Beam acquisition method and communication device

Abstract

At a first communication device in a wireless communication network, reference signaling is received from a second communication device in two or more beams having the same direction, and one or more values associated with a direction from the first communication device to the second communication device for receiving the reference signaling are determined. The one or more values are determined from the received reference signaling. The direction has a higher accuracy than an accuracy of a beamwidth associated with the received reference signaling. The direction can be or include, for example, an angle of arrival or an angle of departure, and in the case of an angle of departure, signaling indicating the one or more values is transmitted by the first communication device to the second communication device or another component, such as a network device.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to U.S. Patent Application No. 16 / 739,760, filed January 10, 2020, entitled “Beam Acquisition Methods and Communication Devices,” the contents of which are incorporated herein by reference as if reproduced in their entirety. Technical Field

[0003] This application generally relates to wireless communication, and more specifically to beam acquisition in wireless communication networks. Background Technology

[0004] Wireless communication in the millimeter wave (mmWave) / Terahertz (THz) band (100 GHz to 300 GHz) has been identified as a potential medium for further enhancing the connectivity offered by fifth-generation (5G) communication systems. Compared to lower frequency bands (<100 GHz), THz transmission channels have a larger bandwidth (BW), higher scattering and reflection losses (sparser channels), and higher path loss. One potential solution to address high path loss involves ultra-massive multiple-input multiple-output (UM-MIMO) systems, which are easily implemented through an array-of-subarrays (AoSA) structure. In this type of structure, antenna panels in multiple subarrays comprise numerous antenna elements connected to one or more radio frequency (RF) chains, which can provide high beamforming gain for narrow beams by using a hybrid of analog and digital beamforming at the transmitter and receiver. For such narrow beams, beam acquisition can be challenging because it requires accurate estimation of the channel angle of arrival (AoA) and angle of departure (AoD). Summary of the Invention

[0005] This application partially relates to a fast and efficient AoA / AoD estimation algorithm that takes into account the characteristics of THz channels (specifically, sparsity, large BW, and high path loss). It also considers the impact on signaling in uplink (UL) and downlink (DL) transmissions.

[0006] According to one aspect of this application, there is a method comprising: receiving reference signaling from a second communication device in a wireless communication network at a first communication device in the wireless communication network, in two or more beams having the same direction; and determining a value associated with the direction in which the first communication device receives the reference signaling from the second communication device. The value is determined based on the received reference signaling. The accuracy of the direction is higher than the accuracy of the beamwidth associated with the received reference signaling.

[0007] Another aspect of this application relates to a non-transient processor-readable medium storing instructions that, when executed by one or more processors on a first communication device in a wireless communication network, cause the one or more processors to perform a method. In one embodiment, the method includes: at the first communication device, receiving reference signaling from a second communication device in the wireless communication network in two or more beams having the same direction; and, based on the received reference signaling, determining a value associated with the direction in which the first communication device receives the reference signaling from the second communication device, the accuracy of the direction being higher than the accuracy of the beamwidth associated with the received reference signaling.

[0008] A first communication device according to another aspect of this application includes: a receiver for receiving reference signaling from a second communication device in the wireless communication network in two or more beams having the same direction; and a processor coupled to the receiver for determining, based on the received reference signaling, a value associated with the direction in which the first communication device receives the reference signaling from the second communication device. The accuracy of the direction is higher than the accuracy of the beamwidth associated with the received reference signaling.

[0009] A method according to another aspect of this application includes: transmitting reference signaling from a second communication device to a first communication device in two or more beams having the same direction; receiving signaling at the second communication device, the signaling indicating a value determined by the first communication device and associated with a direction. The direction is the transmission direction of the reference signaling, from which the first communication device receives the reference signaling, and the accuracy of the direction is higher than the accuracy of the beamwidth associated with the reference signaling.

[0010] This method can be implemented as instructions for execution by one or more processors. For example, a non-transitory processor-readable medium can store instructions that, when executed by one or more processors on a second communication device in a wireless communication network, cause the processors to perform a method comprising: transmitting reference signaling to a first communication device in the wireless communication network in two or more beams having the same direction; the second communication device receiving signaling indicating a value determined by the first communication device and associated with the transmission direction of the reference signaling, from which the first communication device receives the reference signaling. The accuracy of the direction is higher than the accuracy of the beamwidth associated with the reference signaling.

[0011] This application also relates in part to a communication device for a wireless communication network, wherein the communication device includes: a transmitter for transmitting reference signaling to a first communication device in the wireless communication network on two or more beams having the same direction; and a receiver for receiving signaling indicating a value determined by the first communication device and associated with a transmission direction of the reference signaling from the communication device, the first communication device receiving the reference signaling from the transmission direction, the accuracy of which is higher than the accuracy of the beamwidth associated with the reference signaling.

[0012] Other aspects and features of the embodiments of this application will become clear to those skilled in the art after reviewing the following description. Attached Figure Description

[0013] Embodiments of this application will now be described with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a block diagram illustrating an exemplary AoSA antenna system;

[0015] Figure 2 This is a block diagram illustrating an exemplary antenna array;

[0016] Figure 3 The diagram shows the simulation results, illustrating the mean square error (MSE) of the estimated direction versus the received pilot energy-to-noise ratio.

[0017] Figure 4 This is a graph showing the further simulation results, illustrating the estimated direction and ratio. Figure 3 The MSE of the lower received pilot energy-to-noise ratio;

[0018] Figure 5 This is a graph illustrating the autocorrelation function of a maximum length (ML) pseudo-noise (PN) sequence;

[0019] Figure 6 This is a graph showing the simulation results in the form of normalized signal-to-noise ratio (SNR) and AoA with and without beam deflection effects;

[0020] Figure 7 This is a graph showing the simulation results in the form of the normalized SNR ratio versus AoA;

[0021] Figure 8 This is a graph showing the simulation results in the form of the estimated angles MSE and AoA;

[0022] Figure 9A This is a signal flow diagram illustrating a signaling implementation based on an embodiment involving downlink (DL) measurements;

[0023] Figure 9B This is a signal flow diagram illustrating signaling based on another embodiment involving DL-based measurement and estimation;

[0024] Figure 10A This is a signal flow diagram illustrating signaling according to an embodiment involving uplink (UL) based measurements;

[0025] Figure 10B This is a signal flow diagram illustrating signaling based on another embodiment involving UL-based measurement and estimation;

[0026] Figure 11A This is a signal flow diagram illustrating an embodiment of signaling based on measurements and estimations involving sidelinks (SLs);

[0027] Figure 11B This is a signal flow diagram illustrating the signaling according to an embodiment involving SL-based measurements;

[0028] Figure 11C This is a signal flow diagram illustrating signaling based on another embodiment involving SL-based measurement and estimation;

[0029] Figure 11D This is a signal flow diagram illustrating signaling according to yet another embodiment involving SL-based measurement and estimation;

[0030] Figure 12 This is a signal flow graph illustrating signaling based on another embodiment of SL-based measurement and estimation involving channel reciprocity;

[0031] Figure 13 This is a flowchart illustrating an exemplary method according to an embodiment;

[0032] Figure 14This is a flowchart illustrating an exemplary method according to an embodiment;

[0033] Figure 15 An exemplary communication system that can implement embodiments of this application is shown;

[0034] Figure 16A This is a block diagram of an exemplary electronic device;

[0035] Figure 16B This is a block diagram of an exemplary base station;

[0036] Figure 17 This is a block diagram of the component module. Detailed Implementation

[0037] For the purpose of illustration, specific exemplary embodiments are explained in detail below with reference to the accompanying drawings.

[0038] The embodiments described herein present information sufficient to practice the claimed subject matter and illustrate methods for practicing such subject matter. Upon reading the following description in conjunction with the accompanying drawings, those skilled in the art will understand the concept of the claimed subject matter and will recognize that the application of these concepts is not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of this application and the appended claims.

[0039] Furthermore, it should be understood that any module, component, or device with executable instructions disclosed herein may include or otherwise access one or more non-transitory computer / processor-readable storage media to store information, such as computer / processor-readable instructions, data structures, program modules, and / or other data. A non-exhaustive list of examples of non-transitory computer / processor-readable storage media includes: magnetic tape cassettes, magnetic tape, disk storage devices or other magnetic storage devices; optical discs, such as compact disc read-only memory (CD-ROM), digital video discs or digital versatile discs (DVDs), and Blu-ray discs. TMOr other optical storage media; volatile and non-volatile, removable and non-removable media implemented in any method or technology, including random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other storage technologies. Any such non-transitory computer / processor storage medium may be part of a device or may be accessed or connected to a device. Computer / processor-readable / executable instructions for implementing the applications or modules described herein may be stored or otherwise preserved by such non-transitory computer / processor-readable storage media.

[0040] Several techniques have been proposed for beam acquisition in MIMO systems, including beam scanning-based and compressed sensing-based techniques. While compressed sensing-based techniques may have lower overhead than beam scanning-based techniques, they often have high computational requirements due to iterative processing such as orthogonal matching pursuit (OMP). Therefore, a beam scanning technique with lower overhead and computational requirements is generally needed.

[0041] Considering the narrow beams in the THz band as described above, conventional beam searching or scanning of all possible narrow beams results in high overhead. The overhead is proportional to the number of beams scanned on the transmitter and receiver. Hierarchical beamforming can be deployed to reduce overhead by performing multi-level beam scanning and progressive beam refinement, where beam scanning begins by acquiring a coarse transmit (Tx) and receive (Rx) beam pair, and then performing a beam scan within the coarse (wider) beam to acquire a finer (narrower) and more precise beam in the AoA / AoD direction.

[0042] While hierarchical beamforming can reduce the overhead associated with conventional beam searching, further overhead reduction is important for very narrow beams. Several techniques have been proposed to directly estimate the AoA / AoD of wide beams, rather than performing another stage of beam scanning within the wide beam. Specifically, monopulse radar techniques can be used to estimate the AoA / AoD of two wide beams by amplitude comparison, phase comparison, or cross-correlation between the received signals in the two beams or antennas. In amplitude comparison, AoA is estimated using the received power of the two antennas or two sets of antennas, where the beams are tilted but overlap. However, in phase comparison, AoA is estimated using the phase difference between the received signals from the two antennas or two sets of antennas, where the beams point in the same direction. In beams with the same orientation, cross-correlation techniques can transform AoA estimation into an estimate of the frequency of the cross-correlation function of the received signals in the two beams.

[0043] Although amplitude comparison techniques have been applied to MIMO systems, phase comparison and cross-correlation techniques require further adaptation and development for different transmitters and receivers used for AoA and AoD estimation and tracking. Therefore, it is important to focus on applying these techniques to wireless communication in THz MIMO systems, taking into account the following characteristics and challenges: (1) determining the AoA and AoD of a signal as it propagates from the transmitter to the receiver or is reflected by an object between the transmitter and receiver; (2) the high temporal resolution of THz channel models and the limited number of distinguishable paths; (3) the potential for phase ambiguity when the phase difference between different subarrays is greater than 2π; and (4) the spatial broadband effect of AoSA MIMO structures, even within different antenna elements in the same subarray.

[0044] In MIMO systems, due to the spatial broadband effect, different antennas receive signals at different times, unlike narrowband (NB) systems where signals arrive at all antennas almost simultaneously. This effect occurs when the transmission bandwidth (BW) is large and comparable to the carrier frequency. In this case, the symbol (pulse) duration is very short and comparable to the arrival delay of different antennas. Due to this delay, inter-symbol interference (ISI) occurs, and in multi-carrier transmission, signals on different subcarriers appear to arrive from different directions. This is known as "beam skew."

[0045] While ISI reduces beamforming gain, it is important to consider utilizing the spatial broadband effect when estimating AoA and / or AoD, as the delay between the antenna and the ISI level depends on the AoA. Although this may appear similar to the relationship used for AoA estimation in holographic radar, radar technology does not consider the actual AoSA structure where multiple antennas are connected to a single receiver (e.g., an RF chain). Furthermore, since radar transmits and receives “pilot” signals, it has a time reference signal for comparing the received signals. Moreover, holographic radar considers the transmission and reception of a single antenna, not an antenna array, at any given time. Therefore, it is important to investigate an efficient way to utilize the spatial broadband effect for AoA estimation of AoSA structures in the THz band.

[0046] In some embodiments, this application provides beamforming techniques suitable for, for example, the THz band, for fast and efficient beamforming estimation considering any one or more of the following factors: (1) sparse channels, (2) high path loss, (3) spatial broadband effects, and (4) hybrid modulus beamforming with an AoSA structure. The impact on signaling is also considered.

[0047] The disclosed embodiments include several beamforming techniques, as illustrative and non-limiting examples, for calculating or otherwise determining AoA / AoD by utilizing any one or more of the following: (1) higher temporal resolution for separating different paths of the channel; (2) cross-correlation of received signals on different RF chains (i.e., individual AoSA structures) connected to different antenna groups having the same beam pattern; and (3) spatial broadband effects based on the transmission delay between adjacent antennas associated with AoD or the reception delay between adjacent antennas associated with AoA. It should be noted that while the analysis presented herein by way of example considers individual AoSA structures, it can be extended to overlapping AoSA structures, wherein a set of antennas connected to each RF chain completely or partially overlaps with another set of antennas connected to another RF chain. For example, in some embodiments, antennas may be connected to multiple RF chains.

[0048] Channels at THz are sparser than those at lower frequencies, with only a few paths between the transmitter and receiver. High path loss tends to confine paths to short distances, primarily line-of-sight paths, with relatively few reflections from nearby reflectors. In this high path loss environment, the use of beamforming with a large number of antennas is preferred, relying more on analog beamforming and less on digital beamforming. The relatively large bandwidth available at THz (e.g., on the order of several GHz) allows for very high time resolution. The resulting channel is a sparse channel with distinguishable paths, and due to the high bandwidth, beam skew may occur, with signals arriving at or leaving the receiver antenna element at different timings. These characteristics make the disclosed embodiments particularly suitable for THz applications, but other applications or deployments are possible.

