Energy Efficiency of The Cooperative Communication Systems With Energy Harvested at Source and Relay Using Battery Power at Relay

The effects of the energy harvested (EH) technology and battery power at relay which are used together in a cooperative communication system with amplify and forward (AF) relaying protocol are investigated in this work. The Time Switching based Relaying (TSR) protocol is used for harvesting energy process at source and at relay nodes. Also the opportunistic relay selection strategy is used to select a best relay among three relay nodes. From the simulation results, it can be shown that the high time switching factor (ρ) of TSR protocol, the low battery transmit power of access point at relay (PAp), and the low noise gain (N0) will result the good EE performance. At a distance of 160 meters, each addition of 0.05 ρ has an effect on increasing the EE performance of the system by about 0.88%; beside that, if PAp value is reduced by 0.01 watts, the EE performance will increase by about 2.46%; also, each 10 dBm N0 reduction will give up to 11.8% better EE performance.