Cooperative Power Control and Beamforming Design for Multi-Source Enabled Wireless Power Transfer Networks

In this paper, we study wireless power transfer (WPT) network with multiple WPT stations and multiple low-power devices. With installed uniform linear antenna array, WPT stations emit independent radio-frequency (RF) signals for cooperatively harvesting all devices. Analog beamforming has been applied for efficiently concentrating the emitted energy. Combining beamforming with multi-source WPT, we characterize out the harvested power for each device based on a practically nonlinear energy harvesting (EH) model. Allowing different beamforming schemes in multiple time slots, we formulate a joint power control and beamforming design problem fairly maximizing the total harvested energy at all devices. To tackle the problem non-convexity, we apply proved convexity in both antenna gain model and nonlinear EH model, and build convex problem approximation, which enables an iterative algorithm efficiently converging to a suboptimal solution. At last, we verify our proposed algorithm and highlight the WPT profits of our proposed solution via numerical results.