CN112804744B

CN112804744B - Automatic gain control method and device suitable for NR

Info

Publication number: CN112804744B
Application number: CN202110408222.7A
Authority: CN
Inventors: 陈政; 檀甲甲; 朱学庆
Original assignee: ASR Microelectronics Co Ltd
Current assignee: ASR Microelectronics Co Ltd
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-08-13
Anticipated expiration: 2041-04-16
Also published as: CN112804744A

Abstract

The application discloses an automatic gain control method suitable for 5G NR. Step S21: and the mobile terminal completes cell search and time-frequency synchronization. Step S22: taking the time slot as a unit measurement, and counting the stations in the time slotHaving the average power of the signal corresponding to the OFDM symbol and obtaining the maximum value P therein_Max. Step S23: gain control value G calculated from the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf. Step S24: according to the set threshold value, the air interface signal power value P calculated by each measurement is judged_RfThe section in which it is located. Step S25: acquiring air interface signal power value P calculated by continuous two-time measurement_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr. Step S26: the gain control value G calculated by the current measurement_CurrControl is effected at the appropriate time. According to the method and the device, automatic gain control is performed when the statistical signal is judged to be effective, and the defect of a specific scene is avoided.

Description

Automatic gain control method and device suitable for NR

Technical Field

The present invention relates to an Automatic Gain Control (AGC) method for a mobile terminal, and more particularly, to an AGC method for a 5G (the fifth generation mobile communication technology) NR (new radio) mobile terminal.

Background

The power at which the mobile terminal receives the signal varies continuously over time due to multipath fading of the signal, near-far effects, and environmental variations. In order to ensure that the signal sent to the demodulation unit after being received by the antenna maintains a relatively proper amplitude, the mobile terminal needs to complete automatic tracking of the received signal power and automatic adjustment of the gain through the automatic gain control unit.

Referring to fig. 1, the conventional automatic Gain control apparatus in a mobile terminal includes a Power Detector (Power Detector) 12, an automatic Gain control (AGC Controller) 14, and a Gain Controller (Gain Controller) 16. First, the power detection unit 12 periodically counts the average power of the received signal, and then the automatic gain control unit 14 calculates the power of the received signal to obtain the power of an air interface (air interface) signal, performs filtering processing, and finally obtains a gain control value sent to the gain controller 16, and takes effect at a proper position. Different mobile terminal receivers may differ somewhat in the specific structure, but the basic principles are consistent.

Referring to fig. 2, a conventional automatic gain control method in a mobile terminal includes the following steps.

Step S11: the mobile terminal completes cell search and time-frequency synchronization and obtains an initial value of gain control at the same time. Simultaneously obtaining the average power initial value P of the signals_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}

Step S12: the power detection unit periodically measures, counts the average power of the received signal and obtains a statistical result P_Ave。

Step S13: the automatic gain control unit obtains the statistical result P of the current measurement_AveThen, first, the gain control value G calculated from the last measurement_PrevThrough P_AveCalculating to obtain the empty signal power value P_Rf(ii) a Then, a pair of air interface signal powers P is formed according to a formula_RfCarrying out Alpha filtering and obtaining the signal power value P after the Alpha filtering_{Rf_Alpha}(ii) a Finally, according to a formula II, the signal power value P after Alpha filtering is obtained_{Rf_Alpha}And corresponding target signal power P_{Rf_Target}Comparing to obtain gain control value G calculated by the current measurement_Curr。

Formula one is P_{Rf_Alpha}＝(1－α)×P_{Rf_Alpha}＋α×P_Rf. Where Alpha represents the coefficients of the Alpha filter. P on the left side of the equation_{Rf_Alpha}Represents the signal power value after Alpha filtering of this time, P on the right side of the equation_{Rf_Alpha}Representing historical values of the Alpha filter output.

Formula two is G_Curr＝G_Prev＋(P_{Rf_Target}－P_{Rf_Alpha}). If it is the first measurement, the gain control value G is calculated_CurrThen, the initial value of gain control obtained in step S11 is used as the gain control value G calculated in the last measurement_Prev。

Step S14: the automatic gain control unit calculates the gain control value G of the current measurement_CurrTo the gain controller and the control is effected at the appropriate time.

In a conventional LTE (Long-Term Evolution) terminal, when a baseband periodically counts average power of a received Signal, each time of counting can be considered to be valid because of the presence of a CRS (Cell Reference Signal), which can also ensure that automatic gain control can normally work. Referring to fig. 3, the 14 OFDM symbols (OFDM Symbol; where OFDM represents orthogonal frequency-division multiplexing) in each subframe (subframe) are respectively represented as blocks numbered from 0 to 13. Blank squares represent OFDM symbols that may not contain a valid signal; the grey squares represent OFDM symbols containing at least CRS signals. For convenience of explanation, it is assumed that the baseband fixedly measures the average power of 7 OFDM symbols numbered between 0 and 6 to perform automatic gain control. Since the OFDM symbols numbered 0 and 4 fixedly contain CRS signals, the measurement can always be considered to be valid, and it is ensured that the automatic gain control can also work normally.

The "Always On" signal, which occupies a fixed resource, like the CRS of LTE, is abandoned in the standard of 5G NR. For the 5G NR terminal, since no CRS signal exists, the validity of the measurement cannot be guaranteed, and the automatic gain control may not work normally.

Referring to fig. 4, which is a scenario one of the 5G NR, 14 OFDM symbols in each slot (slot) are respectively represented as blocks numbered from 0 to 13. Blank squares represent OFDM symbols that do not contain a valid signal; the dark grey squares represent OFDM symbols containing valid signals transmitted by the base station. The effective signal is data transmitted from the base station to the mobile terminal, and is noise as opposed to the effective signal. For convenience of explanation, it is assumed that the baseband fixedly measures the average power of 7 OFDM symbols numbered between 0 and 6 to perform automatic gain control. Since the OFDM symbol numbered 3 in the measurement length contains an effective signal, the measurement can be considered to be effective, thereby basically ensuring that the automatic gain control can normally operate.

