Power Line Carrier Signal Channel Estimation Filtering Method and Device

Abstract

The present invention relates to the technical field of power line carrier communication, and discloses a power line carrier signal channel estimation filtering method and device. The method includes: obtaining a power delay spectrum corresponding to a power line channel estimation result; determining a power threshold based on the magnitudes of multiple powers; sequentially comparing the power threshold with multiple powers in chronological order to determine a filtering window start time and a filtering window descent time; obtaining a filtering window end time based on the time difference between the filtering window start time and the filtering window descent time; wherein, the window function coefficients between the filtering window descent time and the filtering window end time vary with time; determining a target filtering window function based on the filtering window start time, the filtering window descent time, and the filtering window end time; and filtering the power line channel estimation result according to the target filtering window function to obtain a filtered power line channel estimation result. The above solution can improve the accuracy of channel estimation.

Description

Technical Field

[0001] The present invention relates to the technical field of power line carrier communication, and particularly to a power line carrier signal channel estimation filtering method and device. Background Art

[0002] OFDM (Orthogonal Frequency Division Multiplexing) is a digital modulation technology that divides the bandwidth into multiple orthogonal subcarriers, and each subcarrier independently modulates and transmits data simultaneously. OFDMA (Orthogonal Frequency Division Multiple Access) is a multi-user version of OFDM, where the channel is divided into smaller time-frequency resource units (RUs, Resource Units), enabling multiple users to use the same channel resources in parallel, significantly improving the channel utilization rate. Designing a filtering window based on the time-domain impulse response of the channel is an important step in communication system design. Especially in a multipath channel, the design of the filtering window can reduce signal interference and also adjust the channel estimation result, making the channel estimation result closer to the true channel and improving the channel estimation accuracy.

[0003] Therefore, there is an urgent need for a power line carrier signal channel estimation filtering scheme for OFDMA. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a power line carrier signal channel estimation filtering method and device to solve the problem of low channel estimation accuracy.

[0005] In a first aspect, the present invention provides a power line carrier signal channel estimation filtering method applied to an OFDMA system. The method includes:

[0006] Obtain the power delay spectrum corresponding to the power line channel estimation result; the power delay spectrum contains multiple powers arranged in chronological order; the multiple powers are used to respectively indicate the time-domain response of the power line channel of the corresponding user;

[0007] Based on the magnitudes of the multiple powers, determine a power threshold;

[0008] Compare the power threshold with the multiple powers in chronological order to determine the start time of the filtering window and the descent time of the filtering window; the window function coefficients between the start time of the filtering window and the descent time of the filtering window are specified window function coefficients;

[0009] Determine the time difference between the filter window descent time and the filter window termination time based on the time difference between the filter window start time and the filter window descent time, so as to obtain the filter window termination time; wherein, the window function coefficient between the filter window descent time and the filter window termination time changes with time;

[0010] Determine the target filter window function based on the filter window start time, the filter window descent time and the filter window termination time;

[0011] Perform filtering processing on the power line channel estimation result according to the target filter window function to obtain the filtered power line channel estimation result.

[0012] In an alternative embodiment, the determining the power threshold based on the magnitudes of the multiple powers includes:

[0013] Obtain the maximum power value among the multiple powers;

[0014] Determine the power threshold based on the difference between the maximum power value and a preset threshold.

[0015] In an alternative embodiment, the preset threshold is a dynamic threshold; the method further includes:

[0016] Obtain the signal-to-noise ratio of the power line channel input signal;

[0017] Adjust the preset threshold according to the signal-to-noise ratio of the power line channel input signal; the preset threshold is positively correlated with the signal-to-noise ratio of the power line channel input signal.

[0018] In an alternative embodiment, the comparing the power threshold with the multiple powers in chronological order to determine the filter window start time and the filter window descent time includes:

[0019] Compare the multiple powers with the power threshold in chronological order;

[0020] Determine the first power exceeding the power threshold as the filter window start time;

[0021] Determine the last power exceeding the power threshold as the filter window descent time.

[0022] In an alternative embodiment, the determining the time difference between the filter window descent time and the filter window termination time based on the time difference between the filter window start time and the filter window descent time to obtain the filter window termination time includes:

[0023] Calculate the difference between the filter window descent time and the filter window start time;

[0024] Multiply the difference value by a descent coefficient to obtain a descent time value; the descent coefficient is used to indicate the ratio of the time difference between the descent time of the filtering window and the termination time of the filtering window to the time difference between the start time of the filtering window and the descent time of the filtering window;

[0025] Add the descent time value to the descent time of the filtering window to obtain the termination time of the filtering window.

[0026] In an alternative embodiment, the determining the target filtering window function based on the start time of the filtering window, the descent time of the filtering window, and the termination time of the filtering window includes:

[0027] If the current time is less than the start time of the filtering window, determine that the first window function coefficient is 0;

[0028] If the current time is between the start time of the filtering window and the descent time of the filtering window, determine that the second window function coefficient is 1;

[0029] If the current time is between the descent time of the filtering window and the termination time of the filtering window, determine that the third window function coefficient is a target dynamic value; wherein, the target dynamic value is determined based on the quotient of a first time difference and a second time difference; the first time difference is the difference between the current time and the descent time of the filtering window; the second time difference is the difference between the termination time of the filtering window and the descent time of the filtering window;

[0030] If the current time is not less than the termination time of the filtering window, determine that the fourth window function coefficient is 0;

[0031] Determine the target filtering window function based on the first window function coefficient, the second window function coefficient, the third window function coefficient, and the fourth window function coefficient.

[0032] In an alternative embodiment, the method further includes:

[0033] Re-obtain the power delay profile corresponding to the power line channel estimation result at each preset time interval, and re-determine the corresponding target filtering window;

[0034] Update the channel estimation result based on the re-determined target filtering window;

[0035] Based on the updated channel estimation result, perform phase correction on the power line channel input signal.

