Method and system for detecting unauthorized frequency band wifi device

Abstract

The invention discloses a method and system for detecting wifi equipment in an unauthorized frequency band. The method comprises the following steps: capturing IQ data in the unauthorized frequency band based on SDR equipment; determining a corresponding baseband signal according to the demodulation of the IQ data in the unlicensed frequency band; defining decoded data based on signal processing of the baseband signal; defining a wifi data frame according to the decoded data and a frame format of a Wi-Fi protocol; the parameters of the unauthorized frequency band wifi device are determined based on the wifi data frame, so that the real-time detection of the parameters of the unauthorized frequency band wifi device is realized, the real-time detection of the unauthorized frequency band wifi device is realized, the IQ data in the unauthorized frequency band is comprehensively covered, the detection accuracy of the unauthorized frequency band wifi device is ensured, and in addition, the detection accuracy of the unauthorized frequency band wifi device is improved. According to the embodiment of the invention, the parameters and the wifi data frame of the unauthorized frequency band wifi device are stored, so that evidence obtaining is carried out on the unauthorized frequency band wifi device and the wifi data frame, and the unauthorized frequency band wifi device is controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of detection systems for unlicensed frequency band Wi-Fi devices, and in particular to a detection method and system for unlicensed frequency band Wi-Fi devices. Background Art

[0002] With the development of science and technology, data security has received more and more attention. Stealing devices steal data based on informal means. At this time, when the stealing devices use unconventional wireless networks to perform data stealing operations, because the stealing devices working in unauthorized frequency bands will be hidden, it is necessary to control the stealing devices in unauthorized frequency bands, but the existing technology does not control the unauthorized frequency band wifi devices. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art. The present invention provides a detection method and system for unlicensed frequency band wifi devices, which capture IQ data in the unlicensed frequency band based on an SDR device; determine the corresponding baseband signal based on demodulation of the IQ data in the unlicensed frequency band; define decoded data based on signal processing of the baseband signal; define a wifi data frame based on the decoded data and the frame format of the Wi-Fi protocol; determine the parameters of the unlicensed frequency band wifi device based on the wifi data frame to achieve real-time detection of the parameters of the unlicensed frequency band wifi device, thereby performing real-time detection on the unlicensed frequency band wifi device, and comprehensively covering the IQ data in the unlicensed frequency band, so as to ensure the detection accuracy of the unlicensed frequency band wifi device, and in addition, save the parameters and wifi data frames of the unlicensed frequency band wifi device, so as to collect evidence for the unlicensed frequency band wifi device and the wifi data frame, so as to control the unlicensed frequency band wifi device.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides a detection method for unlicensed frequency band WiFi devices, which is applied to the detection scenario of unlicensed frequency band WiFi devices;

[0005] The detection method of the unlicensed frequency band WiFi device comprises:

[0006] Capture IQ data in unlicensed frequency bands based on SDR equipment;

[0007] Determining a corresponding baseband signal based on demodulation of IQ data in the unlicensed frequency band;

[0008] defining decoded data based on signal processing of the baseband signal;

[0009] Define the Wi-Fi data frame based on the decoded data and the frame format of the Wi-Fi protocol;

[0010] Determine the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device;

[0011] The parameters and WiFi data frames of unlicensed frequency band WiFi devices are saved.

[0012] Optionally, the capturing of IQ data in an unlicensed frequency band based on an SDR device includes:

[0013] Locate SDR equipment;

[0014] The SDR device captures the spectrum signal at the RF front end;

[0015] A digital IQ data stream is formed based on analog-to-digital conversion of the spectrum signal;

[0016] Correlate digitized IQ data streams and unlicensed spectrum;

[0017] The IQ data in the unlicensed band is defined based on the digitized IQ data stream and the unlicensed band.

[0018] Optionally, the determining a corresponding baseband signal according to demodulation of IQ data in the unlicensed frequency band includes:

[0019] Freeze the IQ data in the unlicensed frequency band and store the IQ data in the unlicensed frequency band;

[0020] Performing orthogonal demodulation on the IQ data in the unlicensed frequency band and outputting multiple signals;

[0021] A corresponding baseband signal is determined based on the plurality of signals.

