Adaptive TDMA-based MAC protocol in energy harvesting wireless body area network for mobile health

This paper investigates the problem of link scheduling in a single-hop energy harvesting wireless body area network (EH-WBANs) where sensor devices's energy harvesting rates and data rates are spatially heterogeneous and temporally variant. To maximize the channel utilization with the lifetime operation, an adaptive TDMA-based protocol (AT-MAC) is proposed, which is suitable for communication in an EH-WBAN for remote monitoring of physiological signals. In this protocol, a duty cycle can be dynamically adjusted to maintain the harvested energy amount, which is always greater than power consumption. Also, a novel time-slot allocation algorithm is designed to automatically adjust duty cycle with various data traffic and harvesting rates. This algorithm is decomposed into two sub-processes: predistribution of time-slot and redistribution of time-slot. The former process takes the information of energy harvesting rates into account, regardless of the rates varying in a nondeterministic manner and among various sensor nodes. For the latter process, the number of distributed time slots will be further adjusted to cope with data traffic of spatially heterogeneousness. Simulation results demonstrate the proposed protocal is a promising candidate for realizing the lifetime operation in EH-WBANs.