CN204967832U - Jointly disturb system based on frequency spectrum perception and modulation recognition - Google Patents

Abstract

The utility model discloses a joint interference system based on spectrum perception and modulation identification, which mainly consists of a control center, a radio frequency receiving module connected to the control center, a dual-channel analog-to-digital conversion module, a first baseband signal processing module, and a second baseband signal processing module. It consists of a processing module and at least one jammer. Combining cognitive radio spectrum sensing with modulation identification and applying it to interference communication, it not only implements perception interference for the establishment of the external link, but also implements communication interference for the communication link that the external party has established. Our cognitive communication system transmits link information, thus realizing an effective anti-jamming strategy for our side.

Description

Joint Jamming System Based on Spectrum Sensing and Modulation Recognition

technical field

The utility model relates to the technical field of communication, in particular to a combined interference system based on spectrum sensing and modulation identification.

Background technique

With the development of wireless communication technology, the number of wireless communication devices is increasing day by day, and the requirements for data transmission rate are also getting higher and higher, and the wireless communication rate can even reach hundreds of megabytes per second. However, the spectrum resources that people can use are limited, and they are also facing the problem of scarcity of spectrum resources while making breakthroughs in wireless communication technology. In many licensed frequency bands, most of the time is idle, that is, there are many "spectrum holes". How to use these "spectrum holes" has become a hot research issue today. As a more intelligent spectrum detection and sharing technology, cognitive radio technology can detect the surrounding electromagnetic environment and make full use of the idle frequency bands of authorized users without interfering with authorized users, thereby improving spectrum utilization. Modulation recognition technology is a key technology in non-cooperative communication, and it is widely used in spectrum management, spectrum monitoring, communication fault detection and military communication in civil communication. Through the modulation recognition technology, air signals can be intercepted, so as to conduct parameter analysis and provide important information for subsequent tasks such as threat identification, information cracking, and interference identification.

In military communication, using cognitive radio intelligent spectrum detection and switching technology, spectrum resources can be quickly occupied and switched, and modulation identification technology can be used to intercept information on the link that has been communicated, so as to implement interference or information demodulation . At present, it is popular to send interference signals to idle frequency bands to achieve the purpose of sensing interference. However, this method can only interfere with cognitive users who have not established a link, and cannot effectively interfere with users who have established a link, and after interference, it will also affect our cognitive communication system, making our cognitive communication system also does not work. The modulation recognition technology can only implement communication interference to communication users who have established a link, but cannot interfere with the link formation of the cognitive communication system.

Utility model content

The utility model aims to solve the problem that the existing method of sending interference signals to idle frequency bands cannot effectively interfere with established link users, and the way of modulation identification cannot interfere with the formation of links of cognitive communication systems. A joint jamming system based on spectrum sensing and modulation recognition.

In order to solve the above problems, the utility model is achieved through the following technical solutions:

The joint interference system based on spectrum sensing and modulation identification mainly consists of a control center, a radio frequency receiving module connected to the control center, a dual-channel analog-to-digital conversion module, a first baseband signal processing module, a second baseband signal processing module and at least one The jammer is composed of; wherein the number h of the jammer is related to the number of sub-bands g subdivided into the whole frequency band during spectrum sensing, that is, h=g-1; the data output end of the radio frequency receiving module is connected to the first through the dual-channel analog-to-digital conversion module The input terminals of the baseband signal processing modules are connected; the output terminals of the first baseband signal processing module are connected with the input terminals of the second baseband signal processing module; the output terminals of the second baseband signal processing module are connected with the input terminals of each jammer.

In the above scheme, the radio frequency receiving module is composed of radio frequency receiving antenna, bandpass filter, radio frequency low noise amplifier, radio frequency DDS, mixer, radio frequency I road low pass filter, radio frequency Q road low pass filter, radio frequency I road automatic gain Composed of a control amplifier and a radio frequency Q-channel automatic gain control amplifier; the radio frequency receiving antenna is connected to a radio frequency low noise amplifier through a bandpass filter, and the output terminal of the radio frequency low noise amplifier is connected to an input terminal of the mixer; the input terminal of the radio frequency DDS is connected to the control In the center, the output end of the radio frequency DDS is connected with the other input end of the mixer; the output end of the mixer is divided into I and Q two roads, and the output end of the I road is connected to the radio frequency I road automatic through a low pass filter of the radio frequency I road. The input end of the gain control amplifier, the output end of the Q path is connected to the input end of the radio frequency Q path automatic gain control amplifier through the radio frequency Q path low-pass filter; the output of the output end of the radio frequency I path automatic gain control amplifier and the radio frequency Q path automatic gain control amplifier The terminal is simultaneously connected to the input terminal of the dual-channel analog-to-digital conversion module.

