用于可见光通信的LDPC码策略  

LDPC dimming strategy for visible light communication

作　　者：朱庆[1] 吴乐南[1] 

机构地区：[1]东南大学信息科学与工程学院,南京210096

出　　处：《东南大学学报（自然科学版）》2014年第3期472-476,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(61271204)

摘　　要：为了改善可见光通信的信道译码性能、提高信息传输效率,利用PEG算法构造了一种LDPC纠错码方案.该方案充分利用了LDPC码码重分布高度集中在半码长附近并呈对称分布的性质,对码重处于中心区域附近的码字用增加定长补偿位的方式进行调光补偿,对码重处于远离中心区域的码字则先补位使之更加远离中心区域后再增加发送其补序列.在采用开关键控调制方式时,所提方案能够在统计意义上满足调光率的要求,解决了闪烁的问题.仿真结果表明,在中等码长时,与相同码长的修正一阶RM码相比,LDPC纠错码方案在码率方面提高了25倍以上,同时误码率性能也提高了约2 dB.To improve the decoding performance and increase the rate of the channel coding applied in visible light communications （VLC）,a low density parity check （LDPC）coding strategy con-structed by the progressive edge growth （PEG）algorithm is proposed.The characteristic of the dis-tribution of LDPC codes,the LDPC code-words symmetrically locating at the center of the code length,is utilized by the proposed LDPC coding strategy.Based on the distance apart from the cen-ter zone of the code-words distribution,all code-words are divided into two categories,the center code-words and the non-center code-words.For the former,a compensation sequence with fixed length is followed by the original code-word for the purpose of dimming compensation;for the lat-ter,a polarized sequence with the same fixed length is sent after the code-word and the complemen-tary sequence is sent for dimming compensation.The proposed scheme can meet the requirements of the dimming rate in a statistical sense,and solve the flicker problem of the on-off keying （OOK） modulation.The simulation results show that,in the medium code length,the proposed coding strat-egy increases the code rate more than 25 times and improves the bit error rate （BER）performance about 2 dB compared to the modified first-order Reed-Muller （RM）codes with the same code length.

关 键 词：OOK调制 低密度校验码 调光率 PEG算法 一阶RM码 可见光通信 

分 类 号：TN929.12[电子电信—通信与信息系统]