Method and system for transmit power control of a wi-fi device

Abstract

The application discloses a kind of transmit power control methods of Wi-Fi equipment.Step S1: Wi-Fi equipment calculates A1-T, called first difference value.If |A1-T|≥step, and A1-T>0, enter step S2.If |A1-T|≥step, and A1-T<0, enter step S3.If |A1-T|<step, let second difference value=A1-T, enter step S4.Step S2: the output value "radio frequency gain" is moved by one or more lines as a whole;A2-T calculated based on Nd is called second difference value;then enter step S4.Step S3: the output value "radio frequency gain" is moved by one or more lines as a whole;A2-T calculated based on Nu is called second difference value;then enter step S4.Step S4: if the absolute value of second difference value≥tolerable error range, Wi-Fi equipment adjusts the digital gain of transmit chain digital front end DFE, so that A3-T is as close to zero as possible.The application ensures the timeliness and compensation accuracy of the transmit power adjustment of Wi-Fi equipment.

Description

Technical Field

[0001] This invention relates to a method for transmit power control (TPC) of a Wi-Fi device. Background Technology

[0002] With the rapid development of wireless LAN technology, Wi-Fi has become an indispensable part of modern life. The transmission power of Wi-Fi devices directly affects not only the coverage, signal quality, and stability of the Wi-Fi signal, but also the user experience. Theoretically, increasing the transmission power of Wi-Fi devices can increase the propagation distance and the ability of Wi-Fi signals to penetrate obstacles, but it may also increase electromagnetic interference and the power consumption of Wi-Fi devices.

[0003] Wi-Fi devices typically employ a preset target transmit power based on the Wi-Fi signal modulation method. This is usually the maximum transmit power of the Wi-Fi device while meeting protocol requirements. These protocol requirements include, for example, the spectrum emission mask (SEM) and error vector magnitude (EVM). However, due to hardware factors and temperature, the transmit power of a Wi-Fi device can drift. If the actual transmit power of the Wi-Fi device exceeds the configured target transmit power, the Wi-Fi signal is highly likely to fail to meet the protocol's quality requirements, affecting data transmission efficiency. Furthermore, in areas with dense Wi-Fi networks, excessively high transmit power can increase interference to neighboring Wi-Fi networks, degrading overall network quality. Conversely, if the actual transmit power of the Wi-Fi device is lower than the configured target transmit power, it may reduce the signal coverage area of ​​the Wi-Fi device, affecting user experience. Therefore, the accuracy of a Wi-Fi device's transmit power has a significant impact on its performance.

[0004] The existing method for controlling the transmit power of Wi-Fi devices is as follows: based on the difference between the actual transmit power of the Wi-Fi device and the configured target transmit power, the MAC (Media Access Control) software dynamically adjusts the RF gain level index of the Wi-Fi signal to achieve power compensation, so that the actual transmit power of the Wi-Fi signal is as close as possible to the configured target transmit power. Here, the actual transmit power of the Wi-Fi signal is the voltage mapping result of the power detection module.

[0005] RF gain level index RF gain (dB) 0 -2 1 -1 2 0 3 1 4 2 5 3 6 4 7 5 8 6 9 7 10 8 11 9

[0006] Table 1: RF Gain Level Lookup Table for Wi-Fi Devices

[0007] Please refer to Table 1, which is a simple example of a lookup table for the RF gain level of a Wi-Fi device. A lookup table (LUT) is a technique widely used in digital signal processing. Its main idea is to pre-calculate and store a series of possible output values, and then directly look up the output value based on the input value, thereby reducing the complexity of real-time calculations and improving execution efficiency. The first column of Table 1 is the input value—the RF gain level index, and the second column is the output value—the RF gain. The step precision of the lookup table refers to the difference between the output values ​​corresponding to two adjacent input values, which can be understood as the resolution of the lookup table. In Table 1, the step precision of the RF gain level lookup table for the Wi-Fi device is fixed at 1 dB. When the RF gain level index configured for the transmitted Wi-Fi signal by the Wi-Fi device is 9, the RF gain of the Wi-Fi signal is 7 dB.

