bstructed Line-of-Sight the modelled delay spread falls with distance. (OLoS) and NLoS links, but are coupled for LoS. For LoS, the intracluster marginal power density distributions showed exponential decay with excess delay and were Intracluster dispersion Laplacian for the azimuthal power density, Figure 4.7-41. The concept of clusters of scatterers has been brought An alternative method by Czink and Yin uses into radio channel modelling, both to ease and to refine a Bartlett beamformer to coarsely determine clusters in the statistical description of mobile channel behaviour the AoA-AoD domain. SAGE estimates of corresponding The scattering environment is in this concept seen as AoAs and AoDs derived from instantaneous channel consisting of a distributed set of concentrations of scat- realisations were then selected with this cluster in- terers, the clusters. Description of the properties of these formation [CzYi05]. From the clustered estimates, an- clusters of scattering objects was undertaken by a number gular spreads were calculated. On synthetic data, spread of groups within COST 273. Chong et al. took mea- estimates were shown to be approximately unbiased. The surements at 5.2 GHz with 120 MHz bandwidth in a large authors observe on measured data different intracluster office and a large open space, during office hours angular spreads at the TX and RX side [CBYF05], likely [CTLM02]. An FD-SAGE for estimation of multipath due to the position of the TX antenna in the corridor, components was used and the delay-azimuth estimates Figure 4.7-42. This method is an improvement of an AoA RMS angular spread (°) AoA RMS angular spread (°) (a) AoA RMS angular spread. (b) AoD RMS angular spread. Figure 4.7-42 Histograms of cluster angular spread estimates for measured indoor data (after [CBYF05]). CHAPTER 4.7 Propagation modelling and channel characterisation Table 4.7-14 UWB cluster properties in residential environment (after [HaTK05]). Scenario No. clusters No. paths/ cluster Delay spread [ns] Angular spread [°] F