[0022] Optionally, the determining a corresponding baseband signal according to demodulation of IQ data in the unlicensed frequency band further includes:

[0023] The IQ data in the unlicensed frequency band is orthogonally demodulated. At this time, the formula of the orthogonal demodulation algorithm is as follows:

[0024] y(t)=xI(t)cos(2πfct)-xQ(t)sin(2πfct),

[0025] Where y(t) is the baseband signal, xI(t) and xQ(t) are the real and imaginary parts of the IQ data, respectively, and fct is the carrier frequency.

[0026] Optionally, the defining decoded data based on signal processing of the baseband signal includes:

[0027] Freeze baseband signal;

[0028] Determine the boundary of the data symbol based on the baseband signal and the symbol synchronization algorithm, and align the data according to the boundary of the data symbol;

[0029] Correlate baseband signals and decoding algorithms;

[0030] Defining decoded data based on signal processing of the baseband signal and the decoding algorithm;

[0031] Among them, for aligning data according to the boundary of data symbols, a related algorithm is used, and the formula of the related algorithm is as follows:

[0032]

[0033] where ρk is the cross-correlation coefficient at time offset k and rn is the received signal sample.

[0034] Optionally, defining a Wi-Fi data frame according to the decoded data and a frame format of a Wi-Fi protocol includes:

[0035] Freeze the decoded data;

[0036] Associate the decoded data with the frame format of the Wi-Fi protocol;

[0037] Depacketize the decoded data according to the frame format of the Wi-Fi protocol and output multiple key parameters;

[0038] Define wifi data frames based on multiple key parameters;

[0039] The decoded data is unpacked according to the frame format of the Wi-Fi protocol, using the Viterbi algorithm, the formula of which is as follows:

[0040] Si,t+1=minj{Sj,t+cost(sj→si)},

[0041] where Si,t is the cumulative cost of state i at time t, and cost(sj→si) is the branch cost from state j to state i.

[0042] Optionally, determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device includes:

[0043] Freeze wifi data frame;

[0044] Associate wifi data frames and unlicensed frequency bands.

[0045] Optionally, the determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device further includes:

[0046] Determine the parameters of the unlicensed frequency band WiFi device according to the WiFi data frame and the unlicensed frequency band;

[0047] Based on the real-time response of the parameters of the unlicensed frequency band WiFi device, the real-time detection of the parameters of the unlicensed frequency band WiFi device is achieved.

[0048] Optionally, the storing of parameters and WiFi data frames of unlicensed frequency band WiFi devices includes:

[0049] Freeze the parameters and WiFi data frames of unlicensed frequency band WiFi devices;

[0050] Input the parameters and WiFi data frames of the unlicensed frequency band WiFi device into the storage space;

[0051] The parameters and WiFi data frames of unlicensed frequency band WiFi devices are triggered based on the storage space, and the parameters and WiFi data frames of unlicensed frequency band WiFi devices are saved separately. At the same time, the real-time supplement and evidence collection of the storage space are triggered.

[0052] In addition, an embodiment of the present invention further provides a detection system for unlicensed frequency band WiFi devices, and the detection system for unlicensed frequency band WiFi devices includes:

[0053] A capture module, used to capture IQ data in unlicensed frequency bands based on SDR equipment;

[0054] A baseband signal module, used to determine a corresponding baseband signal according to the demodulation of the IQ data in the unlicensed frequency band;

[0055] A decoding module, for defining decoded data based on signal processing of the baseband signal;

[0056] The wifi data frame module is used to define the wifi data frame according to the decoded data and the frame format of the Wi-Fi protocol;

[0057] A detection module, used to determine the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame, so as to realize the real-time detection of the parameters of the unlicensed frequency band WiFi device;

[0058] The saving module is used to save the parameters and WiFi data frames of the unlicensed frequency band WiFi device.

[0059] In an embodiment of the present invention, through the method in the embodiment of the present invention, IQ data in an unlicensed frequency band is captured based on an SDR device; a corresponding baseband signal is determined based on demodulation of the IQ data in the unlicensed frequency band; decoded data is defined based on signal processing of the baseband signal; a wifi data frame is defined based on the decoded data and a frame format of the Wi-Fi protocol; parameters of an unlicensed frequency band wifi device are determined based on the wifi data frame to achieve real-time detection of parameters of the unlicensed frequency band wifi device, thereby performing real-time detection on the unlicensed frequency band wifi device, and comprehensively covering the IQ data in the unlicensed frequency band, so as to ensure the detection accuracy of the unlicensed frequency band wifi device, and in addition, the parameters and wifi data frames of the unlicensed frequency band wifi device are saved, so as to collect evidence on the unlicensed frequency band wifi device and the wifi data frame, so as to control the unlicensed frequency band wifi device. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only 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.