[0049] In some embodiments, the beam orientation is estimated based on measurements of the phase difference between reference signaling received in two or more beams having the same orientation. Very accurate beam orientation can be estimated from a wider beam, eliminating the need for further hierarchical beam scanning beyond using a wide beam. It should be noted that phase ambiguity may exist in this type of estimation due to 2π phase winding. The effects on the signaling may include: signaling to the receiver indicating the beam setup to be used for beam scanning at the transmitter; mapping the beam so that the receiver can estimate the beam orientation; and feeding back the estimated beam orientation to the transmitter. Another embodiment involves configuring reference signaling, such as channel state information reference signal (CSI-RS) signaling, for the receiver to calculate or otherwise determine the internal phase between different CSI-RS signaling pairs received corresponding to different beams, and to report the measured phase difference between these different beams.

[0050] Implementations may involve narrowing down the estimate of beam orientation by observing the level of beam skew. Beam skew can occur within antenna elements connected to multiple RF chains and between antenna elements connected to multiple RF chains. By comparing beam skew in different RF chains, the beam orientation can be estimated at least with coarse resolution. Signaling effects may include signaling to the receiver to indicate antenna configuration and beam setup to narrow down the range of estimated beam orientation. For example, this can help mitigate potential ambiguity caused by phase entanglement. Another option involves signaling to indicate the configuration of reference signaling (e.g., CSI-RS signaling) and instructing the receiver to compare beam skew and report one or more measurements or comparisons to the transmitter for beam orientation estimation.

[0051] In some embodiments, time and beam resolution are used to achieve extreme sparsity for one path per beam scan at each time scale.

[0052] This document considers each of these embodiments and other embodiments.

[0053] Consider an embodiment involving the use of beam scanning and temporal resolution to separate paths. In a THz deployment model, the following observations can be made: when a large beamwidth is assigned, smaller time differences are observed due to the high temporal resolution, and different beams travel different paths due to the high beam resolution. Therefore, it is unlikely that more than one path will arrive or depart at the same angle within the beam resolution or within the same flight time within the temporal resolution. For example, at a 1 GHz beamwidth, even short flight distances of less than 1 m are distinguishable. This follows the uncertainty principle and the Nyquist sampling rate, where, at a 1 GHz beamwidth, the temporal resolution is on the order of 1 nanosecond (ns), equivalent to an electromagnetic wave propagation distance of 30 cm.

[0054] For path separation, in one embodiment, a wideband pilot PN sequence with a relatively narrow transmit beam repeating and exhibiting very good autocorrelation characteristics is proposed. A "good" cross-correlation characteristic means that the cross-correlation between two different PN sequences is 0 or close to 0. A "good" autocorrelation characteristic means that when there is no delay (delay = 0), the autocorrelation between the PN sequence and its delayed version is 1 or close to 1, while when the delay between the PN sequence and its delayed version is sufficient, for example, when the delay is equal to or greater than the chip duration of the PN sequence, the autocorrelation between the PN sequence and its delayed version is 0 or close to 0.

[0055] At the receiver, scanning can be performed on a relatively narrow receiving beam, and the beam can be separated using time and beam resolution. In most cases, this is expected to result in a sparse order with at most one non-zero element. For cases where multiple paths occur within the same beam and the same flight time, which are unlikely, a narrower beam can be used to separate these paths if they are not diffracted or reflected from the same object.

[0056] When a line-of-sight (LoS) path exists, the direction of the LoS path is typically the direction of interest, and this direction can be determined by focusing on the shortest time of flight and one or more beam directions associated with the shortest time of flight. THz deployments may be particularly well-suited for this type of estimation because separation of the shortest time of flight may be infeasible without a large beamwidth.

[0057] In the mmWave scheme, channel coefficients are detected using a sparse model of the tracking channel and some compressed sensing algorithms. However, by using temporal separation of the channel coefficients as proposed in this paper, the sparsity order is reduced to 1 in some embodiments, thus allowing direct solution of the channel coefficients.

[0058] Now consider embodiments involving the estimation of AoA and AoD using phase difference. In these embodiments, channel coefficients are estimated based on the AoA and AoD of the relevant path l, where l∈{1,2,…,L}, and L is the number of distinguishable paths in the channel. This is discussed below by way of example for estimating AoA.

[0059] Figure 1 This is a block diagram illustrating an exemplary AoSA antenna system. For example, exemplary antenna system 100 may include at least two sets of antenna elements, and the example shown includes four sets of antenna elements 102, 104, 106, and 108. Each set of antenna elements includes one or more antenna elements, and each antenna element is connected to an RF chain. The RF chain is not in... Figure 1 To avoid making the diagram more crowded, the following is shown. For the purposes of this example, it is assumed that all RF chains use the same antenna beam pattern, and four beams with the same beam pattern are shown as 112, 114, 116, and 118. More generally, at least two beams can be used. The at least two beams can have the same direction. Any of various types of antenna elements and RF chain implementations can be used, and the embodiments disclosed herein are not limited to any particular implementation. In some examples, typically, the RF chain includes any suitable structure for generating signals for wireless transmission or processing signals for wireless reception. In the example shown, each group of antenna elements is distributed within a square area of ​​size D×D.

[0060] During beam scanning, each RF chain scans the antenna beams 112, 114, 116, and 118 in different directions relative to the XZ plane. Signals arrive at antenna elements 102, 104, 106, and 108 from directions within the beam pattern, as shown in 120.

[0061] The phase difference between different RF chains is a function of beam tilt and RF chain separation (in terms of separation between groups of antenna elements coupled to the RF chain). In the example shown, the received signal of channel path l has two tilt angles, including one tilt angle relative to the x-axis, denoted as ζ. rl An angle of inclination relative to the z-axis, denoted as φ. rl α rz α represents the phase difference of the received signal between the top antenna subarrays 102 and 104 and the bottom antenna subarrays 108 and 106 aligned with them below in the z-direction. rxThe phase difference between the received signals of the left antenna subarrays 102 and 108 and the right antenna subarray aligned with them in the x-direction can be expressed as follows:

[0062]

[0063] Among them, D is as follows Figure 1 As shown (the length of each subarray) and described above, λ is the wavelength. It should be noted that, due to... Figure 1 In the AoSA structure, the phase difference depends on D, where D also represents the distance between the centers (or corresponding antenna elements) of subarrays such as subarrays 102 and 104 (and subarrays 108 and 106) in the X direction, and the distance between the centers (or corresponding antenna elements) of subarrays such as subarrays 102 and 104 (and subarrays 108 and 106) in the Z direction. For other AoSA structures, the distances between different subarrays (serving the same beam direction) in the X and / or Z directions may be different.

[0064] α rz and α rx It can be calculated The phase is estimated, where y1(t) and y2(t) are the received signals coupled to two RF chains of different antenna subarrays (referred to as top and bottom antenna subarrays or left and right antenna subarrays) aligned in one direction. It is the conjugate of y2(t). Then, α can be used. rz and α rx The estimated value of φ rl and ζ rl It should be noted that, for Figure 1 In the example considered, α rz It is estimated that the subarrays associated with y1(t) and y2(t) can be 10² and 10⁸ (option 1) or 10⁴ and 10⁶ (option 2), respectively. Considering these two options, α can be estimated from one or both of them. rz When both options are used, multiple deployment methods are possible. For example, α rz It could be option 1, α. rz and option 2's α rz The average of options 1 and 2. Another example is taking the average of options 1 and 2. The sum, then α rz The phase is estimated as the sum. A similar process applies to α. rx .

[0065] For AoD estimation and Figure 1The exemplary antenna array in the example uses the following mechanism in the embodiment. Similarly, in this example, there are four sets of antenna elements 102, 104, 106, and 108, each set connected to an RF chain, and each RF chain scans its beam in different directions relative to the XZ plane. The four different RF chains used for transmission for AoD estimation employ at least three different PN sequences with good autocorrelation and cross-correlation properties. For channel path l, the signal exits antenna elements 102, 104, 106, and 108 from directions within the beam pattern. Therefore, φ tl and ζ tl Definition and φ rl and ζ rl Similar, but only for transmitting signals.

[0066] In this example, the receiver of the signal in channel path l estimates the phase of the channel through which the four PN sequences pass, so that the receiver can obtain four received signals from the four Tx RF chains. The phase difference between the different RF chains is a function of beam tilt and RF chain separation. For the phase difference and tilt angle defined above, but here for the transmission side, the phase difference α can be estimated. tz and α tx , where α tz It is the phase difference of the transmitted signal between the top antenna subarrays 102, 104 and the bottom antenna subarrays 108, 106, while α tx This refers to the phase difference of the received signals between the left antenna subarrays 102 and 108 and the right antenna subarrays 104 and 106. It should be noted that if the transmitter and receiver have... Figure 1 In the same AoSA antenna system, each Tx RF chain can transmit different PN sequences, allowing each Rx RF chain to separate signals arriving from different Tx RF chains. Then, considering the four received signals on each Rx RF chain, and estimating α from each option... rz There are two options, and eight options are available for α. rz Estimate. Therefore, one or more of these options can be used to estimate α. rz For example, when all these options are used, α rz Estimated as all 8 options The phase of the sum (as described above, the sum of the two options for each received signal). A similar case applies to α. rx α tz and α tx In this example, to determine the AoD, the phase difference is calculated at the receiver but will be used by the transmitter. Signaling is used to send information from the receiver to the transmitter to indicate the phase difference.

[0067] For example, the receiver can send an indication α to the transmitter.tz and α tx The signaling carrying this phase difference information can take any of various forms. Consider an example of user equipment (UE) performing measurements based on DL reference signaling. The phase difference determined by the UE can be sent back in uplink signaling via an uplink control channel (e.g., physical uplink control channel, PUCCH) or another channel (e.g., physical uplink shared channel, PUSCH). In UL measurement scenarios, the phase difference value can be sent to the UE by the base station or other network equipment via DL channels such as the physical downlink control channel (PDCCH), media access control (MAC) signaling, or other DL signaling.

[0068] If the receiver knows the beam characteristics and antenna subarray information, for example Figure 1 Given the value of AoD and the beam pattern used at the transmitter, the receiver can calculate AoD and report it to the transmitter. This involves signaling that reports the AoD value to the transmitter at least once. For example, in DL-based reference signaling, AoD reporting can be done via PUSCH, PUCCH, or other uplink channels. For instance, the receiver can learn about the transmitter's configuration via radio resource control (RRC) signaling. For UL-based reference signaling, the AoD value can be sent to the UE via PDCCH, MAC signaling, or other DL signaling, while the beam pattern and antenna configuration can be sent via RRC signaling or UE category information, etc.

[0069] These specific signaling examples are illustrative and not intended to be restrictive.

[0070] Figure 1 The examples in this disclosure are not limiting, and the contents of this disclosure can be extended to other numbers of RF chains, shapes, and / or orientations of antenna element subarrays.

[0071] Compared to conventional beamfinding with gradually decreasing beamwidth, some embodiments disclosed herein allow for the acquisition of accurate AoA and AoD values ​​using a relatively wide beam and based on the phase difference. This is illustrated by the phase-estimated MSE, which is given below for α. rz To illustrate with examples:

[0072]

[0073] Among them, E R This refers to the received power of each antenna element without beamforming. N0 is the variance of the additive white Gaussian noise (AWGN) in a channel where the mean and variance N0 are zero. R and G T It is beamforming gain.

[0074] It should be noted that due to the modulo operation involved in the phase values ​​defined above, these values, and any AoA or AoD determined based on the phase values, are subject to ambiguity. This can be mitigated by other measurements, or if the tilt angle is limited, for example by beamwidth. Within that range. If Then there is no ambiguity in the phase.

[0075] Similar analysis and similar annotations apply to those with ζ rl Instead of φ rl α rx The value of φ. A similar case applies to those with φ. tl α tz and having ζ tl α tx .

[0076] Some embodiments involve estimation using a single RF chain. In this case, there is one RF chain, which is quite common in UEs, for example. For each tilt direction, two beam patterns can be used to provide a basis for comparison. For example, the two beam patterns can cover the same direction but have different precoding vectors. Beamformers [Q1Q2] are considered in the first example and in the second example. Here, Q1 and Q2 are different sub-precoders with the same beam direction and the same length. An example is Q2 = Q1exp(jγ), where... D is the side length of the antenna array in the relevant direction, φ mid This refers to the tilt angle in the middle of the beam pattern. Two receptions at different times can be used to estimate the beam difference. In this example, each AoA tilt measurement involves two measurements. A similar method can also be used for AoD measurements. The phase difference or AoD estimate can be reported using signaling, as in other embodiments.

[0077] This technique allows phase difference-based estimation to be extended to a single RF chain. The single RF chain is used multiple times to collect the received signal for comparison.

[0078] Another embodiment involves estimating AoA and AoD based on the effects of beam skew.

[0079] When the BW is very large, signals arrive at different antenna elements at slightly different times, but the time difference is comparable to the signal chip rate. This time difference can be used to provide a better AoA estimate. Conversely, signals from different Tx antenna elements arrive at the same Rx antenna element at slightly different times; again, the time difference is comparable to the signal chip rate. This time difference can be used to provide a better AoD estimate. The time difference can be measured by any of a variety of different methods, such as directly by measuring the arrival times at different RF chains, or by using correlation values ​​as a result of PN sequence selection. An example of using correlation values ​​for this purpose is provided below.

[0080] Figure 2 This is a block diagram illustrating an exemplary antenna array comprising two uniform linear arrays (ULAs) 210 and 220, each connected to a corresponding RF chain. (See above) Figure 1 As stated, the RF chain is not in Figure 2 To avoid further crowding in the accompanying drawings, but for this example, consider a system with a disconnected subarray array comprising two ULA 210, 220 and two RF chains. Each of the ULA 210, 220 includes multiple antenna elements. Due to beam skew effects, the received signal (x) at different adjacent antennas is delayed by (τ). d This depends on AoA and the antenna spacing d, as shown in the figure.

[0081] One or both of AoA and AoD can be estimated by utilizing the effect of beam skew on the autocorrelation function of the maximum length (ML) pseudo-noise (PN) pilot sequence. For illustrative purposes, it is assumed that two ULA 210, 220s use the same beam pattern and perform that beam scan. Figure 2 As shown, AoAψ is relative to the line of sight of the array, and can be related, for example, to the tilt angle φ mentioned elsewhere in this document.