In the above scheme, the jammer consists of jamming FPGA, jamming I channel DAC, jamming Q channel DAC, jamming I channel low pass filter, jamming Q channel low pass filter, quadrature modulator, jamming DDS, Composed of a power amplifier, an interference low-pass filter and a radio frequency transmitting antenna; the input end of the interference FPGA is connected to the second baseband processing module, and the output end of the interference FPGA is divided into I and Q two roads, wherein the output end of the I road is passed through the interference I road digital-analog The converter is connected to the input end of the interference I-way low-pass filter, wherein the output end of the Q-way is connected to the input end of the interference Q-way low-pass filter through the interference Q-way digital-to-analog converter; the interference I-way low-pass filter and the interference Q-way The output end of the low-pass filter is connected to an input end of the quadrature modulator at the same time, the input end of the interference DDS is connected to the control center, and the output end of the interference DDS is connected to the other input end of the quadrature modulator; The output end is connected to the input end of the power amplifier through the interference low-pass filter, and the output end of the interference low-pass filter is connected to the radio frequency transmitting antenna.

The above joint interference system further includes a host computer, which is connected to the first baseband processing module and the second baseband processing module.

Compared with the existing technology, the utility model combines cognitive radio spectrum sensing and modulation identification, and applies it to interference communication, which not only implements the perception interference for the establishment of the external link, but also implements the interference for the communication link that the external party has established. Implement communication jamming, and at the same time of jamming, it also transmits link information for our cognitive communication system, thus realizing an effective anti-jamming strategy for our side. Among them, the spectrum sensing method operated inside the first baseband signal processing module, the signal feature extraction and modulation mode identification method operated inside the second baseband signal processing module, and the interference signal generation method operated inside the jammer are all known in the prior art. Using method, the key point of the utility model is to combine the three organically, to realize effective interference to the outside party.

Description of drawings

Fig. 1 is a system block diagram of a joint jamming system based on spectrum sensing and modulation identification.

Fig. 2 is a specific block diagram of the first baseband signal processing module and the second baseband signal processing module.

Figure 3 is a block diagram of the radio frequency receiving module.

Figure 4 is a block diagram of the jammer structure.

detailed description

The joint interference system based on spectrum sensing and modulation identification designed based on the above method, as shown in Figure 1, mainly consists of a radio frequency receiving module, a dual-channel analog-to-digital conversion module, a first baseband signal processing module, a second baseband signal processing module, It consists of a control center, a host computer and at least one jammer. The number h of jammers is related to the number of sub-bands g in which the whole frequency band is subdivided during spectrum sensing, that is, h=g-1. In the preferred embodiment of the present invention, since the whole frequency band is subdivided into 9 sub-frequency bands, there are 8 jammers. The data output end of the radio frequency receiving module is connected with the first baseband signal processing module through a dual-channel analog-to-digital conversion module. The first baseband signal processing module is connected to the second baseband signal processing module. The eight jammers are connected in parallel to a bus, and the bus is connected to the second baseband signal processing module. The control center is respectively connected with the radio frequency receiving module, the dual-channel analog-to-digital conversion module, the first baseband signal processing module, the second baseband signal processing module and 8 jammers. The host computer is connected with the first baseband processing module and the second baseband processing module.

The control center uses ARM as the main control chip, which is responsible for receiving and sending commands to control the operation of the entire system. The upper computer is a PC, responsible for the display of signal processing results. The first baseband signal processing module uses FPGA as the processor, and is mainly responsible for spectrum sensing and communication with the host computer. The second baseband signal processing module uses DSP as the processor, and is responsible for identifying the signal modulation mode and communicating with the host computer. When the spectrum sensing device is used in combination with the modulation identification device, it can interfere with the establishment of the communication link of the foreign cognitive user and the communication of the foreign main user. The combination of FPGA and DSP, relying on the powerful parallel processing capability of FPGA and the high-performance data processing capability of DSP, not only ensures the accuracy of complex signal processing, but also shortens the running time of the program, and at the same time greatly reduces the development cycle. For a specific block diagram of the first baseband signal processing module and the second baseband signal processing module, refer to FIG. 2 .