[0008] The current method for controlling the transmit power of Wi-Fi devices is to adjust the RF gain level index of the Wi-Fi signal. This method has a certain lag. After adjusting the RF gain level index, PPDUs (physical layer protocol data units) configured with the new RF gain level index begin to enter the MAC hardware buffer. At the same time, the MAC hardware buffer still contains PPDUs configured with the old RF gain level index. PPDUs configured with the new RF gain level index are only transmitted after the old RF gain level index has been completely transmitted. This means that the PPDUs transmitted after adjusting the RF gain level index do not immediately use the latest expected RF gain. For example, as shown in Table 1, assuming the old RF gain level index for the Wi-Fi signal transmitted by the Wi-Fi device is 6, the corresponding RF gain is 4dB. When the power detection module detects that the actual transmit power of the Wi-Fi signal is 2dB higher than the target transmit power, the existing Wi-Fi device transmit power control method directly adjusts the new RF gain level index to 4 (a decrease of 2 levels) based on the power difference, and transmits the new RF gain level index information 4 to the MAC hardware through software configuration. However, the MAC hardware buffer still contains an incompletely transmitted Wi-Fi signal with an RF gain level index of 6. The actual transmit power of the Wi-Fi signal obtained by the power detection module is still 2dB higher than the target transmit power, which causes the RF gain level index to be adjusted back to 2 (a further decrease of 2 levels), causing the actual transmit power of the Wi-Fi signal to deviate from the expected state. This lag caused by the asynchronous nature between the MAC software and hardware affects the real-time performance of the Wi-Fi device's transmit power control and also impacts subsequent power compensation. Summary of the Invention

[0009] The technical problem to be solved by this invention is: how to make the control of the transmission power of Wi-Fi devices more timely and accurate.

[0010] To solve the above-mentioned technical problems, this invention proposes a method for controlling the transmission power of a Wi-Fi device, comprising the following steps: Step S1: The Wi-Fi device obtains the actual transmission power A1 of the currently transmitted Wi-Fi signal and the target transmission power T of the currently transmitted Wi-Fi signal, and calculates A1-T, which is called the first difference; the step precision step of the RF gain level lookup table of the Wi-Fi device is a fixed value. If |A1-T|≥step and A1-T>0, proceed to step S2. If |A1-T|≥step and A1-T<0, proceed to step S3. If |A1-T|<step, set the second difference = A1-T, and proceed to step S4. Step S2: The Wi-Fi device keeps the input value "RF gain level index" in the RF gain level lookup table unchanged, and moves the output value "RF gain" down one or more rows. If the output value in the RF gain level lookup table moves down Nd rows, where Nd is a positive integer, then the estimated actual transmission power of the currently transmitted Wi-Fi signal is A2 = A1 - Nd × step. For each row the output value in the RF gain level lookup table moves down, the Wi-Fi device calculates A2 - T. Nd satisfies: A2 - T < step, and |A2 - T| is as small as possible. The A2 - T calculated based on Nd is called the second difference. Then proceed to step S4. Step S3: The Wi-Fi device keeps the input value "RF Gain Level Index" in the RF gain level lookup table unchanged, and moves the output value "RF Gain" up one or more rows. If the output value in the RF gain level lookup table moves up Nu rows, where Nu is a positive integer, then the estimated actual transmit power of the currently transmitted Wi-Fi signal is A2 = A1 + Nu × step. For each row the output value in the RF gain level lookup table moves up, the Wi-Fi device calculates A2 - T. Nu satisfies: A2 - T < step, and |A2 - T| is as small as possible. The A2 - T calculated based on Nu is called the second difference. Then proceed to step S4. Step S4: If the absolute value of the second difference is less than the tolerable error range, the entire method ends. If the absolute value of the second difference is greater than or equal to the tolerable error range, the Wi-Fi device adjusts the digital gain of the digital front-end (DFE) of the transmit link, adjusting it to make A3 - T as close to zero as possible. Here, A3 represents the actual transmit power of the currently transmitted Wi-Fi signal after adjusting the digital gain.

