CN114448529A - Wi-Fi channel detection system and method - Google Patents

Abstract

The invention provides a Wi-Fi channel detection system and a method, wherein the system comprises: the phase-locked loop circuit outputs at least one local oscillator signal with set frequency in a time-sharing manner under the control of the microcontroller; the mixer circuit mixes the local oscillator signal with the input Wi-Fi signal to obtain an intermediate frequency signal; the low-pass filter filters the intermediate frequency signal; the microcontroller is provided with an A/D converter which samples the filtered intermediate frequency signal; and the microcontroller determines a Wi-Fi channel occupied by the Wi-Fi signal according to the AD sampling result corresponding to different phase-locked loop frequency settings. Thus, the ultrahigh frequency and ultrahigh frequency signals of the Wi-Fi signals are subjected to down-conversion through the mixer circuit to obtain intermediate frequency signals, and then sampling and identification are carried out; this greatly reduces the sampling rate of the a/D converter and the computational power requirements of the microcontroller; reliable performance and low cost.

Description

A Wi-Fi channel detection system and method

technical field

The present invention relates to the technical field of wireless communication, and in particular, to a Wi-Fi channel detection system and method.

Background technique

Wi-Fi-based visible light communication technology (VLC) needs to down-convert UHF or UHF Wi-Fi signals in the 2.4GHz or even 5GHz band to a high frequency range within the LED response frequency, using visible light as the signal transmission medium to communicate. Since the bandwidth of LEDs is very limited and relatively fixed, accurate detection of the Wi-Fi channel is required before downconversion.

However, the existing Wi-Fi channel detection is to directly sample the Wi-Fi signal according to the Nyquist criterion and then perform spectrum analysis, which is very demanding on the sampling rate of the A/D converter and the computing power of the processor.

SUMMARY OF THE INVENTION

The problem solved by the present invention is that the existing Wi-Fi channel detection requires too much sampling rate and computing resources.

In order to solve the above problems, the present invention first provides a Wi-Fi channel detection system, which includes:

A phase-locked loop circuit, a mixer circuit, a low-pass filter and a microcontroller, the phase-locked loop circuit outputs at least one local oscillator signal with a set frequency in time division under the control of the microcontroller; the mixer The frequency converter circuit mixes the local oscillator signal and the input Wi-Fi signal to obtain an intermediate frequency signal; the low-pass filter filters the intermediate frequency signal; the microcontroller is provided with an A/D conversion The A/D converter samples the filtered intermediate frequency signal; the microcontroller determines the Wi-Fi occupied by the Wi-Fi signal according to the AD sampling results corresponding to different PLL frequency settings -Fi channel.

In this way, the UHF and UHF signals of the Wi-Fi signal are down-converted into intermediate frequency signals through the mixer circuit, and then sampled and identified, which greatly reduces the sampling rate of the A/D converter and the microcontroller. Computing power requirements; reliable performance and low cost.

Preferably, the system further includes:

an RF single-pole double-throw switch, the input end of which is connected to the mixer circuit, one output end is connected to the low-pass filter, and the other output end is used as the output end of the system; the microcontroller controls the RF single-pole switch The double-throw switch turns on the mixer circuit and the low-pass filter during Wi-Fi channel detection, and turns on the mixer circuit and the low-pass filter after determining the Wi-Fi channel occupied by the Wi-Fi signal. output of the system.

Preferably, the microcontroller controls the frequency of the local oscillator signal output by the phase-locked loop circuit through a three-wire serial interface.

Secondly, a Wi-Fi channel detection method based on the above-mentioned Wi-Fi channel detection system is provided, which includes:

The microcontroller obtains the center frequency of the available Wi-Fi channels;

The microcontroller controls the local oscillator signal output by the phase-locked loop circuit, so that the frequency of the local oscillator signal is the same as the center frequency;

The microcontroller reads the AD sampling result corresponding to the center frequency output by the A/D converter;

The microcontroller controls the phase-locked loop to traverse and output the local oscillator signals of the center frequency of all the available Wi-Fi channels, and obtain the corresponding AD sampling results;

The occupied Wi-Fi channel is determined according to the AD sampling results corresponding to all the available Wi-Fi channels.

In this way, the UHF and UHF signals of Wi-Fi signals are down-converted into intermediate frequency signals, and then sampled and identified; this greatly reduces the requirements for sampling rate and computing power; the performance is reliable and the cost is low.