[0036] In a second aspect, the present invention provides a power line carrier signal channel estimation filtering device, the device includes:

[0037] An acquisition module, configured to acquire a power delay profile corresponding to a power line channel estimation result; the power delay profile includes a plurality of powers arranged in chronological order; the plurality of powers are respectively used to indicate the time domain response of the power line channel of the corresponding user;

[0038] A threshold determination module, configured to determine a power threshold based on the magnitudes of the multiple powers.

[0039] A first determination module, configured to sequentially compare the power threshold with the multiple powers in chronological order to determine a filter window start time and a filter window decay time; a window function coefficient between the filter window start time and the filter window decay time is a specified window function coefficient.

[0040] A second determination module, configured to determine a time difference between the filter window decay time and a filter window termination time based on a time difference between the filter window start time and the filter window decay time, so as to obtain the filter window termination time; wherein, a window function coefficient between the filter window decay time and the filter window termination time changes with time.

[0041] A filter window determination module, configured to determine a target filter window function based on the filter window start time, the filter window decay time, and the filter window termination time.

[0042] A filtering processing module, configured to perform filtering processing on the power line channel estimation result according to the target filter window function to obtain a filtered power line channel estimation result.

[0043] In a third aspect, the present invention provides a computer device, including: a memory and a processor, which are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to execute the power line carrier signal channel estimation filtering method according to the first aspect or any corresponding embodiment thereof.

[0044] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to cause a computer to execute the power line carrier signal channel estimation filtering method according to the first aspect or any corresponding embodiment thereof.

[0045] In a fifth aspect, the present invention provides a computer program product, including computer instructions, and the computer instructions are used to cause a computer to execute the power line carrier signal channel estimation filtering method according to the first aspect or any corresponding embodiment thereof.

[0046] The technical solution provided by the present invention may include the following beneficial effects:

[0047] The power line carrier signal channel estimation filtering method provided by the present invention first obtains the power delay spectrum corresponding to the power line channel estimation result. The power delay spectrum contains multiple powers arranged in chronological order, and these multiple powers are used to respectively indicate the time-domain response of the power line channel of the corresponding user. Then, based on the magnitudes of these multiple powers, a power threshold is determined to determine which powers to retain subsequently. Next, the power threshold is sequentially compared with these multiple powers in chronological order to determine the start time of the filtering window and the decay time of the filtering window. The window function coefficient between the start time of the filtering window and the decay time of the filtering window is a specified window function coefficient. Then, based on the time difference between the start time of the filtering window and the decay time of the filtering window, the time difference between the decay time of the filtering window and the end time of the filtering window is determined to obtain the end time of the filtering window, so as to determine the parameters of the target filtering window according to the retained powers. Finally, based on the start time of the filtering window, the decay time of the filtering window, and the end time of the filtering window, the target filtering window function is determined, and then the power line channel estimation result is filtered according to the target filtering window function to obtain the filtered power line channel estimation result. Filtering the power line channel estimation result with the target filtering window function obtained based on the above solution can effectively filter out noise interference while retaining the main energy path of the channel, improve the communication signal-to-noise ratio, reduce the bit error rate, and can timely and flexibly adjust the shape of the target filtering window according to the power delay spectrum obtained in real time to adapt to different channel characteristics, ensuring the accuracy of channel estimation and enhancing the robustness of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1 is a schematic diagram of the time-domain response of a single-user power line channel in the related art;

[0050] Figure 2 is a schematic diagram of the time-domain response of a multi-user power line channel in the OFDMA scenario in the related art;

[0051] Figure 3 is a simulation diagram of the time-domain response of a single-user power line channel in the related art;

[0052] Figure 4 is a simulation diagram of the time-domain response of a multi-user power line channel in the OFDMA scenario in the related art;

[0053] Figure 5It is a schematic flowchart of a power line carrier signal channel estimation filtering method according to an embodiment of the present invention;

[0054] Figure 6 It is a schematic flowchart of another power line carrier signal channel estimation filtering method according to an embodiment of the present invention;

[0055] Figure 7 It is a schematic diagram of a power delay spectrum according to an embodiment of the present invention;

[0056] Figure 8 It is a schematic diagram of a target filter window according to an embodiment of the present invention;

[0057] Figure 9 It is a schematic flowchart of a channel estimation optimization result according to an embodiment of the present invention;

[0058] Figure 10 It is a structural block diagram of a power line carrier signal channel estimation filtering device according to an embodiment of the present invention;

[0059] Figure 11 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Specific embodiments

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] High-speed Power Line Carrier (HPLC), also known as broadband power line carrier technology, is a technology based on OFDM that uses power lines as a communication medium for data transmission. OFDM (Orthogonal Frequency Division Multiplexing) is a digital modulation technology that divides the bandwidth into multiple orthogonal subcarriers, and each subcarrier independently modulates and transmits data simultaneously. OFDMA (Orthogonal Frequency Division Multiple Access) is a multi-user version of OFDM, where the channel is divided into smaller time-frequency resource units (RUs, Resource Units), enabling multiple users to use the same channel resources in parallel, reducing header and contention overhead, and significantly improving channel utilization.

[0062] In the OFDMA scenario, the power line channel model is usually shared by multiple users on the same power line channel, taking into account factors such as multipath effects, frequency-selective fading, and noise in the power line carrier communication (PLC) environment. The time-domain impulse response of the power line channel in the OFDMA scenario is as follows:

[0063] ,

[0064] where M is the number of users, is the time-domain response of the m-th user.

