Study Of Congestion Control In Wireless Sensor And Actor Networks

Network congestion has long been an important research topic for people. And great progress has been made in the traditional end to end network congestion control research area. The rise of the wireless sensor network congestion control study also presented new challenges. In WSN, dense deployment of nodes, many to one communication mode, the wireless link interference, dynamic changes of network topology, limited resources of node and other factors, all may lead to congestion. Congestion leads to both waste of communication and energy resources of the sensor nodes and also hampers the reliability of networks. Compared with the traditional wired Internet, congestion control in sensor networks is even more important, while congestion control algorithm has higher requirements. In recent years, many researchers have begun to study congestion in wireless sensor network control problem, many algorithms, such as CODA, ESRT, etc.Wireless Sensor and Actor Networks (WSANs) is a new type of wireless sensor networks, which refer to a group of sensors and actors linked by wireless medium to perform distributed and acting tasks. In WSANs, sensor nodes collect information about the physical world, while actors take action decisions and perform appropriate actions upon the environment. The applications of WSANs span a very wide range, including real-time target tracking and surveillance, homeland security, and biological or chemical attack detection. The new requirements of congestion control in WSANs have been raised owing to the new network architecture and the new real-time and reliable event transport requirements of WSANs, and then some appropriate protocols have been presented recently.In this paper, the author analyzes the characteristics of congestion in WSN and WSANs firstly, and then studies the congestion control algorithms presented by other researcher recently. The author puts the emphasis on a protocol called RT2, and presents a new congestion control algorithm called CCBER based on RT2, which makes consideration for event reliability in WSANs. In CCBER, the model of event reliability in WSANs is established, and the actor nodes calculate the criticality of sensor nodes on event area according to the data packet received. CCBER presents a more accurate and reasonable rate adjustment strategy, which seeks the maximal event reliability with no congestion in networks.