Patent ID: 8817686

Claim:
A network, comprising: a relay node configured to transmit a first common reference signal (CRS) to a plurality of user agents (UAs) using a first plurality of physical antennas and/or virtual antennas; and an access node configured to transmit a second CRS to the UAs using a second plurality of physical antennas and/or virtual antennas, wherein the first CRS and the second CRS are combined for the same number of first and second physical antennas and/or virtual antennas, wherein the UAs receive a combined CRS comprising the first CRS and the second CRS transmitted using the same number of first and second physical antennas and/or virtual antennas, and wherein the UAs separately receive the first CRS and the second CRS transmitted using a different number of first and second physical antennas and/or virtual antennas, wherein the UA receives a first channel matrix from the relay node and a second channel matrix from the access node and estimates a Precoding Matrix Indicator (PMI) using a composite channel matrix comprising the first channel matrix and the second channel matrix for MIMO transmissions.