Frequency offset compensation method

Abstract

The embodiment of the application provides a frequency offset compensation method, which comprises: performing time domain frequency offset estimation and compensation on a physical layer protocol data unit (PPDU), and determining a first frequency offset compensation value of the time domain of the PPDU; converting a frequency domain residual frequency offset compensation value of a signaling field of the PPDU into a second frequency offset compensation value of the time domain, and updating the first frequency offset compensation value according to the second frequency offset compensation value. Through the embodiment of the application, the problem of low accuracy of the generated PPDU frequency offset compensation value in the related art is solved, and the effect of generating a more accurate frequency offset compensation value through a feedback mechanism of the frequency domain residual frequency offset is achieved.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a frequency offset compensation method. Background Technology

[0002] Frequency offset estimation and compensation are unavoidable methods and devices on the receiving side of Wireless Fidelity (Wi-Fi) systems. Current frequency offset estimation methods and devices mainly rely on short and long training sequences as defined in 802.11 for coarse and fine frequency offset estimation and compensation, respectively, and then use pilot subcarriers in the frequency domain for residual frequency offset estimation and compensation. However, this method can only solve the frequency offset correction of non-HT PPDUs (non-high throughput PPDUs). With the introduction of other Physical Layer Protocol Data Units (PPDUs) specified in the 802.11 protocol suite, the residual frequency offset estimation method using Kalman filters has significantly reduced its effectiveness for estimating the residual frequency offset of the first few symbols of data symbols. Furthermore, the increase in PPDU length leads to the accumulation of frequency offset with data symbols; when the frequency offset accumulates to a certain level, the accuracy of traditional methods gradually deteriorates. Summary of the Invention

[0003] This application provides a frequency offset compensation method to at least solve the problem of low accuracy of PPDU frequency offset compensation values ​​generated in related technologies.

[0004] According to one embodiment of this application, a frequency offset compensation method is provided, comprising: performing time-domain frequency offset estimation and compensation on a physical layer protocol data unit (PPDU) to determine a first time-domain frequency offset compensation value of the PPDU; converting the frequency-domain residual frequency offset compensation value of the signaling field of the PPDU into a second time-domain frequency offset compensation value; and updating the first frequency offset compensation value according to the second frequency offset compensation value.

[0005] According to another embodiment of this application, a computer program product is also provided, including a computer program and instructions, wherein the computer program and instructions, when executed by a processor, implement the steps in the above method embodiments.

[0006] According to yet another embodiment of this application, a computer-readable storage medium is also provided, wherein a computer program is stored in the computer program, and the computer program is configured to execute the steps in the above method embodiments when it is run.

[0007] According to yet another embodiment of this application, an electronic device is also provided, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the steps in the above method embodiments.

[0008] In this embodiment, determining the frequency offset compensation value includes determining both time-domain and frequency-domain frequency offset compensation values. First, time-domain frequency offset estimation and compensation are performed to determine a first time-domain frequency offset compensation value. Then, a residual frequency offset compensation value in the frequency domain is determined. To feed this residual frequency offset compensation value back to the time-domain frequency offset compensation value, it is converted into a second time-domain frequency offset compensation value. Finally, the second frequency offset compensation value updates the first frequency offset compensation value. Therefore, the problem of low accuracy in the generated PPDU frequency offset compensation values ​​in related technologies can be solved, achieving the effect of generating a more accurate frequency offset compensation value through a feedback mechanism of residual frequency offset in the frequency domain. Attached Figure Description

[0009] Figure 1 This is a hardware structure block diagram of a Wi-Fi system receiving-side device according to the frequency offset compensation method of the present application embodiment;

[0010] Figure 2 This is a flowchart of a frequency offset compensation method according to an embodiment of this application;

[0011] Figure 3 This is a structural block diagram of a frequency offset compensation device according to an embodiment of this application;

[0012] Figure 4 This is a structural block diagram of a frequency offset compensation device according to another embodiment of this application;

[0013] Figure 5 This is a flowchart of a frequency offset compensation method according to another embodiment of this application. Detailed Implementation

[0014] The embodiments of this application will be described in detail below with reference to the accompanying drawings and examples.

