MAC Protocol for Duty-Cycling WBSNs with Concurrent Traffic

Wireless body sensor networks (WBSNs) have been deployed to monitor the health condition of patients. In these applications, multiple sensors are required to report the real-time data to the sink such that a physician can diagnose accurately, especially for intensive care patients, which boosts the convergecast traffic load and increases the collision probability. However, the existing protocols cannot operate effectively under such concurrent traffic load. To bridge this gap, we present a novel two-phase receiver-initiated MAC protocol for concurrent traffic based on asynchronous duty cycling, called C-MAC. Technically, C-MAC in the first phase employs the carrier sense multiple access with collision avoidance (CSMA/CA) of IEEE 802.15.6 standard and designs an ordering-based communication algorithm to effectively avoid collisions. Moreover, C-MAC enables sensor nodes to switch to standby mode (SBM) to avoid idle listening and overhearing in the second phase. Furthermore, theoretically, we explicitly formulate the mathematical expressions of the random delay and energy consumption of C-MAC. Finally, we conduct the extensive numerical analysis and simulation to demonstrate the correctness of theoretical results and the better effectiveness and efficiency of C-MAC than that of RI-MAC and A-MAC in terms of transmission delay and energy consumption.