Preferably, the microcontroller controls the RF SPDT switch to turn on the mixer circuit and the low-pass filter when the Wi-Fi channel is detected; after determining the Wi-Fi channel occupied by the Wi-Fi signal, turn on the the mixer circuit and the output of the system.

Preferably, the AD sampling frequency and sampling duration of the AD sampling results corresponding to each of the available Wi-Fi channels are the same.

Preferably, according to the AD sampling results corresponding to all the available Wi-Fi channels, the occupied Wi-Fi channels are determined, including:

Determine the signal fluctuation degree coefficient according to the AD sampling result;

Sort the fluctuation degree coefficients of the available Wi-Fi channels according to the frequency band range of the available Wi-Fi channels;

Binarize the sorted volatility coefficients according to the mean value of the volatility coefficients to obtain a binarization sequence of the volatility coefficients;

The occupied Wi-Fi channel is determined according to the binarization sequence of the fluctuation degree coefficient.

Preferably, the signal fluctuation degree coefficient is determined according to the AD sampling result, including:

Get the first threshold;

The fluctuation degree coefficient is calculated according to the first threshold and the AD sampling result.

Preferably, the calculation formula of the fluctuation degree coefficient is:

Wherein, F is the fluctuation degree coefficient, x _k , x _k+1 are the sampling values in the AD sampling result, k is the serial number of the sampling values, and n is the total number of sampling values.

Among them, the function δ:

The threshold is a first threshold, and the value of the first threshold is determined according to the actual situation or preset.

Preferably, the occupied Wi-Fi channel is determined according to the binarization sequence of the fluctuation degree coefficient, including:

Obtain the binarized templates of all the available Wi-Fi channels;

If the binarization sequence of the fluctuation degree coefficient matches the binarization template, it is determined that the Wi-Fi signal occupied by the Wi-Fi signal is the Wi-Fi channel corresponding to the binarization template.

Description of drawings

1 is a schematic structural diagram of a Wi-Fi channel detection system according to an embodiment of the present invention;

2 is a flowchart of a Wi-Fi channel detection method according to an embodiment of the present invention;

3 is a schematic diagram of an exemplary Wi-Fi channel distribution according to an embodiment of the present invention;

4 is a flowchart of a Wi-Fi channel detection method S500 according to an embodiment of the present invention;

5 is a histogram of signal fluctuation distribution according to an embodiment of the present invention;

6 is a binarization sequence diagram of an exemplary fluctuation degree coefficient according to an embodiment of the present invention;

FIG. 7 is a flowchart of a Wi-Fi channel detection method S510 according to an embodiment of the present invention;

8 is a flowchart of a Wi-Fi channel detection method S530 according to an embodiment of the present invention;

FIG. 9 is a binarization sequence diagram of the fluctuation degree coefficient of channel 1 according to an embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Wi-Fi-based visible light communication technology down-converts UHF or UHF Wi-Fi signals in the 2.4GHz or even 5GHz band to a high frequency range within the LED response frequency, and uses visible light as the signal transmission medium for communication.

In this way, when restoring the intermediate frequency signal transmitted by the coaxial cable, the signal from the same wireless hotspot can be up-converted to different Wi-Fi channels, so as to avoid interference caused by channel congestion and improve communication quality.

However, because the bandwidth of LED is very limited and relatively fixed, it is necessary to accurately determine the occupied Wi-Fi channel before down-conversion. Otherwise, once the Wi-Fi channel is inaccurate, it will not fall within the LED response frequency after down-conversion. .

However, in the existing Wi-Fi channel detection, the spectrum analysis is usually performed directly after sampling the Wi-Fi signal according to the Nyquist criterion, which has very strict requirements on the sampling rate of the A/D converter and the computing power of the processor; To achieve such a requirement means to use expensive A/D converters and processors, which brings great inconvenience.

