Maximizing Lifetime in Energy-Harvesting WBSN for Health Monitoring Systems Through Dynamic Slots Allocation

摘要

The objective of health monitoring systems is to provide sustainable and high-quality service to subscribers, hence requiring that the system run without interruption for a sufficiently long time. In this paper, we investigate lifetime maximization in Wireless Body Sensor Networks (WBSN) to provide sustainable e-health service with energy harvesting enabled nodes. Maximizing the lifetime is equivalent to minimizing the energy budget within the whole network. To this aim, we optimize the time resource allocation for all involved sensor nodes in order to maintain a sufficient energy level for longer time after each packet transmission. Specifically, we model the energy harvesting process as a discrete-time Markov chain and evaluate the instantaneous energy budget in order to select the node that will occupy a specific time slot. The energy budget is presented as the net energy, which we quantify through the gap between the consumed and harvested energies. Therefore, to achieve sustainability, the idea of the proposed algorithm focuses on prioritizing nodes with a minimum net energy level while offering nodes with high net energy level the opportunity to harvest more energy and increase their capabilities to provide the required energy to continuously submit their data. The proposed algorithm is evaluated in terms of sensor uninterrupted lifetime and packet loss due to energy run out through simulations. The results demonstrate longer uninterrupted lifetime compared to the considered benchmark and low packet loss probability to subscribers.