基于扩展的双曲同余码/素数码的二维光正交码

构造了一种扩展的双曲同余码(EHC)，用该码作为时间扩频伪随机序列和以素数码(PC)作为波长跳频伪随机序列，形成了一种新的二维光正交码EHC／PC．与EQC／PC相比，两者的码字数相同，互相关性能相当，但前者扩频系数和码重较小，可以提高用户的数据速率并降低对光编／解码器的要求．模拟计算表明，当同时使用的用户数较少时，EQC／PC的误码率比EHC／PC略低；当同时使用的用户数中等或较多时，两者的误码率性能相当．因此，EHC／PC比EQC／PC更适合于同时使用的用户数中等或较多的光码分多址(OCDMA)系统．

A New Two-Dimensional Optical Orthogonal Codes Based on Extended Hyperbolic Congruence Codes/Prime Codes

A new one-dimensional optical orthogonal codes(1D-OOC), named extended hyperbolic congruence codes (EHC), was first constructed, and its performance was analyzed. Using the EHC for time spreading and prime codes (PC) for wavelength hopping, a new two-dimensional optical orthogonal codes(2D-OOC) named EHC/PC was constructed. Then, the performance of EHC/PC was analyzed, and also compared with EQC/PC. It is shown that EHC/PC has the same code cardinality and comparable cross- correlation performance, but has shorter code length and smaller code weight which can enhance user data rate and also reduce the complexity of optical encoders/decoders. The simulation analysis shows that, EQC/PC performs a little better than EHC/PC when the traffic load is light, but both have comparable performance for medium or heavy traffic. Therefore, EHC/PC is more suitable for optical CDMA networks with medium or heavy traffic.