Algorithms for interference sensing in optical CDMA networks

Optical CDMA local area networks allow shared access to a broadcast medium. Every node is assigned an optical orthogonal codeword (OOC) to transmit or receive on. Optical CDMA systems have low throughput under moderate to heavy offered load due to interference between codewords. Interference sensing is a media access architecture where nodes on the network sense the amount of interference on the line before transmission. Nodes defer transmissions if there is interference on the line. This paper discusses and analyzes three algorithms for interference sensing. Through simulation it is shown that these algorithms reduce or eliminate throughput degradation at high loads. The study shows that simple algorithms such as selfish or threshold based algorithms are sufficient to eliminate throughput degradation.