[0082] For beam deflection, the time delay τ d Depends on ψ, τ d =d sin(ψ) / c, where c is the speed of light. Therefore, on the channel or path l, compared to the case without beam deflection, the cross-correlation between the received signal (Y1) coupled to RF chain 1 of ULA 210 and the pilot sequence (X(t)) is...<Y1(t),X(t)> The cross-correlation ρ1 has decreased.

[0083]

[0084] Among them, h lE is the channel coefficient for path l. X X is the energy, M′ is the number of antennas in each ULA 210, 220, w is the beamformer vector, and N is the energy of X. c It is the length of the pilot sequence, T c This is the chip duration. For simplicity, noise is ignored. It should be noted that τ is the duration of the chip when there is no beam deflection or when the signal arrives from the line of sight (ψ = 0). d =0. The cross-correlation of the received signal (Y2) at RF chain 2 coupled to ULA220 can be represented in a similar manner, where the two RF chains have the same beamformer.

[0085] These cross-correlations are related to AoA, and can be used from the ratio |ρ2| when both Y1 and Y2 are affected by additive white Gaussian noise (AWGN) with zero mean and variance N0. 2 / |ρ1| 2 Estimate ψ, which can be, for example, the ratio of RSSI2 / RSSI1 or the signal-to-noise ratio (SNR). This enables AoA estimation and beamforming methods involving beam scanning, such as beam selection based on the highest SNR, and beamforming based on |ρ2|. 2 / |ρ1| 2 The AoA is estimated. Then, a narrow beam can be formed in the direction of the determined AoA. It should be noted that this AoA estimation differs from the amplitude comparison technique used in monopulse radar for MIMO systems. For applicable radar techniques, the difference in RSSI or SNR arises from the tilt of the beam direction, while according to the embodiments disclosed herein, this difference arises from beam deflection effects.

[0086] AoD can be determined in a substantially similar manner, but based on measurements on the device receiving reference signaling transmitted using ULA210, 220. Similar to other embodiments, signaling can be used in beam-skew-based embodiments to send the correlation value, or more generally another measure representing the time difference, to the transmitter, or the AoD value can be communicated to the transmitter if the AoD is estimated at the receiver.

[0087] This technique and beam scanning can be used to estimate AoA and AoD. The estimation error range of this technique can be narrower than the beamwidth itself. Furthermore, as the bandwidth increases while the beamwidth used for beam scanning remains constant, the estimation accuracy can be improved and the estimation error range can be reduced.

[0088] Several illustrative exemplary embodiments have been described above. As a further explanation, these embodiments can be considered within the context of a system model, where it is assumed that the antennas at each of the transmitter and receiver sides are in a two-dimensional (2D) array. One transmitter antenna element, wherein... It is the number of rows. It is a sequence number; similarly, there exists One receiver antenna element, among which... It is the number of rows. It represents the number of paths. The channel consists of L paths, each with a delay τ. l l = 1, ..., L, and the departure angle and arrival angle θ in the standard mathematical spherical coordinate system. tl φ tl θ rl φ rl , where θ tl and θ rl φ represents the departure and arrival azimuths associated with path l, respectively. tl and φ rl These represent the departure and arrival polar angles associated with path l, respectively. The channel coefficients associated with path l are determined by h. l It indicates that adjacent antenna elements are spaced a certain distance d apart.

[0089] For this channel model, as an illustrative and non-limiting example, the antenna element (m) at the transmitter can be shown. T ,n T ) and the antenna element at the receiver (m R ,n R Time-varying impulse response of the channel between ) Depend on It means that, among them:

[0090]

[0091] t T This is the timestamp of the transmitted signal leaving the receiver, where t is the flight time between the transmitter and receiver. For time-invariant channels, the timestamp can be removed.

[0092]

[0093] Without loss of generality, we assume that the time reference is related to the Loss of Sight (LoS) path (shown as zero delay), and all other paths are represented by the time difference of flight related to the LoS path. In the above model, we assume that diffraction is finite and negligible, and for now, we assume that beam skew is negligible. Under these conditions:

[0094]

[0095] in, and This represents the Kronecker product. This formula represents the channel between all transmit antennas and all receive antennas, where the channel between each transmit antenna and receive antenna is given in the previous formula.

[0096] For the sparse representation above, the channel consists of L paths, each path having a channel coefficient h. l Complex numbers, the delay τ of each path except the Loss path. l A real value is associated with AoA and four real values ​​with AoD. Therefore, the total number of real values ​​required to represent the channel is 7L–1.

[0097] For the AoSA structure, the received signal can be represented as follows:

[0098]

[0099] Where Q and P are timestamps t T The analog beamformer / pre-encoder used Let represent convolution, and z(t) represent noise. In the case of a non-overlapping AoSA structure, Q and P can be represented as block diagonal matrices such that P has no rows containing more than one non-zero element, and Q has no columns containing more than one non-zero element. In the above expression for the received signal, it is assumed that at timestamp t... T The channel remains constant throughout the transmission duration.

[0100] Focusing on timestamp 0, if the chosen signal x(t) has good autocorrelation, then for a sufficiently large Δt, The cross-correlation function of functions x(t) and y(t) over the transmission duration T is defined as follows: For a good PN sequence, with a transmission bandwidth of B and ΔtB>1, the autocorrelation function is very low and proportional to 1 / BT.

[0101] In this case, if the path delay is greater than 1 / B, the received signal is different from x(t–τ). l The cross-correlation of ) can be written as:

[0102]

[0103] Assumption<X(t),X(t)> =I, where I is the identity matrix, E X It is the energy transmitted by X, z XIt is the noise projected onto X(t), which is Gaussian noise with energy N0 (assuming unit energy of precoder P and Q).

[0104] Some embodiments use different beamformers P for K different timestamps. k Q k Let k = 1, ..., K. For ease of illustration, it is assumed that the channel remains constant over all K timestamps and that no value changes. The channel may not remain constant over all K timestamps, and one or more of the values ​​may change in practice in embodiments consistent with this application.

[0105] Regarding time or time separation, by looking at the cross-correlation of all K timestamps, it can be found that L time delay and sparse detection will be limited to a single path, or a finite number of paths, in cases where it is unlikely that more than one reflection path exists and the relative delay is comparable to 1 / B. In one example, it is not necessary to precisely estimate the time delay value. The time delay value can be estimated accurately enough to separate paths in time. In this case, each path can be estimated individually through simple time filtering.

[0106] For example, consider the special case of a receiver having two RF chains and two vertical ULAs, such as Figure 2 As shown in 210 and 220, each ULA has a row N. R The antenna element has an RF chain on the transmitter. In this example, the tilt angle is important. Further assuming that at time k, both RF chains use the same beamformer (Q0). k1 ).but Among them, Q k1 It is the length N R The row vector, where 0 is the length N. R The zero row vector. In this case, the effect of noise is ignored:

[0107]

[0108] The phase of the covariance of the received signal indicates the direction of arrival, but there is some ambiguity. However, knowing the vector Q... k1 The coverage of specific directions can resolve this ambiguity. It's worth noting that using this method, accurate AoA and AoD estimations can be achieved without very narrow receive and transmit beams. However, these beams should also not be too wide to help avoid ambiguity caused by phase entanglement. Exemplary beamwidths are provided elsewhere in this document.

[0109] All transmitting and receiving antennas can cooperate simultaneously. In all beam pairs P k and Qk In the middle, a few beams may have relatively high power. And it can focus on directions associated with these direction pairs or some of these directions.

[0110] Similarly, if there are two RF chains at the transmitter and one RF chain at the receiver, and both Tx RF chains use the same beam matrix... Among them, P k1 It is the length N T A column vector, where 0 is the length N. T The zero column vector, and the signal Where x1(t) and x2(t) have low autocorrelation and cross-correlation, then

[0111]

[0112] Similarly, the phase of the received signal can be used to calculate or otherwise determine the AoD at the transmitter.

[0113] The example of two Tx RF chains and one Rx RF chain above can be extended to multiple RF chains and 2D antenna setups on each side. This will be explored further below in the context of the potential ambiguity in signal-to-noise ratio (SNR) and AoA and AoD calculations. It should be noted that in the case of any interference source (e.g., from other signals or transmitters), SNR can refer to signal-to-interference-noise ratio (SINR).

[0114] Assuming two or more receiving beams are used in the AoSA structure, by α rz The phase difference of the received signal is calculated based on two beams, the centers of which are N apart in the z-direction. D d(where, as we know from the example above, N) D =N R / 2). The focus is on finding the derivative of φ in the tilted domain. rl The diagram shows AoA, φ rl It can be estimated as α rz A function that satisfies the following formula:

[0115]

[0116] Among them, c rφ It is an integer (i.e., (representing the set of integers {…,–2,–1,0,1,2,…}), 2c rφ π represents φ rl Phase entanglement ambiguity.

[0117] Three messages can be gleaned from this equation:

[0118] (1) The accuracy associated with AoA is much higher than that of the phase difference. AoA(φ rl The SNR of ) is actually with Proportional, while α rz The SNR is typically accurate within a small fraction of radians.

[0119] (2)φ rl Relative to α rz The derivative of the beam increases as the beam reaches the so-called "end-fire" (where, This increases the AoA and AoD estimates. Therefore, if the receiver is located near the end-fire beam direction (in this example, corresponding to the receiver being located above or below the antenna panel), this technique does not improve the AoA and AoD estimates compared to the width of the received and transmitted beams. However, for most directions of interest, this results in a frequency modulation (FM)-like SNR enhancement, thereby increasing φ. rl The mean square error (MSE) of the measurement ratio is related to α. rz The MSE measurement is better.

[0120] (3) In determining the integer value c rφ There may be ambiguities when choosing the actual beam direction for derivation. rφ The scope is limited to the beamforming matrix Q k If the original beam covers a region of space, then... but For example, by appropriately selecting the beamformer Q k By conducting multiple measurements, the ambiguity problem can be resolved.

[0121] It's worth noting that the definitions of polar angle and azimuth angle are different, therefore the derivations for these two angles are different. However, to find the beam direction relative to antenna elements in the same row, a better approach is to use the tilt angle relative to the x-axis (defined as ζ in this paper) to rewrite the same equation for the beam direction in the azimuth direction: cosζ = sinφcosθ. Therefore, if the measurement centers are spaced N in the x-direction... D The phase difference between the two beams of d and α rx The phase difference, then

[0122]

[0123] Among them, c rζ It is an integer, 2c rζ π represents ζ rl Phase entanglement ambiguity.

[0124] Similarly, considering Figure 1 However, in an AoSA system on the Tx side, if two signals from two Tx RF chains located in the z or x direction are received on the same Rx RF chain, with a phase difference of α... tz and α tx ,but

[0125]

[0126]

[0127] Among them, c tφ and c tζ It is an integer, 2c tφ π and 2c tζ π represents φ tl and ζ tl Phase entanglement ambiguity.

[0128] If a 2D antenna setup exists with 4 RF chains, each connected to a quarter of the antenna element, then both the azimuth and polar angles can be derived simultaneously.

[0129] During the hierarchical beamforming process, the receive beamforming matrix Q in different directions can be reduced without any feedback to the transmitter. In open-loop scenarios, the P matrix is ​​pre-assigned and cannot be optimized during the optimization process. However, if the system is closed-loop, the P matrix can also be reduced to the useful directions.

[0130] If signals from different directions and more than one path arrive within the same time range and cannot be distinguished by time, then different values ​​of AoA and AoD can be observed depending on the direction of Q.

[0131] Knowing the AoA and AoD from all directions, the complex number L associated with the channel coefficients can be determined using a K×L measurement of the channel. It should be noted that the K×L measurement is based on K timestamps, each timestamp being associated with τ. l The delay is related, l = 1, ..., L. Furthermore, since narrow beams can be formed in one or several directions, such as the beam with the highest RSSI or SNR, AoA and AoD estimations can be performed for some L paths rather than all L paths.

[0132] It should be noted that using two tilts in the example above does not distinguish between them. Figure 1Points on either side of the XZ plane, for example, assuming each antenna group lies on its own local coordinates and its XZ plane. The two XZ planes do not need to be parallel or have the same orientation. However, for 2D antenna systems, beamformers generate beams that are symmetrical with respect to the antenna plane, so no information is lost in this respect. This is a result of the beamformer, not due to the inherent pattern of the antenna elements. This phenomenon can be shown by the fact that the rear of the XZ plane is represented by an azimuth angle between π and 2π, but the exemplary beamforming formulas in this paper use cosθ, which does not distinguish between the front and rear of the XZ plane.

[0133] Some embodiments consistent with this application involve the use of a single RF chain. In the case of using a single RF chain at the receiver or transmitter, multiple RF chains can actually be simulated using partial antenna patterns.

[0134] For example, when some antenna elements can be turned off, the same transmission can be repeated with different antenna elements, such as once when the upper half of the antenna element is activated and once when the lower half of the antenna element is activated. This is equivalent to the transmission at timestamp t. T and t T +1 uses the following precoders: [Q1 0] and [0Q1] on the receiver, or [P1 0] and [0P1] on the transmitter.

[0135] If all antenna elements should be used and the phase can be adjusted, another possible option is, for example, to use an antenna pattern in the first transmission and repeat coefficients between different antenna elements (e.g., the top and bottom antenna elements mentioned above), and then change the phase of the bottom antenna element by a specific value, such as π, in the next time slot. The two RF chains can then be simulated using a simple Hadamard transform. This is equivalent to... T and t T +1 uses the following precoders: [Q1 Q1] and [Q1–Q1] at the receiver, or [P1 P1] and [P1–P1] at the transmitter.

[0136] In the example above, described within the context of an illustrative system model, the SNR of the l-th path is:

[0137] It is proportional to the spectral density of the transmitted power;

[0138] With ||h l The ||h is proportional to the square of ||h l || is inversely proportional to the path loss of the l-th path;

[0139] The beam gain is proportional to the beamwidth of matrices P and Q (when matrices P and Q are consistent with AoA and AoD of the l-th path), and inversely proportional to the beamwidth of P and Q.

