Channel estimation-based tracking method, electronic device, and storage medium

Abstract

This application provides a channel estimation-based tracking method, electronic device, and storage medium. The method includes: cleaning the channel estimation information corresponding to each antenna element to obtain the target channel estimation result for each antenna element; selecting the smallest non-zero frequency domain channel estimation value from the target channel estimation results of the target antenna element as a first adjustment coefficient; amplifying the first adjustment coefficient according to a preset amplification factor to obtain a second adjustment coefficient; adjusting the target channel estimation result of the target antenna element using the first adjustment coefficient to obtain a first channel estimation result; adjusting the target channel estimation result of the antenna element under a specified receiver using the second adjustment coefficient to obtain a second channel estimation result; determining a specified channel estimation result using the first channel estimation result and the second channel estimation result; and tracking a passive target based on the specified channel estimation result of each antenna element. This application achieves accurate tracking of passive targets.

Description

Technical Field

[0001] This application relates to the field of wireless positioning technology, and in particular to a tracking method based on channel estimation, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Passive targets (people or other targets without terminal devices) can affect indoor Wi-Fi signals as they move within an indoor environment, causing changes in multipath channels. Based on this principle, passive targets can be tracked and located indoors, and this type of tracking scheme has broad application prospects in many indoor scenarios. Summary of the Invention

[0003] The purpose of this application is to provide a channel estimation-based tracking method, electronic device, and storage medium for accurate tracking and positioning of passive targets.

[0004] On one hand, this application provides a channel estimation-based tracking method applied to a Wi-Fi transceiver system, the Wi-Fi transceiver system including a transmitter, a first receiver, and a second receiver, the first receiver including at least one antenna element, and the second receiver including at least two antenna elements, the method including:

[0005] For the channel estimation information corresponding to each antenna element, periodic cleaning is performed to obtain the target channel estimation result corresponding to each antenna element; wherein, the target channel estimation result includes the frequency domain channel estimation values ​​of multiple symbols on multiple subcarriers in the current period;

[0006] Each receiver is designated as a target receiver, and each antenna element under the target receiver is designated as a target antenna element.

[0007] From the target channel estimation results of the target antenna array elements, the smallest non-zero frequency domain channel estimation value is selected as the first adjustment coefficient;

[0008] The first adjustment coefficient is processed according to the preset amplification factor to obtain the second adjustment coefficient;

[0009] The target channel estimation result of the target antenna array element is adjusted by the first adjustment coefficient to obtain the first channel estimation result;

[0010] The target channel estimation result of the antenna array element under the specified receiver is adjusted by the second adjustment coefficient to obtain the second channel estimation result; wherein, the specified receiver is a receiver other than the target receiver;

[0011] The first channel estimation result and the second channel estimation result are multiplied by conjugate to obtain the specified channel estimation result of the target antenna array element;

[0012] The passive target is tracked based on the specified channel estimation result corresponding to each antenna element.

[0013] In one embodiment, the step of periodically cleaning the channel estimation information corresponding to each antenna element to obtain the target channel estimation result for each antenna element includes:

[0014] For each antenna array element, the frequency domain channel estimation values ​​of multiple symbols on a first specified number of subcarriers are extracted to obtain the extracted channel estimation information.

[0015] The extracted channel estimation information is transformed into time-domain channel estimation information by inverse Fourier transform, and the power of each channel is determined based on the time-domain channel estimation information.

[0016] The window is divided into multiple channels with the highest power according to the preset window length, and the average power of the corresponding channels outside the window is calculated as the noise power.

[0017] Several in-window channels with power greater than a threshold power are selected from multiple in-window channels, and the in-window channel with the highest power is filtered out from the selected in-window channels. The target time-domain channel estimation information is determined based on the filtered in-window channels; wherein, the threshold power is determined by the noise power and a preset third adjustment coefficient.

[0018] The target time-domain channel estimation information of each antenna element is subjected to Fourier transform to obtain the target channel estimation result of each antenna element in the frequency domain.

[0019] In one embodiment, before converting the extracted channel estimation information into time-domain channel estimation information through inverse Fourier transform, the method further includes:

[0020] The number of subcarriers in the extracted channel estimation information is expanded to a second specified number by the boundary repetition method;

[0021] Perform a circular displacement operation on the expanded extracted channel estimation information.

[0022] In one embodiment, determining the target time-domain channel estimation information based on the filtered in-window channels includes:

[0023] Based on the time-domain channel estimates of the filtered in-window channels, intermediate time-domain channel estimation information is constructed.

[0024] The intermediate time-domain channel estimation information is padded with zeros to obtain the target time-domain channel estimation information; wherein, the target time-domain channel estimation information includes time-domain channel estimation values ​​corresponding to a third specified number of channels.

[0025] In one embodiment, performing Fourier transform on the target time-domain channel estimation information of each antenna element to obtain the target channel estimation result of each antenna element in the frequency domain includes:

[0026] The target time-domain channel estimation information of each antenna element is subjected to Fourier transform to obtain the intermediate channel estimation result of each antenna element in the frequency domain.

[0027] Perform a circular displacement operation on each intermediate channel estimation result, and sample the intermediate channel estimation results after the circular displacement operation to obtain the target channel estimation result for each antenna element.

[0028] In one embodiment, the designated receiver includes at least two antenna array elements;

[0029] The step of adjusting the target channel estimation result of the antenna array element under the specified receiver with the second adjustment coefficient to obtain the second channel estimation result includes:

[0030] The target channel estimation results of at least two antenna elements under the specified receiver are adjusted by the second adjustment coefficient to obtain the adjusted channel estimation result of each antenna element.

