Measurements of Shadow Correlations in a Suburban Environment on the 485 MHz Band

Correlations in shadow fading play a key role in the performance of wireless networks. However, despite of this importance, relatively few comprehensive measurement studies have been made on shadow correlations, and the methodology followed in the existing studies is often poorly documented. In this paper we report results from an extensive measurement campaign on shadow correlation in the 485 MHz band in a suburban environment. In particular, we study carefully the influence of fast fading and different data processing choices on the results, as well as describe in detail the design and verification of the measurement set up. Our results show that shadow correlations decay exponentially as a function of distance also on this band, but that the details of the arising correlation model are highly dependent on the steps taken to process the measurement data. In particular, we show that unless fast fading is properly averaged over, highly incorrect conclusions would be drawn with respect to both marginal variance and the correlation distance of shadow fading.