# A Novel Power-Saving Transmission Scheme for Multiple-Component-Carrier Cellular Systems
## 2 Related Work  
A substantial amount of the past research regarding designs for radio resource allocation in cellular systems has been concentrated on systems utilizing multi-user single-CC BSs, with several studies having given particular attention to various methods used to improve system performance from the standpoint of individual contributions [9; 10; 11; 12; 13; 14; 15; 16; 17; 18]. More specifically, [PERSON] _et al._[9] proposed a jointly adaptive bit, subcarrier, and power allocation algorithm as a means of improving the performance of a system. In contrast, in the study by [PERSON] _et al._[10], the authors proposed a scheme involving high efficiency cross-layer packet scheduling and resource management. In yet another approach, [PERSON] _et al._ detailed a set of algorithms relying on greater computational efficiency in determining the allocation of power and subcarriers among system users [11], whereas [PERSON] _et al._ proposed fast algorithms to handle the task of ensuring resource allocation optimization in order to maximize the overall utility of a system [12]. In another study, the subject of how to allocate resources for energy-efficient communication in the context of single-cell downlink environments with numerous transmitting antennas was addressed by [PERSON] _et al._[13]. Subsequently, the same researchers extended their research framework further to include multi-cell downlink environmentswith cooperative BSs [14]. Meanwhile, a study by [PERSON] _et al._ focused on the physical-layer aspect in its investigation of energy-efficient coordinated beamforming and power allocation in multi-cell downlink environments [15]. In a still more recent study, [PERSON] _et al._ proposed an optimization framework aimed at minimizing the degree of power consumption while also providing the minimum bit rate required for each mobile terminal [16]. Still another approach utilized the development of heterogeneous network deployments with macrocells and small cells in order to enhance energy efficiency [17; 18]. Nevertheless, although each of these studies (_i.e._, [9; 10; 11; 12; 13; 14; 15; 16; 17; 18]) made some important contributions, none of them looked explicitly at multi-CC BSs or the important subject of energy savings. As such, their contributions, while valuable, do not have much direct relevance to the growing concerns regarding energy consumption and associated CO\({}_{2}\) emissions discussed in the introduction above. Nonetheless, as regulatory agencies and people in general have become increasingly aware of the environmental problems linked to energy usage, the subject of green communication technologies, including green cellular systems, has become the focus of a major trend in communications research [3; 4; 5; 6; 7; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28]. Several important studies [3; 4; 5; 6; 7], for example, have sought to provide overviews of the various issues related to energy consumption in communication networks. In terms of directly practical research, meanwhile, [PERSON] _et al._[19] authored a study proposing a cell-zooming-based energy-saving algorithm aimed at providing dynamic adjustments to the transmission power of BSs, while the energy-saving management group of the 3 rd Generation Partnership Project (3 GPP) presented a number of network architectures aimed at providing energy savings on a system-wide basis [20]. [PERSON] _et al._[21], meanwhile, proposed an energy-saving algorithm aimed at exploiting variations in network traffic levels in the context of dual-cell high speed downlink packet access systems. Relatedly, [PERSON] _et al._ looked at methods for managing the levels of power used by network devices in the context of realistic traffic patterns as a means of minimizing the overall amount of energy consumed by wireless access networks [22], while [PERSON] and [PERSON] proposed a model aimed at optimizing both CC activation/deactivation and radio resource allocation in order to save power during BS transmissions [23].