[0031] The adjusted channel estimation results of at least two antenna elements under the specified receiver are averaged to obtain the second channel estimation result.

[0032] In one embodiment, tracking the passive target based on the specified channel estimation result corresponding to each antenna element includes:

[0033] Based on the specified channel estimation results of several antenna array elements under each receiver, an average channel estimation result corresponding to each receiver is generated, and a covariance matrix corresponding to the average channel estimation result is generated to obtain the covariance matrix corresponding to each receiver.

[0034] The covariance matrix of the first receiver is decomposed by eigenvalue to obtain the first observed Doppler velocity of the passive target relative to the first receiver, and the covariance matrix of the second receiver is decomposed by eigenvalue to obtain the second observed Doppler velocity of the passive target relative to the second receiver.

[0035] Based on the specified channel estimation results of at least two antenna elements of the second receiver, a three-dimensional tensor corresponding to the second receiver is constructed, and a two-dimensional matrix corresponding to the current period is decomposed from the three-dimensional tensor.

[0036] The covariance matrix of the two-dimensional matrix is ​​generated as the angle of arrival covariance matrix, and the angle of arrival covariance matrix is ​​decomposed by eigenvalue to obtain the angle of arrival of the passive target relative to the second receiver in the current period.

[0037] The passive target is tracked in a target coordinate system based on the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival; wherein the target coordinate system is determined by the first position information of the first receiver and the second position information of the second receiver.

[0038] In one embodiment, tracking the passive target in the target coordinate system based on the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival includes:

[0039] The target movement speed of the passive target is determined based on the first observed Doppler velocity and the second observed Doppler velocity.

[0040] The movement path of the passive target is determined based on the target's movement speed and cycle duration; wherein the movement path represents the movement direction and movement distance of the passive target.

[0041] The passive target is tracked based on the movement path, the angle of arrival, and the angle of arrival of the previous cycle.

[0042] On the other hand, this application provides an electronic device, the electronic device comprising:

[0043] processor;

[0044] Memory used to store processor-executable instructions;

[0045] The processor is configured to execute the channel estimation-based tracking method described above.

[0046] Furthermore, this application provides a computer-readable storage medium storing a computer program that can be executed by a processor to perform the aforementioned channel estimation-based tracking method.

[0047] The proposed solution, by cleaning the channel estimation information of each antenna element in the Wi-Fi transceiver system and removing noise and LOS (Line of Sight) background, can amplify the impact of passive target movement on channel state information, obtain the specified channel estimation results corresponding to each antenna element, and then accurately track the passive target using the specified channel estimation results of each antenna element. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below.

[0049] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0050] Figure 2 A schematic flowchart of a channel estimation-based tracking method provided in an embodiment of this application;

[0051] Figure 3 Provided for an embodiment of this application Figure 2 A detailed flowchart of step 210 is shown below;

[0052] Figure 4 This is a schematic diagram of the cleaning process for channel estimation information provided in an embodiment of this application;

[0053] Figure 5 Provided for an embodiment of this application Figure 2 A detailed flowchart of step 280 is provided.

[0054] Figure 6 A schematic diagram of the coordinate system of a three-dimensional tensor provided in an embodiment of this application;

[0055] Figure 7 A schematic diagram of speed fusion provided for an embodiment of this application;

[0056] Figure 8 A schematic diagram of target tracking provided for an embodiment of this application;

[0057] Figure 9 A block diagram of a channel estimation-based tracking device provided in an embodiment of this application. Detailed Implementation

[0058] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0059] Similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0060] like Figure 1 As shown, this embodiment provides an electronic device 1, including: at least one processor 11 and a memory 12. Figure 1 Taking a processor 11 as an example, the processor 11 and memory 12 are connected via a bus 10. The memory 12 stores instructions that can be executed by the processor 11. The instructions are executed by the processor 11 to enable the electronic device 1 to perform all or part of the processes of the methods described in the embodiments below. In one embodiment, the electronic device 1 may be a computing device in a Wi-Fi transceiver system, which may be a transmitter or receiver in the Wi-Fi transceiver system, or a device that interfaces with a transmitter or receiver, for performing a channel estimation-based tracking method.

[0061] The memory 12 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable red-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0062] This application also provides a computer-readable storage medium storing a computer program that can be executed by a processor 11 to perform the channel estimation-based tracking method provided in this application.

[0063] In an indoor environment, the transmitter, first receiver, and second receiver in a Wi-Fi transceiver system can be placed at designated locations within the indoor scene (e.g., in a living room, the transmitter can be placed in the upper left corner, the first receiver in the upper right corner, and the second receiver in the lower left corner). During the process of the transmitter sending Wi-Fi signals and the first and second receivers receiving them, the electronic devices can obtain channel state information (CSI) through channel estimation. Because various objects (such as people, furniture, appliances, and pets) exist in the indoor scene, Wi-Fi signals will exhibit various reflections; therefore, multiple wireless channels exist between the transmitter and receiver. When a passive target moves within the scene, since the position of stationary objects remains unchanged, the CSI can characterize the impact of the passive target's movement on the wireless channels. Therefore, the CSI can be used to track passive targets in the indoor scene.

[0064] See Figure 2 This is a flowchart illustrating a channel estimation-based tracking method provided in an embodiment of this application. Figure 2 As shown, the method may include steps 210-280.

[0065] Step 210: Perform periodic cleaning on the channel estimation information corresponding to each antenna element to obtain the target channel estimation result for each antenna element; wherein, the target channel estimation result includes the frequency domain channel estimation values ​​of multiple symbols on multiple subcarriers in the current period.

