Date Added: Aug 2009
Energy efficient communications in wireless communications is very important as mobile devices are battery-constrained. For mobile devices in a cellular system, uplink power consumption dominates the wireless power budget, due to the RF power requirements for reliable communications over long distances. Their previous work in this area demonstrated significant energy savings in uplink cellular OFDMA transmissions, with iterative approaches maximizing the instantaneous bits-per-Joule energy efficiency. In this paper, the authors use a time-averaged bits-per-Joule metric to develop low-complexity schemes. Specifically, they obtain closed-form solutions for energy-efficient link adaptation in frequency-selective channels. They also derive closed form approaches for the maximum arithmetic and geometric mean energy-efficient schedulers.