Multiantenna Wireless Powered Communication With Cochannel Energy and Information Transfer

This letter studies a multiantenna wireless powered communication (WPC) system with cochannel energy and information transfer, where a wireless device (WD), powered up by wireless energy transfer (WET) from an energy transmitter (ET), communicates to an information receiver (IR) over the same frequency band. We maximize the achievable data rate from the WD to the IR by jointly optimizing the energy beamforming at the ET and the information beamforming at the WD, subject to their individual transmit power constraints. We obtain the optimal solution to this problem in closed form, where the optimal energy beamforming at the ET achieves a best energy-interference tradeoff between maximizing the energy transfer efficiency to the WD and minimizing the cochannel interference to the IR. Numerical results show that our proposed optimal cochannel design is superior to other reference schemes.