Spatial and temporal distribution of the VHF/UHF radio waves in built-up land communication links

We present a unified approach of the description of the spatial and temporal distribution of radio signals within built-up radio communication links. This approach is based on a multiparametric stochastic model, which takes into account the characteristic features of built-up terrain and peculiarities of radio wave propagation related with multiple reflections, diffraction and scattering phenomena caused by obstructions surrounding both terminal antennas, the receiver and the transmitter. To describe fast fading phenomena, we propose a new general distribution of signal strength fast fading, which successfully covers the Ricean distribution in line-of-sight (LOS) and quasi-LOS conditions and the Rayleigh distribution in no line-of-sight multipath conditions usually used for description of land communication links. This new distribution leads to a multiparametric stochastic model. Based on this model, we present a strict estimation of scales of slow and fast fading and present the corresponding correlation functions in space and time domains, which describe slow and fast signal fluctuations. Finally, the power distribution in the angle-of-arrival (azimuth) domain, following the proposed stochastic approach, is considered and analyzed, both for uplink and downlink mobile communication channels