Field measurements of WSD-DTT protection ratios over outdoor and indoor reference geometries

A currently prevalent view of the operation of white space cognitive radios is that they should use geolocation databases to determine their frequency band and maximum transmission power in any given location so that interference radiated to broadcast receivers is negligible. To estimate the level of such interference, physical reference geometries and path loss estimates have been proposed between co-located devices. In this paper we present results of a measurement campaign conducted over indoor and outdoor reference geometry scenarios in a digital terrestrial television test network. Applying a subjective error criterion, we provide practical estimates on the maximum relative transmit powers for white space devices in order to avoid visible interference in television reception. The study applies to various primary and secondary transmission and reception scenarios, and its results can be extended also to estimate protection ratios for signal configurations not considered in the reported measurements.