A method of transmission over multiple wireless channels in a multiple antenna system includes storing channel modulation matrices at a transmitter; receiving quantized channel state information at the transmitter from plural receivers; selecting a transmission modulation matrix using the quantized channel state information from the stored channel modulation matrices; and transmitting over the multiple channels to the plural receivers using the selected transmission modulation matrix. In another embodiment, the method includes storing, at one or more receivers, indexes of modulation matrices generated by a capacity enhancing algorithm; upon a selected one of the one or more receivers receiving a transmission from the transmitter, the selected receiver selecting a modulation matrix from the stored modulation matrices that optimizes transmission between the transmitter and the selected receiver; the selected receiver sending an index representing the selected modulation matrix; and receiving the index at the transmitter from the selected receiver.

A method for transmitting channel state information performed by a User Equipment (UE) may include receiving, from a base station, a bitmap for configuring codebook subset restriction (CSR) and reporting, to the base station, Channel State Information (CSI), when a number of antenna ports is configured as 16 or more and a number of layers associated with a rank indicator (RI) in the CSI is 3 or 4, a unit of multiple bits in a bitmap for configuring the CSR is associated with each precoder, and a reporting of precoding matrix indicator (PMI) corresponding to the precoder associated with the multiple bits is restricted in the CSI, when the CSR is indicated in any one of the multiple bits, and each bit in the bitmap for configuring the CSR is associated with each precoder.

A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI (codebook index i.sub.2), wherein values 0-15 are assigned to the second PMI I.sub.PMI2 for RI=1 and values 0-3 are assigned to the second PMI I.sub.PMI2 for each of RI=2, RI=3, and RI=4, and wherein codebook index i.sub.2 comprises I.sub.PMI2 for RI=1. Other methods, apparatuses, and systems also are disclosed.

An approach is described that includes receiving a CSI report, where the CSI report includes a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI). The approach further includes constructing a precoding matrix based on a linear combination of a plurality of mutually orthogonal digital Fourier transformation (DFT) spatial beams, and determining a number of bits for the PMI of the precoding matrix. The approach also includes determining a space frequency matrix based, at least in part, on the number of bits for the PMI and the precoding matrix, and compressing the space frequency matrix. Finally, the approach includes determining a compressed PMI based, at least in part, on the space frequency matrix.

A system and method for the efficient compression of the Channel State Information (CSI) in a wireless network with very low complexity and implementation cost. In accordance with the present invention, the CSI can be approximated as the summation of very few sinusoids on constant frequencies and the parameters of the sinusoids can be found efficiently by very simple calculations such as dot products of vectors which are implementable in hardware at very low cost.

Differential feedback within multiple user, multiple access, and/or MIMO wireless communications. After full feedback signal(s) have been received by a communication device (e.g., one that is to be performing beamforming for use in subsequent signal transmission), differential feedback signal(s) are received. Those differential feedback signal(s) are employed to update the full feedback signal(s) thereby generating updated/modified full feedback signals. Over time, such updated/modified full feedback signals may subsequently be further updated based upon later received inferential feedback signal(s). Such differential feedback signaling takes advantage of time and/or frequency correlation in a communication channel to provide for reduced feedback overhead by feeding back a difference or delta (Δ) relative to a previous value. For example, instead of providing full feedback signals in each respective/successive communication, feedback overhead is reduced by providing a difference or delta (Δ).

Methods, systems, and devices for wireless communications are described. The method may include a user equipment (UE) transmitting, to a base station, signaling indicating a capability of the UE to utilize a demodulation reference signal (DMRS) for channel state information (CSI) reporting. Upon receiving the signaling, the base station may transmit the DMRS and the UE may update a parameter of a CSI report in response to the received DMRS. The UE may then transmit the CSI report to the base station and the base station may utilize the CSI report for subsequent communications with the UE.

The present disclosure relates to a communication method and system for converging a 5.sup.th-Generation (5G) communication system for supporting higher data rates beyond a 4.sup.th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Provided are a method and user equipment for sending feedback information to a base station. The method includes receiving a Channel Status Indication Reference Signal (CSI-RS) from the base station; generating feedback information on a basis of the received CSI-RS; and transmitting the generated feedback information to the base station, wherein generating feedback information includes selecting a precoding matrix for each antenna port group of the base station and selecting an additional precoding matrix on a basis of a relationship between the antenna port groups of the base station.

Aspects of the present disclosure relate to wireless communication. In some aspects, a user equipment may determine at least one of: a first number of coefficients to be included in a first set of coefficients in a transfer domain that characterize compressed channel state information (CSI) for a first layer, or a first quantization scheme to be used to interpret the first set of coefficients. The UE may determine at least one of: a second number of coefficients to be included in a second set of coefficients in the transfer domain that characterize the compressed CSI for a second layer, or a second quantization scheme to be used to interpret the second set of coefficients. The UE may transmit a report that identifies the first set of coefficients and the second set of coefficients based at least in part on the determination(s). Other aspects are provided.

Disclosed is a method for use in a multiple-input multiple-output (MIMO) communication network in which the network includes a plurality of cells provided by one or more base stations operable to transmit signals on at least one downlink to, and receive signals on at least one uplink from, one or more user equipments. A user equipment feeds back to the network reports on channel state information, CSI, relating to one or more channels between base stations and that user equipment, and base stations adapt downlink signals to user equipments based on the CSI reports, the method including: identifying uplink resources for a user equipment-initiated channel state message; the user equipment judging a need for a user equipment-initiated channel state message based on information not available to the network; and the user equipment sending the user equipment-initiated channel state message to the network using the uplink resources identified.