[0011] Furthermore, in step S1, the Wi-Fi device obtains the target transmit power of the current Wi-Fi signal based on the modulation method of the current Wi-Fi signal.

[0012] Furthermore, in step S2, the RF gain gaps in the RF gain lookup table are filled with the minimum RF gain value.

[0013] Furthermore, in step S2, the output value in the RF gain level lookup table is shifted downwards as a whole, reducing it to the RF gain configured for the currently transmitted Wi-Fi signal, thereby reducing the actual transmission power of the Wi-Fi device.

[0014] Furthermore, in step S3, the missing RF gain values ​​in the RF gain level lookup table are filled with the maximum RF gain values.

[0015] Furthermore, in step S3, the output value in the RF gain level lookup table is shifted upwards as a whole, increasing it to the RF gain configured for the currently transmitted Wi-Fi signal, thereby increasing the actual transmission power of the Wi-Fi device.

[0016] Furthermore, the digital domain of the Wi-Fi device has two digital gain modules for adjusting digital power, namely a digital power scaling module and a digital power fine-tuning module; in step S4, the adjustment of digital gain is achieved by the digital power fine-tuning module.

[0017] Furthermore, different digital power is applied to Wi-Fi signals with different modulation methods. Wi-Fi signals with lower modulation methods are allocated relatively large digital power, while Wi-Fi signals with higher modulation methods are allocated relatively small digital power. This is achieved by the digital power scaling module.

[0018] This invention also proposes a control system for the transmit power of a Wi-Fi device, including a first difference calculation module, an RF gain reduction module, an RF gain increase module, and a digital gain adjustment module. The first difference calculation module is used to obtain the actual transmit power A1 and the target transmit power T of the currently transmitted Wi-Fi signal, and calculates A1-T, which is called the first difference. The step precision step of the RF gain level lookup table of the Wi-Fi device is a fixed value. When |A1-T| < step, the second difference = A1-T. The RF gain reduction module is used to keep the input value "RF gain level index" in the RF gain level lookup table unchanged when |A1-T| ≥ step and A1-T > 0, and shift the output value "RF gain" down one or more rows. For each row shift, A2-T is calculated, where A2 represents the estimated actual transmit power. The number of rows shifted down, Nd, should satisfy: A2-T < step, and |A2-T| should be as small as possible. The A2-T calculated based on Nd is called the second difference. The RF gain amplification module is used to maintain the input value "RF gain level index" in the RF gain level lookup table unchanged when |A1-T|≥step and A1-T<0, and shift the output value "RF gain" upward by one or more rows. For each upward shift, A2-T is calculated, where A2 represents the estimated actual transmit power. The number of rows Nu shifted upward should satisfy: A2-T<step, and |A2-T| should be as small as possible. The A2-T calculated based on Nu is called the second difference. The digital gain adjustment module is used to adjust the digital gain of the transmit link digital front-end (DFE) when the absolute value of the second difference is ≥ the tolerable error range. The adjustment method is to make A3-T as close to zero as possible; where A3 represents the actual transmit power of the currently transmitted Wi-Fi signal after adjusting the digital gain.

[0019] Furthermore, the first difference calculation module includes a power detection module for obtaining the actual transmission power of the Wi-Fi signal; the power detection module further includes an RF detector, an analog-to-digital converter, and a power mapping unit; the RF detector converts the RF power of the Wi-Fi signal transmitted by the Wi-Fi device into an analog voltage; the analog-to-digital converter converts the analog voltage output by the RF detector into a digital voltage, the digital voltage value being linearly related to the actual transmission power of the Wi-Fi signal; the power mapping unit maps the digital voltage output by the analog-to-digital converter to the actual transmission power of the Wi-Fi signal.

