Device and method for assisting millimeter wave communication through low-frequency direction finding

Abstract

The invention discloses a low-frequency direction-finding auxiliary millimeter wave communication device and method. The device comprises a signal generation module, a control module, a data link module, a software processing module, a millimeter wave array and a sensing array. The signal generation module is connected with the sensing array and sends out a generated sensing signal through the sensing array; the control module is connected with the millimeter wave array and controls the beam direction of the millimeter wave array by controlling the configuration information; the data link module is used for receiving sensing data and transmitting millimeter wave array angle control information; and the software processing module is used for calculating angle sensing data and generating corresponding millimeter wave array control information. A sensing signal received by the sensing array is connected to the software processing module through the data link module to calculate a corresponding sensing angle, and the sensing angle is transmitted to the millimeter wave array through the control module. According to the invention, the angle detection overhead of millimeter wave communication is effectively reduced, the communication efficiency is improved, and the engineering practicability is high.

Description

Technical Field

[0001] The present invention belongs to the field of mobile communications, and particularly relates to a device and method for low-frequency direction finding to assist millimeter-wave communication. Background Art

[0002] In a millimeter-wave communication system, beamforming technology is implemented through large-scale MIMO (Multiple Input Multiple Output). This technology performs weighted processing on signals to form a beamforming gain in the desired signal direction, thereby increasing the signal strength in the desired direction and compensating for severe path loss. To ensure a high beamforming gain, the beam directions used by the transceiver must cover the main path of the millimeter-wave channel, which requires searching the entire beam space to find the best transceiver beam pair. In addition, a large-scale antenna array forms highly directive beams. In a dynamic millimeter-wave communication scenario, when the transceiver moves or the wireless channel environment changes, a serious beam misalignment phenomenon will occur, resulting in the beam being unable to align with the communication user, seriously affecting the system communication rate.

[0003] Currently, for beam alignment in a millimeter-wave communication system, beam search technology is usually introduced. Common beam search algorithms are mainly divided into two categories. The first category uses narrow beams with high resolution for exhaustive search, and then finds the best beam combination based on the maximum power principle. The second category uses beams with different resolutions for hierarchical search. The hierarchical search first finds the best beam through the low-resolution beams in the upper layer, and then uses high-resolution beams to search the coverage range of the best beam in the upper layer during the lower-layer search.

[0004] Although traditional beam search methods are relatively easy to implement from a practical perspective, these two types of methods have several major drawbacks. For narrow-beam exhaustive search, first, when using narrow beams with high resolution for exhaustive search, the system needs to evaluate a large number of beam combinations. This not only consumes a large amount of computing resources but also significantly increases the search time, especially in the case of frequent user movement or environmental changes. Second, due to the need for comprehensive search, real-time performance is affected, and it may not be able to meet the rapid response requirements of communication services in dynamic scenarios. For hierarchical search, this method depends on the best beam found by the low-resolution beams. If the search result in the upper layer is inaccurate, it will directly affect the high-resolution search in the lower layer, resulting in a decrease in the reliability of the final result. Summary of the Invention

[0005] Object of the Invention: In view of the deficiencies in the prior art, the present invention designs a device and method for low-frequency direction finding to assist millimeter-wave communication. By using another set of low-frequency angle sensing arrays fixedly connected to the millimeter-wave phased array, the angle estimation at the transceiver end is independently performed, thereby reducing the angle detection overhead of the communication device and improving the communication efficiency.

[0006] Technical solution: To achieve the above-mentioned invention purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a device for low-frequency direction finding-assisted millimeter-wave communication, including a signal generation module, a control module, a data link module, a software processing module, a millimeter-wave array, and a sensing array;

[0008] The millimeter-wave array is used for air interface transceiver of communication signals;

[0009] The sensing array is used for air interface transceiver of angle sensing signals;

[0010] The signal generation module is connected to the sensing array and sends the generated sensing signals through the sensing array;

[0011] The control module is connected to the millimeter-wave array and controls the beam direction of the millimeter-wave array through control configuration information;

[0012] The data link module is used for receiving sensing data and transmitting angle control information of the millimeter-wave array;

[0013] The software processing module is used for calculating angle sensing data and generating corresponding millimeter-wave array control information;

[0014] The sensing signals received by the sensing array are connected to the software processing module via the data link module, and the corresponding sensing angles are calculated through the software processing module. The sensed angles are then transmitted to the millimeter-wave array through the control module.

