Abstract: Embodiments of the present disclosure relate to hybrid beamforming. A plurality of time delay elements is used to perform analog beamforming. Each time delay element is configured to apply the same time delay at different frequencies. The plurality of time delay elements is coupled to at least one RF chain to receive signals. Each antenna in an antenna array is configured to be selectively connected to one of the plurality of time delay elements based on a target configuration of a connection between the plurality of time delay elements and the antenna array. In operation, the target configuration is determined based on time delay information concerning the plurality of time delay elements and channel information concerning a physical channel over which the signals are to be transmitted.

Abstract: Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media of a Channel State Information (CSI) feedback with low overhead. The method comprises in response to receiving, from a second device, a reference signal on a channel between the first device and the second device, obtaining a first component and a second component from the reference signal, the first component and the second component being orthogonal to each other; determining a first transformed component and a second transformed component for characterizing the channel by performing a transformation on the first component and the second component; generating a set of parameters associated with characteristics of the channel by quantizing the first transformed component and the second transformed component; and transmitting the set of parameters to the second device.

Abstract: Various example embodiments relate to devices and methods supporting beam selection adaptive to user equipment distribution. A network device may be configured to sweep a first set of beams predefined for a cell, determine one or more supplement beams for one or more user equipments in the cell, and sweep at least a portion of the one or more supplement beams. The one or more supplement beams are selected from a second set of beams different from the first set of beams.

Abstract: Embodiments of the present disclosure relate to a beamforming solution for MIMO communication. The method implemented at a first device comprises: obtaining: a signature vector corresponding to a beam which is in a first direction from the first device to a second device, and a first channel covariance matrix associated with a transmission from the first device to the second device. The method further comprises generating, based on the signature vector and the first channel covariance matrix, a beamforming matrix to be used for the transmission from the first device to the second device. In this way, the accuracy of the beamforming matrix is improved and the calculation amount for the beamforming matrix is reduced.

Abstract: Disclosed are communication methods for terahertz channel communication. An example communication method performed by a user equipment device may include receiving, from a network apparatus, mapping information on property of distance and bandwidth, determining Receiving mapping information a bandwidth of a transmission window based on the mapping information and a distance between the user equipment device and the network apparatus, identifying whether at the bandwidth a subcarrier is an available subcarrier or a virtual subcarrier which fails to support reliable symbol transmission, estimating channel information at the bandwidth in one or more window available subcarriers, and transmitting, to the network apparatus, aware information of the user equipment device, the aware information comprising the channel information, positioning and ephemeris information, and subarray index of the user equipment device. Related communication apparatuses and computer readable media are also disclosed.

Abstract: Example embodiments of the present disclosure relate to methods, devices apparatuses and computer readable storage media of an access procedure for Cell-free Multi-input Multi-output (MIMO). In example embodiments, a terminal device transmits an access request to a first set of uplink access network devices. The access request contains a list of identifications of candidate downlink access network devices. Then, the terminal device receives an access response from a first set of downlink access network devices.

Abstract: Embodiments of the present disclosure relate to methods, devices and computer readable storage media of communication. A network device transmits, to a terminal device, channel state information reference signals associated with first number of ports at the network device; receives, from the terminal device, compressed channel state information generated based on capability of the terminal device; and recoveries, from the compressed channel state information, channel state information associated with second number of ports at the network device, the second number of ports being not less than the first number of ports.

Abstract: Example embodiments of the present disclosure relate to machine learning-based channel estimation. According to an example embodiment, a first device determines a signal quality that is expected in transmission of a reference signal from a second device to the first device and receives the reference signal from the second device. The first device selects, based on the expected signal quality, a channel estimation model from a plurality of channel estimation models that have been trained for a plurality of candidate signal qualities for the reference signal. The first device determines, using the selected channel estimation model and based on the received reference signal, channel state information of a communication channel from the first device to the second device. According to this solution, a channel estimation model is dynamically selected for use, depending on a real-time signal quality expected to be gained in transmission of a certain RS.

Abstract: Embodiments of the present disclosure relate to hybrid beamforming. A plurality of time delay elements is used to perform analog beamforming. Each time delay element is configured to apply the same time delay at different frequencies. The plurality of time delay elements is coupled to at least one RF chain to receive signals. Each antenna in an antenna array is configured to be selectively connected to one of the plurality of time delay elements based on a target configuration of a connection between the plurality of time delay elements and the antenna array. In operation, the target configuration is determined based on time delay information concerning the plurality of time delay elements and channel information concerning a physical channel over which the signals are to be transmitted.

Abstract: Embodiments of the present disclosure relate to a beamforming solution for FDD MIMO communication. A first device receives a reference signal from a second device in a first channel, and determines a covariance matrix associated with the first channel. The first device determines a set of beamforming vectors from the covariance matrix based on the number of dominant angles of arrival associated with the reference signal and the number of beams associated with the set of beamforming vectors, and performs a transmission to the second device based on the set of beamforming vectors in a second channel. In this way, beamforming vectors can be calculated from the transformed channel covariance matrix with the angular spread and imperfect reciprocity considered.

