Real-time Adaptive Medium Access Control Protocol to Improve Transmission Efficiency in Body Sensor Networks

The applications of wireless sensing technology in health monitoring and diagnosis have increased dramatically. These applications have improved the quality of life and allowed medical practitioners to access patients information remotely and timely. However, the wireless communication between the sensing devices can be interfered by body movement. To guarantee data availability and recognition accuracy, each node has to either utilize a high transmission power or involve a packet retransmission mechanism. Increasing the transmission power of a sensor node increases energy overheads and communication range. Larger communication range can produce additional interference with other nodes on the body. Packet retransmission, on the other hand, complicates on-body sensor nodes' MAC layer and increases energy overheads. In this paper, we propose an Adaptive Medium Access Control protocol to improve the delivery rate by duty-cycling the transmission radio according to the predicted activities. We perform extensive experiments to evaluate and compare the protocol against B-MAC, OMAC and OTP using real sensor nodes attached to 50 participants. The results show that the proposed system can achieve a higher packet delivery than B-MAC, OMAC and OTP without additional energy consumption