KR20070069824A - Method for automatic gain control in wireless telecommunication terminal - Google Patents

Abstract

An automatic gain control method for performing a wireless communication terminal is provided to solve the problem that a correction failure rate is increased by erroneously setting the tolerance range of input feature values. Input feature values of a baseband module and the allowable margin of error of the feature value are set. Power is measured after an radio frequency(RF) signal is converted into a digital signal. The digital signal is converted into an analog signal after a gain value of the digital signal is set according the measured power value. A gain of the RF signal is adjusted according to a gain value of the converted analog signal. The allowable margin of the error is changed to adjust a gain if normal gain control fails.

Description

Method for Automatic Gain Control in wireless telecommunication terminal

1 is a configuration diagram of an embodiment of a receiver of a conventional wireless communication terminal;

2 is a diagram illustrating an embodiment of a general automatic gain control;

3 is a flowchart illustrating an automatic gain control method in a wireless communication terminal according to the present invention.

* Explanation of symbols for the main parts of the drawings

11: RF receiver 12: baseband unit

121: analog to digital converter 122: power meter

123: gain control controller 124: digital to analog converter

The present invention relates to an automatic gain control method in a wireless communication terminal, and more particularly, to satisfy 3GPP TS 45.008, subclause 8.1.2, 3GPP TS 45.005, subclause 6.2 and 3GPP TS 51.010-1 subclause 21.1.2. The present invention relates to an automatic gain control method in a wireless communication terminal for minimizing a correction failure rate by changing an error range in the automatic gain.

In the present invention, the wireless communication terminal is a mobile communication terminal, a personal communication service (PCS) terminal, a personal digital assistant (PDA), a smartphone, a next generation mobile communication (IMT-2000) terminal, a wireless LAN terminal, a GSM (Global System for Mobile communication) It refers to a portable wireless communication terminal that can transmit / receive voice, text and video data through wireless communication.

Based on the I / Q (In phase / Quadrature phase) signal with a constant level of intensity (-16 dBm) with respect to the intensity (-10 dBm to -110 dBm) of the RF (Radio Frequency) signal received through the antenna at the wireless communication terminal A series of processes of mixing the appropriate gain values for each signal strength so as to be provided to the band part is called automatic gain control (AGC). This is as shown in FIG.

Auto gain control can sometimes be prevented due to variations in the part characteristics of RF receiver components. In particular, this can be a big problem when mass production of a large number of wireless communication terminals. In actual production, the RF receiver parts are considered defective, and the rework of replacing the RF parts is a certain ratio.

However, even if the characteristics of the RF component are not as good as normal, 3GPP (3rd Generation Partnership Projects) TS 45.008, subclause 8.1.2, 3GPP TS 45.005, subclause 6.2 and 3GPP TS 51.010-1 subclause If 21.1.2 is met, it does not need to be considered bad.

Therefore, automatic gain control is also performed for RF receiver parts that have less characteristics than the normal parts, and satisfy 3GPP TS 45.008, subclause 8.1.2, 3GPP TS 45.005, subclause 6.2 and 3GPP TS 51.010-1 subclause 21.1.2. There is a need for a method that allows correction within a range.

1 is a configuration diagram of an embodiment of a receiver of a conventional wireless communication terminal.

As shown in FIG. 1, the receiver of the conventional wireless communication terminal includes: an RF receiver 11 for adjusting a gain of an RF signal received through an antenna according to an input characteristic value of the baseband unit 12, and And a base bad part 12 for controlling gain adjustment of the RF receiver 11.

Here, the baseband unit 12, the analog / digital converter 121 for converting the RF signal received by the RF receiver 11 to digital, the power of the digital signal converted by the analog / digital converter 121 The power meter 122 for measuring the power, the gain control controller 123 for setting the gain value of the digital signal according to the power value measured by the power meter 122, and the gain control controller 123 Digital to analog converter 124 for converting one gain value to analog.

