Geolocation databases for white space devices in the UHF TV bands: Specification of maximum permitted emission levels

In this paper we present the detailed calculations which a geolocation database would need to perform in order to derive location-specific maximum permitted emission levels for white space devices (WSDs) operating in digital terrestrial TV (DTT) bands. We introduce a novel methodology for the calculation of such emission levels, whereby the extent of protection afforded to the DTT service is specified in terms of a maximum permitted degradation in the DTT service location probability. We illustrate how national DTT network planning models can be used to provide the necessary parameters for a geolocation database to perform the necessary calculations. We explain how the calculated emission levels need to be post-processed in order to derive consistent WSD regulatory emission limits for the simultaneous protection of multiple DTT channels. We finally use numerical examples to show that the resulting WSD regulatory emission limits can be quite high in areas where the DTT coverage quality is good and the DTT service is therefore relatively immune to interference from WSDs.