[0061] Figure 1 It is a flowchart of a method for detecting unlicensed frequency band WiFi devices in an embodiment of the present invention;

[0062] Figure 2 It is a flow chart of S11 in the detection method of unlicensed frequency band WiFi device in an embodiment of the present invention;

[0063] Figure 3 It is a flow chart of S12 in the method for detecting unlicensed frequency band WiFi devices in an embodiment of the present invention;

[0064] Figure 4 It is a flow chart of S13 in the method for detecting unlicensed frequency band WiFi devices in an embodiment of the present invention;

[0065] Figure 5 It is a flowchart of S14 in the detection method of unlicensed frequency band WiFi device in an embodiment of the present invention;

[0066] Figure 6 It is a flowchart of S15 in the method for detecting unlicensed frequency band WiFi devices in an embodiment of the present invention;

[0067] Figure 7It is a flow chart of S16 in the method for detecting unlicensed frequency band WiFi devices in an embodiment of the present invention;

[0068] Figure 8 It is a schematic diagram of the structure of the detection system of the unlicensed frequency band WiFi device in an embodiment of the present invention;

[0069] Fig. 9 The figure is a hardware diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0071] Method Embodiment

[0072] See also Figures 1 to 9 , a detection method for unlicensed frequency band WiFi devices, applied to the detection scenario of unlicensed frequency band WiFi devices; the detection method for unlicensed frequency band WiFi devices includes:

[0073] Step S11: Capturing IQ data in the unlicensed frequency band based on the SDR device;

[0074] Step S12: Determine a corresponding baseband signal according to demodulation of IQ data in the unlicensed frequency band;

[0075] Step S13: Defining decoded data based on signal processing of the baseband signal;

[0076] Step S14: defining a Wi-Fi data frame according to the decoded data and the frame format of the Wi-Fi protocol;

[0077] Step S15: determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device;

[0078] Step S16: Save the parameters and WiFi data frames of the unlicensed frequency band WiFi device.

[0079] In an embodiment of the present invention, through the method in the embodiment of the present invention, IQ data in an unlicensed frequency band is captured based on an SDR device; a corresponding baseband signal is determined based on demodulation of the IQ data in the unlicensed frequency band; decoded data is defined based on signal processing of the baseband signal; a wifi data frame is defined based on the decoded data and a frame format of the Wi-Fi protocol; parameters of an unlicensed frequency band wifi device are determined based on the wifi data frame to achieve real-time detection of parameters of the unlicensed frequency band wifi device, thereby performing real-time detection on the unlicensed frequency band wifi device, and comprehensively covering the IQ data in the unlicensed frequency band, so as to ensure the detection accuracy of the unlicensed frequency band wifi device, and in addition, the parameters and wifi data frames of the unlicensed frequency band wifi device are saved, so as to collect evidence on the unlicensed frequency band wifi device and the wifi data frame, so as to control the unlicensed frequency band wifi device.

[0080] refer to Figure 2 , in step S11, capturing IQ data in an unlicensed frequency band based on an SDR device;

[0081] In the specific implementation process of the present invention, the specific steps may be:

[0082] S111: Positioning SDR equipment;

[0083] S112: The SDR device captures the spectrum signal at the RF front end;

[0084] S113: forming a digital IQ data stream based on analog-to-digital conversion of the spectrum signal;

[0085] S114: Associating digitized IQ data streams and unlicensed frequency bands;

[0086] S115: Define IQ data in the unlicensed frequency band based on the digitized IQ data stream and the unlicensed frequency band.

[0087] In an embodiment of the present application, an SDR device is positioned and introduced. The SDR device serves as a software radio device. The SDR device captures spectrum signals at the RF front end to facilitate management and control of the spectrum signals, thereby forming a digital IQ data stream based on analog-to-digital conversion of the spectrum signals.

[0088] At this time, the digitized IQ data stream and the unlicensed frequency band are associated to facilitate comparison between the digitized IQ data stream and the unlicensed frequency band, thereby defining the IQ data in the unlicensed frequency band based on the digitized IQ data stream and the unlicensed frequency band, thereby facilitating management and control of the IQ data in the unlicensed frequency band, and further processing the IQ data in the unlicensed frequency band.

