An efficient power-saving downlink transmission scheme in OFDM-based multiple component carrier systems

Traditional resource allocation studies of wireless access networks almost all focused on the maximization of the network capacity and quality of services (QoS). As the development of the cellular technologies (such as LTE-Advanced) progress, more than one component carrier (CCs) can now be jointly utilized in a base station (BS). However, the use of some CCs may not be necessary at light traffic loads, from the point of view of green communication. In this study, we propose a technique for dynamic power adjustment to enable energy-efficient data transmissions. That is, utilize only the necessary transmission power. In our model, the activities in downlink transmissions of a BS with 2 OFDM-based CCs are considered, while simultaneously supporting both real-time and non-real-time users. We employ a computationally efficient scheme according to the fluctuating traffic load to address the problem of power minimization at the BS transceiver, subject to the constraint of minimum rates for all users. Simulation results demonstrate that the energy consumption of our proposed scheme is much better than that of the case in which all CCs are always active, when both schemes maintain the required QoS.