Referring to fig. 5, which is a second scenario of 5G NR, the 14 OFDM symbols in each slot are represented as blocks numbered from 0 to 13. Blank squares represent OFDM symbols that do not contain a valid signal; the dark grey squares represent OFDM symbols containing valid signals transmitted by the base station. For convenience of explanation, it is assumed that the baseband fixedly measures the average power of 7 OFDM symbols numbered between 0 and 6 to perform automatic gain control. Since the length of the current measurement does not contain a valid signal, the current measurement is invalid. If the gain control value G is carried out according to the measured value_CurrThe calculation and updating of (a) may cause the gain to be too large to cause data saturation, which affects the demodulation performance.

Referring to fig. 6, this is a scenario three of 5G NR, where 14 OFDM symbols in each slot are represented as blocks numbered from 0 to 13. In a time slot shown in this scenario, all the squares are blank squares, indicating OFDM symbols that do not contain a valid signal. For convenience of explanation, it is assumed that the baseband fixedly measures the average power of 7 OFDM symbols numbered between 0 and 6 to perform automatic gain control. Since the valid signal transmitted by the base station is not included in the measurement length, the measurement is invalid. If the gain control value G is carried out according to the measured value_CurrThe calculation and updating of (a) may cause the gain to be too large to cause data saturation, which affects the demodulation performance.

As can be seen from the different scenarios shown in fig. 3 to fig. 6, the conventional automatic gain control method for the LTE terminal does not determine the validity of the statistical signal, but directly calculates a new gain control value by using the statistical result. This is because the presence of CRS signals in the LTE standard can ensure that the statistical signal is always valid. If the CRS signal is abandoned by the 5G NR standard, the gain value is too large and data is saturated under certain scenes, thereby affecting the performance of the receiver.

Disclosure of Invention

The technical problem to be solved by the application is to provide a new automatic gain control method, which can ensure that a 5G NR terminal can accurately measure a useful signal, and quickly complete the tracking of signal average power and the adjustment of gain after finishing the judgment of the validity of a statistical signal, thereby ensuring that a signal sent to a receiving end demodulation module always keeps a relatively proper amplitude.

In order to solve the above technical problem, the present application proposes an automatic gain control method suitable for 5G NR, including the following steps. Step S21: the mobile terminal completes cell search and time-frequency synchronization and obtains the initial value P of the average power of the signal_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}. Step S22: the power detection unit measures by taking a time slot as a unit, counts the average power of signals corresponding to all OFDM symbols in the time slot, and obtains the maximum value P in the average power_Max. Step S23: the automatic gain control unit calculates the gain control value G according to the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf. Step S24: the automatic gain control unit judges the air interface signal power value P calculated by each measurement according to the set threshold value_RfThe section in which it is located. Step S25: the automatic gain control unit obtains the empty signal power value P calculated by continuous two measurements_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr. Step S26: the automatic gain control unit calculates the gain control value G of the current measurement_CurrTo the gain controller and the control is effected at the appropriate time. The method takes OFDM symbols as a unit to count the signal power, firstly finishes the judgment of the validity of the statistical signal, calculates a new gain control value to carry out automatic gain control when the statistical signal is valid, thereby avoiding the defects that the gain value is overlarge and data is saturated possibly under a specific scene.

Alternatively, the step S22 is changed to a step S22 a: the power detection unit measures in time slot unitCounting the signal power corresponding to partial OFDM symbol in the time slot and obtaining the maximum value P_Max. This is an alternative implementation of step S22, which can reduce the hardware overhead and the amount of computation.

Alternatively, the step S22 is changed to a step S22 b: the power detection unit measures by taking a time slot as a unit, counts signal power corresponding to part or all OFDM symbols in the time slot, and obtains an average value P of the first k maximum values_MaxAnd k is a natural number greater than or equal to 2. This is an alternative implementation of step S22, which can improve the measurement accuracy.

Preferably, in the steps S22, S22a, and S22b, the measurement and the statistics are periodically performed in units of time slots. In other application scenarios, the measurements and statistics may not be performed periodically.

Further, in step S23, if it is the first measurement, the air interface signal power value P is calculated_RfThen, the gain control initial value G obtained in step S21 is used_InitGain control value G calculated as last measurement_Prev. This is a way of handling in special scenarios.

Further, in step S24, the air interface signal power value P calculated in each measurement_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a first threshold value P in between_{Rf_TH1}And a second threshold value P_{Rf_TH2}First threshold value P_{Rf_TH1}Greater than a second threshold value P_{Rf_TH2}(ii) a Maximum possible value P_{Rf_Max}And a first threshold value P_{Rf_TH1}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into the first interval R1, the time slot of the current measurement necessarily contains the effective signal sent by the base station; first threshold value P_{Rf_TH1}And a second threshold value P_{Rf_TH2}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into a second interval R2, the time slot of the current measurement possibly contains a valid signal sent by the base station; second threshold value P_{Rf_TH2}With the minimum possible value P_{Rf_Min}BetweenA third interval R3, a null signal power value P calculated by each measurement_RfIf the time slot falls in the third interval R3, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be measured by the power statistics. This is the first specific implementation of step S24.

Optionally, in the step S24, the first threshold P is dynamically changed according to the bandwidth of the rf channel filter due to the partial bandwidth BMP switching of the 5G NR system_{Rf_TH1}A second threshold value P_{Rf_TH2}The value of (a). In other application scenarios, the first threshold P_{Rf_TH1}A second threshold value P_{Rf_TH2}The value of (a) may also be fixed.

Further, in step S24, the air interface signal power value P calculated in each measurement_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a third threshold value P in between_{Rf_TH}(ii) a Maximum possible value P_{Rf_Max}And a third threshold value P_{Rf_TH}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into the first interval R1, the time slot of the current measurement necessarily contains the effective signal sent by the base station; third threshold value P_{Rf_TH}With the minimum possible value P_{Rf_Min}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the second interval R2, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be detected by the power statistics. This is the second specific implementation of step S24.

