Distance Adaptive Contention Window Mechanism for Wireless Sensor Networks

Recently, Wireless Sensor Network (WSN) is a fast growing technology, which collects various data for user and provides user with requested information in timely. A sensor network has a Many-to-One communication architecture which each sensor node transmits its sensed data to the sink node. However, most existing sensor network protocols do not consider Many-to-One paradigm and all sensor nodes access the channel with same probability. In this paper, we propose Distance Adaptive Contention Window (DACW) modified IEEE 802.15.4 standard. The key mechanism of DCAW is a dynamical channel access MAC protocol, which is to adjust Contention Window (CW) according to the hop count distance to sink and traffic condition. With DACW, each sensor node can achieve self-routing capability with low overhead and performance enhancement. Furthermore, DACW can be easily applied to existing routing protocols without additional overhead and shows that its performance is better than the existing MAC protocol by the simulation