Delay Analysis of IEEE 802.15.6 CSMA/CA Mechanism in Duty-Cycling WBANs

Duty-cycle has recently attracted significant research attention due to its paramount importance on energy conservation in Wireless Body Area Networks (WBANs). However, the additional delay resulted from applying duty-cycle is overlooked in most, if not all, of existing work, despite the fundamental importance of the delay in healthcare applications. In order to bridge this gap, we devote this paper to analyzing the delay of IEEE 802.15.6 CSMA/CA mechanism under duty-cycle. Technically, we first explicitly formulate the expressions of the random delay that a sensor node spends on transmitting packets under asynchronous duty- cycling protocol of IEEE 802.15.6 CSMA/CA. Moreover, we mathematically derive the probabilistic characteristics in terms of the expectation and variance of the delay. Furthermore, we conduct elaborate simulations to demonstrate the correctness of the theoretical analysis.