Further, in step S24, the number of divided sections is greater than three. This is the third specific implementation of step S24.

Further, in the step S25, if it is the first measurement, the gain control value G is calculated_CurrTaking the initial value first interval R1 as the air interface signal power value P calculated by the last measurement_RfAnd judging the located section. This is a way of handling in special scenarios.

Further, in step S25, when the air interface signal power value P calculated by two consecutive measurements is obtained_RfAll the intervals are first intervals R1, and a flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is changed from a first section R1 to a second section R2, and the flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the first section R1 to a third section R3, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the second interval R2, and the last flow is maintained; the last time is the process a, and the current time is the process a; the last time is the process b, and the current time is the process b; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is changed from the second section R2 to the first section R1, and the flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the second section R2 to a third section R3, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are third intervals R3, and a flow b is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the third section R3 to the second section R2, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the third section R3 to the first section R1, and the flow a is adopted. This is the first specific implementation of step S25, corresponding to the first specific implementation of step S24.

Further, in step S25, when the air interface signal power value P calculated by two consecutive measurements is obtained_RfAll the intervals are first intervals R1, and a flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the first section R1 to the second section R2, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are second intervals R2, and a flow b is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the second section R2 to the first section R1, and the flow a is adopted. This is the second specific implementation of step S25, corresponding to the second specific implementation of step S24.

Further, the step S25 is changed to a step S25 a: the automatic gain control unit calculates the empty signal power value P according to the measurement_RfIn the interval, gain control value G calculated by the current measurement is calculated according to the process a_Curr(ii) a Wherein different Alpha filter coefficients are used in different intervals according to the magnitude of the signal average power measurement value; the Alpha filter coefficients employed for intervals explicitly containing valid signals are larger than the Alpha filter coefficients employed for intervals not explicitly containing valid signals. This is the third specific implementation of step S25, corresponding to the third specific implementation of step S24.

Further, the flow a in the step S25 specifically includes: firstly, obtaining the number N of effective resource blocks corresponding to the measured value according to the system information_RbThen calculating the air interface signal power value P according to the formula III_RfAfter 1 resource block is converted, Alpha filtering is carried out, and a signal power value P after the Alpha filtering is obtained_{Rf_Alpha}Finally, the signal power value P after Alpha filtering is carried out according to a formula II_{Rf_Alpha}And corresponding target signal power P_{Rf_Target}Comparing to obtain gain control value G calculated by the current measurement_Curr；

Formula III is P_{Rf_Alpha}＝(1-α)×P_{Rf_Alpha}＋α×P_Rf÷N_Rb(ii) a Wherein α represents the coefficients of an Alpha filter;

formula two is G_Curr＝G_Prev＋(P_{Rf_Target}－P_{Rf_Alpha}). This is a specific illustration of scheme a.

Optionally, in the flow a in step S25, the target signal power P in the formula two is due to the partial bandwidth BMP handover of the 5G NR system_{Rf_Target}Dynamically changing according to the maximum possible number of resource blocks of the signal. This is an alternative implementation of flow a.

Optionally, in the process a in step S25, the air interface signal power value P calculated in the current measurement is_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the increase exceeds a certain range, a relatively small value is used for replacing the air interface signal power value P calculated by the measurement_RfAnd participating in the Alpha filtering calculation shown in the formula III. This is another alternative implementation of flow a.

Optionally, in the process a in step S25, the air interface signal power value P calculated in the current measurement is_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the increase exceeds a certain magnitude, a relatively small Alpha filter coefficient Alpha is used to participate in the Alpha filter calculation shown in formula three. This is yet another alternative implementation of flow a.

Further, the flow b in the step S25 is to maintain the history value P of the Alpha filter output_{Rf_Alpha}Unchanged and according to the set maximum gain control value G_MaxAnd the gain control value G calculated from the last measurement_PrevThe comparison relationship between the gain control values G and G determines the gain control value G calculated by the measurement_Curr. This is a specific illustration of scheme a.

Further, the process b in the step S25 specifically includes: first, a maximum gain control value G is obtained_MaxThe value is set according to the power value P of the signal at the air interface_RfIs a first threshold value P_{Rf_TH1}When passing through the maximum gain control value G_MaxAfter adjustment, the signal sent to the demodulation end cannot generate saturation distortion, and the quantization signal-to-noise ratio is as large as possible; controlling the maximum gain value G_MaxAnd the gain control value G calculated from the last measurement_PrevComparing, and judging whether the difference value is less than or equal to the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev≤G_{Max_Diff_TH}Then directly using the maximum gain control value G_MaxGain control as a calculation of this measurementValue G_CurrI.e. G_Curr＝G_Max(ii) a When the difference between the two is larger than the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev＞G_{Max_Diff_TH}Then directly fluctuating the gain by the threshold value G_{Max_Diff_TH}Calculating the gain control value G calculated by the current measurement as the adjustment quantity of the current gain control value_CurrI.e. G_Curr＝G_Prev＋G_{Max_Diff_TH}. This is a further detailed description of scheme a.

Preferably, in step S26, the suitable time refers to a boundary position between the time slot measured this time and the next time slot. This is a preferred implementation of step S26.

The application also provides an automatic gain control device suitable for the 5G NR, which comprises an initialization unit, a measurement unit, a first calculation unit, a division unit, a second calculation unit and an effect unit. The initialization unit is used for enabling the mobile terminal to complete cell search and time-frequency synchronization and simultaneously obtain an initial value P of average power of signals_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}. The measurement unit is used for measuring by taking a time slot as a unit, counting the average power of signals corresponding to all OFDM symbols in the time slot, and obtaining the maximum value P in the average power_Max. The first calculation unit is used for calculating a gain control value G according to the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf. The dividing unit is used for judging the air interface signal power value P calculated by each measurement according to the set threshold value_RfThe section in which it is located. The second calculating unit is used for obtaining the air interface signal power value P measured and calculated by the dividing unit twice continuously_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr. The validation unit is used for calculating the gain control value G of the current measurement_CurrIs fed to a gain controller and controlled to be appropriateThe time is validated. The device counts the signal power by taking OFDM symbols as units, firstly judges the validity of the statistical signal, and calculates a new gain control value for automatic gain control when the statistical signal is valid, thereby avoiding the defects that the gain value is overlarge and data is saturated possibly under a specific scene.