[0020] The technical effects achieved by this invention are twofold: firstly, by shifting the output value of the RF gain lookup table as a whole, the RF gain adjustment is realized, ensuring the timeliness of Wi-Fi device transmit power adjustment; secondly, by coordinating RF gain and digital gain, the compensation accuracy of Wi-Fi device transmit power adjustment is improved. This invention enhances the performance of Wi-Fi devices, optimizes their energy consumption and user network experience, and achieves more efficient wireless communication. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the method for controlling the transmit power of a Wi-Fi device proposed in this invention.

[0022] Figure 2 This is a schematic diagram of the transmission power control system for the Wi-Fi device proposed in this invention.

[0023] Figure 3 yes Figure 2 A schematic diagram of the power detection module in the system shown.

[0024] The following are the labels in the attached diagram: 1. First difference calculation module; 2. RF gain reduction module; 3. RF gain increase module; 4. Digital gain adjustment module; 5. RF detector; 6. Analog-to-digital converter; 7. Power mapping unit. Detailed Implementation

[0025] Please see Figure 1 The Wi-Fi device transmit power control method proposed in this invention includes the following steps.

[0026] Step S1: The Wi-Fi device obtains the actual transmit power A1 of the currently transmitted Wi-Fi signal through the power detection module, in dBm (decibels per milliwatt). The Wi-Fi device obtains the target transmit power T of the currently transmitted Wi-Fi signal, in dBm; for example, the target transmit power of the current Wi-Fi signal is obtained based on the modulation method of the current Wi-Fi signal. The Wi-Fi device calculates the difference A1-T between the actual transmit power A1 and the target transmit power T, in dB (decibels), which is called the first difference. A1-T may be a positive number, zero, or a negative number.

[0027] The step precision of the RF gain level lookup table for Wi-Fi devices is a fixed value, meaning that the difference between the output values ​​corresponding to any two adjacent input values ​​is a fixed value. If |A1-T|≥step and A1-T>0, proceed to step S2. If |A1-T|≥step and A1-T<0, proceed to step S3. If |A1-T|<step, set the second difference to A1-T and proceed to step S4.

[0028] Step S2: This situation indicates that the actual transmit power of the Wi-Fi device is too high and needs to be reduced. The Wi-Fi device keeps the input value "RF Gain Level Index" in the RF gain level lookup table unchanged, and shifts the output value "RF Gain" down one or more rows, filling the vacant RF gain with the minimum RF gain value. Shifting the output value in the RF gain level lookup table downwards reduces the RF gain configured for the currently transmitted Wi-Fi signal, thereby reducing the actual transmit power of the Wi-Fi device. Each time the output value in the RF gain level lookup table shifts down one row, the estimated actual transmit power A2 of the currently transmitted Wi-Fi signal decreases by step compared to A1. If the output value in the RF gain level lookup table shifts down Nd rows (where Nd is a positive integer), then A2 = A1 - Nd × step. Each time the output value in the RF gain level lookup table shifts down one row, the Wi-Fi device calculates the difference A2 - T between the estimated actual transmit power A2 and the target transmit power T, in dB. The number of rows Nd by which the output values ​​in the RF gain level lookup table are shifted should satisfy: A2-T<step, and |A2-T| should be as small as possible. The A2-T calculated based on this overall downward shift of the number of rows Nd is called the second difference. Then proceed to step S4.

[0029] For example, if step = 1dB, A1-T is 1.3dB, and A1-T > step. If the output values ​​in the RF gain lookup table are shifted down one row, as shown in Table 2, A2-T is 0.3dB. If the output values ​​in the RF gain lookup table are shifted down two rows, A2-T is -0.7dB. Since the absolute value of A2-T obtained by shifting down one row is the smallest, the method shown in Table 2 of shifting the output values ​​down one row is adopted, i.e., Nd = 1. The A2-T = 0.3dB calculated by shifting down one row is used as the second difference value.

