Optimal Frame Length to Maximize Energy Efficiency in IEEE 802.15.6 UWB Body Area Networks

Energy efficiency is a major requirement in wireless body area networks (WBANs). In this letter, we optimize the length of the medium access control (MAC) frame body to maximize the energy efficiency in IEEE 802.15.6 ultra-wideband (UWB) WBANs. To achieve this, we derive the probability of packet detection as well as the probability of successful reception of the physical layer header and data payload for the two UWB physical layer modes i.e., the default mode and the high QoS mode. The analysis includes the impact of forward error correction and type II hybrid ARQ on the packet success rate. We further extend the existing model of energy efficiency by incorporating separate energy consumption costs for uplink and downlink channels as well as data transmission and reception. The correctness of the theoretical model is assessed and verified by means of system level simulations, and a closed form expression for optimal frame length is given for the default mode.