Performance Analysis of a Spectrally Phase-Encoded Optical Code Division Multiple Access Packet Network

We analyze the performance of a spectrally phase-encoded optical code division multiple access slotted packet network based on a simple protocol. The steady-state throughput and average packet delay are derived as two measures to assess the performance of the network. First, only multiple access interference is considered and other sources of noise are neglected. In this context, comparing different systems with the fixed bit rate and chip duration leads us to conclude that increasing the code length improves the performance of networks with small average activity; but in highly active networks, decreasing the code length results in a significant improvement in the throughput and average packet delay. Next, Gaussian approximation is used in our performance analysis to consider both shot noise and thermal noise as well as multiple access interference. The packet success probability is derived as a function of transmitted power. It is shown that in a fixed bandwidth and with a fixed bit rate, increasing the code length can lead to better performance in high average powers. But, in the low-power regime, decreasing code length leads to better performance due to the lower level of activity.