Quality of Service Constrained Wirelessly Powered Communication with Multiple Antennas

Wirelessly powered communication enables data transmission even for energy-constrained users. On the other hand, quality of service constrained communication is important for modern systems with diverse requirements. Combing both is promising for future Internet of things such as sensor networks, smart homes, and wearable electronics. However, due to the uplink-downlink coupling in wirelessly powered networks, it is challenging to determine the minimum network transmit power subject to quality of service constraints. In response to it, this paper derives the optimal network transmit power for a quality of service constrained wirelessly powered network with multiple antennas. The optimal solution is obtained based on a two-step approach consisting of multi-criterion optimization and inner approximation, which only requires moderate complexity. Our numerical results on total transmit power validate the analysis and illustrate the fast convergence of the algorithm.