A method for uplink channel estimation in time domain is disclosed. A base station transmits downlink signals to a user equipment before estimating uplink channel. The user equipment estimates downlink channel based on the received signals and feeds back channel tap positions of the estimated downlink channel. Finally, the base stations estimate the uplink channel based on the channel tap positions and pilots transmitted by the user equipment. A system and apparatus employing the method are also disclosed.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first network node may receive, from a second network node, codebook information that indicates a plurality of beams associated with an oversampled transmitter network node beamforming codebook. The first network node may transmit a beam selection report that indicates at least one suggested transmission beam associated with the oversampled transmitter network node beamforming codebook, wherein the beam selection report is based at least in part on a channel estimate that is obtained without obtaining beam measurements associated with beams that are associated with the oversampled transmitter network node beamforming codebook. Numerous other aspects are described.

A transmission apparatus (10) according to the present disclosure incudes: a correction value calculation unit (130) configured to calculate a correction value for correcting an initial standby time of a direct wave signal or an indirect wave signal based on a reception time of the direct wave signal and a reception time of the indirect wave signal that follows the direct wave signal, and a transmission time fluctuation compensation unit (140) configured to calculate the standby time by correcting the initial standby time using the correction value and cause the direct wave signal or the indirect wave signal to stand by in accordance with the standby time. The correction value calculation unit (130) calculates a correction value for increasing the standby time of the direct wave signal or reducing the standby time of the indirect wave signal.

A method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output are provided. The method implemented by an access point (AP) includes: sending, indication information to at least two stations (STAs), wherein the indication information indicates that the at least two STAs perform an uplink multiuser data transmission; receiving, uplink data sent by the at least two STAs through channels, respectively; and demodulating, the uplink data using receiving beams corresponding to pre-estimated channels, respectively. According to the embodiments of the present disclosure, the AP receives the uplink data from multiple STAs through different channels from the STAs to the AP respectively, and demodulates data using the receiving beams corresponding to the channels respectively, thereby realizing that the AP performs separation and demodulation of the uplink data sent by multiple STAs and realizing the uplink multiuser data transmission.

The embodiments of the present disclosure disclose a method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output. The method includes: sending, by an access point AP, indication information to at least two stations STAs, wherein the indication information is used for indicating that the at least two STAs perform an uplink multiuser data transmission; receiving, by the AP, uplink data sent by the at least two STAs through channels from the at least two STAs to the AP, respectively; and demodulating, by the AP, the uplink data sent by the at least two STAs using receiving beams corresponding to pre-estimated channels from the at least two STAs to the AP, respectively. According to the embodiments of the present disclosure, the AP receives the uplink data from multiple STAs through different channels from the STAs to the AP respectively, and demodulates data using the receiving beams corresponding to the channels respectively, thereby realizing that the ap perform separation and demodulation of the uplink data sent by multiple STAs and realizing the uplink multiuser data transmission.

This disclosure describes systems, methods, and devices related to multi-user uplink channel sounding. A device may determine a channel sounding sequence with one or more access points (APs), wherein the channel sounding sequence comprises a null data packet announcement (NDPA) communicated with at least one of the one or more APs. The device may determine a first group of station devices (STAs) associated with a first basic service set (BSS). The device may cause to send a trigger frame to the first group of STAs to solicit an uplink NDP from each STA of the first group of STAs. The device may identify a first uplink NDP received from a first STA of the first group of STAs. The device may identify a second uplink NDP received from a second STA of a second group of STAs.

The present disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as Long Term Evolution (LTE). The present disclosure provides a channel estimation method and apparatus by a reception end. The reception device includes a receiver and a controller. The receiver receives a reference signal. The controller identifies a first set of channel values for resources allocated for reference signals. The controller performs interpolation on the first set of channel values so as to identify second set of channel values for remaining resources. The interpolation method is determined based on at least one of Doppler frequency of a channel and channel quality. The controller processes received signals using the first set of channel values and the second set of channel values.

The embodiments of the present disclosure disclose a method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output. The method includes: sending, by an access point AP, indication information to at least two stations STAs, wherein the indication information is used for indicating that the at least two STAs perform an uplink multiuser data transmission; receiving, by the AP, uplink data sent by the at least two STAs through channels from the at least two STAs to the AP, respectively; and demodulating, by the AP, the uplink data sent by the at least two STAs using receiving beams corresponding to pre-estimated channels from the at least two STAs to the AP, respectively.

Certain aspects of the present disclosure relate to techniques for estimating a channel using soft-windowing. A user equipment (UE) may determine, based on a cyclic prefix (CP) length of a channel, a timing window for sampling reference signals transmitted on the channel, determine a set of weights to apply to samples obtained within the determined timing window, wherein each weight corresponds to a sample obtained within the determined window, and estimate the channel by applying the weights to the samples.

A method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output are provided. The method implemented by an access point (AP) includes: sending, indication information to at least two stations (STAs), wherein the indication information indicates that the at least two STAs perform an uplink multiuser data transmission; receiving, uplink data sent by the at least two STAs through channels, respectively; and demodulating, the uplink data using receiving beams corresponding to pre-estimated channels, respectively. According to the embodiments of the present disclosure, the AP receives the uplink data from multiple STAs through different channels from the STAs to the AP respectively, and demodulates data using the receiving beams corresponding to the channels respectively, thereby realizing that the AP performs separation and demodulation of the uplink data sent by multiple STAs and realizing the uplink multiuser data transmission.