An embodiment of the present application provides a Wi-Fi channel detection system, which is used to detect a Wi-Fi channel occupied by a Wi-Fi signal. As shown in FIG. 1, it is a schematic structural diagram of a Wi-Fi channel detection system according to an embodiment of the present invention; wherein, the Wi-Fi channel detection system includes:

A phase-locked loop circuit 1, a mixer circuit 2, a low-pass filter 3 and a microcontroller 4, the phase-locked loop circuit 1 under the control of the microcontroller 4 time-divisions to output at least one set frequency of the present. oscillator signal; the mixer circuit 2 mixes the local oscillator signal and the input Wi-Fi signal to obtain an intermediate frequency signal; the low-pass filter 3 filters the intermediate frequency signal; the micro-controller The device 4 is provided with an A/D converter 5, and the A/D converter 5 samples the filtered intermediate frequency signal; the microcontroller 4 determines the corresponding AD sampling results according to different set frequencies. Wi-Fi channel occupied by the Wi-Fi signal.

Wherein, the signal input end of the mixer circuit is connected to the Wi-Fi signal, and the local oscillator input end of the mixer circuit is connected to the local oscillator signal generated by the phase-locked loop circuit. The output end of the low-pass filter is connected to the detection pin of the ADC (A/D converter 5 ) of the microcontroller.

Preferably, the output signal of the low-pass filter is sampled by the ADC, the AD sampling result is processed, and the Wi-Fi channel occupied in the current communication is judged according to the code logic.

Wherein, the output of the low-pass filter is connected to the ADC pin of the microcontroller.

Among them, the microcontroller adopts STM32F103C8T6, which integrates ADC unit inside, which can control ADC through timer and DMA bus to achieve high-speed and stable continuous sampling. In this way, only the STM32F103C8T6 microcontroller can provide enough memory and computing power to process the sampled data.

In this way, the UHF and UHF signals of the Wi-Fi signal are down-converted into intermediate frequency signals through the mixer circuit, and then sampled and identified; this greatly reduces the sampling rate and micro-frequency of the A/D converter. Controller computing power requirements; reliable performance and low cost.

Preferably, as shown in FIG. 1 , the system further includes: an RF SPDT switch 6 , the input end of which is connected to the mixer circuit 2 , one output end is connected to the low-pass filter 3 , and the other is connected to the mixer circuit 2 . The output terminal is used as the output terminal of the system; the microcontroller 4 controls the RF SPDT switch to turn on the mixer circuit 2 and the low-pass filter 3 when the Wi-Fi channel is detected. After the Wi-Fi channel occupied by the Wi-Fi signal, the mixer circuit 2 and the output end of the system are turned on.

Wherein, the input end of the RF SPDT switch is connected to the intermediate frequency signal output by the mixer. The output of the RF SPDT switch is divided into two channels, one output is used as the effective signal output of the entire channel detection circuit, and the other output is connected to the input end of the low-pass filter. The microcontroller controls the on-off of the RF SPDT switch; the microcontroller controls the conduction direction of the RF SPDT switch by changing the level of the enabling terminal of the RF SPDT switch.

In this way, when the Wi-Fi channel occupied by the input Wi-Fi signal needs to be detected, the intermediate frequency signal is input to the low-pass filter for filtering and subsequent processing, so as to accurately detect the occupied Wi-Fi channel; After the Fi channel, the IF signal is directly output. In this way, through the switching of the RF SPDT switch, two independent functions of Wi-Fi channel detection and intermediate frequency signal output can be realized, which greatly increases the flexibility of the Wi-Fi channel detection system.

In this way, through the RF SPDT switch, the detection circuit can be isolated from the effective signal path of the system, and the influence of the detection circuit on the effective signal quality in the non-channel detection state can be reduced.

Preferably, the microcontroller 4 controls the frequency of the local oscillator signal of the phase-locked loop circuit 1 through a three-wire serial interface.

In this way, when the system enters the channel detection state, the microcontroller will control the RF SPDT switch to conduct the signal path from the mixer circuit to the low-pass filter. During the channel detection process, the microcontroller will control the change of the phase-locked loop. The frequency of the output signal, traverses the center frequency of all available Wi-Fi channels, and the AD sampling result will be calculated and processed by the microcontroller to obtain a binarized table that measures the signal strength of each channel. After the sampling of each channel is completed, the microcontroller will judge the Wi-Fi channel used in the current communication according to the code logic. If the judgment is successful, it will control the phase-locked loop to output the working frequency of the corresponding channel, otherwise it will resume the channel detection. previous operating frequency. After the above channel detection process is over, the microcontroller will control the RF SPDT switch to cut off the connection with the low-pass filter, and the system outputs the IF signal corresponding to the Wi-Fi working channel.

