# A New Hybrid Prime Code for OCDMA Network Multimedia Applications
## 2 Literature Review
The maximum cross-correlation between any pair of code words is one. The authors evaluated the system performance in terms of the throughput based on a new method called effective normalized throughput with the diverse code method used as a benchmark. Moreover, the numerical simulations of the BER performance are presented. In [42], the authors constructed a high parameter-flexible 2D minimum weight OOC. They used minimum wavelengths that corresponded to the code weight with short lengths. Moreover, the electrical coding/decoding process was investigated based on the parallel interference cancellation receiver. The authors proved that when the encoder and decoder were implemented, electrically, the parallel interference cancellation receiver worked better than the conventional correlation receiver. In [43], a 2D spectral/spatial code was developed based on the existing modified quadratic congruence code and M-sequence code. The authors used a tunable fiber Bragg grating to construct the corresponding transceiver. The receiver was designed to eliminate the MAI and enhance the system BER performance. In [44], a new spectral/spatial code called diluted perfect difference code was developed. The code construction was based on the dilution method and the 1D perfect difference code. The corresponding OCDMA transceiver was presented. This code has a MAI cancellation property used to eliminate the interference between users due to multiple access. The authors proved that the BER performance, when calculated using the proposed code, is better than the other codes at 1.5 Gbps and 2.5 Gbps. In [45; 46], a new 2D wavelength/time code family was proposed based on the modified quadratic congruence code. The encoder/decoder structures were presented based on tunable optical delay lines. The balanced detector was used at the receiver to completely eliminate the MAI. It was proven that the OCDMA system using this new code can accommodate a larger number of active users with a better BER performance than the system using 2D wavelength/spatial M-matrix code. In [22], a 2D weighted modified prime code (WMPC) based on the existing MPC was developed. The author analyzed and presented the auto-correlation and cross-correlation properties of this new code in comparison with all the codes belonging to the MPC. The obtained results proved that the cross-correlation property of this code is limited to one and the auto-correlation property is higher than that of other MPC families. In [47], the design of 2D photonic crystal OCDMA encoder based on the WMPC was developed and presented. In [48; 49], a 2D multi-length WMPC (ML-WMPC), in multi-rate form based on multiple prime numbers, was used to accommodate different rates of multimedia services in the incoherent PPM-OCDMA network. In this research, the system BER performance was analyzed for different OCDMA receivers and the MAI cancellation receiver with Manchester encoding achieved better performance. The authors proved that the BER performance of network based on this multi-length code outperforms the ML-OOC's and all MPC families in the presence of the MAI cancellation receiver and Manchester encoding. In [50; 51], a new 2D double-length MPC (DL-MPC) was applied to wireless incoherent PPM-OCDMA and coherent BPSK-OCDMA networks, respectively. The wireless channel model was represented by a gamma-gamma model. In [51], the balanced detector was used at the receiving end to completely eliminate the MAI and other noise. The authors proved that the BER performance of coherent BPSK-OCDMA systems based on a new code outperforms all the incoherent and coherent systems using the other codes. In [52; 53], a 2D optimized MPC (OMPC) was developed to improve the BER performance of the PPM-OCDMA system by increasing the code weight of the DL-MPC to an optimum value. The MAI cancellation receiver was used to improve the signal-to-noise ratio. The code characteristics are compared with the other existing code characteristics and the proposed OMPC proved to be the best.