[0015] Further, the sensing array and the millimeter-wave array are fixedly connected together. Based on the sensing signals of the sensing array, real-time angle estimation is performed, and the corresponding angle configuration information is filled in the header part through a predefined data packet structure, thereby completing the beam configuration of the millimeter-wave array and realizing real-time control of the beam direction of the millimeter-wave array.

[0016] Further, the low-frequency Multiple Signal Classification (MUSIC) algorithm is used in the software processing module for direction finding. First, an estimated value of the covariance matrix is obtained according to the received signal vector, and then the covariance matrix is subjected to singular value decomposition to obtain the eigenvalues and eigenvectors of the spatial covariance matrix; the signal subspace and the noise subspace are obtained according to the order of the eigenvalues, and finally the estimated value of the direction of arrival is obtained by seeking the peak value.

[0017] Further, the data packet structure of the millimeter-wave array control information generated in the software processing module is as follows: the first line of the data packet includes a timestamp, a channel index, the count value of the data packet, the length of the data segment, and the identification of the data packet; the remaining packet header lines represent the phased array configuration information of each user, including the configuration time, the beam pointing direction of the corresponding user, the gain magnitude, the current transceiver state, the configuration word identification of the millimeter-wave array, and the control word valid bit.

[0018] Further, the software processing module is further configured to parse communication data, calculate its corresponding signal-to-noise ratio, and perform stability discrimination on the signal-to-noise ratio, so as to generate a quantization criterion for the beam alignment effect.

[0019] Further, the control module includes a control word configuration receiving sub-module, a control word transmission timing control sub-module, and a control word transmission sub-module;

[0020] The control word configuration receiving sub-module is configured to receive a beam direction control word from the software processing module and parse the beam direction configuration time;

[0021] The control word transmission timing control sub-module is configured to compare the configuration time parsed by the control word configuration receiving sub-module, denoted as ve, with the vitatime value on the board, denoted as va. When ve > va, continue to wait; when ve ≤ va, start the control word transmission sub-module;

[0022] The control word transmission sub-module is configured to generate a control signal according to the transmission protocol CusSPI and output the control word.

[0023] Further, the CusSPI communicates with the millimeter-wave array in the form of a bus, including a data signal PSA_DATA, a clock signal PSA_DCLK, a data transmission enable signal PSA_FCLK, and a data latch signal PSA_LE; when the PSA_FCLK signal is at a low level, it indicates the start of data transmission. At the same time, the PSA_DATA data is valid at the rising edge of PSA_DCLK. When the frame data transmission is completed, the PSA_FCLK signal returns to a high level. After a delay period, the PSA_LE signal issues a positive pulse, indicating that the frame data transmission is completed and starts to configure the millimeter-wave array according to the control word.

[0024] In a second aspect, the present invention provides a method for low-frequency direction finding-assisted millimeter-wave communication, including the following steps:

[0025] The sensing signal generated by the signal generation module is sent out through the sensing array.

[0026] After the sensing array receives the sensing signal, the software processing module calculates the corresponding sensing angle, generates the corresponding millimeter-wave array control information, and transmits it to the millimeter-wave array through the control module;

[0027] After the control module receives the control information obtained according to the sensing angle, it controls the beam direction of the millimeter-wave array through the control configuration information.

[0028] Further, the data packet structure transmitted between the software processing module and the control module is as follows: The first line of the data packet includes the timestamp, channel index, count value of the data packet, length of the data segment, and identification of the data packet; The remaining header lines represent the phased array configuration information of each user, including the configuration time, beam pointing direction of the corresponding user, gain size, current transceiver state, configuration word identification of the millimeter-wave array, and control word valid bit.

[0029] Further, the steps for the control module to configure the millimeter-wave array include:

[0030] Receive the beam direction control word from the software processing module and parse the beam direction configuration time;

[0031] Compare the configuration time parsed by the control word configuration receiving sub-module, denoted as ve, with the vitatime value on the board, denoted as va. When ve > va, continue to wait; when ve ≤ va, generate a control signal according to the transmission protocol CusSPI and output the control word.