[0065] By performing a Fourier transform on the time-domain impulse response, the frequency response of the power line channel is obtained as follows:

[0066] ,

[0067] Substituting into it, the frequency response is as follows:

[0068] ,

[0069] where, is the channel frequency response of the m-th user, as follows:

[0070] ,

[0071] where, is the total number of paths of the -th user; is the gain of the -th user on the -th path; is the frequency-dependent attenuation coefficient, usually , , , are all constants, has a value between 0.5 and 1; is the length of the -th user on the -th path; is the delay of the -th user on the -th path, , is the relative permittivity of the wire, is the speed of light.

[0072] The parameters in the power line channel model can be obtained by curve fitting of the measured data or according to empirical values.

[0073] Figure 1 It is a schematic diagram of the time-domain response of a single-user power line channel in the related art. Figure 2 It is a schematic diagram of the time-domain response of a multi-user power line channel in the OFDMA scenario of the related art. Since the distances of different users on the line are different, there is a certain time delay between the time-domain responses of different users' channels, and the total channel response is the sum of the channel responses of each user. Figure 3 It is a simulation diagram of the time-domain response of a single-user power line channel in the related art. Figure 4 It is a simulation diagram of the time-domain response of a multi-user power line channel in the OFDMA scenario of the related art. Figure 3 and Figure 4 In [relevant figure numbers], the abscissa represents the delay time t (unit: μs), and the ordinate represents the time-domain response of the channel.

[0074] Designing a filter window based on the time-domain impulse response of the channel is an important step in the design of a communication system. Especially in a multipath channel, the design of the filter window can reduce inter-symbol interference (ISI) and inter-carrier interference (ICI), and can also adjust the channel estimation result, making the channel estimation result closer to the real channel and improving the accuracy of channel estimation.

[0075] According to an embodiment of the present invention, an embodiment of a power line carrier signal channel estimation filtering method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0076] In this embodiment, a power line carrier signal channel estimation filtering method is provided, which is applied to an OFDMA system and executed by a computer device in the OFDMA system. The computer device can be a desktop computer, a laptop computer, etc. Figure 5 It is a flowchart of the power line carrier signal channel estimation filtering method according to an embodiment of the present invention, as Figure 5 shown, and this process includes the following steps:

[0077] Step S501, obtain the power delay profile corresponding to the power line channel estimation result.

[0078] The power delay profile (PDP) is an important parameter that describes the received power distribution of signals in a multipath channel at different propagation delays. By plotting the relationship between the power of each multipath signal and its corresponding propagation delay, the multipath characteristics of the channel can be intuitively reflected, including phenomena such as path loss, reflection, and diffraction.

[0079] In this embodiment, power line carrier signal channel estimation filtering is performed on the power line channel estimation result to be processed. The finally obtained target filter window can filter the power line channel estimation result, effectively filtering out noise interference while retaining the main energy path of the channel, improving the communication signal-to-noise ratio, and reducing the bit error rate. When performing power line carrier signal channel estimation filtering, it is first necessary to obtain the power delay spectrum corresponding to the power line channel estimation result. The power delay spectrum can be calculated based on the time-domain impulse response in the power line channel estimation result. The power delay spectrum contains multiple powers arranged in chronological order, and these multiple powers are used to respectively indicate the time-domain response of the power line channel of the corresponding user. One power corresponds to the peak value of the time-domain response of the power line channel of one user. There is a time delay problem in the time-domain responses of the power line channels between users, which affects the accuracy of channel estimation.

[0080] Step S502: Determine a power threshold based on the magnitudes of the multiple powers.

[0081] The power threshold is used for subsequent screening of the corresponding multiple powers to retain the main energy path of the channel. The power threshold is determined according to the magnitude relationship of the multiple powers in the power delay spectrum according to a preset rule. The preset rule is set according to actual requirements. Exemplarily, the power retention ratio can be set according to actual experience or experimental data. For example, the multiple powers are arranged from largest to smallest, and the powers ranked in the top 60% are retained, and the minimum value of the retained powers is used as the power threshold; or, the average value of the multiple powers is calculated, and half of the average value is taken as the power threshold, that is, the powers greater than half of the average value are retained.

[0082] Step S503: Compare the power threshold with the multiple powers in chronological order to determine the start time of the filter window and the descent time of the filter window.

[0083] Compare the power threshold with the multiple powers in chronological order, and determine the start time of the filtering window and the decay time of the filtering window according to the comparison results. For example, take the left endpoints of the time intervals corresponding to the powers greater than the power threshold as the start time of the filtering window, and take the right endpoints of the time intervals corresponding to the powers greater than the power threshold as the decay time of the filtering window. Between the start time of the filtering window and the decay time of the filtering window, the window function coefficients of the target filtering window are the specified window function coefficients, that is, the power line channel estimation results corresponding to the powers between the start time of the filtering window and the decay time of the filtering window are retained using the specified window function coefficients. Among them, the window function coefficients are the coefficients of the target filtering window function corresponding to the target filtering window. The independent variable of the target filtering window function is time, and the dependent variable is the time-domain impulse response, which is used to indicate the change of the time-domain impulse response in the power line channel estimation results over time. The specified window function coefficients are set according to actual needs. For example, set to 0.9, indicating that the target filtering window will retain 90% of the time-domain impulse response between the start time of the filtering window and the decay time of the filtering window.

[0084] Step S504: Based on the time difference between the start time of the filtering window and the decay time of the filtering window, determine the time difference between the decay time of the filtering window and the end time of the filtering window to obtain the end time of the filtering window.