[0066] This application relates to a Wi-Fi transceiver system, which includes a transmitter for transmitting Wi-Fi signals and a first receiver and a second receiver for receiving Wi-Fi signals. The first receiver includes at least one antenna element, and the second receiver includes at least two antenna elements, each capable of receiving the Wi-Fi signal transmitted from the transmitter. The at least two antenna elements of the second receiver can form a one-dimensional uniform linear array, with the spacing between the antenna elements being half a wavelength; alternatively, the at least two antenna elements can be other array configurations, such as a UPA (Uniform Planar Array), a sparse array, or a two-dimensional array.

[0067] During the transmission of Wi-Fi signals by the transmitter and the reception of Wi-Fi signals by the first and second receivers, the electronic device can acquire channel estimation information corresponding to each antenna element of the first and second receivers. For example, the electronic device can process the pilot signal of the Wi-Fi signal received by each antenna element based on the Least Squares (LS) algorithm to obtain channel estimation information in the frequency domain. During the transmission and reception of Wi-Fi signals in the Wi-Fi transceiver system, the electronic device can continuously acquire channel estimation information corresponding to each antenna element. The channel estimation information can include frequency domain channel estimation values ​​for multiple symbols on multiple subcarriers.

[0068] Electronic devices can periodically detect the location of passive targets in an indoor scene. Therefore, for the channel estimation information of each antenna element, the electronic device can periodically clean it to obtain the target channel estimation result corresponding to each antenna element. The target channel estimation result is the channel estimation result after cleaning and removing the LOS channel, including the frequency domain channel estimation values ​​of multiple symbols on multiple subcarriers in the current period. Here, the period duration can be configured as needed. For example, the period duration can be the interval between two data packets sent by the transmitter. Each data packet can include multiple symbols. In this case, the channel estimation result includes the frequency domain channel estimation values ​​of multiple symbols in the data packets sent in the current period on multiple subcarriers.

[0069] Step 220: Designate each receiver as a target receiver and each antenna element under the target receiver as a target antenna element.

[0070] The electronic device can designate each receiver as a target receiver and each antenna element under the target receiver as a target antenna element to execute the subsequent processing steps 230 to 270. The electronic device can designate the first receiver and the second receiver as target receivers sequentially. When the first receiver is designated as the target receiver, the second receiver can be designated as the target receiver. When the second receiver is designated as the target receiver, the first receiver can be designated as the target receiver.

[0071] Step 230: Select the smallest non-zero frequency domain channel estimate from the target channel estimation results of the target antenna array elements as the first adjustment coefficient.

[0072] After selecting any antenna element as the target antenna element, the electronic device can select the smallest non-zero frequency domain channel estimate from the frequency domain channel estimates of multiple symbols in multiple subcarriers included in the target channel estimation result of the target antenna element, and use it as the first adjustment coefficient.

[0073] For example, the target channel estimation result of the antenna array element of the first receiver can be denoted as: Here, k represents the subcarrier index and l represents the symbol index. The target channel estimation result includes k*l frequency domain channel estimates. The electronic device can select the smallest non-zero frequency domain channel estimate as the first adjustment coefficient γ.

[0074] Step 240: Process the first adjustment coefficient according to the preset amplification factor to obtain the second adjustment coefficient.

[0075] The magnification factor can amplify the first adjustment factor. The value of the magnification factor can be set as needed. For example, the magnification factor can be a few, hundreds, thousands, etc.

[0076] Electronic devices can multiply the amplification factor by the first adjustment factor to obtain the second adjustment factor β.

[0077] Step 250: Adjust the target channel estimation result of the target antenna array element with the first adjustment coefficient to obtain the first channel estimation result.

[0078] The first channel estimation result is the channel estimation result after adjusting the target channel estimation result of the target antenna array element by the first adjustment coefficient.

[0079] The electronic device can select non-zero frequency domain channel estimates from all frequency domain channel estimates of the target antenna array element, and subtract the first adjustment coefficient from each selected frequency domain channel estimate to obtain the first channel estimate result.

[0080] For example, the target channel estimation result of the antenna array element of the first receiver. The first channel estimation result is obtained by selecting multiple non-zero frequency domain channel estimates from k*l frequency domain channel estimates and subtracting the first adjustment coefficient from each of them.

[0081] This adjustment process can eliminate the phase-related biases in the target channel estimation results.

[0082] Step 260: Adjust the target channel estimation result of the antenna array element under the specified receiver with the second adjustment coefficient to obtain the second channel estimation result; wherein, the specified receiver is a receiver other than the target receiver.

[0083] The second channel estimation result is the target channel estimation result of the antenna array element under the specified receiver, and the channel estimation result after adjustment by the second adjustment coefficient.

[0084] For the target channel estimation result of each antenna element under a specified receiver, the electronic device can add the second adjustment coefficient to the frequency domain channel estimation values ​​of multiple symbols in multiple subcarriers in the target channel estimation result to obtain the second channel estimation result.

[0085] In one embodiment, the designated receiver includes at least two antenna array elements, for example, the designated receiver is a second receiver.

[0086] The electronic device can adjust the target channel estimation results of at least two antenna elements under a specified receiver by using the second adjustment factor. That is, the second adjustment factor is added to each frequency domain channel estimation value in each target channel estimation result to obtain the adjusted channel estimation result for each antenna element.

[0087] The electronic device can average the adjusted channel estimation results of at least two antenna elements under a specified receiver to obtain a second channel estimation result. During the averaging process, the average of the frequency domain channel estimates of the same symbol on the same subcarrier can be calculated among the adjusted channel estimation results of all antenna elements under the specified receiver.

[0088] Step 270: Multiply the first channel estimation result and the second channel estimation result by conjugate to obtain the specified channel estimation result of the target antenna array element.

