Performances Analysis of Novel Proposed Code for SAC-OCDMA System

摘要

The development of SAC-OCDMA system is based on the creation of new code structure. A novel proposed code structure is called ZFD that is based on the combination of various matrix creation methods and especially on the factorial function. This approach has not been exploited before in the OCDMA system. This novel code has its own advantage that represented in its possibility to generate code-words in flexible way by setting variable basic codes at fixed code weight. The performance of this proposed code is demonstrated via mathematical methods. It is represented by its optimal cross-correlation to avoid the multiple access interference (MAI). Consequently, the effects of the contributed noises using direct detection method have been considered. These noises are represented by shot noise and thermal noise. In addition, a system of three users was simulated with ZFD code under the C band (1530–1565 nm) for the upstream signal with different channel spacing (0.8, 1 and 1.2 nm). In this paper, several parameter effects such as fiber length, effective source power and data rate have been studied and compared to prove the effectiveness of this code. Also, ZFD code has been compared to some other codes such as RD, EDW and MDW according to the previous parameters. The suggested code has reached good results in terms of the bit error rate (BER) and the eye diagram.