QoS driven energy-efficient design for downlink OFDMA networks

The ubiquitous applications of high-data-rate realtime wireless services have promptly boomed energy consumption in wireless networks. Therefore, energy-efficient design in wireless networks is very important and is attracting more and more research attention. In this paper, we study the quality-of-service (QoS) driven energy-efficient design in the downlink orthogonal frequency division multiple access (OFDMA) network. By integrating information theory with the concept of effective capacity, we formulate an energy efficiency (EE) optimization problem with statistical QoS provisioning. To solve the problem, we first modify it with a tight upper bound on the original EE and solve the modified problem. Then, we demonstrate that the resultant solution is quite close to the true optimal value when the number of subcarriers is large than that of the users. We also find out the tradeoff relation between EE and delay. Numerical results show that the proposed energy-efficient design scheme greatly improves EE whiling maintaining QoS requirements.