[0015] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0016] The method embodiments provided in this application can be executed in a Wi-Fi system receiving device or a similar computing device. The Wi-Fi system receiving device can be a router, a mobile terminal (e.g., a mobile phone terminal) or a computer terminal. Figure 1 This is a hardware structure block diagram of a Wi-Fi system receiving-side device according to an embodiment of the frequency offset compensation method of this application. Figure 1 As shown, the receiving side device may include one or more ( Figure 1Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The Wi-Fi system receiver may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the Wi-Fi system receiver device described above. For example, the Wi-Fi system receiver device may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0017] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the frequency offset compensation method in this embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thus implementing the aforementioned method. The memory 104 may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to a Wi-Fi system receiving device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0018] The transmission device 106 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by a communication provider for the receiving-side device of a Wi-Fi system. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0019] This embodiment provides a frequency offset compensation method for the receiving device of the aforementioned Wi-Fi system. Figure 2 This is a flowchart of a frequency offset compensation method according to an embodiment of this application. This embodiment can be applied to receiving devices in a Wi-Fi system, such as routers, mobile terminals (e.g., mobile phones), or computer terminals. Figure 2 As shown, the process includes the following steps:

[0020] Step S202: Perform time-domain frequency offset estimation and compensation on the Physical Layer Protocol Data Unit (PPDU) to determine the first time-domain frequency offset compensation value of the PPDU.

[0021] Step S202 in this embodiment includes: performing coarse frequency offset estimation of the PPDU in the time domain based on the short training sequence of the PPDU, and performing fine frequency offset estimation of the PPDU in the time domain based on the long training sequence of the PPDU; adding the coarse frequency offset estimation result and the fine frequency offset estimation result of the PPDU to determine the first frequency offset compensation value; wherein, the PPDU is a high-throughput PPDU.

[0022] It should be noted that in the 802.11 standard, the PPDU includes a specific short training sequence of signals used for frequency offset estimation. Coarse frequency offset estimation in the time domain is performed by observing the signal characteristics of the short training sequence. The short training sequence typically contains known frequency characteristics, such as fixed frequency intervals or a specific frequency sequence. By performing time-domain analysis on the short training sequence in the received PPDU, the frequency offset of the signal can be observed. By analyzing the signal characteristics in the short training sequence, the frequency offset of the signal can be estimated, thereby allowing for signal correction or adjustment. This coarse frequency offset estimation helps the receiver perform preliminary signal processing before receiving data, improving the reliability and performance of data transmission.

[0023] In the 802.11 standard, the PPDU includes a specific long training sequence of signals used for time-domain and frequency-domain estimation at the receiver for channel estimation and data demodulation. By processing the long training sequence in the PPDU in the time domain, frequency deviations in the signal can be estimated. Frequency deviation refers to the difference between the actual frequency of the signal and the local clock frequency at the receiver, typically caused by clock drift at both the transmitter and receiver. Time-domain processing of the long training sequence allows for the detection of phase changes in the signal, thereby estimating the frequency deviation. Based on this time-domain processing, frequency calibration can be performed, improving the demodulation performance and accuracy at the receiver. This accurate frequency deviation estimation helps reduce errors during signal demodulation, improving the overall performance and reliability of the communication system.

[0024] In an exemplary embodiment of this application, converting the frequency-domain residual frequency offset compensation value of the signaling field of the PPDU into a second frequency offset compensation value in the time domain includes: demodulating each symbol of the signaling field of the PPDU sequentially; generating a frequency-domain residual frequency offset estimate of the next symbol of the current symbol based on the demodulation results of all data subcarriers of the signaling field; determining the frequency-domain residual frequency offset compensation value of the next symbol based on the frequency-domain residual frequency offset estimate of the next symbol and the time difference between the current symbol and the long training sequence; and converting the frequency-domain residual frequency offset compensation value into a second frequency offset compensation value in the time domain when the signaling field ends or the Lth symbol of the signaling field ends, where L is a positive integer.

[0025] In one embodiment, the data subcarriers of the signaling field are specific frequency subcarriers used to transmit control signaling information. These data subcarriers are typically used to transmit synchronization, modulation, coding, and other control information to ensure normal communication processes and accurate data transmission. In Orthogonal Frequency Division Multiplexing (OFDM) systems, the data subcarriers of the signaling field are specific frequency ranges allocated in the spectrum for signaling transmission. Through these data subcarriers, the communication system can achieve reliable transmission and decoding of signaling information.

[0026] In an exemplary embodiment of this application, demodulating each symbol of the signaling field of the PPDU sequentially includes: performing multiple-input-output (MIMO) demodulation on each symbol of the signaling field of the PPDU sequentially.

[0027] It should be noted that Multiple Input Multiple Output (MIMO) is a wireless communication technology that improves data transmission rate and signal quality by using multiple transmit and receive antennas on the same frequency. Demodulation is the process by which the receiver processes the received signal to recover the original transmitted signal.

