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基带双极性光码分多址(OCDMA)系统,采用码的极性转换思想,实现在考虑信道非理想下的单极性信道中传输双极性码。研究了Gold序列,m序列在系统中的应用和传输信道对光码分多址系统性能的影响,仿真得到了双极性码在光码分多址系统的自相关和互相关特性,基于不同码字的光码分多址系统用户数与误码率的关系和基于非理想传输信道的系统性能影响曲线。结果表明,Gold序列和m序列适合双极性光码分多址系统,但Gold序列较m序列更适合应用到双极性光码分多址系统,当系统激活用户数为20,系统误码率分别达到了10-9,10-7,非理想传输信道对系统性能有较大的影响(恶化近20dB),在系统研究中不可忽略。
Baseband bipolar optical code division multiple access (OCDMA) system, using code polarity conversion idea, to achieve unipolar channel under the non-ideal channel transmission bipolar code. The application of Gold sequence and m sequence in the system and the influence of transmission channel on the performance of optical code division multiple access system are studied. The autocorrelation and cross-correlation of bipolar code in optical code division multiple access system are simulated. The relationship between the number of code division multiple access system users and bit error rate and the system performance impact curve based on non-ideal transmission channel. The results show that the Gold sequence and the m sequence are suitable for bipolar optical code division multiple access system. However, the Gold sequence is more suitable for the bipolar optical code division multiple access system than the m sequence. When the system activates the number of users is 20, Rate respectively reached 10-9,10-7, non-ideal transmission channel has a greater impact on system performance (deterioration of nearly 20dB), in system research can not be ignored.