Author(s): K.Venkata Ramana, Narmala Raju

This letter investigates the tradeoff between energy efficiency (EE) and spectral efficiency (SE) in downlink multiuser OFDM using load matrix concept. Given the SE requirement and maximum power limit, a constrained optimization problem is formulated to maximize EE. Because of the multi-dimensional and non-convex nature of the problem, we first transform the multicriteria optimization problem with high complexity into a simpler single objective optimization problem. Then a novel power allocation algorithm is proposed to achieve maximum EE. Simulation results demonstrate the effectiveness of the proposed scheme as well as illustrate the fundamental tradeoff between energy efficient and spectral efficient transmission in downlink multiuser OFDM.