For example, an apparatus may include a Printed Circuit Board (PCB); a Multiple-Input-Multiple-Output (MIMO) radar antenna on the PCB, the MIMO radar antenna comprising a plurality of Transmit (Tx) antenna elements configured to transmit Tx radar signals, and a plurality of receive (Rx) antenna elements configured to receive Rx radar signals based on the Tx radar signals; and a surface wave mitigator connected to the PCB, the surface wave mitigator configured to mitigate an impact of surface waves via the PCB on a radiation pattern of the MIMO radar antenna.

Channel state information (CSI) feedback in a wireless communication system is disclosed. A precoding matrix is generated for multi-antenna transmission based on precoding matrix indicator (PMI) feedback, wherein the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first codebook and a second codebook. In one embodiment, the first codebook comprises at least a first precoding matrix constructed with a first group of adjacent Discrete-Fourier-Transform (DFT) vectors. In another embodiment, the first codebook comprises at least a second precoding matrix constructed with a second group of uniformly distributed non-adjacent DFT vectors. In yet another embodiment, the first codebook comprises at least a first precoding matrix and a second precoding matrix, where said first precoding matrix is constructed with a first group of adjacent DFT vectors, and said second precoding matrix is constructed with a second group of uniformly distributed non-adjacent DFT vectors.

A wireless device may support a plurality of channel state information (CSI) processes. The wireless device may send an indication of a number of supported CSI processes to a first base station. The first base station may send to the wireless device a handover command, instructing the wireless device to handover to a second base station. The handover command may comprise configuration parameters for CSI processes associated with the second base station. The configuration parameters may be based on the number of CSI processes supported by the wireless device.

An Open Radio Access Network Category B radio unit (0-RU) of a wireless network associates, for a first extended antenna carrier identifier (eAxC_Id) corresponding to a layer 0 precoding layer identifier (layerID), the first eAxC_Id with one or more second eAxC_Ids. Each second eAxC_Id corresponds to a non-layer 0 precoding layerID. The O-RU receives, for a user equipment (UE), a control plane message of Section Type 1 or 3. The message includes an extension type (ExtType) 3 first data layer, along with the first eAxC_Id in a transport header. The ExtType 3 first data layer indicates a number of precoding layers. The O-RU then precodes user plane data for downlink physical resource blocks allocated to the UE using the layer 0 precoding layerID of the first eAxC_Id, and each associated non-layer 0 precoding layerID of the one more second eAxC_Ids required to complete the number of precoding layers.

Methods, apparatuses, and computer readable media for tone plans and preambles for extremely high throughput (EHT) in a wireless network are disclosed. An apparatus of an EHT access point (AP) or EHT station (STA), where the apparatus includes processing circuitry configured to: encode a physical layer (PHY) protocol data unit (PPDU), the PPDU including a EHT preamble, the EHT preamble including a legacy preamble portion and a EHT preamble portion, the legacy preamble including a legacy short training field (L-SFT), a legacy long-training field (L-LTF), and a legacy signal field (L-SIG), the EHT preamble portion comprising an EHT short signal field (EHT S-SIG), the EHT S-SIG including a modulation and coding scheme (MCS) subfield indicating a MCS of a subsequent data portion. The PPDU may be transmitted on a distributed or contiguous resource unit (RU) allocation. The RU may be configured to not straddle two physical 20 MHz subchannels.

Systems and methods are provided for dynamically modifying beamforming weights based on MU-MIMO user device pairings. A quantity of MU-MIMO user device pairings served by a node is determined. Based on a maximum quantity of potential MU-MIMO user device pairings for the node, it is determined that a quantity of the MU-MIMO user device pairings for the node is below a threshold. Because the quantity of the MU-MIMO user device pairings is below the threshold, beamforming weights are modified to widen a vertical main lobe to increase the quantity of MU-MIMO user device pairings.

Methods and apparatus are provided for transmitting a symbol from a plurality of antennas. In one example, a method comprises transmitting simultaneously, from each antenna, the symbol multiplied by a respective element of a selected column of a matrix. The number of rows of the matrix is at least the number of antennas, the number of columns of the matrix is at least 9, and the matrix comprises or is a sub-matrix of a real Hadamard matrix of maximum excess.

A method performed by a network node (10) for finding a direction to a wireless device (20) in a wireless communication network is provided. The method comprises the step (S1) of the network node transmitting reference signal pairs on at least one pair of correlated antennas. Each reference signal pair has a unique phase difference between the signals in the signal pair, and the unique phase differences of the reference signal pairs are distributed over a given angular interval. The method further comprises the step (S2) of the network node receiving from the wireless device, in response to each pair of reference signals, a respective indication of a preferred pre-coding matrix, and the step (S3) of the network node determining a direction to the wireless device based on the received indications, information representative of the phase differences of the reference signal pairs, and phase information related to the indicated preferred pre-coding matrices.

This invention presents methods for estimating MU-MIMO channel information using SU-MIMO channel information to choose a modulation and channel coding appropriate for the quality of the MU-MIMO channels, for adaptively selecting MU-MIMO precoding methods based on estimations of a plural of UEs and for compensating hardware impairments in MU-MIMO precoding.

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.