1. A method comprising: observing a predetermined number of spatial signatures for a communications channel between a base station and a mobile terminal during a predetermined time period; calculating transform matrices using a most recently observed spatial signature and one or more previously observed spatial signatures; generating at the base station one or more test spatial signatures from a previously observed spatial signature that form a vector space about the previously observed spatial signature based on the transform matrices such that the vector space is wider than a vector space associated with the observed predetermined number of spatial signatures; and deriving beamforming weights based on the one or more test spatial signatures for beamforming a transmission to the mobile terminal via an antenna subsystem of the base station, wherein the beamforming weights are configured to generate a wider de-focused beam relative to beamforming weights generated from the observed predetermined number of spatial signatures.