改进的平衡解码器在OCDMA中的性能分析

Performance analysis of modified balance decoder in the OCDMA system

构建了基于改进型平衡解码器光电检测输出电流均值和方差的概率统计分析模型,推导在频谱幅度光码分多址系统中的封闭误码率性能表达式.仿真结果表明:改进型平衡解码器无论采用固定或非固定互相关值序列都能消除多接入干扰,取消了传统双平衡解码器的恒定互相关值约束条件,推导的系统误码率性能介于上下边界之间,模拟结果与理论分析一致.同时以并发上线用户数、传输速率和码重为参数,仿真得到这些参数对系统误码率的影响,并根据应用场景调整它们使其满足系统性能需求.

With the modified balance decoder photo-detector′s output current mean and variance, probability and statistics analysis model was constructed in this paper,and closed-form BER （bit error rate）performance of SAC-OCDMA （spectral-amplitude-coding optical code-division multiple-access） system was derived.The simulation results show that the modified balance decoder can eliminate mul-tiple access interference with the code sequences whether fixed or not fixed cross correlation,then cancel the customary double balanced decoder fixed cross correlation values premise.The BER value is between the upper and lower boundaries of the system,and the simulation results are consistent with the theoretical analysis.The number of simultaneous users,transmission rate and code weight were taken as parameter to simulate their effect on the system BER,which can be adj usted to meet the re-quirements of application scenarios.