[0089] After obtaining the first channel estimation result and the second channel estimation result, the first channel estimation result and the second channel estimation result can be multiplied by conjugate to obtain the specified channel estimation result of the target antenna array element. Here, the specified channel estimation result is the channel estimation result obtained by the aforementioned steps 230 to 270.

[0090] For example, the first receiver has an antenna element, and the target channel estimation result of the antenna element is denoted as... The second receiver has three antenna elements, and the target channel estimation results for the three antenna elements are denoted as follows:

[0091] When the first receiver is used as the target receiver and the antenna element of the first receiver is used as the target antenna element, it can be adjusted with the first adjustment factor. Adjusted separately using the second adjustment factor Then, the specified channel estimation result of the antenna array element of the first receiver is obtained by performing conjugate multiplication using the following formula (1):

[0092]

[0093] Among them, the target channel estimation results in formula (1) are all target channel estimation results adjusted by the first adjustment coefficient or the second adjustment coefficient; The target channel estimation results of the three antenna elements of the second receiver are averaged after adjustment.

[0094] By treating the first and second receivers as target receivers, and each antenna element under the target receiver as a target antenna element, the specified channel estimation results corresponding to each antenna element of the first and second receivers can be obtained through processing. After this processing, the impact of passive target movement on channel state information is amplified in the specified channel estimation results.

[0095] Step 280: Track the passive target based on the specified channel estimation result corresponding to each antenna element.

[0096] After obtaining the specified channel estimation results for each antenna element, the electronic device can track the passive target based on multiple specified channel estimation results, thereby determining the current position of the passive target in the indoor scene.

[0097] By taking the above measures, after cleaning the channel estimation information of each antenna element in the Wi-Fi transceiver system and removing noise and LOS background, the impact of passive target movement on channel state information can be amplified, and the specified channel estimation results corresponding to each antenna element can be obtained. Then, the specified channel estimation results of each antenna element can be used to accurately track the passive target.

[0098] In one embodiment, see Figure 3 This is provided as an embodiment of the present application. Figure 2 A detailed flowchart of step 210 is shown below. Figure 3 As shown, when performing step 210, steps 211 to 215 can be performed.

[0099] Step 211: For the channel estimation information corresponding to each antenna element, extract the frequency domain channel estimation values ​​of multiple symbols on a first specified number of subcarriers to obtain the extracted channel estimation information.

[0100] The first specified quantity can be pre-configured as needed, or it can be configured according to the hardware conditions of the electronic device. The first specified quantity can be denoted as K, for example, K is 60.

[0101] For each antenna element, the electronic device can extract the frequency domain channel estimate value of each symbol on a first specified number of subcarriers from the channel estimation information to obtain the extracted channel estimation information for that antenna element.

[0102] Step 212: Transform the extracted channel estimation information into time-domain channel estimation information through inverse Fourier transform, and determine the power corresponding to each channel based on the time-domain channel estimation information.

[0103] After obtaining the decimated channel estimation information, the electronic device can transform the decimated channel estimation information in the frequency domain to the time domain through the inverse Fast Fourier Transform to obtain the time-domain channel estimation information. This process can be represented by the following formula (2):

[0104]

[0105] in, This is time-domain channel estimation information; q represents the extracted channel estimation information; k represents the index of the receiver's antenna array elements; k represents the subcarrier index; and l represents the symbol index.

[0106] Based on the time-domain channel estimation information for each antenna element, the electronic device can calculate the power of the time-domain channel. The power calculation method can be expressed by the following formula (3):

[0107]

[0108] in, This represents the power of the l-th symbol of the q-th antenna element in the time-domain channel on the k-th subcarrier; This is the time-domain channel estimate of the l-th symbol of the q-th antenna element on the k-th subcarrier.

[0109] Step 213: Divide the channels with the highest power into multiple channels within the window according to the preset window length, and calculate the average power of the corresponding channels outside the window as the noise power.

[0110] The window length can be configured as needed. In one embodiment, the window length can be determined based on the cyclic prefix length. For example, the relationship between the window length L and the cyclic prefix length CP can be expressed as L ≤ 2 * CP - 1.

[0111] For any antenna element, after calculating the power of each time-domain channel, the electronic device can filter out the multiple time-domain channels with the highest power using the window length, which are designated as in-window channels, while the remaining time-domain channels are designated as out-of-window channels. The out-of-window channels can be considered as the channels where noise is present, and the electronic device can calculate the average power of the out-of-window channels as the noise power.

[0112] For example, the time-domain channel estimation information for each antenna element includes channel estimates for 128 time-domain channels, from which 128 power values ​​can be calculated. With a window length of 16, after filtering out the 16 largest power values, the average value of the remaining 112 power values ​​can be calculated as the noise power.

[0113] Step 214: Select several in-window channels with power greater than the threshold power from multiple in-window channels, and filter out the in-window channel with the highest power from the selected in-window channels. Determine the target time-domain channel estimation information based on the filtered in-window channels; wherein, the threshold power is determined by noise power and a preset third adjustment coefficient.

[0114] The third adjustment factor can be configured as needed; for example, the third adjustment factor can be 1.5.

[0115] The electronic device can multiply the noise power by a third adjustment factor to obtain the threshold power. After obtaining the threshold power, the electronic device can select several in-window channels with power greater than the threshold power from multiple in-window channels, and then filter out the in-window channel with the highest power from the selected in-window channels. Here, the time-domain channel estimates of the filtered in-window channels with power not greater than the threshold power and the in-window channel with the highest power can all be set to zero. The electronic device can construct the target time-domain channel estimate information based on the time-domain channel estimates of the filtered in-window channels and the other time-domain channel estimates set to zero. This target time-domain channel estimate information further removes noise and LOS background in the time domain, and can more accurately characterize the impact of passive target motion on the NLOS (Not Line of Sight) channel.

