A K-band aviation cluster collaborative detection low-latency transmission method and device

Abstract

The invention discloses a K-band aviation cluster cooperative detection low-latency transmission method and device, belonging to the technical field of K-band electronic warfare cooperative passive detection. The transmission device comprises a cooperative passive detection information processing module, a link processing module, a baseband processing module, a digital-to-analog conversion module, an analog-to-digital conversion module, a radio frequency transmission module, a radio frequency receiving module, a co-site filter and a directional antenna, which can realize real-time interaction of passive detection positioning cooperative information and improve the detection accuracy of the system; and the frame format is short and insensitive to time-varying channels, which is suitable for large-maneuverability and high-dynamic air-to-air mobile communication scenarios; the low-latency signal receiving and sending processing method is based on the cooperative passive detection system, and can analyze the factors causing information transmission delay one by one according to the working environment; the transmission delay of the signal can be compressed to the maximum extent by adopting measures such as optimizing the time frame structure and a high-efficiency encoding and decoding algorithm, which solves the problem that the existing airborne data link system cannot meet the index requirements during transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of K-band electronic warfare cooperative passive detection technology, and in particular to a K-band aviation cluster cooperative detection low-latency transmission method and device. Background Art

[0002] Communication delay, also known as latency, is the time it takes for a unit data signal to reach the other end of a data circuit from one end. It is a real-time indicator of an aviation cluster interactive network. The communication delay of an aviation cluster interactive network consists of propagation delay, processing delay, transmission delay, and waiting delay. The propagation delay is limited by the propagation distance and the speed of electromagnetic waves and cannot be optimized; the transmission delay is mainly determined by the transmission rate and the size of the data packet, and a suitable transmission rate needs to be selected; the waiting delay is mainly limited by the access control protocol, and a reasonable MAC protocol needs to be designed; the processing delay is related to the signal processing speed, the complexity of the algorithm, and the frame format design. How to reduce the processing delay is the key issue to be considered in this invention.

[0003] Among the three major application scenarios of 5G mobile communications in civil systems, there is an application scenario for low-latency transmission. In the military aviation cluster interactive network system, the requirements for latency are also very strict. Systems with low-latency transmission are called real-time systems, but different types of networks have different requirements for real-time performance. For example: the communication delay of a general intelligence communication network is at the minute level; the tactical command-level aviation communication network is a quasi-real-time system with a communication delay of seconds; and the weapon control-level aviation cluster interactive network has higher real-time requirements, and its communication delay is at the millisecond level. The electronic warfare collaborative passive detection system has higher requirements for the real-time performance of information transmission, reaching the sub-millisecond level. The communication delay determines the performance of the electronic warfare system, especially the passive detection positioning accuracy. When the delay is large to a certain extent, the entire collaborative detection will fail. The electronic warfare cooperative passive detection system works in the K band. When the cooperative passive detection system is applied to a multi-node cooperative aerial platform, it faces the problems of large maneuverability and high dynamics in the application. At this time, the detection information between the nodes needs to be interacted in a very short time under the condition of synchronization. The current indicator requires less than 420μs, otherwise the passive target detection accuracy is greatly reduced and the function cannot be realized. There is no report on the low-latency information transmission device working under this band condition. The transmission delay of the existing airborne data link system in other bands is in the second level, which cannot meet the indicator requirements.

[0004] Therefore, developing a low-latency transmission method for K-band aviation cluster collaborative detection has great application value. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention aims to provide a low-latency transmission method and device for collaborative detection of a K-band aviation cluster. This method is based on the collaborative passive detection system itself. By reducing the collaborative information transmission delay as the purpose, according to the working environment of the system, the factors causing the information transmission delay are analyzed one by one, and comprehensive measures such as optimizing the time frame structure, increasing the interface transmission rate, and high-efficiency encoding and decoding algorithms are adopted. It can compress the signal transmission delay to the maximum extent, and effectively improve the reliability and anti-destruction ability of the system.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A K-band aviation cluster cooperative detection low-latency transmission device, the device is placed in a communication node of a cooperative passive detection system, comprising

