Method for constructing large-capacity hybrid multi-beam array based on passive beamforming network

Abstract

This invention discloses a method for constructing a high-capacity hybrid multi-beam array based on a passive beamforming network, belonging to the field of radio frequency system technology. This method divides the space into two dimensions, employing different beamforming techniques to achieve hybrid domain beamforming, thus reducing system complexity while ensuring high performance. Specifically: In the first dimension, the space is divided into multiple sub-regions using a passive beamforming network of active submodules. A combiner connects the same channels from different active submodules within the same submodule group to a single ADC / DAC, improving single-beam gain without increasing system complexity. In the second dimension, a digital baseband processing module aggregates and processes the data streams from the same numbered digital channels in different active submodule groups, reducing computational load and ensuring full-aperture gain. This invention can be applied to scenarios such as 5G / 6G millimeter-wave communication and radar imaging, reducing system complexity and power consumption while supporting high-capacity data streams.

Description

Technical Field

[0001] This invention relates to the field of radio frequency systems, and in particular to a method for constructing a large-capacity hybrid multi-beam array based on a passive beamforming network, applicable to scenarios such as 5G / 6G / satellite communication millimeter-wave massive MIMO arrays and radar imaging. Background Technology

[0002] Driven by various practical and potential applications, large-scale active beamforming array technology has received significant attention in recent years, such as 5G / 6G millimeter-wave communication and high-throughput satellite communication. Methods for implementing large-scale beamforming arrays can be broadly categorized into three types: analog beamforming, digital beamforming, and hybrid beamforming. Traditional large-scale active analog beamforming arrays have only one tunable beam capable of achieving full-aperture gain at any given time. Increasing the number of tunable beams requires a multiple increase in the number of RF channels, leading to a rapid rise in system complexity and cost. All-digital beamforming systems (including symmetric and asymmetric architectures) can support tens to hundreds of concurrent data streams, achieving an order-of-magnitude leap in system capacity. From a performance perspective, the symmetric all-digital beamforming array architecture performs best among various beamforming array solutions; however, this architecture has significant bottlenecks: the large-scale deployment of high-speed analog-to-digital converters (ADCs) and the need for real-time processing of massive amounts of data result in high system costs, power consumption, and complexity. Simultaneously, the massive computational tasks place extremely high demands on hardware computing resources. Therefore, current 5G millimeter-wave base stations mainly adopt a hybrid beamforming large-scale MIMO array architecture that combines radio frequency phase-shifting phased arrays (active analog beamforming subarrays) with digital domain beamforming. Each two-dimensional radio frequency subarray is connected to one up-converter, and then beamforming is performed again in the digital domain. However, this hybrid multi-beam architecture cannot achieve independent phase control on all paths from each data stream to each antenna element. Therefore, either each data stream's corresponding beam uses only one phased array to achieve independent beam control (but at the cost of full-aperture gain), or each beam uses full-aperture gain (all beams are bundled together, losing independent control capability). Based on this, it is necessary to develop a new type of large-scale hybrid beamforming array, with the goal of improving the current traditional hybrid beamforming array, effectively reducing the system's power consumption, complexity, and computational load, while increasing system capacity. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a hybrid multi-beam array construction method based on passive beamforming networks, which can improve the system capacity of the array system while effectively reducing the power consumption, complexity and computational load of the array system.

[0004] Technical solution: To achieve this objective, the present invention adopts the following technical solution:

[0005] A method for constructing a high-capacity hybrid multi-beam array based on a passive beamforming network includes the following steps:

[0006] Step S1: Construct P identical active subarray modules in the first dimension. Each active subarray module includes an array surface composed of n radiating elements, an m×n passive beamforming network, and a multi-channel radio frequency module containing m transceiver channels. The transceiver channels in each multi-channel radio frequency module are numbered 1 to m in the same way.

[0007] Step S2: The signals corresponding to the same numbered transceiver channels in the P active subarray modules are combined into one channel by the combiner module to obtain m combined signals. The m combined signals are then connected to m different analog-to-digital converters or digital-to-analog converters. Each analog-to-digital converter or digital-to-analog converter corresponds to an independently adjustable beam, and each beam can control all P×n radiating elements. By independently adjusting the amplitude and phase of all transceiver channels connected to the analog-to-digital converter or digital-to-analog converter, the pointing of each beam in the first dimension can be independently adjusted.

