Background: According to WHO, Cardiovascular diseases are the major cause of death worldwide. Due to the increase in cardiac diseases, miniaturized and energy efficient remote cardiac monitoring systems are required.
Objective: To develop an Activity Aware Energy Efficient priority based Multi Patient Monitoring protocol for Body Sensor Networks to monitor physiological signals continuously. The protocol must also be adaptive to allow for new connections and to renegotiate the nodes services.
Method: In this protocol, the ECG signals of multiple patients are monitored one after another in a cyclic order. Slots are allotted to each patient by means of a dynamic TDMA scheme where the slot duration is dependent upon the criticality of the patient. A Network configuration slot is provided at the end of each frame to reconfigure the network. Using the wearer's activity level, the sensor dynamically manages its activities namely, sampling of the ECG sensor, processing of the data, and wireless transmission to minimize overall power consumption. Additional energy efficiency is achieved by assigning priorities to the devices connected in the network and turning them on and off periodically based on their priorities.
Results: The protocol is implemented on Shimmer nodes and ECG signals of N patients are monitored. The reconfiguration of the node's priority and sampling rate based on the health condition of the patient are demonstrated. A comparison of energy consumption, packet delivery ratio and battery life time is made.
Conclusions: Energy consumption and nodes lifetime are the parameters to be optimized in the case of BSN. The AAEEPMPM protocol for BSN has been designed and implemented in hardware platform for energy efficiency. The results obtained from the BSN shows that this protocol has higher energy efficiency and provides better lifetime for the network.
Keywords: Priority based ECG monitoring; dynamic TDMA; energy efficiency; network configuration slot; wireless body sensor network.