Beam training method, apparatus and device applied to near field wideband communication system

Abstract

This invention provides a beam training method, apparatus, and device for near-field broadband communication systems. Applied to a transmitting end, the transmitting end is configured with an antenna array and a time-delay TD element. The method includes: configuring the time delay parameters of the TD element according to a preset scanning strategy. The scanning strategy includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point in different spatial directions; transmitting wavenumber domain codewords on multiple subcarriers based on the time delay parameters, acquiring the received signal from the user end, and determining the corresponding two-dimensional wavenumber domain spectrum; extracting the spectral features of the two-dimensional wavenumber domain spectrum, including the normalized wavenumber width and normalized wavenumber center; calculating the three-dimensional spatial coordinates of the user end based on the spectral features and the physical dimensions of the antenna array; and calculating the near-field beamforming vector based on the three-dimensional spatial coordinates. This invention fully utilizes the frequency differences of multiple carriers and the wavenumber domain spectral features, effectively reducing beam training overhead.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a beam training method, apparatus, and device for near-field broadband communication systems. Background Technology

[0002] With the evolution of 6G wireless communication towards higher frequency bands such as millimeter waves and terahertz, Extremely Large-Scale Multiple-Input Multiple-Output (XL-MIMO) is considered a key technology for improving throughput and compensating for path loss. Due to the significant increase in antenna array aperture and operating frequency, the Rayleigh distance of electromagnetic waves is greatly extended, making it inevitable that XL-MIMO systems need to operate in near-field environments.

[0003] In near-field communication, precise beam training is necessary to find the optimal codeword in order to achieve high-gain beamforming. However, unlike far-field communication, which only requires a one-dimensional angle search, near-field communication introduces a distance variable, causing the search for the optimal codeword to evolve into a two-dimensional joint search of angle and distance. This drastically increases the overhead of beam training.

[0004] In existing technologies, some near-field broadband beamforming methods utilize beam splitting effects and employ beamforming architectures based on time-delay (TD) elements to simultaneously scan multiple angles at a specific distance. However, these methods still rely on exhaustive searches in the distance dimension, resulting in persistently high overall beamforming overhead. Therefore, how to completely overcome the exhaustive limitations of the distance dimension while maintaining high beamforming gain, thereby minimizing the beamforming overhead of near-field broadband systems, has become a pressing technical challenge in this field. Summary of the Invention

[0005] This invention provides a beam training method, apparatus, and device for near-field broadband communication systems, which solves the problem that in the prior art, near-field broadband beam training relies heavily on exhaustive search in the distance dimension, resulting in excessively high beam training overhead.

[0006] This invention provides a beam training method for a near-field broadband communication system, applied at a transmitting end. The transmitting end is configured with an antenna array and a time-delay (TD) element. The TD element is used to apply time-delay control to multiple subcarriers transmitted by the antenna array. The method includes: The delay parameters of the TD element are configured according to a preset scanning strategy. The scanning strategy includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions. Based on the time delay parameter, wavenumber domain codewords are transmitted on multiple subcarriers to obtain the received signal from the user terminal, and the corresponding two-dimensional wavenumber domain spectrum is determined based on the received signal. Extract the spectral features of the two-dimensional wavenumber domain spectrum, the spectral features including the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axis directions; Based on the spectral characteristics and the physical dimensions of the antenna array, the three-dimensional spatial coordinates of the user terminal are calculated, and a near-field beamforming vector is calculated based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

[0007] In some embodiments, configuring the delay parameters of the TD element according to a preset scanning strategy includes: Obtain the number of the first antenna elements of the antenna array along the horizontal direction. and the number of second antenna elements along the vertical direction ; Configure the horizontal delay parameters of the TD element and vertical delay parameters So that the first ratio Second ratio One of the ratios falls outside the preset normalized wavenumber interval [-1, 1], and the other ratio falls within the normalized wavenumber interval [-1, 1].

[0008] In some embodiments, determining the corresponding two-dimensional wavenumber domain spectrum based on the received signal includes: Based on the received signal, obtain the complete initial two-dimensional wavenumber domain spectrum; The initial two-dimensional wavenumber domain spectrum is filtered based on a preset amplitude threshold to obtain the two-dimensional wavenumber domain spectrum.

[0009] In some embodiments, the formula for calculating the two-dimensional wavenumber domain spectrum is as follows: ; in, Let w represent the two-dimensional wavenumber domain spectrum, and w represent the wavenumber domain. This represents the initial two-dimensional wavenumber domain spectrum. This indicates the wavenumber index along the horizontal direction of the antenna array. This indicates the wavenumber index along the vertical direction of the antenna array. Indicates subcarrier The bottom-aligned normalized wavenumber along the horizontal direction. Indicates subcarrier The bottom-aligned normalized wavenumber along the vertical direction. This represents the preset amplitude threshold. It represents the absolute value of the maximum signal amplitude in the initial two-dimensional wavenumber domain spectrum.