[0008] Step S3: Construct k identical active subarray module groups in the second dimension, each active subarray module group consisting of P identical active subarray modules;

[0009] Step S4: The baseband processing module includes m×k ports connected to the analog-to-digital converter or digital-to-analog converter respectively, and m×k beamport clusters; each beamport cluster is formed by converging digital channel data streams with the same number in all different active subarray module groups, and specific beam pointing is achieved by performing amplitude and phase weighting on each data stream in the baseband.

[0010] Furthermore, in the method for constructing a high-capacity hybrid multi-beam array based on a passive beamforming network:

[0011] The passive beamforming network is a fully connected network, meaning that there is a connection path between any input port and each output port. The excitation of each input port can obtain different output amplitude and phase combinations at each output port, corresponding to beams pointing in different directions.

[0012] The passive beamforming network is implemented using any one of the following: Butler matrix, Blass matrix, Nolan matrix, multimode cavity beamforming network, Rotman lens, or R-kR lens;

[0013] The number of input ports m and the number of output ports n of the passive beamforming network satisfy m≤n.

[0014] Furthermore, the center-to-center spacing of adjacent radiating elements in the active subarray module is controlled within half an air wavelength, and the active subarray module satisfies the following when expanded in two dimensions:

[0015] In the first dimensional expansion direction, the spacing between the edge radiation elements of adjacent submodules is the same as the spacing between elements within the submodule and is no greater than half the center wavelength;

[0016] In the second dimensional expansion direction, the distance between the edge radiation units of adjacent submodule groups is also no greater than half a center wavelength.

[0017] Furthermore, the multi-channel RF module also includes an up-conversion module or a down-conversion module; for the multi-channel RF module that includes a frequency conversion module, the intermediate frequency signal is aggregated through the combiner module; for the multi-channel RF module that does not include a frequency conversion module, the RF signal is aggregated through the combiner module.

[0018] Furthermore, the digital baseband processing module adopts a centralized baseband processing platform or a distributed baseband processing platform to perform calculations on all data channels involved in each beamport cluster, thereby realizing hierarchical beamforming and localizing the beamforming matrix of the all-digital multi-beam array from a full array to a block diagonal array.

[0019] The present invention also provides a high-capacity hybrid multi-beam array system based on a passive beamforming network, comprising:

[0020] P active subarray modules, each of the active subarray modules including an array surface composed of n radiating elements, an m×n passive beamforming network, and a multi-channel radio frequency module containing m transceiver channels;

[0021] There are k active subarray module groups, and each active subarray module group consists of P active subarray modules;

[0022] The combiner module consists of m combiners. Each combiner connects to the same numbered transceiver channels in all the active subarray modules and connects the combined m signals to m different analog-to-digital converters or digital-to-analog converters. The signal output by each analog-to-digital converter or digital-to-analog converter corresponds to a beam that can be independently controlled in the first dimension.

[0023] The digital baseband processing module is used to aggregate the digital channel data streams with the same number from all different active subarray module groups, and to realize m×k beams that can be independently controlled in the second dimension through amplitude and phase weighting.

[0024] The dynamic power management unit is used to shut down the RF channels and analog-to-digital converters or digital-to-analog converters in idle sub-regions.

[0025] Preferably, the passive beamforming network uses a Butler matrix, where the number of input ports m is less than or equal to the number of output ports n.

[0026] Preferably, the digital baseband processing module supports hierarchical processing and adopts a centralized computing architecture or a distributed computing architecture.

[0027] Preferably, the system is used in 5G / 6G millimeter-wave base stations, high-throughput satellite communication equipment, or radar imaging equipment to achieve multi-beam concurrency and full-aperture gain.

[0028] Beneficial effects: This invention discloses a method for constructing a high-capacity hybrid multi-beam array based on a passive beamforming network. By dividing the array into multiple active sub-modules in one dimension (each sub-module includes a radiating element array, a passive beamforming network, and a multi-channel RF module), and using a combiner network to combine the RF channels with the same number in each sub-module, and then connecting them to a digital-to-analog / analog-to-digital converter to synthesize independent beams, each beam can obtain full-aperture gain in one dimension.

[0029] In addition, in each submodule group, a combiner network is used to combine the radio frequency channels with the same number in each submodule, and then connect them to a digital-to-analog / analog-to-digital converter. This improves beam performance without increasing the cost and complexity of the system.

[0030] Meanwhile, a digital beamforming method is adopted in another dimension, and the beamforming matrix of the all-digital multi-beam array is localized from a full array to a block diagonal array. Compared with the all-digital multi-beam array system, the complexity and computational load of this system are significantly reduced.

