Utility maximization for wirelessly powered multiple-antenna systems

We consider a multi-input-single-output (MISO) system where a wireless power transmitter sends wireless power to a receiver via beamforming using the estimated channel, and the power receiver uses the harvested energy to power some applications. We consider transmissions based on frames each of which consists of the channel estimation phase, the feedback phase, the wireless power transfer phase, as well as the energy utilization phase. The feedback time is assumed to be negligible. In this paper, we maximize the utility of the harvested energy, by jointly optimizing the time resource allocated for channel estimation, wireless power transfer, as well as the energy utilization. In particular, we consider two typical application scenarios in which the energy-harvesting receiver uses the harvested energy to perform wireless transmission or sensing. The optimal time allocation is derived to maximize the net average information rate or maximize the sensing accuracy. The analysis results are validated by numerical simulations.