[0008] The cooperative passive detection information processing module is the host computer of the low-latency transmission device, which is used to complete the passive detection task information processing and transmit the local node information to the cooperative node;

[0009] Link processing module, used to complete link layer processing of task information;

[0010] Baseband processing module, used to complete data encoding and decoding, modulation and demodulation, framing, capture and synchronization signal transmission processing;

[0011] The digital-to-analog conversion module is connected to the baseband processing module and is used to configure the sampling rate, interpolation mode, and band selection through the baseband processing module to realize the conversion of digital signals into intermediate frequency analog signals and output intermediate frequency analog signals;

[0012] The analog-to-digital conversion module is used to receive the intermediate frequency analog signal from the radio frequency receiving module, convert it into a digital signal and output it to the baseband digital processing module for signal demodulation and timing error estimation;

[0013] The RF transmission module is used to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, and amplification.

[0014] The RF receiving module is used to receive the RF signal from the directional antenna and convert it into an intermediate frequency analog signal output through mixing, filtering and amplification;

[0015] Co-site filter, used to isolate the signal transmission and reception;

[0016] The directional antenna is used to receive the K-band RF signal from the RF transmitting module and transmit it, and at the same time receive the K-band RF signal sent by other nodes and output it to the RF receiving module.

[0017] As a preferred embodiment, when the baseband processing module performs data processing, the data part information processing process in a time slot includes:

[0018] Enter the text source. The source has 32 bytes of data, totaling 256 bits, including 2 bits for channel indication and 254 bits for low-latency service data.

[0019] Then LDPC encoding is performed, and the encoded data is mapped through BPSK to obtain 768 data symbols;

[0020] The pilot sequence is then inserted to carry a total of 1536 modulation symbols.

[0021] As a preferred embodiment, when the baseband processing module performs signal transmission processing, the frame format of the low-latency signal is

[0022] (1) Message Definition

[0023]

[0024] The low-latency data message format is shown in the table above. The length of each data packet is 256 bits. Bit 0 and bit 1 indicate the channel indication. Bit 2 to bit 255 indicate the low-latency task information. If the task data length is less than 254 bits, zeros are added to the end.

[0025] (2) Physical layer frame

[0026] The low-latency physical layer data structure includes synchronization burst and data burst. The synchronization burst length is 80μs and the data burst length is 160μs. The synchronization burst consists of 8 pseudo-random codes with a length of 64 chips. The data burst consists of data field 0, pilot sequence 3, and data field 1.

[0027] Among them, data field 0 has 384 chips, pilot sequence 3 has 128 chips, and data field 1 has 384 chips.

[0028] As a preferred implementation scheme, the passive detection system includes three communication nodes, each communication node is equipped with two directional antennas to generate two independent transmit and receive channels. A dedicated channel is established for uplink and downlink communications between all communication nodes through space division + frequency division, and low-latency task information is sent immediately after being prepared.

[0029] As a preferred implementation scheme, the processing delay of the passive detection system data is no more than 353 μs.

[0030] A low-latency signal receiving and sending processing method includes a data receiving process and a data sending process. The data receiving process includes

[0031] Step 1: Use the directional antenna to receive the K-band RF signal from the RF transmitting module and transmit it, and at the same time receive the K-band RF signal sent by other nodes and output it to the RF receiving module;

[0032] Step 2: Use co-site filters to isolate signal transmission and reception;

[0033] Step 3: Use the RF receiving module to receive the RF signal from the directional antenna, and convert it into an intermediate frequency analog signal output through mixing, filtering, and amplification;

[0034] Step 4: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the baseband processing module for signal demodulation and timing error estimation;

[0035] Step 5: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and transmit it synchronously to the link processing module after processing;

[0036] Step 6: Use the link processing module to perform link layer processing of the task information, and send the task information to the cooperative passive detection information processing module after processing;

[0037] Step 7: Use the cooperative passive detection information processing module to process the passive detection task information and transmit the local node information to the cooperative node.