The technical effect that this application obtained is: aiming at the problem that the traditional terminal automatic gain control method is used for a 5G NR terminal, the judgment of statistical signal effectiveness is firstly completed on the basis of counting the signal power by taking an OFDM symbol as a unit. And when the statistical value is considered to be effective, obtaining the number of effective resource blocks corresponding to the statistical signal by using the system information, and accordingly completing the updating of Alpha filtering and the calculation of the gain control value. When the statistic value is considered to be invalid, the historical value of the Alpha filtering is maintained unchanged, and a proper gain control value is calculated according to the relationship between the set maximum gain control value and the current gain control value. By the method, the tracking and the adjustment of the gain are automatically completed quickly and accurately, and the performance of the receiver is ensured.

Drawings

Fig. 1 is a schematic structural diagram of an automatic gain control apparatus in a conventional mobile terminal.

Fig. 2 is a flowchart of an automatic gain control method in a conventional mobile terminal.

Fig. 3 is a schematic diagram of measuring a received signal for automatic gain control in an LTE scenario.

Fig. 4 is a diagram of a 5G NR scenario one in which a received signal is measured for automatic gain control.

Fig. 5 is a schematic diagram of a second 5G NR scenario in which a received signal is measured for automatic gain control.

Fig. 6 is a schematic diagram of a 5G NR scenario three, where a received signal is measured for automatic gain control.

Fig. 7 is a flowchart of an automatic gain control method applied to 5G NR according to the present application.

Fig. 8 is a schematic diagram of implementation mode one (divided into three intervals) of step S24.

Fig. 9 is a schematic diagram of a first implementation manner (a variation of three intervals) of step S25.

Fig. 10 is a diagram illustrating the filtering result of the conventional Alpha filtering method in an extreme case.

Fig. 11 is a schematic diagram of a filtering result of the Alpha filtering method according to the present application in combination with the number of effective resource blocks in an extreme case.

Fig. 12 is a schematic diagram of implementation mode two (divided into two intervals) of step S24.

Fig. 13 is a schematic diagram of a second implementation (two-interval variation) of step S25.

FIG. 14 is a schematic diagram of one example of a method described herein.

Fig. 15 is a schematic structural diagram of an automatic gain control apparatus suitable for 5G NR according to the present application.

The reference numbers in the figures illustrate: 12 is a power detection unit; 14 is an automatic gain control unit; 16 is a gain controller; 21 is an initialization unit; 22 is a measuring unit; 23 is a calculation unit I; 24 is a dividing unit; 25 is a second calculating unit; 26 are the generating units.

Detailed Description

Referring to fig. 7, the method for controlling the automatic gain for 5G NR proposed by the present application includes the following steps.

Step S21: the mobile terminal completes cell search and time-frequency synchronization and obtains the initial value P of the average power of the signal_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}. The mobile terminal comprises a 5G NR mobile terminal.

Step S22: the power detection unit measures by taking a time slot as a unit, counts the average power of signals corresponding to all OFDM symbols in the time slot, and obtains the maximum value P in the average power_Max. Preferably, the measurement and statistics are periodically performed in units of time slots. In some scenarios, the measurements and statistics are in units of time slots, but are not performed periodically.

Step S23: automatic increasing deviceGain control value G calculated by control unit according to last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf. If the first measurement is carried out, the air interface signal power value P is calculated_RfThen, the gain control initial value G obtained in step S21 is used_InitGain control value G calculated as last measurement_Prev。

Step S24: the automatic gain control unit judges the air interface signal power value P calculated by each measurement according to the set threshold value_RfThe section in which it is located. The purpose of this step is to make a decision on the validity of the statistical signal for each measurement in step S22.

Step S25: the automatic gain control unit obtains the air interface signal power value P measured and calculated twice (called last time and current time) continuously_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr. If it is the first measurement, the gain control value G is calculated_CurrAt this time, the last measurement and calculation of the air interface signal power value P_RfIf there is no interval, the initial value first interval R1 is used as the air interface signal power value P calculated by the last measurement_RfAnd judging the located section.

Step S26: the automatic gain control unit calculates the gain control value G of the current measurement_CurrTo the gain controller and the control is effected at the appropriate time.

By repeating the steps S22 to S26, the method can quickly and accurately complete the tracking and adjustment of the gain automatically, and ensure the performance of the receiver.

Referring to fig. 8, the step S24 is implemented in the following manner, for example. Air interface signal power value P calculated in each measurement_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a first threshold value P in between_{Rf_TH1}And a second threshold value P_{Rf_TH2}First threshold value P_{Rf_TH1}Greater than a second threshold value P_{Rf_TH2}. Maximum possible value P_{Rf_Max}And a first threshold value P_{Rf_TH1}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the first interval R1, it indicates that the time slot measured this time must contain the valid signal sent by the base station. First threshold value P_{Rf_TH1}And a second threshold value P_{Rf_TH2}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the second interval R2, it indicates that the time slot of the current measurement may contain a valid signal sent by the base station. Second threshold value P_{Rf_TH2}With the minimum possible value P_{Rf_Min}In the third interval R3, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the third interval R3, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be measured by the power statistics. When the received signal power in the time slot is too low, the difference between the received signal power and the noise power is small, and the measurement result at this time is basically the same as the measurement result in the absence of the signal, so that the measurement result cannot be measured through power statistics. When the air interface signal power value P calculated by a certain measurement_RfJust equal to some threshold between two intervals, may belong to either of these two intervals. And a first threshold value P_{Rf_TH1}A second threshold value P_{Rf_TH2}May be fixed or may be dynamically varied according to the bandwidth of the actual received signal. The first threshold P may be dynamically changed according to the BandWidth of the radio frequency channel filter, for example, due to a partial BandWidth (BWP) handover of the 5G NR system_{Rf_TH1}A second threshold value P_{Rf_TH2}The value of (a).

