Distributed signal acquisition and transmission method and device based on FPGA and optical fiber

Abstract

The invention provides a distributed signal collection and transmission method and device based on an FPGA and an optical fiber, and relates to the technical field of signal collection, and the method comprises the steps: collecting a distributed communication signal based on the FPGA, and carrying out the AD sampling, and obtaining a digital communication signal; framing the digital communication signal based on the FPGA, and receiving a timing system signal sent by a timing system slave device; framing and packaging the digital communication signal by adopting a preset transmission protocol according to the timing signal based on the FPGA to obtain a data packet, and transmitting the data packet to a server through an optical fiber by adopting the preset transmission protocol; and receiving the data packet based on the server, and analyzing the data packet through the DPDK to obtain the data packet. According to the method, optical fibers are adopted to transmit timing signals at an acquisition equipment end, framing and timestamp adding are performed after AD sampling digitization, the signals are transmitted to a rear end through the optical fibers, a DPDK technology is adopted at the rear end for data receiving, and the method can be suitable for a large-aperture antenna array wide-area distributed system.

Description

Technical Field

[0001] The present invention relates to the technical field of signal acquisition, and in particular to a distributed signal acquisition and transmission method and device based on FPGA and optical fiber. Background Art

[0002] In synchronous acquisition systems, synchronous data acquisition and high-speed data transmission are the key to ensuring the accuracy and real-time performance of back-end data processing. At present, conventional synchronous acquisition systems usually use a clock source board to fan out multiple clocks to each acquisition board through RF cables. There are usually three acquisition methods: RF direct acquisition, zero intermediate frequency, and superheterodyne. Conventional synchronous acquisition systems require that the RF cables are of equal length and should not be too long, so the clock source board and the acquisition board are close to each other, usually in the same chassis, which is limited for large-aperture antenna array wide-area distributed systems.

[0003] At present, TCP is widely used for data transmission in network communication. The synchronous acquisition system usually transmits the collected signal data to the back-end server or workstation for subsequent array signal analysis and processing, such as DDC (Digital Down Convert), signal identification, direction finding, synthesis, etc. The data flow that needs to be transmitted is huge. How to receive and process data packets within a limited time has become the key to improving the data transmission performance of the synchronous acquisition system.

[0004] Therefore, a new data synchronization acquisition solution is urgently needed. Summary of the invention

[0005] The present invention provides a distributed signal acquisition and transmission method and device based on FPGA and optical fiber, which are used to solve the technical defects in the prior art of distributed deployment of acquisition equipment, huge data transmission flow and insufficient transmission and synchronization performance.

[0006] In a first aspect, the present invention provides a distributed signal acquisition and transmission method based on FPGA and optical fiber, comprising:

[0007] Based on FPGA, distributed communication signals are collected for AD sampling to obtain digital communication signals;

[0008] Frame the digital communication signal based on FPGA, and receive the timing signal sent by the timing slave device;

[0009] Based on the FPGA, the digital communication signal is framed and packaged using a preset transmission protocol according to the timing signal to obtain a data packet, and the data packet is transmitted to the server through an optical fiber using a preset transmission protocol;

[0010] The server receives the data packet, parses it through DPDK to obtain the data packet, and submits the data packet to the application layer for processing.

[0011] According to the distributed signal acquisition and transmission method based on FPGA and optical fiber, the process of receiving the UDP data packet based on the server and obtaining the data packet by parsing through DPDK includes:

[0012] Reload the network card driver with DPDK and initialize the DPDK environment;

[0013] Create a data buffer;

[0014] Create a receive queue and bind it to an isolated CPU core;

[0015] Configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

[0016] According to the distributed signal acquisition and transmission method based on FPGA and optical fiber, after obtaining the data packet, it also includes:

[0017] Copying the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code;

[0018] When the circular buffer is full, the semaphore is released.

[0019] According to the distributed signal acquisition and transmission method based on FPGA and optical fiber, the preset transmission protocol includes TCP protocol and UDP protocol.