[0140] It is proportional to the pilot length, which is in turn proportional to the bandwidth and duration of the signal;

[0141] It is inversely proportional to the noise power spectral density.

[0142] Regarding the pilot length, if the BW is large, the transmit power density will decrease for the same total transmit power. Furthermore, the energy E of the pilot... X It can be written as the transmit power spectral density multiplied by the pilot BW, and then multiplied by the pilot duration.

[0143] It should be noted that, due to the non-zero cross-correlation, the upper limit of SNR is defined by the pilot length. In other words, even in the absence of noise, SNR is limited by the cross-correlation value.

[0144] Now consider an example of detailed MSE calculation for the phase difference. Since the analysis is similar for all phase differences, α is considered. rz MSE calculation (i.e., For illustrative purposes, assume that the beamformer of Q1 is designed to cover a beam with a width of W. rd and W rp The solid angle of the beam (both defined in radians). Furthermore, it is assumed that the beam is flat in its location and zero everywhere else. In this case, the beam gain can be described as... Similarly, the beam gain associated with the pre-encoder P can be found. If the l-th path falls within both the transmitter and receiver beams, then the term... It can be described as E x ||h l || 2 G R G T If the measured phase difference is α rzm The noise-free phase difference is α rz The effect of noise can then be shown as follows:

[0145]

[0146] For the high of the l-th path The multiplication terms, which can be ignored due to noise, can be replaced with Gaussian noise with a variance of 2N0. This noise has two components, one perpendicular to vector E. x ||h l || 2 G R G T exp(jαrz One component is in phase, and each component has a variance N0. At higher SNR values, the in-phase term does not affect the results, and the MSE of the phase measurement can be shown as:

[0147]

[0148] Among them, E x =P T T x , where P T It is the transmission power, T X It is the duration of pilot frequency X.

[0149] in,

[0150]

[0151] but

[0152]

[0153] For other angles ζ rl φ tl and ζ tl The MSE can be used to derive similar expressions.

[0154] One observation regarding the MSE of the phase difference is that, when the beam scan covers multiple directions around the transmitter and receiver, the total scan overhead is proportional to the inverse of the transmitter and receiver gains, and the MSE of the measured phase difference can be rewritten as...

[0155]

[0156] Among them, T sweep It is the total time spent scanning the beam, Ω T and Ω R These are the solid angles scanned around the transmitter and receiver, respectively. If each of the transmitter and receiver scans all possible solid angles, these values ​​are all 4π. However, in most cases, the antenna panel scans a specific set of beam directions, such as in a three-sector deployment, reaching a maximum of 120 degrees in the azimuth direction.

[0157] Regarding beamformer design, it's crucial to determine the estimated channel beamforming accuracy. In the example above, the target angle accuracy was chosen. An overly precise estimate might not be helpful. For example, in... Figure 1 In the case of a 2D array, the beamwidth is inversely proportional to the number of antenna elements in the z or x direction. With this in mind, a specific target MSE can be defined with respect to the tilt angles relative to the x and z axes. The center of each beam determines the integer c. rφ c rζ ctφ and c tζ The target value. To avoid potential ambiguity, the beam width can be determined to limit the range of ambiguity and to accurately determine the phase associated with AoA.

[0158] For example, suppose the beam is positioned at a 60-degree angle to the antenna panel, which is equivalent to a 30-degree angle to the line of sight of the panel, and suppose the target accuracy of AoA is 1 degree, while the accuracy of the phase difference calculation is 30 degrees. phase difference accuracy and The MSE is associated with the accuracy, assuming the accuracy is within the average. Within the range. Among them,

[0159]

[0160] Assuming that a target accuracy of 1 degree is 30 times better than the phase difference calculation of 30 degrees in this example, where, The target accuracy then satisfies This means that if half the wavelength interval is used, then In other words, the phase difference of the beam separated by 11 antenna elements provides the target accuracy.

[0161] To limit the ambiguity of AoA values, the value c rφ The range should be set to equal to or less than 1. This means

[0162]

[0163] Or equivalently,

[0164]

[0165] get This can be shown as

[0166]

[0167] in, It is the beamwidth W. This is the center of the beam, assumed to be 60 degrees in this example. Using N... D =11, which will be abbreviated as

[0168]

[0169] In other words, the spacing between 11 antenna elements equals a beamwidth of 12 degrees. Therefore, starting with a beamwidth of 12 degrees or less and a pilot with sufficient SNR to estimate a phase difference within 30 degrees, an accuracy of 1 degree in the beam direction can be obtained. For THz deployments, in some examples, the initial beamwidth may be narrower than 12 degrees to achieve the desired SNR.

[0170] At this point, considering some simulation results may be helpful. In one example, for the purpose of simulation, assume that the antenna panels at each point in the network device and the UE include... Figure 1 The simulation employs four subarrays, each with 36 antenna elements arranged in a 6×6 square, spaced half a wavelength apart. The four subarrays themselves are arranged in a 2×2 square, with the subarray centers spaced three wavelengths apart. The center frequency used for the simulation is 150 GHz, with a bandwidth of 1 GHz. The network device antenna elements have an 8 dBi gain and a 130-degree 3 dB width pattern at both azimuth and elevation. In the simulation, these figures for the UE antenna are assumed to be 180 degrees and 5 dBi. Eighty-one beams are formed on each of the transmitter and receiver sides by forming nine beam options in each of the x and z directions for each of each transmitter and receiver. The resulting beam set on each of the transmitter and receiver consists of 81 beams, each covering a small area of ​​space spanning a 9×9 matrix in both the horizontal and vertical directions. Angles of arrival or departure within 80 degrees of the center are estimated for the beams. The objectives are as follows: (1) antenna beam pattern; (2) multiple sectors at the network device; (3) use of multiple antenna patches on different sides of the UE. Therefore, the width of each beam on each side is 160 / 9 = 17.8 degrees.

[0171] Figure 3 This is a graph illustrating the simulation results, showing the MSE in dB = 10 * log10(MSE), where MSE is the mean square error of the estimated angle in rads versus the received pilot energy-to-noise ratio in dB under these simulation conditions, and where, in this example, the c value (c... rφ c rζ c tφ and c tζ There is no ambiguity. Similar or different results can be observed under similar or different simulation or operating conditions for these and any other simulation results presented in this paper.

[0172] These results show that the gain (in dB) between MSE and pilot SNR is almost 55 dB. This can be explained as follows:

[0173] (1) There are 8 different paths for each angle estimate. For example, for the transmitter elevation angle, there are two side-by-side pairs on the transmitter and 4 receiver panels, which produces a 9dB gain.

[0174] (2) The beamwidth in each direction is 0.31 rad, resulting in a beam solid angle of 0.0963 sr. Beam gain This is based on the assumption that the beam is flat in the beam direction.

[0175] (3) By ignoring the denominator of the MSE gain, which is an angle that is almost perpendicular to the signal arriving at the receiver or being transmitted perpendicularly from the transmitter.

[0176] (4) The transmission power is distributed among the four panels, thus having a gain of –6dB.

[0177] (5) The SNR axis already includes antenna element gains of 5dB and 8dB respectively, resulting in a gain of –13dB. Again, this is based on an approximation using the assumption that the antenna element pattern is flat.

[0178] Based on the above, and using the approximation method or assumptions, the estimated SNR gain is 57.8 dB, which matches the simulation results well. At a moderate SNR of up to 10 dB, c rζ c rφ c tζ c tφ The values ​​may contain some ambiguity, which could lead to incorrect angle estimations. Figure 3 (Not shown in the image). This ambiguity can be reduced, for example, by further examining the beam through narrower beam scanning or beam retransmission. Other methods, such as reducing the possible beam angle range, can also be used, or alternatively, to reduce the likelihood of ambiguity.

[0179] For pilot energy-to-noise ratios less than -5dB, the estimation error does not follow the same principle. Figure 3 The same trend is shown. Figure 4 This is a graph showing the MSE and ratio of the estimated direction in dB. Figure 3 A lower received pilot energy-to-noise ratio.

[0180] As mentioned above, beam skew is a phenomenon associated with the large bandwidth available in the THz band. With such a large bandwidth, the transmitted symbols have very short periods, comparable to the difference in transmit / receive times on different antennas in a MIMO system, such as... Figure 2As shown. This behavior differs from that in microwave transmission, where it is assumed that transmission or reception by different antennas occurs simultaneously. Therefore, the received signals on different antenna elements are affected by ISI due to beam skew. By deploying multicarrier technology, the signals on different subcarriers appear to be transmitted from different directions.

[0181] Although beam skew causes ISI and degrades performance, it can also be used to estimate AoA, for example, by affecting the antenna array gain. Specifically, the delay between adjacent antenna elements depends on the antenna element spacing and AoA, so once the delay is determined, AoA can be estimated. The delay can be obtained from the performance degradation caused by beam skew or the level of ISI.

[0182] Will refer again Figure 2 The embodiments related to beam deflection are further described below, including disconnected subarrays of two ULA 210, 220, each connected to an RF chain (not shown). Beam deflection embodiments can also be extended to other array configurations. See reference... Figure 2 In the example described above, both antenna arrays use the same beam pattern and perform beam scanning. Although the example above refers to ψ as AoA, the other example below refers to far-field signals arriving at ULA210, 220 with a tilt angle of direction φ. As mentioned above, Therefore, the features disclosed by reference φ can also, or alternatively, be applied to ψ, and vice versa. It should be noted that the same estimation process applies to the AoA for each path l. Therefore, for simplicity, the path number subscript is not included in the symbol of AoA. Furthermore, a similar process applies to AoD, as shown in the following example.

[0183] In the case of beam deflection, the time delay (τ) between adjacent antennas depends on φ and is equal to τ. d =d·cos(φ) / c. To determine the delay, in some embodiments, the autocorrelation function of the ML PN sequence and the ratio of the SNR or received signal strength indicator (RSSI) on different RF chains are used.

[0184] Let pilot sequence X be of length N. c And the chip duration is T c The ML PN sequence. The autocorrelation function of this sequence is periodic, such as... Figure 5 As shown, within one cycle:

[0185]

[0186] By focusing on a chip cycle (T) c ),from Figure 5 As can be clearly seen from the expression above, the time delay can be obtained from the value of the autocorrelation function.

[0187] However, there are two main differences when considering the autocorrelation function in MIMO systems.

[0188] First, the received signal comprises multiple delayed versions of the pilot sequence. Therefore, the cross-correlation function is obtained by convolving the multiple delayed versions of the pilot sequence, which are affected by the channel coefficients. Compared to the case without beam skew, the cross-correlation function between the received signal at RF chain 1 (Y1) and the pilot sequence (X(t)) is...<Y1(t),X(t)> The cross-correlation ρ1 is reduced. The expression for ρ1 is given above.

[0189] Secondly, the maximum value of the autocorrelation function (in) Figure 5 The value shown as 1) may be unknown unless the receiver already knows the delay and is able to compensate for it. Therefore, a relative comparison between the cross-correlations on different RF chains can help estimate the delay and thus estimate AoA. Similar to ρ1, but with a shift M′, the cross-correlation between the pilot sequence and Y2 is shown below, where both RF chains have the same beamformer:

[0190]

[0191] Then, AoAφ in this example can be determined according to SNR2 / SNR1=|ρ2| 2 / |ρ1| 2 The ratio is estimated as described above for ψ. Considering the discrete Fourier transform (DFT) simulation of the beamformer, where, As an example, but it should be noted that other beamformers can be used.

[0192]

[0193]

[0194]

[0195]

[0196]

[0197] The above formula is based on After performing some mathematical operations and using the following identity, we obtain:

[0198]

[0199]

[0200] Figure 6 This is a graph showing the simulation results of SNR versus AoA (in this example, tilted AoA) for two RF chain examples, with and without beam skew effects. Figure 7 This is a graph showing the simulation results of the normalized SNR ratio versus the tilted AoA, where each of the two RF chains has 12 antennas. Figure 6 and Figure 7 The normalized SNR shown can be expressed as |ρ| 2 / (||h l || 2 E x / N0). It should be noted that if RSSI is plotted, |ρ| can be used. 2 / (||h l || 2 E x ).

[0201] As expected, greater gain can be obtained without beam deflection, but this cannot be achieved unless the AoA is known and delay elements are inserted on each antenna to align their received signals. To estimate the AoA, the gains at RF1 and RF2 can be used. Figure 2 In the example shown, RF1 has a greater gain than RF2 because the signal at the RF2 antenna has a longer delay. Figure 7 As shown, under each AoA, |ρ2| 2 / |ρ1| 2 The ratios are different. Figure 7 Clearly show that |ρ2| under φ=π / 2 2 / |ρ1| 2 =1. This is expected because all antennas simultaneously receive signals from the line of sight at that tilt angle. However, as φ decreases, different antennas begin to receive signals with longer delays and lower correlation (gain).

[0202] The above reference Figure 2 The provided example involves a linear array. However, it should be understood that similar analysis can be applied to 2D antenna arrays or any other antenna structure. Consider with Figure 1 and Figure 2 A similar 2D setup, but this 2D setup has multiple Tx and Rx antenna panels, each panel comprising four subarrays with 36 antennas. Figure 2In the dual ULA model, the timing delay actually begins from the top antenna of the top ULA 210. For the 2D array, in another example described below, the timing delay is considered to begin from the middle of the top left subarray at both the transmitter and receiver.

[0203] At the transmitter and receiver, 1, 2, 3, and 4 represent the top-left, top-right, bottom-left, and bottom-right subarrays, respectively, for example... Figure 1 The values ​​are 102, 104, 108, and 106. Furthermore, ρ... ij This represents the signal received by the i-th receiving subarray from the j-th transmitting subarray. Then, on the receiving side (AoA), by taking the ratio |ρ 21 | 2 / |ρ 11 | 2 When traversing the subarray horizontally, the tilt angle φ can be obtained. r Information about ζ can also be obtained when vertically traversing the antennas within the subarray. r Information about the value. Similarly, |ρ 31 | 2 / |ρ 11 | 2 Including information about φ r and ζ r The information. Therefore, each pair |ρ 21 | 2 / |ρ 11 | 2 and |ρ 31 | 2 / |ρ 11 | 2 Helps determine φ r and ζ r Similarly, for the transmitting side (AoD), for each pair |ρ 12 | 2 / |ρ 11 | 2 and |ρ 13 | 2 / |ρ 11 | 2 Helps determine φ t and ζ t .

