Improving Performance and Fairness in IEEE 802.15.4 Networks with Capture Effect

In IEEE 802.15.4 networks, nodes access the medium using a CSMA/CA method to avoid collisions. As the networks use robust physical layers, they benefit from the capture effect: a receiver can correctly receive a frame even if it collides with another transmission. The capture effect and the access scheme result in significant unfairness between nodes depending on their positions. In this paper, we propose new adaptive medium access control algorithms to improve fairness and performance. The algorithms adapt the contention parameters and transmission power depending on the observed busy channel and transmission failure rates to achieve a target frame delivery rate. We have carried out extensive simulations to evaluate the performance gains of the algorithms compared to legacy IEEE 802.15.4 with static transmission power and default contention parameters. Simulations show important improvement in terms of the frame delivery rate, energy consumption, and fairness.