The embodiment of the present application provides a Wi-Fi channel detection system method, which is performed on the basis of the Wi-Fi channel detection system described in the foregoing content of the present invention, and the Wi-Fi channel detection method is described in detail below.

As shown in FIG. 2, a Wi-Fi channel detection method based on the above-mentioned Wi-Fi channel detection system includes:

S100, the microcontroller obtains the center frequency of the available Wi-Fi channel;

Different protocol standards will retain different open channels, these open channels are available Wi-Fi channels; the frequency center of the channel is the frequency at the center of the Wi-Fi channel.

Wherein, the microcontroller pre-stores the center frequency of the available Wi-Fi channel, which can be directly obtained when needed.

Taking Wi-Fi working under the 802.11g protocol as an example, the channels open to use in China are 1-13, which are evenly distributed in the 2412MHz-2472MHz frequency band, the center frequency of the channels is 5MHz apart, and the frequency ranges covered by each channel overlap each other. The specific distribution is shown in Figure 3.

S200, the microcontroller controls the local oscillator signal output by the phase-locked loop circuit, so that the frequency of the local oscillator signal is the same as the center frequency;

That is, the output of the phase-locked loop circuit is the local oscillator signal of the center frequency of the available Wi-Fi channel.

S300, the microcontroller reads the AD sampling result corresponding to the center frequency output by the A/D converter;

That is, the output of the phase-locked loop circuit is the local oscillator signal of the center frequency of the available Wi-Fi channel. In this way, the AD sampling result is the AD sampling result corresponding to the available Wi-Fi channel/center frequency.

It should be noted here that, in order to ensure sampling, the duration of the phase-locked loop circuit outputting the local oscillator signal at the center frequency should not be less than the sampling duration.

S400, the microcontroller controls the phase-locked loop to traverse and output the local oscillator signals of the center frequency of all the available Wi-Fi channels, and obtain corresponding AD sampling results;

That is to re-execute steps S200-S300, change the center frequency of an available Wi-Fi channel each time, and obtain the AD sampling result of the available Wi-Fi channel; repeat the cycle until all available Wi-Fi channels are obtained up to the AD sampling result.

Taking Wi-Fi working under the 802.11g protocol as an example, the channels 1-13 are open to use in China, that is, all 13 AD sampling results of Wi-Fi channels 1-13 are obtained.

S500: Determine the occupied Wi-Fi channel according to AD sampling results corresponding to all the available Wi-Fi channels.

The AD sampling results can reflect the signal strengths of different Wi-Fi channels, thereby determining the Wi-Fi channels occupied by the Wi-Fi signals.

Taking the Wi-Fi signal conforming to the 802.11g protocol as an example, the channel bandwidth is 20MHz, and the intermediate frequency signal obtained by mixing the Wi-Fi signal with the local oscillator signal of the current channel center frequency contains the frequency component of DC-10MHz. The obtained IF signal is input into the low-pass filter to intercept the low-frequency part and then input to the ADC to detect the signal amplitude. At this time, the ADC performs sampling at the frequency that satisfies the sampling theorem, and obtains the intensity sequence of the input signal within a period of time, and the microcontroller will calculate and process the above-mentioned sampling sequence. Repeat the above steps, traverse all available Wi-Fi channels, and determine the channel number occupied in the current communication according to the signal strength distribution.

In this way, there is no need to obtain the complete spectrum information of the Wi-Fi signal, but only the signal strength near the center frequency of each channel needs to be detected, thereby greatly reducing the computing power requirements.

In this way, by down-converting the UHF and UHF signals of Wi-Fi signals into intermediate frequency signals, and then sampling and identifying them; this greatly reduces the requirements for sampling rate and computing power; the performance is reliable and the cost is low.

Preferably, the microcontroller controls the RF SPDT switch to turn on the mixer circuit and the low-pass filter when the Wi-Fi channel is detected; after determining the Wi-Fi channel occupied by the Wi-Fi signal, turn on the the mixer circuit and the output of the system.

In this way, the detection circuit can be isolated from the effective signal path of the system, and the influence of the detection circuit on the effective signal quality in the non-channel detection state can be reduced.

Preferably, the AD sampling frequency and sampling duration of the AD sampling results corresponding to each of the available Wi-Fi channels are the same. In this way, a signal strength sequence with the same number of points can be obtained as the AD sampling result.

