Adaptive Beaconing Based MAC Protocol for Sensor Based Wearable System

A sensor-based wearable system is a promising platform to monitor the health and movement of human in real time to improve the quality of life. However, it places stringent requirements on communication delay, energy efficiency, and throughput. In this paper, an adaptive beaconing medium access control (AB-MAC) protocol is proposed to reduce communication delay and improve throughput and energy efficiency for duty cycle-based wearable system. AB-MAC protocol belongs to receiver initiated (RI) MAC protocol, where the sender keeps listening the channel to send data while the receiver sends beacons actively for the preparation of receiving data when it becomes awake. AB-MAC protocol exploits the unbalance energy consumption in the network, where the nodes near the sink (or hub) consume more energy than that of nodes far away from the hub. AB-MAC protocol makes efficient use of the remaining energy of the nodes far away from the hub to send more beacons during the sleep time, which can decrease the sleep delay and improves the energy efficiency and throughput. In addition, the number of beacons that can be sent for the nodes is also obtained based on the remaining energy level. The theoretical analysis is conducted for analyzing the performance of AB-MAC protocol. Furthermore, experimental results are provided, which demonstrate that compared with RI-MAC protocol, AB-MAC protocol can reduce the delay by 32%-51%, increase the throughput by 45%-116%, and improve the energy efficiency by 12%-21% without sacrificing the network lifetime.