Exploiting BS Antenna Tilt for SWIPT in 3-D Massive MIMO Systems

In this letter, we study simultaneous wireless information and power transfer (SWIPT) in a 3-D massive multiple-input multiple-output system. In order to exploit the vertical domain and increase SWIPT efficiency, the base station antenna tilt is jointly optimized with power allocation and power splitting ratios for minimizing the transmit power with signal-to-interference-plus-noise ratio and harvested power constraints. We propose an iterative algorithm to obtain the optimized solutions. Simulations show that the performance of our proposal is close to that of the optimums from brute-force search and outperforms the scheme with an adjustable tilt in conventional systems.