Beamforming transceiver apparatus and method
By combining multi-antenna feeder arrays and reconstructible intelligent surfaces in future wireless networks, generalized feature vectors are generated using the transmission matrix T, and beamforming problems under mmWave and sub-terahertz technologies are solved, achieving high-gain narrow beam generation and low-power, lightweight equipment design.
Patent Information
- Application Number
- CN202280100906.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-10
- Publication Date
- 2025-05-16
AI Technical Summary
In future wireless networks (6G), communication channels of millimeter-wave and sub-terahertz (sub-THz) technologies are very sparse, making it difficult to achieve effective beamforming, especially in the case of non-line-of-sight paths.
Using a method of combining a multi-antenna feeder array and a reconstructible intelligent surface (RIS), the transmission relationship between the multi-antenna feeder array and RIS is described through the transmission matrix T, and a generalized feature vector is generated for the design of a beamforming precoder.
It realizes the generation of high-gain narrow beams with very small sidelobes, with lower power consumption, fewer hardware components, and more lightweight and reliable equipment, suitable for single-pulse angle tracking and wide-angle beam generation.
Smart Images
Figure CN120019578A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to communication technology, and more particularly to a beamforming transceiver device and method, especially for wireless communication. Background Art
[0002] Applications that require large bandwidths, such as extended reality (XR), digital twins, haptic technology, etc., are driving research into future wireless networks (often referred to as 6G) towards new, higher bandwidths, such as millimeter-wave (mmWave) and sub-teraHertz (sub-THz) technologies. However, due to large isotropic propagation losses in free space, large absorption in obstructions, and the inability to go around corners by diffraction, mmWave / sub-THz communication channels are very sparse, with line of sight (LOS) paths being the main component. To increase range coverage, spatial focusing (often referred to as beamforming) must be targeted to the desired communication target, e.g., user equipment (UE). Such ultra-high gain beams can be formed by collecting electromagnetic (EM) radiation from a smaller active multi-antenna feeder (AMAF) over a larger aperture. Such large apertures can be created using discrete array elements that achieve spatial sampling, which also allows electronic steering of pencil beams. This approach, known as reflectarray with over-the-air (OTA) beamforming, is well known and has been extensively studied.
[0003] Recently, with the emergence of reconfigurable intelligent surfaces (RIS; sometimes also called reflective or transmissive smart surfaces), a new generation of reflective arrays with electronically controlled steering capabilities has been proposed. Summary of the invention
[0004] An object of the present disclosure is to provide an improved beamforming transceiver device and method, especially for wireless communications.
[0005] The above and other objects are achieved by the subject matter of the independent claims. Other implementations are apparent from the dependent claims, the description and the drawings.
[0006] According to a beamforming transceiver device, in particular, a device for wireless communication is disclosed. The transceiver device includes a plurality of (N a) a multi-antenna feeder array of active antennas, the active antennas being used to transmit electromagnetic radiation based on a data stream precoded using a beamforming precoder to beamform the electromagnetic radiation. In addition, the beamforming transceiver device includes a plurality of (N p ) of passive antennas, wherein each passive antenna is used to receive at least a portion of the electromagnetic radiation from the multi-antenna feeder array and retransmit the received electromagnetic radiation with a corresponding adjustable phase shift. The transmission from the multiple active antennas of the multi-antenna feeder array to the multiple passive antennas of the RIS is defined as N p ×N a The transmission matrix T is described. The multi-antenna feeder array is used to generate the beamforming precoder to be applied to the data stream based on one or more generalized eigenvectors of the transmission matrix T. Therefore, an improved transceiver device is provided for generating a high-gain narrow beam with very small sidelobes. Compared with conventional devices, the transceiver device is capable of generating a high-gain narrow beam with very small sidelobes and lower power consumption. In addition, since fewer hardware components are required, the transceiver device can be more lightweight and have higher reliability than conventional devices. Since multiple orthogonal eigenmodes including a second eigenmode with very good single-pulse zero depth can be used, the transceiver device can be advantageously used for single-pulse angle tracking. In addition, since the multi-antenna feeder array and the RIS can be software controllable, the transceiver device has higher flexibility.
[0007] In another possible implementation, the multi-antenna feeder array is used to generate the beamforming precoder to be applied to the data stream based on the one or more generalized eigenvectors of the transmission matrix T as a linear combination of the one or more generalized eigenvectors of the transmission matrix T. Therefore, the transceiver device can effectively generate a wide-angle beam, for example, for fan-shaped lighting, beacons, etc.