[0010] In some embodiments, the spectral features include: normalized horizontal wavenumber width and normalized horizontal wavenumber center, and normalized vertical wavenumber width and normalized vertical wavenumber center. The extraction of spectral features from the two-dimensional wavenumber domain spectrum includes: Based on the two-dimensional wavenumber domain spectrum, the effective signal region is determined, and the closed boundary of the effective signal region is determined. Under a fixed normalized vertical wavenumber, based on the closed boundary, the horizontal span of the effective signal region along the horizontal wavenumber axis is measured, the horizontal span is taken as the normalized horizontal wavenumber width, and the midpoint of the horizontal span is taken as the normalized horizontal wavenumber center. Under a fixed normalized horizontal wavenumber, based on the closed boundary, the vertical span of the effective signal region along the vertical wavenumber axis is measured, the vertical span is taken as the normalized vertical wavenumber width, and the midpoint of the vertical span is taken as the normalized vertical wavenumber center.

[0011] In some embodiments, the formula for calculating the three-dimensional spatial coordinates of the user terminal is as follows: ; ; ; ; ; ; ; in, This represents the three-dimensional spatial coordinates of the user terminal. Represents the coordinate components along the X-axis. This represents the coordinate components along the Y-axis. Represents the coordinate components along the Z-axis; This indicates the horizontal physical size of the antenna array. This indicates the vertical physical dimension of the antenna array. , , , All are intermediate geometric parameters; This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber width measured below, This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber center measured below; This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber width measured below, This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber center measured below; and As auxiliary parameters, , , This is an indicator function.

[0012] In some embodiments, determining the near-field beamforming vector based on the three-dimensional spatial coordinates includes: Based on the three-dimensional spatial coordinates of the user terminal and the coordinates of each antenna element in the antenna array, calculate the physical distance between each antenna element and the user terminal; The near-field beamforming vector is calculated based on the physical distance and the wave number corresponding to each subcarrier.

[0013] The present invention also provides a beam training device for a near-field broadband communication system, applied at a transmitting end, wherein the transmitting end is configured with an antenna array and a time delay (TD) element, the TD element being used to apply time delay control to multiple subcarriers transmitted by the antenna array, and the device comprising: The configuration unit is used to configure the delay parameters of the TD element according to a preset scanning strategy. The scanning strategy includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions. The determining unit is configured to transmit wavenumber domain codewords on multiple subcarriers based on the time delay parameters, acquire the received signal from the user terminal, and determine the corresponding two-dimensional wavenumber domain spectrum based on the received signal; The feature extraction unit is used to extract the spectral features of the two-dimensional wavenumber domain spectrum, the spectral features including the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axis directions. The computing unit is used to calculate the three-dimensional spatial coordinates of the user terminal based on the spectral features and the physical dimensions of the antenna array, and to calculate the near-field beamforming vector based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

[0014] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the beam training method for near-field broadband communication systems as described above.

[0015] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the beam training method for near-field broadband communication systems as described above.

[0016] This invention provides a beam training method, apparatus, and device for near-field broadband communication systems. By configuring the delay parameters of TD elements according to a preset scanning strategy, the beams on different subcarriers point in different spatial directions when the transmitter sends the same wavenumber domain codeword. Based on the delay parameters, wavenumber domain codewords are sent on multiple subcarriers to acquire the received signal from the user end and determine the corresponding two-dimensional wavenumber domain spectrum. Spectral features of the two-dimensional wavenumber domain spectrum are extracted, including the normalized wavenumber width and normalized wavenumber center along different coordinate axes. Based on the spectral features and the physical dimensions of the antenna array, the three-dimensional spatial coordinates of the user end are calculated. The near-field beamforming vector is then calculated based on these three-dimensional spatial coordinates. This fully utilizes the frequency differences of multiple carriers and the wavenumber domain spectral features, enabling direct calculation of the user end's three-dimensional coordinates. It completely breaks the exhaustive limitation of the distance dimension, effectively reducing beam training overhead and significantly improving the link establishment efficiency and communication quality of near-field broadband communication while maintaining high beamforming gain. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a beam training method for near-field broadband communication systems provided in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the boundary of the two-dimensional wavenumber domain spectrum provided in an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the boundary of the antenna array provided in an embodiment of the present invention.

[0021] Figure 4 This is one of the simulation results of the beam training method for near-field broadband communication systems provided in the embodiments of the present invention.

[0022] Figure 5 This is the second schematic diagram of the simulation results of the beam training method for near-field broadband communication systems provided in this embodiment of the invention.

[0023] Figure 6This is a schematic diagram of the beam training device for near-field broadband communication systems provided in an embodiment of the present invention.

[0024] Figure 7 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] Figure 1 This is a flowchart illustrating a beam training method for a near-field broadband communication system provided in an embodiment of the present invention. Figure 1 As shown, a beam training method for a near-field broadband communication system is provided. The method is applied to a transmitting end, which is configured with an antenna array and a time-delay (TD) element. The TD element is used to apply time delay control to multiple subcarriers transmitted by the antenna array. The method includes the following steps: steps 110, 120, 130, and 140. These steps are merely one possible implementation of the invention.