[0116] Step 215: Perform Fourier transform on the target time-domain channel estimation information of each antenna element to obtain the target channel estimation result of each antenna element in the frequency domain.

[0117] After obtaining the target time-domain channel estimation information for each antenna element, the electronic device can use a Fast Fourier Transform to convert the target time-domain channel estimation information to the frequency domain, thereby obtaining the target channel estimation result for each antenna element in the frequency domain.

[0118] By taking the above measures, the channel estimation information of each antenna element can be cleaned to obtain the target channel estimation result with noise and LOS background removed.

[0119] In one embodiment, before performing step 212, the number of subcarriers in the extracted channel estimation information can be expanded to a second specified number using the boundary repetition method. The second specified number is the number of sampling points that can be processed by the subsequent inverse Fourier transform. In one embodiment, the second specified number can be determined by a first specified number K. For example, the logarithm of K to the base 2 can be calculated, rounded down, and incremented by one to obtain a new integer. This new integer can then be used as a power of 2 to obtain the second specified number.

[0120] The electronic device can repeat the frequency domain channel estimates of the first and last subcarriers in the extracted channel estimation information multiple times, thereby expanding the number of subcarriers to a second specified number. Here, the number of repetitions of the first and last subcarriers in the extracted channel estimation information can be the same. For example, taking a first specified number of 60 and a second specified number of 128 as an example, the expansion process can be represented by the following formula (4):

[0121]

[0122] Where m ranges from 0 to 59, representing the extracted channel estimation information in the middle, including the frequency domain channel estimation values ​​of 60 subcarriers; q is the index of the receiver's antenna array element; k is the subcarrier index; and l is the symbol index. As shown in formula (4), the frequency domain channel estimation value of the first subcarrier is repeated 34 times, and the frequency domain channel estimation value of the last subcarrier is repeated 34 times, thus obtaining the expanded extracted channel estimation information.

[0123] Electronic devices can perform a circular displacement operation on the augmented decimated channel estimation information. For example, the circular displacement operation can be represented by the following formula (5):

[0124]

[0125] Where q is the index of the antenna array element of the receiver; k is the subcarrier index; and l is the symbol index.

[0126] In this embodiment, after performing a circular displacement operation on the expanded extracted channel estimation information, the extracted channel estimation information after the circular displacement operation can be processed by inverse Fourier transform to execute subsequent steps.

[0127] In one embodiment, if the number of subcarriers in the extracted channel estimation information is expanded and a circular displacement operation is performed on the expanded extracted channel estimation information, when determining the target time-domain channel estimation information based on the filtered in-window channels in step 214, the electronic device can construct intermediate time-domain channel estimation information based on the time-domain channel estimation values ​​of the filtered in-window channels and other time-domain channel estimation values ​​set to zero.

[0128] The electronic device can perform zero-padding on the intermediate time-domain channel estimation information. Zero-padding involves adding time-domain channels with estimated time-domain channel values ​​of zero to the intermediate time-domain channel estimation information. By zero-padding, the electronic device can expand the number of channels in the intermediate time-domain channel estimation information to a third specified number, thereby obtaining the target time-domain channel estimation information. The target time-domain channel estimation information includes the time-domain channel estimation information corresponding to the third specified number of channels. In one embodiment, during the zero-padding process, the electronic device can add multiple zeros between multiple time-domain channel estimates in the intermediate time-domain channel estimation information.

[0129] For example, zero-padding can be represented by the following formula (6):

[0130]

[0131] Where n is the third specified quantity; q is the index of the antenna array element of the receiver; and l is the symbol index. The example in formula (6) is to zero-padded intermediate time-domain information estimation information containing 128 sampling points to 512 sampling points. The actual number of sampling points can be configured as needed.

[0132] In one embodiment, when the target time-domain channel estimation information is obtained by padding the intermediate time-domain channel estimation information with zeros, when performing step 215, the electronic device can perform Fourier transform on the target time-domain channel information of each antenna element to obtain the intermediate channel estimation result of each antenna element in the frequency domain.

[0133] The electronic device can perform a circular displacement operation on each intermediate channel estimation result and sample the intermediate channel estimation results after the circular displacement operation to obtain the target channel estimation result for each antenna element. For example, during sampling, a fourth specified number of frequency domain channel estimation values ​​can be selected from the intermediate channel estimation results after the circular displacement operation. Here, the fourth specified number can be configured as needed. For example, if the third specified number is 512, then the fourth specified number can be 240.

[0134] See Figure 4 This is a schematic diagram of the channel estimation information cleaning process provided in an embodiment of this application, as shown below. Figure 4 As shown, for the channel estimation information of any symbol of any antenna element, the frequency domain channel estimation information of that symbol on a first specified number of subcarriers is extracted to obtain the extracted channel estimation information. Figure 4For example, the first specified number is 60. At this point, for any symbol, the frequency domain channel estimation information of that symbol on 60 subcarriers can be obtained. The number of subcarriers in the extracted channel estimation information is expanded to a second specified number using the boundary repetition method. Here, the second specified number is 128. For any symbol, the frequency domain channel estimation value of that symbol on the first subcarrier can be repeated 34 times, and the frequency domain channel estimation value of that symbol on the 60th subcarrier can be obtained, thus yielding the expanded extracted channel estimation information corresponding to that symbol.