[0204] For performance measurements of AoA estimation based on beam skew, the MSE can be expressed as:

[0205]

[0206] Among them, G T This refers to the transmit gain. It should be noted that the receiver gain (G) is... R Implicitly included in |ρ1|2 In addition, it should be noted that |ρ1| 2 / N0∝||h l || 2 E x / N0. The proof of this formula is as follows:

[0207] First, consider the noise term, where ρ′1=ρ1+z1(ρ′2=ρ2+z2), and MSE(φ) is defined as follows:

[0208]

[0209] Considering the definition above, we can obtain the last two terms on the right-hand side of the formula. Therefore, when the distance between antennas is d = 0.5λ, It should be noted that, and Therefore, f can be deleted. c And can be used replace Next, we can derive an approximate value for the first term on the right.

[0210] • To derive the first term on the right-hand side of the above formula, a similar MSE approximation using the phase difference method can be used.

[0211] In high SNR conditions, the last term can be ignored. Furthermore, since the third term is the conjugate of the second term, therefore...

[0212]

[0213] The approximation is obtained by ignoring the last term under high SNR. For ρ′2ρ′2 H A similar formula can be obtained.

[0214] Now, considering ρ′1ρ′1 H and ρ′2ρ′2 H The approximate value, and the expected term are as follows:

[0215]

[0216]

[0217] Among them, the approximate value (a) is derived from ρ′1ρ′1 in the previous step under high SNR. H and ρ′2ρ′2 H The approximate value is obtained; the approximate value (b) is also obtained from the high SNR assumption, where (c) is obtained because the average noise value is zero; (d) is obtained because... and And thus obtained.

[0218] Finally, by using the method given in the first step... The formula and the one given in the previous step Combining the formulas, we obtain MSE(φ) as shown above. It is clear from the MSE formula that end-fire of the ULA may be a potential problem. However, considering that multiple antenna locations can exist in communication devices such as UEs or network equipment, this is not expected to be a major issue.

[0219] It should be noted that |ρ1| 2 The larger the value, the smaller the MSE. For example, assuming the first antenna in ULA1 is the reference antenna in a linear array deployment, a higher correlation can be obtained when the reference antenna is considered as the intermediate antenna of ULA1, thus resulting in a larger |ρ1|. 2 However, the analysis and derivation will remain unchanged.

[0220] Figure 8 The figure shows the simulation results in the form of the estimated angle MSE and AoA, and also shows the relationship between the MSE performance of the proposed method and ψ (i.e., ), where each RF chain has 12 antennas and SNR = 10dB, G T =40. Figure 8 The AoA shown is the line-of-sight AoA, corresponding to (0.5π – tilt AoA), in radians (rad), or (90 – tilt AoA), in degrees.

[0221] refer to Figure 8 Within a maximum ψ = 70°, an average performance of -30dB or better is achieved. If the phase difference between the first and last antennas receiving the signal is less than one chip period, more antennas can be used to improve performance. If the delay exceeds the duration of the chip period, the cross-correlation with the pilot PN sequence will be very small (1 / N). c Moreover, it is useless. Any one or more of several methods can be used to solve such problems. For example, multiple panels can be used instead of multiple ULAs, where many antennas can be deployed in each panel for estimating azimuth and elevation. Another possible option is delaying and... Figure 2 The ULA220-related pilot sequence ensures that the correlation with the received signal at different antennas remains within the chip period duration. For example, by knowing... Figure 2The delay between the PN sequences in ULA210 and ULA220 can still be estimated from the ratio of SNR at RF1 and RF2 for AoA. The PN sequences can also be modified, or alternatively, to any one or more of the following: longer chip duration, different pulse shapes, and different correlation functions that provide more information over a longer duration.

[0222] about Figure 8 It should also be noted that when ψ approaches At the end-fire point of the ULA (i.e., 90 degrees) or where φ is close to 0, the MSE becomes high, which can be expected from the formula with a denominator of sin(φ) = 0. However, as mentioned above, since multiple antennas may be deployed at different locations of the communication equipment, the end-fire problem is not expected to be a major issue.

[0223] from Figure 8 It should also be noted that the MSE value varies by several dB within each beam. Consider the MSE at the beam center and edges. For example, a smoother curve of the MSE results can be obtained by using different simulated beamformers with almost constant gain across the beamwidth.

[0224] At least the above has described various embodiments for beam acquisition, in which AoA / AoD estimation helps determine the receive / transmit beam direction, while MSE calculation helps determine the beamwidth. Signaling supporting these embodiments may also be of interest. In some examples, network devices can generate beams with a direction determined based on AoA / AoD and a beamwidth determined according to MSE calculation.

[0225] For example, consider DL-based measurements. Configuration signaling used to configure reference signaling for the UE and network equipment (e.g., CSI-RS configuration signaling) can be substantially the same as the configuration signaling used for pilot allocation in the new radio (NR), but may have some reference signaling patterns or configurations, such as CSI-RS patterns / configurations. When the reference signaling pattern or configuration is signaled to the reference signaling receiver (for the UE in the case of DL-based measurements) or is available on the reference signaling receiver, the embodiments disclosed herein can be applied to determine one or more values ​​or metrics associated with AoD without requiring beam refinement or at least requiring fewer beam refinement iterations compared to conventional beam scanning and beam refinement techniques.

[0226] For DL-based measurements, AoA is estimated at the UE and is useful there; in some examples, AoA determination does not necessarily involve other signaling. For AoD estimation involving DL-based measurements, RRC and / or feedback signaling may have an impact. For example, one option involves receiver measurements. In some embodiments, configuration signaling is used to configure a receiver communication device, acting as a UE for DL-based measurements, to measure phase difference and / or beam skew power ratio, or functions or metrics associated with them, and report to a transmitter (in the case of DL-based measurements, a network device). This post-measurement reporting involves feedback mechanisms and signaling that are not part of conventional beam scanning and beam refinement techniques. In this example, configuration signaling is used to enable the UE to perform the measurement and report to the network device, which then estimates the AoD of the reference signaling it sends to the UE for the DL-based measurement, without requiring beam refinement or at least requiring fewer beam refinement iterations compared to conventional beam scanning and beam refinement techniques.

[0227] Another possible option for DL-based measurements involves receiver estimation. The antenna configuration and parameters used for beam scanning setup are signaled to or otherwise provided to the UE. The UE estimates the AoD based on the received reference signaling and feeds the AoD estimate back to the network device. In this example, the UE can estimate the AoD when the antenna configuration and parameters are signaled to the UE or are available at the UE, without requiring beam refinement or at least requiring fewer beam refinement iterations compared to traditional beam scanning and beam refinement techniques. The estimate reported to the network device also involves feedback mechanisms and signaling that are not part of traditional beam scanning and beam refinement techniques.

[0228] Moving to UL-based measurements, the configuration signaling used to configure UL reference signaling for the UE and network equipment (e.g., sounding reference signal (S-RS) configuration signaling) can be substantially the same as the configuration signaling used for pilot allocation in NR, but may have some reference signaling modes or configurations, such as S-RS modes / configurations. When the reference signaling mode or configuration is signaled to the reference signaling receiver (network equipment in the case of UL-based measurements) or is available on the reference signaling receiver, the embodiments disclosed herein can be applied to determine one or more values ​​or metrics associated with AoD without requiring beamfinding or at least requiring fewer beamfinding iterations compared to conventional beam scanning and beamfinding techniques.

[0229] Similar to DL-based measurements, in UL-based measurements, AoA is estimated on the receiver of the reference signaling and is useful on the receiver of the reference signaling, which is the network device used for UL measurements, and other signaling is not necessarily involved in AoA determination.

[0230] For AoD estimation involving UL-based measurements, there may be RRC and / or other DL signaling effects. For example, one option involves receiver measurements, in which configuration signaling is used to configure the receiver communication device, acting as a network device for UL-based measurements, to measure phase difference and / or beam skew power ratio, or functions or metrics associated with them, and report to the transmitter (UE in the case of UL-based measurements). This post-measurement reporting involves DL feedback mechanisms and signaling that are not part of conventional beam scanning and beamfining techniques. In this example, configuration signaling is used to instruct the network device to perform the measurement and report to the UE, and the UE then uses the information reported back by the network device to estimate the AoD of the reference signaling it sent to the network device for UL-based measurements, without requiring beamfining or at least requiring fewer beamfining iterations compared to conventional beam scanning and beamfining techniques.

[0231] Another possible option for UL-based measurements involves receiver estimation. The UE antenna configuration and parameters used for beam scanning setup are signaled to or otherwise provided to the network device, which estimates the AoD based on received reference signaling and feeds the AoD estimate back to the UE. Similarly, when the antenna configuration and parameters are signaled to the receiver (in this example, the network device) or are available at the receiver, the network device can estimate the AoD without beamfinding or at least with fewer beamfinding iterations compared to traditional beam scanning and beamfinding techniques. The estimate reported to the UE also involves feedback mechanisms and signaling that are not part of traditional beam scanning and beamfinding techniques.

[0232] The following is for reference. Figures 9A to 12 Illustrative examples of signaling consistent with the embodiments disclosed herein are provided. Other signaling methods are possible.

[0233] Figure 9A This is a signal flow diagram illustrating signaling according to an embodiment involving DL-based measurements. Figure 9AThe example illustrates a network device at 921, acting as a base station (BS), transmitting RRC signaling for configuring reference signaling (e.g., CSI-RS signaling) for UE 912. This CSI-RS signaling is subsequently transmitted from the BS to the UE at 920. RRC signaling is an example of configuration signaling, and CSI-RS signaling is an example of reference signaling that can be used in some embodiments during beam scanning. In the example shown, a beam scan is performed at UE 912 to find one or more receive beams and time-of-flight differences. More generally, during beam scanning, the receiver of the reference signaling (i.e., UE 912 receiving CSI-RS signaling 920) determines one or more receive beams that meet one or more beam acquisition criteria. Figure 9A The one or more optimal receive beams mentioned herein refer to examples of one or more receive beams that satisfy one or more beam acquisition criteria. Beam acquisition criteria can be based on any of a variety of features or characteristics, such as those described elsewhere in this document in the context of beam scanning and angle estimation. In some embodiments, for example, a beam acquisition criterion is satisfied if the reference signaling received via the beam satisfies an SNR or RSSI threshold.

[0234] At 924, the UE calculates the AoA for one or more paths, and one or more metrics associated with the AoD for one or more paths, as disclosed elsewhere in this document by way of example. The one or more metrics associated with the AoD may include any one or more of the following: phase difference, skew power ratio, correlation value, and other AoD-related values ​​disclosed herein. At 926, feedback signaling indicating one or more metrics associated with one or more AoDs is sent from the UE 912 to the BS 910. Then, at 928, the BS 910 estimates one or more AoDs based on the one or more metrics provided to the BS from the UE via feedback signaling 926.

[0235] Figure 9B This is a signal flow diagram illustrating signaling based on another embodiment involving DL-based measurement and AoD estimation. (See diagram for example.) Figure 9A As shown, in Figure 9B At point 961, BS 950 sends RRC signaling for configuring CSI-RS signaling for UE 952 (in the example shown). At point 963, BS 950 and UE 952 also exchange signaling. Figure 9B The parameters are shown in the diagram as CSI-RS parameters, enabling AoD estimation at the UE. Figure 9BThe signaling at 961 is shown as a bidirectional arrow to indicate the exchange of multiple messages between BS 950 and UE 952 to exchange CSI-RS parameters. In the example shown, a beam scan is performed at UE 952 to find one or more receive beams and time-of-flight differences, and the UE calculates not only the AoA for one or more paths, but also the AoD estimates for one or more paths, as disclosed elsewhere in this document by way of example. The estimated one or more AoDs are fed back to BS 950 in feedback signaling 966.

[0236] Figure 10A This is a signal flow diagram illustrating the signaling according to an embodiment involving UL-based measurements. Figure 10A The example shown is the same as Figure 9A The example shown is similar, except that at 1021, RRC signaling configures UE 1012 for S-RS signaling; at 1020, the reference signaling is S-RS signaling, and UE 1012 sends the reference signaling to BS 1010; at 1024, the BS calculates the AoA for one or more paths and calculates one or more metrics related to the AoD for one or more paths, feeding back one or more metrics to the UE in feedback signaling 1026; and at 1028, the UE calculates one or more AoDs based on the feedback from the BS. Regarding the reference signaling, in... Figure 10A In the diagram, UE 1012 is the transmitter, BS 1010 is the receiver, and... Figure 9A In this diagram, BS910 is the transmitter and UE 912 is the receiver.

[0237] Similarly, in illustrating another embodiment of signaling involving UL-based measurement and estimation... Figure 10B In the signal flow diagram, the reference signal transmitter and receiver roles of the UE and BS are relative to... Figure 9B The process is reversed. At 1061, BS1050 sends RRC signaling to UE 1052 for configuring reference signaling for the UE (in the example shown, in the form of S-RS signaling), and at 1063, exchanges one or more S-RS parameters with the BS. These one or more parameters enable BS 1050 to determine the AoD of one or more paths based on the S-RS signaling received from UE 1052 at 1060, and at 1066, the BS feeds back the estimated AoD of one or more paths to the UE in feedback signaling.

[0238] Examples of DL and UL have been provided above. However, it should be noted that the technologies disclosed in this paper can be applied to other scenarios, including device-to-device (D2D) communication, such as sidelink (SL) communication where the transmitter and receiver of the reference signaling are the UE. SL communication is described below as an example of D2D communication.

[0239] Figure 11A This is a signal flow diagram illustrating signaling based on an embodiment involving SL-based measurement and estimation. The SL-based embodiment can be substantially similar to the UL and DL embodiments, except for the beam scanning transmitter and receiver (in... Figure 11A In addition to UEs 1112 and 1114 shown in the examples, network devices may also be involved, such as... Figure 11A BS 1110 in the middle.

