Proposal of an optical CDMA random access protocol

Abstract

A new random access protocol for optical code division multiple access (CDMA) communication systems is proposed. Stop & wait automatic repeat request (ARQ) is implemented at the optical link layer. A detailed state diagram and a mathematical model based on the equilibrium point analysis (EPA) technique are presented. Several performance measures are evaluated under different network parameters. We also compare the performance of the proposed protocol to that of the round robin receiver/transmitter (R 3T) protocol which is based on a go back-n technique. Finally, the proposed protocol is analyzed when a queuing subsystem is added. We prove by numerical analysis that the proposed protocol is less complex and significantly outperforms the R 3T protocol. Our results also reveal that the performance of the proposed protocol with correlation receivers is competitive to that of the R 3T protocol with chip-level receivers, which reduces the overall system cost. We finally show that a slight improvement in the protocol's performance can be achieved by only adding a single buffer to the system. The blocking probability is also reduced and the queuing delays that added to the total network latency are still acceptable.