Maximizing energy-efficiency in multi-relay OFDMA cellular networks

Abstract

This contribution presents a method of obtaining the optimal power and\nsubcarrier allocations that maximize the energy-efficiency (EE) of a\nmulti-user, multi-relay, orthogonal frequency division multiple access (OFDMA)\ncellular network. Initially, the objective function (OF) is formulated as the\nratio of the spectral-efficiency (SE) over the power consumption of the\nnetwork. This OF is shown to be quasi-concave, thus Dinkelbach's method can be\nemployed for solving it as a series of parameterized concave problems. We\ncharacterize the performance of the aforementioned method by comparing the\noptimal solutions obtained to those found using an exhaustive search.\nAdditionally, we explore the relationship between the achievable SE and EE in\nthe cellular network upon increasing the number of active users. In general,\nincreasing the number of users supported by the system benefits both the SE and\nEE, and higher SE values may be obtained at the cost of EE, when an increased\npower may be allocated.\n