Design and analysis of a WDMA protocol for passive star-coupled lightwave networks

Based on the POPSMAC protocol proposed in Chung-Sheng Li et al. (1993), we propose an improved medium access protocol for wavelength division multiple access (WDMA) photonic networks. Using the same set of photonic devices as in POPSMAC, the proposed protocol alleviates the drawbacks of the POPSMAC protocol, e.g., invalid data transmissions following receiver collisions and possible acknowledgement packet collisions with header/data packets, while retaining many advantages of POPSMAC. As a result, the network performance in terms of the throughput and the packet delay is improved. Analytical models based on the timing diagram analysis, the continuous-time Markov chain, and the randomization technique are developed to assess the performance of the proposed protocol. The performance is evaluated in terms of channel utilization, mean packet delay, and packet delay distribution with variations in the number of nodes, the offered traffic, the size of data packets, and the network propagation delay. Numerical results show that the proposed protocol achieves better channel utilization and incurs lower packet delays than POPSMAC.