[0030] RF gain level index RF gain (dB) 0 -2 (filled by the minimum RF gain) 1 -2 2 -1 3 0 4 1 5 2 6 3 7 4 8 5 9 6 10 7 11 8

[0031] Table 2: Output values ​​of the RF gain level lookup table for Wi-Fi devices are shifted down one row.

[0032] Step S3: This situation indicates that the actual transmit power of the Wi-Fi device is too low and needs to be increased. The Wi-Fi device keeps the input value "RF Gain Level Index" in the RF gain level lookup table unchanged, and moves the output value "RF Gain" upwards by one or more rows, filling the empty RF gain slots with the maximum RF gain value. Moving the output value in the RF gain level lookup table upwards increases the RF gain configured for the currently transmitted Wi-Fi signal, thereby increasing the actual transmit power of the Wi-Fi device. Each time the output value in the RF gain level lookup table moves upwards by one row, the estimated actual transmit power A2 of the currently transmitted Wi-Fi signal increases by step compared to A1. If the output value in the RF gain level lookup table moves upwards by Nu rows (Nu is a positive integer), then A2 = A1 + Nu × step. Each time the output value in the RF gain level lookup table moves upwards by one row, the Wi-Fi device calculates the difference between the estimated actual transmit power A2 and the target transmit power T, A2 - T, in dB. The number of rows Nu that the output values ​​in the RF gain level lookup table should shift as a whole should satisfy: A2-T<step, and |A2-T| should be as small as possible. The A2-T calculated based on this overall upward shift number Nu is called the second difference. Then proceed to step S4.

[0033] For example, if step = 1dB, A1-T is -1.6dB, and |A1-T| > step. If the output values ​​in the RF gain lookup table are shifted up one row, A2-T becomes -0.6dB. If the output values ​​in the RF gain lookup table are shifted up two rows, as shown in Table 3, A2-T becomes 0.4dB. Since the absolute value of A2-T obtained by shifting up two rows is the smallest, the method shown in Table 3, shifting the output values ​​up two rows, is adopted, i.e., Nu = 2. The A2-T = 0.4dB calculated by shifting up two rows is used as the second difference value.

[0034] RF gain level index RF gain (dB) 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 9 (filled with the maximum value of RF gain) 11 9 (filled with the maximum value of RF gain)

[0035] Table 3: The output values ​​of the RF gain level lookup table for Wi-Fi devices are shifted upwards by two rows.

[0036] Step S4: If the absolute value of the second difference is less than the tolerable error range, the entire method ends.

[0037] If the absolute value of the second difference is greater than or equal to the tolerable error range, the Wi-Fi device adjusts the digital gain of the transmit link DFE (digital front end) via software, for example, using a multiplier or shifter. This changes the actual transmit power of the currently transmitted Wi-Fi signal. The new actual transmit power of the Wi-Fi signal after adjusting the digital gain is denoted as A3. The purpose of adjusting the digital gain is to make A3-T as close to zero as possible.

[0038] The Wi-Fi signal transmitted by a Wi-Fi device first passes through the digital domain and then the analog domain before finally reaching the device's antenna. In the analog domain, the signal power is called radio frequency (RF) power, and RF power amplification relies on RF gain. In the digital domain, the signal power is called digital power, and digital power amplification relies on digital gain. The digital domain has two digital gain modules for adjusting digital power: one is a digital power scaling module, used to scale Wi-Fi signals with different modulation schemes to different digital power levels; the other is a digital power fine-tuning module, used to perform transmit power control. In step S4, adjusting the digital gain is implemented by the digital power fine-tuning module.