Preferably, as shown in FIG. 4 , in S500, according to AD sampling results corresponding to all the available Wi-Fi channels, determine the occupied Wi-Fi channels, including:

S510, determine a signal fluctuation degree coefficient according to the AD sampling result;

Among them, the fluctuation degree coefficient is used to directly reflect the magnitude of the sampled signal strength; the larger the fluctuation degree coefficient, the greater the signal strength.

S520, binarize the fluctuation degree coefficient according to the mean value of the fluctuation degree coefficient to obtain a binarization sequence of the fluctuation degree coefficient;

Since different WiFi channels overlap with each other, signal fluctuations can also be detected at the center frequencies of the left and right adjacent channels of the channel currently occupied by communication. Binarization is performed on the sorted volatility coefficients according to the mean value of the volatility coefficients, and if it is greater than the mean value of the volatility coefficients, the binarization is 1; if it is smaller than the mean value of the volatility coefficients, the binarization is 0.

By binarizing the fluctuation degree coefficient, it can be converted into a form that the computer can easily identify the size relationship, which is convenient for identification and judgment.

Among them, the obtained fluctuation degree coefficient is used to measure the fluctuation of the signal in the channel within the sampling time. After evaluating the signal strengths of all channels, a histogram as shown in Figure 5 will be obtained that expresses the distribution of signal fluctuations. The histogram is binarized by taking the average value as a threshold, and finally a binarization table for judging the strength of each channel signal is obtained as a binarization sequence of fluctuation degree coefficients. The binarization sequence of the fluctuation degree coefficient is shown in FIG. 6 , the channel fluctuation degree coefficient with the serial number of 5/6/7 is binarized to 1, and the rest are 0.

S530: Determine the occupied Wi-Fi channel according to the binarization sequence of the fluctuation degree coefficient.

If an available Wi-Fi channel is occupied, its adjacent available Wi-Fi channel will also have strong signal strength. Based on this, if the binarization of several consecutive serial numbers is 1, the occupied Wi-Fi The Fi channel is likely to be one of them. In this way, the occupied Wi-Fi channel can be determined.

In this way, through sorting and binarization, an easily identifiable binarized sequence of fluctuation degree coefficients can be obtained, so that the occupied Wi-Fi channel can be easily determined; it is simple, convenient, and requires low computing power.

In this way, in the sampling process, the sampling duration of each channel is set to be the same, and the sampling rate of the ADC is kept consistent. After sampling of each channel, a signal strength sequence with the same number of points will be obtained. The absolute value of the difference is averaged for this sequence, and the noise whose result is less than a certain threshold is filtered out during the process of difference, so as to eliminate the influence of ADC noise.

Preferably, as shown in FIG. 7 , in S510, a signal fluctuation degree coefficient is determined according to the AD sampling result;

S511, obtaining a first threshold;

Wherein, the first threshold may be determined according to experiments, or may be determined according to actual conditions. Alternatively, a certain Wi-Fi channel can be selected first, then multiple AD sampling results thereof can be obtained, and the selection of the first threshold can be comprehensively judged according to the multiple AD sampling results, so that the value of the first threshold can make the final threshold. Judgments get the most accurate results.

S512: Calculate the fluctuation degree coefficient according to the first threshold and the AD sampling result.

Through the first threshold, the noise whose difference result is smaller than the first threshold is filtered out, so as to eliminate the influence of ADC noise.

Preferably, the calculation formula of the fluctuation degree coefficient is:

Wherein, F is the fluctuation degree coefficient, x _k , x _k+1 are the sampling values in the AD sampling result, k is the serial number of the sampling values, and n is the total number of sampling values.

In this way, the fluctuation degree coefficient can be directly calculated, and the magnitude of the sampled signal strength can be directly reflected by this parameter; the larger the fluctuation degree coefficient, the greater the signal strength.

Among them, define the function δ:

The threshold is a first threshold, and the value of the first threshold is determined according to the actual situation or preset.

With this function, noise whose result is less than a certain threshold can be filtered out to remove the effect of ADC noise.

