Patent ID: 11304238

Abstract:
In a beamforming system, each User Equipment (UE) transmits an uplink probe. Each Base Station (BS) carries out a spatial search of the uplink probes, estimates an Angle of Arrival (AoA) of the uplink probe received from each UE, and estimates the uplink channel frequency response on an uplink dedicated beam formed toward the UE's AoA. The BS transmits a reference signal to each UE on a downlink dedicated beam formed toward the UE's AoA, from which the UE estimates the downlink frequency response. The UE forms channel impulse response matrices for the uplink and the downlink, using the estimated uplink and downlink channel frequency responses. The BS uses the channel impulse response matrices to form downlink and uplink dedicated beams that put boresight of the beams toward the AoA of one UE and put nulls toward the AoAs of the other UEs.