A wireless device may support a plurality of channel state information (CSI) processes. The wireless device may send an indication of a number of supported CSI processes to a first base station. The first base station may send to the wireless device a handover command, instructing the wireless device to handover to a second base station. The handover command may comprise configuration parameters for CSI processes associated with the second base station. The configuration parameters may be based on the number of CSI processes supported by the wireless device.

A method of an RFC chip for a station, the RFC chip including a WLAN communication module to decode a DL MU-MIMO wireless signal, the method including: determining an FS layer column based on a product of a channel matrix of the station and an estimate of a steering matrix of the station; ordering columns of a sub-matrix of an effective channel matrix of the station to determine one or more SS layer columns from the sub-matrix, the sub-matrix being determined by removing, from the effective channel matrix, a column corresponding to the determined FS layer column; configuring a modified effective channel matrix based on the determined FS layer column and the ordered columns of the sub-matrix, the determined FS layer column being determined as an FS layer column of the modified effective channel matrix; and determining a symbol of the station based on the modified effective channel matrix.

A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

According to some aspects, a first base station employing a first beamforming codebook may receive a second beamforming codebook from a second base station. The first beamforming codebook may comprise a plurality of beamforming codewords associated with the first base station, and the second beamforming codebook may comprise a plurality of beamforming codewords associated with the second base station. The first base station may receive at least one message from the second base station indicating a subset of the plurality of beamforming codewords associated with the second base station. The first base station may select one or more first beamforming codewords from the first beamforming codebook based on the indicated subset of the plurality of codewords associated with the second base station. The first base station may transmit signals to at least one wireless device employing the one or more first beamforming codewords.

Methods, apparatus, and systems for wireless communications are described. Example methods, devices, and systems are described that utilize a precoding matrix indicator (PMI) computed based at least in part on first signals received via a first cell and on second signals received via a second cell. Information in a measurement information message may be used as part of computing a PMI. The measurement information message may indicate resources of a first cell and a second cell for use in computing the PMI. A wireless device may receive first signals via the first cell and second signals via the second cell based on information in the measurement information message, and may use these signals to compute the PMI. The computed PMI may be used in communications with a base station. For example, the wireless device may receive a packet beamformed employing the computed PMI.

Methods, apparatus, and systems for wireless communications are described. A first base station may be configured to transmit a measurement information message to a wireless device. The measurement information message may comprise at least one information element, wherein the at least one information element indicates one or more first resource blocks corresponding to first signals associated with the first base station and one or more second resource blocks corresponding to second signals associated with a second base station. The wireless device may compute a precoding matrix indicator (PMI) based at least in part on first signals received from the first base station and second signals received from the second base station. The wireless device may transmit channel state information comprising the computed PMI to the first base station. The first base station may transmit at least one data packet beamformed according to a precoding matrix associated with the computed PMI.

Methods, apparatus, and systems for wireless communications are disclosed. A first base station may be configured to receive, from a second base station, one or more messages. The messages may include downlink beamforming information elements for a downlink cell. Each downlink beamforming information element of the plurality of downlink beamforming information elements may be associated with a respective resource block of a plurality of resource blocks in the downlink cell. The first base station may select a first beamforming codeword for at least one resource block of the plurality of resource blocks based on the downlink beamforming information associated with the at least one resource block. The first base station may transmit, to a wireless device, signals on the at least one resource block employing the first beamforming codeword.

Systems and methods are disclosed for utilizing unused bit resources to convey restrictions on parameters evaluated for a feedback report in a Multiple-Input Multiple-Output (MIMO) wireless communication system. In one embodiment, a method of operation of a transmitting node in a wireless network includes transmitting a feedback restriction indicator to a receiving node, where the feedback restriction indicator is an unused bit resource in one or more instances of a control channel that is indicative of one or more desired restrictions on parameters to be evaluated by the receiving node for a feedback report to be provided from the receiving node. The method of operation of the transmitting node further includes receiving the feedback report from the receiving node, where the feedback report is limited according to the feedback restriction indicator.

A first base station receives from a second base station at least one message comprising beamforming information indicating at least one second beamforming codeword. The at least one second beamforming codeword has a number of rows or columns equal to or less than a number of antenna ports employed by the second base station for beamforming. The first base station selects at least one first beamforming codeword. The selection is based, at least in part, on the beamforming information. The first base station transmits employing the at least one first beamforming codeword, signals on at least one resource block.

A method for operating a base station includes receiving an uplink signal from a user equipment (UE), wherein the uplink signal includes a precoding matrix indicator (PMI) associated with a first precoder index of a codebook determined by a first and a second precoder indices, and a channel quality indicator (CQI). The method includes applying an open-loop diversity operation to at least one data stream including quadrature amplitude modulation (QAM) symbols to generate N_B signal streams and applying a precoding matrix to the N_B signal streams to generate a larger number of N_TX data streams to be transmitted via a plurality of antennas.