Design & implementation of distributed congestion control scheme for heterogeneous traffic in wireless sensor networks

Recently emerging wireless sensor technologies integrate different types of sensor nodes in a network for information collection. The heterogeneous Wireless Sensor Network (WSN) imposes complex design challenges as nodes in such a network often have different requirements in terms of latency and bandwidth. Therefore, the channel access for nodes needs to be managed ensuring differentiated quality of service for each priority. This paper aims at developing and evaluating a distributed congestion control scheme for CSMA to make it feasible for prioritized heterogeneous traffic. For this purpose, a model earlier developed for 802.15.4 has been enhanced and integrated with the duty-cycled CSMA. Heterogeneous Traffic of three different priorities has been used for evaluating the performance of proposed scheme. The scheme has been implemented in nes-C for the mica2 platform. It has been revealed that for heterogeneous traffic, the throughput of CSMA integrated with our proposed scheme has a significant advantage over basic CSMA.