[0039] Because the requirements for the EVM (Electronic Power Controller) in Wi-Fi communication protocols vary depending on the modulation method, the maximum output power of Wi-Fi signals with different modulation methods differs while meeting specifications. Specifically, lower-order modulation EVM thresholds are more lenient, allowing for higher peak power. If power boosting relies solely on RF gain, lower-order modulation Wi-Fi signals require significantly higher RF gain than higher-order modulation signals, leading to higher power consumption in Wi-Fi devices. This invention employs differentiated digital power for Wi-Fi signals with different modulation methods, allocating relatively higher digital power to lower-order modulation signals and relatively lower digital power to higher-order modulation signals. This is achieved by a digital power scaling module. Allocating different digital power to Wi-Fi signals with different modulation methods balances RF gain, reducing reliance on analog domain RF gain while meeting the preset power requirements of Wi-Fi devices. This effectively reduces power consumption, optimizes overall energy efficiency, and lowers the heat dissipation requirements of Wi-Fi devices.

[0040] Please see Figure 2 The control system for the transmit power of the Wi-Fi device proposed in this invention includes a first difference calculation module 1, a radio frequency gain reduction module 2, a radio frequency gain increase module 3, and a digital gain adjustment module 4. Figure 2 The system shown corresponds to Figure 1 The method shown.

[0041] The first difference calculation module 1 is used to obtain the actual transmit power A1 and the target transmit power T of the currently transmitted Wi-Fi signal, and calculates A1-T, which is called the first difference. The step precision step of the RF gain level lookup table of the Wi-Fi device is a fixed value. When |A1-T| < step, the second difference = A1-T.

[0042] The RF gain reduction module 2 is used to maintain the input value "RF gain level index" in the RF gain level lookup table unchanged and shift the output value "RF gain" down by one or more rows when |A1-T|≥step and A1-T>0. For each row shift, A2-T is calculated, where A2 represents the estimated actual transmit power. The total number of rows Nd shifted down should satisfy: A2-T<step, and |A2-T| should be as small as possible. The A2-T calculated based on this total number of rows Nd shifted down is called the second difference.

[0043] The RF gain enhancement module 3 is used to maintain the input value "RF gain level index" in the RF gain level lookup table unchanged and shift the output value "RF gain" upward by one or more rows when |A1-T|≥step and A1-T<0. For each upward shift, A2-T is calculated, where A2 represents the estimated actual transmit power. The total number of rows shifted upward, Nu, should satisfy: A2-T<step, and |A2-T| should be as small as possible. The A2-T calculated based on this total number of upward shifts, Nu, is called the second difference.

[0044] The digital gain adjustment module 4 is used to adjust the digital gain of the transmit link DFE when the absolute value of the second difference is greater than or equal to the tolerable error range. After adjusting the digital gain, the new actual transmit power of the Wi-Fi signal is A3. The purpose of adjusting the digital gain is to make A3-T as close to zero as possible.

[0045] The first difference calculation module 1 includes a power detection module for obtaining the actual transmission power of the Wi-Fi signal. Please refer to [link / reference]. Figure 3 As an example, the power detection module further includes an RF detector 11, an analog-to-digital converter 12, and a power mapping unit 13. The RF detector 11 converts the RF power of the Wi-Fi signal (an RF signal) transmitted by the Wi-Fi device into an analog voltage. The analog-to-digital converter 12 converts the analog voltage output by the RF detector 11 into a digital voltage, the digital voltage value of which is linearly related to the actual transmission power of the Wi-Fi signal. The power mapping unit 13 maps the digital voltage output by the analog-to-digital converter 12 to the actual transmission power of the Wi-Fi signal. Preferably, in step S1, for each PPDU transmitted by the Wi-Fi device, a voltage sampling value is read and RF power mapping is performed based on the currently transmitted PPDU to obtain the actual transmission power of the currently transmitted Wi-Fi signal. This not only ensures the real-time nature of the data but also improves the response speed of the Wi-Fi device to changes in RF power.

