Supportive relay with heterogeneous transceivers: Quantification of energy efficiency improvement

Energy consumption of two-hop transmission via supportive relay is derived and compared with energy consumption of the direct link between the same source and destination. First, a model of total transceiver power consumption as a function of transmit power is reviewed. Assuming adaptive transmission power control with perfect knowledge of channel loss, the total transceiver power consumption becomes a function of the channel loss. We derive the ratio between two-hop and single-hop energy consumption as a function of channel loss along each of the three links. The equipotential planes of this ratio are compared with the operating region of the transceivers, in the space of channel losses. We show how the transceiver parameters influence energy efficiency of two-hop supportive relay, relative to the direct link, and apply the analysis to the cellular scenario with one relay between the base station and a user terminal.