[0038] As a preferred implementation scheme, the data sending process includes:

[0039] Step 1: After the cooperative passive detection information processing module processes the passive detection task information, it sends it to the link processing module;

[0040] Step 2: Use the link processing module to perform link layer processing of the task information, and send the task information to the baseband processing module after processing;

[0041] Step 3: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and synchronously transmit it to the analog-to-digital conversion module after processing;

[0042] Step 4: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the RF structure module;

[0043] Step 5: Use the RF transmitter module to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, and amplification.

[0044] As a preferred embodiment, the data receiving process in the baseband processing module includes:

[0045] When receiving, the signal is down-converted and the receiving channel is in the capture state by default, searching and capturing the signal;

[0046] When the capture is completed, the bit synchronization and frequency deviation data are extracted from the frame header, and then the carrier synchronization and timing synchronization of the signal are performed. After the synchronization is completed, the BPSK signal is demodulated. The demodulation adopts the method of extracting soft information and quantizing 8 bits.

[0047] The data is input to the LDPC decoding module. The LDPC decoding adopts a parallel quantization layered simplified decoding algorithm with offset, and the number of decoding iterations is set to 6.

[0048] As a preferred embodiment, the data transmission process in the baseband processing module includes:

[0049] When sending, when the task data packet is received, the data sending process is started, and the frame header and source data are processed in parallel. The frame header performs BPSK modulation on the synchronization code, and the source data completes grouping, LDPC coding and BPSK modulation. The LDPC coding uses a segmented coding algorithm to first eliminate the Gaussian elements of the check matrix;

[0050] Then the matrix P and the information bit S are divided. When storing, each segment of the matrix P is combined into a data and stored in the corresponding memory. When encoding, the segmented data is taken out and the encoding operation is performed with the segmented information bit.

[0051] Then the frame is formed, and the digital up-conversion is sent to the digital-to-analog conversion module and transmitted through the transmission channel.

[0052] As a preferred embodiment, the process of link layer processing of task information by the link processing module includes:

[0053] In low-latency mode, the link processing module only detects the channel selection bit and directly sends the user data to the corresponding channel for processing based on the channel selection;

[0054] The working clock is 256MHz. Channel selection and judgment requires 2 clocks, data transparent transmission requires 2 clocks, and a total of 4 processing clocks are required.

[0055] The beneficial effects of the present invention are as follows: the present invention discloses a K-band aviation cluster collaborative detection low-latency transmission method and device. Compared with the prior art, the improvements of the present invention are:

[0056] 1. The present invention proposes a low-delay signal receiving and sending processing method. The method is based on the cooperative passive detection system itself, with the purpose of reducing the cooperative information transmission delay. According to the working environment of the system, the factors causing the information transmission delay are analyzed one by one, and comprehensive measures such as optimizing the time frame structure, improving the interface transmission rate, and high-efficiency encoding and decoding algorithms are adopted to compress the signal transmission delay to the maximum extent.

[0057] 2. The present invention designs a K-band aviation cluster collaborative detection low-latency transmission device, which can realize real-time interaction of passive detection and positioning collaborative information when in use, greatly improving the detection accuracy of the system; at the same time, since the frame format is very short and is insensitive to time-varying channels, it is very suitable for highly maneuverable and highly dynamic air-to-air mobile communication scenarios, thereby improving the reliability and anti-destruction capabilities of the system; it solves the problem that there is currently no report on providing information low-latency transmission devices working under this band condition, and the transmission delay of existing airborne data link systems in other bands is at the second level, which cannot meet the index requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a system structure diagram of the collaborative passive detection system of the present invention.

[0059] Figure 2 This is a structural principle diagram of the K-band aviation cluster collaborative detection low-latency transmission device of the present invention.