[0089] refer to Figure 3 , in step S12, determining a corresponding baseband signal based on demodulation of the IQ data in the unlicensed frequency band;

[0090] In the specific implementation process of the present invention, the specific steps may be:

[0091] S121: Freeze the IQ data in the unlicensed frequency band and store the IQ data in the unlicensed frequency band;

[0092] S122: performing orthogonal demodulation on the IQ data in the unlicensed frequency band and outputting multiple signals;

[0093] S123: Determine a corresponding baseband signal based on the multiple signals.

[0094] In an embodiment of the present application, the IQ data in the unlicensed frequency band is frozen and stored to facilitate the management and control of the IQ data in the unlicensed frequency band. At this time, the IQ data in the unlicensed frequency band is orthogonally demodulated and multiple signals are output. The corresponding baseband signal is determined based on the multiple signals, thereby clarifying the baseband signal, and then the baseband signal is managed and controlled to facilitate further processing of the baseband signal.

[0095] Further, the determining the corresponding baseband signal according to the demodulation of the IQ data in the unlicensed frequency band further includes:

[0096] The IQ data in the unlicensed frequency band is orthogonally demodulated. At this time, the formula of the orthogonal demodulation algorithm is as follows:

[0097] y(t)=xI(t)cos(2πfct)-xQ(t)sin(2πfct),

[0098] Where y(t) is the baseband signal, xI(t) and xQ(t) are the real and imaginary parts of the IQ data, respectively, and fct is the carrier frequency.

[0099] In addition, IQ is a modulation method. In digital communication, it refers to a pair of phase-orthogonal modulation signals, that is, baseband signals. It is mainly used to improve spectrum utilization. IQ data records the time domain data of signal amplitude and phase characteristics.

[0100] refer to Figure 4 , in step S13, defining decoded data based on signal processing of the baseband signal;

[0101] In the specific implementation process of the present invention, the specific steps may be:

[0102] S131: freeze baseband signal;

[0103] S132: determining a boundary of a data symbol based on a baseband signal and a symbol synchronization algorithm, and aligning data according to the boundary of the data symbol;

[0104] S133: Correlate baseband signals and decoding algorithms;

[0105] S134: Decoding data is defined based on the baseband signal and signal processing of the decoding algorithm.

[0106] In an embodiment of the present application, a baseband signal is frozen and processed so as to determine the boundary of a data symbol based on the baseband signal and a symbol synchronization algorithm, and align the data according to the boundary of the data symbol, thereby performing alignment processing on the data.

[0107] Furthermore, the baseband signal and the decoding algorithm are associated; and the decoded data is defined based on the signal processing of the baseband signal and the decoding algorithm, so as to facilitate the management and control of the decoded data.

[0108] Among them, for aligning data according to the boundary of data symbols, a related algorithm is used, and the formula of the related algorithm is as follows:

[0109]

[0110] where ρk is the cross-correlation coefficient at time offset k and rn is the received signal sample.

[0111] In addition, for data decoding, first, deinterleaving is performed, which disperses the concentrated errors by rearranging the received binary data sequence so that the convolution decoder can correct errors more effectively, thereby improving the accuracy and reliability of OFDM demodulation. This process will disperse the bit errors that may occur in a concentrated manner due to channel interference to reduce the risk of error propagation; then, the deinterleaved data is input into the convolution decoder, and the data is decoded using its error correction capability to enhance the robustness of data transmission; finally, the demodulator restores the original frame based on the decoded data to ensure the integrity and accuracy of the data, thereby significantly improving the accuracy and reliability of the entire demodulation process.

[0112] refer to Figure 5 , S14: defining a wifi data frame according to the decoded data and the frame format of the Wi-Fi protocol;

[0113] In the specific implementation process of the present invention, the specific steps may be:

[0114] S141: freeze the decoded data;

[0115] S142: Associating the decoded data with the frame format of the Wi-Fi protocol;

[0116] S143: unpacking the decoded data according to the frame format of the Wi-Fi protocol, and outputting a plurality of key parameters;

[0117] S144: Define a wifi data frame according to multiple key parameters.

[0118] In an embodiment of the present application, the decoded data is frozen; the decoded data and the frame format of the Wi-Fi protocol are associated to facilitate overall management and control of the decoded data and the frame format of the Wi-Fi protocol, thereby unpacking the decoded data according to the frame format of the Wi-Fi protocol and outputting multiple key parameters; and the wifi data frame is defined according to the multiple key parameters.