[0085] Combined with Figure 4 It can be seen that since the channel time-domain response in the multi-user scenario will eventually decay gradually over time, between the decay time of the filtering window and the end time of the filtering window, set the window function coefficients of the target filtering window to change with time, showing a generally decreasing trend. For example, it can be a decreasing trend according to a preset slope, or a stepwise decrease, or a rapid decrease first and then tend to be stable, so as to be as close as possible to the boundary between the effective signal and the noise, and achieve the purpose of filtering out the noise while retaining the effective signal. It should be noted that since the target filtering window function needs to form a filtering window with the horizontal axis of the coordinate system, the window function coefficient corresponding to the end time of the filtering window is 0. The ratio between the time difference between the decay time of the filtering window and the end time of the filtering window and the time difference between the start time of the filtering window and the decay time of the filtering window can be set in advance according to needs, such as 1:3. Then, based on the time difference between the start time of the filtering window and the decay time of the filtering window, determine the time difference between the decay time of the filtering window and the end time of the filtering window to obtain the end time of the filtering window.

[0086] Step S505: Based on the start time of the filtering window, the decay time of the filtering window, and the end time of the filtering window, determine the target filtering window function.

[0087] At this time, between the start time and the descent time of the filtering window, the window function coefficients of the target filtering window remain unchanged. Between the descent time and the end time of the filtering window, the window function coefficients of the target filtering window gradually decrease to 0. Thus, the target filtering window function between the start time and the end time of the filtering window is obtained according to the window function coefficients between the start time and the end time of the filtering window.

[0088] Step S506: Filter the power line channel estimation result according to the target filtering window function to obtain the filtered power line channel estimation result.

[0089] After obtaining the target filtering window function, the part enclosed between the target filtering window function and the horizontal axis of the coordinate system can be obtained as the target filtering window, and the power line channel estimation result is filtered to obtain the filtered power line channel estimation result as the effective signal, so as to achieve the purpose of retaining the main energy path of the channel.

[0090] The power line carrier signal channel estimation filtering method provided in this embodiment first obtains the power delay spectrum corresponding to the power line channel estimation result. The power delay spectrum contains multiple powers arranged in chronological order, and the multiple powers are used to respectively indicate the time domain response of the power line channel of the corresponding user. Then, based on the magnitudes of the multiple powers, a power threshold is determined to determine which powers to retain subsequently. Then, the power threshold is compared with the multiple powers in chronological order to determine the start time and the descent time of the filtering window. The window function coefficient between the start time and the descent time of the filtering window is the specified window function coefficient. Then, based on the time difference between the start time and the descent time of the filtering window, the time difference between the descent time and the end time of the filtering window is determined to obtain the end time of the filtering window, so as to determine the parameters of the target filtering window according to the retained powers. Finally, based on the start time, the descent time, and the end time of the filtering window, the target filtering window function is determined, and then the power line channel estimation result is filtered according to the target filtering window function to obtain the filtered power line channel estimation result. Filtering the power line channel estimation result based on the target filtering window function obtained by the above scheme can effectively filter out noise interference while retaining the main energy path of the channel, improve the communication signal-to-noise ratio, reduce the bit error rate, and can timely and flexibly adjust the shape of the target filtering window according to the power delay spectrum obtained in real time to adapt to different channel characteristics, ensuring the accuracy of channel estimation and enhancing the robustness of the system.

[0091] In this embodiment, a power line carrier signal channel estimation filtering method is provided, which is applied to an OFDMA system and is executed by a computer device in the OFDMA system. The computer device can be a desktop computer, a laptop computer, etc. Figure 6is a flowchart of a power line carrier signal channel estimation filtering method according to an embodiment of the present invention, as Figure 6 shown, the process includes the following steps:

[0092] Step S601, obtain the power delay profile corresponding to the power line channel estimation result.

[0093] The power delay profile contains multiple powers arranged in chronological order, and the multiple powers are used to respectively indicate the time-domain response of the power line channel of the corresponding user.

[0094] The essence of channel estimation is to estimate using the received synchronization symbol and the known local synchronization symbol, and then use the estimated result to compensate the subsequent data symbols. The received synchronization signal has a PPDU (Physical Protocol Data Unit) signal frame structure, including a preamble (used for synchronizing the receiving device), a frame control field (used for carrying control information), data payload symbols (used for carrying actual data), etc. The accuracy of the channel estimation result directly affects the accuracy of the demodulation of the frame control symbol and the data payload symbol. Therefore, it is very important to improve the accuracy of the channel estimation result. Specifically, when performing channel estimation, first receive the input signal of the power line channel in the time domain through an OFDMA receiver, and after completing frame synchronization, obtain the positive synchronization symbol (Positive Synchronization Pattern, SYNCP) in the preamble of the received input signal, convert the positive synchronization symbol into a frequency-domain signal, and then divide it by the pre-stored local positive synchronization symbol (frequency domain) to obtain the power line channel estimation result, as shown in the following formula:

[0095] ,

[0096] where, is the power line channel estimation result, is the positive synchronization symbol converted into a frequency-domain signal, is the pre-stored local positive synchronization symbol (frequency domain).

[0097] Then, perform an inverse Fourier transform (IFFT, Inverse Fast Fourier Transform) on the column vectors of the channel matrix in the power line channel estimation result, as shown in the following formula:

[0098] ,

[0099] where, is time (delay), is the time-domain impulse response.

