Analysis of spectral efficiency and energy efficiency interrelationship in cellular networks with outage constraint

This paper analyzes the interrelationship between the spectral efficiency (SE) and energy efficiency (EE) of cellular networks where the base stations (BSs) are arbitrarily distributed. The SE and EE performance metrics are assessed subject to a downlink transmission outage constraint when operating in interference limited operational environments. The network EE is expressed in closed-form as a function of SE, based on which the performance bounds of the network are determined. It is found that there exists an operating regime for which both SE and EE can be increased up to the optimal density of BSs concurrently utilizing the shared spectrum while satisfying the outage constraint. The SE-EE tradeoff regime is found to be applicable only when certain conditions related to the outage objective and the BS density are satisfied. Furthermore, for a given outage constraint it is shown numerically that, by carefully tuning the signal to interference ratio (SIR) threshold, it is possible to balance and improve both SE and EE performance.