Patent ID: 8477863

Claim:
A method for use by a base station in a wireless orthogonal frequency division multiplexing (OFDM) system using a plurality of antenna ports, wherein reference symbols facilitate channel estimation at a wireless transmit/receive unit (WTRU), the method comprising: determining a resource allocation for the WTRU, wherein the resource allocation indicates a number of subcarriers assigned to the WTRU for an OFDM block, and wherein the OFDM block being divided into sub-blocks defined by subcarriers and symbol time intervals; for each antenna port of the base station, in the OFDM block, transmitting data of at least one stream, antenna specific reference symbols of that antenna port and for each stream, precoded reference symbols, wherein for each antenna port, the antenna specific reference symbols are not in a same sub-block as the antenna specific reference symbols of another antenna port; wherein for each stream, the precoded reference symbols of that stream are included in a plurality of sub-blocks having different symbol time intervals and same subcarriers, wherein for at least one stream, the precoded reference symbols of that stream are included in a plurality of sub-blocks having different subcarriers and a same symbol time interval, and wherein the sub-blocks used for the antenna specific reference symbols and the precoded reference symbols are determined based on at least the resource allocation; and transmitting information indicating whether the precoded reference symbols for each stream are included in each stream.