On the Energy Efficiency of MIMO Channels in Correlated Rayleigh Fading Environment

This paper investigates the energy efficiency (EE) performance for multiple-input multiple-output (MIMO) systems in correlated Rayleigh fading environment. Taking into account a realistic power model, we derive a closed-form upper bound for the system EE as a function of SE, which shows a good accuracy for a wide range of SE values, in the presence of spatial fading correlation at both the transmitter and the receiver sides. The upper bound helps the system explicitly track the influence of SE on EE and the effects of spatial correlation. Results demonstrate that given a fixed number of transmit and receive antennas, there exists a certain region of SE that corresponds to better EE performance. Results also indicate that when the circuit power dominates EE, EE is more tolerant to the spatial fading correlation; in contrast, when the transmit power becomes more dominant, EE is more sensitive to the changes of correlation coefficient.