The RF receiving module adopts a zero-IF receiver, as shown in Figure 3, mainly composed of an RF receiving antenna, a band-pass filter, a RF low-noise amplifier, a RF DDS, a mixer, a RF I low-pass filter, and a RF Q low-pass filter. It is composed of a pass filter, a radio frequency I-channel automatic gain control amplifier and a radio frequency Q-channel automatic gain control amplifier. The radio frequency receiving antenna is connected with the radio frequency low noise amplifier through the band pass filter, and the output terminal of the radio frequency low noise amplifier is connected with an input terminal of the mixer. The input end of the radio frequency DDS is connected to the control center, and the output end of the radio frequency DDS is connected to the other input end of the mixer. The output terminal of the mixer is divided into I and Q two channels, wherein the output terminal of the I channel is connected to the input terminal of the automatic gain control amplifier of the radio frequency I channel through the radio frequency I channel low-pass filter, and the Q channel output terminal is filtered by the radio frequency Q channel low pass filter The device is connected to the input terminal of the RF Q-channel automatic gain control amplifier. The output terminals of the radio frequency I-channel automatic gain control amplifier and the radio frequency Q-channel automatic gain control amplifier are simultaneously connected to the input terminals of the dual-channel analog-to-digital conversion module. The radio frequency signal is received by the radio frequency receiving antenna, after passing through the band-pass filter with a bandwidth of 3-30M, after being linearly amplified by the low-noise amplifier, it enters an input terminal of the mixer. The other input end of the mixer is connected to the output end of the DDS controlled by the control center. The output of the mixer is divided into I and Q two channels. After being filtered by a 1.5M low-pass filter, the outputs of I and Q channels respectively enter the automatic gain control amplifier. After the stable gain, the two channels of I and Q The signal enters a dual-channel analog-to-digital conversion module for analog-to-digital conversion, and then enters the first baseband signal processing module for information processing. In the preferred embodiment of the utility model, the low noise amplifier adopts MWLA-000050M20, the working range is 100K-50Mhz, and it can cover the whole frequency band of 3-30M. DDS adopts AD9834, the output frequency is up to 37.5M, and the required frequency can be switched freely by sending the register control word to AD9834 through the control center processor. The mixer adopts RF2713, and its operating frequency range is 100K ~ 250M, which can be directly down-converted to divide the signal into I and Q and move it to the baseband. The receiver adopts a zero-IF structure and uses DDS as the frequency output module. The control center only needs to change the DDS output frequency to mix different frequency points to the baseband. Compared with the secondary frequency conversion structure, it is simpler and effectively suppresses image frequency interference.

The jammer is responsible for the generation and transmission of pseudo-random noise sequences and modulated signals such as ASK, 2ASK, FSK, 2FSK, PSK, 2PSK, QAM, etc., as shown in Figure 4. It consists of a digital-to-analog converter, an interference I low-pass filter, an interference Q low-pass filter, a quadrature modulator, an interference DDS, a power amplifier, an interference low-pass filter and a radio frequency transmitting antenna. The input end of interference FPGA is connected with the second baseband processing module, and the output end of interference FPGA is divided into two roads of I and Q, wherein the output end of I road is connected with the input end of interference I road low-pass filter through interference I road digital-to-analog converter, Wherein, the Q-channel output terminal is connected to the input terminal of the disturbance Q-channel low-pass filter through the interference Q-channel digital-to-analog converter. The output terminals of the interference I-channel low-pass filter and the interference Q-channel low-pass filter are simultaneously connected to an input terminal of the quadrature modulator, the input terminal of the disturbance DDS is connected to the control center, and the output terminal of the disturbance DDS is connected to the quadrature modulator the other input terminal. The output end of the quadrature modulator is connected to the input end of the power amplifier through the interference low-pass filter, and the output end of the interference low-pass filter is connected to the radio frequency transmitting antenna. The FPGA has two built-in signal generation modules, a pseudo-random noise sequence generation module, and a digital baseband signal generation module. At the same time, the FPGA is also connected to the second baseband signal processing module, which is responsible for the transmission of signal characteristic parameters. When the FPGA receives the corresponding instruction, the corresponding signal generation module works. If the FPGA receives the instruction 0000, the jammer No. 000 will send a pseudo-random noise signal to the detection frequency band at this time. When the FPGA receives the instruction 0001, the jammer No. 000 will send the similar signal detected by the second baseband signal processing module to this frequency band Modulated signal. The baseband signal generated by the FPGA is divided into I and Q channels. The I and Q channels are converted into analog signals through the DA respectively, and then sent to the I and Q channels of the quadrature modulator after passing through the low-pass filter respectively. The other end of the quadrature modulator is connected to the output end of the DDS controlled by the control center. The DDS generates the center frequency of the detection frequency band at this time and inputs it to the quadrature modulator. The quadrature modulator moves the baseband signal to the frequency band detected at this time, and after being amplified by the power amplifier and filtered by the low-pass filter, it is transmitted into the air through the radio frequency transmitting antenna to complete the transmission of the interference signal. The jamming signal transmitted by the jammer on all idle frequency bands is a pseudo-random noise signal, which can be recognized by our cognitive users, that is, the jammer can also be used as a cognitive communication transmitter to send frequency band usage information to our cognitive users . Each jammer has its own DDS module and a corresponding code number, which can interfere with the whole frequency band and switch the interference frequency band at will, so that the jamming can become accurate and flexible.

