Simplifying the propagation environment representation for LMS channel modelling

Mehdi Ait-Ighil,Fernando Pérez-Fontán,Christophe Bourga,Michel Bousquet,Frederic Lacoste,Joel Lemorton,Geraldine Artaud

doi:10.1186/1687-1499-2012-110

Abstract

A deep knowledge of all propagation effects has become an essential issue to design future communication and navigation systems and optimise their performances. Here, we will target Land Mobile Satellite (LMS) systems, with focus on Global Navigation Satellite Systems (GNSS). The urban environment is one of the most critical for LMS systems, since shadowing, multipath fading and time spreading are often present. This study aims at developing more efficient propagation channel models using physical-statistical approaches. In order to build these models, numerical asymptotic tools are to be used to avoid costly extensive measurements. These tools are theoretically valid for large objects. So, it is necessary to know which level of simplification of the environment is acceptable. Thus, this article performs a rigorous analysis of the influence of small scatterers at different levels of the transmission channel (up to the GNSS receiver), using the exact Method of Moments technique as a reference.

Highlights

Over the past decades, mobile applications using satellites have experienced a continuous growth and the demand for such systems does not fall off
The above systems are operating at L- and Sbands and are sensitive to various channel impairments induced by urban environments, namely shadowing, multipath fading, delayed echoes, Doppler spreading, depolarisation, etc
The future channel simulator shall be able to generate synthetic time-series for simulation needs with a specific attention on the wideband representation of the channel for Global Navigation Satellite Systems (GNSS) studies

Summary

Introduction

Mobile applications using satellites have experienced a continuous growth and the demand for such systems does not fall off. This study is part of a wider project aiming at reproducing channel impairments in order to build an enhanced Land Mobile Satellite (LMS) channel simulator. The future channel simulator shall be able to generate synthetic time-series for simulation needs with a specific attention on the wideband representation of the channel for Global Navigation Satellite Systems (GNSS) studies. A hybrid approach associating a virtual city [1] Due to this limitation, interactions between a complex environment with small features and EM waves cannot rigorously be modelled. Urban scenarios were addressed and especially building scattering where numerous small features are present. It completes preliminary results presented in [3] and is mainly focusing on GNSS context.

Proposed approach

Findings

Conclusion