[0008] In another possible implementation, the multi-antenna feeder array is used to generate the beamforming precoder to be applied to the data stream based on a generalized eigenvector of the transmission matrix T, and the generalized eigenvector has a maximum generalized eigenvalue for maximum power transmission from the multi-antenna feeder array to the RIS.
[0009] In another possible implementation manner, the distance between the RIS and the multi-antenna feeder array is smaller than a Rayleigh distance (also called Rayleigh length) between the RIS and the multi-antenna feeder array.
[0010] In another possible implementation manner, the plurality of passive antennas of the RIS may be arranged on a substantially flat surface or a curved surface.
[0011] In another possible implementation, the multi-antenna feeder array includes a baseband processor configured to precode the data stream using the precoder.
[0012] In another possible implementation, the transmission matrix T has a singular value decomposition (SVD) in the following form:
[0013] ,
[0014] Among them, N a represents the number of active antennas, represents the i-th singular value, represents the i-th left singular vector, represents the Hermitian conjugate of the i-th right singular vector, wherein the one or more generalized eigenvectors are one or more left singular vectors and / or one or more right singular vectors of the SVD of the transfer matrix T. In addition, the singular values can be thought of as the eigenvalues of these generalized eigenvectors.
[0015] In another possible implementation, the RIS is used to control corresponding adjustable phase shifts to retransmit the received electromagnetic radiation, so that the electromagnetic radiation retransmitted by the multiple passive antennas 121 coherently interferes in a desired target direction (ie, beamforming direction), ie, constructively interferes.
[0016] In another possible implementation, the number N of the plurality of passive antennas is p Much larger than the number N of the plurality of active antennas a For example, the number N of the plurality of passive antennas is p The number N of the plurality of active antennas a The ratio can be at least greater than 10.
[0017] According to a second aspect, a method for operating a transceiver device is disclosed, wherein the transceiver device comprises a multi-antenna feeder array having a plurality of active antennas for transmitting electromagnetic radiation based on a data stream precoded using a precoder to beamform the electromagnetic radiation; and a reconfigurable intelligent surface (RIS) having a plurality of passive antennas, wherein each passive antenna is used to receive at least a portion of the electromagnetic radiation from the multi-antenna feeder array and to retransmit the received electromagnetic radiation with a corresponding adjustable phase shift, wherein the transmission from the plurality of active antennas of the multi-antenna feeder array to the plurality of passive antennas of the RIS is defined, i.e. described by a transmission matrix T. The method comprises the steps of generating the precoder to be applied to the data stream based on one or more generalized eigenvectors of the transmission matrix T.
[0018] The method described in the second aspect of the present disclosure can be performed by the transceiver device described in the first aspect of the present disclosure. Therefore, further features of the method described in the second aspect of the present disclosure are directly derived from the functions of the transceiver device described in the first aspect of the present disclosure and the different implementations described above and below.
[0019] According to a third aspect, a computer program product is provided, comprising a program code, and when the program code is executed by a computer or a processor, the program code causes the computer or the processor to perform the method as described in the second aspect.
[0020] The following drawings and description set forth the details of one or more embodiments. Other features, objects, and advantages are apparent in the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The following is a detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings. In the accompanying drawings:
[0022] Figure 1 A schematic diagram of a beamforming transceiver device according to an embodiment is shown, particularly for wireless communications;
[0023] Figure 2a to Figure 2c shows an exemplary beam pattern generated by a transceiver device according to an embodiment;
[0024] Figure 3 shows a table of values illustrating transceiver device performance according to various embodiments;
[0025] Figure 4 A flow chart of a method of operating a transceiver device according to an embodiment is shown.
[0026] In the following, identical reference signs refer to identical or at least functionally equivalent features. DETAILED DESCRIPTION
[0027] In the following description, reference is made to the accompanying drawings that form a part of the present disclosure, which illustrate specific aspects of the embodiments of the present disclosure or specific aspects in which the embodiments of the present disclosure may be used by way of illustration. It should be understood that the embodiments of the present disclosure may be used in other aspects and include structural or logical changes that are not depicted in the accompanying drawings. Therefore, the following specific embodiments should not be understood in a limiting sense, and the scope of the present disclosure is defined by the appended claims.
[0028] For example, it should be understood that the disclosure related to the described method may also apply to the corresponding device or system configured to perform the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units, such as functional units, to perform the described one or more method steps (e.g., one unit performs one or more steps, or multiple units each perform one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units, such as functional units, the corresponding method may include a step to perform the function of one or more units (e.g., one step performs the function of one or more units, or multiple steps each perform the function of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings. In addition, it should be understood that unless otherwise explicitly stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.
