Beam-Pattern Synthesis for Circular Arrays with Sensor Selection for WBAN via Convex Optimization

Wireless body area network (WBAN) is emerging as a powerful tool for health management which is characterized by a modest number of sensors placed on or around human bodies. Since sensor nodes are generally battery-powered devices, reducing sensor node power consumption to improve the efficiency and save sensor usage costs is crucial. In this paper, a convex optimization method based beam-pattern synthesis with sensor selection is proposed for circular sparse arrays, which can be regarded as the model of the head of human. Our goal is two-fold: minimize the number of sensors while achieving the best peak level of side-lobe. The method can solve uniformly spaced circular arrays with inter-element spacings about half- wavelength in order to satisfy the performance of the beam-pattern. Based on the one circular ring array, we propose two different configuration modes, one is uniform circular array and the other is concentric circular array. Simulations are shown using up to a few hundred sensors to illustrate the practicality of the proposed algorithm.