Node Selection Technique for Distributed Beamforming in Green Cognitive Radio Networks

Abstract

The wide deployment of wireless sensor nodes for varieties of applications calls the need for distributed beamforming as a cooperative scheme to efficiently use spectrum, to improve communication range and to save precious battery power during transmission. Given that there are a large set of cooperative cognitive radio users, ensuring the minimal energy is consumed while keeping the interference received by primary users below a given regulatory limit is crucial to maintain the green aspect of Cognitive Radio Sensor Network. The major research question is how to develop an efficient node selection method that allows to keep the energy consumption at the minimum and while keeping the interference regulations of primary users. In this thesis, an efficient node selection method which allows maintaining the Green aspect of the network is proposed. The node selection method is used to save significant amount of energy per single transmission. Furthermore, the impact of ambiguous location information in distributed beamforming is investigated. The statistical characterization of the phase error at the beamforming nodes is studied. A simple solution that leads to minimize the degradative impact of location ambiguity is given.