[0100] Finally, take the modulus of the time-domain impulse response and then calculate the square value to obtain the power delay profile , as shown in the following formula:

[0101] ,

[0102] where represents the power value at time t, that is, the power value of the signal on the delay path corresponding to this time. The PDP curve reflects the multipath effect of the channel, that is, the distortion of the received signal caused by the signal propagating through multiple paths. On the PDP curve, multiple peaks may appear, and each peak corresponds to a main propagation path. In the single-user scenario of the related technology, there is a maximum peak and several small peaks. Since the multipath delay is small in the single-user scenario, the position of the maximum peak is generally the effective position, that is, the maximum peak corresponds to the propagation path of this single user. Therefore, a relatively narrow rectangular filtering window can be set centered on the maximum peak to achieve effective filtering; while in the multi-user scenario of this embodiment, the maximum peak and other multiple peaks correspond to the propagation paths of multiple users, and the position of the maximum peak does not fully represent the propagation paths of multiple users. At this time, if a relatively narrow rectangular filtering window is set according to the maximum peak as in the related technology, only a small part of the user data can be retained, resulting in the loss of a large amount of user data, and effective filtering in the multi-user scenario cannot be achieved, thereby affecting the accuracy of channel estimation. Therefore, this embodiment provides a power line carrier signal channel estimation filtering method to improve the accuracy of channel estimation in the multi-user scenario.

[0103] Exemplarily, Figure 7 is a schematic diagram of the power delay profile according to an embodiment of the present invention, Figure 7 in which the horizontal axis represents time and the vertical axis represents power (unit: decibel dB).

[0104] Step S602, based on the magnitudes of the multiple powers, determine a power threshold.

[0105] Specifically, the above step S602 includes:

[0106] Step S6021, obtain the maximum power among the multiple powers.

[0107] Obtain the maximum power of each power in the power delay profile .

[0108] Step S6022, based on the difference between the maximum power and a preset threshold, determine the power threshold.

[0109] The preset threshold can be set according to actual requirements, actual experience, experimental data, etc. For example, it is set to (unit: dB), then the power threshold is .

[0110] Optionally, the preset threshold is a dynamic threshold, which is dynamically adjusted according to the signal-to-noise ratio of the input signal of the power line channel. Specifically, first, obtain the signal-to-noise ratio of the input signal of the power line channel. The signal-to-noise ratio can be obtained based on the previous power line channel estimation result. For example, subtract the previous power line channel estimation result without filtering from the previous power line channel estimation result after filtering to obtain the noise energy, and then obtain the signal-to-noise ratio according to the ratio of the current power line channel estimation result (effective signal) after filtering to the noise energy. Then, adjust the preset threshold according to the signal-to-noise ratio of the input signal of the power line channel. The preset threshold is positively correlated with the signal-to-noise ratio of the input signal of the power line channel. The lower the signal-to-noise ratio, the smaller the difference between the noise and the peak value in the PDP curve (the power value at the peak of the mountain), and the smaller the preset threshold, so as to effectively remove the noise; the higher the signal-to-noise ratio, the greater the difference between the noise and the peak value in the PDP curve, and the larger the preset threshold, so as to screen out as many effective peaks as possible.

[0111] Furthermore, the preset threshold can be set in stages according to the numerical range of the signal-to-noise ratio. For example, when the signal-to-noise ratio is in the first numerical range, the preset threshold is set to the first stage value, and when the signal-to-noise ratio is in the second numerical range, the preset threshold is set to the second stage value. The first numerical range is greater than the second numerical range, and the first stage value is greater than the second stage value, so as to perform a more flexible and targeted setting, further improve the accuracy of the screening power, and then improve the accuracy of the channel estimation.

[0112] Step S603, compare the power threshold with the multiple powers in chronological order to determine the start time of the filtering window and the descent time of the filtering window.

[0113] The window function coefficient between the start time of the filtering window and the descent time of the filtering window remains unchanged.

[0114] Specifically, in chronological order, compare the multiple powers with the power threshold in turn, determine the start time of the filtering window as the first power that exceeds the power threshold, and determine the descent time of the filtering window as the last power that exceeds the power threshold.

[0115] Step S604, based on the time difference between the start time of the filtering window and the descent time of the filtering window, determine the time difference between the descent time of the filtering window and the end time of the filtering window to obtain the end time of the filtering window.

[0116] Specifically, the above step S604 includes:

[0117] Step S6041, calculate the difference between the descent time of the filtering window and the start time of the filtering window.

[0118] Subtract the start time of the filtering window from the descent time of the filtering window to obtain the difference between the descent time of the filtering window and the start time of the filtering window.

[0119] Step S6042: Multiply the difference by a descent coefficient to obtain a descent time value.

[0120] The descent coefficient is used to indicate the proportion of the time difference between the descent time of the filter window and the termination time of the filter window to the time difference between the start time of the filter window and the descent time of the filter window. For example, if the descent coefficient is k, the time difference between the start time t1 and the descent time t2 of the filter window (i.e., the difference between the descent time and the start time of the filter window) is t2 - t1, the termination time of the filter window is t3, and the time taken for the window function coefficient to decrease from the descent time of the filter window until it becomes 0 is t3 - t2, then k = (t3 - t2) / (t2 - t1). Therefore, multiplying the difference t2 - t1 between the descent time and the start time of the filter window by the descent coefficient k can obtain the descent time value t3 - t2.

[0121] Exemplarily, the descent coefficient k is 1 / 4, that is, the length of the descent segment of the target filter window (from the descent time to the termination time of the filter window) accounts for 20% of the total length of the target filter window (from the start time to the termination time of the filter window).

[0122] Step S6043: Add the descent time value to the descent time of the filter window to obtain the termination time of the filter window.

[0123] Adding the descent time value t3 - t2 to the descent time t2 of the filter window gives the termination time t3 of the filter window.

[0124] Step S605: Determine the target filter window function based on the start time, descent time, and termination time of the filter window.

