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CN-116886235-B - LTE downlink signal forwarding type interference system

CN116886235BCN 116886235 BCN116886235 BCN 116886235BCN-116886235-B

Abstract

The invention discloses an LTE downlink signal forwarding type interference system which comprises a receiving antenna, a transmitting antenna group, a sweep frequency processing module, a radio frequency processing and method module and a signal processing module, wherein the signal processing module comprises an FPGA processing unit, an ADC processing unit, a DSP processing unit, a DRFM unit and a DAC processing unit. The interference system of the invention can dynamically collect and store the interference waveform information by detecting and forwarding the base station downlink signal of the partial frequency division point only in the specific time slot, thereby greatly reducing the frequency spectrum resource requirement required by interference, and can timely adjust the time strategy and the forwarding time slot according to the change of the base station signal by the allocation processing strategy of real-time detection and interference, thereby adapting to the differential detection interference in different areas.

Inventors

  • DONG HAO
  • JIA SHAN
  • YUAN JINWEI
  • TIAN LANG
  • CHEN SIHONG

Assignees

  • 四川九洲电器集团有限责任公司

Dates

Publication Date
20260512
Application Date
20230811

Claims (10)

  1. 1. The LTE downlink signal forwarding type interference system is characterized by comprising a receiving antenna, a transmitting antenna group, a sweep frequency processing module, a radio frequency processing and method module and a signal processing module, wherein the signal processing module comprises an FPGA processing unit, an ADC processing unit, a DSP processing unit, a DRFM unit and a DAC processing unit; The FPGA processing unit generates a control signal to complete connection of the receiving antenna and the sweep frequency processing module; the sweep frequency processing module down-converts the received signals of different frequency bands to the same intermediate frequency signal IF1 according to the time interval of each frequency band lasting T1 and sends the signals to the ADC processing unit; the ADC processing unit digitizes the collected intermediate frequency signal IF1, converts the intermediate frequency signal IF1 into an IQ1 signal and sends the IQ1 signal to the FPGA processing unit; The FPGA processing unit extracts and digital DDC and narrow-band filters the IQ1 signals, detects the PSS signals through a correlation peak detection algorithm, detects and decodes the SSS signals of the data segments where the PSS signals are found, acquires source configuration information Dt1, and sends the source configuration information Dt1 to the DSP for algorithm processing; The DSP processing unit constructs a two-dimensional matrix R1 of carrier wave about frequency block and time block resource allocation based on source allocation information Dt1, constructs a three-dimensional matrix R2 of each carrier wave frequency band about special sub-frame in time, frequency and time attribute through a plurality of detection processes of the frequency band information, constructs a narrow-band digital filter group L1 by utilizing the three-dimensional matrix R2, filters sub-carriers of all non-special sub-frames, searches downlink frequency information of each frequency band in sequence according to the process, acquires a three-dimensional resource allocation matrix Rn under all carrier waves, and constructs a narrow-band digital filter group Ln corresponding to the carrier wave; the signal data input by the sweep frequency processing module is directly sent to the narrow-band digital filter bank Ln for processing after being digitized and filtered by the ADC processing unit and the FPGA processing unit, and the processed data is sent to the DRFM unit for storage after being classified and marked by the FPGA processing unit; When forwarding interference is carried out, the FPGA processing unit timely calls different waveform files stored in the DRFM unit based on time and frequency requirement information, and baseband forwarding interference signals with different carrier frequencies are respectively generated through the DAC and sent to the radio frequency processing and amplifying module; And after the radio frequency processing and amplifying module processes the received signals, the target interference is realized through the transmitting antenna group.
  2. 2. The LTE downlink signal forwarding type interference system of claim 1 wherein the method for constructing the three-dimensional matrix R2 specifically comprises the steps that after the DSP processing unit completes air interface information analysis of each frequency band based on the source configuration information Dt1, frequency and time information of a DwPTS, GP, upPTS, PSS, SSS resource block is obtained, and a three-dimensional matrix related to frequency, time and time attributes is constructed.
  3. 3. The LTE downlink signal forwarding type interference system of claim 1 wherein the FPGA unit comprises an FPGA1 chip and an FPGA2 chip.
  4. 4. The LTE downlink signal forwarding type interference system of claim 3, wherein the signal processing module is divided into a scout signal processing board and an interference signal processing board, The ADC processing unit, the DSP processing unit and the FPGA1 chip are integrated on the investigation signal processing board; the FPGA2 chip, the DRFM unit and the DAC processing unit are integrated on the interference signal processing board.
  5. 5. The LTE downlink signal forwarding type interference system of claim 3 or 4, wherein the IQ1 signal is sent to an FPGA1 chip in the FPGA processing unit, the FPGA1 chip extracts the IQ1 signal, performs digital DDC and narrowband filtering, detects the PSS signal by a correlation peak detection algorithm, performs SSS signal detection and CP decoding on the data segment where the PSS signal is found, obtains source configuration information Dt1, and sends the source configuration information Dt1 to the DSP for algorithmic processing.
  6. 6. The LTE downlink signal forwarding type interference system of claim 3 or 4 wherein the FPGA1 chip in the FPGA processing unit sends the baseband IQ data IQ2 processed by the narrowband digital filter bank Ln to the FPGA2 chip, the FPGA2 chip classifies and marks the baseband IQ data IQ2 to obtain data IQ3, and sends the corresponding processed data IQ3 to the DRFM unit for storage.
  7. 7. The LTE downlink signal forwarding interference system of claim 5 wherein, when forwarding interference, the FPGA1 chip generates a timeslot control signal of multiband forwarding interference based on a result of collecting and analyzing IQ1 signals, and transmits corresponding frequency and time information to the FPGA2 chip through the SPI port; And the PGA2 chip timely calls different waveform files stored in the DRFM unit according to the time and frequency requirement information provided by the FPGA1 chip.
  8. 8. The LTE downlink signal forwarding type interference system of claim 7 wherein the transmission time slot and the closing time slot in the time slot control signal are obtained based on PSS detection results; The first 5 symbol bits of each frame of the downlink signal transmission of the base station open the transmission time slot, and after each frame is finished, the 5 symbol bits open the closing time slot.
  9. 9. The LTE downlink signal forwarding type interference system of claim 1 further comprising a switch, wherein the switch is a single pole double throw radio frequency switch, wherein the fixed end is connected to the transceiver antenna, When the interference is executed, the switch disconnects the RF2 from the sweep frequency processing module; the switching signal IO1 of the switching switch is given by an IO port of an FPGA1 chip in the FPGA processing unit.
  10. 10. The LTE downlink signal forwarding type interference system of claim 1 wherein the receiving antenna is an omni-directional antenna, the transmitting antenna group is an omni-directional antenna or a directional antenna, and the operating frequencies of the receiving antenna and the transmitting antenna group cover an operating frequency band of LTE.

