Optimal Power Splitting and Censoring Strategies for SWIPT-Enabled DF Relay Systems with Relay Censoring

Abstract

In this paper, we study wireless energy transfer (WET) and analyze error performance in a cooperative decode-and-forward (DF) relaying network with a source node, a censoring DF relay, and a destination node with simultaneous wireless information and power transfer (SWIPT) capability implemented by power splitting (PS). With relay censoring, the relay assists the source (S) to transmit information to the destination (D) only when the signal-to-noise ratio (SNR) exceeds a carefully designed threshold, which prevents error propagations in a DF relaying system. However, the amount of energy the destination node can harvest is thus limited, as the relay is not always forwarding signals with relay censoring. On the other hand, setting a lower SNR threshold allows for more energy to be transferred to the destination at the cost of degraded error probability due to error propagations. There exists a tradeoff between WET and the error performance in the system. We analytically derive the SNR threshold and numerically obtain the PS ratio that minimizes the overall system error probability with a harvested energy constraint.