On the Requirements of Secondary Access to 960-1215 MHz Aeronautical Spectrum

In this paper, we investigate the spectrum sharing requirements of secondary access to 960-1215 MHz band which is primarily allocated to aeronautical usage. Primary system of interest is distance measuring equipments (DME) aiding navigation of airplanes. We consider a scenario where indoor femtocells share the spectrum as secondary users. For the protection of the primary system, each secondary user decides whether to transmit or not depending on an interference threshold established by a central network. We provide a simple mathematical framework for analyzing the aggregate interference generated by multiple secondary users spreading in a large area. Requirement for the secondary access is established in terms of the size of exclusion region depending on the density of secondary users. Numerical results suggest the use of adjacent DME channel is required for a dense deployment of the secondary users. We discuss the challenges and implementation issues of practical secondary access, and suggest the directions of further research.