Zero intermediate frequency signal correction method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention relates to the technical field of wireless communication, and discloses a zero intermediate frequency signal correction method and device, electronic equipment and a storage medium. The method comprises the following steps: decoding a fragment of a WiFi signal after automatic gain control locking of a baseband to obtain a signal quality index of the WiFi signal; when the signal quality index of the WiFi signal is higher than a preset threshold, storing and utilizing the fragments of the WiFi signal to obtain an input reference signal; and performing zero intermediate frequency correction by using the input reference signal. Compared with a closed-loop correction mode, the method does not need a hardware loop; compared with a blind correction mode, the method provided by the invention has the effect of obtaining the input reference signal by using the fragments of the WiFi signal so as to realize closed-loop correction.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a zero intermediate frequency signal correction method, device, electronic equipment and storage medium. Background Art

[0002] Currently, the reception of WiFi signals generally adopts a zero intermediate frequency receiving structure. Zero intermediate frequency (ZIF) has the advantages of simple structure and low cost, but it has problems such as DC deviation, local oscillator leakage, and flicker noise.

[0003] There are two traditional zero-IF correction schemes: 1) a closed-loop correction loop, which can obtain the input and output signals for modeling and calculation to obtain the correction coefficients; and 2) blind correction.

[0004] The closed-loop correction loop has the advantage of accurate modeling, but requires a hardware loop; the blind correction method does not require a hardware loop, but has the problem of multi-tap instability and requires a long-term stable signal. Therefore, how to achieve zero intermediate frequency signal correction without requiring a hardware loop and ensuring stability is still a technical gap in this field. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a zero intermediate frequency signal correction method, device, electronic device and storage medium, so that zero intermediate frequency signal correction can be achieved without requiring a hardware loop and while ensuring stability.

[0006] To solve the above technical problems, an embodiment of the present invention provides a zero intermediate frequency signal correction method, comprising: obtaining a signal quality index of the WiFi signal by decoding a segment of a WiFi signal after the baseband is locked by automatic gain control; when the signal quality index of the WiFi signal is higher than a preset threshold, storing and using the segment of the WiFi signal to obtain an input reference signal; and performing zero intermediate frequency correction using the input reference signal.

[0007] An embodiment of the present invention further provides a zero intermediate frequency signal correction device, comprising: a baseband decoding module, configured to obtain a signal quality indicator of the WiFi signal by decoding a segment of the WiFi signal after the baseband is locked by automatic gain control; The data screening module is used to store and use the fragments of the WiFi signal to obtain an input reference signal when the signal quality index of the WiFi signal is higher than a preset threshold; the signal correction module is used to perform zero intermediate frequency correction using the input reference signal.

[0008] An embodiment of the present invention also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned zero intermediate frequency signal correction method.

[0009] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the above-mentioned zero intermediate frequency signal correction method is implemented.

[0010] In an embodiment of the present invention, a signal quality index of the WiFi signal is obtained by decoding a segment of the WiFi signal after the baseband is locked by automatic gain control; when the signal quality index of the WiFi signal is higher than a preset threshold, the segment of the WiFi signal is stored and used to obtain an input reference signal; and zero intermediate frequency correction is performed using the input reference signal. Compared with the closed-loop correction method, the present invention does not require a hardware loop; compared with the blind correction method, the present invention has the effect of achieving closed-loop correction by obtaining an input reference signal using a segment of the WiFi signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0012] Figure 1 is a flow chart of a zero intermediate frequency signal correction method provided according to an embodiment of the present invention; Figure 2 is a structural schematic diagram of a zero intermediate frequency signal correction device according to another embodiment of the present invention; Figure 3 It is a schematic structural diagram of an electronic device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0013] To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0014] An embodiment of the present invention relates to a zero intermediate frequency signal correction method, which can be applied to a zero intermediate frequency signal receiver. In this embodiment, a signal quality index of the WiFi signal is obtained by decoding a fragment of the WiFi signal after the baseband is locked by automatic gain control; when the signal quality index of the WiFi signal is higher than a preset threshold, the fragment of the WiFi signal is stored and used to obtain an input reference signal; and the input reference signal is used to perform zero intermediate frequency correction. Compared with the closed-loop correction method, the present invention does not require a hardware loop; compared with the blind correction method, the present invention can achieve the effect of closed-loop correction by obtaining an input reference signal using a fragment of the WiFi signal. And because the correction is performed using the characteristics of the service signal itself, distortion correction can be performed online in real time without interrupting or interfering with the transmission of the service signal. The implementation details of the zero intermediate frequency signal correction method of this embodiment are described in detail below. The following content is only the implementation details provided for the convenience of understanding and is not necessary for the implementation of this solution.

[0015] like Figure 1 As shown, in step 101, the zero intermediate frequency signal receiver obtains a signal quality indicator of the WiFi signal by decoding a segment of the baseband WiFi signal after the automatic gain control is locked.

[0016] Among them, baseband refers to the inherent frequency band (frequency bandwidth) of the original electrical signal emitted by the signal source (information source, also known as the transmitter) without modulation (spectrum shifting and transformation), and its full name is basic frequency band.