[0032] Advantageous effects. Compared with the prior art, the present invention has the following advantages:

[0033] 1) The present invention uses a dual-frequency and dual-array radio frequency architecture. The low-frequency angle sensing array with a fixed connection independently performs angle estimation, reducing the need for complex beam training and search, thereby reducing the angle search overhead on the communication side of the system and improving communication efficiency.

[0034] 2) The present invention can achieve accurate angle estimation by adopting a low-frequency angle estimation algorithm, such as a high-frequency millimeter-wave mobile communication system assisted by the multiple signal classification algorithm, thereby optimizing the beamforming result and signal transmission quality.

[0035] 3) The implementation of the present invention can use a multi-element heterogeneous computing architecture, giving full play to the respective advantages of the CPU and FPGA heterogeneous chip organizations, and achieving optimal allocation and efficient utilization of computing resources. This architecture design enables the system to dynamically adjust resources according to the characteristics of tasks when processing different types of tasks, thereby achieving higher performance and lower energy consumption. Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the device array structure in the embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the software and hardware architecture of the device in the embodiment of the present invention.

[0038] Figure 3 It is a schematic diagram of the implementation process of angle estimation in the embodiment of the present invention.

[0039] Figure 4 It is a schematic diagram of the data packet of the transmission control word in the embodiment of the present invention.

[0040] Figure 5 It is an interaction logic diagram between the low-frequency direction-finding array and the millimeter-wave phased array in the embodiment of the present invention.

[0041] Figure 6 It is a schematic diagram of the control word transmission protocol of the control module in the embodiment of the present invention. Detailed implementation manners

[0042] The following further describes the present invention in conjunction with the accompanying drawings and specific embodiments. These embodiments are only used to illustrate the present invention and do not limit the protection scope of the present invention.

[0043] A device for low-frequency direction-finding assisted millimeter-wave communication disclosed in an embodiment of the present invention includes a signal generation module, a control module, a data link module, a software processing module, a millimeter-wave array, and a sensing array. The millimeter-wave array is used for the air interface transceiver of communication signals, and the sensing array is used for the air interface transceiver of angle sensing signals. The signal generation module is connected to the sensing array and sends the generated sensing signals (cyclically sending known signals as reference signals through the on-board unit) through the sensing array. The control module is connected to the millimeter-wave array and controls the beam direction of the millimeter-wave array through control configuration information. The control module converts the control information to be transmitted into binary codes, loads them on the millimeter-wave array, and then controls the receive / transmit state of the millimeter-wave array and the corresponding beam direction. The data link module is used for receiving sensing data and transmitting the angle control information of the millimeter-wave array; the software processing module is used for calculating the angle sensing data and generating the corresponding millimeter-wave array control information. The sensing signals received by the sensing array are connected to the software processing module via the data link module and the corresponding sensing angles are calculated through the software processing module. The sensed angles are then transmitted to the millimeter-wave array through the control module.

[0044] Figure 1It shows the basic architecture of the device in this embodiment. The core of the device is the communication service of the millimeter-wave phased array. The perception assistance mainly uses the data obtained by another set of perception arrays to perform real-time angle estimation through algorithms, and then configures the estimated angle into the millimeter-wave phased array to ensure the real-time alignment of the beam, thereby ensuring stable data transmission. In a specific embodiment, the perception array and the millimeter-wave array are fixedly connected together. Based on the perception signal of the perception array, real-time angle estimation is performed, and the corresponding angle configuration information is filled in the header part through a pre-agreed data packet structure, and then the beam configuration of the millimeter-wave array is completed, realizing the real-time control of the beam direction of the millimeter-wave array.

[0045] Figure 2 It shows the basic architecture involved in the device of this embodiment. There are mainly three parts involved in this device. First is the RF front-end part on the far right. This part mainly realizes the conversion of RF signals to analog intermediate-frequency signals. Among them, the high-frequency millimeter-wave phased array is responsible for the air interface transceiver of communication signals and completes communication-related services; the low-frequency perception array is responsible for the air interface transceiver of angle perception signals and completes angle perception-related services.