[0240] At 1121, BS 1110 configures UE 1112 for S-RS signaling by sending RRC signaling to UE 1112. In the example shown, signaling 1123 instructing UE 1112 for S-RS configuration is also forwarded by BS 1110 to UE 1114, enabling UE 1114 to perform beam scanning at 1122 to find one or more receiving directions and time-of-flight differences. In other embodiments, this signaling may be forwarded by UE 1112 to UE 1114. Based on the S-RS signaling received from UE 1112 at 1120, UE 1114 calculates the AoA of one or more paths at 1124, calculates one or more metrics associated with the AoD of one or more paths, and feeds back one or more metrics to BS 1110 in feedback signaling 1126 in the example shown. Then, BS1110 forwards one or more metrics from signaling 1127 to UE 1112, and at 1128, UE 1112 calculates one or more AoDs based on one or more metrics. In another embodiment, UE 1114 feeds back one or more metrics directly to UE 1112 via another frequency band (e.g., a low-frequency band).

[0241] Figure 11B This is a signal flow diagram illustrating the signaling according to an embodiment involving SL-based measurements. Figure 11B The examples in are basically the same as Figure 11A The example is the same, except that at 1148, BS 1130 calculates the AoD estimate for one or more paths based on feedback signaling 1146 from UE 1134 and sends one or more AoDs to UE 1132 in signaling 1147. At 1149, the exchange of one or more S-RS parameters between UE 1132 and BS 1130 enables the BS to perform AoD estimation. Although this exchange... Figure 11BThe diagram shows the S-RS configuration of UE 1132 occurring at 1145 before being forwarded to UE 1134 in signaling 1143. However, in other embodiments, the parameter exchange at 1149 and the forwarding of UE 1132's S-RS configuration to UE 1134 at 1145 can be performed in reverse order. Other variations, such as UE 1134 directly feeding back one or more metrics to UE 1132 and UE 1132 forwarding one or more metrics to BS 1130, are also possible. The S-RS signaling at 1140, the beam scanning at 1142, the calculation of one or more AoA and one or more metrics at 1144, and the feedback signaling at 1146 can be respectively... Figure 11A The numbers 1120, 1122, 1124, and 1126 are the same or substantially the same.

[0242] Figure 11C This is a signal flow diagram illustrating signaling based on another embodiment involving SL-based measurement and estimation. Figure 11A In the process, AoD estimation is performed at UE 1112, which sends reference signaling at 1120. Figure 11B In the middle, AoD is estimated at BS 1130, in Figure 11C In the example shown, AoD estimation is performed at UE 1154, which receives reference signaling from another UE 1152 at 1160. At 1161, BS 1150 configures UE 1152 for S-RS signaling via RRC signaling and exchanges one or more S-RS parameters with UE 1152 at 1169. In the example shown, in addition to the S-RS configuration of UE 1152, at 1165, one or more S-RS parameters of UE 1152 are also forwarded by BS 1150 to UE 1154 in signaling 1163. At 1162, UE 1154 performs beam scanning, and at 1165, one or more parameters signaled to UE 1154 enable UE 1154 to calculate AoA and AoD estimates for one or more paths at 1164. Then, UE1154 feeds back one or more estimated AoDs to BS1150 in feedback signaling 1166, and in the example shown, BS forwards one or more estimated AoDs to UE1152 in signaling 1167.

[0243] In other embodiments, the UE 1152 S-RS configuration and / or one or more beam scanning parameters may be forwarded to UE 1154 by UE 1152 instead of BS 1150. Another possible variation involves feeding back one or more estimated AoDs directly from UE 1154 to UE 1152. Other variations are also possible.

[0244] Figure 11D This is a signal flow diagram illustrating signaling according to yet another embodiment involving SL-based measurement and estimation. Figure 11D The example shown is basically the same as Figure 11C The examples are the same, but involve a different order of signaling, such as higher-layer signaling, for the S-RS configuration and parameters of UE 1172 to UE 1174 at 1185 in signaling 1183 and 1193. In other respects, the features shown in 1181, 1191, 1180, 1182, 1184, 1186, and 1187 can be compared with those shown in [the examples in 1183 and 1193]. Figure 11C The features of similar markers 1161, 1169, 1160, 1162, 1164, 1166, and 1167 are the same or substantially the same. (The above-mentioned...) Figure 11C Changes and other changes consistent with this application also apply. Figure 11D .

[0245] Turn now Figure 12 The signal flow graph in this figure illustrates signaling based on another embodiment involving channel reciprocity-based measurements and estimations using SL. Figure 12 In this configuration, BS 1211 configures S-RS signaling for each of the two UEs 1213 and 1215 via RRC signaling 1221 and 1241, and the BS notifies each UE of the other UE's S-RS configuration. As shown in the figure, at 1223, BS 1211 notifies UE 1213 of UE's S-RS configuration in signaling 1225, and at 1243, BS notifies UE 1215 of UE's S-RS configuration in signaling 1245. Each UE 1215 and 1213 performs beam scanning as shown in 1233 and 1253, respectively, and at 1235 and 1255, calculates the AoA of one or more paths based on the S-RS signaling 1231 and 1251 received from the other UE, respectively.

[0246] In scenarios where channel reciprocity exists, due to the relatively short distance between communication devices and the high probability of a single Loss of Path (LOS) path, which may be more common in D2D communication, one or more AoA on each UE 1213, 1215 can be used as one or more AoD from the same UE. Using one or more AoA as one or more AoD can be applied more generally to other embodiments where channel reciprocity exists, and is not necessarily limited to D2D communication.

[0247] Figure 13This is a flowchart illustrating an exemplary method according to an embodiment. In a basic form, exemplary method 1300 may involve a first communication device in a wireless communication network receiving reference signaling from a second communication device in the wireless communication network on two or more beams having the same direction, as shown in 1306, and determining one or more values ​​associated with the direction, as shown in 1308. Examples of reference signaling include... Figures 9A to 12 The CSI-RS signaling and S-RS signaling in the process.

[0248] In step 1308, one or more direction values ​​are determined based on the reference signaling received in step 1306, and these one or more direction values ​​are associated with the direction in which the first communication device receives the reference signaling from the second communication device. For example, this direction could be a direction that satisfies one or more beamforming criteria. Illustrative examples of beamforming criteria are provided elsewhere in this document.

[0249] The accuracy of the direction is higher than the accuracy of the beamwidth associated with the received reference signaling. While beam scanning and thinning according to conventional techniques can determine the direction within the accuracy of the antenna beamwidth used in beam scanning, the embodiments disclosed herein determine the direction with a higher accuracy than this beamwidth. For example, in a conventional synchronization signal block (SSB) beam scan, the network device transmits the SSB, and the UE transmits information about the SSB beam to the network in the reference signal received power (RSRP) feedback. Based on this feedback, the beam direction accuracy will be within the width of the SSB beam. However, according to the embodiments herein, a more precise beam direction is determined. For example, the direction determined according to the embodiments herein may have a narrower accuracy region or confidence range for the estimated AoA and / or AoD than the original beam used in the beam scan.

[0250] This direction can be the arrival direction of the reference signaling received by the first communication device from the second communication device, also referred to as AoA in this document.

[0251] In some embodiments, the direction associated with one or more values ​​in 1308 is the departure direction of the reference signaling transmission for which the first communication device receives reference signaling, also referred to herein as AoD. While AoA may be useful on the receiving communication device, AoD may be useful on the transmitting device receiving reference signaling in 1306. In some embodiments, the method involves sending signaling from the first communication device in 1310 indicating one or more values ​​associated with the departure direction. This signaling may be sent to a second communication device receiving reference signaling at 1304, or to another component, such as the BS in the SL embodiment discussed above. Examples of such signaling are... Figures 9A to 11D The signaling shown is the feedback signaling.

[0252] In some embodiments, the signaling sent at 1310 is sent to a second communication device to enable the second communication device to calculate the departure direction. In other embodiments, the signaling is sent to another component, such as the BS in the SL embodiment discussed above, to enable that other component to calculate the departure direction. One or more values ​​may be or include one or more metrics, such as those associated with the departure direction, and examples of these metrics are provided elsewhere herein.

[0253] The communication device receiving the reference signaling, referred to above as the first communication device, can itself calculate the departure direction. In this case, one or more values ​​associated with the departure direction can represent the departure direction. In some examples, one or more values ​​can be determined based on one or more of the following: path separation using beam scanning and time resolution, wherein the reference signaling is received through the path in two or more beams having the same direction; phase difference between measurements of the reference signaling received in two or more beams having the same direction; measurements of the reference signaling received by a single radio frequency (RF) chain at different times; beam skew.

[0254] The first communication device may receive additional signaling to enable it to calculate the departure direction. This additional signaling may be received from the second communication device or from another component (such as the BS in the SL example above).

[0255] This additional signaling is illustrated by way of example in 1304 and may be or include signaling indicating one or more parameters to be used by the second communication device when transmitting reference signaling. The additional signaling may also, or alternatively, include signaling indicating one or more of the following: beam pattern, beamwidth, antenna configuration, or antenna structure.

[0256] Typically, this additional signaling can be received by a component to enable it to calculate the departure direction. Examples of such signaling include indications of CSI-RS parameters (such as...). Figure 9B The signaling (as shown in 963) and the indication of S-RS parameters (such as...) Figure 10B 1020 places in the middle Figure 11B 1149 in the middle, Figure 11C At positions 1169 and 1163 in the middle and Figure 11D The signaling is shown at positions 1191 and 1193 in the diagram.

[0257] In some embodiments, as shown at 1302, the first communication device may receive signaling for configuring reference signaling for the first communication device. This may include, for example, RRC signaling received from a network device (e.g., a BS), and / or signaling for informing the first communication device of the reference signaling configuration of the second communication device, as described in the SL example above. Examples of RRC signaling and configuration forwarding are as follows: Figures 9A to 12 As shown.

[0258] and Figure 13 The consistent and / or consistent approach with other guidance herein can be implemented in any of a variety of scenarios. For example, the first communication device can be a UE, and the second communication device can be a network device in a wireless communication network, as described in the DL examples provided elsewhere in this document. The first communication device can be a network device in a wireless communication network, and the second communication device can be a UE, as described in the UL examples provided elsewhere in this document. The first communication device can be a first UE, and the second communication device can be a second UE, as described in the SL examples provided elsewhere in this document.

[0259] Other features may also be implemented, or alternatively, in the method embodiments. For example, the determination at 1308 may involve determining one or more values ​​based on at least one or more of the following disclosed in detail above: path separation using beam scanning and time resolution, through which reference signaling is received; phase difference between paths through which reference signaling is received on two or more beams having the same direction; phase difference between measurements of reference signaling received in two or more beams having the same direction; measurements of reference signaling received by a single RF chain at different times; beam skew.

[0260] The above reference Figure 13 The described method features and / or other features disclosed herein may also be implemented, or alternatively, in the form of a processor-readable memory storing processor-executable instructions, which, when executed by one or more processors on a first communication device in a wireless communication network, cause the one or more processors to perform the method. For example, a method may include: the first communication device receiving reference signaling from a second communication device in the wireless communication network in two or more beams having the same direction; and, based on the received reference signaling, determining one or more values ​​associated with the direction in which the first communication device receives the reference signaling from the second communication device. The accuracy of the direction is higher than the accuracy of the beamwidth associated with the received reference signaling.

[0261] Other features disclosed herein may be implemented in such processor-readable storage embodiments. For example, in some embodiments, the above references may be provided in any of a variety of combinations. Figure 13And / or any one or more of the other features disclosed herein.

[0262] Figure 14 This is a flowchart illustrating an exemplary method according to an embodiment. Figure 13 The exemplary method 1300 illustrates operations that can be performed on the receiving device or receiving side during beam acquisition in some embodiments. Figure 14 The exemplary method 1400 illustrates operations that can be performed on the transmitting device or transmitting side or elsewhere during beam acquisition in some embodiments.

[0263] A basic form of this method may involve transmitting reference signaling from a second communication device in a wireless communication network to a first communication device at point 1406 in two or more beams having the same direction, and the second communication device receiving signaling indicating one or more direction values, as shown at point 1408. One or more direction values ​​are determined by the first communication device and associated with the transmission direction (also referred to herein as AoD) of the reference signaling from the second communication device, from which the first communication device receives the reference signaling. The accuracy of the direction associated with the one or more values ​​is higher than the accuracy of the beamwidth associated with the reference signaling. As described elsewhere herein, this direction may be the direction from which the first communication device best receives the reference signaling, or a direction that otherwise satisfies one or more beam acquisition criteria.

[0264] The signaling at 1408 can be received from the first communication device or from another component (such as the BS in the SL example above).

[0265] Some embodiments may involve sending signaling to a first communication device for configuring reference signaling for the first communication device. This is shown at 1402. Such signaling may include, for example, RRC signaling for configuring the first communication device, and / or other signaling for informing the first communication device of the reference signaling configuration of a second communication device. The signaling in 1402 may be sent from the second communication device and / or from another component (e.g., the BS in the SL example above) to the first communication device.

[0266] One or more direction values ​​at 1408 enable a second communication device or another component (such as the BS in the SL embodiment described above) to calculate the transmission direction of the reference signaling at 1410. In other embodiments, the communication device receiving the reference signaling (referred to above as the first communication device) can calculate the transmission direction, in which case one or more direction values ​​referenced at 1408 can specify the direction. At 1404, additional signaling can be sent to the first communication device to enable it to calculate the direction. This additional signaling can be sent by the second communication device or another component (such as the BS in the SL example described above).

[0267] Such additional signaling may be or include signaling instructing the second communication device to use one or more parameters when transmitting reference signaling at 1406. Signaling used to enable the first communication device to calculate the departure direction may also, or alternatively, include signaling instructing any one or more parameters such as beam pattern, beamwidth, antenna configuration, or antenna structure. Other examples of such additional signaling are provided elsewhere in this document.

[0268] and Figure 14 A consistent and / or consistent approach with other guidelines in this document can be implemented in any of a variety of scenarios, including at least those referenced above. Figure 13 The following examples are provided, wherein: the first communication device is a UE and the second communication device is a network device; the first communication device is a network device and the second communication device is a UE; or, the first communication device is a first UE and the second communication device is a second UE.