[0119] The decoded data is unpacked according to the frame format of the Wi-Fi protocol, using the Viterbi algorithm, the formula of which is as follows:

[0120] Si,t+1=minj{Sj,t+cost(sj→si)},

[0121] where Si,t is the cumulative cost of state i at time t, and cost(sj→si) is the branch cost from state j to state i.

[0122] In addition, in the IQ data demodulation process of the present invention, the SDR device first captures the spectrum signal at the RF front end and performs analog-to-digital conversion to generate a digitized IQ data stream, and then estimates the carrier frequency offset (CFO) and corrects the clock mismatch between the receiver and the transmitter through the signal processing software on the Linux operating system platform. The corrected IQ data is then digitally down-converted and converted to the frequency domain, and multi-carrier (OFDM) demodulation is performed through fast Fourier transform (FFT), including channel estimation, equalization and symbol decoding, to restore the original data bits, complete data demodulation and extract Wifi data frames.

[0123] At the same time, in a preferred embodiment, wifi protocol matching refers to identifying the wifi protocol by identifying the data frame preamble and 802.11MAC header. This makes the identification more accurate. The spectrum IQ data collected by the SDR device is transmitted to the Linux operating system through the USB interface, and then the signal detection, signal demodulation, MAC layer decoding and other operations are implemented through the gnuradiol software. The IQ data collected by the SDR device is stored to facilitate subsequent signal demodulation. Users can download the collected IQ data binary file.

[0124] The collected signal data is demodulated accordingly according to the wireless protocol stack, and the WiFi protocol is matched after the demodulated data.

[0125] After the match is successful, the spectrum IQ data is restored to the wifi data frame, and then the device parameter information including the device mac address and signal strength is extracted from the wifi data frame. The spectrum signal demodulation algorithm is used to extract the MAC frame from the collected spectrum signal. According to the 802.11 protocol stack, the main content in the MAC frame is identified. The signal frame type can be obtained from the probe frame. It refers to the category of the captured WiFi signal. When the value of the last digit is 0, 4, or 8, it means that the captured WiFi signal is a "management" frame, a "control" frame, or a "data" frame, respectively.

[0126] Wireshark parses the extracted WiFi data frames based on the 802.11 protocol stack and identifies the main contents of the MAC frame. From the probe frame, we can obtain: device MAC address, WiFi signal strength, WiFi signal channel, signal frame type, and time.

[0127] refer to Figure 6 , S15: determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device;

[0128] In the specific implementation process of the present invention, the specific steps may be:

[0129] S151: freeze wifi data frame;

[0130] S152: Associating WiFi data frames and unlicensed frequency bands;

[0131] S153: Determine parameters of the unlicensed frequency band WiFi device according to the WiFi data frame and the unlicensed frequency band;

[0132] S154: Implementing real-time detection of the parameters of the unlicensed frequency band WiFi device based on the real-time response of the parameters of the unlicensed frequency band WiFi device.

[0133] In an embodiment of the present application, the WiFi data frame is frozen and managed. At this time, the WiFi data frame and the unlicensed frequency band are associated; the parameters of the unlicensed frequency band WiFi device are determined based on the WiFi data frame and the unlicensed frequency band; and the real-time detection of the parameters of the unlicensed frequency band WiFi device is achieved based on the real-time response of the parameters of the unlicensed frequency band WiFi device.

[0134] Therefore, the IQ data in the unlicensed frequency band is captured based on the SDR device; the corresponding baseband signal is determined based on the demodulation of the IQ data in the unlicensed frequency band; the decoded data is defined based on the signal processing of the baseband signal; the wifi data frame is defined according to the decoded data and the frame format of the Wi-Fi protocol; the parameters of the unlicensed frequency band wifi device are determined based on the wifi data frame to realize the real-time detection of the parameters of the unlicensed frequency band wifi device, thereby performing real-time detection on the unlicensed frequency band wifi device, and comprehensively covering the IQ data in the unlicensed frequency band, so as to ensure the detection accuracy of the unlicensed frequency band wifi device.

