Power allocation for energy harvesting in Wireless Body Area Networks

Wireless Body Area Networks (WBANs) are expected to achieve high reliable communications among a large number of sensors. The outage probability can be used to measure the reliability of the WBAN. In this paper, we optimize the outage probability with the harvested energy as constraints. Firstly, the optimal transmit power of the sensor is obtained while considering a single link between an access point (AP) located on the waist and a sensor attached on the wrist over the Rayleigh fading channel. Secondly, an optimization problem is formed to minimize the outage probability. Finally, we convert the non-convex optimization problem into convex solved by the Lagrange multiplier method. Simulations show that the optimization problem is solvable. The outage probability is optimized by performing power allocation at the sensor. And our proposed algorithm achieves minimizing the outage probability when the sensor uses energy harvesting. We also demonstrate that the average outage probability is reduced with the increase of the harvested energy.