[0020] According to the distributed signal acquisition and transmission method based on FPGA and optical fiber, the timing signal includes a sampling clock signal, a time code signal and a PPS signal.

[0021] In a second aspect, the present invention further provides a distributed signal acquisition and transmission system based on FPGA and optical fiber, comprising: a plurality of receivers, a plurality of time-controlled slave devices connected to the receivers via optical fiber, a time-controlled master device connected to the time-controlled slave devices via optical fiber, and a server connected to the receivers via optical fiber;

[0022] The timing master device is used to synchronously transmit timing signals to a plurality of timing slave devices;

[0023] The receiver is used to collect distributed communication signals based on the time system master device for AD sampling to obtain digital communication signals, and receive the time system signals sent by the time system slave device, frame and encapsulate and package them using a preset transmission protocol to obtain data packets, and transmit the data packets to the server through optical fiber using a preset transmission protocol;

[0024] The server is used to receive the data packet, parse the data packet through the DPDK module to obtain the data packet, and submit the data packet to the application layer for processing.

[0025] According to the distributed signal acquisition and transmission system based on FPGA and optical fiber, the time system master device adopts a circuit combining FPGA and optical fiber devices, including:

[0026] AD conversion module, used to collect distributed communication signals for AD sampling;

[0027] A data encapsulation module is used to perform framing and encapsulation and packaging processing using a preset transmission protocol to obtain a data packet;

[0028] A data sending module, used to transmit the data packet to the server via optical fiber using a preset transmission protocol;

[0029] The data buffer module is used to copy the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code; and release the semaphore when the circular buffer is full.

[0030] According to the distributed signal acquisition and transmission system based on FPGA and optical fiber, the DPDK module includes:

[0031] Initialization unit, used to reload the DPDK network card driver and initialize the DPDK environment;

[0032] The data buffer unit is used to create a data buffer area and create a receive queue and bind it to an isolated CPU core;

[0033] The packet capture unit is used to configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

[0034] According to the distributed signal acquisition and transmission system based on FPGA and optical fiber, the time system master device and the time system slave device use the PTP protocol to exchange information.

[0035] According to the distributed signal acquisition and transmission system based on FPGA and optical fiber, the time code interface between the time slave device and the receiver is transmitted via the RS232 serial port;

[0036] The sampling clock interface between the timing slave device and the receiver is transmitted using an SMA radio frequency interface.

[0037] Compared with the conventional synchronous acquisition system, the method provided by the present invention acquires the distributed communication signal based on FPGA for AD sampling to obtain the digital communication signal; frames the digital communication signal based on FPGA, and receives the time signal sent by the time slave device; frames the digital communication signal based on FPGA according to the time signal using a preset transmission protocol and performs encapsulation and packaging processing to obtain a data packet, and transmits the data packet to the server through the optical fiber using the preset transmission protocol; receives the data packet based on the server, obtains the data packet through DPDK analysis, and submits the data packet to the application layer for processing. The method uses optical fiber to transmit the synchronous time signal at the acquisition device end, frames it after digitization through AD sampling, adds a timestamp, transmits it to the back end through the optical fiber, and uses DPDK technology to receive data at the back end, which can be applied to the wide-area distributed system of large-aperture antenna array. The present invention is constructed by combining FPGA and optical fiber, has simple logic, short development cycle, small logic resource occupation, no specific model requirements, only needs to have a high-speed data interface, has low construction cost, effectively realizes data transmission with huge flow, and greatly improves the data transmission performance of the synchronous acquisition system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 This is a schematic diagram of the connection of a time system master and slave device provided by the present invention;

[0040] Figure 2 It is a connection diagram of a receiver and a server provided by the present invention;

[0041] Figure 3 It is a connection diagram of a time system slave device and a receiver provided by the present invention;

[0042] Figure 4 It is a flow chart of the distributed signal acquisition and transmission method based on FPGA and optical fiber provided by the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0045] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0046] DPDK (Data Plane Development Kit) is used to quickly process network data packets. DPDK adopts the zero-copy + polling method. After the network card receives the data packet, the network card driver overloaded by DPDK will not notify the CPU through an interrupt, but directly store the data packet into the memory and deliver it to the application layer software for processing, saving a lot of CPU interrupt overhead and memory copy time.

