Forward distortion correction for time domain beamforming

A network node configured to communicate with a wireless device, the network node configured to implement a time domain beamformer, the network node comprising circuitry configured to:

• filter each signal output by the time domain beamformer by a band stop filter, the band stop filter including a stop band overlapping a pass band of the signal output by the time domain beamformer;
• filter each signal output the time domain beamformer by a group delay filter in electrical parallel with a band stop filter, the group delay filter providing a group delay to the signal output by the time domain beamformer;
• and
• subtract an output of each band stop filter from an output of a corresponding group delay filter.

A network node configured to communicate with a wireless device, the network node comprising:

• a time domain beamformer configured to beam-form a plurality of signals to produce a plurality of time domain beamformer output signals;
• a plurality of band stop filters, each band stop filter of the plurality of band stop filter being configured to receive an output signal of the time domain beamformer;
• a plurality of group delay filters, each group delay filter of the plurality of group delay filters receiving an output signal of the time domain beamformer and being in electrical parallel with a band stop filter of the plurality of band stop filters;
• and
• a plurality of summation circuits, each summation circuit configured to subtract an output of a band stop filter of the plurality of band stop filters from an output of a corresponding group delay filter of the plurality of group delay filters.

A method in a network node configured to communicate with a wireless device, the method comprising:

• beamforming a plurality of signals to produce a plurality of time domain beamformer output signals;
• filtering each signal of the plurality of signals by a band stop filter, each band stop filter being configured to receive an output signal of the time domain beamformer;
• group delay-filtering each signal of the plurality of signals by a of group delay filter, each group delay filter being configured to receive an output signal of the time domain beamformer and being in electrical parallel with a band stop filter;
• and
• for each band stop filter, subtracting an output of a band stop filter from an output of a corresponding group delay filter.