ATLAS: A Traffic Load Aware Sensor MAC Design for Collaborative Body Area Sensor Networks

Abstract: In collaborative body sensor networks, namely wireless body area networks(WBANs), each of the physical sensor applications is used to collaboratively monitor thehealth status of the human body. The applications of WBANs comprise diverse and dynamictraffic loads such as very low-rate periodic monitoring (i.e., observation) data and high-ratetraffic including event-triggered bursts. Therefore, in designing a medium access control(MAC) protocol for WBANs, energy conservation should be the primary concern duringlow-traffic periods, whereas a balance between satisfying high-throughput demand andefficient energy usage is necessary during high-traffic times. In this paper, we design atraffic load-aware innovative MAC solution for WBANs, called ATLAS. The design exploitsthe superframe structure of the IEEE 802.15.4 standard, and it adaptively uses the contentionaccess period (CAP), contention free period (CFP) and inactive period (IP) of the superframebased on estimated traffic load, by applying a dynamic “wh” (whenever which is required)approach. Unlike earlier work, the proposed MAC design includes load estimation fornetwork load-status awareness and a multi-hop communication pattern in order to preventenergy loss associated with long range transmission. Finally, ATLAS is evaluated throughextensive simulations in ns-2 and the results demonstrate the effectiveness of the protocol.