Robust Energy Efficiency Optimization Algorithm for Health Monitoring System With Wireless Body Area Networks

The electronic health monitoring system, with wireless body area networks (WBANs), is a new technological paradigm that helps early detection of any abnormal physiological signs in a patient's body. In this letter, an optimization problem is formulated to optimize the energy efficiency (EE) of WBAN without requiring the channel state information (CSI) from the transmitting sensor nodes to the aggregator. We utilize a generalized gamma distribution that supports various patient conditions during daily life activities and can efficiently model both everyday and dynamic activities. The optimization problem aims to optimize each sensor transmit power and encoding rate to minimize the EE (measured in J/bits) by considering outage probability and packet retransmission. It is shown that the formulated optimization problem is semi-strictly quasi-convex in each decision variable, and an alternative optimization approach is proposed to determine its solution. The simulation results show that the proposed algorithm is 30% more energy efficient when compared to sub-optimal solution with a constant encoding rate and transmit power of 5 dB, and 0.6 mW, respectively.