[0125] The independent variable of the target filtering window function is time \(t\), and the dependent variable is the time-domain impulse response \(h(t)\) in the power line channel estimation result. The window function coefficient is the coefficient obtained by dividing both sides of the target filtering window function by \(h(t)\) to indicate the coefficient of the target filtering window function varying with time. Specifically, if the current time \(t\) is less than the start time \(t_1\) of the filtering window, the first window function coefficient is determined to be 0, that is, the time-domain impulse response before the start time \(t_1\) of the filtering window is not retained; if the current time \(t\) is between the start time \(t_1\) and the descent time \(t_2\) of the filtering window, the second window function coefficient is determined to be 1, that is, the time-domain impulse response between the start time \(t_1\) and the descent time \(t_2\) of the filtering window is retained; if the current time \(t\) is between the descent time \(t_2\) and the end time \(t_3\) of the filtering window, the third window function coefficient is determined to be the target dynamic value, where the target dynamic value is determined based on the quotient of the first time difference and the second time difference. The first time difference is the difference between the current time \(t\) and the descent time \(t_2\) of the filtering window, and the second time difference is the difference between the end time \(t_3\) and the descent time \(t_2\) of the filtering window, that is, the first time difference is \(t - t_2\), the second time difference is \(t_3 - t_2\), the target dynamic value is related to the quotient \((t - t_2) / (t_3 - t_2)\) of the first time difference and the second time difference, and the target dynamic value is \(1-(t - t_2) / (t_3 - t_2)\). Since the channel time-domain response in the multi-user scenario will eventually decline gradually with time, a third window function coefficient varying with time is set between the descent time and the end time of the filtering window, so as to be as close as possible to the boundary between the effective signal and the noise, and to filter out the noise while retaining the effective signal; if the current time is not less than the end time \(t_3\) of the filtering window, the fourth window function coefficient is determined to be 0, that is, the time-domain impulse response after the end time of the filtering window is not retained.

[0126] Further, based on the first window function coefficient, the second window function coefficient, the third window function coefficient, and the fourth window function coefficient, the target filtering window function is determined. Based on the first window function coefficient, the second window function coefficient, the third window function coefficient, and the fourth window function coefficient, the window function coefficient The expression is as follows:

[0127] ,

[0128] Then the target filtering window function is:

[0129] ,

[0130] Step S606, filter the power line channel estimation result according to the target filtering window function to obtain the filtered power line channel estimation result.

[0131] The target filter window is obtained based on the target filter window function. Specifically, the shape formed by the target filter window and the horizontal axis of the coordinate system is a right-angled trapezoid. Figure 8 is a schematic diagram of a target filtering window according to an embodiment of the present invention.

[0132] Furthermore, the power line channel estimation result can be filtered through the target filter window, and the power line channel estimation result within the right-angled trapezoid formed by the target filter window and the horizontal axis of the coordinate system is retained, that is, the delay and energy information of multiple users in the OFDMA scenario is retained, and the power line channel estimation result after filtering is obtained, so as to achieve the effect of suppressing noise and multipath interference while retaining the main energy path of the channel, improve the signal-to-noise ratio, and reduce the communication bit error rate. In addition, this scheme can adjust the shape of the target filter window in a targeted manner according to the multiple powers in the power delay spectrum corresponding to the power line channel estimation result to adapt to different channel characteristics, thereby enhancing the robustness of the system.

[0133] Optionally, the power delay spectrum corresponding to the power line channel estimation result is reacquired at every preset period, and the corresponding target filter window is re-determined; the channel estimation result is updated based on the re-determined target filter window; based on the updated channel estimation result, the power line channel input signal is phase corrected. That is to say, steps S601 to S604 are repeatedly executed once every preset period to obtain a target filter window adjusted according to the power delay spectrum corresponding to the power line channel estimation result acquired in real time this time, with good timeliness, and then the adjusted target filter window is used to filter the subsequent power line channel estimation results, with good accuracy. Among them, the preset period can be set according to the synchronization period of the receiver.

[0134] For example, Figure 9 1 is a schematic diagram of the channel estimation optimization result flow according to an embodiment of the present invention. Figure 9 As shown, when the power line channel estimation result needs to be optimized, the input signal of the initial power line channel is first obtained, and the initial power line channel estimation result H(k) is obtained according to the positive synchronization signal in the input signal, and then the initial power line channel estimation result H(k) is subjected to inverse Fourier transform IFFT to obtain h(t), and then h(t) is modulo and then squared to obtain the power delay spectrum PDP(t), and then the target filter window function W(t) is obtained according to the power delay spectrum PDP(t). Next, the target filter window function W(t) is Fourier transformed FFT to the frequency domain to obtain the target filter window function W(f) in the frequency domain:

[0135] ,

[0136] Then update the current power line channel estimation result according to the target filter window function W(f) in the frequency domain to obtain the updated power line channel estimation result :

[0137] ,

[0138] Repeat the above process to achieve real-time filtering of the power line channel estimation results, improve the accuracy of the power line channel estimation results, for subsequent phase correction and demodulation, and improve the communication stability and accuracy.

[0139] The power line carrier signal channel estimation filtering method provided in this embodiment first obtains the power delay spectrum corresponding to the power line channel estimation result. The power delay spectrum contains multiple powers arranged in chronological order, and these multiple powers are used to respectively indicate the time-domain response of the power line channel of the corresponding user. Then, based on the magnitudes of these multiple powers, a power threshold is determined to determine which powers to retain subsequently. Then, the power threshold is compared with these multiple powers in chronological order to determine the start time of the filtering window and the descent time of the filtering window. The window function coefficient between the start time of the filtering window and the descent time of the filtering window is the specified window function coefficient. Then, based on the time difference between the start time of the filtering window and the descent time of the filtering window, the time difference between the descent time of the filtering window and the termination time of the filtering window is determined to obtain the termination time of the filtering window, so as to determine the parameters of the target filtering window according to the retained powers. Finally, based on the start time of the filtering window, the descent time of the filtering window, and the termination time of the filtering window, the target filtering window function is determined, and then the power line channel estimation result is filtered according to the target filtering window function to obtain the filtered power line channel estimation result. Filtering the power line channel estimation result based on the target filtering window function obtained by the above scheme can effectively filter out noise interference while retaining the main energy path of the channel, improve the communication signal-to-noise ratio, reduce the bit error rate, and can timely and flexibly adjust the shape of the target filtering window according to the power delay spectrum obtained in real time to adapt to different channel characteristics, ensuring the accuracy of channel estimation and enhancing the robustness of the system.

