A method of allocating reference signals for determining radio link quality, in a source node, the method triggering or comprising the steps of: Transmitting to a candidate node information about at least one reference signal allocated for transmission in at least one beam controlled by the source node and/or information about one or more reference signals eligible to be allocated for a transmission in at least one beam controlled by the candidate node.

A first communication device transmits a plurality of training signals to a second communication device via a communication channel. The first communication device receives feedback generated at the second communication device based on the plurality of training signals. The feedback includes steering matrix information for a plurality of orthogonal frequency division multiplexing (OFDM) tones and (ii) additional phase information corresponding to channel estimates obtained for the plurality of OFDM tone. The first communication device constructs, based on the steering matrix information, a plurality of steering matrices corresponding to the plurality of OFDM tones, and compensates, using the additional phase information, the plurality of steering matrices to reduce phase discontinuities between the OFDM tones. The first communication device steers, using the compensated steering matrices, at least one transmission via the communication channel to the second communication device.

The disclosure relates to a communication technique for convergence of an IoT technology and a 5G communication system for supporting a higher data transmission rate beyond a 4G system, and a system therefor. The disclosure can be applied to an intelligent service (for example, a smart home, a smart building, a smart city, a smart cart or connected car, health care, digital education, retail business, security and safety-related service, etc.) on the basis of a 5G communication technology and an IoT-related technology. The disclosure defines a mobility method for a terminal residing in a system in which transmission/reception points (TPRs), supporting solely some protocols among entire access stratum protocols comprising PHY, MAC, RLC, PDCP, and RRC, coexist in a wireless communication system. Specifically, the disclosure defines a method for dynamically changing, depending on determination by a base station, a beam and a transmission/reception point to be used for transmitting information to or receiving information from a terminal through a method in which a system using multiple beams notifies, in advance, of a measurement reference signal transmitted using transmission/reception points of different networks, to allow a terminal to select a required reception beam from a corresponding resource and measure beam information of each transmission/reception point, or a terminal transmits measured information as feedback in which each transmission/reception point is specified. Accordingly, the disclosure can provide a criterion of rapid and highly precise determination for changing a beam and a transmission/reception point and thus prevent a terminal from needlessly measuring and reporting, so as to achieve an effect of reduction in the power consumption of the terminal and reduction of delay in change of a transmission/reception point.

The specification and drawings present methods and apparatuses for feedback signaling for beamforming purposes in a multiple input-multiple output (MIMO) radio environment. According to an embodiment of the invention, a mobile device is configured to measure an integer number P of different beam groups, each group representing one or more transmit beams and each group corresponding to one or more antenna ports at the mobile device. The mobile device is triggered according to the configuration to provide feedback. The radio access node transmits reference signals on each of the transmit beams across all of the groups for measurement by the mobile device and receives the triggered feedback including, for each of the different beam groups, at least one best match between a transmit beam of the respective group and a corresponding antenna port and an indication of measurement results for the best match.

A method for reporting an optimal beam includes: a MSG3 is sent to a base station on a measured optimal beam; and a MSG4 returned by the base station is waited to be received on both the optimal beam and an initial beam originally configured to send the MSG3. As the MSG3 is sent to the base station on a measured optimal beam, the optimal beam can be reported implicitly in the random-access process; and as no bit for representing beam information needs to be additionally defined, resources can be saved.

Device, methods and systems for precoding in wireless systems using orthogonal time frequency space multiplexing are described. An exemplary method for transmitting wireless signals includes mapping data to generate a quadrature amplitude modulation (QAM) signal in a delay Doppler domain, determining a perturbation signal to minimize expected interference and noise, perturbing the QAM signal with the perturbation signal, thereby producing a perturbed signal, generating a pre-coded signal by pre-coding, using a linear pre-coder, the perturbed signal, and transmitting the pre-coded signal using an orthogonal time frequency space modulation signal scheme.

Systems and methods for Channel State Information (CSI) feedback on small control channels are provided. In some embodiments, a method of operation of a second node connected to a first node in a wireless communication network includes reporting CSI feedback to the first node on a physical channel. In some embodiments, this is accomplished by identifying a subset of codebook entries from an advanced CSI codebook of coefficients; selecting a codebook entry from the subset of codebook entries; and reporting an index of the selected codebook entry from the subset of codebook entries. This may allow robust feedback and allow variably sized cophasing and beam index indicators to be carried on the channel. Also, this may allow periodic feedback of advanced CSI on existing Physical Uplink Control Channel (PUCCH) Format 2.

A method and apparatus for timing advance (TA) synchronization for uplink (UL) data transmissions are provided. A base station transmits a TA instruction to a UE. The TA instruction indicates one of at least two TA options. The first TA option indicates direct initial grant-free (GF) uplink (UL) data transmissions. The second TA option indicates indirect initial GF UL data transmissions with the UE initiating TA reference signaling for updating a TA parameter of the UE. The UE performs an initial GF UL data transmission to the base station based on the TA instruction.

This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for null data packet (NDP) based implicit sounding and calibration for a wireless local area network (WLAN). An AP may perform a calibration procedure with one or more stations (STAs) that involves NDP transmissions. The AP may calibrate an effective downlink channel response to an effective uplink channel to compensate for transmit and receive chain differences. The AP may initiate implicit sounding by transmitting a downlink message that includes an uplink NDP announcement frame to the one or more STAs, prompting uplink multi-user (MU) NDP transmission. The AP may estimate the uplink channel based on measuring the received NDPs and mirror the estimated uplink channel for reciprocal downlink channel estimation and precoding generation. The AP may perform MU multiple input multiple output (MIMO) downlink transmission that is precoded based on the channel estimation.

An antenna displacement correction method for an OAM multiplexing communication system includes: a step of estimating a displacement amount by evaluating an evaluation function defined such that a theoretical channel response between a transmitting antenna and a receiving antenna matches a measured channel response estimated in a receiving station by using a known signal transmitted from a transmitting station, wherein the theoretical channel response has, as a parameter, the displacement amount indicating an amount of displacement of a reference axis predefined for each of the transmitting antenna and the receiving antenna from a predetermined position with respect to a desired relative positional relationship between the transmitting antenna and the receiving antenna; and a step of correcting a displacement of each of the transmitting antenna and the receiving antenna according to the estimated displacement amount.