在保证误码率较低的前提下, 为了获得较大的码容量, 现以扩展二次素数码作为扩时序列, 以二次全等跳频码作为跳频序列, 构造出了一种新的二维光正交码ESPC/QCHC。分析了ESPC/QCHC的码字性能, 得到了该码字的平均互相关表达式。对该码字的码字容量进行理论分析, 并对其误码率进行了MATLAB仿真。结果表明, 当码重(或码长)一定时, 增加频率片数会降低误码率; 同其他几种以素数码作为扩时序列构造出的二维光正交码相比, 该码字有较低的误码率, 较大的码容量。最后在Optisystem7.0中对ESPC/QCHC在光码分多址系统中的误码率进行仿真分析, 验证了其有较好的误码性能。

Under the premise of low Bit Error Rate (BER), in order to obtain larger code capacity, a new two-dimensional Optical Orthogonal Code (OOC) named ESPC/QCHC is constructed with Extend Square Prime Code (ESPC) as time spreading sequence and Quadratic Congruence-Hop Code (QCHC) as wavelength hopping sequence. The cross-correlation mean value is deduced by analyzing the performance of ESPC/QCHC. The word capacity of the code is theoretically analyzed, and the BER of the code is simulated by MATLAB. The results show that lower BER can be achieved by increasing the number of frequencies when the same code weight (or code length) is given. This code has lower BER and larger code capacity when compared with other two dimensional OOC which constructed by the prime number as time spreading sequence. The simulation results in the Optical Code Division Multiple Access (OCDMA) system have shown that the BER performance ESPC/QCHC is better.