A priority-queue dominated and delay-energy guaranteed MAC superframe structure for WBANs to deal with various emergency traffic of pilgrims during hajj: An analytical model

Abstract

In recent times, IEEE 802.1.5.6 based wireless body sensor networks (WBANs) are being deployed in various medical and healthcare centres for providing quick and real-time health facilities among the patients. Every year during Hajj several millions of pilgrims gather together at overcrowded ritual site ‘Kaaba’ and its surrounding places in Makkah. Ensuring the best healthcare facilities and services among the pilgrims those who are suffering from a variety of critical conditions and illness including chronic diseases; sudden illness, trauma and accidents at the congested environment is a demanding research issue because lack of proper healthcare facilities may worsen the life of pilgrims. In our research, we define the emergency medical data into five different criticality levels which are aperiodic or random and require immediate transmission to the healthcare stations for further actions. Based on the data criticality level a priority-criticality index table and a modified superframe structure for medium access control (MAC) protocol are developed. Critical or emergency data is obligatory to be transmitted ahead of other noncritical traffic as delay in its transmission may impede human life. But, the problem may occur when more than one emergency data from different sensors aggregate to the coordinator for further transmission to the healthcare stations through exclusive access period-EAP slot of MAC. For smooth, low delay and energy efficient data transmission we propose an analytical method based on M/M/1 priority-queuing system to provide delay-energy guaranteed QoS at MAC level in our research. The Poisson distribution process has been used to analyse the packet arrival rate of each queue. In this research, M/M/1 queuing system is used to investigate five different priority-queues for five emergency traffics. Emergency traffic is defined and prioritised through the criticality level of pilgrims’ medical problems as being generated by body sensors. From the mathematical analysis, we have seen that the medical data with the highest priority should not stay at the queue for a long time which decreases the queuing delay at the system. Moreover, for energy efficient data transmission, we propose a sleep/idle-wakeup mechanism that reduces unnecessary energy consumption. An extensive analytical approach through mathematical model shows the better performance comparing to the default IEEE 802.15.6 standard which assumes the sensor nodes are awake all the time. Finally, in our future research, extensive experimental work will be conducted to corroborate and validate the analytical findings which are mentioned in the discussion and future work section. © 2005 – ongoing JATIT & LLS.