Outage Probability Analysis of DF Relay Networks with RF Energy Harvesting

In this paper, we analyze the outage probability of a three-node decode-and-forward (DF) relay network, where the relay adopts a power-splitting protocol to harvest energy from the received signal, and utilizes the harvested energy to forward information. First of all, the theoretical expression of outage probability is derived, and then the closed forms of the optimal amount of harvested energy and the best relay location are achieved analytically in order to minimize the outage probability. Furthermore, the condition that the outage performance with energy harvesting (EH) surpasses that without EH is also deduced to figure out when EH is indispensable to relay enhancements. Numerical results verify the correctness of our theoretical derivation, and validate that there exist the optimal amount of harvested energy and the best relay location to reach the minimum outage probability in the energy harvesting relay network. The work of this paper will provide valuable insights into the effect of harvested energy and relay location on outage probability, and be instrumental in how to deploy relays with RF energy harvesting functions.