Improved Hybrid Relaying Protocol for DF Relaying in the Presence of a Direct Link

摘要

This letter proposes an improved hybrid relaying (i-HRe) protocol for a decode-and-forward relay system in the presence of a direct link between the source and the destination. A non-linear energy harvester is equipped at the relay to facilitate simultaneous wireless information and power transfer. We formulate an optimization problem to maximize the system capacity by optimizing the parameters of the proposed i-HRe protocol, i.e., time-switching ratio and power-splitting ratio. As this problem is non-convex, we convert it into two subproblems by means of the inequality relation between the signal noise ratios of source-relay link and relay-destination link to derive the optimal solution. Simulation study verifies the fast convergence of the proposed iterative algorithm. The results show that the i-HRe protocol achieves a higher system capacity than the existing protocols.