A Phase Offset Detection Method for Precision Motion Recognizers in Wireless Local Area Networks

Abstract

The present invention provides a system and method for offset detection of a precise motion recognizer in a wireless local area network, belonging to the technical field of indoor motion recognition. By constructing the channel state environment of the wireless local area network, a channel emulator processes the test signal, a radio frequency stirrer performs reflection processing on the processed test signal, a variable resistor load adjusts the amplitude information of the reflected test signal, and then returns it to the channel emulator. The channel emulator resolves the returned test signal to obtain phase change information. The phase change information is input into the formula of the phase joint probability density to judge the phase offset degree, and the offset detection of the device to be detected is carried out according to the phase offset degree. The present invention can greatly reduce the reflection recovery time, achieve the effect of rapid attenuation, can distinguish more signal peaks, improve the phase information resolution from the side, has stronger compatibility and high measurement accuracy, and the method design is reasonable and reliable.

Description

Technical Field

[0001] The present invention relates to the field of indoor motion recognition, and particularly to an offset detection system and method for a precision motion recognizer in a wireless local area network. Background Art

[0002] To meet the daily communication needs, there are generally a large number of network connection devices in the indoor environment, such as WIFI transceivers, Bluetooth transceivers, micro base stations, and intelligent networked sensors. These devices are not only used for communication and Internet access, but also for indoor positioning; with the development of the industry, the signal processing accuracy of the devices has been continuously improved, gradually supporting behavior recognition (fall detection), respiration perception, and sleep heartbeat / eye movement monitoring. Devices that use wireless signals (such as WiFi signals) in the local area network for personnel motion perception and recognition have also started the commercialization process.

[0003] However, the main parameters of the existing detection and motion recognition using WIFI and Bluetooth devices are very different. Measuring only relevant parameters such as signal power and frequency is not sufficient to determine whether the measured object meets its own characteristic measurement values and qualification criteria, and it is even more impossible to confirm whether its main measurement values have changed. Summary of the Invention

[0004] In view of the above technical problems existing in the prior art, an offset detection system and method for a precision motion recognizer in a wireless local area network are provided. By constructing the channel state environment of the wireless local area network, the channel emulator processes the test signal, the RF stirrer performs reflection processing on the processed test signal, the variable resistor load adjusts the amplitude information of the reflected test signal, and then returns it to the channel emulator; the channel emulator calculates the returned test signal to obtain the phase change information. The phase change information is input into the formula of the phase joint probability density to judge the degree of phase offset, and the offset detection of the device to be detected is performed according to the degree of phase offset; the present invention can greatly reduce the reflection recovery time, achieve the effect of rapid attenuation, can distinguish more signal peaks, improve the phase information resolution from the side, has stronger compatibility and high measurement accuracy, and the method design is reasonable and reliable.

[0005] The present invention provides an offset detection system for a precision motion recognizer in a wireless local area network, including a device under test (DUT), a channel emulator, an RF stirrer, a variable resistor load, and a circulator; the device under test is connected to the channel emulator, and the RF stirrer and the variable resistor load are connected to the channel emulator through the circulator; the channel emulator establishes a channel state environment; the RF stirrer and the variable resistor load simulate the interference signals of the transmission channel; wherein, the device under test is a precision motion recognizer.

[0006] Preferably, the RF stirrer includes a reflection mode or a through mode; wherein, the RF stirrer adopts different modes at different times.

[0007] Preferably, the device under test includes at least a pair of antennas for transmitting and receiving RF signals.

[0008] Preferably, the variable resistance load simulates different RF loads according to the change of the test signal.

[0009] The present invention provides a method for detecting the offset of a precision motion identifier in a wireless local area network. According to the offset detection system described above, the offset detection of the precision motion identifier is carried out. The offset detection method includes the following steps:

[0010] The device under test sends a test signal to the channel emulator;

[0011] The offset detection is carried out in the channel state environment, including the following steps:

[0012] The channel emulator processes the test signal and then sends the processed test signal to the RF stirrer;

[0013] The RF stirrer performs reflection processing on the processed test signal, changing the amplitude information and phase information of the processed test signal;

[0014] The variable resistance load adjusts the amplitude information of the test signal after reflection processing and then returns the adjusted test signal to the channel emulator;

[0015] The channel emulator resolves the returned test signal to obtain time domain information, and the time domain information includes phase change information

[0016] The phase change information is input into the formula of the phase joint probability density Based on the formula of the phase joint probability density the degree of phase offset is judged, and the offset detection of the device under test is carried out according to the degree of phase offset.