[0046] The data link module mainly realizes the intermediate forwarding and transparent transmission of the collected data to the software processing module. This part includes the FPGA (Field-Programmable Gate Array) board of the RFSoC (RF System on Chip) on-board RF chip and the data acceleration card. The analog signal transmitted from the RF front-end is directly collected and converted into a digital signal through the intermediate-frequency ADC (Analog-to-Digital Converter). Then the collected data will be transmitted to the data card through the optical port, and then transmitted from the data card to the server through PCIe (Peripheral Component Interconnect Express). At the same time, the on-board DAC (Digital-to-Analog Converter) continuously sends known signals as reference signals. In this embodiment, the data link module is implemented using a Zynq UltraScale+RFSoC board and a U50 data acceleration card. The analog signal transmitted from the RF front-end is directly collected and converted into a digital signal through the intermediate frequency, and then the collected data will be transmitted to the data card through the Aurora optical port, and then transmitted from the data card to the X86 server through PCIe.

[0047] The software processing module mainly includes a communication data processing sub-module and an angle perception data processing sub-module. After the server receives the data packets transmitted from the PCIe, it respectively parses the communication data and the angle perception data in the data packets. For the communication data, the corresponding signal-to-noise ratio is calculated, and the stability of the signal-to-noise ratio is judged, so as to generate a quantization criterion for the beam alignment effect. For the angle perception data, first, channel calibration is performed, and then the MUSIC algorithm is used to calculate the corresponding angle perception result. Then, through peripheral control, the real-time control of the beam direction of the millimeter-wave phased array is realized by using the custom CusSPI (Custom Serial Peripheral Interface).

[0048] In the angle perception data processing sub-module, the MUSIC algorithm is used for direction finding. First, the estimated value of the covariance matrix is obtained according to the received signal vector, and then the covariance matrix is subjected to singular value decomposition to obtain the eigenvalues and eigenvectors of the spatial covariance matrix; the signal subspace and the noise subspace are obtained according to the order of the eigenvalues, and finally the estimated value of the direction of arrival is obtained by seeking the peak value.

[0049] Figure 3 It represents the basic process of the MUSIC software implementation. As Figure 3 , the calculation steps of the angle perception data are as follows:

[0050] Step 1: Obtain the estimated value of the covariance matrix according to N received signal vectors:

[0051]

[0052] where x n represents the signal samples collected by the array elements, with a size of K×1, K represents the number of array elements, and N represents the number of snapshots corresponding to the signal samples collected by the array elements.

[0053] Step 2: Perform singular value decomposition on the covariance matrix obtained above to obtain the eigenvalues and eigenvectors of the spatial covariance matrix:

[0054] X = UDV H

[0055] where U is a matrix of size K×K with orthogonal columns, D is a diagonal matrix of size K×N, and V is a matrix of size N×N with orthogonal columns.

[0056] Step 3: According to the order of the eigenvalues, regard the eigenvectors corresponding to the largest r eigenvalues equal to the number of signals as the signal subspace, and regard the eigenvectors corresponding to the remaining K-r eigenvalues as the noise subspace Q n .

[0057] Step 4: Vary the angle θ by traversing the angle between -90° and 90°, calculate the spectral function according to the following formula, and obtain the estimated value of the direction of arrival of the wave by seeking the peak value, where a(θ) represents the steering vector, and the result corresponding to the steering vector is calculated according to the angle θ:

[0058]

[0059] By finding the local peaks equal to the number of signals, the arrival angle of the beam corresponding to each end user can be estimated.

[0060] Based on the calculated arrival angle of the beam, the angle can be mapped to the corresponding beam direction control word index according to the mapping table provided by the millimeter-wave array manufacturer.

[0061] The millimeter-wave array control information is transmitted to the control module through a custom data packet structure. The data packet structure can be: the first line of the data packet includes the time stamp, channel index, count value of the data packet, length of the data segment, and identification of the data packet; the remaining header lines represent the phased array configuration information of each user, including the configuration time, beam pointing direction of the corresponding user, gain magnitude, current transceiver state, configuration word identification of the millimeter-wave array, and control word valid bit.