[0135] refer to Figure 7 , S16: Save the parameters and WiFi data frames of the unlicensed frequency band WiFi device;

[0136] In the specific implementation process of the present invention, the specific steps may be:

[0137] S161: freeze the parameters and WiFi data frames of the unlicensed frequency band WiFi device;

[0138] S162: Input the parameters of the unlicensed frequency band WiFi device and the WiFi data frame into the storage space;

[0139] S163: triggering the storage of parameters and WiFi data frames of unlicensed frequency band WiFi devices based on the storage space, and separately storing the parameters and WiFi data frames of unlicensed frequency band WiFi devices, and at the same time, triggering real-time supplementation and evidence collection of the storage space.

[0140] In the specific implementation process of the present invention, the parameters and WiFi data frames of the unlicensed frequency band WiFi devices are saved to facilitate the evidence collection of the unlicensed frequency band WiFi devices and WiFi data frames, thereby controlling the unlicensed frequency band WiFi devices.

[0141] At this time, the parameters and WiFi data frames of the unlicensed frequency band WiFi device are frozen; the parameters and WiFi data frames of the unlicensed frequency band WiFi device are input into the storage space, so as to introduce the storage space, thereby controlling the parameters and WiFi data frames of the unlicensed frequency band WiFi device with respect to the storage space.

[0142] At the same time, based on the storage space, the parameters and WiFi data frames of the unlicensed frequency band WiFi devices are triggered to be saved, and the parameters and WiFi data frames of the unlicensed frequency band WiFi devices are saved separately. At the same time, the real-time replenishment and evidence collection of the storage space are triggered to facilitate the evidence collection of the unlicensed frequency band WiFi devices and WiFi data frames, so as to control the unlicensed frequency band WiFi devices.

[0143] Therefore, the unlicensed spectrum IQ data is captured by the SDR device, the wifi data frame is restored from the spectrum data, and the parameters related to the hidden communication device are extracted from the wifi data frame. The method of the present invention is easy to operate, does not require expensive equipment, covers a wide frequency range, has a high recognition accuracy, and can detect and save the original data in real time to facilitate subsequent evidence collection.

[0144] In addition, an SDR device is used to capture the IQ data of the unlicensed spectrum, and the IQ data is demodulated and identified through the gnuradio software to detect whether there are wifi devices working in the unlicensed frequency band in the current space. Compared with the current detection methods, such as the detection method using a spectrum analyzer, the method of the present invention is easy to operate, does not require expensive equipment, covers a wide frequency range, has a high recognition accuracy, and can detect and save the original data in real time to facilitate subsequent evidence collection. In addition, hidden devices are effectively and conveniently detected. The method captures the IQ data of the unlicensed spectrum through an SDR device, uses gnuradio to demodulate and identify the IQ data, restores the wifi data frame from the spectrum data, and extracts the parameters related to the hidden communication device from the wifi data frame for analysis and display.

[0145] In another embodiment, it also includes:

[0146] Signal demodulation IQ data. Filter the IQ data that matches the currently monitored WiFi protocol from the demodulated IQ data.

[0147] In another embodiment of the detection method of the unlicensed frequency band WiFi device of the present invention, demodulating IQ data includes: transmitting the IQ data of each frequency band to the Linux operating system through the USB interface, and then signal demodulating the IQ data of each frequency band through the gnuradio software interface.

[0148] In another embodiment of the method for detecting unlicensed frequency band WiFi devices of the present invention, capturing IQ data of each frequency band in the unlicensed detection spectrum includes:

[0149] By dynamically switching the center frequency of the SDR software-defined radio device, each frequency band is scanned cyclically, and the IQ data of each frequency band in the unlicensed detection spectrum is captured, with a data capture interval of 50ms each time.

[0150] In another embodiment of the method for detecting an unlicensed frequency band WiFi device of the present invention, the parameters of the unlicensed frequency band WiFi device include: a device MAC address and a signal strength.

[0151] In an embodiment of the present invention, through the method in the embodiment of the present invention, IQ data in an unlicensed frequency band is captured based on an SDR device; a corresponding baseband signal is determined based on demodulation of the IQ data in the unlicensed frequency band; decoded data is defined based on signal processing of the baseband signal; a wifi data frame is defined based on the decoded data and a frame format of the Wi-Fi protocol; parameters of an unlicensed frequency band wifi device are determined based on the wifi data frame to achieve real-time detection of parameters of the unlicensed frequency band wifi device, thereby performing real-time detection on the unlicensed frequency band wifi device, and comprehensively covering the IQ data in the unlicensed frequency band, so as to ensure the detection accuracy of the unlicensed frequency band wifi device, and in addition, the parameters and wifi data frames of the unlicensed frequency band wifi device are saved, so as to collect evidence on the unlicensed frequency band wifi device and the wifi data frame, so as to control the unlicensed frequency band wifi device.