[0028] In one embodiment, sequentially performing MIMO demodulation on each symbol of the signaling field of the PPDU includes: sampling and quantizing the received signal to obtain a baseband signal; inputting the received baseband signal into each receiver, with each receiver corresponding to one antenna; performing MIMO demodulation on the signal in each receiver, which typically involves channel estimation and signal demodulation algorithms. Channel estimation is used to estimate channel characteristics, such as attenuation and phase, for compensation during demodulation; using a MIMO demodulation algorithm to demodulate each symbol, converting the symbol into raw data; and performing bit error rate assessment and error correction operations on the demodulated data to ensure data correctness and integrity.

[0029] In an exemplary embodiment of this application, generating a frequency domain residual frequency offset estimate of the next symbol of the current symbol based on the demodulation results of all data subcarriers in the signaling field includes: accumulating the demodulation results of all data subcarriers and obtaining the accumulated value, calculating the phase of the real part and the imaginary part of the accumulated value, and generating a frequency domain residual frequency offset estimate of the next symbol.

[0030] In an exemplary embodiment of this application, determining the frequency domain residual frequency offset compensation value of the next symbol based on the estimated value of the frequency domain residual frequency offset of the next symbol and the time difference between the current symbol and the long training sequence includes: multiplying the estimated value of the frequency domain residual frequency offset of the next symbol by the time difference between the current symbol and the long training sequence to determine the frequency domain residual frequency offset compensation of the next symbol.

[0031] Step S204: Convert the frequency domain residual frequency offset compensation value of the signaling field of the PPDU into the second frequency offset compensation value in the time domain, and update the first frequency offset compensation value according to the second frequency offset compensation value.

[0032] In step S204 of this application embodiment, converting the frequency domain residual frequency offset compensation value of the signaling field of the PPDU into a second frequency offset compensation value in the time domain includes: performing an inverse Fourier transform on the frequency domain residual frequency offset compensation value of the signaling field using an inverse Fourier transform algorithm to generate a second frequency offset compensation value.

[0033] In one embodiment, the updated time-domain frequency offset compensation value is the sum of the first frequency offset compensation value and the second frequency offset compensation value.

[0034] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0035] This embodiment also provides a frequency offset compensation device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementations, or a combination of software and hardware, are also possible and contemplated.

[0036] Figure 3This is a structural block diagram of a frequency offset compensation device according to an embodiment of this application, such as... Figure 3 As shown, the device includes a determination module 10 and an update module 20.

[0037] Determine module 10: Used to estimate and compensate for the time-domain frequency offset of the Physical Layer Protocol Data Unit (PPDU) and determine the first time-domain frequency offset compensation value of the PPDU;

[0038] Update module 20: Used to convert the frequency domain residual frequency offset compensation value of the signaling field of the PPDU into the second frequency offset compensation value in the time domain, and update the first frequency offset compensation value according to the second frequency offset compensation value.

[0039] Figure 4 This is a structural block diagram of a frequency offset compensation device according to another embodiment of this application, as shown below. Figure 4 As shown, the device includes, in addition to Figure 3 In addition to all the modules shown, the determination module 10 also includes an estimation unit 11 and a summation unit 12.

[0040] Estimation Unit 11: Used to perform coarse frequency offset estimation of PPDU in the time domain based on short training sequences of PPDU, and fine frequency offset estimation of PPDU in the time domain based on long training sequences of PPDU.

[0041] Summation unit 12: used to add the coarse frequency offset estimation result and the fine frequency offset estimation result of PPDU to determine the first frequency offset compensation value; where PPDU is a high throughput PPDU.

[0042] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0043] To facilitate understanding of the technical solutions provided in this application, detailed descriptions will be provided below with reference to specific scenario embodiments.

[0044] Figure 5 This is a flowchart of a frequency offset compensation method according to another embodiment of this application, as follows: Figure 5 As shown, the process includes the following steps:

[0045] Step S501: Perform coarse frequency offset estimation in the time domain using short training sequences, and perform fine frequency offset estimation in the time domain using long training sequences.

[0046] Step S502: Perform frequency offset compensation in the time domain.

[0047] Specifically, the frequency offset compensation value T = T0 + T1 + T2, where T0 is the coarse frequency offset estimation result, T1 is the fine frequency offset estimation result, and T2 is the result of converting the frequency domain residual frequency offset estimation value F to the time domain.

[0048] Step S503: Generate frequency domain residual frequency offset compensation values.