[0027] In this embodiment of the invention, the near-field broadband communication system can be an ultra-large-scale multiple-input multiple-output (XL-MIMO) system employing Orthogonal Frequency Division Multiplexing (OFDM) technology, operating in high-frequency bands such as millimeter waves or terahertz. The transmitting end can be network-side equipment such as a base station or access point. The antenna array is preferably a uniform planar array (UPA), composed of multiple antenna elements arranged horizontally and vertically, with defined physical dimensions. The time delay (TD) element is a hardware unit capable of applying a controllable time delay to the signal, integrated into the radio frequency link of the transmitting end. The multiple subcarriers are multiple orthogonal frequency channels generated under OFDM modulation.

[0028] Step 110: Configure the delay parameters of the TD element according to the preset scanning strategy. The scanning strategy includes: when the transmitter sends the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions.

[0029] Specifically, this step aims to utilize the characteristics of delay elements to achieve a frequency-dependent beam scanning, i.e., beam splitting. A wavenumber domain codeword is a pre-defined codeword vector used to form a specific phase distribution on the antenna array. In traditional phase shifter architectures, the same codeword generates beams pointing in the same spatial direction on all subcarriers. However, in this embodiment of the invention, by configuring specific delay parameters for the TD element, a fixed delay can produce different phase shifts for subcarrier signals of different frequencies, since the phase shift is proportional to the frequency. This frequency-dependent phase difference acts on the entire antenna array, ultimately resulting in a greater angle of beam deviation from the original direction for higher-frequency subcarriers when transmitting the same wavenumber domain codeword. In this way, only one codeword needs to be transmitted to achieve synchronous detection of multiple directions in space on multiple subcarriers within the entire operating bandwidth.

[0030] Optionally, at frequency Next, the The frequency domain response of each TD element is determined by Given, among which Indicates the first Adjustable delay of each TD element. During beam training, Configured as follows: ; in, and These represent the sending edge. shaft and Antenna element index of the axis, The spacing between half-wavelength antennas. The horizontal delay parameter of the TD element. The vertical delay parameter for the TD element. This indicates the number of the first antenna elements along the horizontal direction. This indicates the number of second antenna elements along the vertical direction.

[0031] Step 120: Based on the time delay parameter, transmit wavenumber domain codewords on multiple subcarriers, obtain the received signal from the user terminal, and determine the corresponding two-dimensional wavenumber domain spectrum based on the received signal.

[0032] In this step, the transmitting end transmits multiple subcarrier signals carrying the same wavenumber codeword into space via an antenna array, according to the configured delay parameters. The user end, such as a mobile phone or other terminal device, receives these signals and can measure and report the received signal strength information on each subcarrier. The received signal can also be channel state information obtained by the transmitting end through channel sounding. Since the beams of different subcarriers point in different directions, the received signal strength of each subcarrier reflects the channel response in the corresponding spatial direction. The two-dimensional wavenumber spectrum is a representation of the channel response in the spatial frequency domain. By collecting the received signals on all subcarriers and mapping them to a two-dimensional coordinate system composed of normalized wavenumbers, a complete or partial two-dimensional wavenumber spectrum can be constructed.

[0033] Alternatively, the wavenumber field codeword can be represented as: ; in, Represents wavenumber field codewords, This indicates the total number of antenna elements in the antenna array. Indicates the first Effective normalized wavenumber generated under each subcarrier It is the imaginary unit.

[0034] It is understandable that by using a wavenumber codeword to detect the received signal at different angles on different subcarriers, wavenumber spectral information in multiple directions can be obtained, thus a complete two-dimensional wavenumber spectrum can be obtained by sending a small number of wavenumber codewords.

[0035] Step 130: Extract the spectral features of the two-dimensional wavenumber domain spectrum. The spectral features include the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axes.

[0036] Alternatively, the two-dimensional wavenumber domain spectrum can be represented as a region of a specific shape surrounded by four semi-elliptical boundaries.

[0037] The goal of this step is to extract quantitative features from the geometry of the two-dimensional wavenumber domain spectrum. These spectral features specifically include the normalized horizontal wavenumber width and center, as well as the normalized vertical wavenumber width and center. For example, to extract the normalized horizontal wavenumber width and center, the maximum horizontal span of the spectral energy region can be measured at a fixed normalized vertical wavenumber value as the width, and the midpoint of this span can be calculated as the center. By measuring multiple different vertical wavenumber positions, precise quantitative information about the geometry of the two-dimensional wavenumber domain spectrum can be obtained.

[0038] Step 140: Based on the spectral characteristics and the physical dimensions of the antenna array, calculate the three-dimensional spatial coordinates of the user terminal, and calculate the near-field beamforming vector based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

[0039] This step is crucial for user positioning and final beamforming. A precise closed-form mathematical relationship exists between spectral features, the user's three-dimensional spatial coordinates, and the physical dimensions of the antenna array. Therefore, by substituting the extracted spectral feature values ​​and the known antenna array physical dimensions into a pre-defined system of equations, the user's three-dimensional spatial coordinates, including its range, azimuth, and elevation angles, can be directly calculated. This completely avoids the exhaustive search for the range dimension found in traditional methods. After obtaining the precise three-dimensional coordinates of the user, the transmitter can calculate a near-field beamforming vector that accurately focuses signal energy to that spatial point and apply this vector to subsequent data communication with the user, thereby achieving high-gain, reliable transmission.

