Fig. 1: (Left) Architecture of a WOBAN. (Right) A WOBAN with multuple gateways.
The purpose of this research is to explore new methods for improving the quality of communications in wireless optical broadband access networks (WOBAN). Access networks are the last mile of the communication networks that connects the telecom central office (CO) to the residential or business users. Optical (such as passive optical networks) and wireless networks (such as wireless mesh networks) are initially deployed as the access networks. Optical networks are mainly used for high-bandwidth and long distance communications, whereas wireless tech- nologies are used for exibility and low bandwidth uses. The present growing demands for bandwidth-intensive services and at the same time the exibility (anytime-anywhere service) of the users are accelerating the research on effcient and cost-effective access infrastructures where optical-wireless combinations are seen as a promising approach. WOBAN is a novel hybrid access network paradigm with the combination of high-capacity optical backhaul and highly exible wireless front-end that can provide higher bandwidth in a cost effective manner. In WOBAN architecture, optical fibers are provided as far as possible from the CO to the end users and then wireless access is provided in the front end (shown in Fig. 1). Because of it's excellent compromise, this WOBAN architecture enjoys lesser deployment costs because of lesser fiber costs than traditional passive optical networks.
A WOBAN consists of a passive optical networks (PON) at the back end and a multi-hop wireless mesh networks at the front end. At the back end, optical line terminal (OLT) resides in the CO and feed to multiple optical network units (ONUs) through a traditional fiber network. At the front end, wireless mesh routers form a multi-hop wireless mesh network; and a few of the mesh routers are called gateways that are attached to the ONUs. Thus if a mesh router needs to send a packet to the Internet, it has to send it to any one of the gateways and after that the packet is sent through the optical part of the WOBAN. In the upstream direction (from wireless routers to gateways), WOBAN is an anycast network. In the downstream (from gateway to mesh router), a gateway send a packet to a speciffic wireless router, thus in downstream, WOBAN is a unicast network. Our interest in this project is to develop adaptive routing protocols in the upstream direction. We have also explored the advantages of multiple channels and multiple radios, by designing a joint routing and channel assignment (JRCA) scheme in a multi-gateway WOBAN architecture. Extensive simulation results demonstrate potential benefits for ensuring route quality and reducing interference in multi-channel WOBAN.
Related Publications: