Interference aided energy harvesting in decode-and-forward relaying systems

Wireless energy harvesting is an effective way to prolong the lifetime of wireless networks. In this paper, a novel interference aided energy harvesting scheme is proposed for decode-and-forward relaying systems. In this scheme, the energy-constrained relays harvest energy from the received information signal and co-channel interference (CCI) signals and then use that harvested energy to decode the source signal and forward it to the destination node. A time switching scheme, in which the receiver switches over time between decoding information and harvesting energy, is adopted due to its circuit simplicity and availability. Applying the proposed interference aided energy harvesting approach to a decode-and-forward relaying system with the three-terminal model, the analytical expression of the ergodic capacity is derived in order to determine the achievable throughput at the destination node. Furthermore, the optimal value of the energy harvesting ratio, which maximizes the throughput of the system, is investigated. The CCI signals can provide energy for relay recharging and hence effectively reduce the optimal value of the energy harvesting ratio. Furthermore, by lowering the noise variance or applying some interference cancellation schemes at the information decoder, the utilization of the CCI signals can be enhanced to improve the system performance further.