An energy-efficient multiconstrained QoS aware MAC protocol for body sensor networks

One of the most challenging jobs in designing a Medium Access Control (MAC) protocol for Body Sensor Networks (BSNs) is to achieve QoS requirements for heterogeneous traffics generated from various sensors. Increasing the energy-efficiency of the network should be kept in mind while doing this. Physiological data monitoring applications generate different types of traffic including multimedia data packets. These heterogeneous traffics should be treated differently by an underlying communication protocol, allowing the transmission schedule of these traffic types based on their priorities. In this paper, we present an energy-efficient multiconstrained QoS aware MAC protocol, namely eMC-MAC, wherein the medium access control is designed based on traffic prioritization. We have redefined the superframe structure in such a way that the critical data packets are transmitted earlier than other packets. In our proposed eMC-MAC protocol, we have introduced minislots during CFP (Contention Free Period), where requests for urgent packets are collected to the coordinator node in an energy-efficient way. We also develop an energy-efficient algorithm for preempting allocated data transmission slots to facilitate transmission of packets with higher priority. Thus, the proposed eMC-MAC protocol delivers emergency data packets to the coordinator with reduced delay. We have evaluated the effectiveness of our eMC-MAC protocol through extensive simulations in ns-3. The simulation results have shown that it outperforms a number of state-of-the-art MAC protocols for BSNs.