[0046] Traditional Wi-Fi device transmit power adjustment schemes switch the input value (i.e., RF gain level index) of the RF gain level lookup table based on the difference between the actual transmit power and the target transmit power, which introduces a lag problem. This invention keeps the RF gain level index unchanged and innovatively moves the output value of the RF gain level lookup table to equivalently adjust the RF gain. Furthermore, this invention preferably implements the movement of the RF gain level lookup table output value in hardware, which is faster than software implementation. This avoids the asynchronous problem between software and hardware in existing transmit power control methods, ensuring the timeliness of Wi-Fi device transmit power updates, so that subsequent air interface PPDUs will immediately transmit according to the latest RF gain.

[0047] The basic idea of ​​traditional automatic power control (APC) technology is to compensate for the difference between the actual transmit power and the configured target power to achieve accurate adjustment of the transmit power. This invention, based on APC technology, compensates for the actual transmit power of Wi-Fi devices in real time from two aspects: radio frequency (RF) gain and digital gain. RF gain acts on the RF front end, amplifying the amplitude of the analog RF waveform to increase the output power of the transmitter. Digital gain acts on the digital domain, amplifying the quantization value to increase the digital amplitude. RF gain can achieve a large dynamic range. Digital gain has high adjustment precision and zero power consumption. Both have their advantages and complement each other, enabling the Wi-Fi device's transmit link to achieve an optimal balance between power, efficiency, and accuracy. In this invention, RF gain compensation plays a leading role, achieving rapid adjustment; digital gain compensation serves as an auxiliary means, achieving fine adjustment to improve the accuracy of Wi-Fi device transmit power control, ensuring that the compensation accuracy is not limited by the step precision of the RF gain level lookup table.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the transmit power of a Wi-Fi device, characterized in that, Includes the following steps; Step S1: The Wi-Fi device obtains the actual transmission power A1 of the currently transmitted Wi-Fi signal and the target transmission power T of the currently transmitted Wi-Fi signal, and calculates A1-T, which is called the first difference; The step precision of the RF gain level lookup table for Wi-Fi devices is a fixed value. If |A1-T|≥step and A1-T>0, proceed to step S2; If |A1-T|≥step and A1-T<0, proceed to step S3; If |A1-T|<step, let the second difference = A1-T, and proceed to step S4; Step S2: The Wi-Fi device keeps the input value "RF gain level index" in the RF gain level lookup table unchanged, and moves the output value "RF gain" down one or more rows. If the output value in the RF gain level lookup table moves down Nd rows, where Nd is a positive integer, then the estimated actual transmission power of the currently transmitted Wi-Fi signal is A2 = A1 - Nd × step. For each row the output value in the RF gain level lookup table moves down, the Wi-Fi device calculates A2 - T. Nd satisfies: A2 - T < step, and |A2 - T| is as small as possible. The A2 - T calculated based on Nd is called the second difference. Then proceed to step S4. Step S3: The Wi-Fi device keeps the input value "RF gain level index" in the RF gain level lookup table unchanged, and moves the output value "RF gain" up one or more rows; if the output value in the RF gain level lookup table moves up Nu rows, where Nu is a positive integer, then the estimated actual transmission power of the currently transmitted Wi-Fi signal is A2 = A1 + Nu × step; For each row that the output value in the RF gain level lookup table moves up, the Wi-Fi device calculates A2-T; Nu satisfies: A2-T < step, and |A2-T| is as small as possible; A2-T calculated based on Nu is called the second difference; Then proceed to step S4; Step S4: If the absolute value of the second difference is less than the tolerable error range, the entire method ends; If the absolute value of the second difference is greater than or equal to the tolerable error range, the Wi-Fi device adjusts the digital gain of the digital front-end (DFE) of the transmit link by making A3-T as close to zero as possible. A3 represents the actual transmit power of the Wi-Fi signal after adjusting the digital gain.

2. The method for controlling the transmit power of a Wi-Fi device according to claim 1, characterized in that, In step S1, the Wi-Fi device obtains the target transmit power of the current Wi-Fi signal based on the modulation method of the current Wi-Fi signal.

