Special topics in wideband mobile radio channel modelling and measurements

Abstract

Synthetic models of the wideband mobile radio channel are required for mobile radio system design and optimisation based on simulations and for the implementation into hardware channel simulators for experimental investigations. These models correspond to a time varying transversal filter structure. For the derivation of such models from a set of wideband measured complex impulse responses a mathematical approach is presented. Each tap is described by its complex time-varying amplitude including its statistic and Doppler spectrum. Additionally long-term fading due to shadowing and distance dependence are taken into account This procedure has been applied to the derivation of wideband channel models based on extensive propagation measurement campaigns within the RACE-II Project 2084 ATDMA to be presented by the ACTS Project FRAMES AC090 to ETSI SMG5 and ITU TG8/1. These models have been accepted by ETSI SMG5 and partly by ITU TG8/1. Beyond the measurement campaigns within the ATDMA project, wideband propagation measurements and data evaluations for the directions-of-arrival at the base station have been performed. A method for wideband measurements and for postprocessing of these radio channel impulse responses which include directions-of-arrival information in the azimuth is introduced. Based on this method, measurement results for outdoor macrocellular environments are presented. Such results are essential for assessing, developing, evaluating and optimising adaptive directional antenna concepts and for extending wideband channel models including the directions-of-arrival. (7 pages)