[0017] Preferably, the processing of the test signal specifically includes: performing frequency offset, frequency loss and time delay addition on the test signal.

[0018] Preferably, the channel emulator also measures the test signal, obtains the pulse signal and channel gain matrix of the test signal, and stores the pulse signal and channel gain matrix.

[0019] Preferably, the channel state environment includes: obtaining the channel state environment by labeling different channel gain matrices, and the different channel gain matrices are stored in the channel emulator.

[0020] Preferably, the channel state environment is specifically: the radio frequency conditions identical to the indoor space environment where the wireless local area network is located.

[0021] Preferably, the pulse signal is specifically: the pulse signal of the test signal during the signal acquisition time period.

[0022] Preferably, a test signal model within the signal acquisition time period is set, and the model is as follows:

[0023]

[0024] where i is the i-th moment within the signal acquisition time period, x i is the decoded symbol data, s i is the system transmitted symbol data, w i is Gaussian white noise with a mean of zero and a variance of 2σ 2 and K is the observation data length.

[0025] Preferably, the phase change information has the following formula:

[0026]

[0027] where d is the action path length when time is invariant, Δd represents the additional path length caused by simulating human behavior, h i represents the complex attenuation of the path, and λ represents the wavelength of the test signal.

[0028] Preferably, the phase joint probability density has the following formula:

[0029]

[0030] where j is the imaginary unit.

[0031] Preferably, the channel emulator resolves the returned test signal, specifically including: the channel emulator resolves the channel gain matrix to obtain the symbol data change information in the time domain of each subcarrier.

[0032] Preferably, the symbol data change information includes amplitude change information and phase change information

[0033] Preferably, during the offset detection process, the time domain information of the test signal transmission path has been calibrated, and the calibration data is within the preset validity period.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. A method and system for offset detection of a precision motion identifier in a wireless local area network according to the present invention. By constructing the channel state environment of the wireless local area network, a channel emulator processes the test signal, a radio frequency stirrer performs reflection processing on the processed test signal, a variable resistor load adjusts the amplitude information of the reflected test signal, and then returns it to the channel emulator; the channel emulator resolves the returned test signal to obtain phase change information The phase change information is input into the formula of the phase joint probability density to judge the degree of phase offset, and the offset detection of the device to be detected is carried out according to the degree of phase offset; the present invention can greatly reduce the reflection recovery time, achieve the effect of rapid attenuation, can distinguish more signal peaks, improve the phase information resolution from the side, has stronger compatibility and high measurement accuracy, and the method design is reasonable and reliable.

[0036] 2. A method and system for offset detection of a precision motion identifier in a wireless local area network according to the present invention. The phase change information is input into the formula of the phase joint probability density to judge the degree of phase offset, that is, the probability density is used to judge the degree of phase offset, without calculating each specific offset value, saving computing power and improving the detection efficiency.

[0037] 3. A method and system for offset detection of a precision motion identifier in a wireless local area network according to the present invention. The variable resistor load simulates different radio frequency loads according to the change of the test signal, optimizes the shadow effect of the channel state environment, couples the test signal after end attenuation, and resolves the returned test signal to obtain time domain information; it can greatly reduce the reflection recovery time to achieve the effect of rapid attenuation and distinguish more signal peaks.

