On the tap and cluster angular spreads of indoor WLAN channels

Herein we present results on the cluster angular spread (AS), the tap AS and its variation with different channel bandwidths for a measured large office environment. The measurements were conducted in the 5 GHz band using a virtual cross antenna array at the receiver. A frequency domain space alternating generalized expectation maximization (FD-SAGE) algorithm is employed to estimate the multipath components. The clusters of the multipaths are then manually identified. For each measured location, 4 - 5 clusters are identified and the processed results show that the cluster AS ranges 5.6° 36.5°. Furthermore, we investigate the tap AS for each cluster. It is found that for the channels with 100 MHz bandwidth, the instantaneous tap AS ranges 0° - 43° and the average tap AS of each cluster is just few degrees less than the AS of that cluster. The difference between the average tap AS and the cluster AS becomes smaller for less channel bandwidth.