[0029] Figure 1 A beamforming transceiver device 100 according to an embodiment is schematically shown. In an embodiment, the transceiver device 100 may be, for example, a base station or access point 100 for performing beamforming wireless communication with a plurality of user equipments or stations.
[0030] The transceiver device 100 includes a multi-antenna feeder array 110 (in Figure 1 The multi-antenna feeder array 110 includes N a An active antenna 111 is used to transmit electromagnetic radiation based on a data stream precoded using a precoder to beamform the electromagnetic radiation. Figure 1In the illustrated embodiment, the transceiver device 100 includes a baseband processor 112 for generating a precoder and driving a driving signal of a plurality of active antennas 111. Each active antenna 111 may include a low noise amplifier (LNA) ( Figure 1 ), for amplifying the driving signal of the active antenna 111. Although the following description of the transceiver device 100 according to the embodiment focuses on the transmission function of the transceiver device 100, it should be understood that the same concepts adopted for the transmission function of the transceiver device 100 can be applied to its reception function.
[0031] In addition, the transceiver device 100 includes a reconfigurable intelligent surface (RIS) 120. The RIS 120 includes N p passive antennas 121, wherein each passive antenna 121 is used to receive at least a portion of the electromagnetic radiation from the multi-antenna feed array 110 and retransmit the received electromagnetic radiation with a corresponding adjustable phase shift. To this end, RIS 120 may include N p The RIS 120 includes a respective phase shifter 121a for each of the plurality of passive antennas 121 and a control unit 122 for adjusting a phase shift applied by each phase shifter 121a to electromagnetic radiation retransmitted by each passive antenna 121. In one embodiment, the control unit 122 of the RIS 120 is configured to control the respective adjustable phase shifts to retransmit the received electromagnetic radiation such that the electromagnetic radiation retransmitted by the plurality of passive antennas 121 of the RIS 120 coherently, i.e., constructively, interferes in a desired beamforming target direction.
[0032] like Figure 1 As shown, the plurality of passive antennas 121 of the RIS 120 may be disposed on a substantially flat surface of the RIS 120. Alternatively, the plurality of passive antennas 121 of the RIS 120 may be disposed on a curved surface of the RIS 120.
[0033] exist Figure 1 In the illustrated embodiment, the passive antenna 121 of the RIS 120 is located within the near field of the active antenna 111 of the multi-antenna feed array 110. In one embodiment, the distance between the RIS 120 and the multi-antenna feed array 110 is less than the Rayleigh distance (also referred to as the Rayleigh length) between the RIS 120 and the multi-antenna feed array 110.
[0034] Mathematically, the transmission from the multiple active antennas 111 of the multi-antenna feeder array 110 to the multiple passive antennas 121 of the RIS 120 is defined as N p ×N aThe transmission matrix T (also called the near-field propagation matrix T) describes the transmission matrix T. The matrix elements of the transmission matrix T are Given by:
[0035] ,
[0036] in, represents the gain of each active antenna 111, represents the gain of each passive antenna 121, represents the distance from the nth active antenna 111 to the mth passive antenna 121, λ represents the carrier wavelength, represents the deviation angle from the nth active antenna 111 to the mth passive antenna 121, represents the arrival angle from the nth active antenna 111 to the mth passive antenna 121.
[0037] For more details on the transmission matrix T and its dependence on the active antenna 111 and the passive antenna 120, see Tiwari and Caire's paper "On the Behavior of the Near-Field Propagation Matrix between two Antenna Arrays, with Applications to RIS-Based Over-the-Air Beamforming", IEEE VTC2022, Spring, Helsinki, Finland, which is fully incorporated herein by reference.
[0038] As will be described in more detail below, the multi-antenna feed array 110 is used to generate a precoder to be applied to the data stream based on one or more generalized eigenvectors of the transmission matrix T. Similarly, for the receiving function of the transceiver device 100, the multi-antenna feed array 110 can be used to implement a combiner based on one or more generalized eigenvectors of the transmission matrix T.
[0039] Since in most cases, the number N of the plurality of passive antennas 121 of the RIS 120 is p Much larger than the number N of multiple active antennas 111 of the multi-antenna feeder array a , so N p ×N a The transfer matrix T is a highly rectangular matrix, i.e., a non-square matrix. It should be understood that although eigenvectors and eigenvalues are defined for square matrices, generalized eigenvectors can be defined for non-square matrices. For example, in one embodiment, one or more generalized eigenvectors can be the product of the transfer matrix and its Hermitian conjugate, i.e. , one or more eigenvectors of , or One or more feature vectors of .