Preferably, as shown in FIG. 8, S530, determining the occupied Wi-Fi channel according to the binarization sequence of the fluctuation degree coefficient, including:

S531, obtaining the binarized templates of all the available Wi-Fi channels;

Taking Wi-Fi working under the 802.11g protocol as an example, the channels open to use in China are 1-13, which are evenly distributed in the 2412MHz-2472MHz frequency band, the center frequency of the channels is 5MHz apart, and the frequency ranges covered by each channel overlap each other. Except for channel 1 and channel 13 in the histogram obtained by the above detection method, signal fluctuations higher than average will be obtained at the center frequency of the current communication channel and the center frequencies of adjacent channels on both sides. Taking channel 6 as an example, under normal circumstances, the result of binarizing the histogram is shown in Fig. 6 . The binarization templates of other channels can be deduced in turn. Similarly, for edge channels 1 and 13, taking channel 1 as an example, the result of the histogram binarization (binarization template) is as shown in FIG. 9 .

It should be noted here that in the example channels 1-13, the channel center frequencies are separated by 5MHz, so the center frequency of the current communication channel and the center frequencies of the adjacent channels on both sides will obtain a signal fluctuation degree coefficient higher than the average value, and also That is, three consecutive sequence numbers in the binarization template are all 1 (the channels at both ends are both consecutive two sequence numbers are 1).

S532 , if the binarization sequence of the fluctuation degree coefficient matches the binarization template, determine that the Wi-Fi signal occupied by the Wi-Fi signal is the Wi-Fi channel corresponding to the binarization template.

If the channel 6 in the example is the same as the binarization sequence of the fluctuation degree coefficient, the Wi-Fi channel is determined to be the channel 6.

It should be noted here that matching the binarization sequence of the fluctuation degree coefficient with the binarization template is essentially judging whether there are three consecutive serial numbers that are all 1 (the channels at both ends are two consecutive serial numbers). In the case of 1), the matching is essentially that there are three consecutive serial numbers of 1 (the channels at both ends are two consecutive serial numbers of 1); therefore, the binary value of the channel corresponding to the middle serial number of the three consecutive serial numbers template matching.

Therefore, steps S531-S532 can also be described as: judging whether there are three consecutive sequence numbers of 1 in the binarization sequence of the fluctuation degree coefficient (the channels at both ends are the case where two consecutive sequence numbers are 1). , the channel corresponding to the middle sequence number of the three consecutive sequence numbers (the top sequence number of the two consecutive sequence numbers at both ends) is the occupied Wi-Fi channel.

Preferably, if the binarization sequence of the fluctuation degree coefficient does not match the binarization template, select some channels for re-sampling; until the binarization sequence of the fluctuation degree coefficient matches one of the two The valued template matches or the number of loops reaches the threshold.

That is to say, if the binarization sequence of the fluctuation degree coefficient does not have three consecutive serial numbers of 1 (the channels at both ends have two consecutive serial numbers of 1), it is judged that during the entire sampling process If there is an error, re-sample and calculate the available Wi-Fi channel that may have an excessive error, and then make a judgment again; if it still does not meet the requirements, continue to cycle until the above conditions are met or the number of cycles reaches the threshold.

If the cycle reaches the threshold, it is determined that there is a hardware connection problem.

Among them, the selection criteria of the re-sampled channel are taken as an example for the case of 1-13 channels with three consecutive serial numbers of 1 (the channels at both ends are two consecutive serial numbers of 1):

If only 1 channel detection result is higher than the average then:

If the channel is channel 1, resample channel 1 and channel 2; if the channel is channel 13, resample channel 12 and channel 13; for other channels, resample this channel and the channels on both sides.

If there are two consecutive channel detection results above average:

If the two channels are channels 1 and 2 respectively, the currently occupied channel is channel 1; if the two channels are channels 12 and 13, respectively, the currently occupied channel is channel 13; Channel resampling on both sides of two consecutive channels.

If the detection results of 3 consecutive channels are higher than the average value: select the middle channel as the final result.

If there are 4 consecutive channels with higher than average detection results: Resample these 4 channels.

If there are 5 or more consecutive channel sampling results that are higher than the average value: It is determined that there is a hardware connection problem.

If the detected result contains multiple groups of consecutive channels that are higher than the average value: adopt the above strategy for each group of consecutive channels.

If a new round of sampling according to the above rules still cannot draw a conclusion, it will resample according to the above rules on the basis of the latest sampling results. The upper limit of the number of nesting is n (n is a natural number greater than 2). This parameter can be set in Program internal settings. If the upper limit is exceeded, it is determined that there is a hardware connection problem and the channel detection program is exited.

Through this resampling, the problem that the judgment result is affected by the excessive error can be solved, so that the occupied Wi-Fi channel can be accurately judged.

