Limitations of Experimental Channel Characterisation

Doctoral Thesis / Dissertation from the year 2008 in the subject Electrotechnology, grade: summa cum laude, Technical University of Ilmenau, language: English, abstract: This thesis deals with Experimental Channel Characterisation and its performance limits in real propagation environments. This includes recording of the multidimensional wideband channel matrix by using a MIMO channel sounder and antenna arrays at both sides of the link. High-resolution parameter estimation is finally applied to characterise the channel in terms of DoD, DoA, TDoA, and complex polarimetric path weights. The quality of these estimates in "real world" scenarios is degraded by several impairments of the practical antenna arrays and the measurement system used. The resulting estimation quality limits are investigated in detail by simulations and measurements. The entire processing chain is analysed in terms of possible error sources. To this end, measurement system impairments, antenna array calibration errors as well as limitations of the radio channel model comprising two parts: specular like reflections (SC) and distributed diffuse scattering (DMC) applied by the high-resolution parameter estimation procedure are investigated. Moreover, consequences of using these results to deduce and parameterise geometry based channel models are demonstrated. The contributions of this thesis are of interest for researchers dealing with high-resolution parameter estimation and channel modelling and can be summarised as follows: - the efficient and accurate radiation pattern modelling of antenna arrays, - the powerful performance evaluation framework for practical antenna arrays, - the exposure of consequence of modelling errors on parameter estimation, - and the demonstration of overall limitations of Experimental Channel Characterisation.