在OCDMA系统中，系统地址码的相关值是直接影响码字性能的关键参数。对地址码相关值分布的研究是一项重要的工作。通过严密的代数运算以及统计分析，对Kwong所提出的PC相关值分布公式进行了一项小的修正。通过同样的方法，并根据逐步分析和简单的数据预测，得到了新的关于EQC的相关值分布公式。基于该EQC相关值分布公式，计算并比较了不同码字组合情况下所对应的误码率，最后得出采用EQC非零码字可以有效提高码字性能。

In OCDMA systems,the cross correlation of address codes is a crucial parameter which can directly affect the performance of the codes. Research of the distribution of the correlation becomes important work. Using strict algebraic operation and statistical analysis,a tiny modification on Kwong's distribution formula of PC is proposed. According to the same methods and means,a new distribution formula of EQC is also proposed. Based on this new distribution formula,the error probabilities corresponding to different combination of codes are compared. Finally it is concluded that using the address codes of EQC without user 0 can improve the performance effectively.