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 wireless communication system non-collaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system determines subscriber station combining and weighting vectors that yield a high average signal-to-interference plus noise ratio (SINR). Each subscriber station independently transmits information to a base station that allows the base station to determine a weight vector w.sub.i for each subscriber station using the determined combining vector of the subscriber station. The i.sup.th combining vector corresponds to a right singular vector corresponding to a maximum singular value of a channel matrix between a base station and the i.sup.th subscriber station. Each subscriber station transmits signals using a weight vector v.sub.i, which corresponds to a left singular vector corresponding to a maximum singular value of a channel matrix between the i.sup.th subscriber station and the base station. The base station uses the weight vector w.sub.i to determine the signal transmitted by the i.sup.th subscriber station.

Methods, systems, and devices for wireless communications are described. For example, a user equipment (UE) may receive one or more reference signals from a base station. In some examples, the UE may receive the one or more reference signals over a channel for communications between the UE and the base station. The UE may measure a response of the channel based on the one or more reference signals received over the channel. In some examples, the UE may transmit a message indicating a set of channel coefficients. The set of channel coefficients may correspond to a two-dimensional (2D) model representative of the response. In some examples, the 2D model may include a spatial model and a time domain response of the channel.

An operating method of a power estimation apparatus comprising a fixed antenna and a mobile antenna may comprise: a first operation of obtaining N measurement values by receiving a signal from signal sources using the fixed antenna and the mobile antenna that moves at a speed v from a first point to an Nth point; a second operation of generating a two-dimensional (2D) data collection set comprising N×M measurement values, by repeating the first operation M times; applying an approximation singular value decomposition (SVD) algorithm to the 2D data collection set; and obtaining information of the signal sources based on an application result of the approximation SVD algorithm, wherein N and M are natural numbers.

Embodiments of this application disclose a channel estimation method and apparatus, and relate to the field of communications technologies. One example method include: generating and sending indication information, where the indication information is used to indicate L space-frequency basis vectors for constructing an M×N-dimensional space-frequency vector; the space-frequency vector includes M N-dimensional precoding vectors, each precoding vector is used in one of M frequency bands, and the space-frequency vector is generated by performing a weighted combination on L space-frequency component vectors; each of the L space-frequency component vectors is a vector including M×N elements that are in one of the L space-frequency basis vectors, and each of the L space-frequency basis vectors is an N.sub.f×N-dimensional vector; the space-frequency basis vector is a three-dimensional oversampled (DFT) vector; and L≥2, N.sub.f≥M≥1, N≥2, and L, M, N, and N.sub.f are all integers.

A wireless communication system non-collaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system determines subscriber station combining and weighting vectors that yield a high average signal-to-interference plus noise ratio (SINR). Each subscriber station independently transmits information to a base station that allows the base station to determine a weight vector w.sub.i for each subscriber station using the determined combining vector of the subscriber station. The i.sup.th combining vector corresponds to a right singular vector corresponding to a maximum singular value of a channel matrix between a base station and the i.sup.th subscriber station. Each subscriber station transmits signals using a weight vector v.sub.i, which corresponds to a left singular vector corresponding to a maximum singular value of a channel matrix between the i.sup.th subscriber station and the base station. The base station uses the weight vector w.sub.i to determine the signal transmitted by the i.sup.th subscriber station.

An operation method of a first receiving node in a distributed communication system may comprise: receiving a signal from a transmitting node; extracting a combined signal vector from a reception signal vector corresponding to a vector of the received signal; obtaining a compressed combined signal vector by extracting a preset number T of combined signal elements from among a plurality of combined signal elements constituting the combined signal vector; quantizing the compressed combined signal vector to obtain a quantized combined signal vector; and transmitting the quantized combined signal vector to a second receiving node included in the distributed communication system.

Certain aspects of the present disclosure relate to a technique for communicating Channel State Information (CSI) feedback. In some aspects, the CSI feedback is communicated in a very high throughput (VHT) wireless communications system.

A MIMO system (100) and a method of generating a precoder for use in a MIMO system (100), when communicating with a UE (115), are provided. The method comprises receiving, from the UE (115), channel information relating to a channel on which data is transmitted; decomposing the channel information into components representing a transmission component and a signal strength component; and generating the precoder according to the transmission component and the signal strength component.

Embodiments of a method and an apparatus for beamforming are disclosed. In an embodiment, a method for beamforming involves transmitting, by a beamformer to a beamformee, a sounding packet that includes training symbols, receiving, at the beamformee, the sounding packet that includes the training symbols, deriving, at the beamformee, channel estimates from the training symbols included in the sounding packet, computing, at the beamformee, a feedback matrix from the derived channel estimates, transmitting, by the beamformee to the beamformer, a packet that includes two sets of symbols, where the feedback matrix is applied to at least one of the two sets of symbols, receiving, at the beamformer, the packet that includes the two sets of symbols, and operating the beamformer according to the two sets of symbols included in the packet.