[0140] In this embodiment, a power line carrier signal channel estimation filtering device is also provided. This device is used to implement the above embodiment and the preferred implementation manners, and those that have been described will not be repeated here. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0141] This embodiment provides a power line carrier signal channel estimation filtering device, which is applied to an OFDMA system, as Figure 10 shown, including:

[0142] An acquisition module 1001 is configured to acquire a power delay profile corresponding to a power line channel estimation result; the power delay profile includes a plurality of powers arranged in chronological order; the plurality of powers are respectively used to indicate the time domain response of the power line channel of the corresponding user.

[0143] A threshold determination module 1002 is configured to determine a power threshold based on the magnitudes of the plurality of powers.

[0144] A first determination module 1003 is configured to sequentially compare the power threshold with the plurality of powers in chronological order to determine a filter window start time and a filter window decay time; the window function coefficients between the filter window start time and the filter window decay time are specified window function coefficients.

[0145] A second determination module 1004 is configured to determine the time difference between the filter window decay time and the filter window end time based on the time difference between the filter window start time and the filter window decay time, so as to obtain the filter window end time; wherein, the window function coefficients between the filter window decay time and the filter window end time vary with time.

[0146] A filter window determination module 1005 is configured to determine a target filter window function based on the filter window start time, the filter window decay time, and the filter window end time.

[0147] A filtering processing module 1006 is configured to perform filtering processing on the power line channel estimation result according to the target filter window function to obtain a filtered power line channel estimation result.

[0148] In an alternative embodiment, the threshold determination module is further configured to:

[0149] Obtain the maximum value of the plurality of powers;

[0150] Determine the power threshold based on the difference between the maximum power value and a preset threshold.

[0151] In an alternative embodiment, the preset threshold is a dynamic threshold; the threshold determination module is further configured to:

[0152] Obtain the signal-to-noise ratio of the power line channel input signal;

[0153] Adjust the preset threshold according to the signal-to-noise ratio of the power line channel input signal; the preset threshold is positively correlated with the signal-to-noise ratio of the power line channel input signal.

[0154] In an alternative embodiment, the threshold determination module is further configured to:

[0155] Sequentially compare the plurality of powers with the power threshold in chronological order;

[0156] Determine the power that first exceeds the power threshold as the start time of the filtering window;

[0157] Determine the last power that exceeds the power threshold as the fall time of the filtering window.

[0158] In an alternative embodiment, the second determination module is further configured to:

[0159] Calculate the difference between the fall time of the filtering window and the start time of the filtering window;

[0160] Multiply the difference by a fall coefficient to obtain a fall time value; the fall coefficient is used to indicate the proportion of the time difference between the fall time of the filtering window and the end time of the filtering window to the time difference between the start time of the filtering window and the fall time of the filtering window;

[0161] Add the fall time value to the fall time of the filtering window to obtain the end time of the filtering window.

[0162] In an alternative embodiment, the filtering window determination module is further configured to:

[0163] If the current time is less than the start time of the filtering window, determine that the first window function coefficient is 0;

[0164] If the current time is between the start time of the filtering window and the fall time of the filtering window, determine that the second window function coefficient is 1;

[0165] If the current time is between the fall time of the filtering window and the end time of the filtering window, determine that the third window function coefficient is a target dynamic value; wherein, the target dynamic value is determined based on the quotient of the first time difference and the second time difference; the first time difference is the difference between the current time and the fall time of the filtering window; the second time difference is the difference between the end time of the filtering window and the fall time of the filtering window;

[0166] If the current time is not less than the end time of the filtering window, determine that the fourth window function coefficient is 0;

[0167] Determine a target filtering window function based on the first window function coefficient, the second window function coefficient, the third window function coefficient, and the fourth window function coefficient.

[0168] In an alternative embodiment, the apparatus further includes an update module, configured to:

[0169] Re-obtain the power delay spectrum corresponding to the circuit line channel estimation result at every preset time interval, and re-determine the corresponding target filtering window;

[0170] Update the channel estimation result based on the re-determined target filtering window;

[0171] Perform phase correction on the power line channel input signal based on the updated channel estimation result.

[0172] The further functional descriptions of the above-mentioned various modules and units are the same as those in the corresponding embodiments above, and will not be elaborated here.

[0173] The power line carrier signal channel estimation and filtering device in this embodiment is presented in the form of functional units. Here, the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0174] The embodiment of the present invention further provides a computer device having the above-mentioned Figure 10 shown power line carrier signal channel estimation and filtering device.

[0175] Please refer to Figure 11 , Figure 11 which is a schematic structural diagram of a computer device provided by an optional embodiment of the present invention. As Figure 11 shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Each component communicates with each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a set of blade servers, or a multi-processor system). Figure 11 One processor 10 is taken as an example in

[0176] The processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, the processor 10 can further include a hardware chip. The above hardware chip can be an application specific integrated circuit, a programmable logic device, or a combination thereof. The above programmable logic device can be a complex programmable logic device, a field programmable gate array, a general array logic, or any combination thereof.

[0177] Among them, the memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0178] The memory 20 may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 may optionally include a memory remotely disposed relative to the processor 10, and these remote memories may be connected to the computer device through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0179] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk, or a solid-state drive; the memory 20 may further include a combination of the above types of memories.