Description

LTE downlink signal forwarding type interference system Technical Field The invention belongs to the technical field of communication signal interference, and particularly relates to an LTE downlink signal forwarding type interference system. Background The LTE downlink signal forwarding type interference technology is mainly a technology for forwarding type interference of 4G LTE downlink signals. The LTE comprises TD-LTE and LTE FDD, wherein the LTE adopts an uplink and downlink frequency division mode for communication, and the TD-LTE adopts an uplink and downlink same frequency division mode for communication. The forwarding interference has a mature technical architecture at present and is often applied to the technical fields of radar interference and the like. In contrast, in the field of mobile communication countermeasure, since a mobile communication signal is long in space and a communication frequency is relatively fixed, interference is rarely implemented using a repeater type interference. The prior knowledge reconnaissance is generally adopted to acquire the mobile communication spectrum distribution, and the DDS mode is adopted to directly generate the repetitively scanned broadband interference signal to implement interference on the signal. The traditional interference mode has good effect on interference to signals such as GSM, WCDMA and the like, but with the release of LTE communication modes, the suppression interference mode which looks like frequency coverage cannot achieve good interference effect. Because the LTE adopts OFDM modulation, the useful resource blocks are unevenly distributed in the broadband signal of 20MHz and uplink and downlink strategies can be allocated and scheduled according to different time slots, so that most of power and time of broadband sweep frequency interference are wasted on useless frequency points, and meanwhile, the unique carrier fusion processing technology of the LTE improves the scheduling breadth of communication frequency resources, so that the interference capability of the broadband sweep frequency interference technology based on power suppression is greatly reduced on an LTE system. The existing interference methods for the LTE mobile phone comprise broadband suppression interference, pilot suppression interference and the like. The broadband interference suppression method is used for covering the full frequency band and the full time period of the LTE system, has low interference efficiency and has a large amount of energy waste. The pilot frequency suppresses the interference mode, through the mode that pilot frequency was reconnaissad, reconnaissance algorithm is simple, the technical difficulty is little. The method can achieve a certain effect on pilot frequency suppression interference, but the LTE base station usually adopts a non-fixed pilot frequency architecture, the interference mode can only achieve the effect on partial frequency points, the general applicability of space cannot be met, and the application range is narrow. Disclosure of Invention In order to overcome the problems in the prior art, the invention discloses an LTE downlink signal forwarding type interference system, wherein the interference system only needs to generate a base station downlink signal of a frequency division point of a forwarding part in a specific time slot by a reconnaissance forwarding mode, thereby greatly reducing the spectrum resource requirement required by interference; and through the allocation processing strategy of real-time reconnaissance and interference, the interference waveform information is dynamically acquired and stored, and the time strategy and the forwarding time slot can be timely adjusted according to the change of the base station signal, so that the method is suitable for differential reconnaissance interference in different areas. The aim of the invention is achieved by the following technical scheme: The LTE downlink signal forwarding type interference system comprises a receiving antenna, a transmitting antenna group, a sweep frequency processing module, a radio frequency processing and method module and a signal processing module, wherein the signal processing module comprises an FPGA processing unit, an ADC processing unit, a DSP processing unit, a DRFM unit and a DAC processing unit; The FPGA processing unit generates a control signal to complete connection of the receiving antenna and the sweep frequency processing module; the sweep frequency processing module down-converts the received signals of different frequency bands to the same intermediate frequency signal IF1 according to the time interval of each frequency band lasting T1 and sends the signals to the ADC processing unit; the ADC processing unit digitizes the collected intermediate frequency signal IF1, converts the intermediate frequency signal IF1 into an IQ1 signal and sends the IQ1 signal to the FPGA processing unit; The FPGA processing unit extract