A Dual-buffer Based Congestion Control Algorithm for Wireless Multimedia Sensor Networks

Data traffic congestion is one of the most important issues in wireless multimedia sensor networks (WMSNs). Congestion in WMSNs causes many problems, e.g. long delay, high packet loss. Therefore, it is very important to solve the congestion problem in WMSNs. To address this issue, we propose a novel traffic congestion control algorithm based on dual buffer detection. The proposed algorithm reveals the implementation of a networked system for joint rate control and error control of video over resource-constrained embedded devices. First, it uses a combination of two different congestion indicators to precisely detect congestion. One of the indicators is buffer occupancy, and the other one is buffer occupancy change rate. The proposed algorithm analyzes the buffer occupancy and its change rate at each node to handle congestion in an efficient manner. Second, we develop a feedback-based rate controller to enhance the received video quality. It is shown that the developed rate controller can adaptively adjust the sending rates of nodes in congestion situation. Finally, we present different retransmission mechanisms for different kinds of packets. After a certain number of failures in retransmission, the lost packets are saved temporarily and retransmitted later on when free channel is available to further alleviate congestion. The proposed algorithm is implemented on 13 sensor nodes. It is extensively evaluated on a multi-hop WMSNs. The experiment results show that the proposed algorithm outperforms the previous approaches in terms of rate control and packet loss.