Fine Resolution Simulation of TV White Space Availability and Model Validation

Abstract

Availability of television white space is of interest for developing new data networks which operate between licensed users. The practical sensing and computational modelling of this band has been the focus of study in this and a preceding paper [1]. In this paper a high spatial resolution was used to look at the areas that a single channel was available in moderately rough terrain in the UK. The size of areas which shared available frequencies was found to be small and potential problems with spot measurements were highlighted. The practical validation of the software model with a measurement campaign has been started, the early results of this show the model to be reasonably accurate in exposed areas with little building but at portable equipment heights in streets the model shows significant variation from measured results.

Propagation modelling for white space geo-location databases

“…The revised code for modelling white space availability works on the same principal as previous versions [2], [4] but has been sped up and run at a much finer resolution. Additional calculation has been added to improve the estimation of power per unit bandwidth which will be shown to more accurately match field trial results and improves the availability predictions significantly.…”

“…The size of available areas of white space was found to be small though, suggesting that large scale protocols, such as 802.22 would be less well suited than the 802.11af standard. In a following paper [4] a higher resolution simulation was carried out over a small area and the size of available white space areas was confirmed to be small and scattered. In this second publication the validity of the model was also tested against a set of field trials to see how accurately the model predicted real signal strengths.…”

“…Field measurements were carried out using a USRP N210 and custom software as described in [4]. The internal low noise amplifiers of the WBX receiver board were used this time and set at 20 dB to improve the signal to noise ratio.…”