An improvement of IEEE 802.15.4 MAC protocol in high-density wireless sensor networks

This paper proposes a new backoff algorithm for IEEE 802.15.4 MAC protocolin high-density wireless sensor networks, which is based on two-level channel information mined by nodes locally, namely channel busyness rate and packet collision rate. According to the two-level periodical renewing information, each node can achieve real-time and comprehensive network traffic load status, and then the node adjusts backoff window properly to maximize the channel utilization. In order to avoid packet congestion, backoff window of each node shrinks linearly rather than exponentially as traffic load is sensed light, which can make transmission probability of nodes fluctuate around the optimal probability for p-persistent CSMA model. Compared with IEEE 802.15.4 standard and KBE algorithm, the simulation experiments on NS-2 platform show that our proposed scheme significantly improve the network throughput.