Throughput Maximization for Wireless-Powered Buffer-Aided Cooperative Relaying Systems

We consider a wireless-powered relaying system in which the relay nodes (RNs) that have no embedded power supply are charged by the radio frequency signal transmitted by a power beacon. Each RN is assumed to possess a buffer and can temporarily store the information received from the source node. Based on this assumption, we propose an adaptive transmission scheme, in which each RN adaptively switches between two transmission modes. To maximize the system throughput, a joint node-and-mode selection scheme in which the RN and its transmission mode are jointly selected in each time slot is investigated. For the general system setup, some analytical results are obtained, which provide useful insights in finding the optimal joint node-and-mode selection scheme. Following this, the analysis is applied to two specific systems, the single RN system and the multiple RNs system with a symmetric channel. For these system setups, the system throughput and the corresponding optimal transmission scheme are obtained in the closed-form expressions. Numerical results show that the throughput of the wireless-powered relaying system can be improved by using the proposed transmission schemes.