阅读说明：本技术 一种基于前导码的WiFi信道干扰方法及系统 (Lead code based WiFi channel interference method and system ) 是由 李涛 朱瑞驰 俞佳宝 彭林宁 于 2021-09-13 设计创作，主要内容包括：本申请公开了一种基于前导码的WiFi信道干扰方法与系统,该方法通过在指定信道连续发送IEEE802.11协议前导码中的短训练字段(L-STF),使该信道的所有无线局域网设备判断当前信道为忙从而无法利用WiFi进行网络通信。干扰系统可以实现对指定信道进行精确干扰,以及在2.4G或5GWiFi频段下的全频段干扰。指定信道的精确干扰通过扫描当前网络环境中的无线局域网参数,选择干扰目标所在的信道,最后通过功率放大模块放大干扰信号,对该信道进行攻击,使附近该信道的所有无线局域网设备无法进行正常的网络通信,从而有效地消他人利用WiFi窃取隐私安全的可能性。(The method continuously sends a short training field (L-STF) in the preamble of an IEEE802.11 protocol on a designated channel, so that all wireless local area network equipment of the channel judges that the current channel is busy and cannot utilize WiFi to carry out network communication. The interference system can realize accurate interference on a specified channel and full-band interference under a 2.4G or 5GWIFi frequency band. The precise interference of the appointed channel selects the channel where the interference target is located by scanning the wireless local area network parameters in the current network environment, and finally amplifies the interference signal through the power amplification module to attack the channel, so that all the wireless local area network devices nearby the channel can not carry out normal network communication, and the possibility that others steal privacy security by utilizing WiFi is effectively eliminated.)

1. A WiFi channel interference method based on a lead code is characterized in that: the method comprises the following steps:

step 1: obtaining WiFi network parameters of the current environment;

step 2: generating an L-STF interference signal; generating an L-STF time domain signal, and putting the generated signal into a memory;

and step 3: the interfering signal is continuously transmitted on the target channel.

2. The preamble-based WiFi channel interference method of claim 1, wherein: the step 1: the specific steps for acquiring the WiFi network parameters in the current environment are as follows: and scanning the surrounding wireless network environment by using a wireless network card, scanning each channel in turn, acquiring the becon frames sent by different WiFi devices, analyzing the becon frames according to the IEEE802.11 protocol, and acquiring the SSIDs and the channels of the different WiFi devices.

3. The preamble-based WiFi channel interference method of claim 1, wherein: the step 2: the specific method for generating the L-STF interference signal comprises the following steps: the time domain signal is generated by using 12 subcarriers in OFDM and using an inverse Fourier transform function, and the generated time domain signal is repeated 10 times to form an L-STF frame signal in a preamble, wherein the duration time is 8 us.

4. The preamble-based WiFi channel interference method of claim 1, wherein: the step 3: the continuously transmitting the interference signal on the target channel includes: and transmitting the interference signal in the selected target channel and transmitting the interference signal in the full frequency band.

5. The preamble-based WiFi channel interference method of claim 4, wherein: the specific method for transmitting the interference signal in the full frequency band comprises the following steps: in a 2.4g frequency band, an L-STF interference signal needs to be transmitted on three channels of 3, 7 and 11 so as to realize signal coverage of a full frequency band; in the 5g frequency band, the L-STF interference signal needs to be transmitted on a total of 13 channels, so that the signal coverage of the full frequency band can be realized.

6. The WiFi channel interference system based on the lead code is characterized by comprising an input unit, a display unit, a memory, a processor, an interference signal output module and a interference signal amplification module.

7. A preamble based WiFi channel interference system according to claim 6, characterized in that:

the input unit is used for selecting a target channel needing interference and sending an interference signal on a channel where an interference target is located; for selecting full band interference; and the display unit is used for displaying the scanned SSID of the wireless equipment and the channel where the SSID is located.