[0269] In embodiments involving determining a value associated with direction, the determination at 1408 may involve determining a value based on at least one or more of the following disclosed in detail above: path separation using beam scanning and time resolution, with reference signaling received through the path in two or more beams having the same direction; phase difference between measurements of reference signaling received in two or more beams having the same direction; measurements of reference signaling received by a single RF chain at different times; beam skew.

[0270] These and other features may also be implemented, or alternatively, in the form of a processor-readable memory storing processor-executable instructions that, when executed by one or more processors on a second communication device in a wireless communication network, cause the one or more processors to perform a method. For example, a method may include: transmitting reference signaling from a second communication device to a first communication device in two or more beams having the same direction; the second communication device receiving signaling indicating one or more values ​​determined by the first communication device and associated with the transmission direction of the reference signaling, the first communication device receiving the reference signaling from the transmission direction. As noted herein with respect to other embodiments, the accuracy of this direction is higher than the accuracy of the beamwidth associated with the reference signaling.

[0271] Other features disclosed herein may be implemented in such processor-readable storage embodiments. For example, in some embodiments, the above references may be provided in any of a variety of combinations. Figure 14 And / or any one or more of the other features disclosed herein.

[0272] Various embodiments have been disclosed through the examples above. Figure 15An exemplary communication system 1200 that can implement embodiments of this application is shown. Typically, the communication system 1200 enables multiple wireless or wired components to transmit data and other content. The purpose of the communication system 1200 may be to provide content (voice, data, video, text) to user equipment, etc., via broadcast, unicast, multimedia broadcast multicast service (MBMS), or user equipment. The communication system 1200 can operate by sharing resources (e.g., bandwidth).

[0273] In this example, the communication system 1200 includes electronic devices (EDs) 1210a-1210c, radio access networks (RANs) 1220a-1220b, a core network 1230, a public switched telephone network (PSTN) 1240, the Internet 1250, and other networks 1260. Although Figure 15 A certain number of these components or elements are shown, but the communication system 1200 may include any reasonable number of these components or elements.

[0274] EDs 1210a to 1210c are used for operation and / or communication in communication system 1200. For example, EDs 1210a to 1210c are used for transmission and / or reception via wireless or wired communication channels. Each ED 1210a to 1210c represents any suitable end-user equipment for wireless operation and may include (or be referred to as) devices such as: user equipment (UE / user device), wireless transmit / receive unit (WTRU), mobile station, fixed or mobile subscriber unit, cellular telephone, station (STA), machine type communication (MTC) device, personal digital assistant (PDA), smartphone, laptop computer, computer, tablet computer, wireless sensor, or consumer electronic device.

[0275] exist Figure 15In this configuration, RAN 1220a to 1220b include base stations 1270a and 1270b, respectively. Each base station 1270a and 1270b is used to establish a wireless connection with one or more EDs (Edges) among EDs 1210a to 1210c, enabling access to any other base stations 1270a and 1270b, core network 1230, PSTN 1240, Internet 1250, and / or other networks 1260. For example, base stations 1270a and 1270b may include (or may be) one or more of several well-known devices, such as a base transceiver station (BTS), Node-B (NodeB), evolved NodeB (eNodeB), Home eNodeB, gNodeB, transmission point (TP), site controller, access point (AP), wireless router, or network access node of 6G or higher. Any ED 1210a to 1210c may optionally or additionally be used to connect, access, or communicate with any other base stations 1270a and 1270b, the Internet 1250, the core network 1230, the PSTN 1240, other networks 1260, or any combination thereof. Communication system 1200 may include a RAN, wherein the corresponding base station accesses the core network 1230 via the Internet 1250. In some embodiments, EDs 1210a to 1210c include EDs capable of communicating directly with each other via a direct radio link 1280, which is also often referred to as a sidelink. In some embodiments, base stations 1270a and 1270b may be at least one of terrestrial base stations or non-terrestrial base stations (e.g., flying base stations).

[0276] EDs 1210a to 1210c, as well as base stations 1270a and 1270b, are examples of communication devices that can be used to implement some or all of the functions and / or embodiments described herein. Figure 15In the illustrated embodiment, base station 1270a constitutes part of RAN 1220a, which may include other base stations, one or more base station controllers (BSCs), one or more radio network controllers (RNCs), relay nodes, components, and / or devices. Any base station 1270a, 1270b may be a single component, as shown, or multiple components distributed throughout the corresponding RAN, etc. Furthermore, base station 1270b constitutes part of RAN 1220b, which may include other base stations, components, and / or devices. Each base station 1270a and 1270b transmits and / or receives radio signals within a specific geographical area (sometimes referred to as a "cell" or "coverage area"). Cells may be further divided into cell sectors, and base stations 1270a and 1270b may, for example, employ multiple transceivers to provide services to multiple sectors. In some embodiments, there may be established picocells or femtocells, supported by radio access technologies. In some embodiments, multiple transceivers may be used for each cell, for example, using MIMO technology. The number of RANs 1220a and 1220b shown is merely exemplary. Any number of RANs can be considered when designing the communication system 1200.

[0277] Alternatively, one or more base stations can form a cell, where multiple base stations within a cell can share the same cell identifier (ID). A cell including multiple base stations can be called a supercell. A supercell can include only at least one terrestrial base station, or only at least one non-terrestrial base station. A supercell can also include at least one terrestrial base station and at least one non-terrestrial base station. A cell or supercell can include base stations of the same type or different types. For example, a cell or supercell covering an area generated by one or more beampoints from one or more satellite base stations can also include one or more other types of terrestrial or non-terrestrial base stations. From the UE's perspective, a supercell can be an area covered by a virtual access entity. A supercell can include multiple base stations with the same cell ID. A supercell can be adjusted based on network topology, load distribution, or UE distribution. The supercell topology can be dynamically updated to adapt to changes in network topology, load distribution, and / or UE distribution.

[0278] Base stations 1270a to 1270b communicate with one or more EDs 1210a to 1210c via one or more air interfaces 1290 using radio frequency (RF), microwave, infrared (IR), or other wireless communication links. Air interface 1290 can utilize any suitable wireless access technology. For example, communication system 1200 can implement one or more channel access methods in air interface 1290, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or single-carrier FDMA (SC-FDMA).

[0279] Base stations 1270a and 1270b can implement Universal Mobile Telecommunication System (UMTS) Universal Terrestrial Radio Access (UTRA) to establish an air interface 1290 using wideband CDMA (WCDMA). In this case, base stations 1270a and 1270b can implement protocols such as HSPA and HSPA+, where HSPA+ optionally includes HSDPA and / or HSUPA. Optionally, base stations 1270a and 1270b can use LTE, LTE-A, and / or LTE-B to establish an air interface 1290 with evolved UTMS terrestrial radio access (E-UTRA). Considering that communication system 1200 can use multi-channel access capabilities, including those schemes described above. Other wireless technologies used to implement the air interface include IEEE 802.11, 802.15, 802.16, CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, IS-2000, IS-95, IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemes and wireless protocols can also be used.

[0280] RANs 1220a and 1220b communicate with the core network 1230 to provide various services, such as voice, data, and other services, to EDs 1210a through 1210c. RANs 1220a and 1220b and / or the core network 1230 may communicate directly or indirectly with one or more other RANs (not shown), which may or may not be directly served by the core network 1230 and may or may not use the same radio access technology as RANs 1220a and / or RAN 1220b. The core network 1230 may also act as a gateway access between (i) RANs 1220a and 1220b and / or EDs 1210a through 1210c, and (ii) other networks (e.g., PSTN 1240, Internet 1250, and other networks 1260). Additionally, some or all of ED 1210a to 1210c may include the ability to communicate with different wireless networks via different wireless links using different wireless technologies and / or protocols. Instead of wireless communication (or other than wireless communication), the ED may also communicate with a service provider or exchange (not shown) via a wired communication channel and with the Internet 1250. PSTN 1240 may include a circuit-switched telephone network for providing plain old telephone service (POTS). Internet 1250 may include a computer network and / or subnet (internal network) and includes protocols such as IP, TCP, and UDP. ED 1210a to 1210c may be multimode devices capable of operating according to multiple wireless access technologies and include multiple transceivers required to support these wireless access technologies.

[0281] Figure 16A and Figure 16B Exemplary devices are shown that can implement the methods and guidance provided in this application. Specifically, Figure 16A An exemplary ED 1210 is shown. Figure 16B An exemplary base station 1270 is shown. These components can be used in communication system 1200 or any other suitable system.

[0282] like Figure 16AAs shown, ED 1210 includes at least one processing unit 1300. The processing unit 1300 implements various processing operations of ED 1210. For example, the processing unit 1300 may perform signal encoding, data processing, power control, input / output processing, digital beamforming, or any other function that enables ED 1210 to operate within communication system 1200. The processing unit 1300 may also be used to implement some or all of the functions and / or embodiments detailed elsewhere herein. Each processing unit 1300 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 1300 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0283] ED 1210 also includes at least one transceiver 1302. Transceiver 1302 is used to modulate data or other content for transmission via at least one antenna or network interface controller (NIC) 1304. Transceiver 1302 is also used to demodulate data or other content received by at least one antenna 1304. Each transceiver 1302 includes any suitable structure for generating signals for wireless or wired transmission and / or for processing signals received wirelessly or wiredly. The structure for generating signals for wireless transmission and / or for processing signals received wirelessly is referred to herein as an RF chain. One or more RF chains may be provided. One or more analog beamformers may also be implemented in transceiver 1302. Each antenna 1304 includes any suitable structure for transmitting and / or receiving wireless or wired signals. 1D antenna structures (e.g., ULA) and 2D antenna structures (e.g., panels) as disclosed herein by example may be provided. More generally, one or more transceivers 1302 may be used in ED 1210. One or more antennas 1304 may be used in ED 1210. Although shown as a single functional unit, transceiver 1302 may also be implemented using at least one transmitter and at least one separate receiver.

[0284] ED 1210 also includes one or more input / output devices 1306 or interfaces (e.g., connected to...). Figure 15 (Wired interface of Internet 1250 in the network). Input / output device 1306 can interact with users or other devices in the network. Each input / output device 1306 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touchscreen, including network interface communication.

[0285] Furthermore, UE 1210 includes at least one memory 1308. Memory 1308 stores instructions and data used, generated, or collected by ED 1210. For example, memory 1308 may store software instructions or modules for implementing some or all of the functions and / or embodiments described herein, and executed by one or more processing units 1300. Each memory 1308 includes any suitable one or more volatile and / or non-volatile storage and retrieval devices. Any suitable type of memory can be used, such as random access memory (RAM), read-only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, etc.

[0286] like Figure 16B As shown, base station 1270 includes at least one processing unit 1350, at least one transmitter 1352, at least one receiver 1354, one or more antennas 1356, at least one memory 1358, and one or more input / output devices or interfaces 1366. Transmitters 1352 and receivers 1354 may be used instead of transceivers (not shown). Scheduler 1353 may be coupled to processing unit 1350. Scheduler 1353 may be included within base station 1270 or operate separately from base station 1270. Processing unit 1350 implements various processing operations of base station 1270, such as signal encoding, data processing, power control, input / output processing, digital beamforming, or any other functions. Processing unit 1350 may also be used to implement some or all of the functions and / or embodiments detailed herein. Each processing unit 1350 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 1350 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0287] Each transmitter 1352 includes any suitable structure for generating signals for wireless or wired transmission with one or more EDs or other devices. Each receiver 1354 includes any suitable structure for processing signals received wirelessly or wiredly from one or more EDs or other devices. As described above, the structures for generating signals for wireless transmission and / or for processing signals for wireless reception are referred to herein as RF chains. One or more analog beamformers may also be implemented in transmitter 1352 and / or receiver 1354. Although shown as separate components, at least one transmitter 1352 and at least one receiver 1354 may be combined into a transceiver. Each antenna 1356 includes any suitable structure for transmitting and / or receiving wireless or wired signals. 1D antenna structures (e.g., ULA) and 2D antenna structures (e.g., panels) as disclosed herein by example may be provided. Although a common antenna 1356 is shown coupled to both transmitter 1352 and receiver 1354, one or more antennas 1356 may be coupled to one or more transmitters 1352, and one or more individual antennas 1356 may be coupled to one or more receivers 1354. Each memory 1358 includes any suitable one or more volatile and / or non-volatile storage and retrieval devices, such as those described above. Figure 16A The devices described in ED 1210. Memory 1358 stores instructions and data used, generated, or collected by base station 1270. For example, memory 1358 may store software instructions or modules for implementing some or all of the functions and / or embodiments described herein, and executed by one or more processing units 1350.

[0288] Each input / output device 1366 can interact with users or other devices in the network. Each input / output device 1366 includes any suitable structure for providing or receiving information from users, including network interface communication.

[0289] It should be understood that one or more steps of the methods of the embodiments provided herein may be performed by the corresponding units or modules. Figure 17The embodiments shown are generally those including an operating system module, but other embodiments are also possible. For example, signals may be transmitted by a transmitting unit or transmitting module. Signals may be received by a receiving unit or receiving module. Signals may be processed by a processing unit or processing module. Other steps may be performed by an ML module. The corresponding units / modules may be implemented using hardware, one or more components or devices executing software, or a combination thereof. For example, one or more units / modules may be integrated circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). It should be understood that if the above modules are implemented using software for execution by a processor, etc., these modules may be retrieved by the processor, in whole or in part, individually or collectively, for processing, or in one or more instances as needed, and these modules themselves may include instructions for further deployment and instantiation.

[0290] Generally, apparatus embodiments for implementing the methods disclosed herein can take any of a variety of forms. For example, in one embodiment, a communication device for a communication network, such as a UE or network device, may include a receiver, a transmitter, a processor coupled to the receiver and the transmitter, and a processor-readable memory coupled to the processor. The processor-readable memory stores processor-executable instructions that, when executed by the processor, cause the processor to perform the method. Illustrative embodiments of the method are disclosed herein, and the instructions stored in the processor-readable memory, when executed, can cause the processor to perform any such method.

