Protocol for Controlling Congestion in Wireless Sensor Networks

Congestion control in Wireless Sensor Networks (WSNs) is considered to be a significant challenge and important issue which is related to inherent resource limitation, many-to-one communication scheme and the number of developed sensor nodes. Inasmuch as congestion has significant impacts on (Quality of Service), packet delivery rate, end-to-end delay and energy consumption, it should be controlled. In WSNs, congestion is attributed to parameters such as collision, buffer overflow, channel constraints and the transmission rate. The phenomenon of congestion in WSNs can be handled in two ways: reducing data traffic and increasing network resources. Since packets are not received properly in the intermediate nodes when congestion occurs, hence, appropriate routing towards the sink node cannot be accomplished. The method proposed in this study was intended to sort out the above-mentioned issue of delivering transmitted packets to the sink node. Thus, in this paper we used a hierarchical tree and grid structure to produce an initial topology and Prim's algorithm to find appropriate neighbors. In the proposed method, a hierarchical tree structure was used to produce network topologies and a resource control algorithm was used as a factor to control congestion in wireless sensor networks. In this study, active queue management was used to transmit data with varying priorities. In case congestion occurs, by selecting nodes of the same level and replacing them, the proposed algorithm attempts to reduce congestion. The results of simulation indicated that the proposed algorithm is a highly effective method for congestion control in WSNs in comparing with other congestion control scheme.