This application describes a channel information feedback method and a communication apparatus. The method includes a terminal device that receives configuration information sent by a network device, where the configuration information is used to configure a feedback mode of channel information. The terminal device may feed back current channel information to the network device when the feedback mode configured by using the configuration information is a first mode. The terminal device may alternatively feeds back predicted channel information to the network device when the feedback mode configured by using the configuration information is a second mode. System performance is therefore improved by the method described in this application because channel information feedback requirements in different scenarios can be met. In particular, a problem that data transmission performance deteriorates because channel information expires in a moving scenario can be resolved by feeding back the predicted channel information.

Device, methods and systems for aspects of channel estimation for orthogonal time frequency space (OTFS) modulation in wireless systems are described. In an aspect, a method for wireless communication may include receiving, using multiple receive antennas, from a number of user devices, non-orthogonal pilots wherein at least some transmissions of the non-orthogonal pilots from different user devices overlap in at least some time and frequency resources, estimating individual pilots from the number of user devices by computing a pilot separation filter for each antenna, and estimating the wireless channel at time and frequency resources used by the non-orthogonal pilots by filtering the receiving signal at the multiple receiver antennas.

A repetition unit (212) performs a repetition for mapping a data signal and a demodulation reference signal (DMRS) repeatedly at a symbol level over a plurality of subframes. A signal allocation unit (213) maps, in the a plurality of subframes, the repeated DMRS to symbols other than symbols corresponding to an SRS resource candidate, which is a candidate for a resource to which a sounding reference signal (SRS) to be used to measure an uplink received signal quality is to be mapped. A transmission unit (216) transmits an uplink signal (PUSCH) including the DMRS and the data signal over the a plurality of subframes.

A wireless device (14) receives a downlink reference signal (24) from a radio network node (12) over a downlink channel (16), and determines channel information (28) based on measurement of the downlink reference signal (24). The wireless device (14) then transmits, to the radio network node (12) over an uplink channel (18), an uplink signal (30) that implicitly conveys the determined channel information (28). The radio network node (12) jointly (i) identifies which candidate uplink signal in a set (32) of candidate uplink signals (30-1 . . . 30-N) is received; and (ii) determines an estimate (42) of the uplink channel (18) from the received uplink signal (30). The radio network node (12) determines the channel information (28) implicitly conveyed by the identified candidate uplink signal, and then determines an estimate (22) of the downlink channel (16) based on the determined channel information (28) and the determined estimate (42) of the uplink channel (18).

Embodiments of this application disclose methods and apparatuses for obtaining channel parameters. In an implementation, a method includes, sending, by a network device, a precoded reference signal and indication information indicating K selected frequency domain bases, wherein the precoded reference signal is generated on P ports by mapping K virtual ports associated with the K selected frequency domain bases to each of the P ports through beamforming, wherein K is an integer greater than 1, and wherein the P ports are precoded channel state information reference signal (CSI-RS) ports of the network device and user equipment, and receiving, by the network device, a linear superposition coefficient sent by the user equipment, wherein the linear superposition coefficient corresponds to M frequency domain bases in the K selected frequency domain bases and T ports in the P ports, wherein 1≤T≤P, and 1≤M≤K.

Systems, methods, and devices to reduce the channel estimation overhead by collecting data from many UEs and building a location-based mathematical model are disclosed. During building of the model, a reference signal is used to collect location- and signal-related data from connected UEs. Once the model is successfully built, it is then transmitted and/or downloaded to each new UE that connects to the base station. The UEs and/or the base stations then use this model to determine their own transmission parameter values. The UEs also report their location to the base stations, which use the model to estimate channel conditions and adapt transmission parameters for themselves.

Techniques described herein can facilitate Channel-State Information (CSI) measurement and feedback for communication in unlicensed spectrum or Sounding Reference Signal (SRS) transmission and/or channel-state estimation for communication in unlicensed spectrum. In an example, an apparatus is configured to be employed in a User Equipment (UE), and the apparatus comprises a Radio Frequency (RF) circuitry interface and processing circuitry configured to perform CSI measurement for communication in unlicensed spectrum. The apparatus further generates data for feedback according to the CSI measurement, and sends the data for feedback to RF circuitry via the RF circuitry interface. In an example, a frame structure of a data channel begins with a downlink (DL) transmission or soon after an initial signal. In an example, the CSI measurement includes measuring Channel Quality Information (CQI) for one or more sub-bands.

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. The present invention relates to a method and device for decoding data by a base station in a wireless communication system, and the method of the present invention comprises the steps of: transmitting, by a base station, phase tracking reference signal (PTRS) allocation information, which includes PTRS port information and orthogonal cover code (OCC) information, to a terminal; receiving, from the terminal, a demodulation reference signal (DMRS) and a PTRS to which an OCC depending on the OCC information has been applied, so as to estimate phase noise; and compensating the phase noise to decode data received from the terminal.

A method for minimizing a time domain mean square error (MSE) of channel estimation (CE) includes estimating, by a processor, a power delay profile (PDP) from a time domain observation of reference signal (RS) channels; estimating, by the processor, a noise variance of the RS channels; and determining, by the processor, a first arrival path (FAP) value and a delay spread estimation (DSE) value based on the estimated PDP and the estimated noise variance for minimizing the MSE of CE.

The present disclosure provides a method for performing radio link monitoring (RLM) by a terminal for which a plurality of carriers are configured, in a wireless communication system. Specifically, the method may comprise: receiving a reference signal through one carrier among the plurality of carriers: measuring the radio link quality of the one carrier on the basis of the reference signal, and determining whether wireless communication through the plurality of carriers is possible, on the basis of the measured radio link quality.