02]. Both the CRLB minimisation step next step in the development of RIMAX is proposed in and the beamformer optimisation step should be com- [RiEK05]. A state-space-based method, describing the bined to achieve satisfying results using the designed dynamics of the channel parameters in the time, for pa- antennas in channel measurements and analysis. rameter tracking in order to estimate the propagation paths is suggested here. This results in a lower computa- tional complexity and allows the tracking of the desired CRLB minimisation step time varying parameters as well. The performance of the One approach for the optimisation of antenna arrays used proposed technique is investigated using channel sounding in mobile radio channel characterisation devices is to apply measurements. a GA [KaKC02]. It is proposed to design the array of a channel characterisation system, in order to minimise the CRLB (minimum variance) of the DoA estimates. 4.7.4.4 Device performance and A critical issue is to choose the optimal array geometry, reliability of channel structure estimates namely to find the positions where the array elements should be placed, in order to obtain measurements that A thorough investigation of the multidimensional wave reduce the DoA estimation error to a minimum, assuming propagation mechanisms is a prerequisite for un- a minimum variance unbiased estimation algorithm, e.g. derstanding the spatial and temporal structure of the ML algorithm. Each sensor is supposed to have an iso- channel transfer matrix. The accuracy and reliability of the tropic beam pattern. It is shown that the GA determines CHAPTER 4.7 Propagation modelling and channel characterisation Figure 4.7-29 Polarimetric beam pattern for vertical (V) and horizontal (H) excitation (left) and corresponding EADF (right) for the vertical excitation (VV) of an SPUCPA. the position of the sensors to minimise the mean CRLB of elevation. Due to the periodicity of the beam patterns in the DoAs for unknown number and position of scatterers 2 the DFT tran