[0040] In another embodiment, the multi-antenna feed array 110 is used to generate a precoder to be applied to the data stream based on a singular value decomposition (SVD) of the transmission matrix T using one or more generalized eigenvectors of the transmission matrix T, that is:
[0041] ,
[0042] Among them, N a represents the number of active antennas 111, represents the i-th singular value, represents the i-th left eigenvector, represents the Hermitian conjugate of the i-th right eigenvector, wherein the generalized eigenvalues are singular values, and the one or more generalized eigenvectors are one or more left eigenvectors and / or one or more left eigenvectors of the SVD of the transmission matrix T. However, it should be understood that the multi-antenna feed array 110 can generate one or more generalized eigenvectors of the transmission matrix T based on other matrix decompositions other than SVD, for example, based on geometric mean decomposition, generalized tridiagonal decomposition, or adjustable channel decomposition of the transmission matrix T to generate a precoder.
[0043] In one embodiment, the multi-antenna feed array 110 is used to generate a precoder to be applied to the data stream based on the generalized eigenvector of the transmission matrix T with the largest generalized eigenvalue, which can be considered as the main eigenmode of the transmission matrix T. In one embodiment, the generalized eigenvector of the transmission matrix T with the largest generalized eigenvalue can be the one with the largest singular value The left or right singular vector of . Figure 2a FIG. 1 shows an exemplary beam pattern generated by the transceiver device 100 using the generalized eigenvector of the transmission matrix T having the largest generalized eigenvalue for different distances between the multi-antenna feed array 110 and the RIS 120 according to an embodiment. Figure 2a It can be seen that the beams denoted by A, B and C correspond to respective distances of 80 half wavelengths, 127 half wavelengths and the Rayleigh distance between the AMAF 111 and the RIS 120.
[0044] In another embodiment, the multi-antenna feed array 110 is used to generate a precoder to be applied to the data stream based on one or more generalized eigenvectors of the transmission matrix T as a linear combination of the one or more generalized eigenvectors of the transmission matrix T. In one embodiment, the one or more generalized eigenvectors may be one or more left singular vectors and / or one or more right singular vectors of the SVD of the transmission matrix T. In other words, in one embodiment, the multi-antenna feed array 110 is used to generate the precoder as a vector of the form :
[0045] ,
[0046] in, represents the coefficient, i.e. the weight of the linear combination, represents the right singular or generalized eigenvector.
[0047] Figure 2b FIG. 4 shows an exemplary wide-angle flat-top beam pattern generated by the transceiver device 100 according to the embodiment based on a linear combination of the main eigenmode and the third eigenmode of the transmission matrix T. Figure 2b In FIG. 1 , A represents the beam shape obtained from a microstrip patch antenna element with a half-power beamwidth of 90 degrees, and B represents the beam shape obtained from a high-directivity antenna element with a half-power beamwidth of 65 degrees.
[0048] In one embodiment, the transceiver device 100 can implement two RF chains using the primary eigenmode and the secondary eigenmode (mutually orthogonal functions) to create a Figure 2c Two mutually orthogonal angular domain radiation patterns are shown (beam A shows the main eigenmode and beam B shows the second eigenmode). The single pulse null depth of beam B exceeds 50 dB, which enables very accurate angular tracking of the target, i.e., the user does not need any hardware reconstruction or any additional RF hardware. This is conducive to the joint communication and sensing of the transceiver device 100 according to the embodiment. It should be understood that this feature is applicable to different AMAF-RIS distances in the near field.
[0049] Figure 3 1 shows a table of values illustrating the performance of the transceiver device 110 according to various embodiments. More specifically, Figure 3 The table in FIG. 1 lists the RIS gain Γ and some further parameters of the transceiver device 100 according to different embodiments based on numerical simulations, and different embodiments have different quantities. The table shows that the optimal AMAF-RIS distance d in the third column increases with the number N of passive antennas 121 in the second column. p It will be appreciated that the AMAF-RIS loss can be almost completely compensated by the larger aperture gain of RIS 120. It can be seen that by selecting different numbers N of passive antennas 121 p , approximately the same total center beam gain can be obtained for different beam selectivities (which can be obtained from Figure 3 4th column of the table shown).
[0050] Figure 4A flow chart of a method 400 of operating the transceiver device 100 according to an embodiment is shown. The method 400 comprises the following steps: generating a precoder to be applied to a data stream based on one or more generalized eigenvectors of the transmission matrix T.