In addition, the RF receiver 11 includes a gain adjuster 111 for adjusting the gain of the RF signal according to the analog gain value received from the digital-to-analog converter 124. In this case, the signal provided to the baseband unit 12 by the gain adjuster 111 is an I / Q signal.

In more detail, the signal received by the RF receiver 11 enters the input of the base band unit 12. The signal coming into the input of the baseband 12 is converted into a digital signal through the analog-to-digital converter 121 of the analog baseband chip, and the magnitude is measured by the power meter 122 of the digital baseband chip. The magnitude of the measured signal is calculated by the gain control controller 123 as a reception level (Rx Level). At this time, the gain is obtained from the obtained reception level, and the gain value necessary for the correction is sent to the RF receiver 11 through the analog baseband chip, and the RF receiver adjusts the gain to provide a signal having a desired size to the baseband unit 12. .

In addition, the RF receiver 11 further includes an antenna switch, a SAW filter, and an RF receiver, and the baseband unit 12 includes an analog baseband chip and a digital baseband chip, but may obscure the gist of the present invention. I will not explain in detail.

Here, the RF receiver can adjust the gain in a low noise amplifier (LNA), an analog programmable gain amplifier, and a digital programmable gain amplifier. Only the digital programmable gain is adjusted, not the gain of the amplifier and analog programmable amplifier.

On the other hand, the automatic gain control method in the conventional wireless communication terminal, first set the frequency band and channel, the set point (Set point), which is the size of a certain input signal to be corrected, the upper limit limit of the correction, the lower limit range and Define the default AGC DAC Table.

Then, the automatic gain adjustment is set at 4dB intervals from -10dBm to -110dBm with respect to the input power received by the RF receiver 11. At this time, correction is performed only when the input power of the RF receiver 11 is lower than the set value (-16 dBm). This is because the ordinary RF receiver 111 does not provide negative gain.

Therefore, the input power that first starts calibration starts at a power level of -18 dBm or less.

Looking at the gain adjustment process, first, the digital gain value for the corresponding input power is retrieved through [Table 1] below, and the power is measured when the retrieved digital gain value is applied. If the measured power value is greater than the upper limit level, the digital gain value is decreased. If the measured power value is less than the lower limit level, the digital gain value is increased.

When the digital gain value is satisfied within the upper / lower limit levels, a gain table is constructed and a series of steps to adjust the gain for the next input power are repeated until the input power reaches -110 dBm and then the AGC for each input power. Calibrate the DAC.

In the conventional wireless communication terminal, the gain of the electric field (± 2dBm) and the weak field (± 4dB) are described in the GSM specification in controlling gain according to the following [Table 1]. By setting the allowable range of the input characteristic value of the baseband unit 12 to ± 0.5 dBm, there is a problem of increasing the correction failure rate.

Here, 'LNA Gain' is the gain of the low noise amplifier, 'Analog Gain' is the gain of the analog programmable amplifier, 'Digital Gain' is the gain of the digital programmable amplifier.

At this time, 'Digital Gain' for input power of -22dBm and -38dBm is 2 and 1, respectively. If you use the gain less than 0 to adjust the setting value (-16dBm) at -22dBm and -38dBm due to the variation of RF receiver unit characteristics, desired gain adjustment is impossible. In addition, when the automatic gain is adjusted for weak power with an input power of -102 dBm or less, the accuracy of correction may be decreased, and the correction may not be performed within the upper and lower limits of the set value due to the variation of the RF receiver characteristic.

In actual mass production, the automatic gain adjustment failure occurs most frequently along with the transmission power correction failure, and in most cases, the RF receiver is replaced by considering the RF receiver as defective, resulting in inefficient operation of work time and manpower.

