Abstract: Methods and systems that enhance interference cancellation are described. Samples are obtained from stacked carriers in a received signal and a data vector is created from the samples. Stacked carriers are selected using a steering vector received during synchronization of the receiver. The steering vector is calculated to obtain cancellation of interference from another receiver and is calculated based on time domain channel estimation. Specialized time domain training sequences and simple cross correlation are used to obtain a channel estimate for use in stacked carrier beamforming and/or for use in OFDM based spatial beamforming. State space or filter based modeled interpolators in the frequency domain or time domain to interpolation of the channels, or whitening matrix-filters over time or frequency are used for maintaining linear beamforming weights as a function of time or frequency. Space time adaptive processing facilitates beamforming of communications signals OFDM and 802.16 (WiMax) systems.