[0051] The transceiver device 100 according to different embodiments may be advantageously used in a variety of different use cases, such as generating directional and steerable high-gain beams for communications, angle tracking, sector illumination for joint communications and sensing, and the like.
[0052] Those skilled in the art should understand that the “blocks” (“units”) in the various figures (methods and devices) represent or describe the functions of the embodiments of the present disclosure (and are not necessarily independent “units” in hardware or software), thereby equally describing the functions or features of the device embodiments and the method embodiments (unit = step).
[0053] In the multiple embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the described device embodiments are only exemplary. For example, the unit division is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not performed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be implemented through some interfaces. The indirect coupling or communication connection between devices or units can be implemented in electronic, mechanical or other forms.
[0054] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one location, or may be distributed over multiple network units. Some or all of the units may be selected based on actual needs to achieve the purpose of the embodiment scheme.
[0055] In addition, the functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
Claims
1. A transceiver device (100), comprising: A multi-antenna feeder array (110) comprising a plurality of active antennas (111), wherein the plurality of active antennas (111) are used to transmit electromagnetic radiation based on a data stream precoded using a precoder; A reconfigurable smart surface (RIS) (120), wherein the RIS (120) comprises a plurality of passive antennas (121), each passive antenna (121) being configured to receive the electromagnetic radiation from the multi-antenna feed array (110) and retransmit the received electromagnetic radiation with a corresponding adjustable phase shift; wherein transmission from the plurality of active antennas (111) of the multi-antenna feeder array (110) to the plurality of passive antennas (121) of the RIS (120) is defined by a transmission matrix; The multi-antenna feed array (110) is used to generate the precoder based on one or more generalized eigenvectors of the transmission matrix.
2. The transceiver device (100) according to claim 1, wherein: The multi-antenna feed array (110) is used to generate the precoder based on the one or more generalized eigenvectors of the transmission matrix as a linear combination of the one or more generalized eigenvectors of the transmission matrix.
3. The transceiver device (100) according to claim 1 or 2, wherein: The multi-antenna feed array (110) is used to generate the precoder based on the generalized eigenvector of the transmission matrix having the largest generalized eigenvalue.
4. The transceiver device (100) according to any one of the preceding claims, wherein: The distance between the RIS (120) and the multi-antenna feeder array (110) is smaller than the Rayleigh distance between the RIS (120) and the multi-antenna feeder array (110).
5. The transceiver device (100) according to any one of the preceding claims, wherein: The plurality of passive antennas (121) of the RIS (120) are arranged on a substantially flat surface or a curved surface.
6. The transceiver device (100) according to any one of the preceding claims, wherein: The multi-antenna feed array (110) comprises a baseband processor (112) for precoding the data stream using the precoder.
7. The transceiver device (100) according to any one of the preceding claims, wherein: The transfer matrix T has a singular value decomposition (SVD): ， Among them, N a represents the number of active antennas (111), represents the i-th singular value, represents the i-th left singular vector, represents the Hermitian conjugate of the i-th right singular vector, wherein the one or more generalized eigenvectors are one or more left singular vectors and / or one or more right singular vectors of the SVD of the transfer matrix T.
8. The transceiver device (100) according to any one of the preceding claims, wherein: The RIS (120) is used to control the corresponding adjustable phase shifts so that the electromagnetic radiation retransmitted by the multiple passive antennas (121) coherently interferes in a desired target direction.
9. The transceiver device (100) according to any one of the preceding claims, wherein: The number of the plurality of passive antennas (121) is much greater than the number of the plurality of active antennas (111).
10. A method (400) for operating a transceiver device (100), wherein: The transceiver device (100) comprises a multi-antenna feeder array (110) having a plurality of active antennas (111), wherein the plurality of active antennas (111) are used to transmit electromagnetic radiation based on a data stream precoded using a precoder; and a reconfigurable smart surface (RIS) (120) having a plurality of passive antennas (121), wherein each passive antenna (121) is used to receive the electromagnetic radiation from the multi-antenna feeder array (110) and retransmit the received electromagnetic radiation with a corresponding adjustable phase shift, wherein the transmission from the plurality of active antennas (111) of the multi-antenna feeder array (110) to the plurality of passive antennas (121) of the RIS (120) is defined by a transmission matrix, and the method (400) comprises the following steps: The precoder is generated based on one or more generalized eigenvectors of the transmission matrix.
11. A computer program product comprising a computer-readable storage medium, wherein: The computer-readable storage medium is used to store program codes, and when the program codes are executed by a computer or a processor, the computer or the processor executes the method (400) of claim 10.