[0047] Combine the following Figure 1-Figure 4 The invention describes a distributed signal acquisition and transmission method and device based on FPGA and optical fiber provided in an embodiment of the invention.

[0048] The application scenario of the present invention is the synchronous acquisition and high-speed data transmission in a wide-area distributed system with a large aperture antenna array. The receivers in a wide-area distributed system are usually far away and cannot share the clock fanned out by the clock source board. At the same time, the data flow transmitted from the receiver to the server is huge, so how to quickly receive data is the key.

[0049] The present invention provides a distributed signal acquisition and transmission system based on FPGA and optical fiber, which comprises: a plurality of receivers, a plurality of time-controlled slave devices connected to the receivers via optical fibers, a time-controlled master device connected to the time-controlled slave devices via optical fibers, and a server connected to the receivers via optical fibers.

[0050] Figure 1 Schematic diagram of the connection of a master-slave device of a time system provided by the present invention, such as Figure 1 As shown, a timing master device and multiple slave devices communicate via synchronous optical fiber, and the master device transmits synchronous sampling clock, time code and second pulse to the slave devices.

[0051] Figure 2 A connection diagram of a receiver and a server provided by the present invention. The receiver and the server are directly connected via a data optical fiber.

[0052] Preferably, to improve network transmission efficiency, both the receiver and the server network card can be set to jumbo frame mode (MTU is set to 9000).

[0053] Figure 3 The schematic diagram of the connection between the time system slave device and the receiver provided by the present invention. After the time system slave device receives the sampling clock, PPS and time code from the time system master device, in a preferred embodiment, a four-channel receiver is used, the sampling clock is connected to the receiver through the SMA radio frequency interface, the PPS is connected to the receiver through the SMA radio frequency interface, and the time code is connected to the receiver through the RS232 serial port.

[0054] Preferably, the time system master device adopts a circuit combining FPGA and optical fiber devices, including:

[0055] AD conversion module, used to collect distributed communication signals for AD sampling;

[0056] A data encapsulation module is used to perform framing and encapsulation and packaging processing using a preset transmission protocol to obtain a data packet;

[0057] A data sending module, used to transmit the data packet to the server via optical fiber using a preset transmission protocol;

[0058] The data buffer module is used to copy the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code; and release the semaphore when the circular buffer is full.

[0059] Preferably, the DPDK module includes:

[0060] Initialization unit, used to reload the DPDK network card driver and initialize the DPDK environment;

[0061] The data buffer unit is used to create a data buffer area and create a receive queue and bind it to an isolated CPU core;

[0062] The packet capture unit is used to configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

[0063] Preferably, the PTP protocol is used for information exchange between the time system master device and the time system slave device.

[0064] Preferably, the sampling clock interface between the timing slave device and the receiver is transmitted using an SMA radio frequency interface.

[0065] Figure 4 FIG. 1 is a flow chart of a distributed signal acquisition and transmission method based on FPGA and optical fiber provided by the present invention, such as Figure 4 As shown, including but not limited to the following steps:

[0066] S102: collecting distributed communication signals based on FPGA to perform AD sampling to obtain digital communication signals;

[0067] S104: framing the digital communication signal based on the FPGA, and receiving a timing signal sent by a timing slave device;

[0068] S106: framing and encapsulating the digital communication signal according to the timing signal using a preset transmission protocol based on the FPGA to obtain a data packet, and transmitting the data packet to the server through an optical fiber using the preset transmission protocol;

[0069] S108: The server receives the data packet, parses the data packet through DPDK, and submits the data packet to the application layer for processing.

[0070] The preset transmission protocol includes TCP protocol and UDP protocol. The time signal includes a sampling clock signal, a time code signal and a PPS signal.