For a 5G NR mobile terminal, the received signal bandwidth may range from 5MHz to 200 MHz. Taking 5MHz receiving bandwidth as an example, the corresponding threshold setting methods under other receiving bandwidths can be obtained in a similar derivation manner. If the mobile terminal works at normal temperature and the noise coefficient of the radio frequency of the terminal is 0, the power of the pure thermal noise converted to the air interface is-107 dBm, and the calculation mode is-174 + 10 × log₁₀(5×10⁶). A preferred threshold value is therefore set to: first threshold value P_{Rf_TH1}Is-87 dBm, second threshold value P_{Rf_TH2}Is-97 dBm, the minimum possible value P_{Rf_Min}Was-107 dBm.

Referring to fig. 9, the step S25 is implemented in the following manner, for example. When the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the first interval R1, and the process is a. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the first section R1 to the second section R2, and the flow a is followed. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the first section R1 to the third section R3, and the flow b is followed. When the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the second interval R2, and the previous flow is maintained. The last time is the process a, and the current time is the process a; the process b is performed the last time, and the process b is performed this time. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the second section R2 to the first section R1, and the flow a is followed. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the second section R2 to the third section R3, and the flow b is followed. When the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the third interval R3, and the flow b is followed. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the third section R3 to the second section R2, and the flow b is followed. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the third section R3 to the first section R1, and the flow a is followed.

The flow a represents a flow corresponding to the case where the statistical result of the current measurement is valid in step S22. The process a specifically comprises the following steps: firstly, obtaining the number N of effective Resource Blocks (RB) corresponding to the current measurement value according to the system information_Rb. Wherein a resource block refers to a resource combination that includes 12 subcarriers in the frequency domain and lasts for one slot. Then calculating the air interface signal power value P measured and calculated at this time according to a formula III_RfAfter the conversion to 1 resource block, Alpha filtering is carried out,and obtaining the signal power value P after the Alpha filtering_{Rf_Alpha}. Finally, according to formula two, the signal power value P after Alpha filtering_{Rf_Alpha}And corresponding target signal power P_{Rf_Target}Comparing to obtain gain control value G calculated by the current measurement_Curr. Alternatively, the target signal power P in equation two is due to partial bandwidth switching of the 5G NR system_{Rf_Target}It can be dynamically changed according to the maximum possible number of resource blocks of the signal.

Formula III is P_{Rf_Alpha}＝(1-α)×P_{Rf_Alpha}＋α×P_Rf÷N_Rb. Where Alpha represents the coefficients of the Alpha filter.

The flow a combines the number N of the effective resource blocks_RbAlpha filtering is performed, the principle of which is as follows. For a 5G NR mobile terminal, for example, when the system bandwidth is 100MHz and the subcarrier spacing is 30KHz, theoretically, the number of resource blocks corresponding to each OFDM symbol of a received signal may vary from 1 to 273, that is, the signal power difference caused by dynamic allocation of frequency domain resources may reach 24dB in two times before and after, and the calculation mode is 10 × log₁₀(273/1), which results in large jitter in the Alpha filtering result and affects the stability of the automatic gain control. One possible extreme is as follows: the mobile terminal is in the beginning because the downlink data volume is smaller, the base station distributes resources to the mobile terminal according to 1 resource block all the time; then at some point in time due to the amount of data in the burst, the base station quickly switches to 273 resource blocks to allocate resources to the mobile terminal with full bandwidth. Referring to the conventional Alpha filtering method shown in fig. 10, since the result corresponding to the history value of Alpha filtering is very small when hopping from 1 resource block to 273 resource blocks, in order to ensure that the adjusted signal is not saturated, if the time domain average effect of Alpha filtering is not considered, the result of Alpha filtering is increased by 24dB after the update of Alpha filtering is completed. Please refer to fig. 11, which shows the number N of combined effective resource blocks in the present application_RbBecause the air interface signal power value P is calculated by the measurement every time_RfBy scaling to 1 resource block for Alpha filtering, then Alpha filteringThe result will remain relatively stable at all times.

The flow b represents a corresponding flow when the statistical result of the current measurement is invalid in step S22. The process b specifically comprises the following steps: maintaining historical values P of Alpha filter outputs_{Rf_Alpha}Unchanged and according to the set maximum gain control value G_MaxAnd the gain control value G calculated from the last measurement_PrevThe comparison relationship between the gain control values G and G determines the gain control value G calculated by the measurement_Curr。

The air interface signal power value P measured and calculated at a time corresponding to the flow b_RfMay be at a first threshold value P_{Rf_TH1}And the minimum possible value P_{Rf_Min}As shown in fig. 8 and 9. So that a maximum gain control value G is obtained first_MaxThe value is set according to the power value P of the signal at the air interface_RfIs a first threshold value P_{Rf_TH1}When necessary, it is ensured that the maximum gain control value G is passed_MaxAfter adjustment, the signal sent to the demodulation end does not generate saturation distortion, and the quantization signal-to-noise ratio is as large as possible, so that even when the power of the received signal is at the power value P of the air interface signal_RfThe lower limit of (i.e. the minimum possible value of P)_{Rf_Min}Using this maximum gain control value G_MaxTheoretically, it can still be ensured that the quantized signal-to-noise ratio of the signal sent to the demodulation end is sufficiently high. The above conditions are easily satisfied in view of the current terminal design capability. After obtaining the maximum gain control value G_MaxThen, the process b can calculate the gain control value G calculated by the current measurement as follows_CurrThe description is as follows. Controlling the maximum gain value G_MaxAnd the gain control value G calculated from the last measurement_PrevComparing, and judging whether the difference value is less than or equal to the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev≤G_{Max_Diff_TH}Then directly using the maximum gain control value G_MaxGain control value G calculated as the present measurement_CurrI.e. G_Curr＝G_Max. Otherwise, when the difference value between the two is larger than the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev＞G_{Max_Diff_TH}Then directly fluctuating the gain by the threshold value G_{Max_Diff_TH}Calculating the gain control value G calculated by the current measurement as the adjustment quantity of the current gain control value_CurrI.e. G_Curr＝G_Prev＋G_{Max_Diff_TH}。

Alternatively, the step S22 is changed to a step S22 a: the power detection unit measures by taking a time slot as a unit, counts signal power corresponding to partial OFDM symbols in the time slot, and obtains the maximum value P in the signal power_Max. This may reduce hardware overhead and the amount of computation, but may result in the measurement result not being the actual maximum.

