A new scheme of dynamic power allocation in wireless powered communication

In this article, we propose a new generalized selection transmit scheme (GSTS) for wireless powered communication (WPC), where data access point (DAP) is powered by energy access point (EAP) to communicate with wireless device (WD). Theoretically speaking, allocating all harvesting energy to the antenna with the best channel gain will achieve the optimal performance. While the harvesting energy is dynamic and may exceed the power limitation of single antenna, we should allocate the harvesting energy to the best antennas subset with the minimum number of antennas. That is GSTS. For GSTS, we derive the new closed-form probability density function (PDF) of signal to noise ratio (SNR). According to the derived PDF, the approximate outage probability is derived. In order to depict the trend of outage probability at high SNR area, the diversity order is derived. It is determined by the minimum one of the transmit antenna number of EAP and that of DAP. Besides, the influence of line-of-sight (LOS) component in wireless power transfer (WPT) is also discussed.