[0062] Exemplarily, Figure 4 Schematic diagram of the data packet representing the transmission control word, where the first line of the data packet gives the current time Timestamp, the corresponding channel index CH_ID, the count value seq_cnt of the data packet, the length Length of the data segment in the data packet, and the identification ID corresponding to this data packet, which is defined as 12345678 in 32 bits in this example, where each bit is a hexadecimal value, each occupying 4 bits. The remaining header lines represent the phased array configuration information of each user, where the configuration time is time_stamp_comfig, the beam pointing direction of the corresponding user is BeamV representing the vertical direction, BeamH representing the horizontal direction, APC and AGC represent the gain magnitude, TxON and RxON represent the current transceiver state, Mode is the configuration word identification of the millimeter-wave array, and valid represents the control word valid bit.

[0063] The control module configures the receiving sub-module, the control word transmission timing control sub-module, and the control word transmission sub-module through the control word to control the beam direction of the millimeter-wave array. The control word configuration receiving sub-module receives the beam direction control word from the software processing module and parses the beam direction configuration time, etc.; the control word transmission timing control sub-module makes a time judgment to decide whether to start the control word transmission sub-module; the control word transmission sub-module generates a control signal according to the transmission protocol CusSPI and outputs the control word.

[0064] Figure 5 It illustrates the interaction logic between the low-frequency direction-finding auxiliary array (sensing array) and the millimeter-wave phased array (millimeter-wave array). The control word configuration receiving sub-module receives the beam direction control word calculated by software, and at the same time parses out the beam direction configuration time. This vitatime value (denoted as ve) is compared with the vitatime value on the board (denoted as va). When ve > va, it indicates that the transmission moment has not arrived yet, and continue to wait; when ve = va, it indicates that the transmission moment has arrived, and start the control word transmission module; when ve < va, it indicates that the transmission moment has passed, and start the control word transmission sub-module. The control word transmission sub-module generates a control signal according to the specified transmission protocol and outputs the control word.

[0065] Figure 6 It illustrates the custom control word transmission protocol CusSPI, which communicates with the millimeter-wave array antenna in the form of a bus, including the data signal PSA_DATA, the clock signal PSA_DCLK, the data transmission enable signal PSA_FCLK, and the data latch signal PSA_LE. When the PSA_FCLK signal is at a low level, it indicates the start of data transmission. At the same time, the PSA_DATA data is valid at the rising edge of PSA_DCLK. When the transmission of this frame of data is completed, the PSA_FCLK signal returns to a high level. After a period of delay, the PSA_LE signal issues a positive pulse, indicating that the transmission of this frame of data is completed, and start to configure the millimeter-wave phased array according to the control word.

Claims

1. A device for assisting millimeter-wave communication with low-frequency direction finding, characterized in that It includes a signal generation module, a control module, a data link module, a software processing module, a millimeter-wave array, and a sensing array; The millimeter-wave array is used for the air interface transceiver of communication signals; The sensing array is used for the air interface transceiver of angle sensing signals; The signal generation module is connected to the sensing array and sends the generated sensing signals through the sensing array; The control module is connected to the millimeter-wave array and controls the beam direction of the millimeter-wave array through control configuration information; The data link module is used for receiving sensing data and transmitting angle control information of the millimeter-wave array; The software processing module is used for calculating angle sensing data and generating corresponding millimeter-wave array control information; The sensing signals received by the sensing array are connected to the software processing module via the data link module, and the corresponding sensing angles are calculated through the software processing module. The sensed angles are then transmitted to the millimeter-wave array through the control module.

2. The device for low-frequency direction finding assisted millimeter-wave communication according to claim 1, characterized in that The sensing array and the millimeter-wave array are fixedly connected together. Based on the sensing signals of the sensing array, real-time angle estimation is performed, and the corresponding angle configuration information is filled in the header part through a predefined data packet structure, thereby completing the beam configuration of the millimeter-wave array and realizing real-time control of the beam direction of the millimeter-wave array.

3. The device for low-frequency direction finding assisted millimeter-wave communication according to claim 1, characterized in that, In the software processing module, the low-frequency multiple signal classification algorithm is used for direction finding. First, the estimated value of the covariance matrix is obtained according to the received signal vector, and then the covariance matrix is subjected to singular value decomposition to obtain the eigenvalues and eigenvectors of the spatial covariance matrix; the signal subspace and the noise subspace are obtained according to the order of the eigenvalues, and finally the estimated value of the direction of arrival is obtained by seeking the peak value.