[0135] For each symbol of each antenna element, the expanded decimated channel estimation information is subjected to noise reduction processing: a circular displacement operation is performed on the expanded decimated channel estimation information, and then the decimated channel estimation information is transformed into time-domain channel estimation information through inverse Fourier transform. The power corresponding to each channel is determined based on the time-domain channel estimation information. According to a preset window length (e.g., 16), multiple in-window channels with the highest power are divided, and the average power of the 112 out-of-window channels is calculated as the noise power. After determining the threshold power using the third adjustment coefficient and the noise power, several in-window channels with power greater than the threshold power can be selected from the multiple in-window channels. The in-window channel with the highest power is then filtered out from the selected in-window channels. The time-domain channel estimation value of the filtered in-window channels is retained, while the time-domain channel estimation value of other in-window channels is set to zero, thus constructing intermediate time-domain channel estimation information.

[0136] Zero-padding is performed on the intermediate time-domain channel estimation information so that the zero-padding time-domain channel estimation information includes a third specified number of zeros. Figure 4 The target time-domain channel estimation information is obtained by sampling 512 points. Each sampling point represents the time-domain channel estimation value corresponding to a channel.

[0137] The target time-domain channel estimation information of each symbol of each antenna element is subjected to Fourier transform to obtain the intermediate channel estimation result in the frequency domain for each antenna. This intermediate channel estimation result includes 512 sampling points, each sampling point being a frequency domain channel estimation value. A circular shift operation is performed on each intermediate channel estimation result, and the 240 sampling points in the middle are sampled from the intermediate channel estimation result after the circular shift operation as the target channel estimation result for each symbol of each antenna element.

[0138] In one embodiment, see Figure 5 This is provided as an embodiment of the present application. Figure 2 A detailed flowchart of step 280 is shown below. Figure 5 As shown, when executing step 280, steps 281 to 285 can be executed.

[0139] Step 281: Based on the specified channel estimation results of several antenna array elements under each receiver, generate the channel estimation average result corresponding to each receiver, and generate the covariance matrix corresponding to the channel estimation average result to obtain the covariance matrix corresponding to each receiver.

[0140] For each receiver, the channel estimation results for a specified number of antenna elements are averaged to obtain the average channel estimation result corresponding to each receiver. If a receiver has only one antenna element, the specified channel estimation result for that antenna element can be directly used as the average channel estimation result corresponding to that receiver.

[0141] For example, the first receiver has only one antenna element, and the specified channel estimation result of the antenna element... This can be directly used as the average channel estimation result for the first receiver. The second receiver has three antenna elements, and the specified channel estimation results for each antenna element are as follows: Can be calculated The average value of the average value is used to obtain the average channel estimation result of the second receiver.

[0142] After obtaining the channel estimation average result corresponding to the first receiver or the second receiver, since the channel estimation average result can be regarded as a matrix, the electronic device can generate a covariance matrix corresponding to the channel estimation average result. For example, the process of generating the covariance matrix can be represented by the following formula (7):

[0143] R xx =E[XX H (7)

[0144] Where X is the average channel estimation result; E is the identity matrix; R xx Let be the covariance matrix.

[0145] The electronic device can generate corresponding covariance matrices for the first receiver and the second receiver respectively.

[0146] Step 282: Perform eigenvalue decomposition on the covariance matrix of the first receiver to obtain the first observed Doppler velocity of the passive target relative to the first receiver, and perform eigenvalue decomposition on the covariance matrix of the second receiver to obtain the second observed Doppler velocity of the passive target relative to the second receiver.

[0147] Electronic devices can use algorithms such as MUSIC (Multiple Signal Classification Algorithm), ESPRIT (Estimation of Signal Parameters using Rotational Invariance Techniques), and compressed sensing to perform eigenvalue decomposition on the covariance matrix corresponding to the first receiver and the covariance matrix corresponding to the second receiver, respectively, to obtain the Doppler velocity peak caused by the movement of the passive target in the channel. This peak velocity is then used as the first observed Doppler velocity of the passive target relative to the first receiver and the second observed Doppler velocity of the passive target relative to the second receiver.

[0148] When there are multiple moving passive targets in an indoor scene, for each passive target, the first observation Doppler velocity relative to the first receiver and the second observation Doppler velocity relative to the second receiver can be resolved.

[0149] Step 283: Based on the specified channel estimation results of at least two antenna array elements of the second receiver, construct a three-dimensional tensor corresponding to the second receiver, and decompose the two-dimensional matrix corresponding to the current period from the three-dimensional tensor.

[0150] The electronic device can superimpose the specified channel estimation results of at least two antenna elements of the second receiver to construct a three-dimensional tensor corresponding to the second receiver. See also Figure 6 This is a schematic diagram of the coordinate system of a three-dimensional tensor provided in an embodiment of this application, as shown below. Figure 6 As shown, the X-axis is the subcarrier index, the Y-axis is the observation time index (since the symbols in the Wi-Fi signal are transmitted sequentially, the Y-axis can also be regarded as the symbol index), and the Z-axis is the antenna element index of the second receiver (RX2). Figure 6 The arrangement of the coordinate system allows for the superposition of at least two specified channel estimation results corresponding to the second receiver to obtain a three-dimensional tensor.

[0151] After obtaining the three-dimensional tensor, a two-dimensional matrix on the ZX plane corresponding to the observation time of the current period can be selected from the three-dimensional tensor as the two-dimensional matrix corresponding to the current period. Here, the observation time corresponding to the current period can be the time corresponding to the last symbol received in the current period. The decomposed two-dimensional matrix includes the frequency domain channel estimate of that symbol on multiple subcarriers on all antenna elements of the second receiver.