[0031] Preferably, compared with traditional hybrid multi-beam array systems based on radio frequency phase-shifting phased subarrays, the large-scale hybrid beamforming array constructed by this invention greatly increases the number of beams or data streams in the system. With one antenna element connected to the output port of each passive beamforming matrix, the number of beams or data streams supported by the system is equal to the number of array antenna elements.

[0032] Preferably, each subarray can be calibrated by adjusting the amplitude and phase of each transmit / receive channel in the multi-channel RF module.

[0033] Preferably, by adjusting the phase of each transmit / receive channel in the multi-channel RF module, sub-region scanning can be achieved, making the sub-region coverage no longer fixed, thereby further expanding the scanning range of the array's high-gain beam. Preferably, for multiple sets of equipment, controlling the scanning of sub-regions can merge and focus the beams of multiple sets of equipment, improving the overall EIRP performance of the beam.

[0034] Preferably, power consumption can be dynamically managed by shutting down the radio frequency channels of idle sub-regions through software control. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the array architecture in a specific embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram showing the breakdown of the tile-type active array submodule in a specific embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of a large-scale beamforming array constructed by expanding active sub-modules in one dimension, as described in a specific embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of a large-scale beamforming array constructed by extending active sub-modules in two orthogonal dimensions in a specific embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the spatial beam distribution effect in a specific embodiment of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0041] Example 1

[0042] This embodiment discloses a method for constructing a high-capacity hybrid beamforming array based on a passive beamforming network, the specific steps of which include:

[0043] 1. Construction of active subarray modules (corresponding to...) Figure 1 , Figure 2 )

[0044] In step S1, P identical active subarray modules (AM1~AMP) are constructed in the first dimension (which can be a vertical or horizontal dimension). Each active subarray module includes:

[0045] Array plane 101: Composed of n radiating elements 1011, with element spacing d1 ≤ 0.5. , The center wavelength is .

[0046] Passive beamforming network 201: AM1 to AMP all adopt an m×n Butler matrix, with its n output ports connected to the radiating element 1011 and its m input ports connected to the CH1 to CHm channels of the multi-channel RF module 301. Figure 1 In this context, "CHm" represents the radio frequency channel number.

[0047] Multi-channel RF module 301:

[0048] Each submodule contains m transmit / receive channels (CH1~CHm), and each channel includes amplitude and phase control modules. All submodules have the same configuration:

[0049] Option A: All sub-modules integrate up / down frequency converter modules, the combiner outputs intermediate frequency signals, which are then converted to radio frequency signals by a common frequency converter;

[0050] Option B: All sub-modules have no frequency converter module, and the combiner directly outputs the radio frequency signal;

[0051] An analog-to-digital converter / digital-to-analog converter (ADC / DAC) module 501.

[0052] 2. Active subarray module extension and analog domain independent beam synthesis and control (corresponding to) Figure 1 , Figure 3 )

[0053] In step S2, when expanding P identical active subarray modules in the first dimension (which can be a vertical or horizontal dimension), the spacing d between the edge radiating elements of adjacent subarray modules in the expansion direction is... e The spacing d1 is the same as the unit spacing d1 within the submodule, and d e ≤0.5 , With the center wavelength as the center wavelength, the total radiating element after expansion is P. n.

[0054] Beamforming is performed in the vertical dimension using combiner module 401. Specifically, this involves combining the signals corresponding to the same numbered transmit / receive channels in the expanded active subarray module into a single signal, which is then connected to m different ADC / DAC modules. Each ADC / DAC 501 corresponds to an independently adjustable output beam in the vertical dimension.

[0055] 1) Beamforming:

[0056] The ADC / DAC module 5011 controls the CH1 channel signal of AM1~AMP and outputs beam B1;

[0057] The ADC / DAC module 5012 controls the CH2 channel signals of AM1~AMP and outputs beam B2;

[0058] ...

[0059] The ADC / DAC module 501m controls the CHm channel signals of AM1~AMP and outputs beam Bm;

[0060] 2) Beam control:

[0061] The amplitude and phase of all CHm channels connected to each ADC / DAC module can be independently adjusted so that the corresponding beam Bm can be pointed to the target sub-region;

[0062] Since the combiner modules are connected to different passive beamforming networks, each beam can mobilize the full array units to work together to achieve full-aperture gain in the extension direction.