The system can scan and monitor the electromagnetic environment in real time within the specified frequency band, and accurately detect idle frequency bands and occupied frequency bands in real time. For idle frequency bands, it sends our pseudo-random noise signals to quickly occupy the idle frequency band, and can be allocated to our side at any time. Cognitive users, for the busy frequency band, through signal modulation identification, analyze the signal characteristics and modulation method, so as to judge whether it is an enemy signal, if it is an enemy signal, carry out waveform design according to the signal characteristics and modulation method, send and The waveform signal similar to the other side, so as to achieve the purpose of interfering with the enemy's communication in all directions.

Claims (4)

1. The joint jamming system based on spectrum sensing and modulation identification is characterized in that it mainly consists of a control center, a radio frequency receiving module connected to the control center, a dual-channel analog-to-digital conversion module, a first baseband signal processing module, and a second baseband signal processing module. The processing module is composed of at least one jammer; wherein the number h of the jammer is related to the number of sub-bands g subdivided into the whole frequency band during spectrum sensing, that is, h=g-1; The digital conversion module is connected to the input end of the first baseband signal processing module; the output end of the first baseband signal processing module is connected to the input end of the second baseband signal processing module; the output end of the second baseband signal processing module is connected to each jammer connected to the input. 2. The joint interference system based on spectrum sensing and modulation identification according to claim 1, wherein the radio frequency receiving module is composed of radio frequency receiving antenna, bandpass filter, radio frequency low noise amplifier, radio frequency DDS, mixer, radio frequency I low-pass filter, RF Q low-pass filter, RF I-channel automatic gain control amplifier and RF Q-channel automatic gain control amplifier; the RF receiving antenna is connected to the RF low-noise amplifier through the band-pass filter, and the RF low-noise amplifier The output terminal of the RF DDS is connected to one input terminal of the mixer; the input terminal of the RF DDS is connected to the control center, and the output terminal of the RF DDS is connected to the other input terminal of the mixer; the output terminal of the mixer is divided into I and Q two Road, wherein the I-way output end is connected to the input end of the radio frequency I-way automatic gain control amplifier through the radio frequency I-way low-pass filter, and the Q-way output end is connected to the input end of the radio frequency Q-way automatic gain control amplifier through the radio frequency Q-way low-pass filter ; The output terminals of the radio frequency I-channel automatic gain control amplifier and the radio frequency Q-channel automatic gain control amplifier are simultaneously connected to the input terminals of the dual-channel analog-to-digital conversion module. 3. The joint interference system based on spectrum sensing and modulation identification according to claim 1, characterized in that, The jammer consists of jamming FPGA, jamming I channel DAC, jamming Q channel DAC, jamming I channel low pass filter, jamming Q channel low pass filter, quadrature modulator, jamming DDS, power amplifier, jamming Composed of a low-pass filter and a radio frequency transmitting antenna; the input end of the interference FPGA is connected to the second baseband processing module, and the output end of the interference FPGA is divided into I and Q two roads, wherein the output end of the I road is connected to the interference by the interference I road digital-to-analog converter The input end of the I-way low-pass filter, wherein the Q-way output terminal is connected to the input end of the interference Q-way low-pass filter through the interference Q-way digital-to-analog converter; the interference I-way low-pass filter and the interference Q-way low-pass filter The output end of the interference DDS is connected to an input end of the quadrature modulator at the same time, the input end of the interference DDS is connected to the control center, and the output end of the interference DDS is connected to the other input end of the quadrature modulator; the output end of the quadrature modulator is disturbed The low-pass filter is connected to the input end of the power amplifier, and the output end of the interference low-pass filter is connected to the radio frequency transmitting antenna. 4. The joint interference system based on spectrum sensing and modulation identification according to claim 1, further comprising a host computer connected to the first baseband processing module and the second baseband processing module.