It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Each embodiment in this application is described in a related manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. For related matters, please refer to some descriptions of the foregoing embodiments.

Although the present invention is disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be based on the scope defined by the claims.

Claims (10)

1. A Wi-Fi channel detection system, comprising:

the phase-locked loop circuit outputs at least one local oscillator signal with set frequency in a time-sharing manner under the control of the microcontroller; the mixer circuit mixes the local oscillator signal with an input Wi-Fi signal to obtain an intermediate frequency signal; the low-pass filter filters the intermediate frequency signal; the microcontroller is provided with an A/D converter which samples the filtered intermediate frequency signal; and the microcontroller determines a Wi-Fi channel occupied by the Wi-Fi signal according to the AD sampling result corresponding to different phase-locked loop frequency settings.

2. The Wi-Fi channel detection system of claim 1, further comprising:

the input end of the radio frequency single-pole double-throw switch is connected with the mixer circuit, one output end of the radio frequency single-pole double-throw switch is connected with the low-pass filter, and the other output end of the radio frequency single-pole double-throw switch is used as the output end of a system; and the microcontroller controls the radio frequency single-pole double-throw switch to conduct the frequency mixer circuit and the low-pass filter when a Wi-Fi channel is detected, and conducts the frequency mixer circuit and the output end of the system after the Wi-Fi channel occupied by the Wi-Fi signal is determined.

3. The Wi-Fi channel detection system of claim 1 or claim 2, wherein the microcontroller controls the local oscillator signal frequency output by the phase-locked loop circuit via a three-wire serial interface.

4. A Wi-Fi channel detection method based on the Wi-Fi channel detection system of any one of claims 1-3, comprising:

the method comprises the steps that a microcontroller acquires the center frequency of an available Wi-Fi channel;

the microcontroller controls a local oscillation signal output by the phase-locked loop circuit, so that the frequency of the local oscillation signal is the same as the central frequency;

the microcontroller reads an AD sampling result which is output by the A/D converter and corresponds to the central frequency;

the microcontroller controls a phase-locked loop to traverse and output local oscillator signals of the center frequency of all the available Wi-Fi channels, and a corresponding AD sampling result is obtained;

and determining the occupied Wi-Fi channels according to the AD sampling results corresponding to all the available Wi-Fi channels.

5. The Wi-Fi channel detection method of claim 4, wherein the microcontroller controls the rf single-pole double-throw switch to turn on the mixer circuit and the low-pass filter during Wi-Fi channel detection; and after the Wi-Fi channel occupied by the Wi-Fi signal is determined, the output ends of the mixer circuit and the system are conducted.

6. The Wi-Fi channel detection method of claim 4, wherein an AD sampling frequency and a sampling duration of the AD sampling result corresponding to each of the available Wi-Fi channels are the same.

7. The Wi-Fi channel detection method according to any one of claims 4-6, wherein the determining an occupied Wi-Fi channel based on AD sampling results corresponding to all of the available Wi-Fi channels comprises:

determining a signal fluctuation degree coefficient according to the AD sampling result;

sequencing the fluctuation degree coefficients of the available Wi-Fi channels according to the frequency band range of the available Wi-Fi channels;

carrying out binarization on the sorted fluctuation degree coefficients according to the average value of the fluctuation degree coefficients to obtain a binarization sequence of the fluctuation degree coefficients;

and determining the occupied Wi-Fi channel according to the binarization sequence of the fluctuation degree coefficient.

8. The Wi-Fi channel detection method of claim 7, wherein determining a signal fluctuation degree coefficient from the AD sampling result comprises:

acquiring a first threshold value;

and calculating the fluctuation degree coefficient according to the first threshold and the AD sampling result.

9. The Wi-Fi channel detection method of claim 8, wherein the fluctuation degree coefficient is calculated by:

wherein F is the coefficient of fluctuation degree, x_k，x_k+1And k is a serial number of the sampling value, and n is the total number of the sampling value in the AD sampling result.

10. The Wi-Fi channel detection method of claim 7, wherein determining an occupied Wi-Fi channel based on the binarization sequence of the fluctuation degree coefficient comprises:

acquiring binarization templates of all the available Wi-Fi channels;

and if the binarization sequence of the fluctuation degree coefficient is matched with the binarization template, determining that the Wi-Fi signal occupies the Wi-Fi channel corresponding to the binarization template.

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