Convergecast in Wireless Body Area Networks.

Wireless Body Area Networks (WBAN) is a recent challenging area in the health monitoring domain. There are several concerns in this area ranging from energy efficient communication to designing delays efficient protocols that support nodes dynamicity induced by human body mobility. This paper focuses on the convergecast or data gathering protocols in WBAN. Our contribution is twofold. First, we extensively analyze the impact of postural body mobility on various classes of multi-hop convergecast strategies. Our study does not limit itself to the existing state-of-the-art in WBAN, we adapted to WBAN settings strategies from the areas of Delay Tolerant Networks (DTN) and Wireless Sensor Networks (WSN). We evaluate these strategies in terms of resilience to the human mobility, end-to-end delay and energy consumption, via the OMNeT++ simulator that we enriched with a realistic channel model issued from the recent research on biomedical and health informatics. Our simulations show that strategies that perform well in DTN and WSN cannot be just extrapolated to WBAN without a deeper investigation. That is, existing convergecast strategies for DTN or WSN do not perform well with postural body movements because of the topological partitioning provoked by important link attenuations due to signal obstructions either by clothes or by the body itself. Secondly, our extensive simulations give us valuable insights and directions for designing a novel convergecast strategy for WBAN called Hybrid that presents a good compromise in terms of resiliency to mobility, end-to-end delay and energy consumption.