A radio station, in particular an access point, for client localization in a multipath indoor environment is disclosed. The radio station comprises: a circular antenna array comprising uniform circularly arranged antenna elements; and a processor configured to: transform first input data from the circular antenna array into second input data using a transform that transforms the first steering vector of the circular antenna array into a second steering vector of a virtual linear antenna array; and transform the second input data into third input data by using a transform that transforms the second steering vector of the virtual linear antenna array into a third steering vector of a second virtual linear antenna array, comprising a larger number of antenna elements than the virtual linear antenna array; and determine an angle of arrival based on the third input data.