[0017] Automatic Gain Control (AGC) plays a vital role in WiFi communication. AGC is a closed-loop control system that automatically adjusts the signal amplification amplitude according to the size of the input signal to ensure that the output signal amplitude is as large as possible but does not exceed the maximum allowable value of the analog to digital converter (ADC). The purpose of this is to maximize the dynamic range of the signal and reduce the impact of the inherent noise of the system itself, thereby improving the output signal-to-noise ratio.

[0018] The WiFi protocol stipulates that the AGC lock time is less than 5.6 microseconds, but considering the impact of signal to interference plus noise, in an example, in a scenario with a high signal to interference plus noise ratio, the automatic gain control lock time is between 3 microseconds and 4 microseconds.

[0019] WiFi signals are different from communication standards such as Long Term Evolution (LTE) technology or New Radio (NR). WiFi signals have a long period of access permission signals (i.e., legacy signals) before the service signals come. Legacy signals are also a type of WiFi signal, and these WiFi signal fragments contain the L-SIG (Legacy Signalfield) field. Among them, L-SIG is part of the 802.11ac physical layer frame structure, mainly used to transmit MCS (Modulation and Coding Scheme), Length (data length), and parity bits. In the case of 20MHz (megahertz) bandwidth, the MCS field in L-SIG is fixed to a rate of 6Mbps (megabits per second).

[0020] The generation process of the L-SIG field includes the following steps: 1. Generate the bit information of the SIG field: fill in the information of the MCS and Length fields. 2. BCC (Binary Convolutional Code) encoding: 1 / 2 encoding of the bit information. 3. Interleaving: Interleaving the encoded data. The design of L-SIG is to ensure that WiFi devices are compatible with older versions of the WiFi standard. In this way, new WiFi devices can access the network smoothly without changing the existing network settings, ensuring the stability and compatibility of the network.

[0021] In one example, a segment of a WiFi signal contains an L-SIG field. In fact, after AGC locks, a segment of the signal is stored, and the storage amount can be adjusted according to the situation. In addition to the L-SIG field, all signals after locking to the SIG (Signaling) field can be stored. Among them, the SIG field is a field used to transmit control information and data in the communication protocol.

[0022] In one example, the segment of the WiFi signal after the baseband is locked by automatic gain control can be specifically: when the baseband is locked by AGC, the zero intermediate frequency signal receiver performs equalization and decodes the SIG field, and after decoding the SIG field, the above-mentioned stored signal quality indicator will be output.

[0023] Among them, equalization in communication refers to the equalization of channel characteristics, that is, the equalizer at the receiving end produces characteristics opposite to the channel to offset the inter-symbol interference caused by the time-varying multipath propagation characteristics of the channel. In other words, the frequency and time selectivity of the channel are eliminated by the equalizer.

[0024] In one example, the signal quality indicator includes a signal to interference plus noise ratio (SINR).

[0025] In step 102, when the signal quality index of the WiFi signal is higher than a preset threshold, the zero intermediate frequency signal receiver stores and uses the fragments of the WiFi signal to obtain an input reference signal; If the signal quality index is less than a certain threshold (the threshold here can be configured), it proves that the quality of the above-mentioned stored signal is poor and the above-mentioned stored signal is not suitable for algorithm correction.

[0026] If the signal quality index is greater than a certain threshold (the threshold here can be configured), it proves that the quality of the above-mentioned stored signal is good and the above-mentioned stored signal is suitable for algorithm correction.

[0027] In step 103, the zero intermediate frequency signal receiver uses the input reference signal to perform zero intermediate frequency calibration. For example: The legacy local sequence used for synchronization in the baseband storage is correlated with the stored sequence, and the zero-IF algorithm correction calculation is performed after the time and frequency offset correction. Assuming that the signal received at the air interface is called A and the baseband local storage signal is called B (legacy local sequence), A and B can be correlated and calculated to align the delay, and the residual time offset and frequency offset between A and B are filled so that the zero-IF RF signal receiver can perform correction calculations.

[0028] In one example, performing zero intermediate frequency correction using the input reference signal may be: performing time-frequency offset correction on the input reference signal and then implementing zero intermediate frequency correction using a zero intermediate frequency correction algorithm.

[0029] Among them, time-frequency offset correction refers to the correction of time-frequency signals to ensure their accuracy and reliability. Time-frequency offset correction is mainly used in the fields of communication, navigation, finance, etc. The technologies and methods involved include temperature compensation, digital calibration, adaptive calibration algorithm, crystal oscillator selection and software compensation.

[0030] The IQ imbalance problem in a zero-IF receiver is mainly caused by the imbalance between the in-phase component (I) and the quadrature component (Q). In a zero-IF receiver, I and Q represent the in-phase component and the quadrature component, respectively. Ideally, I(t) = cos(ωt) and Q(t) = sin(ωt), but in actual applications, due to the characteristics of RF components, environmental factors, etc., there will be deviations in amplitude and phase between I and Q, resulting in IQ imbalance.

