Circuit Power Considered Energy Efficiency In Decode-and-Forward Relaying

In this paper we analyze Energy Efficiency (EE) and Spectral Efficiency (SE) in relay based systems. Our system model is based on two data transmitters as sources and one relaynode with Decode-and-Forward (DF) scheme. The system can work in two strategies, DF relaying and direct transmission. Inaddition to transmission power we consider circuit power of nodes in our Power Consumption Model (PCM) and find the best EE-SE for each strategy by optimizing transmission time and power of each node. Simulation results show that SE-EE trade off in DF relaying has better performance than directtransmission. Despite traditional research that shows exponential decreasing of EE with increase in SE, we will showby considering circuit power, EE-SE relation has a cup shape. The best EE will be achieved by optimizing power and time duration of transmission.