[0060] Figure 3 This is a diagram of the physical layer data frame format of the present invention.

[0061] Figure 4 This is a flow chart of information processing of the data portion of the present invention.

[0062] Figure 5 This is a low-latency data transmission interface diagram for the collaborative processing module of the present invention.

[0063] Figure 6 This is a timing diagram of low-latency data input of the collaborative processing module of the present invention.

[0064] Figure 7 This is a timing diagram of the low-latency data transmission output of the collaborative processing module of the present invention.

[0065] Figure 8 This is a main data processing flow chart of the baseband processing module of the present invention.

[0066] Fig. 9 The present invention is a flowchart of the received signal synchronization software design.

[0067] Fig.10 This is the LDPC decoding flow chart of the present invention.

[0068] Fig.11This is a data processing delay analysis diagram in the low-latency data transmission mode of the present invention. DETAILED DESCRIPTION

[0069] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0070] Embodiment 1: refer to the attached Figure 1-Figure 7 As shown, this embodiment provides: a K-band aviation cluster collaborative detection low-latency transmission device, whose structure diagram is as shown Figure 1 As shown in the figure, the communication nodes for aviation cluster collaborative detection all include K-band wireless transmission low-latency transmission devices with the same structure, and each K-band aviation cluster collaborative detection low-latency transmission device includes a collaborative passive detection information processing module, a link processing module, a baseband processing module, a digital-to-analog conversion module, an analog-to-digital conversion module, a radio frequency transmission module, a radio frequency receiving module, a co-site filter and a directional antenna; wherein

[0071] The collaborative passive detection information processing module is used to complete the passive detection task information processing, fuse the task information transmitted by other nodes with the task information perceived locally, complete the passive detection of the target, and transmit the information perceived by this node to other collaborative detection nodes, which belongs to the host computer of the low-latency transmission device;

[0072] The link processing module is used to complete the link layer processing of task information. The specific functions are: first, receiving the task information sent by the cooperative passive detection information processing module, adding a link layer header, and then sending it to the baseband processing module; second, parsing the link layer header of other node information transmitted by the baseband processing module, and then transmitting the unpacked task information to the cooperative passive detection information processing module; third, completing link access management, using the Aloha protocol; fourth, completing the control of the directional antenna;

[0073] The baseband processing module is the core component of the device, which is used to complete the signal transmission processing functions such as data encoding and decoding, modulation and demodulation, framing, capture, synchronization, etc. A high clock is used in this module, and the signal processing clock rate is 256MHz. Comprehensive measures are adopted to complete the low-delay processing of the signal from the perspective of the system;

[0074] The digital-to-analog conversion module is connected to the baseband processing module, and is used to configure the sampling rate, interpolation mode, and band selection through the baseband processing module to realize the conversion of digital signals into intermediate frequency analog signals and output intermediate frequency analog signals;

[0075] The analog-to-digital conversion module is used to receive the intermediate frequency analog signal from the radio frequency receiving module, convert it into a digital signal by bandpass sampling processing, and output it to the baseband digital processing module, and the baseband digital processing module performs signal demodulation and timing error estimation;

[0076] The RF transmission module is used to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, amplification and other processing;

[0077] The RF receiving module is used to receive the RF signal from the directional antenna and convert it into an intermediate frequency analog signal output through mixing, filtering, amplification and other processing;

[0078] The co-site filter is used to isolate the signal transmission and reception, and the system adopts the method of transmitting and receiving at different frequencies to minimize the network access delay;

[0079] The directional antenna is used to receive and transmit K-band radio frequency signals from the radio frequency transmitting module. In addition, it can also receive K-band radio frequency signals sent by other nodes and output them to the radio frequency receiving module.

[0080] As a preferred implementation scheme, when the baseband processing module completes the signal transmission processing functions such as data encoding and decoding, modulation and demodulation, framing, capture, and synchronization, the frame format of the low-latency signal is designed as follows:

[0081] (1) Message Definition

[0082] The low-latency data message format is shown in Table 1; each data packet is 256 bits long; bit0 and bit1 represent channel indication, which is used to distinguish which directional antenna is used for transmission and reception; bit2 to bit255 represent low-latency task information. If the task data length is less than 254 bits, zeros should be added at the end.

