Simultaneous transfer of energy and information for MIMO-OFDM relay system

This paper investigates performance tradeoffs between energy and information transfer in a relay based two-hop wireless system involving an energy harvesting receiver. The source and relay nodes of the two-hop amplify-and-forward (AF) system employ orthogonal space-time block codes along with orthogonal frequency-division multiplexing (OFDM) scheme. The joint optimal source and relay precoders over the subchannels in frequencies are designed to achieve different tradeoffs between the overall energy transfer capability and the information rate, which are characterized by the boundary of the so-called rate-energy (R-E) region. The effect of various parameters on the boundary of the R-E region is demonstrated for different frequency selective channel models.