TMP: Tele-Medicine Protocol for Slotted 802.15.4 with Duty-Cycle Optimization in Wireless Body Area Sensor Networks

Recently, adaptive duty cycle-based medium access control (MAC) protocols based on the IEEE 802.15.4 standard have been proposed to address the quality of service (QoS) requirements, including a specified and combined set of time bounded data transmission services, data rate, reliability, and energy consumption for wireless body area sensor networks. However, the current protocols suffer limitations in the context of providing a combined set of QoS. Moreover, for efficient energy consumption, these protocols adjust duty cycle values on estimations, such as active periods, buffer occupancy, and collision rates. These estimations consume resources in terms of delay and energy, which makes them hardly acceptable for medical applications. In this context, we propose a tele-medicine protocol (TMP) under the IEEE 802.15.4 slotted CSMA/CA with beacon enabled mode on the basis of a novel idea which combines two optimizations methods, i.e., MAC layer parameter tuning optimization and duty cycle optimization. The TMP duty cycle is adjusted by three factors: offered network traffic load, delay-reliability factor, and superframe duration. The proposed protocol provides the required set of QoS (delay, reliability, and efficient energy consumption) at the same time for patient monitoring applications. Performance of the proposed protocol is computed on the basis of average end-to-end delay, reliability, packet delivery ratio, collision rate, and energy consumption by varying the number of nodes and offered network traffic. The TMP performed well in terms of delay, reliability, energy consumption, and collision rate in comparison of the other existing protocols under the constraints of patient monitoring applications.