[0083] Table 1: Low latency data message format

[0084]

[0085] (2) Physical layer frame

[0086] The low-latency physical layer data frame format is as follows Figure 3As shown in the figure, the data structure consists of two parts: synchronization burst and data burst. The length of synchronization burst is 80μs, and the length of data burst is 160μs. The synchronization burst consists of 8 pseudo-random codes with a length of 64 chips, which are used to achieve the capture and synchronization of low-latency signals. The data burst consists of three parts: data field 0 (384 chips), pilot sequence 3 (128 chips), and data field 1 (384 chips). The data field is used to carry the low-latency service data provided by the system, and the pilot sequence is used to achieve phase synchronization.

[0087] The information processing flow of the data part in a time slot is as follows: Figure 4 As shown in the figure, the source has 32 bytes of data, totaling 256 bits, including 2 bits for channel indication and 254 bits for low-latency service data. Then, LDPC (768, 256) encoding is performed. The encoded data is mapped by BPSK to obtain 768 data symbols, and then the pilot sequence is inserted, carrying a total of 1536 modulation symbols. The symbol rate is 6.4Mbps, the coding efficiency is 1 / 3 of the LPDPC coding, and the shaping factor of the BPSK modulation is 0.35.

[0088] As a preferred implementation scheme, the interface design and cross-linking relationship between the collaborative passive detection information processing module, link processing module, baseband processing module, digital-to-analog conversion module, analog-to-digital conversion module, radio frequency transmission module, radio frequency receiving module, co-site filter and directional antenna are as follows:

[0089] The low-latency data interface is an LVDS signal, which complies with the ANSI / TIA / EIA-644 standard specification. The baseband processing module is connected to the link processing module, and the link processing module is connected to the collaborative passive detection information processing module. A packet of low-latency data needs to be transmitted through four levels of interfaces from sending to receiving. In low-latency mode, the link module uses this interface for fast data input and output to reduce the data interface transmission delay. The interface clock rate is 100MHz, and it adopts DDR dual-edge drive, and the data bit width is 2bit. Among them, the low-latency data interface includes LVDS_TDLY_IClk, LVDS_TDLY_In1, LVDS_TDLY_In2, three-wire LVDS reception; LVDS_TDLY_OClk, LVDS_TDLY_Out1, LVDS_TDLY_Out2 three-wire LVDS transmission, a total of six pairs of LVDS signals; the same processing FPGA transparently transmits the signal for processing; the specific cross-linking relationship is as follows Figure 5 As shown; the timing diagram of the interface is as follows Figure 6 and Figure 7 As shown; the data rate of the interface is 100Mbps, so the transmission delay of each level of the interface is 256 / 2 / 100=1.28μs.

[0090] Based on the above-mentioned K-band aviation cluster collaborative detection low-latency transmission device, a collaborative passive detection system is formed. The collaborative passive detection system consists of three nodes, each node is equipped with two directional antennas, and two independent transceiver channels are generated; a dedicated channel is established for uplink and downlink communications between all nodes of collaborative detection by adopting the space division + frequency division method, and the low-latency task information is sent immediately after it is ready, without waiting for the network; the waiting delay is eliminated to the greatest extent.

