A wireless transmit/receive unit (WTRU) is configured to receive a reference signal of a first type. The reference signal of the first type is other than a cell specific reference signal (CRS), an Multicast Broadcast Single Frequency Network (MBSFN) reference signal or a demodulation reference signal (DM-RS). Reference signals of the first type are received in resource elements other than resource elements used for a physical broadcast channel (PBCH), a primary synchronization signal or a secondary synchronization signal. The WTRU is configured to receive a radio resource control message indicating a subframe position in which the reference signal of the first type is transmitted and a periodicity of a transmission of the reference signal of the first type, and a number of antenna ports for a transmission of the reference signal of the first type.