Energy Efficiency Evaluation in Downlink Cellular Communication Networks

This paper investigates schemes that maximize energy efficiency in cellular networks. We derived the energy efficiency function in terms of system bandwidth, transmission success rate, constellation size, signal-to-noise ratio (SNR) and transmission power. Numerical results indicate that, the transmission success rate function will grow exponentially for an increase in SNR. As a result, the energy efficiency increases linearly when the transmit power is considered constant; however, it increases logarithmically when the transmit power increase proportionally with the system bandwidth. In addition, we showed that the energy efficiency maximization is not necessarily related to rate maximization and use of all available power. With a constant transmit power; the energy efficiency can be increased by 9dB for higher channel gains. Furthermore, it is shown that the energy efficiency can be maximized with a simultaneous increase of both system bandwidth and constellation size without maximizing the transmit power.