Effects of access phases lengths on performance of IEEE 802.15.6 CSMA/CA

In this paper, we study interplay of prioritizing mechanisms in recently released IEEE 802.15.6 standard for Wireless Body Area Networks (WBANs). Among eight User Priorities (UPs) we study the impact of access phases lengths and CSMA/CA mechanism on the network performance. We consider a star-topology single-hop WBAN in which the hub operates in beacon mode with superframe boundaries. Our study is conducted in saturation regime and an error prone channel in order to indicate performance bounds for all UPs. We have developed an analytical model for the CSMA/CA-based Medium Access Control (MAC) layer of IEEE 802.15.6 which includes Markov chain and probabilistic models for all UPs. In order to validate the analytical model we have developed a simulation model in OPNET. We investigate the effectiveness of deploying exclusive access phases and second random access phase on the network performance. We also examine the medium utilization and normalized throughputs of all UPs. Obtained performance bounds indicate potential tradeoff between the prioritizing parameters which affect the saturation throughputs.