8. A preamble based WiFi channel interference system according to claim 6, characterized in that:

the memory is used for storing a complete interference program and a time domain sampling value of an interference signal, the interference program realizes a WiFi channel interference method based on a lead code, and the method comprises three steps of obtaining WiFi network parameters of the current environment, generating an L-STF interference signal and continuously sending the interference signal in a target channel; the processor is used for communicating with each module and executing the interference program in the memory.

9. A preamble based WiFi channel interference system according to claim 6, characterized in that:

the WiFi signal capturing module is used for scanning and capturing becon frames sent by wireless equipment on different channels and transmitting the analyzed becon frames to the processor;

the interference signal output module is used for outputting an L-STF interference signal in a specified channel, the plurality of output modules can output the interference signal in parallel in a plurality of channels, and the number of the output modules is determined by the number of target channels;

the interference signal amplification module is used for amplifying interference signal power, improving interference effect and interference range, and realizing through-wall interference, and the number of the amplification modules is consistent with that of the output modules.

Technical Field

The application relates to the technical field of wireless networks, in particular to a WiFi channel interference method and system based on lead codes.

Background

With the development of mobile internet and the continuous increase of the number of terminals, the application of technologies such as internet of things, artificial intelligence, big data, edge calculation and the like, the wireless network bearing capacity faces unprecedented demands. Meanwhile, the new crown epidemic situation affects the world, meanwhile, the pace of ICT construction is promoted from the other aspect, the pace of digital transformation is accelerated in various mainstream industries such as education, medical treatment, manufacturing and finance, so that the great change is met, the projects such as remote office, online education, a digital platform and intelligent medical treatment also need strong wireless network support, and the latest generation WiFi equipment has epoch-making product characteristics and can meet the requirements of high speed, intellectualization and high-concurrency novel business.

At present, the consumer-grade WiFi6 router accounts for 14.7% of the market share of the router, the epidemic situation also promotes the network requirements of the entertainment game industry and the digital television, and the WiFi6 also provides a high-quality network experience for consumer-grade users. IDC forecasts that in 2021, consumer-grade router WiFi6 products will continue to expand market share, reaching market size of nearly $ 8.5 billion in the chinese market.

However, with the popularization and promotion of WiFi, the exposed potential safety hazard is more and more serious. For example, a lawbreaker may connect a previously installed eavesdropping device using a WiFi network and continuously transmit confidential information that violates individual privacy and affects social security.

For such problems, the conventional processing method uses two interference signals, the first interference signal is called persistent interference, the interfered link layer signal is composed of a random bit stream and is sent out after being processed by a physical layer modulation and power amplification module, the second interference signal is called deceptive interference, the interference signal complies with the IEEE802.11 protocol, and the sending device mistakenly regards the channel as busy by transmitting an interference frame uninterruptedly so as not to send data, thereby finally achieving the effect of blocking the channel. However, both methods have the disadvantages of large power consumption, insignificant interference effect and incapability of realizing full-band coverage.

Thus, there is an overall need for an efficient interference method for a given channel and for 2.4G or 5G full band interference, and an overall need for a complete system with lower power consumption that achieves stable continuous WiFi channel interference.

Disclosure of Invention

In order to solve the above problems, the present invention discloses a WiFi channel interference method based on lead code, which comprises three steps of obtaining WiFi network parameters of the current environment, generating L-STF interference signal, and continuously sending interference signal in the target channel, wherein:

acquiring the current environment WiFi network parameters comprises scanning a WiFi channel, acquiring a beacon frame, analyzing the beacon frame and acquiring related information of WiFi equipment.

Generating the L-STF interference signal includes generating an L-STF time domain signal, placing the generated signal in memory.

The transmitting of the interference signal in the target channel includes transmitting the interference signal in the designated channel and transmitting the interference signal in the full frequency band.

The invention further improves that: the specific steps for acquiring the WiFi network parameters of the current environment are as follows: and scanning the surrounding wireless network environment by using a wireless network card, scanning each channel in turn, acquiring the becon frames sent by different WiFi devices, analyzing the becon frames according to the IEEE802.11 protocol, and acquiring the SSIDs and the channels of the different WiFi devices.