[0291] In one particular exemplary embodiment, a first communication device for a wireless communication network includes a receiver, for example, as shown at 1302, 1354, for receiving reference signaling from a second communication device in the wireless communication network on two or more beams having the same direction, and a processor coupled to the receiver, for example, as shown at 1300, 1350. The processor is configured to determine one or more values ​​associated with a direction based on the received reference signaling on the two or more beams having the same direction, by executing software stored in a memory, for example at 1308, 1358. This direction is the direction in which the first communication device receives the reference signaling from the second communication device, and the accuracy of this direction is higher than the accuracy of the beamwidth associated with the received reference signaling.

[0292] Features and examples described elsewhere in this document, such as those described in the reference methods, are also applicable to such embodiments. For example, an embodiment may include any one or more of the following features in any combination of various combinations:

[0293] The direction is the direction of arrival, and the first communication device receives reference signaling from the second communication device in the direction of arrival;

[0294] The direction is the departure direction of the reference signaling transmission, and the first communication device receives the reference signaling from the departure direction;

[0295] The first communication device also includes a transmitter coupled to the processor, for example at 1302, 1352, that transmits signaling indicating one or more values ​​associated with the direction of departure;

[0296] The receiver is also used to receive signaling for configuring reference signaling for the first communication device;

[0297] The transmitter is used to send signaling to a second communication device or another component indicating one or more values ​​associated with the departure direction, so that the second communication device or another component can calculate the departure direction;

[0298] The value associated with the departure direction can represent the departure direction;

[0299] The receiver is also used to receive other signaling, and the processor is used to determine the departure direction based on the reference signaling from the second communication device and the other received signaling;

[0300] Other signaling is or includes signaling that instructs the second communication device to use parameters when sending reference signaling;

[0301] Other signaling is or includes any one or more of the following: beam pattern, beamwidth, antenna configuration, or antenna structure;

[0302] The first communication device is the UE, and the second communication device is the network device in the wireless communication network.

[0303] The first communication device is a network device in a wireless communication network, and the second communication device is a UE;

[0304] The first communication device is the first UE, and the second communication device is the second UE;

[0305] The processor is configured to determine the value based on one or more of the following: path separation using beam scanning and time resolution, wherein reference signaling is received through the path on two or more beams having the same direction; phase difference between measurements of reference signaling received in two or more beams having the same direction; measurements of reference signaling received by a single radio frequency (RF) chain at different times; beam skew.

[0306] According to other embodiments, in one method, a second communication device transmits reference signaling to a first communication device in a wireless communication network on two or more beams having the same direction, and receives signaling indicating a value determined by the first communication device and associated with the transmission direction of the reference signaling, from which the first communication device receives the reference signaling, the direction having a higher precision than the beamwidth associated with the reference signaling. A communication device for a wireless communication network includes: a transmitter, for example, as shown at 1302, 1352, transmitting reference signaling to a first communication device in the wireless communication network on two or more beams having the same direction; and a receiver, for example, at 1302, 1354, receiving signaling indicating one or more values ​​determined by the first communication device and associated with the transmission direction of the reference signaling, from which the first communication device receives the reference signaling. The precision of the direction is higher than the precision of the beamwidth associated with the reference signaling.

[0307] Features and examples described elsewhere in this document, such as those described in the reference methods, are also applicable to such embodiments. For example, an embodiment may include any one or more of the following features in any combination of various combinations:

[0308] The transmitter is also used to send signaling to the first communication device for configuring reference signaling for the first communication device;

[0309] One or more values ​​associated with the transmission direction enable the communication device to calculate the transmission direction;

[0310] One or more values ​​associated with the transmission direction can represent the transmission direction;

[0311] The transmitter is also used to send other signaling to the first communication device so that the first communication device can calculate the transmission direction;

[0312] Other signaling is or includes signaling that instructs the communication device to use one or more parameters when transmitting reference signaling;

[0313] Other signaling is or includes one or more of the following: beam pattern, beamwidth, antenna configuration, or antenna structure;

[0314] Communication equipment is network equipment in a wireless communication network; the first communication device is the UE (User Equipment).

[0315] The communication device is the UE, and the first communication device is the network device in the wireless communication network;

[0316] The communication device is the first UE, and the first communication device is the second UE;

[0317] The value is determined based on one or more of the following: path separation using beam scanning and time resolution, with reference signaling received by the first communication device through the path in two or more beams having the same direction; the phase difference between measurements of reference signaling received in two or more beams having the same direction; measurements of reference signaling received at different times by a single RF chain on the first communication device; and beam skew determined by the first communication device.

[0318] Typically, this application envisions embodiments that utilize techniques such as time-separation of the channel and beam scanning to obtain an ultrasparse representation of a channel with a sparse order having at most one non-zero element. Some embodiments use the phase difference and / or time difference of signals received by multiple antenna arrays to estimate the channel. Signaling for, for example, reporting metrics or values ​​associated with AoD is also considered. Single-RF-chain and multi-RF-chain applications are possible.

[0319] The disclosed embodiments also include using phase and correlation differences indicating time differences to estimate channels in the THz region, where the channels are represented by a sparse model separated in time and direction. Some of these techniques can be used in certain mmWave deployments, such as when the channel comprises several paths in different directions. Furthermore, the correlation value is not necessarily an indicator of the time difference. Other mechanisms, such as directly estimating the timing within each antenna subarray, can also be used for the same purpose.

[0320] Although some embodiments of beam acquisition disclosed herein may begin with beam scanning and beam refinement, the techniques disclosed herein can reduce the number of beam refinement cycles compared to existing processes such as synchronization signal block (SSB) and random access channel (RACH) procedures.

[0321] Currently, beamfining processes are often closed-loop. A finer CSI-RS beam is built based on a wider CSI-RS or SSB beam reference signal received power (RSRP) feedback (which introduces more feedback overhead and delay). The embodiments disclosed herein include those that can be open-loop or have fewer closed-loop steps. Beam skew and phase difference measurements are based on a wider beam RSRP measurement, and the feedback metric (e.g., phase difference or power ratio) can be a scalar value for each identified or reported path, in many cases including a Loss of Sight (LoS) path or the strongest beam.

[0322] Based on the above guidance, many modifications and variations can be made to this application. Therefore, it should be understood that this application may be practiced in ways other than those specifically described herein, within the scope of the appended claims.

[0323] The description is merely an illustration of the application of the principles of the embodiments of this application. Other arrangements and methods can be implemented by those skilled in the art.

[0324] For example, although combinations of features are shown in the illustrated embodiments, not all features need to be combined to achieve the benefits of the various embodiments of this application. In other words, a system or method designed according to embodiments of this application does not necessarily include all features shown in any of the figures or all portions schematically illustrated in the figures. Furthermore, selected features of one exemplary embodiment may be combined with selected features of other exemplary embodiments.

[0325] For example, the beam deflection-based implementation can be combined with the implementation involving phase difference-based estimation to reduce the AoA / AoD estimation at the outset, thereby reducing ambiguity that may affect the phase difference-based estimation and achieving very accurate direction estimation and beam acquisition.

[0326] The implementation can also be combined with other features (such as positioning techniques) to narrow the AoA / AoD range and provide better beam tracking and / or reduce the ambiguity associated with phase difference AoA / AoD estimation.

[0327] Although this application refers to illustrative embodiments, it is not intended to be limiting. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of this application, will be apparent to those skilled in the art upon reference to this specification. Therefore, the appended claims are intended to cover any such modifications or embodiments.

[0328] Although this application has been described with reference to specific features and embodiments thereof, various modifications and combinations may be made to it without departing from this application. Therefore, the description and drawings are to be considered merely as illustrations of some embodiments of this application as defined by the appended claims, and are intended to cover any and all modifications, variations, combinations, or equivalents falling within the scope of this application. Thus, although this application and its advantages have been described in detail, various changes, substitutions, and alterations may be made herein without departing from the scope of this application as defined by the appended claims. Furthermore, the scope of this application is not limited to the specific embodiments of the processes, machines, products, compositions of matter, components, methods, and steps described in the specification. Those skilled in the art will readily understand from the disclosure of this application that processes, machines, articles of manufacture, compositions of matter, modules, methods, or steps (including those currently existing or later developed) can be used to perform or achieve substantially the same function or result as the corresponding embodiments described herein. Therefore, the scope of the appended claims includes such processes, machines, products, compositions of matter, components, methods, or steps.

[0329] Furthermore, although described primarily in the context of methods and apparatus, other implementations are also contemplated as, for example, processor-executable or computer-executable instructions stored on non-transitory processor-readable or computer-readable media. These media may store programming or instructions to perform any of the various methods consistent with this application.

Claims

1. A method for a wireless communication network in the THz frequency band, characterized by, comprising: receiving, at a first communication device in a wireless communication network, reference signaling from a second communication device in the wireless communication network in two or more beams having a same direction; determining, at the first communication device, a value associated with a direction from the first communication device to the second communication device from which the first communication device receives the reference signaling, the direction having a higher accuracy than an accuracy of a beam width associated with the received reference signaling, wherein the determining comprises determining the value based on a separation of paths using a beam sweep and a time resolution over which the reference signaling is received in the two or more beams having the same direction, and wherein the separation of paths uses a wideband pilot pseudo noise (PN) sequence repeated with a relatively narrow transmit beam; the PN sequence satisfying: an autocorrelation between a PN sequence and a delayed version thereof is a value of 1 or close to 1 when there is no delay; the autocorrelation between the PN sequence and the delayed version thereof is a value of 0 or close to 0 when a delay between the PN sequence and the delayed version thereof is equal to or higher than a chip duration of the PN sequence.

2. The method of claim 1, wherein, the direction comprises a direction of arrival of the reference signaling from the second communication device to the first communication device.

3. The method of claim 1, wherein, the direction comprises a direction of departure of the reference signaling transmission from which the first communication device receives the reference signaling, the method further comprising: transmitting, from the first communication device, signaling indicating a value associated with the direction of departure.

4. The method of claim 3, wherein, the signaling indicating the value associated with the direction of departure is transmitted to the second communication device to enable the second communication device to calculate the direction of departure.

5. The method of claim 3, wherein, the value associated with the direction of departure specifies the direction of departure.

6. The method of claim 5, wherein, further comprising: receiving, at the first communication device, other signaling, wherein the determining comprises calculating the direction of departure based on the reference signaling from the second communication device and the received other signaling.

7. The method of claim 6, wherein, the other signaling comprises signaling indicating one or more of: a beam pattern, the beam width, an antenna configuration, and an antenna structure.

8. The method according to any one of claims 1 to 7, characterized in that, the first communication device comprises a user equipment (UE) and the second communication device comprises a network device in the wireless communication network.

9. The method according to any one of claims 1 to 7, characterized in that, the first communication device comprises a network device in the wireless communication network and the second communication device comprises a UE.

10. The method according to any one of claims 1 to 7, characterized in that, the first communication device comprises a first UE and the second communication device comprises a second UE.

11. The method according to any one of claims 1 to 7, characterized in that, determining the value is further based on one or more of: a phase difference between measurements of the reference signaling received in the two or more beams having the same direction; measurements of the reference signaling received at different times by a single radio frequency (RF) chain; and a beam squint.

12. A processor-readable medium, comprising: storing instructions that, when executed by one or more processors on a first communication device in a wireless communication network, cause the one or more processors to perform the method of any of claims 1-11.

13. A first communication device for a wireless communication network, characterized in that, the first communication device comprises: a receiver; and a transmitter. a processor coupled to the receiver, the processor to perform the method of any of claims 1-11.

14. A method for a wireless communication network in the THz band, characterized in that, comprising: transmitting, at a second communication device, reference signaling to a first communication device in a wireless communication network on two or more beams having a same direction; receiving, at the second communication device, signaling indicating a value determined by the first communication device and associated with a transmission direction of the reference signaling, the first communication device receiving the reference signaling from the transmission direction, the direction having a higher accuracy than an accuracy of a beam width associated with the reference signaling, wherein the value is determined based on a separation of paths using a beam sweep and a time resolution, the reference signaling being received by the first communication device on the two or more beams having the same direction over the paths, and wherein the separation of paths uses a wideband pilot pseudo noise, PN, sequence repeated with a relatively narrow transmission beam; the PN sequence satisfying: an autocorrelation between the PN sequence and a delayed version thereof is a value of 1 or close to 1 when there is no delay; the autocorrelation between the PN sequence and the delayed version thereof is a value of 0 or close to 0 when a delay between the PN sequence and the delayed version thereof is equal to or higher than a chip duration of the PN sequence.

15. The method of claim 14, wherein, the value associated with the transmission direction enables the second communication device to calculate the transmission direction.

16. The method of claim 14, wherein, the value associated with the transmission direction specifies the transmission direction, and wherein the method further comprises transmitting, at the second communication device, further signaling to the first communication device to enable the first communication device to calculate the transmission direction.

17. The method of claim 16, wherein, the further signaling is or includes signaling indicating one or more parameters to be used by the communication device when transmitting the reference signaling.

18. The method of claim 16, wherein, the further signaling is or includes signaling indicating one or more of: a beam pattern, the beam width, an antenna configuration, or an antenna structure.

19. The method according to any one of claims 14 to 18, characterized in that, the second communication device is a network device in the wireless communication network, and the first communication device is a UE.

20. The method of any one of claims 14 to 18, wherein, the second communication device is a UE, and the first communication device is a network device in the wireless communication network.

21. The method of any one of claims 14-18, wherein, the second communication device is a first UE, and the first communication device is a second UE.

22. The method of any one of claims 14-18, wherein, the value is further determined based on one or more of: a phase difference between measurements of the reference signaling received in the two or more beams having the same direction; measurements of the reference signaling received at different times by a single RF chain on the first communication device; a beam squint determined by the first communication device.

23. A processor-readable medium, comprising: storing instructions that, when executed by one or more processors on a second communication device in a wireless communication network, cause the one or more processors to perform the method of any of claims 14-22.

24. A second communication device for a wireless communication network, characterized in that, the second communication device comprising: a transmitter; a processor coupled to the transmitter, the processor to perform the method of any of claims 14-22.

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