Downlink beamforming avoiding DOA estimation for cellular mobile communications

A new technique to overcome the induced difficulties of FDD (frequency division duplex) for the design of a forward link beamformer in cellular mobile communications systems is presented. It takes advantage of the array topology at the basestation, used to transpose second order statistics of the propagation channel from the uplink frequency to the downlink frequency, thus enabling one to optimize directly any beamforming criterion based on these statistics at the downlink frequency, without feedback nor DOA (direction of arrival) estimation. It can be applied whatever the criterion used to design the beamformer. The effectiveness is verified by the mean of simulation results.