[0038] 4. A method and system for offset detection of a precision motion identifier in a wireless local area network according to the present invention. The channel state environment includes: the channel state environment obtained by labeling different channel gain matrices; there is no need to detect in an actual specific site, and the required channel state can be designed according to the customer's usage scenario, with wider applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a flowchart of a system for offset detection of a precision motion identifier in a wireless local area network according to an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of a method for offset detection of a precision motion identifier in a wireless local area network according to an embodiment of the present invention;

[0041] Figure 3It is a schematic diagram of the action perception signal processing and optimization of an offset detection system for a precision motion identifier in a wireless local area network according to an embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of the waveform of the DUT test signal after normalization in an offset detection system for a precision motion identifier in a wireless local area network according to an embodiment of the present invention. Specific embodiments

[0043] The following combines the attached Figures 1-4 , and details the specific embodiments of a method and system for offset detection of a precision motion identifier in a wireless local area network of the present invention.

[0044] Embodiment 1

[0045] According to a specific implementation scheme of the present invention, the offset detection system for a precision motion identifier in a wireless local area network of the present invention will be described in detail below.

[0046] As Figure 1 shown, the present invention provides an offset detection system for a precision motion identifier in a wireless local area network, including a device under test, a channel emulator, a radio frequency stirrer, a variable resistor load, and a circulator; the device under test is connected to the channel emulator, and the radio frequency stirrer and the variable resistor load are connected to the channel emulator through the circulator; the channel emulator establishes a channel state environment; the radio frequency stirrer and the variable resistor load simulate interference signals of the transmission channel; wherein, the device under test is a precision motion identifier, and the variable resistor load simulates different radio frequency loads according to the change of the test signal.

[0047] When the radio frequency stirrer is not turned on and the reflection remains in the through state, the waveform of the test signal directly stored in the channel emulator after normalization is as Figure 4 shown, and the time-domain information obtained by solving the channel gain matrix is shown in Figure 3 Signal 1, and at this time, the waveform fineness is difficult to meet the requirements for detecting the device under test with high precision;

[0048] At this time, if the variable resistor load is combined, and the corresponding radio frequency load is simulated according to the magnitude of the passed test signal for shadow effect optimization, and the test signal is coupled after tail-end attenuation, the time-domain information obtained by solving the returned test signal is shown in Figure 2 Signal 2 (Signal 3 is the theoretical waveform), which can greatly reduce the reflection recovery time to achieve the effect of rapid attenuation, can distinguish more signal peaks, and at the same time improve the phase information resolution from the side.

[0049] Embodiment 2

[0050] As Figure 2As shown, according to a specific embodiment of the present invention, a method for offset detection of a precision motion identifier in a wireless local area network of the present invention will be described in detail below.

[0051] The present invention provides a method for offset detection of a precision motion identifier in a wireless local area network, comprising the following steps:

[0052] The device to be detected sends a test signal to the channel emulator;

[0053] Offset detection is performed in the channel state environment established by the channel emulator, including the following steps:

[0054] The channel emulator processes the test signal for frequency offset, frequency loss, and delay addition, and then sends the processed test signal to the RF stirrer;

[0055] The RF stirrer performs reflection processing on the processed test signal, changing the amplitude information and phase information of the processed test signal;

[0056] The variable resistance load adjusts the amplitude information of the reflected processed test signal, and then returns the adjusted test signal to the channel emulator;

[0057] The channel emulator calculates the channel gain matrix of the returned test signal to obtain the amplitude change information and phase change information of each subcarrier in the time domain

[0058] The phase change information is input into the formula of the joint probability density of the phase Based on the formula of the joint probability density of the phase the degree of phase offset is judged, and the offset detection of the device to be detected is performed according to the degree of phase offset.

[0059] Among them, a test signal model within the signal acquisition time period is set, and the model is as follows:

[0060]

[0061] where i is the i-th moment within the signal acquisition time period, x i is the decoded symbol data, s i is the system transmitted symbol data, w i is Gaussian white noise with a mean of zero and a variance of 2σ 2 and K is the length of the observed data.

[0062] The formula for the phase change information is as follows:

[0063]

[0064] Among them, d is the action path length when time is invariant, Δd represents the additional path length caused by simulating human behavior, and h i represents the complex attenuation of the path, and λ represents the wavelength of the test signal.

[0065] Phase joint probability density The formula is as follows:

[0066]

[0067] Among them, j is the imaginary unit.