The present invention has been proposed to solve the above problems, and automatically changes the error range within a range that satisfies 3GPP TS 45.008, subclause 8.1.2, 3GPP TS 45.005, subclause 6.2 and 3GPP TS 51.010-1 subclause 21.1.2. It is an object of the present invention to provide an automatic gain control method in a wireless communication terminal for minimizing a correction failure rate by adjusting gain.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

According to an aspect of the present invention, there is provided a method for controlling automatic gain in a wireless communication terminal, the method comprising: setting an input characteristic value of a baseband unit and an error range of the input characteristic value; Measuring power after converting the RF signal received through the antenna into digital; Setting a gain value of the digital signal according to the measured power value and converting the analog signal into an analog signal; And adjusting the gain of the RF signal according to the converted analog gain value. If the gain adjustment fails as a result of the gain adjustment, the gain is adjusted by changing the error range.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating an automatic gain control method in a wireless communication terminal according to the present invention.

First, a frequency band and a channel are set, and a constant input power level (-16dBm) provided in the base band part, upper / lower limit ranges, a default AGC DAC table, and a reception level error table as shown in [Table 2] below are defined (301). , 302).

Thereafter, the automatic gain adjustment is performed at intervals of 4 dB from -10 dBm to -110 dBm with respect to the input power received through the RF unit of the terminal (303). In this case, the RF input power level is corrected only at a level lower than a set point (−16 dBm) (304). This is because the average RF receiver does not provide negative gain. Therefore, the input power level at which the first correction starts is at a level of -18 dBm or less.

Subsequently, a gain value for the corresponding input power is read out and the power is measured when the gain value is applied (305, 306).

If the measured power level when the gain value is applied satisfies the set value (± 0.5dB) and the upper / lower limit level, the AGC DAC table and the gain table are configured and the gain for the next RF input power level is adjusted (307, 309).

The process "308" is as follows.

If the set value (± 0.5dB) and the upper / lower limit level are not satisfied, increase or decrease the gain value up to three times to check whether it is within the upper / lower limit level. Configure the DAC table and gain table and adjust the gain for the next RF input power level.

If the measured power level does not fall within the set value (± 0.5dB) even after increasing or decreasing the gain value up to three times, set a new upper / lower limit level. The new upper and lower levels are as follows.

Upper Limint = Set point + (A + 0.2),

Lower Limint = Set point-(A + 0.2)

Here, A is the absolute value of the difference between the set value and the power level measured when the AGC DAC is applied.

(A = ｜ Set point-Power level measured when AGC DAC is applied ｜)

The reason for adding 0.2 dB to A is to have a 0.2 dB margin.

Check if the measured power level satisfies the error level for the corresponding RF input in the new high / low limit level and the reception level error table at the same time. When these two conditions are met, the AGC DAC table and gain table are configured and automatic gain adjustment is made for the next RF input power level. Repeat this sequence of steps to find the AGC DAC for each RF input power level from -10dBm to -110dBm.

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, the present invention is calculated by applying a new upper / lower limit range when the case that the correction can not be achieved by the existing automatic gain adjustment method and the new phase, only in the range that satisfies 3GPP TS 51.010-1 subclause 21.1.2, By setting a lower limit, the accuracy of the calibration can be improved and the failure rate can be minimized.

In addition, the present invention can minimize the failure rate of the automatic gain adjustment, which is one of the most frequently generated defects in the mass production of the terminal, and can more efficiently manage the work force, time, and cost of replacing the RF receiver for repair.

Claims (4)

In the automatic gain control method in a wireless communication terminal, Setting an input characteristic value of the baseband unit and an error range of the input characteristic value; Measuring power after converting the RF signal received through the antenna into digital; Setting a gain value of the digital signal according to the measured power value and converting the analog signal into an analog signal; And Adjusting the gain of the RF signal according to the converted analog gain value, And controlling gain by changing the error range if gain control fails normally. The method of claim 1, The error range is, Automatic gain control method in a wireless communication terminal, characterized in that for changing by ± 0.2 intervals. The method according to claim 1 or 2, The error range is, A strong electric field having an input power of -10 dBm to -86 dBm allows up to ± 2 of the input characteristic value, and a weak electric field having an input power of -90 dBm to -110 dBm allows up to ± 4 of the input gain value. Automatic gain control method in communication terminal. The method of claim 3, wherein The wireless communication terminal, Automatic gain control method in a wireless communication terminal, characterized in that the GSM (Global System for Mobile communication) terminal.

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