[0071] In this embodiment, the timing master device and the timing slave device are interconnected through synchronous optical fiber; the receiver and the server are interconnected through data optical fiber; the timing slave device provides the receiver with timing signals such as sampling clock, time code and PPS; the receiver obtains the collected communication signal through AD sampling to obtain a digital communication signal, completes data framing and timestamping in FPGA according to the timing signal, and transmits it to the back-end server through the high-speed data port via the optical fiber interface and the preset transmission protocol; the back-end server reloads the network card driver and is set to receive data packets through DPDK technology; after receiving the data packet, DPDK submits the data packet to the application layer, temporarily stores it in the memory, and then performs subsequent signal processing operations according to specific functional requirements.

[0072] Preferably, according to the needs of different signal processing algorithms, a circular cache queue of fixed size and number can be constructed in the server memory. After DPDK receives a data packet, it stores it in the circular cache queue according to the timestamp in the packet. Whenever the circular cache is full, other modules are notified for processing through semaphores and other means.

[0073] Based on the contents of the above embodiments, in a preferred embodiment, in the distributed signal acquisition and transmission method based on FPGA and optical fiber provided by the present invention, the process of receiving the UDP data packet based on the server and obtaining the data packet by parsing through DPDK includes:

[0074] Reload the network card driver with DPDK and initialize the DPDK environment;

[0075] Create a data buffer;

[0076] Create a receive queue and bind it to an isolated CPU core;

[0077] Configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

[0078] Based on the contents of the above embodiments, in a preferred embodiment, in the distributed signal acquisition and transmission method based on FPGA and optical fiber provided by the present invention, after obtaining the data packet, it also includes:

[0079] Copying the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code;

[0080] When the circular buffer is full, the semaphore is released.

[0081] The following is a specific embodiment of the distributed signal acquisition and transmission method based on FPGA and optical fiber provided by the present invention, and the steps of the embodiment are as follows:

[0082] Step 1: In a four-channel receiver, the signal received by the antenna is filtered, amplified, and directly sent to the ADC for sampling.

[0083] Step 2: FPGA performs UDP framing on the data sampled by the multi-channel ADC.

[0084] Step 3: FPGA timestamps the UDP data packet based on the PPS and time code transmitted from the timing slave device.

[0085] Step 4: FPGA sends the timestamped UDP data packet to the backend server through the high-speed port and then the optical fiber interface.

[0086] Step 5: Set CPU core isolation in the backend server kernel startup command line, so that it is not scheduled by the operating system kernel, and allocate large page memory.

[0087] Step 6: The backend server sets DPDK to reload the network card driver and initialize the DPDK environment.

[0088] Step 7: The backend server creates mbufs, and the size of each mbuf is set to be larger than the maximum packet size.

[0089] Step 8: The backend server creates an RX queue and binds it to the isolated CPU core of the server.

[0090] Step 9: Set the network card on the backend server to enable promiscuous mode.

[0091] Step 10: The backend server starts packet capture and copies the data packet to the cache corresponding to the circular cache queue according to the corresponding time code;

[0092] Step 11: When the circular buffer is full, the semaphore is released and other modules are notified to process;

[0093] In this embodiment, the receiver is equipped with a constant temperature crystal oscillator. When the sampling clock of the time slave device is interrupted, it is automatically switched to the internal crystal oscillator for ADC sampling. When the sampling clock of the time slave device is restored, the sampling clock of the time slave device is automatically used as the ADC clock. In actual testing, 6.6 Gbps stable transmission without packet loss can be achieved under a 10 Gigabit network.

[0094] The FPGA of the present invention has simple logic, short development cycle, small occupation of logic resources, no specific model requirements, and only needs to have a high-speed data interface.

[0095] In summary, the distributed signal acquisition and transmission method and system based on FPGA and optical fiber provided by the present invention, compared with the conventional synchronous acquisition system, uses optical fiber to transmit the synchronous sampling clock, PPS and time code at the acquisition device end, digitalizes through AD sampling, frames, adds timestamps, transmits to the back end through optical fiber, and uses DPDK technology for data reception at the back end, which can be applied to the wide-area distributed system of large-aperture antenna arrays. In actual testing, four four-channel direct acquisition receivers were connected to a server, and 4*6.6Gbps stable transmission without packet loss could be achieved under the 10G network.

