WLCp2-06: Modelling the Likelihood of Line-of-Sight for Air-to-Ground Radio Propagation in Urban Environments

Abstract

The likelihood of line-of-sight (LoS) is an essential component in any radio channel model. It is particularly useful for radio network planning and urban coverage prediction. Empirical LoS models are hard to derive due to a strong dependency on local topology and the need for large measurement datasets. Since buildings are the major obstructions in a dense urban environment, we propose a new theoretical model to determine the LoS probability for air-toground channels based on local building geometry and knife-edge diffraction theory. The model takes into account key statistical parameters such as building height, building size, building coverage, street width and street angle distribution. The theoretical model is shown to agree well with ray tracing simulation results. The statistical parameters, such as mean building height, percentage of area covered by buildings (building coverage) and building density, can all be easily obtained for a specific location. We also derive equations for the likelihood of LoS for a direct slant path. These equations can be used in the analysis of air-to-ground channels.

Enhancing Coverage and Reducing Power Consumption in Peer-to-Peer Networks Through Airborne Relaying

“…This research makes use of conventional and recently proposed channel models [3][4] [6]. To make a fair comparison between P2P and A2G channels, the value of each parameter in the models is derived for the same operating environment, a central area (around 1km×1km in size) of the City of Bristol.…”

“…However, in practice σ is a distance-dependent, or elevation-angle-dependent, variable. This paper uses the models proposed in [3][4] and [6] for the air-to-ground channels and the P2P channels respectively.…”

“…In [3], a theoretical model was proposed to estimate the probability of the combined LoS/OLoS propagation, i.e. free of building blockages.…”

“…However, for A2G channels, LoS propagation often dominates at high elevation angles from the mobile, and is also significant at low elevation angles [3]. A comprehensive study must take into account all channel types.…”

“…The major advantage of A2G channels is that they tend to encounter much less severe fading and shadowing compared to P2P ground channels. LoS propagation is often dominant for A2G channels [3]. Even when the channel type is NLoS, an A2G channel will tend to suffer from less pathloss and shadowing variation [4].…”