Intra-operator dynamic spectrum management for energy efficiency

Spectrum usage in wireless communications has traditionally been very conservative, with each spectrum band at a particular location being constrained to a single owner and usage purpose. Recent developments are, however, pointing toward the freer use of spectrum by a range of users and purposes, providing that those users/purposes agree and that various constraints are maintained. This article investigates dynamic spectrum access by an operator of its range of available spectrum bands as a means to improve power efficiency. The concept is based around three areas of interest: (1) Moving users into particularly active bands to allow radio network equipment in the bands they originated from to be switched off when possible. (2) Dynamic resource allocation in order to opportunistically take advantage of spectrum of more appropriate propagation and reduce necessary transmission power. (3) And dynamic resource allocation to allow channel bandwidths given to users to be increased or more appropriately balanced, thus facilitating transmission power being significantly decreased. Example results are presented, which show a potential for such spectrum management solutions to greatly reduce power consumption by some 50 percent or more, either from-the-mains (i.e. "guaranteed" power saving), or more generally in terms of necessary transmission power. It is noted that although the main objective of this article is energy saving, the concepts presented might also be used for other purposes, such as to increase achievable capacity for the operator.