Fuzzy logic based congestion control for progressive image transmission over wireless sensor networks

The availability of low-cost camera hardware has enabled the Wireless Multimedia Sensor Networks (WMSNs), and has made it possible to develop multimedia applications such as surveillance systems, traffic control systems, environment monitoring and object tracking. Unlike scalar data, multimedia requires higher bandwidth due to the larger amount of information to be transmitted. Congestion is a challenging problem for Wireless Sensor Networks (WSNs) due to waste of scarce communication resources and reduction energy efficiency. Compared to traditional WSNs, the probability of congestion occurrence in WMSNs is higher due to the high volume of data arising from multimedia streaming. In this thesis, problems for multimedia transmission over WMSNs are examined and Sensor fUzzy-based Image Transmission (SUIT); a new cross-layer progressive image transport protocol is proposed as a solution. SUIT provides fuzzy logic based congestion estimation and an efficient congestion mitigation technique which decreases the image quality on-the-fly to an acceptable level. In case of congestion, SUIT drops some packets of the frames in a smart way and thus transmit frames to the sink with lower, but acceptable quality. In this way, SUIT improves the continuity of the video streaming. The performance of SUIT is evaluated by comparing it with two example transport protocols proposed for WSNs. According to the simulation results, SUIT provides better energy consumption, frame delivery, frame loss and frame latency performance than its competitors.