2TM-MAC: A Two-Tier Multi-Channel Interference Mitigation MAC Protocol for Coexisting WBANs

Wireless Body Area Networks (WBANs) have been developed rapidly with the increasing popularity of wireless network and wearable technologies. The inherent characteristics of convenience and efficiency for health monitoring facilitate the depth and width of WBAN applications. However, the inter-WBAN interference problem affects the network performance in intensive WBAN scenarios, degrading reliability and increasing latency of health data. In this paper, we propose a Two-Tier Multi-channel Medium Access Control (2TM-MAC) protocol with interference mitigation for reliable health monitoring. Specially, the 2TM-MAC establishes an inter-WBAN interference matrix for every WBAN to show the mutual interference among coexisting WBANs. We design a multi-channel selection algorithm at the first tier to select different numbers of channels for each WBAN to avoid inter-WBAN interference and collisions. At the second tier, the hub of each WBAN schedules the available channels assigned from the first tier to sensor nodes according to their traffic requirements, mitigating the intra-WBAN interference as well. 2TM-MAC protocol enhances the reliability of emergency data and service experience in healthcare applications. Simulation results show the 2TM-MAC protocol significantly improves the network throughput and decreases the average packet delay compared with IEEE 802.15.6 for densely deployed coexisting WBANs scenarios.