[0152] System Example

[0153] See also Figure 8 , Figure 8 It is a schematic diagram of the structural composition of the detection system of the unlicensed frequency band WiFi device in the embodiment of the present invention.

[0154] like Figure 8 As shown, a detection system for unlicensed frequency band WiFi devices, the detection system for unlicensed frequency band WiFi devices comprising:

[0155] A capture module 21, configured to capture IQ data in an unlicensed frequency band based on an SDR device;

[0156] A baseband signal module 22, configured to determine a corresponding baseband signal based on demodulation of IQ data in an unlicensed frequency band;

[0157] A decoding module 23, for defining decoded data based on signal processing of the baseband signal;

[0158] A wifi data frame module 24, used to define a wifi data frame according to the decoded data and the frame format of the Wi-Fi protocol;

[0159] A detection module 25, used to determine the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame, so as to realize real-time detection of the parameters of the unlicensed frequency band WiFi device;

[0160] The storage module 26 is used to store the parameters and WiFi data frames of the unlicensed frequency band WiFi device.

[0161] Example

[0162] See also Fig. 9 , refer to the following Fig. 9The electronic device 40 according to this embodiment of the present invention will be described. Fig. 9 The electronic device 40 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0163] like Fig. 9 As shown, the electronic device 40 is in the form of a general computing device. The components of the electronic device 40 may include but are not limited to: at least one processing unit 41, at least one storage unit 42, and a bus 43 connecting different system components (including the storage unit 42 and the processing unit 41).

[0164] The storage unit stores program codes, which can be executed by the processing unit 41, so that the processing unit 41 executes the steps according to various exemplary embodiments of the present invention described in the above “Embodiment Method” section of this specification.

[0165] The storage unit 42 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 421 and / or a cache memory unit 422 , and may further include a read-only memory unit (ROM) 423 .

[0166] The storage unit 42 may also include a program / utility 424 having a set (at least one) of storage modules 425, such storage modules 425 including but not limited to: an operating system, one or more application programs, other storage modules, and program data, each of which or some combination may include the implementation of a network environment.

[0167] Bus 43 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0168] The electronic device 40 may also communicate with one or more external devices (e.g., keyboards, pointing devices, Bluetooth devices, etc.), one or more devices that enable a user to interact with the electronic device 40, and / or any device that enables the electronic device 40 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 44. Furthermore, the electronic device 40 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 45. Fig. 9 As shown, the network adapter 45 communicates with other modules of the electronic device 40 via the bus 43. It should be understood that although Fig. 9Not shown, other hardware and / or software modules may be used in conjunction with the electronic device 40, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup planning systems.

[0169] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0170] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium can include: a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc. In addition, it stores computer program instructions, and when the computer program instructions are executed by a computer, the computer executes the above method.

[0171] In addition, the above describes in detail the detection method and system for unlicensed frequency band WiFi devices provided in the embodiments of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for detecting unlicensed frequency band WiFi devices, characterized in that: Applicable to the detection scenario of unlicensed frequency band WiFi devices; The detection method of the unlicensed frequency band WiFi device comprises: Capture IQ data in unlicensed frequency bands based on SDR equipment; Determining a corresponding baseband signal based on demodulation of IQ data in the unlicensed frequency band; defining decoded data based on signal processing of the baseband signal; Define the Wi-Fi data frame based on the decoded data and the frame format of the Wi-Fi protocol; Determine the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device; The parameters and WiFi data frames of unlicensed frequency band WiFi devices are saved.

2. The detection method of unlicensed frequency band WiFi device according to claim 1, characterized in that: The method of capturing IQ data in an unlicensed frequency band based on an SDR device includes: Locate SDR equipment; The SDR device captures the spectrum signal at the RF front end; A digital IQ data stream is formed based on analog-to-digital conversion of the spectrum signal; Correlate digitized IQ data streams and unlicensed spectrum; The IQ data in the unlicensed band is defined based on the digitized IQ data stream and the unlicensed band.

