Energy Efficiency Analysis in DecodeandForward Cooperative Networks

With the increasing awareness of resource conservation and environmental protection, how to obtain higher energy efficiency (EE) has become an important and difficult issue in the green communication field. Therefore, the EE of direct transmission, oneway relay transmission and twoway relay transmission under the decodeandforward protocol is studied in this paper. Firstly, the close form of EE in the Rayleigh fading channel is derived, and then the EE is maximized by using the convex optimization algorithm. Finally, the impacts of the fading channel condition, the transmitted bit numbers, the relay position and the circuit power consumption on EE are also analyzed. Simulation results show that circuit power consumption has a great influence on EE, and the EE of twoway relay transmission is optimum when the bidirectional data amounts and the distance from source nodes to the relay are symmetric. However, oneway relay transmission is better than twoway relay transmission when the distance from source nodes to the relay are asymmetric. Moreover, twoway relay transmission has more advantage than oneway relay transmission and direct transmission when the channel fading is serious.