By Marcus C. Walden
Abstract: This paper presents the results of a significant number of propagation measurements performed at 3.5 GHz in urban environments. Furthermore, the data collected is used to derive a statistical path loss model over the range 100 m to 2 km. This work offers valuable propagation measurements in a frequency range that is globally being allocated for broadband wireless systems.
Introduction- Over the period from December 2003 to June 2004, a large number of propagation surveys were conducted by Plextek and LCC UK on behalf of a client operating a radio network at 3.5 GHz. Measurements were performed in urban environments within major cities of the United Kingdom (London, Birmingham, Liverpool and Manchester amongst others). Although numerous path loss models are available (including the Hata  and COST 231 Walfisch-Ikegami  models) that describe propagation in urban, suburban or rural environments, they tend to be limited to the lower frequency bands (up to 2 GHz) and to large ranges (1–20 km) in the case of the Hata model. This provided the motivation to use the measured path loss data at 3.5 GHz to derive a log-normal shadow fading model appropriate for the actual measurement environment. This was found to agree very well with published work at other frequencies .