Wide Area Adaptive Spectrum Applications

This paper examines spectrum opportunistic systems in which the currently assigned spectrum is monitored in real time for idle bands, specific waveform types are dynamically created to utilize the idle portions of spectrum, and those portions of the spectrum are used until the primary user needs them. This application operates over significantly expanded geographic areas without the typical structure encountered in today's cellular/Personal-Communication-System (PCS) applications. Current spectrum policy may not yet support this type of operation in the frequency bands required for the expanded coverage. However, the approach has potential for enhanced spectrum reuse together with applications for emergency and transient scenarios in which spectrum coordination may be difficult to obtain within the operational time limits. The focus of this paper is to examine the technical performance achievable by non-overlaid, loosely structured architectures that employ multi-carrier implementations to dynamically adapt to a changing spectrum environment without predefined channel structures. For the case of assigned but unused spectrum, this architecture extends to continuous use applications representative of classical reuse scenarios.