[0152] Step 284: Generate the covariance matrix of the two-dimensional matrix as the angle of arrival covariance matrix, and perform eigenvalue decomposition on the angle of arrival covariance matrix to obtain the angle of arrival of the passive target relative to the second receiver in the current period.

[0153] Electronic devices can generate a covariance matrix from a two-dimensional matrix decomposed from a three-dimensional tensor. After obtaining the covariance matrix, the MUSIC algorithm can be used to perform eigenvalue decomposition on the covariance matrix, thereby obtaining the angle of arrival (AOA) of the passive target relative to the second receiver in the current period.

[0154] Step 285: Track the passive target in the target coordinate system based on the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival; wherein the target coordinate system is determined by the first position information of the first receiver and the second position information of the second receiver.

[0155] After obtaining the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival, passive targets can be tracked in the target coordinate system. Initially, the electronic device can determine the target coordinate system based on the first position information of the first receiver in the indoor scene and the second position information of the second receiver in the indoor scene.

[0156] In one embodiment, the electronic device can determine the target movement speed of a passive target based on a first observed Doppler velocity and a second observed Doppler velocity.

[0157] See Figure 7 This is a schematic diagram of speed fusion provided in an embodiment of this application, as shown below. Figure 7 As shown, the transmitter (TX), the first receiver (RX1), and the second receiver (RX2) are located at different positions in the indoor scene, in the presence of a passive target (TX). Figure 7 During the movement of the passive target (as described above), at each observation moment, the first observed Doppler velocity (or velocity) of the passive target relative to the first receiver can be determined. Figure 7 The RX1 measurement velocity in the second receiver and the second observed Doppler velocity relative to the second receiver. Figure 7 The RX2 measurement velocity is used to fuse the first observed Doppler velocity and the second observed Doppler velocity into the target movement velocity of the passive target in the indoor scene.

[0158] Electronic devices can determine the movement path of a passive target based on the target's moving speed and the cycle duration. The movement path represents the direction and distance of movement of the passive target. Multiplying the target's moving speed by the cycle duration yields the distance the passive target has moved in the current cycle. Then, based on this distance and the direction of movement represented by the target's moving speed, the movement path is determined.

[0159] Electronic devices can track passive targets based on their movement path, the angle of arrival in the current cycle, and the angle of arrival in the previous cycle. See also Figure 8This is a schematic diagram of target tracking provided in an embodiment of this application, as shown below. Figure 8 As shown, the movement path and the angle of arrival for the current period (in this example) Figure 8 Mid-time 2: Target AOA measurement) and the angle of arrival of the previous cycle ( Figure 8 At time 1 (target AOA measurement), a triangle can be formed in the target coordinate system. Based on this, multiple grids can be divided in the target coordinate system, and the probability of the passive target being on each grid in each period can be predicted. After multiple consecutive predictions, the accurate position of the passive target in the target coordinate system can be determined, thus enabling continuous tracking of the passive target. In one embodiment, the tracking results (position at each observation time) can be filtered using Kalman filtering to obtain more accurate tracking results and improve the robustness of tracking and positioning.

[0160] In summary, the proposed solution cleans CSI information to remove the influence of noise and LOS background on NLOS, thereby obtaining channel estimation results that characterize the movement of passive targets. This amplifies the impact of passive target movement on channel state information, obtains specified channel estimation results for each antenna element, accurately parses the target movement speed and angle of arrival of the passive target from multiple specified channel estimation results, and then combines the target movement speed and angle of arrival to achieve accurate tracking of the passive target.

[0161] Figure 9 This is a block diagram of a channel estimation-based positioning device according to an embodiment of the present invention, as shown below. Figure 9 As shown, the device may include:

[0162] The cleaning module 910 is used to periodically clean the channel estimation information corresponding to each antenna element to obtain the target channel estimation result corresponding to each antenna element; wherein, the target channel estimation result includes the frequency domain channel estimation values ​​of multiple symbols on multiple subcarriers in the current period.

[0163] The first selection module 920 is used to select each receiver as a target receiver and each antenna element under the target receiver as a target antenna element.

[0164] The second selection module 930 is used to select the smallest non-zero frequency domain channel estimation value from the target channel estimation results of the target antenna array element as the first adjustment coefficient;

[0165] Processing module 940 is used to process the first adjustment coefficient according to a preset amplification factor to obtain a second adjustment coefficient;

[0166] The first adjustment module 950 is used to adjust the target channel estimation result of the target antenna array element with the first adjustment coefficient to obtain the first channel estimation result;

[0167] The second adjustment module 960 is used to adjust the target channel estimation result of the antenna array element under the specified receiver using the second adjustment coefficient to obtain the second channel estimation result; wherein, the specified receiver is a receiver other than the target receiver;

[0168] The multiplication module 970 is used to perform conjugate multiplication of the first channel estimation result and the second channel estimation result to obtain the specified channel estimation result of the target antenna array element;

[0169] The tracking module 980 is used to track passive targets based on the specified channel estimation results corresponding to each antenna element.

[0170] The specific implementation process of the functions and roles of each module in the above-mentioned device can be found in the implementation process of the corresponding steps in the channel estimation-based tracking method, and will not be repeated here.

