Cross-Layer Moder And QoS Routing For Wireless Multimedia Sensor Networks

In order to meet the increasing requirements of envirionment surveillance, we should introduce information-rich media such as video and audio into Wireless Sensor Networks.And this lead to the development of WMSN (Wireless Multimedia Sensor Networks). With the continuous deepening research and application, the needs of differentiated services with QoS (Quality of Service) assurance to support multimedia existing in WMSN are becoming more and more urgent. QoS guarantee has a direct influence on the overall performance and the practicability of WMSN.The sensor nodes in WMSN are limited in power and have low bandwidth. Besides, the topology of wireless networks change continually according to the death or mobility of nodes. Since these features, the existing researches of QoS supporting for tradition networks are not applicable to WMSN. Such characteristics and difficulties resulted in the proposal of some new technology and protocols.There are corresponding mechanisms for each layer of network protocol stacks to improve QoS performance, including MAC protocol, routing algorithms, dynamic self-adaptive strategy and so on. As the main technique of network layer to actualize QoS guarantee, QoS routing protocols are vital to the performance of WMSN.This paper mainly carries on research to QoS of WMSN. Firstly, the paper introduces studies on QoS of WMSN . Secondly, we analyze QoS assurence methods of WMSN , lay out two representative cross-layer models of QoS guarantee and give the differences between these models. Thirdly, on the basis of the existing routing protocols, a new cross-layer QoS routing protocol named CLQDCR (Cross-layer QoS Dynamic Codeword Routing) is proposed. It combines the advantages of AODV (Ad-hoc Distance Vector) and DCR (Dynamic Codeword Routing). Basing on the principle of cross-layer, the protocol adapt delay of link,interference between routes and energy consumption as QoS metrics, and provide Differentiated Services for Event-driven Real-time Multimedia streams and Delay-tolerant Data. The algorithm encodes load of routes and nodes aound into a codeword as representative of interference. To meet the QoS requirement of different services, we calculate link cost using inequable weight coefficient in order to protect high priority packets.Finally, we build a cross-layer model for WMSN and evaluate the performance of CLQDCR through simulating. The experimental results demonstrate that the proposed protocol provides differentiated QoS support for heterogeneous traffic. In addition, it maintaines a low end-to-end delay and balances the energy consumption of nodes in the whole network.