Alternatively, the step S22 is changed to a step S22 b: the power detection unit measures by taking a time slot as a unit, counts signal power corresponding to part or all OFDM symbols in the time slot, and obtains an average value P of the first k maximum values_MaxAnd k is a natural number greater than or equal to 2. For example, the signal powers corresponding to all OFDM symbols in the slot are sorted from large to small to obtain the average value of the previous k values. This can improve the accuracy of the measurement.

Referring to fig. 12, the step S24 is implemented in the following manner, for example. Air interface signal power value P calculated in each measurement_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a third threshold value P in between_{Rf_TH}. Maximum possible value P_{Rf_Max}And a third threshold value P_{Rf_TH}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the first interval R1, it indicates that the time slot measured this time must contain the valid signal sent by the base station. Third threshold value P_{Rf_TH}With the minimum possible value P_{Rf_Min}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the second interval R2, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be detected by the power statistics. When the air interface signal power value P calculated by a certain measurement_RfExactly equal to the third threshold value P_{Rf_TH}And may belong to either of these two intervals.And a third threshold value P_{Rf_TH}May be fixed or may be dynamically varied according to the bandwidth of the actual received signal.

Referring to fig. 13, the step S25 is implemented in, for example, the following manner two. When the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the first interval R1, and the process is a. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the first section R1 to the second section R2, and the flow b is followed. When the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the second interval R2, and the flow b is carried out. When the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the second section R2 to the first section R1, and the flow a is followed.

In step S24, the number of divided sections may be greater than three. Step S25 at this time is changed to step S25 a: the automatic gain control unit calculates the empty signal power value P according to the measurement_RfIn the interval, gain control value G calculated by the current measurement is calculated according to the process a_Curr. Wherein different Alpha filter coefficients are used in different intervals according to the magnitude of the average power measurement value of the signal. If the measured value of the average power of the current signal is larger in the interval definitely containing the effective signal, the value is larger; and if the average power measurement value of the current signal is smaller in an interval which does not definitely contain the effective signal, the average power measurement value is smaller.

Alternatively, in the process a, the air interface signal power value P calculated by the measurement is not used fixedly every time_RfAlpha filtering is performed. But instead some alternative values are used according to different scenarios. For example, when the air interface signal power value P calculated by this measurement_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the signal fluctuation exceeds a certain range (specific numerical value or proportion), in order to reduce the influence of the sudden signal fluctuation on the stability of the automatic gain control, a relatively small value is used for replacing the air interface signal power value P calculated by the measurement_RfAnd participating in the Alpha filtering calculation shown in the formula III.

Alternatively, in the flow a, Alpha filtering is not performed using a fixed Alpha filter coefficient α each time. But instead use dynamic Alpha filter coefficients Alpha according to different scenarios. For example, when the air interface signal power value P calculated by this measurement_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the amplitude is increased to exceed a certain amplitude (specific numerical value or proportion), in order to reduce the influence of the sudden signal fluctuation on the stability of the automatic gain control, a relatively small dynamic Alpha filter coefficient Alpha is used for participating in the calculation of Alpha filtering shown in the formula III, so that the occupation ratio of the measured signal is properly reduced.

Referring to fig. 14, a specific example of the method of the present application is shown. In this example, in the time slot n, the step S22 counts the signal power corresponding to the partial OFDM symbols in the time slot n, for example, counts 11 OFDM symbols numbered 0 to 10. Alternatively, the statistical range is smaller, for example, 10 OFDM symbols with statistical numbers 0 to 9. In step S26, for example, in the time slot corresponding to the OFDM symbol numbered 11 to 12 in the time slot n, the agc unit calculates the gain control value G for the current measurement_CurrSending the signal to a gain controller; and the automatic gain control unit controls the measurement to calculate the gain control value G at the boundary position of the time slot n and the next time slot n +1_CurrThis is a preferred example of "suitable time" described in step S26.

Referring to fig. 15, the automatic gain control apparatus for 5G NR provided by the present application includes an initialization unit 21, a measurement unit 22, a first calculation unit 23, a division unit 24, a second calculation unit 25, and an validation unit 26.

The initialization unit 21 is used to make the mobile terminal complete cell search and time-frequency synchronization, and obtain the initial value of average power P of signal_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}As Alpha filter outputHistory value P of_{Rf_Alpha}。

The measurement unit 22 is configured to measure in units of time slots, count signal average powers corresponding to all OFDM symbols in the time slot, and obtain a maximum value P therein_Max。

The first computing unit 23 is used for computing the gain control value G according to the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf. If the first measurement is carried out, the air interface signal power value P is calculated_RfUsing the gain control initial value G obtained by the initialization unit 21_InitGain control value G calculated as last measurement_Prev。

The dividing unit 24 is configured to determine the air interface signal power value P calculated by each measurement according to a set threshold_RfThe section in which the statistical signal is located, and thus the validity of the statistical signal is determined each time the measurement unit 22 measures the statistical signal.

The second calculating unit 25 is configured to obtain an air interface signal power value P measured and calculated by the dividing unit 24 twice (referred to as last time or this time) in succession_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr. If it is the first measurement, the gain control value G is calculated_CurrAt this time, the last measurement and calculation of the air interface signal power value P_RfIf there is no interval, the initial value first interval R1 is used as the air interface signal power value P calculated by the last measurement_RfAnd judging the located section.

The validation unit 26 is used for calculating the gain control value G of the current measurement_CurrTo the gain controller and the control is effected at the appropriate time.