[0040] In this embodiment of the invention, by configuring the delay parameters of the TD element according to a preset scanning strategy, the beams on different subcarriers point in different spatial directions when the transmitting end transmits the same wavenumber domain codeword. Based on the delay parameters, wavenumber domain codewords are transmitted on multiple subcarriers to obtain the received signal from the user end and determine the corresponding two-dimensional wavenumber domain spectrum. The spectral features of the two-dimensional wavenumber domain spectrum are extracted, including the normalized wavenumber width and normalized wavenumber center along different coordinate axes. Based on the spectral features and the physical dimensions of the antenna array, the three-dimensional spatial coordinates of the user end are calculated, and the near-field beamforming vector is calculated based on the three-dimensional spatial coordinates. This fully utilizes the frequency differences of multiple carriers and the wavenumber domain spectral features, realizing the direct calculation and solution of the three-dimensional coordinates of the user end. It completely breaks the exhaustive limitation of the distance dimension, effectively reduces beam training overhead, and significantly improves the link establishment efficiency and communication quality of near-field broadband communication while maintaining high beamforming gain.

[0041] In some embodiments, configuring the delay parameters of the TD element according to a preset scanning strategy includes: Obtain the number of the first antenna elements in the horizontal direction of the antenna array. and the number of second antenna elements along the vertical direction ; Configure the horizontal delay parameters of the TD element and vertical delay parameters So that the first ratio Second ratio One of the ratios falls outside the preset normalized wavenumber interval [-1, 1], while the other ratio falls within the normalized wavenumber interval [-1, 1].

[0042] It should be noted that by setting the TD parameter and Send a wavenumber field codeword , No. The amplitude of the received signal obtained from each subcarrier can be considered as follows, without considering noise: The numerical value of the upper wavenumber domain spectrum. Therefore, for a given... For the UPA of antenna elements, appropriate TD parameters can be configured. and Let the parameters It falls outside the feasible range, and This falls within the feasible range, meaning that M subcarriers can acquire the same... Multiple The wavenumber domain spectral information, then proceed with... The complete wavenumber domain spectrum can be obtained in one cycle, greatly reducing the overhead required.

[0043] In some embodiments, determining the corresponding two-dimensional wavenumber domain spectrum based on the received signal includes: Based on the received signal, obtain the complete initial two-dimensional wavenumber domain spectrum; The initial two-dimensional wavenumber domain spectrum is filtered based on a preset amplitude threshold to obtain the two-dimensional wavenumber domain spectrum.

[0044] Optionally, the formula for calculating the received signal is: ; .

[0045] In some embodiments, the formula for calculating the two-dimensional wavenumber domain spectrum is as follows: ; in, Let w represent the two-dimensional wavenumber field spectrum, and w represent the wavenumber field. Represents the initial two-dimensional wavenumber field spectrum. This indicates the wavenumber index along the horizontal direction of the antenna array. Indicates the horizontal direction. This indicates the wavenumber index along the vertical direction of the antenna array. Indicates the vertical direction. Indicates subcarrier The bottom-aligned normalized wavenumber along the horizontal direction. Indicates subcarrier The bottom-aligned normalized wavenumber along the vertical direction. This indicates the preset amplitude threshold. It represents the absolute value of the maximum signal amplitude in the initial two-dimensional wavenumber domain spectrum.

[0046] Optionally, subcarrier The formula for calculating the beam gain generated by TD beamforming is as follows: ; Alternatively, the formula for calculating the normalized wavenumber is as follows: ; in, A periodic index representing the horizontal direction. Represents a periodic index in the vertical direction. Indicates subcarrier The normalized frequency factor.

[0047] Assume the wavenumber direction of the wavenumber domain codeword aligned with the center subcarrier is as follows: and ,but ,in It is a positive integer. For any... , The entire potential wavenumber range is limited to Between. The range corresponding to the wavenumber index is: .

[0048] To ensure coverage of the entire potential wavenumber range across all subcarriers, the following constraints must be met: ; .

[0049] To ensure the above full coverage is an effective The solution is: ; in This represents the floor function. Indicates the center carrier frequency. Indicates the highest frequency. Indicates the lowest frequency. Indicates bandwidth.

[0050] Optionally, the first The frequency of each subcarrier can be expressed as: ; in, This indicates the total number of subcarriers.

[0051] Optionally, in the Under the subcarrier, the ... The channel between an antenna element and the user terminal can be represented as: ; ; ; in, Indicates complex gain. Represents the speed of light. Indicates the center wavelength. Indicates the first The distance between each antenna element and the user terminal.

