User-Centric Energy Efficiency of Distributed Antenna Systems with Wireless Power Transfer

In this paper, we study energy-efficient resource allocation in distributed antenna system (DAS) with wireless power transfer, where time-division multiple access (TDMA) is adopted for downlink multiuser information transmission. In particular, when a user is scheduled to receive information, other users harvest energy at the same time using the same signal. We consider the user-centric energy efficiency (UC-EE) as our performance metric, which has the sum-of-ratios structure and thus is nonconvex. We transform the nonconvex problem into an equivalently tractable problem by using suitable mathematical tools and then develop an iterative algorithm to find the globally optimal solution. Simulation results demonstrate the superiority of the proposed method compared with the benchmark schemes.