Spectral occupation of TV broadcast bands: Measurement and analysis

The findings of a TV broadcast spectrum measurement campaign, performed at six different locations on the Hatfield campus of the University of Pretoria, are presented. Since the use of television white spaces (TVWS) could help to alleviate the impending spectrum crunch, the motivation for the study was to identify possibly unused bands for use by emerging technologies, such as cognitive radio, and also to address the hidden node problem associated with spectrum sensing (SS). This was achieved by comparing measured data to both actual TV channel allocations and a geo-location database (GLDB) for the Tshwane metropolitan area (city of Pretoria). Localised measurements indicated that a number of TVWS opportunities existed, with between 216 and 376 MHz of spectrum found to be potentially available for secondary usage. However, a comparison with TV channel allocations (256 MHz free) and the GLDB (96 MHz free) highlighted the effect of the hidden node problem.