[0180] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30, and the output device 40 may be connected through a bus or other means. Figure 11 Taking connection through a bus as an example.

[0181] The input device 30 may receive input digital or character information, and generate key signal inputs related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touchpad, a pointing stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED), and a haptic feedback device (e.g., a vibration motor), etc. The above display device includes but is not limited to a liquid crystal display, a light-emitting diode, a display, and a plasma display. In some alternative embodiments, the display device may be a touch screen.

[0182] Embodiments of the present invention also provide a computer-readable storage medium. The methods according to the embodiments of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code that is originally stored in a remote storage medium or a non-transitory machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the methods described herein can be stored as such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods shown in the above embodiments are implemented.

[0183] A part of the present invention can be applied as a computer program product, for example, computer program instructions. When executed by a computer, through the operation of the computer, the methods and / or technical solutions according to the present invention can be called or provided. Those skilled in the art should understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Herein, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to the computer.

[0184] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the protection scope of the present invention.

Claims

1. A power line carrier signal channel estimation filtering method, applied to an OFDMA system, characterized in that The method includes: Obtaining a power delay profile corresponding to the power line channel estimation result; the power delay profile contains a plurality of powers arranged in chronological order; the plurality of powers are used to respectively indicate the time domain response of the power line channel of the corresponding user; Determining a power threshold based on the magnitudes of the plurality of powers; Sequentially comparing the power threshold with the plurality of powers in chronological order to determine a filter window start time and a filter window decay time; the window function coefficient between the filter window start time and the filter window decay time is a specified window function coefficient; Determining the time difference between the filter window decay time and the filter window end time based on the time difference between the filter window start time and the filter window decay time to obtain the filter window end time; wherein, the window function coefficient between the filter window decay time and the filter window end time changes with time; Determining a target filter window function based on the filter window start time, the filter window decay time, and the filter window end time; Filtering the power line channel estimation result according to the target filter window function to obtain a filtered power line channel estimation result.

2. The method according to claim 1, wherein The determining a power threshold based on the magnitudes of the plurality of powers includes: Obtaining the maximum power among the plurality of powers; Determining the power threshold based on the difference between the maximum power and a preset threshold.

3. The method according to claim 2, wherein The preset threshold is a dynamic threshold; the method further includes: Obtaining the signal-to-noise ratio of the input signal of the power line channel; Adjusting the preset threshold according to the signal-to-noise ratio of the input signal of the power line channel; the preset threshold is positively correlated with the signal-to-noise ratio of the input signal of the power line channel.

4. The method according to claim 2, characterized in that, The sequentially comparing the power threshold with the plurality of powers in chronological order to determine the filter window start time and the filter window decay time includes: Sequentially comparing the plurality of powers with the power threshold in chronological order; Determining the first power exceeding the power threshold as the filter window start time; Determining the last power exceeding the power threshold as the filter window decay time.

5. The method according to claim 4, wherein The determining the time difference between the filter window decay time and the filter window end time based on the time difference between the filter window start time and the filter window decay time to obtain the filter window end time includes: Calculating the difference between the filter window decay time and the filter window start time; Multiplying the difference by a decay coefficient to obtain a decay time value; the decay coefficient is used to indicate the proportion of the time difference between the filter window decay time and the filter window end time to the time difference between the filter window start time and the filter window decay time; Adding the decay time value to the filter window decay time to obtain the filter window end time.

6. The method according to claim 5, characterized in that, The determining a target filter window function based on the filter window start time, the filter window decay time, and the filter window end time includes: If the current time is less than the filter window start time, determining that the first window function coefficient is 0; If the current time is between the filter window start time and the filter window decay time, determining that the second window function coefficient is 1; If the current time is between the falling time and the termination time of the filtering window, determine that the third window function coefficient is the target dynamic value; wherein, the target dynamic value is determined based on the quotient of the first time difference and the second time difference; the first time difference is the difference between the current time and the falling time of the filtering window; the second time difference is the difference between the termination time and the falling time of the filtering window; If the current time is not less than the termination time of the filtering window, determine that the fourth window function coefficient is 0; Based on the first window function coefficient, the second window function coefficient, the third window function coefficient, and the fourth window function coefficient, determine the target filtering window function.

7. A power line carrier signal channel estimation filtering device is applied to an OFDMA system, characterized in that The device includes: An acquisition module, configured to acquire a power delay profile corresponding to an estimated result of a power line channel; the power delay profile includes a plurality of powers arranged in chronological order; the plurality of powers are respectively used to indicate the time domain response of the power line channel of the corresponding user; A threshold determination module, configured to determine a power threshold based on the magnitudes of the plurality of powers; A first determination module, configured to sequentially compare the power threshold with the plurality of powers in chronological order to determine a filtering window start time and a filtering window falling time; the window function coefficient between the filtering window start time and the filtering window falling time is a specified window function coefficient; A second determination module, configured to determine the time difference between the filtering window falling time and the filtering window termination time based on the time difference between the filtering window start time and the filtering window falling time, so as to obtain the filtering window termination time; wherein, the window function coefficient between the filtering window falling time and the filtering window termination time changes with time; A filtering window determination module, configured to determine a target filtering window function based on the filtering window start time, the filtering window falling time, and the filtering window termination time; A filtering processing module, configured to perform filtering processing on the estimated result of the power line channel according to the target filtering window function to obtain a filtered estimated result of the power line channel.

8. A computer device, characterized in that, Comprising: A memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to execute the power line carrier signal channel estimation filtering method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the power line carrier signal channel estimation filtering method according to any one of claims 1 to 6.

10. A computer program product, characterized in that, Including computer instructions, the computer instructions are used to cause a computer to execute the power line carrier signal channel estimation filtering method according to any one of claims 1 to 6.

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