[0031] In the ZIF architecture, a DC compensation system is used to compensate for the DC offset in the receiver. The system consists of a calibrator that periodically performs a calibration routine, samples the output signal of the baseband amplifier for each gain step by successive approximation, and uses this data to calculate the gain, DC offset, and DC differential values ​​to determine the conversion value. Gain Control: The gain control logic and DC control logic work together to adjust the gain through the gain converter. The calibrator programs the gain converter with the value determined during the calibration routine to ensure the stability and accuracy of the system.

[0032] This embodiment does not require a hardware loop; compared to the blind correction method, the present invention can achieve the effect of closed-loop correction by using the input reference signal. From the perspective of digital correction, compared to the one-time correction at power-on or factory tooling, the correction performance will deteriorate with environmental changes. This embodiment can perform real-time online correction through the characteristics of digital correction.

[0033] In this embodiment, the signal quality index of the WiFi signal is obtained by decoding the fragment of the WiFi signal after the baseband is locked by the automatic gain control; when the signal quality index of the WiFi signal is higher than the preset threshold, the fragment of the WiFi signal is stored and used to obtain the input reference signal; and the input reference signal is used to perform zero intermediate frequency correction. Compared with the closed-loop correction method, the present invention does not require a hardware loop; compared with the blind correction method, the present invention can achieve the effect of closed-loop correction by obtaining the input reference signal using the fragment of the WiFi signal.

[0034] The steps of the above method are divided only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this application; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this application.

[0035] Another embodiment of the present invention relates to a zero intermediate frequency signal correction device, such as Figure 2 As shown, including: The baseband decoding module 401 is used to obtain a signal quality index of the WiFi signal by decoding a segment of the WiFi signal after the baseband is locked by automatic gain control; the data screening module 402 is used to store and use the segment of the WiFi signal to obtain an input reference signal when the signal quality index of the WiFi signal is higher than a preset threshold; the signal correction module 403 is used to perform zero intermediate frequency correction using the input reference signal.

[0036] In one example, the segment of the WiFi signal includes an L-SIG field.

[0037] In one example, the signal quality indicator of the WiFi signal includes a signal to interference plus noise ratio.

[0038] In one example, performing zero intermediate frequency correction using the input reference signal may be: performing time-frequency offset correction on the input reference signal and then implementing zero intermediate frequency correction using a zero intermediate frequency correction algorithm.

[0039] In one example, the lock time of the automatic gain control is between 3 microseconds and 4 microseconds.

[0040] It is not difficult to find that this embodiment is a device embodiment corresponding to the above method embodiment, and this embodiment can be implemented in conjunction with the above method embodiment. The relevant technical details mentioned in the above method embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above method embodiment.

[0041] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.

[0042] Another embodiment of the present invention relates to an electronic device, such as Figure 3 As shown, it includes at least one processor 501; and a memory 502 that is communicatively connected to the at least one processor; wherein the memory 502 stores instructions that can be executed by the at least one processor 501, and the instructions are executed by the at least one processor 501 so that the at least one processor 501 can execute the zero intermediate frequency signal correction method as described above.

[0043] The memory 502 and the processor 501 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 501 and the memory 502 together. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 501 is transmitted on a wireless medium via an antenna, and further, the antenna also receives data and transmits the data to the processor 501.

[0044] The processor 501 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 502 can be used to store data used by the processor 501 when performing operations.

[0045] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0046] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0047] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A zero intermediate frequency signal correction method, characterized in that: include: Obtaining a signal quality indicator of the WiFi signal by decoding the WiFi signal after the baseband is locked by automatic gain control; When the signal quality index of the WiFi signal is higher than a preset threshold, storing and using the fragments of the WiFi signal to obtain an input reference signal; The input reference signal is used to perform zero intermediate frequency correction.

2. The zero intermediate frequency signal correction method according to claim 1, characterized in that: The segment of the WiFi signal includes an L-SIG field.

3. The zero intermediate frequency signal correction method according to claim 1, characterized in that: The signal quality indicator of the WiFi signal includes a signal to interference plus noise ratio.

4. The zero intermediate frequency signal correction method according to claim 1, characterized in that: The method of performing zero intermediate frequency correction using the input reference signal comprises: After the input reference signal is corrected for time-frequency offset, zero intermediate frequency correction is implemented through a zero intermediate frequency correction algorithm.

5. The zero intermediate frequency signal correction method according to claim 1, characterized in that: The locking time of the automatic gain control is between 3 microseconds and 4 microseconds.

6. A zero intermediate frequency signal correction device, characterized in that: include: A baseband decoding module, used to obtain a signal quality indicator of the WiFi signal by decoding the WiFi signal after the baseband is locked by automatic gain control; A data screening module, configured to store and use a segment of the WiFi signal to obtain an input reference signal when a signal quality indicator of the WiFi signal is higher than a preset threshold; The signal correction module is used to perform zero intermediate frequency correction using the input reference signal.

7. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can perform the zero intermediate frequency signal correction method as claimed in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the zero intermediate frequency signal correction method according to any one of claims 1 to 5 is implemented.

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