[0091] Example 2: Refer to the attached Figure 8-Figure 10 As shown, different from Example 1, this embodiment provides: a method for transmitting and receiving low-latency signals of a low-latency transmission device based on the K-band aviation cluster collaborative detection as described in Example 1

[0092] The transmission processing of low-latency signals is analog signal processing in the digital-to-analog conversion module, the transmission channel module, the co-site filter and the directional antenna. The reception processing of low-latency signals is also analog signal processing in the analog-to-digital conversion module, the receiving channel module, the co-site filter and the directional antenna. The data delay is less than 1μs, and the space for optimization is small. The delay is obtained through the test of the actual system and no special processing is required. The low-latency optimization processing method mainly focuses on the link processing module, the baseband processing module and the interface protocol between the modules; it includes a data receiving process and a data sending process, wherein the specific processing method of the data receiving process is as follows:

[0093] Step 1: Use the directional antenna to receive the K-band RF signal from the RF transmitting module and transmit it, and at the same time receive the K-band RF signal sent by other nodes and output it to the RF receiving module;

[0094] Step 2: Use co-site filters to isolate signal transmission and reception;

[0095] Step 3: Use the RF receiving module to receive the RF signal from the directional antenna, and convert it into an intermediate frequency analog signal output through mixing, filtering, and amplification;

[0096] Step 4: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the baseband processing module for signal demodulation and timing error estimation;

[0097] Step 5: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and transmit it synchronously to the link processing module after processing;

[0098] Step 6: Use the link processing module to perform link layer processing of the task information, and send the task information to the cooperative passive detection information processing module after processing;

[0099] Step 7: Use the cooperative passive detection information processing module to process the passive detection task information and transmit the local node information to the cooperative node.

[0100] The specific processing method of the data receiving process is as follows:

[0101] Step 1: After the cooperative passive detection information processing module processes the passive detection task information, it sends it to the link processing module;

[0102] Step 2: Use the link processing module to perform link layer processing of the task information, and send the task information to the baseband processing module after processing;

[0103] Step 3: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and synchronously transmit it to the analog-to-digital conversion module after processing;

[0104] Step 4: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the RF structure module;

[0105] Step 5: Use the RF transmitter module to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, and amplification.

[0106] As a preferred solution, the data processing flow in the baseband processing module is as follows: Figure 8 As shown, it is divided into two parts: sending process and receiving process;

[0107] (1) In the sending part, when a task data packet is received, the data sending process is started, and the frame header and source data are processed in parallel. The frame header is BPSK modulated by the synchronization code; the source data is grouped, LDPC encoded and BPSK modulated. The LDPC encoding uses a segmented coding algorithm to first perform Gaussian elimination on the check matrix, and then divide the matrix P and the information bit S. When storing, each segment of the matrix P is combined into a data and stored in the corresponding memory. When encoding, the segmented data is taken out and encoded with the segmented information bit.

[0108] Then according to Figure 2 The format shown is framed, and then digitally up-converted and sent to the digital-to-analog conversion module, and then transmitted through the transmission channel. The entire transmission processing process is tested to be 10μs.

[0109] (2) Receiving part: During reception, the signal is down-converted and the receiving channel is in the capture state by default, searching and capturing the signal. The specific capture algorithm is as follows: Fig. 9As shown in the figure, the parallel capture method is adopted. Although this method consumes more logic resources, it can improve the capture performance and reduce the capture time. While completing the capture, the bit synchronization and frequency deviation data are extracted from the frame header, and then the carrier synchronization and timing synchronization of the signal are performed. After the synchronization is completed, the BPSK signal is demodulated. The demodulation adopts the method of extracting soft information and quantizing 8 bits; it is input to the LDPC decoding module. The processing flow chart of the LDPC decoding module is shown in the figure. Fig.10 As shown, LDPC decoding adopts a parallel quantized hierarchical simplified decoding algorithm with offset. Although this algorithm sacrifices some decoding performance, it can greatly reduce the decoding time while meeting the performance requirements. The number of decoding iterations is set to 6 times. By selecting a reasonable decoding method, the decoding time can be controlled within 100μs.

[0110] It should also be noted that in the low-latency transmission mode, the protection interval and block interleaving are removed in order to reduce the deinterleaving delay and select a shorter LDPC code. These comprehensive measures also reduce the decoding delay.

