Background Information

Current static frequency allocation policies followed by government agencies responsible for regulating telecommunications have shown to be ineffective, which have resulted into 'artificial spectrum scarcity' in many countries. Spectrum measurements from several countries done in the licensed frequency bands have shown that they are unused most of the time. Therefore, new ways of sharing the unused channel in the licensed frequency bands are being investigated. The unused channels in the licensed television radio frequency bands are what are called television white spaces.


Several countries have now changed their communications regulations to permits unlicensed devices to transmit in TVWSs as long as they do not interfere with the primary licensed users of this spectrum. Two approaches have been proposed to achieve the smooth operation of both spectrum incumbents and unlicensed users in the TVWSs; use of a geo-location database and spectrum sensing. Geo-location database is the preferred method of choice in the developed world as it guarantees maximum protection of the spectrum incumbents. This approach may not necessarily be the method of choice for African countries and other developing countries where there are many TVWSs and access to the geo-location database may be a challenge. Therefore, spectrum sensing may be an alternative approach.