Secrecy outage of a multi‐relay cooperative communication network with accumulation of harvesting energy at relays

Security of confidential data at the physical layer has been analysed in a network where the source sends the confidential data to the destination via multiple energy harvesting decode and forward relays in the presence of a single eavesdropper (EAV). In this two-hop communication, the first hop is broadcasting hop when the source sends the information signal to relay and other is the relaying hop when a selected relay forwards the information signal as well as transmits a jamming signal to destination and EAV. Each relay has the two batteries; one for accumulating the harvested energy and the other for power supply to relays for relay operation over a number of frames until the accumulated harvested energy becomes sufficient. In the broadcasting hop, relays harvest energy using a power splitting ratio scheme and accumulate the harvested energy in the battery over a number of communication frames. The performance is analysed in the form of secrecy outage probability (SOP) when the relay uses only the harvested energy to forward the signal. A closed-form analytical expression for the SOP is derived. MATLAB-based simulation results match well with the analytical results.