4. The device for low-frequency direction finding assisted millimeter-wave communication according to claim 1, characterized in that, The data packet structure for generating the millimeter-wave array control information in the software processing module is as follows: The first row of the data packet includes a timestamp, a channel index, the count value of the data packet, the length of the data segment, and the identifier of the data packet; the remaining header rows represent the phased array configuration information of each user, including the configuration time, the beam pointing direction of the corresponding user, the gain magnitude, the current transceiver state, the configuration word identifier of the millimeter-wave array, and the control word valid bit.

5. The device for low-frequency direction finding-assisted millimeter-wave communication according to claim 1, wherein The software processing module is also used for parsing communication data, calculating its corresponding signal-to-noise ratio, and performing stability discrimination on the signal-to-noise ratio, thereby generating a quantization criterion for the beam alignment effect.

6. The device for low-frequency direction finding-assisted millimeter-wave communication according to claim 1, characterized in that, The control module includes a control word configuration receiving sub-module, a control word transmission timing control sub-module, and a control word transmission sub-module; The control word configuration receiving sub-module is used for receiving the beam direction control word from the software processing module and parsing the beam direction configuration time; The control word transmission timing control sub-module is used for comparing the configuration time parsed by the control word configuration receiving sub-module, denoted as ve, with the vitatime value on the board, denoted as va. When ve > va, continue to wait; when ve ≤ va, start the control word transmission sub-module; The control word transmission sub-module is used for generating a control signal according to the transmission protocol CusSPI and outputting the control word.

7. The device for low-frequency direction finding assisted millimeter-wave communication according to claim 6, wherein The CusSPI communicates with the millimeter-wave array in the form of a bus, including the data signal PSA_DATA, the clock signal PSA_DCLK, the data transfer enable signal PSA_FCLK, and the data latch signal PSA_LE; when the PSA_FCLK signal is at a low level, it indicates the start of data transfer. At the same time, the PSA_DATA data is valid at the rising edge of PSA_DCLK. When the frame data transfer is completed, the PSA_FCLK signal returns to a high level. After a period of delay, the PSA_LE signal emits a positive pulse, indicating that the frame data transfer is complete and starts to configure the millimeter-wave array according to the control word.

8. A method for low-frequency direction finding assisted millimeter-wave communication, characterized in that, It includes the following steps: The sensing signal generated by the signal generation module is sent out through the sensing array. After the sensing array receives the sensing signal, the software processing module calculates the corresponding sensing angle and generates the corresponding millimeter-wave array control information, which is transmitted to the millimeter-wave array through the control module. After the control module receives the control information obtained according to the sensing angle, it controls the beam direction of the millimeter-wave array through the control configuration information.

9. A method for low-frequency direction finding assisted millimeter-wave communication according to claim 8, characterized in that The data packet structure transmitted between the software processing module and the control module is as follows: the first line of the data packet includes the timestamp, channel index, count value of the data packet, length of the data segment, and identification of the data packet; the remaining header lines represent the phased array configuration information of each user, including the configuration time, beam pointing direction of the corresponding user, gain magnitude, current transceiver state, configuration word identification of the millimeter-wave array, and control word valid bit.

10. A method for low-frequency direction finding assisted millimeter-wave communication according to claim 8, characterized in that The steps for the control module to configure the millimeter-wave array include: Receiving the beam direction control word from the software processing module and parsing the beam direction configuration time. Comparing the configuration time parsed by the control word configuration receiving sub-module, denoted as ve, with the vitatime value on the board, denoted as va. When ve > va, continue to wait; when ve ≤ va, generate a control signal according to the transmission protocol CusSPI and output the control word. The CusSPI communicates with the millimeter-wave array in the form of a bus, including the data signal PSA_DATA, the clock signal PSA_DCLK, the data transfer enable signal PSA_FCLK, and the data latch signal PSA_LE; when the PSA_FCLK signal is at a low level, it indicates the start of data transfer. At the same time, the PSA_DATA data is valid at the rising edge of PSA_DCLK. When the frame data transfer is completed, the PSA_FCLK signal returns to a high level. After a period of delay, the PSA_LE signal emits a positive pulse, indicating that the frame data transfer is complete and starts to configure the millimeter-wave array according to the control word.

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