【摘要】 针对光码分多址(OCDMA)的多用户干扰问题,提出一种引入光硬限幅器、基于最大值判决的光码分多址并行干扰抑制系统·该系统在发送端对比特"0"和比特"1"分别使用一个地址码和它的移位变形进行映射,以避免发送比特"0"时无光脉冲通过的问题,实现并行干扰抑制;在接收端光电检测器前引入一个光硬限幅器,判决电路采用最大值判决,以避免门限判决所引起的误判,进一步减小多用户干扰·阐述了其工作原理,系统采用光正交码作为地址码,PIN光电检测器,分析推导了系统的误码率表达式,进而对新型系统的多用户干扰抑制作用进行误码性能仿真·仿真结果表明,当信号光子到达率为25时,新型系统比常规系统的误码性能改善10个数量级以上,比常规并行干扰抑制系统改善2个数量级以上·更多还原

【Abstract】 Aiming at multi-user interference that exists in optical code division multiple access(OCDMA) system,a novel parallel interference suppressing system is presented,which adopts an optical hard limiter and maximum value decision.It avoids no optical pulse existing while bit 0 is transmitted by adopting a spread spectrum code and its shift as the address codes of bit 0 and bit 1,respectively; placing an optical hard-limiter before correlator in receiver,and using maximum decision instead of threshold decision to decrease error-decision happening.The fundamental of the system is stated,optical orthogonal codes is applied as address codes;PIN opto-electro detector is used,the bit error probability of the novel system is derived and analyzed.Simulations based on the expression are done.The results show that the bit error performance of the novel system can be ten orders better than that of conventional system,two orders better than conventional parallel interference suppressing system while signal photon arrival rate is 25.更多还原