3. The method for controlling the transmission power of a Wi-Fi device according to claim 1, characterized in that, In step S2, the RF gain level lookup table is filled with the minimum RF gain value for the empty RF gain slots.

4. The method for controlling the transmit power of a Wi-Fi device according to claim 1, characterized in that, In step S2, the output value in the RF gain level lookup table is shifted downwards as a whole, reducing it to the RF gain configured for the currently transmitted Wi-Fi signal, thereby reducing the actual transmission power of the Wi-Fi device.

5. The method for controlling the transmit power of a Wi-Fi device according to claim 1, characterized in that, In step S3, the missing RF gain values ​​in the RF gain level lookup table are filled with the maximum RF gain values.

6. The method for controlling the transmit power of a Wi-Fi device according to claim 1, characterized in that, In step S3, the output value in the RF gain level lookup table is shifted upwards as a whole, which increases the RF gain configured for the currently transmitted Wi-Fi signal, thereby increasing the actual transmission power of the Wi-Fi device.

7. The method for controlling the transmit power of a Wi-Fi device according to claim 1, characterized in that, The digital domain of a Wi-Fi device has two digital gain modules for adjusting digital power: a digital power scaling module and a digital power fine-tuning module. In step S4, the digital gain adjustment is achieved by the digital power fine-tuning module.

8. The method for controlling the transmit power of a Wi-Fi device according to claim 7, characterized in that, Different digital power is applied to Wi-Fi signals with different modulation methods. Wi-Fi signals with lower modulation methods are allocated relatively large digital power, while Wi-Fi signals with higher modulation methods are allocated relatively small digital power. This is achieved by the digital power scaling module.

9. A control system for the transmit power of a Wi-Fi device, characterized in that, It includes a first difference calculation module, an RF gain reduction module, an RF gain increase module, and a digital gain adjustment module; The first difference calculation module is used to obtain the actual transmission power A1 and the target transmission power T of the currently transmitted Wi-Fi signal, and the calculation of A1-T is called the first difference; The step precision of the RF gain level lookup table for Wi-Fi devices is a fixed value; when |A1-T|<step, the second difference = A1-T; The RF gain reduction module is used to keep the input value "RF gain level index" in the RF gain level lookup table unchanged when |A1-T|≥step and A1-T>0, and shift the output value "RF gain" down by one or more rows; for each row shift, calculate A2-T, where A2 represents the estimated actual transmit power; the total number of rows shifted down, Nd, should satisfy: A2-T<step, and |A2-T| should be as small as possible; the A2-T calculated based on Nd is called the second difference; The RF gain enhancement module is used to keep the input value "RF gain level index" in the RF gain level lookup table unchanged when |A1-T|≥step and A1-T<0, and to move the output value "RF gain" upward by one or more rows; for each upward movement, A2-T is calculated, where A2 represents the estimated actual transmit power; the number of rows Nu that is moved upward should satisfy: A2-T<step and |A2-T| should be as small as possible; the A2-T calculated based on Nu is called the second difference. The digital gain adjustment module is used to adjust the digital gain of the transmit link digital front-end (DFE) when the absolute value of the second difference is greater than or equal to the tolerable error range. The adjustment method is to make A3-T as close to zero as possible; A3 represents the actual transmit power of the Wi-Fi signal after adjusting the digital gain.

10. The control system for the transmit power of the Wi-Fi device according to claim 9, characterized in that, The first difference calculation module includes a power detection module for obtaining the actual transmission power of the Wi-Fi signal; the power detection module further includes an RF detector, an analog-to-digital converter, and a power mapping unit; the RF detector converts the RF power of the Wi-Fi signal transmitted by the Wi-Fi device into an analog voltage; the analog-to-digital converter converts the analog voltage output by the RF detector into a digital voltage, the digital voltage value being linearly related to the actual transmission power of the Wi-Fi signal; the power mapping unit maps the digital voltage output by the analog-to-digital converter to the actual transmission power of the Wi-Fi signal.

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