[0111] As a preferred solution, the process of link layer processing of task information by the link processing module includes:

[0112] In low-latency mode, the link processing module does not parse the user data, but only detects the channel selection bit. According to the channel selection, the user data is directly sent to the corresponding channel for processing, minimizing the processing delay. The working clock is 256MHz, the channel selection decision requires 2 clocks, and the data transparent transmission requires 2 clocks, a total of 4 processing clocks, or 15.625ns, are required. Therefore, the processing delay of the link processing module does not exceed 20ns and can be ignored.

[0113] Example 3: Refer to the attached Fig.11 As shown, in order to verify that the K-band aviation cluster collaborative detection low-latency transmission device described in Example 1 is sufficient to meet the design requirements, this embodiment is designed to perform low-latency signal delay analysis on it.

[0114] (1) Design indicators and boundary conditions

[0115] The system design indicators and boundary conditions are to meet the requirement of transmitting 256 bits of data in 420μs.

[0116] (2) Low latency experimental analysis

[0117] The data processing delay (link processing part) analysis process is as follows Fig.11 As shown, the total data transmission delay is:

[0118] Data frame length + up-conversion processing delay + RF transmission delay + down-conversion processing delay + FPGA processing pipeline delay + decoding delay + interface output delay.

[0119] In summary, it can be concluded that the data processing delay is no more than 353μs and less than 420μs, which meets the system indicator requirements.

[0120] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A K-band aviation cluster collaborative detection low-latency transmission device, characterized in that: The device is placed in a communication node of a cooperative passive detection system, and includes The cooperative passive detection information processing module is the host computer of the low-latency transmission device, which is used to complete the passive detection task information processing and transmit the local node information to the cooperative node; Link processing module, used to complete link layer processing of task information; Baseband processing module, used to complete data encoding and decoding, modulation and demodulation, framing, capture and synchronization signal transmission processing; The digital-to-analog conversion module is connected to the baseband processing module and is used to configure the sampling rate, interpolation mode, and band selection through the baseband processing module to realize the conversion of digital signals into intermediate frequency analog signals and output intermediate frequency analog signals; The analog-to-digital conversion module is used to receive the intermediate frequency analog signal from the radio frequency receiving module, convert it into a digital signal and output it to the baseband digital processing module for signal demodulation and timing error estimation; The RF transmission module is used to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, and amplification. The RF receiving module is used to receive the RF signal from the directional antenna and convert it into an intermediate frequency analog signal output through mixing, filtering and amplification; Co-site filter, used to isolate the signal transmission and reception; Directional antenna, used to receive K-band RF signals from the RF transmitting module and transmit them out, and at the same time receive K-band RF signals sent by other nodes and output them to the RF receiving module; When the baseband processing module performs data processing, the data part information processing process in a time slot includes: Enter the text source. The source has 32 bytes of data, totaling 256 bits, including 2 bits for channel indication and 254 bits for low-latency service data. Then LDPC encoding is performed, and the encoded data is mapped through BPSK to obtain 768 data symbols; Then insert the pilot sequence, carrying a total of 1536 modulation symbols; When the baseband processing module performs signal transmission processing, the frame format of the low-latency signal is (1) Message Definition The low-latency data message format is shown in the table above. The length of each data packet is 256 bits. Bit 0 and bit 1 indicate the channel indication. Bit 2 to bit 255 indicate the low-latency task information. If the task data length is less than 254 bits, zeros are added to the end. (2) Physical layer frame The low-latency physical layer data structure includes synchronization burst and data burst. The synchronization burst length is 80μs and the data burst length is 160μs. The synchronization burst consists of 8 pseudo-random codes with a length of 64 chips. The data burst consists of data field 0, pilot sequence 3, and data field 1. Among them, data field 0 has 384 chips, pilot sequence 3 has 128 chips, and data field 1 has 384 chips.

2. A K-band aviation cluster collaborative detection low-latency transmission device as claimed in claim 1, characterized in that: The passive detection system includes three communication nodes, each of which is equipped with two directional antennas to generate two independent transceiver channels. A dedicated channel is established for uplink and downlink communications between all communication nodes through space division + frequency division, and low-latency task information is sent immediately after being prepared.

