Symmetric and full duplex relay in wireless systems

A method for Multiple Input Multiple Output (MIMO) wireless communication systems comprising

• beamforming two or more spatial multiplexed streams, by a Base Station (BS) with a plural of antennas with two or more antennas on User Equipment (UEs) wherein each UE has a sufficient number of antennas to receive and/or transmit one or more spatial multiplexed streams,
• using one or more relays, whose total number of antennas is sufficient to support the two or more spatial multiplexed streams and whose Downlink (DL) and Uplink (UL) Radio Frequency (RF) circuit paths are symmetric with closely matched transfer functions, to project the capacity of the BS to cover one or more UEs,
• estimating, by the BS, the uplink Channel State Information (C SI) between each antenna on the BS and each antenna on the one or more UEs using pilots transmitted from the UE antennas in the presence of the relays which amplifies and forwards the one or more pilots;
• and,
• making use of, by the BS, the perseverance of the reciprocity of the over the air channel by the symmetry of the DL and UL RF circuit paths of the one or more relays to obtain the downlink Total Channel CSI using the estimated uplink Total Channel CSI that includes the effect of the relays.