Method and apparatus are provided for estimating first downlink (DL) channel information of first DL channels in accordance with reference signals received on first uplink (UL) channels, the first UL channels being a subset of available UL channels, and the first DL channels corresponding to the first UL channels. Channel feedback is received for a set of DL channels, and second DL channel information is estimated in accordance with the estimated first DL channel information and the received channel feedback.

Methods, systems, and devices for wireless communications are described. A first device may receive a first reference signal from a second device and may generate a channel status feedback message based on the first reference signal. The first device may bundle the second reference signal and the channel status feedback message and may transmit the second reference signal and the channel status feedback to the second device. The first device may initiate a data transfer with the second device based on transmitting the second reference signal and the channel status feedback message.

A method, wireless device and network node for CSI feed-back with multiple interference hypotheses are disclosed. According to one aspect, a method implemented in a wireless device (WD) includes receiving a configuration for Channel State Information (CSI) measurement including a first Non-Zero Power Channel State Information-Reference Signal (NZP CSI-RS) resource set for channel measurement and a second NZP CSI-RS resource set for interference measurement, the first NZP CSI-RS resource set having only one NZP CSI-RS resource. The method also includes measuring CSI based on the first and the second NZP CSI-RS resource sets.

A transmitter includes a first measurement unit configured to measure a radio wave environment between the transmitter and a receiver for an individual wireless resource, a transmission control unit configured to determine the wireless resource and a parameter on a basis of the measurement result of the radio wave environment, an encoder unit configured to perform distributed coding of the bit sequence on a basis of the parameter, and a transmission unit configured to transmit information representing the determined wireless resource and the distributed coded bit sequence, by using the determined wireless resource. The receiver includes a second measurement unit configured to measure the radio wave environment for the individual wireless resource, a reception control unit configured to estimate the parameter on a basis of the measurement result of the radio wave environment, a reception unit configured to receive the information representing the determined wireless resource and the distributed coded bit sequence, by using the determined wireless resource, and a decoder unit configured to decode the received bit sequence on a basis of the parameter.

Introduced here is at least one technique to better estimate interference at a receiver. The technique includes receiving a plurality of reference signals, which each have information indicative of noise. Thus, the technique further includes, for each reference signal, determining a noise estimation and determining a distance metric and log-likelihood ratio (LLR) of the noise estimation. Once the distance metric and LLR of each reference signal is determined, the receiver can determine a final LLR based on the distance metric and LLR of each reference signal. In this manner, a final LLR is determined. This technique can be applied by any device operating on MIMO technology.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, an apparatus of a user equipment (UE) may receive, from a base station, a physical downlink control channel (PDCCH) indicating a configuration for one or more of demodulation reference signal (DMRS) bundling that is to be used for channel estimation by the base station for a first group of physical uplink control channels (PUCCHs) or frequency hopping for a second group of PUCCHs. The apparatus may transmit, to the base station, one or more PUCCHs based at least in part on the configuration. Numerous other aspects are described.

In a multiuser (MU) multiple antenna system (MAS), a central processing unit is communicatively coupled to multiple distributed wireless terminals (WTs) via a network. The central processing unit processes channel measurements indicative of channel conditions between the multiple distributed WTs and a plurality of user devices and selects a plurality of WTs from the multiple distributed WTs to enhance channel space diversity within the MU-MAS. The central processing unit calculates (Multiple Input, Multiple Output) MIMO weights from the channel measurements for precoding a plurality of data streams that are transmitted concurrently from the plurality of WTs to the plurality of users, wherein the MIMO weights provide for a plurality of independent MIMO channels.

A method for estimating a channel status by a base station in a wireless communication system according to an embodiment of the present invention comprises the steps of: obtaining an uplink channel matrix by using a sounding reference signal (SRS) received from a terminal; transmitting a channel state information-reference signal (CSI-RS) through at least some antenna devices in a two-dimensional antenna array of the base station; receiving a channel quality indicator (CQI) calculated on the basis of the CSI-RS transmission; and obtaining, through a predetermined correction factor obtained on the basis of the CQI and the uplink channel matrix, a downlink channel matrix for the entire two-dimensional antenna array comprising the remaining antenna devices through which the CSI-RS is not transmitted.

This invention presents methods for estimating the uplink SINR and channel estimation error level in MU-MIMO wireless communication systems comprising the BS obtaining the channel coefficients between each receiving antenna of a BS and a transmitting antenna of a UE in the uplink; for the BS estimating the SU-MIMO SINR of a UE using the channel coefficients between a UE and the BS; for the BS estimating the channel estimation error level of a UE using the channel coefficients between a UE and the BS.

A first radio signal is received that was transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna. The first radio signal is converted to a first orthogonal frequency division multiplexing (OFDM) frame signal, and the second radio signal is converted to a second OFDM frame signal. The first OFDM frame signal includes a grid of multiple frequency subcarriers and time periods, each time period with the frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes first OFDM symbols. A first OFDM symbol is carried on frequency subcarriers during a time period, and the first OFDM frame includes first reference OFDM symbols located at corresponding time-frequency resource elements in the grid. Each resource element is defined by a one of the frequency subcarriers and one of the time periods. The second OFDM frame signal is similar and includes second reference OFDM symbols sharing the same grid of frequency subcarriers and time periods as the first OFDM frame. But the second reference OFDM symbols are located at corresponding time-frequency resource elements in the grid different than the corresponding time-frequency resource elements to which the first reference OFDM signals are located their respective OFDM frame signals. The first and second reference OFDM symbols are used to demodulate the first and second OFDM frame signals.