THE RECEIVER COLLISION-AVOIDANCE (RCA) PROTOCOL FOR A SINGLE-HOP WDM LIGHTWAVE NETWORK

We propose a multiple access protocol for a single-hop wavelength divi sion multiplexing (WDM)-based multichannel local lightwave network. Th e protocol can support a large number of high-speed bursty traffic nod es interconnected via a passive optical star coupler. Each node is equ ipped with only one transmitter and one receiver, both of which are tu nable over all the channels. A single control channel is established t o arbitrate access to the other channels, called data channels. Access to the control channel is provided via a variation of slotted ALOHA s o that the system is scalable. Unlike other protocols proposed in [11] , [18], [23], our protocol contains a simple mechanism which can dynam ically detect and avoid receiver collisions (hence it is called the re ceiver collision avoidance (RCA) protocol). In addition, nonzero chann el propagation delay and nonzero transceiver tuning times are taken in to account and the system can be readily implemented with current ligh twave technology. The protocol allows overlapping of one node's tuning time with the nodes' packet transmission time to reduce the performan ce penalty of large tuning time. We analyze the performance of the RCA protocol by first constructing a finite population Markov chain. Then , the equilibrium point analysis (EPA) technique is adopted to obtain the average data packet delay and system throughput. Numerical results show that the maximum throughput is around 36% of the total data chan nel capacity and degrades slightly for larger transceiver tuning times . Also, for a typical network with round-trip propagation delay being ten times the data packet transmission time, about 20 data channels ar e needed to support 500 nodes without overloading the system.