A Unified Energy Efficiency and Spectral Efficiency Tradeoff Metric in Wireless Networks

In this letter, we propose a unified metric for energy efficiency (EE) and spectral efficiency (SE) tradeoff design in wireless networks. Different from previous EE-based or SE-based design, we simultaneously optimize both EE and SE. First, we formulate our design problem as a multi-object optimization (MOO) problem, in which the Pareto optimal set is characterized. After normalizing EE and SE to make them comparable, we then convert the MOO problem into a single-object optimization (SOO) problem by the weighted product scalarization method. We further show that the objective function of this SOO problem, i.e., our proposed EE and SE tradeoff (EST) metric, is quasi-concave with the transmit power and a unique globally optimal solution is derived. Numerical results validate the effectiveness of the proposed unified EST metric.