3. The detection method of unlicensed frequency band WiFi device according to claim 2, characterized in that: The determining a corresponding baseband signal according to demodulation of IQ data in the unlicensed frequency band includes: Freeze the IQ data in the unlicensed frequency band and store the IQ data in the unlicensed frequency band; Performing orthogonal demodulation on the IQ data in the unlicensed frequency band and outputting multiple signals; A corresponding baseband signal is determined based on the plurality of signals.

4. The method for detecting unlicensed frequency band WiFi devices according to claim 3, characterized in that: The determining of the corresponding baseband signal according to the demodulation of the IQ data in the unlicensed frequency band also includes: The IQ data in the unlicensed frequency band is orthogonally demodulated. At this time, the formula of the orthogonal demodulation algorithm is as follows: y(t)=xI(t)cos(2πfct)-xQ(t)sin(2πfct), Where y(t) is the baseband signal, xI(t) and xQ(t) are the real and imaginary parts of the IQ data, respectively, and fct is the carrier frequency.

5. The method for detecting unlicensed frequency band WiFi devices according to claim 1, characterized in that: The method of defining decoded data based on signal processing of the baseband signal comprises: Freeze baseband signal; Determine the boundary of the data symbol based on the baseband signal and the symbol synchronization algorithm, and align the data according to the boundary of the data symbol; Correlate baseband signals and decoding algorithms; Defining decoded data based on signal processing of the baseband signal and the decoding algorithm; Among them, for aligning data according to the boundary of data symbols, a related algorithm is used, and the formula of the related algorithm is as follows: where ρk is the cross-correlation coefficient at time offset k and rn is the received signal sample.

6. The method for detecting unlicensed frequency band WiFi devices according to claim 5, characterized in that: The method of defining a Wi-Fi data frame according to the decoded data and the frame format of the Wi-Fi protocol includes: Freeze the decoded data; Associate the decoded data with the frame format of the Wi-Fi protocol; Depacketize the decoded data according to the frame format of the Wi-Fi protocol and output multiple key parameters; Define wifi data frames based on multiple key parameters; The decoded data is unpacked according to the frame format of the Wi-Fi protocol, using the Viterbi algorithm, the formula of which is as follows: Si,t+1=minj{Sj,t+cost(sj→si)}, where Si,t is the cumulative cost of state i at time t, and cost(sj→si) is the branch cost from state j to state i.

7. The method for detecting unlicensed frequency band WiFi devices according to claim 6, characterized in that: The method of determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device includes: Freeze wifi data frame; Associate wifi data frames and unlicensed frequency bands.

8. The method for detecting unlicensed frequency band WiFi devices according to claim 7, characterized in that: The method of determining the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame to achieve real-time detection of the parameters of the unlicensed frequency band WiFi device also includes: Determine the parameters of the unlicensed frequency band WiFi device according to the WiFi data frame and the unlicensed frequency band; Based on the real-time response of the parameters of the unlicensed frequency band WiFi device, the real-time detection of the parameters of the unlicensed frequency band WiFi device is achieved.

9. The method for detecting unlicensed frequency band WiFi devices according to claim 8, characterized in that: The storing of parameters and WiFi data frames of unlicensed frequency band WiFi devices includes: Freeze the parameters and WiFi data frames of unlicensed frequency band WiFi devices; Input the parameters and WiFi data frames of the unlicensed frequency band WiFi device into the storage space; The parameters and WiFi data frames of unlicensed frequency band WiFi devices are triggered based on the storage space, and the parameters and WiFi data frames of unlicensed frequency band WiFi devices are saved separately. At the same time, the real-time supplement and evidence collection of the storage space are triggered.

10. A detection system for unlicensed frequency band WiFi devices, characterized in that: The detection system of the unlicensed frequency band WiFi device is applied to the detection method of the unlicensed frequency band WiFi device as claimed in any one of claims 1 to 9, and the detection system of the unlicensed frequency band WiFi device includes: A capture module, used to capture IQ data in unlicensed frequency bands based on SDR equipment; A baseband signal module, used to determine a corresponding baseband signal according to the demodulation of the IQ data in the unlicensed frequency band; A decoding module, for defining decoded data based on signal processing of the baseband signal; The wifi data frame module is used to define the wifi data frame according to the decoded data and the frame format of the Wi-Fi protocol; A detection module, used to determine the parameters of the unlicensed frequency band WiFi device based on the WiFi data frame, so as to realize the real-time detection of the parameters of the unlicensed frequency band WiFi device; The saving module is used to save the parameters and WiFi data frames of the unlicensed frequency band WiFi device.

Images