输出序列经字节组合后,再通过字节交织方式离散大气湍流所引起的衰落信号;在接收端设计成字寻址的解交织,给出了一种对数度量量化的软判决Viterbi并行译码方式。针对该方案进一步优化了字节组合方式,提出了与之相匹配的新型的互质型分段字节卷积交织结构。将该方案用于通信速率为300Mbit/s的无线光通信系统,仿真结果表明,该方案能够降低交织器和单译码器的处理速度要求,而且在误码率为10?6时,相对于最佳阈值判决有约6.9dB的编码增益,与完美交织下的编码性能仅相差0.3dB,这在高码率无线光通信系统中抑制大气湍流的影响有潜在的应用价值。Increasing interleaving depth can mitigate the impact of long deep fade induced by atmospheric turbulence. A new scheme of a FEC coding with large-depth interleaving was proposed. The transmitter was designed using an m-stage interlaced convolutional coding in combination with byte-wise interleaving; correspondingly the receiver performed word-wise deinterleaving and parallel soft-decision Viterbi decoding based on logarithmic quantization of channel input. Furthermore, a rule of byte combination was analyzed and a new configuration of co-prime byte-wise convolutional in- terleaving was presented. The results show that the new scheme reduces the complexity and the speed requirement of system design. Compared with the optimum threshold detection at a BER of 10-6, coding gains of 6.9dB were achievable by the new scheme at source data rates of 300Mbit/s. The loss with respect to perfect interleaving is only 0.3 dB. Hence, the new scheme is superior in high-data-rate optical wireless communication system.

关 键 词：无线光通信 卷积交织 Viterbi并行译码 

分 类 号：TN929.12[电子电信—通信与信息系统]