A backoff copying scheme for contention resolution in wireless sensor networks

This paper aims at improving the throughput and fairness of the wireless sensor networks (WSN). Due to the disproportionate larger number of packets accumulated in the sensors that are closer to the base station, it's necessary to have a better contention resolution scheme to improve the throughput and fairness in WSN. In this paper, we propose a new mechanism named BCCR (Backoff Copying for Contention Resolution), which is targeted to a system-wide proportional fairness in WSN. The new method is designed particularly for a many-to-one data collection tree structure, employing a mechanism that translates a fairness model into contention resolution. In BCCR, the size of the backoff window is dynamically adjusted to the channel allocation rate of the flow sent by the sensors. And the backoff algorithm does not focus on each node, but focus on each region which is divided according to the traffic flow contention. In every contention region, sensor nodes will share the same backoff window by a copying scheme. With extensive simulations and testbed experiments, we show that BCCR can achieve the expected fairness and throughput increase over the traditional CSMA, especially when the network is congested.