Mesh Distributed Coordination Function for Effecient Wireless Mesh Networks Supporting QoS

Wireless Mesh Networks (WMN) are receiving growing attention. They can widely find applications in Wireless Local Area Networks (WLAN), Wireless Metropolitan Area Networks (WMAN), Wireless Personal Area Networks (WPAN) and Wireless Sensor Networks (WSN), helping to substantially improve the network performance, cut down the operation cost and bring more convenience to both operators and end users. There are lots of open research issues in the field. Among them, the design of the Media Access Control (MAC) protocol is the most challenging one. This thesis proposes Mesh Distributed Coordination Function (MDCF), a novel MAC protocol that can be used to construct efficient WMNs supporting Quality of Service (QoS). MDCF applies Time Division Multiple Access (TDMA) to share the radio medium
in a fully distributed manner. It is able to run on a single frequency channel independent of physical schemes. Transmissions in MDCF networks take place in periodic time slots in a dynamic Time Division Duplex (TDD) mode of operation. A novel synchronization algorithm, operating under fully distributed control, is proposed for synchronizing mesh points (MP) for TDMA operation in the multi-hop environment. MDCF is well designed to properly handle highly loaded situations, hidden stations, exposed stations and capture effect which usually appear in a mesh environment and may dramatically deteriorate the network performance. For QoS support, besides a prioritized, collision eliminating and fair channel access mechanism, a distributed Radio Resource Control (RRC) protocol is used to evaluate and allocate a fair portion of
bandwidth to a specific traffic flow. The assigned portion of the bandwidth for a flow is adaptable with the traffic load and overall channel utilization. As a result, MDCF is able to efficiently exploit channel capacity, fairly distribute bandwidth and support multi-hop relaying of a large number of concurrent various traffic services in a WMN.