New applications made possible by the rapid improvements and miniaturization in hardware has motivated recent developments in Wireless Multimedia Sensor Networks (WMSNs). As multimedia applications produce high volumes of data which require high transmission rates, multimedia traffic is usually high speed. This may cause congestion in the sensor nodes, leading to impairments in the quality of service (QoS) of multimedia applications. Thus, to meet the QoS requirements of multimedia applications, a reliable and fair transport protocol is mandatory. An important function of the transport layer in WMSNs is congestion control. In this paper, we present a new priority-based congestion control protocol, using the queue length as an indication of congestion degree. The rate assignment to each traffic source is based on its priority index as well as its current congestion degree. Simulation results show that the proposed protocol can detect congestion better than the previous mechanisms. Furthermore it has a good achieved priority close to ideal and near-zero packet loss probability, which make it an efficient congestion control protocol for multimedia traffic in WMSNs. As congestion wastes the scarce energy due to a large number of retransmissions and packet drops, so the proposed congestion control protocol can save the energy at each node, given the reduced number of retransmissions and packet drops.

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