The invention further improves that: the specific method for generating the L-STF interference signal comprises the following steps: according to the IEEE802.11 protocol, 12 subcarriers in OFDM are used, an inverse Fourier transform function is used for generating a time domain signal, and the generated time domain signal is repeated 10 times to form an L-STF frame in a preamble, wherein the duration of the L-STF frame is 8 us.

The invention further improves that: the specific method for interfering the designated frequency band comprises the following steps: and continuously sending the interference signal on the target channel by acquiring the channel where the nearby target WiFi equipment is located.

The invention further improves that: the specific method for interfering the full frequency band comprises the following steps: in the 2.4g frequency band, the L-STF interference signal needs to be transmitted on three channels of 3, 7 and 11, so that the signal coverage of the full frequency band can be realized. In the 5g frequency band, the L-STF interference signal needs to be transmitted on 13 channels, so that the full-frequency-band signal coverage can be realized.

A preamble-based WiFi channel interference system, comprising:

an input unit: the method comprises the steps of selecting a target needing to send interference, and sending an interference signal in a channel where the interference target is located; for selecting full band interference.

A display unit: for displaying the SSID scanned to the wireless device and the channel on which it is located.

A memory: the interference program is used for storing a complete interference program and a time domain sampling value of an interference signal, and the interference program realizes the WiFi channel interference method based on the lead code.

A processor: communicating with each module and executing the interference program in the memory.

WiFi signal acquisition module: for scanning and capturing the becon frames transmitted by the wireless devices on different channels in the space, and transmitting the parsed becon frames to the processor.

An interference signal output module: for outputting the L-STF interference signal on a designated channel, the plurality of output modules may output the interference signal in parallel on a plurality of channels.

The interference signal amplification module: the power amplifier is used for amplifying interference signal power, improving interference effect and interference range, realizing through-wall interference, and the number of the amplification modules is consistent with that of the output modules.

The invention has the beneficial effects that:

compared with the traditional WiFi interference method, the CCA mechanism of the wireless equipment can be triggered by a lower signal energy threshold value, so that the wireless equipment can judge that the channel is busy and cannot normally communicate, the requirement on the interference signal strength is lower, the requirement on the power consumption of the interference equipment is greatly reduced, the interference effect is obvious, and a certain through-the-wall interference effect is achieved.

Drawings

Fig. 1 is a flow chart of a WiFi channel interference method based on a preamble;

fig. 2 is a block diagram of a detailed implementation flow of an interference method;

fig. 3 is a block diagram of a WiFi channel interference system architecture based on a preamble;

FIG. 4 is a time domain waveform diagram of an L-STF interference signal;

fig. 5 is a schematic diagram of 2.4GWiFi channel interference coverage;

fig. 6 is a diagram of an ieee802.11ac physical layer packet structure.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

As shown in fig. 1, a WiFi channel interference method based on a preamble includes three steps of obtaining WiFi network parameters of a current environment, generating an L-STF interference signal, and continuously transmitting the interference signal in a target channel.

Acquiring the current environment WiFi network parameters comprises scanning a WiFi channel, acquiring a beacon frame, analyzing the beacon frame and acquiring related information of WiFi equipment.

Generating the L-STF interfering signal includes generating an L-STF time domain signal with 10 repeating sequences forming a complete signal.

Transmitting the interference signal on the target channel includes transmitting the interference signal on the designated channel and transmitting the interference signal in the full frequency band.

As shown in fig. 2, the specific implementation method is as follows:

scanning surrounding wireless network environment, scanning each channel, acquiring beacon frames sent by different WiFi equipment, analyzing the beacon frames to acquire SSIDs (service set identifiers) and channels of the different WiFi equipment, and specifically comprising the following steps:

(1) firstly, scanning the surrounding wireless network environment by using a wireless network card;

(2) scanning each channel in turn;

(3) acquiring beacon frames sent by different WiFi equipment;

(4) parsing the becon frame following the IEEE802.11 protocol;

(5) acquiring SSIDs and channels of different WiFi devices;

(6) and outputting the SSID and the channel through a display unit.

