摘要
针对高速光通信系统中高斯白噪声和偏振模色散(PMD)引起的干扰问题,研究了一种改进的前向纠错方法,通过向低密度奇偶校验(LDPC)码中插入具有固定信息的比特位("水印位")来估计信道,并将其与译码算法结合构成新的算法。研究发现,若以误比特率(BER)低于10-9为标准,则在纠错性能方面,高斯信道中含16、32位水印位的LDPC码与卡方信道中传统的LDPC码相比,所需的光信噪比(OSNR)值可分别减少约0.25dB、0.35dB;当考虑高速光通信中的PMD时,在差分群时延(DGD)为20ps和30ps时,含16、32位水印位的LDPC码与传统LDPC码字相比,所需OSNR值可分别减少约0.63dB、0.98dB和1.16dB、1.87dB。
To reduce the interference caused by channel noise and polarization mode dispersion （PMD） in the optical communication, a modified forward error correction method is studied. By inserting fixed bits which are defined as the watermark bits （water-bit） into the low density parity check （LDPC） codes to estimate the channel, a new decoding algorithm which is combined with channel estimation is proposed. The results show that the LDPC code with 16, 32 water- bit transmitted over Gaussian channel outperforms the conventional LDPC code transmitted over Chi-square channel in the error correction performance, and with bit error rate （BER） below 10^-9 as standard, the optical signal to noise ratio （OSNR） value can reduce about 0.25 dB, 0.35 dB. When PMD is considered in the high-speed optical communications, the LDPC code with 16, 32 water-bit has a better tolerance than the conventional LDPC code, when differential group delay （DGD） is 20 ps and 30 ps, the OSNR value can reduce about 0.63 dB, 0.98 dB and 1.16 dB, 1.87 dB.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2014年第6期141-147,共7页
Chinese Journal of Lasers
基金
国家自然科学基金(61205065)
国家863项目(2013AA013401)
山东省自然基金项目(ZR2010FM043)
区域光纤通信网与新型光通信系统国家重点实验室(上海交大)开放基金(2013GZKF031310)
关键词
光通信
信道估计
低密度奇偶校验码
前向纠错
偏振模色散
optical communications
channel estimation
low density parity check codes
forward error correction
polarization mode dispersion