[0052] The user's three-dimensional spatial coordinates are: ; in , and These represent the distance, elevation angle, and azimuth angle of the user terminal, respectively. Therefore, the first... The distance between each antenna and the user terminal is determined by... Given, among which It is the first The coordinates of each antenna element.

[0053] In a carrier frequency of In narrowband systems, using a phase shifter (PS) beamforming framework and ignoring the effects of noise, two-dimensional wavenumber domain spectra can be obtained by beam scanning using wavenumber domain codewords. ,Right now: ; in, Represents the wavenumber field codeword.

[0054] A two-dimensional wavenumber domain spectrum can be understood as the received signal matrix obtained by beam scanning using codewords in a noise-free environment. Among these, The wavenumber domain codeword generated for the phase shifter, its first... The formula for calculating each element is as follows: ; in, and Indicates along shaft and The normalized wavenumber of the axis. support set for wavenumber domain The size, and Represented as: ; It collects the wavenumber indices corresponding to all transmitted wave components. Therefore, the training overhead required to obtain the complete wavenumber spectrum using wavenumber domain codewords in a narrowband system is... .

[0055] In some embodiments, the spectral features include: normalized horizontal wavenumber width and normalized horizontal wavenumber center, and normalized vertical wavenumber width and normalized vertical wavenumber center. Extracting spectral features from a two-dimensional wavenumber domain spectrum, including: Based on the two-dimensional wavenumber domain spectrum, the effective signal region is determined, and the closed boundary of the effective signal region is also determined. Under a fixed normalized vertical wavenumber, based on a closed boundary, the horizontal span of the effective signal region along the horizontal wavenumber axis is measured, the horizontal span is taken as the normalized horizontal wavenumber width, and the midpoint of the horizontal span is taken as the normalized horizontal wavenumber center. Under a fixed normalized horizontal wavenumber, based on a closed boundary, the vertical span of the effective signal region along the vertical wavenumber axis is measured, and the vertical span is taken as the normalized vertical wavenumber width, with the midpoint of the vertical span taken as the normalized vertical wavenumber center.

[0056] In some embodiments, the formula for calculating the three-dimensional spatial coordinates of the user terminal is as follows: ; ; ; ; ; ; ; in, Represents the three-dimensional spatial coordinates of the user terminal. Represents the coordinate components along the X-axis. This represents the coordinate components along the Y-axis. Represents the coordinate components along the Z-axis; This indicates the horizontal physical dimensions of the antenna array. This indicates the vertical physical dimensions of the antenna array. , , , All are intermediate geometric parameters; This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber width measured below, This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber center measured below; This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber width measured below, This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber center measured below; and As auxiliary parameters, , , This is an indicator function.

[0057] Optionally, the formula for calculating the normalized horizontal wavenumber width is as follows: ; The formula for calculating the normalized horizontal wavenumber center is as follows: ; The formula for calculating the normalized vertical wavenumber width is as follows: ; The formula for calculating the normalized vertical wavenumber center is as follows: .

[0058] Figure 2 This is a schematic diagram of the boundary of a two-dimensional wavenumber domain spectrum provided in an embodiment of the present invention. Figure 2 As shown, the boundary of the two-dimensional wavenumber domain spectrum is characterized by four different semi-ellipses.

[0059] Figure 3 This is a schematic diagram of the boundary of an antenna array provided in an embodiment of the present invention. Figure 3 As shown, the antenna array is a UPA, which has four physical boundaries. The boundaries of the two-dimensional wavenumber domain spectrum are determined by the spatial location of the user terminal and the four physical boundaries of the UPA.

[0060] Each point on boundary 1 of the two-dimensional wavenumber domain spectrum corresponds to a location from the user end. To the edge of the antenna array The direction of spread, among which .make Let be the normalized wavenumber vector, where . Each point on All satisfy the directional constraints imposed by this geometric relationship, expressed as: ; in, It is a normalization operator.

[0061] The components on and It can be explicitly expressed as: ; ; Spatial coordinates can be obtained The expression is: ; By removing the finite range constraint, i.e. It can be deduced that Figure 2 The closed-form expression for the semiellipse 1 shown is as follows: ; in, This is the sign function. Here, the geometric relationship between the user terminal and the antenna array determines the location of the boundary enclosed by the ellipse, which is determined by the constraints. Valid definition. Following the same steps, the expressions for the remaining three semi-ellipses are as follows: .

[0062] In some embodiments, determining the near-field beamforming vector based on three-dimensional spatial coordinates includes: Based on the three-dimensional spatial coordinates of the user terminal and the coordinates of each antenna element in the antenna array, calculate the physical distance between each antenna element and the user terminal. The near-field beamforming vector is calculated based on the physical distance and the wave number corresponding to each subcarrier.

[0063] Optionally, the final transmitted beam is based on TD elements. The Each element can be represented as: ; .

[0064] To verify the performance of the beam training method for near-field broadband communication systems provided in this embodiment of the invention, a uniform linear array is used as an example. The proposed method is compared with far-field broadband beam scanning and near-field broadband beam scanning to obtain simulation results.

