Abstract: A method and an apparatus for performing multiple-input multiple-output (MIMO) wireless communications are disclosed. A Node-B may receive an index to a pre-coding matrix in a single user MIMO (SU-MIMO) pre-coding codebook from wireless transmit/receive units (WTRUs) and adaptively perform one of SU-MIMO or multi-user MIMO (MU-MIMO) based on a predetermined criterion. Channel information for performing MU-MIMO may be obtained based on the pre-coding matrix of the SU-MIMO pre-coding codebook. A rank requested by the WTRU may be overridden if the unitary MU-MIMO codebook is a subset of the SU-MIMO pre-coding codebook. If not, a MU-MIMO pre-coding matrix with a largest correlation to the pre-coding matrix may be selected. A WTRU may send a pre-coding matrix for transmission to the WTRU along with a preferred interference matrix. A WTRU may send rank information and multiple right singular vectors for MU-MIMO.

Abstract: A method and apparatus are used to support single user (SU) and multiuser (MU) beamforming with antenna array groups. The method and apparatus are used to precode a plurality of data streams, beamform each of the data streams, and provide each of the beamformed data streams to one of a plurality of antenna array groups. An alternate method and apparatus are used to select a beamforming vector from a codebook, transmit a common reference signal (RS) based on the selection, receive an antenna configuration responsive to the common RS, estimate channels based on the antenna configuration, determine beamforming vectors for a plurality of antenna array groups, and transmit the beamforming vectors.

Abstract: A method and an apparatus are provided for receiving a transport block that is segmented into a plurality of code blocks (CBs), each CB having an attached cyclic redundancy check (CRC), decoding each of the plurality of CBs with attached CRC, determining whether each CRC fails, and in response to a determination that a CRC has failed, transmitting a CB index number of the CB attached to the CRC that has failed. Also provided are a method and an apparatus for a transmitter receiving an index number of a CB for retransmission (CBSIRT) attached with a CRC that has failed, determining the CB that correspond to the CRC that has failed based on the CBSIRT, and retransmitting the failed CB in a subsequent transmission time interval (TTI).

Abstract: A method and system selects a subset of antennas from a set of antennas to transmit user data in a wireless communication system. The user data is transmitted during a first transmission time intervals (TTI) using a first subset of antennas. Pilot tones are transmitted during a second TTI using a second subset of antennas. Corresponding channel qualities are estimated for the first subset of antennas and the second subset of antennas from the user data and the pilot tones. Then, based on the estimating, a best subset of antenna is selected from the first subset of antennas and the second subset of antennas to transmit the user data during a subsequent TTI.

Abstract: A method and apparatus for receiving and processing channel quality index (CQI) reporting. A wireless transmit receive unit is configured to receive CQI configuration information and transmit a CQI report based on the CQI configuration information.

Abstract: A method and apparatus for generating channel quality indicator (CQI), precoding matrix indicator (PMI) and rank information are disclosed. The method and apparatus reduces feedback overhead and defines differential CQI information in an orthogonal frequency division multiplex (OFDM) symbol.

Abstract: A method and apparatus for signaling interference information in a multi-user multiple-input multiple-output (MU-MIMO) system including a plurality of wireless transmit/receive units (WTRUs) and a base station are disclosed. The method includes the base station signaling interference information including rank information or a number of WTRUs to a particular WTRU based on beamforming vector feedback information received from the WTRUs. In order to reduce the downlink signaling overhead, confirmation of the beamforming vector feedback from WTRUs is used. The interference beamforming vectors and rank information or the number of WTRUs can be signaled separately or jointly.

Abstract: A wireless communication method and apparatus for creating a codebook in a multiple input/multiple output (MIMO) wireless communication system are disclosed. The method includes adapting a single user codebook, wherein the single user codebook comprises a plurality single user beamforming vectors, into a multi-user codebook, wherein the multi-user codebook comprises a plurality of multi-user beamforming vectors. The method further includes grouping the codebook into a plurality of unitary matrices, selecting a plurality of beamforming vectors from the plurality of unitary matrices, forming a rank specific code-book from the beamforming vectors and the unitary matrices, and selecting a subset of a total number of pairs to form the plurality of unitary matrices.

Abstract: A method and apparatus generates a codebook and associated scheduling and control signaling. A plurality of channel combinations is generated for a plurality of wireless transmit receive units (WTRUs). The channel for each WTRU is quantized based on the WTRU codebook. A codebook for beamforming is generated for a plurality of WTRUs. The codebook includes a plurality of beamforming matrices. All possible beamforming matrices may be computed and the codebook may be quantized.

Abstract: A method and system generating signal to select a subset of antennas from a set of antennas to transmit user data in a wireless communication system. User data are transmitted during a first transmission time intervals (TTI) using a first subset of antennas. Pilot tones are transmitted during a second TTI using a second subset of antennas. Corresponding channels are estimated for the first subset of antennas and the second subset of antennas from the user data and the pilot tones. Then, based on the estimating, an optimal subset of antenna is selected from the first subset of antennas and the second subset of antennas to transmit the user data during a sequent TTI, and in which the selecting is performed adaptively.

Abstract: A method and system switches antennas in an orthogonal frequency division multiplexed access (OFDMA) wireless communication system while transmitting symbols. Each symbol includes a cyclic prefix and a block of data signals. The symbols are transmitted during a first portion of a transmission time interval (TTI), from a first antenna. Then, the RF chain is switched to a second antenna to transmit the symbols, and in which the switching is performed substantially between transmitting two consecutive transmitted symbols.

Abstract: A method and system selects a subset of antennas from a set of antennas to transmit user data in a wireless communication system. The user data is transmitted during a first transmission time intervals (TTI) using a first subset of antennas. Pilot tones are transmitted during a second TTI using a second subset of antennas. Corresponding channel qualities are estimated for the first subset of antennas and the second subset of antennas from the user data and the pilot tones. Then, based on the estimating, a best subset of antenna is selected from the first subset of antennas and the second subset of antennas to transmit the user data during a subsequent TTI.