[0063] 3. Construction of active subarray module groups (corresponding to) Figure 1 , Figure 4 )

[0064] In step S3, k identical active subarray module groups (ADG1~ADGk) are constructed in the second dimension (horizontal dimension), and each active subarray module group consists of P identical active subarray modules (AM1~AMP);

[0065] 4. Digital domain independent beam synthesis and control (corresponding to) Figure 1 , Figure 4 )

[0066] The digital baseband processing module aggregates the digital channel data streams with the same number in each active subarray module group, forming a total of m. A cluster of k beam ports can support output m k independently adjustable beams:

[0067] The digital baseband processing module A1 controls the signals of the ADC / DAC-1 in the active subarray group AMG1~AMGk and outputs beams. By performing different amplitude and phase weights on each data stream in the baseband, different output beams (A11~A1k) can be formed at the output port, each corresponding to a different target sub-region.

[0068] The digital baseband processing module A2 controls the signals of the ADC / DAC-2 in the active subarray groups AMG1~AMGk and outputs beams. By performing different amplitude and phase weights on each data stream in the baseband, different output beams (A21~A2k) can be formed at the output port, each corresponding to a different target sub-region.

[0069] ...

[0070] The digital baseband processing module Am controls the signals of the ADC / DAC-2 in the active subarray group AMG1~AMGk and outputs beams. By performing different amplitude and phase weights on each data stream in the baseband, different output beams (Am1~Amk) can be formed at the output port, each corresponding to a different target sub-region.

[0071] Example 2

[0072] This embodiment provides a high-capacity hybrid beamforming array system based on a passive beamforming network.

[0073] 1. System hardware architecture (corresponding) Figure 1 )

[0074] The system includes:

[0075] P = 4 active subarray modules (AM1~AM4), each submodule contains:

[0076] Array surface 101: Composed of n=4 radiating elements with an element spacing D1=5mm (suitable for the 28 GHz millimeter wave band);

[0077] Passive beamforming network 201: AM1 to AP4 all adopt 4×4 Butler matrix, where n=4 output ports are connected to radiating element 1011, and m=4 input ports are connected to CH1 to CH4 channels of multi-channel RF module 301;

[0078] Multi-channel RF module 301: Contains 4 transceiver channels, each of which includes amplitude and phase control modules as well as up and down conversion modules.

[0079] K = 16 active subarray module groups, each subarray group contains P = 4 active subarray modules, where the combiner network 401 and the ADC / DAC module 501 form four independent adjustable beams in the vertical dimension.

[0080] Digital baseband processing module 601: supports 64 beamport clusters (A11~A64), and digital beamforming of the corresponding sub-region for each beam processing.

[0081] Dynamic power management unit: shuts down the RF channels of idle sub-regions via software control.

[0082] 2. Beam control and application scenarios

[0083] A 5G base station (28 GHz band) uses baseband to apply different amplitude and phase weights to each data stream and adjusts the amplitude and phase of 64 transceiver channels. This allows 64 beams to be directed at different users, and each beam can obtain full-aperture gain.

[0084] As can be seen from the above embodiments, this invention utilizes a spatial two-dimensional hybrid beamforming architecture, employing a passive beamforming network and a combiner module to achieve full-aperture gain. Furthermore, in the vertical dimension, the combiner module combines different active subarray modules within the same active subarray module group, connecting them to only one ADC / DAC module. This significantly reduces system complexity while improving beam gain. Additionally, power consumption can be reduced by dynamically shutting down idle CH channels, making it suitable for 5G / 6G and radar scenarios.

[0085] Example 3

[0086] This embodiment provides a specific communication or radar device that integrates the aforementioned high-capacity hybrid beamforming array system.

[0087] Application scenarios: Urban hotspots, indoor coverage, and other scenarios requiring high-capacity millimeter-wave communication.

[0088] Hardware configuration: The system described in Example 2 is used;

[0089] Dynamic control: Dynamically activate the beams in sub-regions based on the user density within the region.

[0090] Any aspects of this invention not described in detail are well-known to those skilled in the art.