[0049] Specifically, the residual frequency offset estimate F0 is multiplied by the time difference between the current symbol and the long training sequence to obtain the frequency domain residual frequency offset compensation value F. The residual frequency offset compensation value is initialized to 0 for the first symbol.

[0050] Step S504: Generate a frequency domain residual frequency offset estimate.

[0051] Specifically, MIMO demodulation is performed on the signaling field, the demodulation results of all data subcarriers are accumulated, and the arctangent value of the accumulated value is calculated as the frequency domain residual frequency offset estimate F0 for the next symbol.

[0052] Step S505: Determine whether the signaling field has ended or whether the Lth data symbol has ended.

[0053] Specifically, if the judgment result is yes, proceed to step S506; if the judgment result is no, proceed to step S503.

[0054] Step S506: Update the frequency offset compensation value.

[0055] Specifically, the estimated residual frequency offset F in the frequency domain is converted to T2, and T in step S502 is updated, while F in step S503 is cleared to zero.

[0056] Embodiments of this application also provide a computer-readable storage medium storing a computer program, wherein the computer program is configured to execute the steps in any of the above method embodiments when run.

[0057] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk.

[0058] Embodiments of this application also provide an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0059] In one exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0060] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0061] This application optimizes the residual frequency offset estimation method for the signaling field of high-throughput PPDUs by utilizing data subcarriers with a larger number of subcarriers, which effectively reduces the estimation variance compared to using pilot subcarriers. This application also reduces the residual frequency offset of the first few symbols of the data symbol to compensate for the performance loss in the early stages of the Kalman filter. Furthermore, it adds a feedback mechanism for the frequency-domain residual frequency offset, periodically feeding back the residual frequency offset in the signaling field and data symbols to update the time-domain compensation value, thereby reducing the residual frequency offset carried by subsequent symbols of the PPDU.

[0062] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0063] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A frequency offset compensation method, characterized in that, include: Perform time-domain frequency offset estimation and compensation on the Physical Layer Protocol Data Unit (PPDU) to determine the first time-domain frequency offset compensation value of the PPDU; The frequency domain residual frequency offset compensation value of the signaling field of the PPDU is converted into a second frequency offset compensation value in the time domain, and the first frequency offset compensation value is updated according to the second frequency offset compensation value. The step of estimating and compensating for the time-domain frequency offset of a Physical Layer Protocol Data Unit (PPDU) to determine a first time-domain frequency offset compensation value for the PPDU includes: performing a coarse time-domain frequency offset estimation on the PPDU based on a short training sequence of the PPDU; performing a fine time-domain frequency offset estimation on the PPDU based on a long training sequence of the PPDU; and adding the coarse and fine frequency offset estimation results of the PPDU to determine the first frequency offset compensation value; wherein the PPDU is a high-throughput PPDU. The step of converting the frequency-domain residual frequency offset compensation value of the signaling field of the PPDU into a second frequency offset compensation value in the time domain includes: demodulating each symbol of the signaling field of the PPDU sequentially; generating a frequency-domain residual frequency offset estimate of the next symbol of the current symbol based on the demodulation results of all data subcarriers of the signaling field; determining the frequency-domain residual frequency offset compensation value of the next symbol based on the frequency-domain residual frequency offset estimate of the next symbol and the time difference between the current symbol and the long training sequence; and converting the frequency-domain residual frequency offset compensation value into a second frequency offset compensation value in the time domain when the signaling field ends or the Lth symbol of the signaling field ends, wherein L is a positive integer.

2. The method according to claim 1, characterized in that, The demodulation of each symbol in the signaling field of the PPDU in sequence includes: Each symbol in the signaling field of the PPDU is sequentially demodulated using a multiple-input-output (MIMO) antenna system.

3. The method according to claim 1, characterized in that, Based on the demodulation results of all data subcarriers in the signaling field, generate the frequency domain residual frequency offset estimate of the next symbol of the current symbol, including: The demodulation results of all data subcarriers are summed to obtain the summed value. The phase of the real and imaginary parts of the summed value is calculated to generate the frequency domain residual frequency offset estimate of the next symbol.

4. The method according to claim 1, characterized in that, The frequency domain residual frequency offset compensation value for the next symbol is determined based on the estimated frequency domain residual frequency offset value of the next symbol and the time difference between the current symbol and the long training sequence, including: The frequency domain residual frequency offset estimate of the next symbol is multiplied by the time difference between the current symbol and the long training sequence to determine the frequency domain residual frequency offset compensation for the next symbol.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the method described in any one of claims 1 to 4.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method described in any one of claims 1 to 4.

7. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the steps of the method described in any one of claims 1 to 4.

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