Cognitive Spectrum Management in TV White Space: Libya as a Case Study

Abstract

The traditional spectrum allocation scheme is based on static allotment of frequency bands to applications and entities in specific geographical areas for extended periods of time. Telecommunications regulations, on the national and international levels, are established to protect these primary users from any interference and guarantee exclusive access to allocated spectrum. Such exclusive access model results in very low spectrum utilization while new applications are prevented from accessing the spectrum thus creating a spectrum scarcity problem. Dynamic Spectrum Access (DSA) aims to solve this problem by allowing secondary users to opportunistically access the spectrum through Cognitive Radios (CRs) that can sense the spectrum and avoid interfering with the primary holders of the spectrum access rights. Regulatory bodies around the world are taking rapid steps towards realizing DSA and setting the rules for shared spectrum access.

TV White Space (TVWS) is the prime contender for spectrum sharing with standards now being developed allowing dynamic spectrum access of the unused TV spectrum for secondary applications through centralized Geo-location database. The Geo-location database framework is aimed at ensuring coexistence of secondary users with primary TV broadcasters and protecting the TV broadcasters and other incumbents like wireless microphone systems from harmful interference secondary users may cause. However, a comprehensive model for spectrum sharing that incorporates regulatory, application, and economical requirements into the spectrum management process and addresses secondary-to-secondary users' coexistence in conjunction with primary-to-secondary users' coexistence is yet to be proposed.

This work addresses this need by presenting a combined design and implementation of a Cognitive Spectrum Management System (CSMS) incorporating a Cognitive Framework for spectrum management in TV White Space. The system ensures both primary-to-secondary and secondary-to-secondary users' coexistence via a Geo-location Database System and a Spectrum Manager that allocates spectrum to competing secondary users while maximizing total spectrum allocation. A system implementation is conducted for the case of Libya were TV broadcasting stations' information is collected from regulatory sources and TVWS availability is estimated for parts of the country.