Green Dynamic Spectrum Aggregation – Green-Dyspan

The proliferation of wireless mobile networks and the ever-increasing density of wireless devices underscore the necessity for efficient allocation and sharing of the radio spectrum resource. Traditional wireless communication techniques support exclusively the utilization of continuous spectrum bands, which are rarely available today. In such context, spectrum aggregation has been recently proposed as a promising technique which combines both contiguous and non-contiguous spectrum fragments to create a virtual wideband channel for data transmission, thus significantly increasing the spectrum efficiency.

Despite its important research and application value, the research works on spectrum aggregation have just emerged with many important theoretical and technical problems waiting to be solved. Among the research challenges, energy efficiency is of crucial importance. Indeed, while spectrum efficiency is the primary concern of spectrum aggregation, there has been a paradigm shift towards reducing energy consumption due to the steadily rising energy cost and environmental concerns. Moreover, in practice, these are often conflicting objectives, as some energy efficiency criteria are opposed to spectrum efficiency objectives. Hence, there is an urgent need to jointly address spectrum and energy efficiencies, and to design spectrum aggregation mechanisms that achieve a desired balance.

The proposed Green-Dyspan project aims at developing the fundamental building blocks for green dynamic spectrum aggregation by addressing the following crucial research problems: (1) How to intelligently sense the spectrum channels to be aggregated so as to find the best ones, while limiting at the same time the energy cost related to the sensing operation? (2) How to aggregate efficiently non-contiguous spectrum channels, given their heterogamous nature, and how to avoid excessive channel switching which is energy consuming?

Specifically, the Green-Dyspan project will (1) develop a theoretical framework characterizing the tradeoff between spectrum and energy efficiencies in spectrum aggregation; (2) design green dynamic spectrum aggregation mechanisms that jointly optimize the spectrum sensing, spectrum aggregation and access so as to achieve a desired balance from both spectrum and energy perspectives; (3) implement the proposed mechanisms in real-life testbeds to capture the impact of physical and link-layer operations on the proposed solutions.

In this project, new mathematical models and tools will be developed based on decision theory, optimization and game theory, to provide a solid theoretical study. Advanced techniques in wireless communication and signal processing, as well as cross-layer design, will then be integrated with the theoretical results. Under such transversal research efforts, the developed spectrum aggregation mechanisms will significantly increase the spectrum and energy efficiencies by systematically taking into account the heterogeneous nature of aggregated spectrum bands, as well as the practical constraints due to physical and link layer limits.