A simple analytical throughput–delay model for clustered FiWi networks

A fiber-wireless (FiWi) network integrates a passive optical network (PON) with wireless mesh networks (WMNs) to provide high-speed backhaul via the PON while offering the flexibility and mobility of a WMN. Generally, increasing the size of a WMN leads to higher wireless interference and longer packet delays. We examine the partitioning of a large WMN into several smaller WMN clusters, whereby each cluster is served by an optical network unit (ONU) of the PON. Existing WMN throughput–delay analysis techniques considering the mean load of the nodes at a given hop distance from a gateway (ONU) are unsuitable for the heterogeneous nodal traffic loads arising from clustering. We introduce a simple analytical queuing model that considers the individual node loads to accurately characterize the throughput–delay performance of a clustered FiWi network. We verify the accuracy of the model through extensive simulations. We employ the model to examine the impact of the number of clusters on the network throughput–delay performance. We find that with sufficient PON bandwidth, clustering substantially improves the FiWi network throughput–delay performance.