Empirical evaluation of adapting IEEE 802.15.4 contention windows for maximum performance

The IEEE 802.15.4 standard specifies the most recommended medium access control (MAC) protocol for Wireless Sensor Networks (WSNs). The contention-based access scheme of the MAC is driven by a Carrier Sense Multiple Access with Collision Avoidance (CSMA-CA) algorithm. In this paper, we evaluate the performance of the CSMA-CA algorithm for indoor WSNs by using an experimental testbed. We set up trials to test the default parameters of the IEEE 802.15.4 for saturated and unsaturated conditions of arriving packets. In particular, we demonstrate that the experimental results accurately match the predictions of an analytical model for the CSMA-CA algorithm, though the latter assumes ideal transmission over the wireless medium. Finally, we show that data delivery ratio and throughput could be improved by opting during the contention for different window sizes compared to the default values of the standard specification.