[0091] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples, without contradiction. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this invention through logical analysis, reasoning, or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for constructing a high-capacity hybrid multi-beam array based on a passive beamforming network, characterized in that, Includes the following steps: Step S1: Construct P identical active subarray modules (AM1~AMP) in the first dimension. Each active subarray module includes an array surface (101) composed of n radiating elements (1011), an m×n passive beamforming network (201), and a multi-channel radio frequency module (301) containing m transceiver channels. The transceiver channels in each multi-channel radio frequency module (301) are numbered 1~m in the same way. Step S2: Based on the P active subarray modules (AM1~AMP) constructed in step S1, the signals corresponding to the same numbered transmit and receive channels in the P active subarray modules are combined into one channel through the combiner module (401) to obtain m combined signals. The m combined signals are then connected to m different analog-to-digital converters or digital-to-analog converters (501) respectively, so that each analog-to-digital converter or digital-to-analog converter (501) corresponds to an independently adjustable beam, and each beam can control all P×n radiating elements (1011), realizing an independently adjustable beam with full aperture gain in the first dimension; Step S3: Construct k identical active subarray module groups (AMG1~AMGk) in the second dimension, each active subarray module group consisting of P identical active subarray modules (AM1~AMP); Step S4: Based on the k active subarray module groups (AMG1~AMGk) constructed in step S3, the baseband processing module (601) aggregates the digital channel data streams with the same number in all different active subarray module groups to form m×k beamport clusters. Each beamport cluster corresponds to an independently adjustable beam. By performing amplitude and phase weighting on each data stream in the baseband, independent control of beam pointing is achieved in the second dimension.

2. The construction method according to claim 1, characterized in that, The passive beamforming network (201) is a fully connected network, meaning that there is a connection path between any input port and every output port. It is implemented using any one of the following: Butler matrix, Blass matrix, Nolan matrix, multimode cavity beamforming network, Rotman lens, or R-kR lens.

3. The construction method according to claim 1, characterized in that, The number of input ports m of the passive beamforming network (201) is less than or equal to the number of output ports n; the center-to-center spacing of adjacent radiating elements (1011) in the active subarray module (AM1~AMP) is controlled within half an air wavelength.

4. The construction method according to claim 1, characterized in that, When the active subarray modules (AM1~AMP) are expanded in two dimensions, the following conditions must be met: in the first dimension of expansion, the spacing between the edge radiating elements of adjacent submodules is the same as the spacing between the elements within the submodule and is not greater than half a center wavelength; in the second dimension of expansion, the spacing between the edge radiating elements of adjacent submodule groups is also not greater than half a center wavelength.

5. The construction method according to claim 1, characterized in that, The multi-channel radio frequency module (301) also includes an up-conversion module or a down-conversion module; for the multi-channel radio frequency module (301) that includes a frequency conversion module, the intermediate frequency signal is gathered through the combiner module (401); for the multi-channel radio frequency module (301) that does not include a frequency conversion module, the radio frequency signal is gathered through the combiner module (401).

6. The construction method according to claim 1, characterized in that, The baseband processing module (601) adopts a centralized baseband processing platform or a distributed baseband processing platform to perform calculations on all data channels involved in each beamport cluster to achieve hierarchical beamforming and localize the beamforming matrix of the all-digital multi-beam array from a full array to a block diagonal array.

7. The construction method according to claim 1, characterized in that, It also includes the ability to dynamically manage power consumption by shutting down the RF channels and analog-to-digital converters or digital-to-analog converters (501) in idle sub-regions through a dynamic power management unit.

8. A high-capacity hybrid multi-beam array system based on a passive beamforming network, constructed using the method described in any one of claims 1-7, characterized in that, include: P active subarray modules (AM1~AMP), each active subarray module includes an array surface (101) composed of n radiating elements (1011), an m×n passive beamforming network (201), and a multi-channel radio frequency module (301) containing m transceiver channels. There are k active subarray module groups (AMG1~AMGk), and each active subarray module group consists of P active subarray modules (AM1~AMP); The combiner module (401) consists of m combiners. Each combiner connects to the same numbered transceiver channels in all the active subarray modules (AM1~AMP). The combined m signals are connected to m different analog-to-digital converters or digital-to-analog converters (501). The signal output by each analog-to-digital converter or digital-to-analog converter (501) corresponds to a beam that can be independently controlled in the first dimension. The baseband processing module (601) is used to aggregate the digital channel data streams with the same number in all different active subarray module groups (AMG1~AMGk), and realize m×k beams that can be independently controlled in the second dimension through amplitude and phase weighting; Dynamic power management unit for shutting down the RF channel and analog-to-digital converter or digital-to-analog converter (501) of idle sub-regions.

9. The system according to claim 8, characterized in that, The passive beamforming network (201) adopts a Butler matrix, and its number of input ports m is less than or equal to the number of output ports n; the baseband processing module (601) adopts a centralized computing architecture or a distributed computing architecture, and supports hierarchical beamforming processing.

10. A communication device, characterized in that, The system includes the high-capacity hybrid beamforming array system as described in claim 8 or 9, for use in 5G / 6G millimeter-wave communication, satellite communication, or radar imaging scenarios.

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