[0171] The apparatuses and methods disclosed in the several embodiments provided in this application can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0172] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0173] If a function is implemented as a software module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

Claims

1. A channel estimation-based tracking method applied to a Wi-Fi transceiver system, the Wi-Fi transceiver system comprising a transmitter, a first receiver, and a second receiver, characterized in that, The first receiver includes at least one antenna element, the second receiver includes at least two antenna elements, and the method includes: For the channel estimation information corresponding to each antenna element, periodic cleaning is performed to obtain the target channel estimation result corresponding to each antenna element; wherein, the target channel estimation result includes the frequency domain channel estimation values ​​of multiple symbols on multiple subcarriers in the current period; Each receiver is designated as a target receiver, and each antenna element under the target receiver is designated as a target antenna element. From the target channel estimation results of the target antenna array elements, the smallest non-zero frequency domain channel estimation value is selected as the first adjustment coefficient; The first adjustment coefficient is processed according to the preset amplification factor to obtain the second adjustment coefficient; The target channel estimation result of the target antenna array element is adjusted by the first adjustment coefficient to obtain the first channel estimation result; The target channel estimation result of the antenna array element under the specified receiver is adjusted by the second adjustment coefficient to obtain the second channel estimation result; wherein, the specified receiver is a receiver other than the target receiver; The first channel estimation result and the second channel estimation result are multiplied by conjugate to obtain the specified channel estimation result of the target antenna array element; The passive target is tracked based on the specified channel estimation result corresponding to each antenna element.

2. The method according to claim 1, characterized in that, The channel estimation information corresponding to each antenna element is periodically cleaned to obtain the target channel estimation result for each antenna element, including: For each antenna array element, the frequency domain channel estimation values ​​of multiple symbols on a first specified number of subcarriers are extracted to obtain the extracted channel estimation information. The extracted channel estimation information is transformed into time-domain channel estimation information by inverse Fourier transform, and the power of each channel is determined based on the time-domain channel estimation information. The window is divided into multiple channels with the highest power according to the preset window length, and the average power of the corresponding channels outside the window is calculated as the noise power. Several in-window channels with power greater than a threshold power are selected from multiple in-window channels, and the in-window channel with the highest power is filtered out from the selected in-window channels. The target time-domain channel estimation information is determined based on the filtered in-window channels; wherein, the threshold power is determined by the noise power and a preset third adjustment coefficient. The target time-domain channel estimation information of each antenna element is subjected to Fourier transform to obtain the target channel estimation result of each antenna element in the frequency domain.

3. The method according to claim 2, characterized in that, Before converting the extracted channel estimation information into time-domain channel estimation information through inverse Fourier transform, the method further includes: The number of subcarriers in the extracted channel estimation information is expanded to a second specified number by the boundary repetition method; Perform a circular displacement operation on the expanded extracted channel estimation information.

4. The method according to claim 3, characterized in that, The step of determining the target time-domain channel estimation information based on the filtered in-window channels includes: Based on the time-domain channel estimates of the filtered in-window channels, intermediate time-domain channel estimation information is constructed. The intermediate time-domain channel estimation information is padded with zeros to obtain the target time-domain channel estimation information; wherein, the target time-domain channel estimation information includes time-domain channel estimation values ​​corresponding to a third specified number of channels.

5. The method according to claim 4, characterized in that, The step of performing Fourier transform on the target time-domain channel estimation information of each antenna element to obtain the target channel estimation result in the frequency domain for each antenna element includes: The target time-domain channel estimation information of each antenna element is subjected to Fourier transform to obtain the intermediate channel estimation result of each antenna element in the frequency domain. Perform a circular displacement operation on each intermediate channel estimation result, and sample the intermediate channel estimation results after the circular displacement operation to obtain the target channel estimation result for each antenna element.

6. The method according to claim 1, characterized in that, The designated receiver includes at least two antenna array elements; The step of adjusting the target channel estimation result of the antenna array element under the specified receiver with the second adjustment coefficient to obtain the second channel estimation result includes: The target channel estimation results of at least two antenna elements under the specified receiver are adjusted by the second adjustment coefficient to obtain the adjusted channel estimation result of each antenna element. The adjusted channel estimation results of at least two antenna elements under the specified receiver are averaged to obtain the second channel estimation result.

7. The method according to claim 1, characterized in that, The step of tracking passive targets based on the specified channel estimation results corresponding to each antenna element includes: Based on the specified channel estimation results of several antenna array elements under each receiver, an average channel estimation result corresponding to each receiver is generated, and a covariance matrix corresponding to the average channel estimation result is generated to obtain the covariance matrix corresponding to each receiver. The covariance matrix of the first receiver is decomposed by eigenvalue to obtain the first observed Doppler velocity of the passive target relative to the first receiver, and the covariance matrix of the second receiver is decomposed by eigenvalue to obtain the second observed Doppler velocity of the passive target relative to the second receiver. Based on the specified channel estimation results of at least two antenna elements of the second receiver, a three-dimensional tensor corresponding to the second receiver is constructed, and a two-dimensional matrix corresponding to the current period is decomposed from the three-dimensional tensor. The covariance matrix of the two-dimensional matrix is ​​generated as the angle of arrival covariance matrix, and the angle of arrival covariance matrix is ​​decomposed by eigenvalue to obtain the angle of arrival of the passive target relative to the second receiver in the current period. The passive target is tracked in a target coordinate system based on the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival; wherein the target coordinate system is determined by the first position information of the first receiver and the second position information of the second receiver.

8. The method according to claim 7, characterized in that, The step of tracking the passive target in the target coordinate system based on the first observed Doppler velocity, the second observed Doppler velocity, and the angle of arrival includes: The target movement speed of the passive target is determined based on the first observed Doppler velocity and the second observed Doppler velocity. The movement path of the passive target is determined based on the target's movement speed and cycle duration; wherein the movement path represents the movement direction and movement distance of the passive target. The passive target is tracked based on the movement path, the angle of arrival, and the angle of arrival of the previous cycle.

9. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store processor-executable instructions; The processor is configured to execute the channel estimation-based tracking method according to any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that can be executed by a processor to perform the channel estimation-based tracking method according to any one of claims 1-8.

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