[0065] Figure 4 This is one of the simulation results of the beam training method applied to a near-field broadband communication system provided in an embodiment of the present invention. Figure 4 As shown, this paper compares the achievable transmission rates of the proposed method, the far-field broadband beam scanning method, and the near-field broadband beam scanning method at different communication distances.

[0066] Specifically, the simulation experiment was conducted in a typical near-field ultra-large-scale multiple-input multiple-output (UMI) communication scenario. Figure 4As can be seen, the transmission rate of the method proposed in this invention is significantly better than the two comparative methods across all test distances. This is because the embodiments of this invention obtain the three-dimensional spatial coordinates of the user end through direct calculation, thereby generating a highly focused near-field beamforming vector and maximizing beam gain. In contrast, although the traditional near-field broadband beam scanning method considers the distance dimension, it relies on exhaustive search within a preset codebook, and the beam found may not be optimal, and the overhead is huge. The far-field broadband beam scanning method completely ignores the influence of the distance dimension, resulting in severe beam defocusing in the near field, leading to gain loss, and therefore its performance is the worst.

[0067] Figure 5 This is the second schematic diagram illustrating the simulation results of the beam training method applied to a near-field broadband communication system provided in an embodiment of the present invention. Figure 5 The diagram illustrates a comparison of the achievable transmission rates of the three methods as a function of training overhead. Training overhead typically refers to the number of pilot symbols or time resources used for beam training.

[0068] from Figure 5 As can be clearly seen, the method proposed in this invention can quickly reach its performance ceiling with extremely low training overhead, and this performance ceiling is far higher than that of the other two methods. The fundamental reason is that the embodiments of this invention directly solve for the coordinates of the user end by extracting wavenumber domain spectral features, completely breaking the limitation of exhaustive scanning of angle and distance dimensions, thus achieving high training efficiency. In contrast, far-field and near-field broadband beam scanning methods require a large number of training codewords to scan different angles or combinations of angles and distances one by one. Therefore, the training overhead increases sharply with the requirement of scanning accuracy in order to gradually improve its transmission rate.

[0069] Based on the above results, it can be seen that the method proposed in the embodiments of the present invention can achieve high transmission performance with lower training overhead.

[0070] The beam training device for near-field broadband communication systems provided in the embodiments of the present invention is described below. The beam training device for near-field broadband communication systems described below can be referred to in correspondence with the beam training method for near-field broadband communication systems described above.

[0071] Figure 6 This is a schematic diagram of the beam training device for a near-field broadband communication system provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the device 600 is applied to a transmitting end, which is configured with an antenna array and a time-delay (TD) element. The TD element is used to apply time-delay control to multiple subcarriers transmitted by the antenna array. The device 600 includes: The configuration unit 610 is used to configure the delay parameters of the TD element according to a preset scanning strategy. The scanning strategy includes: when the transmitter transmits the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions. The determining unit 620 is used to transmit wavenumber domain codewords on multiple subcarriers based on time delay parameters, obtain the received signal from the user end, and determine the corresponding two-dimensional wavenumber domain spectrum based on the received signal; The feature extraction unit 630 is used to extract the spectral features of the two-dimensional wavenumber domain spectrum. The spectral features include the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axis directions. The computing unit 640 is used to calculate the three-dimensional spatial coordinates of the user terminal based on spectral characteristics and the physical dimensions of the antenna array, and to calculate the near-field beamforming vector based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

[0072] Optionally, the delay parameters of the TD element are configured according to a preset scanning strategy, including: Obtain the number of the first antenna elements in the horizontal direction of the antenna array. and the number of second antenna elements along the vertical direction ; Configure the horizontal delay parameters of the TD element and vertical delay parameters So that the first ratio Second ratio One of the ratios falls outside the preset normalized wavenumber interval [-1, 1], while the other ratio falls within the normalized wavenumber interval [-1, 1].

[0073] Optionally, determining the corresponding two-dimensional wavenumber domain spectrum based on the received signal includes: Based on the received signal, obtain the complete initial two-dimensional wavenumber domain spectrum; The initial two-dimensional wavenumber domain spectrum is filtered based on a preset amplitude threshold to obtain the two-dimensional wavenumber domain spectrum.

[0074] Optionally, the formula for calculating the two-dimensional wavenumber domain spectrum is as follows: ; in, Let w represent the two-dimensional wavenumber field spectrum, and w represent the wavenumber field. Represents the initial two-dimensional wavenumber field spectrum. This indicates the wavenumber index along the horizontal direction of the antenna array. This indicates the wavenumber index along the vertical direction of the antenna array. Indicates subcarrier The bottom-aligned normalized wavenumber along the horizontal direction. Indicates subcarrier The bottom-aligned normalized wavenumber along the vertical direction. This indicates the preset amplitude threshold. It represents the absolute value of the maximum signal amplitude in the initial two-dimensional wavenumber domain spectrum.

