Methods and apparatuses are described for a Node B to transmit Reference Signals (RS) from multiple antennas to enable User Equipments (UEs) to perform demodulation of received information signals and to estimate Channel Quality Indication (CQI) metrics. To minimize overhead and enable backward compatible operation with legacy systems, RS from a first set of Node B antennas are transmitted in every transmission time interval and substantially over the whole operating BandWidth (BW). RS from a second set of Node B antennas serving for CQI estimation are periodically transmitted, substantially over the whole operating BW, with transmission period informed to UEs through broadcast signaling by the Node B and starting transmission sub-frame determined from the identity of the cell served by the Node B. RS from the second set of antennas, and new RS from the first set of antennas, serving for demodulation of information signals have substantially the same BW as the information signals which can be smaller than the operating BW.