Motivation for the project: Mobile data traffic is growing fast and local area off-loading is required. Femtocells have from the mobile communications industry been the envisioned solutions for local area traffic off-loading. Current femtocell solutions do not scale to very dense deployment. Spectrum availability is a critical issue while the license conditions of the wired subscriber lines lead to “closed subscriber groups”. On the other hand, WiFi is the current de facto standard for wireless local area communication, but it is operating in a general-purpose unlicensed band and spectral efficiency and link quality tend to break down in very dense deployment scenarios. There is a clear need for creating “beyond-femtocells”.
The hypothesis of the project is that cognitive femtocells in a license-exempt band, along with an optimized spectrum policy, provide an efficient long-term solution to support the fast growth in mobile data traffic.
This project has two main success criteria:
• To demonstrate how the Cognitive Radio concept can be used to significantly improve the spectrum utilization and link performance compared to the current WiFi and femtocell solutions.
• To impact future standardization and spectrum policies for cognitive femtocells. It is envisioned that the results shall impact standardization and spectrum regulators for reservation of a license-exempt band of 100MHz or more in the 3.4-3.8GHz IMT band.
Core research concepts: The project has two main core research steps that converge in a unified vision on spectrum usage. The first core consists in the design and development, based on realistic transceiver models, of cognitive algorithms and protocols for improving the spectrum utilization of “beyond-femtocells”. The second is intended as a hardware demonstration of the developed concepts, in order to effectively prove their feasibility in practice rather than only in theory.