[0068] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for detecting phase offset of a precision motion identifier in a wireless local area network, characterized in that, The phase offset detection of the precision motion identifier is performed using the following phase offset detection system. The phase offset detection system of the precision motion identifier in a wireless local area network includes a device under test, a channel emulator, a radio frequency stirrer, a variable resistor load, and a circulator. The device under test is connected to the channel emulator, and the radio frequency stirrer and the variable resistor load are connected to the channel emulator through the circulator. The channel emulator establishes a channel state environment. The radio frequency stirrer and the variable resistor load simulate the interference signals of the transmission channel. Among them, the device under test is a precision motion identifier. It includes the following steps: The device under test sends a test signal to the channel emulator. Phase offset detection is performed in the channel state environment, including the following steps: The channel emulator processes the test signal and then sends the processed test signal to the radio frequency stirrer. The radio frequency stirrer performs reflection processing on the processed test signal, changing the amplitude information and phase information of the processed test signal. The variable resistor load adjusts the amplitude information of the reflected processed test signal and then returns the adjusted test signal to the channel emulator. The channel emulator also measures the test signal, obtains the pulse signal and channel gain matrix of the test signal, and stores the pulse signal and channel gain matrix; the pulse signal is specifically: the pulse signal of the test signal during the signal acquisition time period. The channel emulator resolves the returned test signal to obtain time-domain information, and the time-domain information includes phase change information ; Input the phase change information into the formula of the input phase joint probability density to judge the phase offset degree based on the formula of the phase joint probability density and perform the phase offset detection of the device to be tested according to the phase offset degree. Specifically: Set the test signal model within the signal acquisition time period, and the model is as follows: x i =s i e jφ +w i ， i =0,1,…,K-1， Among them, i is the i th moment within the signal acquisition time period, x i is the decoded symbol data, s i is the system transmitted symbol data, w i is Gaussian white noise with a mean of zero and a variance of 2σ 2 ; K is the observation data length; The phase change information has the following formula: ， Among them, d is the action path length when the time is invariant, represents the additional path length caused by simulating the behavior of personnel, represents the complex attenuation of the path, and λ represents the wavelength of the test signal; The phase joint probability density ； wherein, j is the imaginary unit.

2. The method for detecting phase offset of a precision motion identifier in a wireless local area network according to claim 1, characterized in that, The processing of the test signal specifically includes: performing frequency offset, frequency loss, and delay addition on the test signal.

3. The method for detecting phase offset of a precision motion identifier in a wireless local area network according to claim 1, characterized in that, The channel state environment includes: obtaining the channel state environment by labeling different channel gain matrices, and the different channel gain matrices are stored in the channel emulator.

4. The method for detecting phase offset of a precision motion identifier in a wireless local area network according to claim 3, characterized in that, The channel state environment is specifically: the radio frequency conditions the same as the indoor space environment where the wireless local area network is located.

5. The method for detecting phase offset of a precision motion identifier in a wireless local area network according to claim 1, characterized in that, The channel emulator performs calculation on the returned test signal, specifically including: the channel emulator performs calculation on the channel gain matrix to obtain the symbol data change information of each subcarrier in the time domain.

6. The method for detecting phase offset of a precision motion identifier in a wireless local area network according to claim 5, characterized in that, The symbol data change information includes amplitude change information and phase change information .

7. The phase offset detection method of the precision motion identifier in a wireless local area network according to claim 1, wherein During the phase offset detection process, the time domain information of the test signal transmission path has been calibrated, and the calibration data is within the preset validity period.

8. The phase offset detection method of the precision motion identifier in a wireless local area network according to claim 1, wherein The radio frequency stirrer includes a reflection mode or a through mode; among them, the radio frequency stirrer adopts different modes at different times.

9. The phase offset detection method of the precision motion identifier in a wireless local area network according to claim 1, wherein The device under test includes at least a pair of antennas for transmitting and receiving radio frequency signals.

10. The phase offset detection method of the precision motion identifier in a wireless local area network according to claim 1, wherein The variable resistor load simulates different radio frequency loads according to the change of the test signal.

Images