Spectrum Reorganization and Bundling for Power Efficient Mobile Networks

Technological improvements and evolving user requirements have led to operators running and supporting three distinct wireless access technologies, GSM, UMTS, and LTE. While the most recent layer (LTE) introduces improvements in spectral efficiency and peak data rates, the remaining layers are still required for supporting legacy devices and providing wider network coverage. In order to facilitate and reduce the cost of rolling out a new network, mobile operators often reuse existing sites. Radio frequency modules in base station sites house power amplifiers, which are designed to operate within a specific frequency band. Since some access technologies have spectrum split onto multiple bands, this results in operators installing multiple modules for each access technology. This paper quantifies the power savings that can be achieved by assuming that the available spectrum for an operator can be reorganized within a single band, and have multiple carriers bundled together to fully exploit the capabilities of modern equipment. These modifications are applied on all network layers, maintaining the same number of carriers and baseband capacity. For the presented case, this results in the elimination of at least four separate modules in each site, reducing the power consumption of by 31%. Indirectly, this also translates into a reduced site space of 40%. These savings are crucial for mobile network operators to reach the energy and carbon emission targets they have committed for.