[0075] Optionally, the spectral features include: normalized horizontal wavenumber width and normalized horizontal wavenumber center, and normalized vertical wavenumber width and normalized vertical wavenumber center; Extracting spectral features from a two-dimensional wavenumber domain spectrum, including: Based on the two-dimensional wavenumber domain spectrum, the effective signal region is determined, and the closed boundary of the effective signal region is also determined. Under a fixed normalized vertical wavenumber, based on a closed boundary, the horizontal span of the effective signal region along the horizontal wavenumber axis is measured, the horizontal span is taken as the normalized horizontal wavenumber width, and the midpoint of the horizontal span is taken as the normalized horizontal wavenumber center. Under a fixed normalized horizontal wavenumber, based on a closed boundary, the vertical span of the effective signal region along the vertical wavenumber axis is measured, and the vertical span is taken as the normalized vertical wavenumber width, with the midpoint of the vertical span taken as the normalized vertical wavenumber center.

[0076] Optionally, the formula for calculating the three-dimensional spatial coordinates on the user end is as follows: ; ; ; ; ; ; ; in, Represents the three-dimensional spatial coordinates of the user terminal. Represents the coordinate components along the X-axis. This represents the coordinate components along the Y-axis. Represents the coordinate components along the Z-axis; This indicates the horizontal physical dimensions of the antenna array. This indicates the vertical physical dimensions of the antenna array. , , , All are intermediate geometric parameters; This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber width measured below, This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber center measured below; This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber width measured below, This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber center measured below; and As auxiliary parameters, , , This is an indicator function.

[0077] Optionally, the near-field beamforming vector is determined based on three-dimensional spatial coordinates, including: Based on the three-dimensional spatial coordinates of the user terminal and the coordinates of each antenna element in the antenna array, calculate the physical distance between each antenna element and the user terminal. The near-field beamforming vector is calculated based on the physical distance and the wave number corresponding to each subcarrier.

[0078] It should be noted that the beam training device for near-field broadband communication systems provided in this embodiment of the invention can implement all the method steps implemented in the above-described beam training method embodiment for near-field broadband communication systems, and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0079] Figure 7 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present invention, such as... Figure 7As shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communications bus 740, wherein the processor 710, the communications interface 720, and the memory 730 communicate with each other through the communications bus 740. The processor 710 can call logic instructions in the memory 730 to execute a beam training method applied to a near-field broadband communication system. This method is applied to a transmitter, which is configured with an antenna array and a time delay (TD) element. The TD element is used to apply time delay control to multiple subcarriers transmitted by the antenna array. The method includes: when the transmitter transmits the same wavenumber domain codeword, the beams on different subcarriers point in different spatial directions; based on the time delay parameters, the transmitter transmits the wavenumber domain codeword on multiple subcarriers, acquires the received signal from the user end, and determines the corresponding two-dimensional wavenumber domain spectrum based on the received signal; extracts the spectral features of the two-dimensional wavenumber domain spectrum, including the normalized wavenumber width and normalized wavenumber center along different coordinate axes of the two-dimensional wavenumber domain spectrum; calculates the three-dimensional spatial coordinates of the user end based on the spectral features and the physical dimensions of the antenna array; calculates the near-field beamforming vector based on the three-dimensional spatial coordinates; and uses the near-field beamforming vector for data communication with the user end.

[0080] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0081] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the beam training method for a near-field broadband communication system provided by the methods described above. This method is applied to a transmitting end, which is configured with an antenna array and a time delay (TD) element. The TD element is used to apply time delay control to multiple subcarriers transmitted by the antenna array. The method includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point in different spatial directions; based on the time delay parameters, the wavenumber domain codeword is transmitted on multiple subcarriers to obtain the received signal from the user end; based on the received signal, the corresponding two-dimensional wavenumber domain spectrum is determined; the spectral features of the two-dimensional wavenumber domain spectrum are extracted, including the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axes; based on the spectral features and the physical dimensions of the antenna array, the three-dimensional spatial coordinates of the user end are calculated; based on the three-dimensional spatial coordinates, a near-field beamforming vector is calculated; the near-field beamforming vector is used for data communication with the user end.

[0082] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0083] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A beam training method for near-field broadband communication systems, characterized in that, Applied to a transmitting end, the transmitting end is configured with an antenna array and a time-delay (TD) element, the TD element being used to apply time-delay control to multiple subcarriers transmitted by the antenna array, the method comprising: The delay parameters of the TD element are configured according to a preset scanning strategy. The scanning strategy includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions. Based on the time delay parameter, wavenumber domain codewords are transmitted on multiple subcarriers to obtain the received signal from the user terminal, and the corresponding two-dimensional wavenumber domain spectrum is determined based on the received signal. Extract the spectral features of the two-dimensional wavenumber domain spectrum, the spectral features including the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axis directions; Based on the spectral characteristics and the physical dimensions of the antenna array, the three-dimensional spatial coordinates of the user terminal are calculated, and a near-field beamforming vector is calculated based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

2. The beam training method for near-field broadband communication systems according to claim 1, characterized in that, The step of configuring the delay parameters of the TD element according to a preset scanning strategy includes: Obtain the number of the first antenna elements of the antenna array along the horizontal direction. and the number of second antenna elements along the vertical direction ; Configure the horizontal delay parameters of the TD element and vertical delay parameters So that the first ratio Second ratio One of the ratios falls outside the preset normalized wavenumber interval [-1, 1], and the other ratio falls within the normalized wavenumber interval [-1, 1].

