Optimal precoding for simultaneous information and power transfer in MIMO relay networks

In this paper, we focus on the problem of optimal precoding for simultaneous wireless information and power transfer (SWIPT) in a two-hop decode-and-forward (DF) multiple-input multiple-output (MIMO) relay network, which consists of a source, a relay station, an information decoding (ID) receiver and an energy harvesting (EH) receiver. Each node in this relay network is assumed to employ multiple antennas. In order to better character the optimal tradeoff between simultaneous information and power transfer in MIMO relay networks, a 3D rate-energy (R-E) region is first defined. In addition, an algorithm based on convex programming is proposed to effectively compute the R-E region. Finally, numerical simulations are provided to evaluate the proposed algorithm. It is found that the optimal tradeoff between the maximum information and power transfer locates on the contour of the 3D region's boundary.