A QoS-aware congestion control mechanism for wireless multimedia sensor networks

The amount of data produced by multimedia sensor nodes (such as video/audio sensors), is considerably huge comparing with the data of scalar sensor nodes. The great numbers of data packets have to be forwarded by the network nodes hop by hop to reach the final destination(s). Accordingly, the problem of congestion in wireless multimedia sensor networks (WMSNs) is more serious challenge than in traditional sensor networks. In this paper, a distributed method for congestion control in WMSNs is proposed. A three-level buffer structure is proposed for nodes and the sensing area is divided to the optimized number of zones; a mobile sink along with a coordinator node are employed in each zone. Moreover, the proposed method comprises a novel tree creation procedure. After detection of an occurred congestion, a local binary tree for the congested node is established in the corresponding zone to mitigate the congestion. The next possible congested nodes of the zone use the created tree to send their packets. In the case of the created tree cannot solve the problem of congestion of a zone node with undertaking the quality of multimedia data, the mobile sink of the zone is utilized. The simulation results and comparisons of the proposed method with other works from throughput, consumed energy, delay and SNR points of view, demonstrate the efficiency of the proposed method in mitigating the congestions with keeping the quality of data and service.