Information and energy cooperation in OFDM relaying

In this paper, we consider simultaneous wireless information and power transfer (SWIPT) in an orthogonal frequency-division multiplexing (OFDM) relaying system, where a source node transfers information and a fraction of power simultaneously over OFDM to a relay node, and the relay node uses the harvested power from the source node to forward the source information to the destination. To support such simultaneous information and energy cooperation, we propose two transmission protocols, namely power splitting (PS) relaying protocol and the transmission mode adaptation (TMA) protocol for without/with the source-destination link, respectively. For both transmission protocols, joint resource allocation problems are formulated to maximize the system throughput. By using the Lagrange dual method, we develop efficient algorithms to find the optimal polices of the nonconvex optimization problems.