The measurement unit 22, the first calculation unit 23, the division unit 24, the second calculation unit 25 and the validation unit 26 work continuously, so that the gain tracking and adjustment can be automatically completed quickly and accurately, and the performance of the receiver is ensured.

Referring to fig. 1 and fig. 15, the measurement unit 22 is implemented by the power detection unit 12, for example. The first calculation unit 23, the dividing unit 24, the second calculation unit 25 and the validation unit 26 are implemented, for example, by the automatic gain control unit 14.

The automatic gain control method and device suitable for the 5G NR provided by the application have the following beneficial effects.

Firstly, when all the OFDM symbols in the time slot do not contain effective signals, the scene is judged through logic, and the situation that the gain of automatic gain adjustment is too large and data is saturated due to misjudgment is prevented.

Secondly, when an effective signal exists in an OFDM symbol in the time slot, no matter where the effective signal exists, the baseband can accurately identify and measure the effective signal power, and automatic adjustment and updating of the gain can be faster.

Thirdly, for the scene definitely containing the effective signals, the number of effective resource blocks corresponding to the measured value is obtained by using the system information, and Alpha filtering is performed according to the number of effective resource blocks, so that severe waveforms of an Alpha filtering result caused by dynamic allocation of frequency domain resources are prevented, and the stability of automatic gain control is ensured.

Fourthly, for a scene definitely containing effective signals, according to the relationship between the signal power value after Alpha filtering and the historical value output by the Alpha filter, replacing the empty signal power value which is calculated by the current measurement participating in the Alpha filtering or dynamically changing the filter coefficient of the Alpha filter, thereby protecting the stability of automatic gain control.

Fifthly, for a scene which does not clearly contain an effective signal, a proper gain control value is calculated according to the relationship between the set maximum gain control value and the current gain control value.

The above are merely preferred embodiments of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automatic gain control method suitable for NR is characterized by comprising the following steps;

step S21: the mobile terminal completes cell search and time-frequency synchronization and obtains the initial value P of the average power of the signal_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}；

Step S22: the power detection unit measures by taking a time slot as a unit, counts the average power of signals corresponding to all OFDM symbols in the time slot, and obtains the maximum value P in the average power_Max；

Step S23: the automatic gain control unit calculates the gain control value G according to the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf；

Step S24: the automatic gain control unit judges the air interface signal power value P calculated by each measurement according to the set threshold value_RfThe section in which the user is located;

step S25: the automatic gain control unit obtains the empty signal power value P calculated by continuous two measurements_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr；

The process a is as follows: firstly, obtaining the number N of effective resource blocks corresponding to the measured value according to the system information_RbThen calculating the air interface signal power value P according to the formula III_RfAfter 1 resource block is converted, Alpha filtering is carried out, and a signal power value P after the Alpha filtering is obtained_{Rf_Alpha}Finally, the signal power value P after Alpha filtering is carried out according to a formula II_{Rf_Alpha}And corresponding target signal power P_{Rf_Target}Comparing to obtain gain control value G calculated by the current measurement_Curr；

formula two is G_Curr＝G_Prev＋(P_{Rf_Target}－P_{Rf_Alpha})；

The flow b is to maintain the historical value P of the output of the Alpha filter_{Rf_Alpha}Unchanged and according to the set maximum gain control value G_MaxAnd the gain control value G calculated from the last measurement_PrevThe comparison relationship between the gain control values G and G determines the gain control value G calculated by the measurement_Curr；

Step S26: the automatic gain control unit calculates the gain control value G of the current measurement_CurrSending the data to a gain controller, and controlling to be effective at a proper time; the proper time refers to the boundary position of the time slot measured this time and the next time slot.

2. The method of claim 1, wherein the step S22 is modified to a step S22 a: the power detection unit measures by taking a time slot as a unit, counts signal power corresponding to partial OFDM symbols in the time slot, and obtains the maximum value P in the signal power_Max。

3. The method of claim 1, wherein the step S22 is modified to a step S22 b: the power detection unit measures by taking a time slot as a unit, counts signal power corresponding to part or all OFDM symbols in the time slot, and obtains an average value P of the first k maximum values_MaxAnd k is a natural number greater than or equal to 2.

4. The method of any one of claims 1 to 3, wherein in the steps S22, S22a and S22b, the measurement and statistics are periodically performed in units of time slots.

5. The method of claim 1, wherein in step S23, if it is the first measurement, the air interface signal power value P is calculated_RfThen, thenUsing the initial value G of gain control obtained in step S21_InitGain control value G calculated as last measurement_Prev。

6. The method of claim 1, wherein in step S24, the air interface signal power value P calculated in each measurement is used_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a first threshold value P in between_{Rf_TH1}And a second threshold value P_{Rf_TH2}First threshold value P_{Rf_TH1}Greater than a second threshold value P_{Rf_TH2}(ii) a Maximum possible value P_{Rf_Max}And a first threshold value P_{Rf_TH1}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into the first interval R1, the time slot of the current measurement necessarily contains the effective signal sent by the base station; first threshold value P_{Rf_TH1}And a second threshold value P_{Rf_TH2}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into a second interval R2, the time slot of the current measurement possibly contains a valid signal sent by the base station; second threshold value P_{Rf_TH2}With the minimum possible value P_{Rf_Min}In the third interval R3, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the third interval R3, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be measured by the power statistics.

7. The method of claim 6, wherein in the step S24, the first threshold P is dynamically changed according to the bandwidth of the RF channel filter due to the BWP switching of the partial bandwidth of the 5G NR system_{Rf_TH1}A second threshold value P_{Rf_TH2}The value of (a).

8. The method of claim 1, wherein in step S24, the air interface signal power value P calculated in each measurement is used_RfIs the minimum possible value of P_{Rf_Min}With the maximum possible value P_{Rf_Max}Set a third threshold value P in between_{Rf_TH}(ii) a Maximum possible value P_{Rf_Max}And a third threshold value P_{Rf_TH}In between is a first interval R1, the air interface signal power value P calculated by each measurement_RfIf the time slot falls into the first interval R1, the time slot of the current measurement necessarily contains the effective signal sent by the base station; third threshold value P_{Rf_TH}With the minimum possible value P_{Rf_Min}In the second interval R2, the air interface signal power value P calculated by each measurement_RfIf the time slot falls in the second interval R2, it indicates that the time slot measured this time does not contain a valid signal sent by the base station, or the received signal power in the time slot is too low to be detected by the power statistics.

