Rational Allocation of Guaranteed Time Slots to Support Real-Time Traffic in Wireless Body Area Networks

Background: The main requirement of Wireless Body Area Network (WBAN) is on-time delivery of vital signs that are sensed through the delay-sensitive biological sensors that are implanted in the body of the patient being monitored by the central gateway. The Medium Access Control (MAC) protocol standard IEEE 802.15.4 supports real-time data delivery through its unique feature called Guaranteed Time Slot (GTS) under its beacon-enabled mode. This protocol is considered suitable for the WBAN Scenario. However, as per the standard, IEEE 802.15.4 uses a simple and straightforward First Come First Served (FCFS) mechanism to distribute GTS slots among the contender nodes. This kind of blindfolded allocation of GTS slots results in poor utilization of bandwidth and also prevents the delay-sensitive sensor nodes from effectively utilizing the contention-free slots. Objective: The main objective of this work is to provide a solution for the unfair allocation of GTS slots in the beacon-enabled mode of the IEEE 802.15.4 standard in WBAN. Methods: We propose a Rational Allocation of Guaranteed Time Slot (RAGTS) protocol that distributes the available GTS slots based on the delay-sensitivity of the contender nodes. Results: A series of simulation experiments has been performed to assess the performance of our proposed RAGTS protocol. The simulations capture the dynamic nature of the real-time deadlines associated with sensor traffic. Through simulations, we show that our proposed RAGTS protocol appears to be more stable in terms of various performance metrics than that of the FCFS nature of the GTS allocation technique. Conclusion: In this article, we introduced the RAGTS scheme that enhances the real-time traffic feature of the beacon-enabled mode of IEEE 802.15.4 MAC.