Abstract: Embodiments of the present disclosure relate to methods, apparatuses and computer readable storage media for SRS data transmission. In example embodiments, a method is provided. According to the method, an apparatus forwards, during a first period, first SRS data received from a terminal device to a further apparatus. The further apparatus determines, based on the first SRS data, compression information for compressing SRS data, and transmits the compression information to the apparatus. Thereby, the apparatus compresses, during a second period, second SRS data received from the terminal device based on the compression information, and transmits, during the second period, the compressed second SRS data to the further apparatus. In this way, the SRS data can be effectively compressed, thus reducing the latency of the SRS data transmission.

Abstract: Example embodiments of the present disclosure relate to monitoring a data processing model for channel information recovery. According to embodiments of the present disclosure, a solution for monitoring a data processing model for channel information is proposed. Two parallel measures by the data processing model for both the uplink and the downlink channels are used to determine whether the data processing model is available. In this way, it does not require extra feedbacks, which significantly reduces the overhead in the communication system and the computation efforts.

Abstract: Example embodiments of the present disclosure relate to applying uplink channel information to determine data processing model deployed for downlink use. According to embodiments, a solution for channel information reporting for applying uplink channel information to determine data processing model deployed for downlink use has been proposed. A data processing model is determined using uplink dataset (for example, uplink reference signal), then the data processing model is used to process downlink CSI. In this way, compared with high-resolution CSI feedback for training, it is more accurate and does not require extra CSI feedback, which significantly reduces the overhead. It also alleviates implementation efforts on the terminal device side, since no complicated CSI processing is required.

Abstract: Example embodiments of the present disclosure relate to compensating reference signals to train a neural network. According to embodiments of the present disclosure, a solution for compensating reference signals to train a neural network is proposed. A second device transmits information to a first device. The information is used to trigger generation and transmission of compensated training reference signals. The information indicates a set of receiving ports at the first device. The first device compensates the training reference signals based on downlink channel information and transmits the compensated signals to the second device via one or more transmitting ports. In this way, CSI can be obtained more accurately. Further, a processing model at the second device can be improved.

Abstract: Embodiments of the present disclosure relate to methods, devices and computer readable storage media of communication. A network device transmits, to a terminal device, channel state information reference signals associated with first number of ports at the network device; receives, from the terminal device, compressed channel state information generated based on capability of the terminal device; and recoveries, from the compressed channel state information, channel state information associated with second number of ports at the network device, the second number of ports being not less than the first number of ports.

Abstract: Systems, methods, apparatuses, and computer program products for non-linear precoding are provided. One method may include combining, by a network node, of linear and non-linear precoding, for example based on specific channel state information acquisition from at least one user equipment, and generating two types of demodulation reference signals for the concatenated linear and non-linear precoding. The method may include multiplexing, by the network node, the two types of demodulation reference signals with data. A first of the two types of demodulation reference signals may be linearly precoded with one linear precoding matrix from a first-stage linear precoder, and another one of the two types may be linearly precoded with both the first-stage linear precoder and a feedforward filter in a second-stage non-linear precoder from the concatenation of linear and nonlinear precoders.

Abstract: Example embodiments of the present disclosure relate to machine learning-based channel estimation. According to an example embodiment, a first device determines a signal quality that is expected in transmission of a reference signal from a second device to the first device and receives the reference signal from the second device. The first device selects, based on the expected signal quality, a channel estimation model from a plurality of channel estimation models that have been trained for a plurality of candidate signal qualities for the reference signal. The first device determines, using the selected channel estimation model and based on the received reference signal, channel state information of a communication channel from the first device to the second device. According to this solution, a channel estimation model is dynamically selected for use, depending on a real-time signal quality expected to be gained in transmission of a certain RS.

Abstract: Disclosed are methods and apparatuses for performing precoding. A method disclosed comprises steps of: transmitting a CSI reference signal to a UE to request the UE to report status-related information of respective panels; acquiring, based on first feedback information from the UE, the status-related information of the respective panels whose status-related information has been measured by the UE and a serving panel selected by the UE; and performing, based on the status-related information of the respective panels and the serving panel selected by the UE, two-stage beamforming separately to the respective panels, so as to first perform decoupling to suppress inter-panel interference and then perform per-panel precoding. The disclosure offers the following advantages: effectively eliminating the inter-panel and intra-panel interference, avoiding complex inter-panel calibration, and reducing implementation complexity and CSI feedback overhead.

Abstract: Systems, methods, apparatuses, and computer program products for non-linear precoding in radio access networks are provided. One method may include, when it is determined that a user equipment is capable of being non-linearly precoded, determining one of two non-linear precoding modes and indicating the determined non-linear precoding mode to the user equipment. One of the two non-linear precoding modes is configured to use explicit beamformed channel state information, and the other one of the two non-linear precoding modes is configured to use explicit full downlink channel state information.

Abstract: Systems, methods, apparatuses, and computer program products for non-linear precoding in radio access networks are provided. One method may include, when it is determined that a user equipment is capable of being non-linearly precoded, determining one of two non-linear precoding modes and indicating the determined non-linear precoding mode to the user equipment. One of the two non-linear precoding modes is configured to use explicit beamformed channel state information, and the other one of the two non-linear precoding modes is configured to use explicit full downlink channel state information.