WDM multiple access protocol using node grouping scheme for passive double star networks

A WDM multiple access protocol for optical passive double star networks is proposed. It is presumed in the proposed protocol that all the nodes in the network are clustered to form multiple groups using passive star sub-hubs, and that the groups are connected together via a central passive star hub. A WDM channel is particularly allocated to each group as its home channel for data and control packet reception. Packets are transmitted over the pre-assigned TDM slots. Each node is equipped with a wavelength-tunable transmitter and a wavelength-fixed receiver tuned at the home channel of the group to which it belongs. An arbitration algorithm is also included to resolve data channel collision. It is shown in the performance evaluations that the proposed protocol has the advantages of the higher wavelength channel utilisation and less sensitivity to propagation delay time compared with the other protocols previously reported