Congestion Control Mechanism Based on Dual Threshold DI-RED for WSNs

In wireless sensor networks (WSNs), traffic flow congestion can reduce network performance. We propose a congestion control method for WSNs that use a cache state with a dual threshold in the router buffer to control congestion. In addition, the congestion is controlled by the channel transmission state that is monitored by the queuing variation tendency and the transmission rate. Based on the active queue management mechanism, a dual threshold with the double index random early detection (DI-RED) model is established to improve network performance. We also present the congestion control algorithm of DI-RED model to ensure the perfect actualization. By solving the DI-RED model, a series of channel indicators is obtained, including packet loss rate, average queue length, delay and throughput. Simulation results show that the proposed DI-RED model is more stable and demonstrates better control, which can overcome the parameter sensitivity of the RED mechanism. The proposed model realises a reasonable tradeoff between network performance and packet dropping probability, which effectively avoids degraded network performance caused by pursuing a lower packet dropping probability. The results are important when selecting a congestion control mechanism and parameter settings for WSNs.