[0096] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0097] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed signal acquisition and transmission method based on FPGA and optical fiber, characterized in that: include: Based on FPGA, distributed communication signals are collected for AD sampling to obtain digital communication signals; Frame the digital communication signal based on FPGA, and receive the timing signal sent by the timing slave device; Based on the FPGA, the digital communication signal is framed and packaged using a preset transmission protocol according to the timing signal to obtain a data packet, and the data packet is transmitted to the server through an optical fiber using a preset transmission protocol; The server receives the data packet, parses it through DPDK to obtain the data packet, and submits the data packet to the application layer for processing.

2. The distributed signal acquisition and transmission method based on FPGA and optical fiber according to claim 1 is characterized in that: The process of receiving the UDP data packet based on the server and parsing the data packet through DPDK includes: Reload the network card driver with DPDK and initialize the DPDK environment; Create a data buffer; Create a receive queue and bind it to an isolated CPU core; Configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

3. The distributed signal acquisition and transmission method based on FPGA and optical fiber according to claim 2 is characterized in that: After obtaining the data packet, the method further includes: Copying the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code; When the circular buffer is full, the semaphore is released.

4. The distributed signal acquisition and transmission method based on FPGA and optical fiber according to claim 2 is characterized in that: The preset transmission protocol includes TCP protocol and UDP protocol.

5. The distributed signal acquisition and transmission method based on FPGA and optical fiber according to claim 1, characterized in that: The timing signal includes a sampling clock signal, a time code signal and a PPS signal.

6. A distributed signal acquisition and transmission system based on FPGA and optical fiber, characterized in that: include: A plurality of receivers, a plurality of time system slave devices connected to the receivers via optical fibers, a time system master device connected to the time system slave devices via optical fibers, and a server connected to the receivers via optical fibers; The timing master device is used to synchronously transmit timing signals to a plurality of timing slave devices; The receiver is used to collect distributed communication signals based on the time system master device for AD sampling to obtain digital communication signals, and receive the time system signals sent by the time system slave device, frame and encapsulate and package them using a preset transmission protocol to obtain data packets, and transmit the data packets to the server through optical fiber using a preset transmission protocol; The server is used to receive the data packet, parse the data packet through the DPDK module to obtain the data packet, and submit the data packet to the application layer for processing.

7. The distributed signal acquisition and transmission system based on FPGA and optical fiber according to claim 6, characterized in that: The timing master device adopts a circuit combining FPGA and optical fiber devices, including: AD conversion module, used to collect distributed communication signals for AD sampling; A data encapsulation module is used to perform framing and encapsulation and packaging processing using a preset transmission protocol to obtain a data packet; A data sending module, used to transmit the data packet to the server via optical fiber using a preset transmission protocol; The data buffer module is used to copy the data packet to the buffer corresponding to the circular buffer queue according to the corresponding time code; and release the semaphore when the circular buffer is full.

8. The distributed signal acquisition and transmission system based on FPGA and optical fiber according to claim 6, characterized in that: The DPDK modules include: Initialization unit, used to reload the DPDK network card driver and initialize the DPDK environment; The data buffer unit is used to create a data buffer area and create a receive queue and bind it to an isolated CPU core; The packet capture unit is used to configure the network card to enable promiscuous mode and start packet capture to obtain data packets.

9. The distributed signal acquisition and transmission system based on FPGA and optical fiber according to claim 6, characterized in that: The PTP protocol is used to exchange information between the time system master device and the time system slave device.

10. The distributed signal acquisition and transmission system based on FPGA and optical fiber according to claim 6, characterized in that: The time code interface between the time system slave device and the receiver is transmitted via the RS232 serial port; The sampling clock interface between the timing slave device and the receiver is transmitted using an SMA radio frequency interface.

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