A communication apparatus comprises a generator that generates frequency resource position information corresponding to a first information which is based on the communication quality information received from user equipments, the frequency resource position information indicating validity or invalidity of the first information for each frequency resource, and a transmitter that transmits the first information, the frequency resource position information and a cell ID which the frequency resource position is applied, to another communication apparatus via a backhaul.

Embodiments are provided to enable concurrent uplink transmissions from multiple Wi-Fi stations (STAs) to one or more access points (APs) using Interference Alignment (IA). In an embodiment, the STAs broadcast, to one or more APs, beamforming reports including channel estimation information for downlink. The one or more AP then performs channel estimation using the beamforming reports, and selects at least some of the STAs. The AP also computes beamforming information for IA of uplink transmissions between the selected STAs and sends, to the selected STAs, the beamforming information. The beamforming information is piggy-backed over downlink data packets to the selected STAs. Each selected STA then sends an uplink data frame concurrently with one or more other uplink data frames from one or more other selected STAs to the AP. The uplink data frames are configured for concurrent uplink transmissions according to the beamforming information for IA.

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.

A communication apparatus comprises a generator that generates frequency resource position information corresponding to a first information which is based on the communication quality information received from user equipments, the frequency resource position information indicating validity or invalidity of the first information for each frequency resource, and a transmitter that transmits the first information, the frequency resource position information and a cell ID which the frequency resource position is applied, to another communication apparatus via a backhaul.

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.

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.

According to one or more aspects, a wireless device may transmit a message to a serving base station comprising parameters indicating that the wireless device supports configuration of a first quantity of channel state information (CSI) processes. The serving base station may transmit a message to the wireless device comprising measurement configuration parameters for the wireless device. The serving base station may transmit an indication of the measurement configuration parameters to a target base station in response to a determination to make a handover of the wireless device.

According to one or more aspects, a serving base station may transmit a message to a target base station based on a handover decision for a wireless device. The message may include first measurement configuration parameters for the wireless device and/or an indication of a number of channel state information (CSI) processes supported by the wireless device. The serving base station may receive a response from the target base station indicating second measurement configuration parameters for use by the wireless device after handover. The serving base station may transmit a handover command to the wireless device including the second measurement configuration parameters.

An apparatus includes means for determining to use a set of transmit antenna arrangements for spatial division multiplexing or single frequency network based simultaneous transmission across multiple antenna arrangement physical uplink shared channel transmission; and means for determining to use the set of transmit antenna arrangements for a physical uplink control channel resource transmission, in response to two different transmission configuration indicator states being indicated and the apparatus being configured to apply physical uplink shared channel precoding for simultaneous transmission across multiple antenna arrangement physical uplink shared channel transmission.

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.