Rsearch On QoS Routing Of Wireless Mesh Networks

As a new network technology, Wireless Mesh Network (WMN) has gradually emerged inrecent years, and becomes an important part of the next generation Internet due to its obviousadvantages over other wireless networks. On the other hand, with the popularization of multimediabusiness and the development of commercial use, WMN is required to provide strong quality ofservice (QoS for short). Therefore, the research of QoS gurantee technology in WMN is importantboth in theory and practice. In this context, we emphasise on studying the key technologies ofproviding QoS gurantee for WMN in routing layer. The study includes unicast QoS routing schemeand multicast QoS routing scheme.QoS parameters, such as delay,bandwidth and packet loss rate are sensitive issues inmultimedia services. Therefore, the design of routing protocol should take into account a variety ofQoS requirements. This context proposes a muti-constrained QoS routing protocol (MQ-AODV) forunicast applications in WMN. By means of satisfying QoS requirements of different applications,the new protocol aims to solve the routing selection problem in WMN. In the process of routediscovery, MQ-AODV introduces"QoS dissatisfactory degree"to indicate the quality of a routing,in order to integrate multiple QoS constrains in a sole utility function, which make route selectionfor multi-metric simple. In the aspect of route maintenance, MQ-AODV protocol proposed apre-repair scheme to avoid the tramission delay caused by repairing route until link failure occurs.The simulation results show that,compared to the traditional AODV protocol, the MQ-AODVprotocol can better fulfill the delay and PER requirements of data flow, at the same time increasesnetwork throughput.For the multicast multimedia services, the context proposed a RAC-QoS (Rate-adaptiveAdmission Control-QoS) scheme to provide rate-adptive admission. RAC-QoS scheme estimatesnetwork bandwidth at the network layer and then give the feedback to the application layer, bydoing so the sending rate of the multicast source can be self-adapting. The RAC-QoS scheme canalso provides access control and Class of Service,and other function.The realization of RAC-QoSmechanism is mainly rely on the multicast routing protocol in routing layer. However, the sendingrate self-adapting in application layer indicates the idea of cross-layer design. The simulation resultsin different network scenarios show that, RAC-QoS mechanism can accurately response the network congestion, effectively reduce the transmission delay and packet loss, and to sum up,greatly improving network performance.