采用隐序列估计无线光信道时直流偏置的消除

DC offset elimination in wireless optical channel estimation by employing implicit sequence

针对在无线光通信系统中采用隐序列信道估计时存在的直流偏置问题,提出了一种利用信道状态参数消除直流偏置的新的隐序列信道估计方法,并对影响系统性能的关键因素进行了研究。采用均衡后输出信噪比最大准则推导并获得了最优功率分配因子,并用仿真实验分析了该方法的均方误差、计算复杂度等性能参数以及应用该方法后系统的误码率等。仿真结果显示:采用该方法有效地减小了直流偏置对系统性能的影响,与传统隐序列信道估计方法相比,其均方误差减小了约1/2,且均衡后系统的误码性能得到了明显改善;在最佳功率分配条件下,当误码率为4×10^(-3)时,直流偏置分别为0.2和0.4对应系统的信噪比分别改善了约2dB和6dB,而计算复杂度仅增加了14.2%。

For the DC offsets caused by traditional implicit sequence based channel estimation in wireless optical communication links,a novel implicit sequence based channel estimation method was proposed to eliminate the DC offsets.Some key factors affecting the system performance were investigated.The maximum output Signal-to-Noise Ratio（SNR）criterion was used to derive the optimal power allocation factor.Then,a simulation experiment was performed to evaluate its mean square error,bit error rate and computational complexity.The results show that the proposed method effectively eliminates the influence of DC offset.on the system performance.Compared to the traditional method,the mean square error is reduced by about 1/2and the bit error rate is significantly improved.Under the optimal power distribution conditions,when the bit error rate is 4×10^-3,the SNRs of 0.2 and 0.4DC offset scenarios are improved by about 2dB and 6dB,respectively,while the computational complexity is only increased by 14.2%.