3. The beam training method for near-field broadband communication systems according to claim 1, characterized in that, Determining the corresponding two-dimensional wavenumber domain spectrum based on the received signal includes: Based on the received signal, obtain the complete initial two-dimensional wavenumber domain spectrum; The initial two-dimensional wavenumber domain spectrum is filtered based on a preset amplitude threshold to obtain the two-dimensional wavenumber domain spectrum.

4. The beam training method for near-field broadband communication systems according to claim 3, characterized in that, The formula for calculating the two-dimensional wavenumber domain spectrum is as follows: ； in, Let w represent the two-dimensional wavenumber domain spectrum, and w represent the wavenumber domain. This represents the initial two-dimensional wavenumber domain spectrum. This indicates the wavenumber index along the horizontal direction of the antenna array. This indicates the wavenumber index along the vertical direction of the antenna array. Indicates subcarrier The bottom-aligned normalized wavenumber along the horizontal direction. Indicates subcarrier The bottom-aligned normalized wavenumber along the vertical direction. This represents the preset amplitude threshold. It represents the absolute value of the maximum signal amplitude in the initial two-dimensional wavenumber domain spectrum.

5. The beam training method for near-field broadband communication systems according to claim 1, characterized in that, The spectral features include: normalized horizontal wavenumber width and normalized horizontal wavenumber center, and normalized vertical wavenumber width and normalized vertical wavenumber center. The extraction of spectral features from the two-dimensional wavenumber domain spectrum includes: Based on the two-dimensional wavenumber domain spectrum, the effective signal region is determined, and the closed boundary of the effective signal region is determined. Under a fixed normalized vertical wavenumber, based on the closed boundary, the horizontal span of the effective signal region along the horizontal wavenumber axis is measured, the horizontal span is taken as the normalized horizontal wavenumber width, and the midpoint of the horizontal span is taken as the normalized horizontal wavenumber center. Under a fixed normalized horizontal wavenumber, based on the closed boundary, the vertical span of the effective signal region along the vertical wavenumber axis is measured, the vertical span is taken as the normalized vertical wavenumber width, and the midpoint of the vertical span is taken as the normalized vertical wavenumber center.

6. The beam training method for near-field broadband communication systems according to claim 5, characterized in that, The formula for calculating the three-dimensional spatial coordinates of the user terminal is as follows: ； ； ； ； ； ； ； in, This represents the three-dimensional spatial coordinates of the user terminal. Represents the coordinate components along the X-axis. This represents the coordinate components along the Y-axis. Represents the coordinate components along the Z-axis; This indicates the horizontal physical size of the antenna array. This indicates the vertical physical dimension of the antenna array. , , , All are intermediate geometric parameters; This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber width measured below, This indicates that at a fixed normalized vertical wavenumber The normalized horizontal wavenumber center measured below; This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber width measured below, This indicates the wavenumber at a fixed normalized level. The normalized vertical wavenumber center measured below; and As auxiliary parameters, , , This is an indicator function.

7. The beam training method for near-field broadband communication systems according to claim 1, characterized in that, The determination of the near-field beamforming vector based on the three-dimensional spatial coordinates includes: Based on the three-dimensional spatial coordinates of the user terminal and the coordinates of each antenna element in the antenna array, calculate the physical distance between each antenna element and the user terminal; The near-field beamforming vector is calculated based on the physical distance and the wave number corresponding to each subcarrier.

8. A beam training device for use in a near-field broadband communication system, characterized in that, Applied to a transmitting end, the transmitting end is configured with an antenna array and a time-delay (TD) element, the TD element being used to apply time-delay control to multiple subcarriers transmitted by the antenna array, the device comprising: The configuration unit is used to configure the delay parameters of the TD element according to a preset scanning strategy. The scanning strategy includes: when the transmitting end transmits the same wavenumber domain codeword, the beams on different subcarriers point to different spatial directions. The determining unit is configured to transmit wavenumber domain codewords on multiple subcarriers based on the time delay parameters, acquire the received signal from the user terminal, and determine the corresponding two-dimensional wavenumber domain spectrum based on the received signal; The feature extraction unit is used to extract the spectral features of the two-dimensional wavenumber domain spectrum, the spectral features including the normalized wavenumber width and normalized wavenumber center of the two-dimensional wavenumber domain spectrum along different coordinate axis directions. The computing unit is used to calculate the three-dimensional spatial coordinates of the user terminal based on the spectral features and the physical dimensions of the antenna array, and to calculate the near-field beamforming vector based on the three-dimensional spatial coordinates. The near-field beamforming vector is used for data communication with the user terminal.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the beam training method for near-field broadband communication systems as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the beam training method for near-field broadband communication systems as described in any one of claims 1 to 7.

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