Outage performance of cognitive DF relaying networks employing SWIPT

In this paper, the outage performance of a cognitive relaying network over Nakagami-m fading channels, employing simultaneous wireless information and power transfer (SWIPT) technology is analyzed and evaluated. The operation of this network is considered in conjunction with the conventional decode-and-forward (DF) and incremental DF (IDF) protocols. For the conventional DF protocol, it is assumed that there is no direct link between the secondary transmitter (S) and the secondary destination (D), while (for both protocols) after harvesting energy, the relay node (R) always helps to forward the resulting signal to D. However, for the IDF protocol, R assists in relaying S’s information to D only when the direct communication between S and D has failed. Furthermore, for both DF and IDF protocols, we assume there is no power supply for R, and R harvests energy from the transmitted signal of S. We derive exact analytical expressions for the outage probability at D in DF and IDF protocols, respectively, in terms of the bivariate Meijer’s G-function. Performance evaluation results obtained by means of Monte-Carlo simulations are also provided and have validated the correctness of the proposed analysis.