3. A K-band aviation cluster collaborative detection low-latency transmission device as claimed in claim 1, characterized in that: The processing delay of the passive detection system data is no more than 353 μs.

4. A method for transmitting and receiving low-latency signals based on the device according to claim 1, characterized in that: It includes a data receiving process and a data sending process, wherein the data receiving process includes Step 1: Use the directional antenna to receive the K-band RF signal from the RF transmitting module and transmit it, and at the same time receive the K-band RF signal sent by other nodes and output it to the RF receiving module; Step 2: Use co-site filters to isolate signal transmission and reception; Step 3: Use the RF receiving module to receive the RF signal from the directional antenna, and convert it into an intermediate frequency analog signal output through mixing, filtering, and amplification; Step 4: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the baseband processing module for signal demodulation and timing error estimation; Step 5: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and transmit it synchronously to the link processing module after processing; Step 6: Use the link processing module to perform link layer processing of the task information, and send the task information to the cooperative passive detection information processing module after processing; Step 7: Use the cooperative passive detection information processing module to process the passive detection task information and transmit the local node information to the cooperative node.

5. A method for transmitting and receiving a low-latency signal as claimed in claim 4, characterized in that: The data sending process includes: Step 1: After the cooperative passive detection information processing module processes the passive detection task information, it sends it to the link processing module; Step 2: Use the link processing module to perform link layer processing of the task information, and send the task information to the baseband processing module after processing; Step 3: Use the baseband processing module to perform signal demodulation and timing error estimation on the digital signal, and synchronously transmit it to the analog-to-digital conversion module after processing; Step 5: Use the analog-to-digital conversion module to receive the intermediate frequency analog signal of the RF receiving module, and convert it into a digital signal and output it to the RF structure module; Step 6: Use the RF transmitter module to receive the intermediate frequency analog signal from the digital-to-analog conversion module, and convert it into a K-band RF signal output through frequency conversion, filtering, and amplification.

6. A method for transmitting and receiving a low-latency signal as claimed in claim 4, characterized in that: The data receiving process in the baseband processing module includes: When receiving, the signal is down-converted and the receiving channel is in the capture state by default, searching and capturing the signal; When the capture is completed, the bit synchronization and frequency deviation data are extracted from the frame header, and then the carrier synchronization and timing synchronization of the signal are performed. After the synchronization is completed, the BPSK signal is demodulated. The demodulation adopts the method of extracting soft information and quantizing 8 bits. The data is input to the LDPC decoding module. The LDPC decoding adopts a parallel quantization layered simplified decoding algorithm with offset, and the number of decoding iterations is set to 6.

7. A method for transmitting and receiving low-latency signals as claimed in claim 5, characterized in that: The data transmission process in the baseband processing module includes: When sending, when the task data packet is received, the data sending process is started, and the frame header and source data are processed in parallel. The frame header performs BPSK modulation on the synchronization code, and the source data completes grouping, LDPC coding and BPSK modulation. The LDPC coding uses a segmented coding algorithm to first eliminate the Gaussian elements of the check matrix; Then the matrix P and the information bit S are divided. When storing, each segment of the matrix P is combined into a data and stored in the corresponding memory. When encoding, the segmented data is taken out and the encoding operation is performed with the segmented information bit. Then the frame is formed, and the digital up-conversion is sent to the digital-to-analog conversion module and transmitted through the transmission channel.

8. A method for transmitting and receiving a low-latency signal as claimed in claim 4 or 5, characterized in that: The process of link layer processing of task information by the link processing module includes: In low-latency mode, the link processing module only detects the channel selection bit and directly sends the user data to the corresponding channel for processing based on the channel selection; The working clock is 256MHz. Channel selection decision requires 2 clocks, data transparent transmission requires 2 clocks, and a total of 4 processing clocks are required.

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