光码分多址系统中光学相关接收机判决阈值的分析

介绍了光码分多址系统中常用地址码（一维扩时码、二维码和三维码）的特点，并对它们各自的互相关均值和方差进行了理论分析。基于非相干光码分多址系统中光学相关接收机的基本原理，结合不同的用户地址码，对系统误码率性能进行了分析，得到了接收机最佳判决阈值与地址码基本特性参数和系统同时用户数间的关系。最后，给出了数值仿真结果。结果表明，对于采用特定地址码的光码分多址系统，只有选择合适的接收机判决阈值，系统的误码率性能才能达到最佳。研究结果对光码分多址系统中接收机判决阈值的选取具有一定的参考作用。

Analysis of decision threshold for optical correlation receivers in OCDMA system

Addressing codes frequently used in optical code-division multiple-address(OCDMA) systems are introduced.They are typically one dimensional time-spreading code,two-dimensional code and three dimensional code.The means and variances of cross-correlation for these codes were analyzed.Based on the fundamental principle of optical correlation receivers used in incoherent OCDMA systems,with different addressing codes taken into account, the bit error probability(BEP) of the system was studied.The dependence of optimum decision threshold on the basic parameters of addressing codes and the number of simultaneous users was obtained.Finally,numerical simulations are carried out,and the results show that system BEP performance is optimized when appropriate decision threshold is taken.