As shown in fig. 6, the L-STF interference signal belongs to a part of the preamble of the IEEE802.11 physical layer, and is generally used for packet detection, coarse synchronization, and automatic gain control.

The specific method for generating the L-STF interference signal comprises the following steps: according to the IEEE802.11 protocol, 12 subcarriers in OFDM are used, a time domain signal is generated by using an inverse fourier transform function, the generated time domain signal is repeated 10 times to form an L-STF frame signal in a preamble, the duration of an interference signal is 8us, and a time domain waveform for generating the interference signal is shown in fig. 4, and the specific steps are as follows:

(1) defining a subcarrier sequence L _ STF ═ 0,0,0,0,0,1+1i,0,0,0, -1-1i,0,0,0, -1-1i,0,0,0,1+1i,0,0,0,0,0,0, -1-1i,0,0,0, -1-1i,0,0,0,1+1i,0,0,0,1+1i,0,0,0, 0,0,0,0 ];

(2) performing inverse fourier operation on the time domain signal to obtain a time domain signal L _ STF _ time, where L _ STF _ time is a sequence of 16 elements and a repetition length of 64, that is, includes 4 repetition sequences:

L_STF_time＝ifft(L_STF,64)；

(3) splicing the sequence to obtain a sequence containing 10 repeated code elements, namely a final L-STF sequence:

L_STF_time＝[L_STF_time,L_STF_time,L_STF_time(1:32)]；

the user selects to interfere with a designated channel or to interfere with the full band through the input unit.

The specific method for interfering the designated frequency band comprises the following steps: and outputting the generated interference signal at a sampling rate of 20Mhz, wherein the central frequency is the central frequency of the frequency band.

The specific method for interfering the full frequency band comprises the following steps: in the 2.4g frequency band, as shown in fig. 5, the L-STF interference signal needs to be transmitted on three channels of 3, 7, and 11, so as to achieve full-band signal coverage. In the 5g frequency band, for example, in china, the full-frequency band coverage can be achieved by transmitting L-STF interference signals on 13 channels.

As shown in fig. 3, the present invention also provides a WiFi channel interference system based on preamble, including:

an input unit: the method comprises the steps of selecting a target needing to send interference, and sending an interference signal in a channel where the interference target is located; full band interference is selected.

A display unit: and the wireless device is used for displaying the SSID of the scanned wireless device and the channel where the wireless device is located.

The input unit and the display unit adopt a capacitive touch screen, the processor transmits data to be displayed to the touch screen through serial port communication, and the communication flow follows the communication protocol of the capacitive touch screen. When the user selects the channel needing interference, the touch screen transmits the selected result to the processor through serial port communication.

A processor: communicating with each module and executing the interference program in the memory.

A memory: the interference program realizes the WiFi channel interference method based on the lead code, and comprises three steps of obtaining WiFi network parameters of the current environment, generating an L-STF interference signal and continuously sending the interference signal on a target channel, wherein the interference signal data storage form is 160 single-precision floating point numbers.

WiFi signal acquisition module: the invention is used for scanning and capturing the becon frames sent by the wireless devices on different channels in the space and transmitting the analyzed becon frames to the processor, a WiFi network card supporting an IEEE802.11ac protocol is used for capturing WiFi signals in the space, and the network card analyzes data according to the IEEE802.11 protocol.

An interference signal output module: the multi-channel interference signal generating module is used for outputting an L-STF interference signal in a specified channel, a plurality of output modules can output the interference signal in parallel in the plurality of channels, the output modules use radio frequency chips supporting WiFi2.4g or 5g frequency bands, and the signal output bandwidth of the chips is at least 20 MHz.

The interference signal amplification module: the power amplification module is used for amplifying interference signal power, improving interference effect and interference range and realizing through-wall interference, the number of the amplification modules is consistent with that of the output modules, each signal amplification module comprises a power amplification circuit and a transmitting antenna, the power amplification circuit amplifies 2.4g or 5g frequency band high-frequency signals, and the antenna realizes conversion from circuit signals to electromagnetic wave signals.

The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.