9. The method of claim 1, wherein in step S24, the number of divided sections is greater than three.

10. The method of claim 1, wherein in step S25, if it is the first measurement, the gain control value G is calculated_CurrTaking the initial value first interval R1 as the air interface signal power value P calculated by the last measurement_RfAnd judging the located section.

11. The method of claim 6, wherein in step S25, when the calculated air interface signal power value P is measured twice consecutively, the method is characterized in that_RfAll the intervals are first intervals R1, and a flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is changed from a first section R1 to a second section R2, and the flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the first section R1 to a third section R3, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are the second interval R2, maintainA first process; the last time is the process a, and the current time is the process a; the last time is the process b, and the current time is the process b; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is changed from the second section R2 to the first section R1, and the flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the second section R2 to a third section R3, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are third intervals R3, and a flow b is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the third section R3 to the second section R2, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the third section R3 to the first section R1, and the flow a is adopted.

12. The method as claimed in claim 8, wherein in step S25, the calculated air interface signal power value P is measured twice consecutively_RfAll the intervals are first intervals R1, and a flow a is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfChanging the section from the first section R1 to the second section R2, and adopting the flow b; when the air interface signal power value P is measured and calculated twice continuously_RfAll the intervals are second intervals R2, and a flow b is adopted; when the air interface signal power value P is measured and calculated twice continuously_RfThe change of the section is from the second section R2 to the first section R1, and the flow a is adopted.

13. The method of claim 9, wherein the step S25 is modified to a step S25 a: the automatic gain control unit calculates the empty signal power value P according to the measurement_RfIn the interval, gain control value G calculated by the current measurement is calculated according to the process a_Curr(ii) a Wherein different intervals are used differently according to the magnitude of the signal average power measurement valueAlpha filter coefficients of (a); the Alpha filter coefficients employed for intervals explicitly containing valid signals are larger than the Alpha filter coefficients employed for intervals not explicitly containing valid signals.

14. The method of claim 1, wherein in the process a of step S25, the target signal power P in the formula two is obtained due to the partial bandwidth BWP switching of the 5G NR system_{Rf_Target}Dynamically changing according to the maximum possible number of resource blocks of the signal.

15. The method according to claim 1, wherein in the process a of step S25, when the air interface signal power value P is calculated by the current measurement, the method is characterized in that_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the increase exceeds a certain range, a relatively small value is used for replacing the air interface signal power value P calculated by the measurement_RfAnd participating in the Alpha filtering calculation shown in the formula III.

16. The method according to claim 1, wherein in the process a of step S25, when the air interface signal power value P is calculated by the current measurement, the method is characterized in that_RfAnd the number N of effective resource blocks_RbRatio P of_Rf/N_RbHistorical value P relative to Alpha filter output_{Rf_Alpha}When the increase exceeds a certain magnitude, a relatively small Alpha filter coefficient Alpha is used to participate in the Alpha filter calculation shown in formula three.

17. The method of claim 1, wherein the process b in the step S25 is specifically as follows: first, a maximum gain control value G is obtained_MaxThe value is set according to the power value P of the signal at the air interface_RfIs a first threshold value P_{Rf_TH1}When passing through the maximum gain control value G_MaxAfter adjustment, the signal sent to the demodulation end cannot generate saturation distortion, and the quantization signal-to-noise ratio is as large as possible; controlling the maximum gain value G_MaxAnd the gain control value G calculated from the last measurement_PrevComparing, and judging whether the difference value is less than or equal to the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev≤G_{Max_Diff_TH}Then directly using the maximum gain control value G_MaxGain control value G calculated as the present measurement_CurrI.e. G_Curr＝G_Max(ii) a When the difference between the two is larger than the gain fluctuation threshold G_{Max_Diff_TH}When is at G_Max－G_Prev＞G_{Max_Diff_TH}Then directly fluctuating the gain by the threshold value G_{Max_Diff_TH}Calculating the gain control value G calculated by the current measurement as the adjustment quantity of the current gain control value_CurrI.e. G_Curr＝G_Prev＋G_{Max_Diff_TH}。

18. An automatic gain control device suitable for NR is characterized by comprising an initialization unit, a measurement unit, a first calculation unit, a division unit, a second calculation unit and an effective unit;

the initialization unit is used for enabling the mobile terminal to complete cell search and time-frequency synchronization and simultaneously obtain an initial value P of average power of signals_InitAnd a gain control initial value G_InitAnd calculating to obtain the initial value P of the air interface signal power according to the two values_{Rf_Init}Historical value P as Alpha filter output_{Rf_Alpha}；

The measurement unit is used for measuring by taking a time slot as a unit, counting the average power of signals corresponding to all OFDM symbols in the time slot, and obtaining the maximum value P in the average power_Max；

The first calculation unit is used for calculating a gain control value G according to the last measurement_PrevAnd statistical result P of this measurement_MaxCalculating to obtain the air interface signal power value P calculated by the current measurement_Rf；

The dividing unit is used for judging the air interface signal power calculated by each measurement according to a set threshold valueValue P_RfThe section in which the user is located;

the second calculating unit is used for obtaining the air interface signal power value P measured and calculated by the dividing unit twice continuously_RfObtaining the gain control value G calculated by the current measurement according to the process a or the process b according to the change condition of the section in which the gain control value G is positioned_Curr；

formula two is G_Curr＝G_Prev＋(P_{Rf_Target}－P_{Rf_Alpha})；

The validation unit is used for calculating the gain control value G of the current measurement_CurrSending the data to a gain controller, and controlling to be effective at a proper time; the proper time refers to the boundary position of the time slot measured this time and the next time slot.