Time-Division Energy Beamforming for Multiuser Wireless Power Transfer With Non-Linear Energy Harvesting

Energy beamforming has emerged as a promising technique for enhancing the energy transfer efficiency of radio-frequency (RF) enabled wireless power (WPT). However, performance conventional may seriously degrade due to non-linear RF direct current (DC) conversion at receivers (ERs). To tackle this issue, letter proposes new time-division scheme, in which different matrices (of high ranks general) are time shared exploit “convex-concave” shape RF-DC relation ERs. In particular, we maximize minimum harvested DC among all ERs, by jointly optimizing and corresponding allocation subject given charging duration (e.g., second). solve formulated non-convex min-DC-energy maximization problem, propose an efficient solution using techniques alternating optimization successive convex approximation (SCA). Numerical results show that proposed design indeed outperforms multi-beam time-division-multiple-access (TDMA)-based transmissions.