KR100591336B1 - Gain Control Method for Mobile Telecommunication Terminal - Google Patents

Abstract

The present invention relates to a gain adjustment method of a mobile communication terminal that can significantly reduce the generation time of a lookup table for adjusting the output of an automatic gain controller having a nonlinear characteristic to a linear characteristic. Are classified into several levels, and when a transmission signal is transmitted to each power level through an antenna, a PDM value applied to the automatic gain controller is detected or calculated, respectively, and a lookup for each power level and a corresponding PDM value ( a first step of generating a look-up table and a second step of searching the lookup table for a PDM value corresponding to the output-determined value when the output power value of the output-determined transmission signal is different from the output power value currently being output. And a third step of converting the PDM signal according to the retrieved PDM value to the automatic gain controller. In addition to significantly shortening the execution time for generating a label, the linear characteristics can be obtained more quickly, thereby improving the reception sensitivity of the terminal and reducing the power consumption. It can be effective.

Automatic Gain Control, Lookup Table, PDM, Transmitter

Description

 Gain control method for mobile communication terminal {Gain Control Method for Mobile Telecommunication Terminal}             

1 is a flowchart illustrating a process of generating a lookup table in which power levels and corresponding PDM values are stored in a gain adjustment method of a mobile terminal according to the prior art;

2 is a block diagram showing a transmitting end of a mobile communication terminal according to the present invention;

3 is a flowchart illustrating a process of generating a lookup table in which power levels and corresponding PDM values are stored in a gain adjustment method of a mobile communication terminal according to the present invention;

4 is a flowchart illustrating a gain adjustment method of a mobile communication terminal according to the present invention.

<Explanation of symbols on main parts of the drawings>

11: MSM 12: Auto Gain Controller

14: power amplifier 15: duplexer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gain adjustment method of a mobile communication terminal, and in particular, a gain adjustment method of a mobile communication terminal that can greatly shorten the generation time of a lookup table for adjusting the output of an automatic gain controller having a nonlinear characteristic to a linear characteristic. It is about.

In designing a code division multiple access (CDMA) system, it is important to maximize the number of users who can talk simultaneously on a given bandwidth. If the transmission power of the mobile communication terminal received by the base station is low, the bit error rate is too high to expect a good quality call. If the reception power received by the base station is high, the call quality is improved, but other mobile communication using the same channel is used. As the interference to the terminal increases, the call quality of other mobile communication terminals is greatly reduced.

The signal strength received from the CDMA mobile terminal enables the terminal to adjust its own transmit power. If the received signal strength is high, the transmit power of the terminal is low, which means that the terminal is located close to the base station or path loss is reduced. It means very little.

On the other hand, the terminal transmits at low power when located in close proximity to the base station, and high power when located at a long distance to equalize the received power of all terminal transmission signals reaching the base station.

To do this, an automatic gain control (AGC) amplifier should be used at the transmitting end of the terminal, which has a gain control range of about 80 dBm by adjusting the transmission gain with voltage, and provides a high power transmission signal through the gain control voltage. Will be created.

  In this case, the automatic gain controller has a non-linear output characteristic that cannot predict an increase or decrease in the output voltage since the output does not increase or decrease in proportion to the increase or decrease of the voltage adjusting the output in a constant step.

1 is a flowchart illustrating a process of generating a lookup table in which power levels and corresponding pulse density modulation (PDM) values are stored in a gain adjustment method of a mobile communication terminal according to the prior art;

In order for the automatic gain controller to have a linear output characteristic, each PDM value of a mobile station modem (MSM) controlling gain adjustment of the automatic gain controller and each output power value of a transmission signal according to each PDM value are stored together. A table is generated, and the gain of the automatic gain controller is adjusted according to the generated table.

That is, when 32 power levels are set in 2.66 dBm steps with 82.46 dBm power levels from -55 dBm to 27.46 dBm (S1), the PDM of the MSM corresponding to -55 dBm corresponding to the first level among the power levels Detects the value and sequentially detects the PDM value corresponding to each level (S2 to S4).

After detecting the 32nd PDM value corresponding to 27.46dBm after the above process, a table is generated according to each power level and PDM value corresponding to the level, and the gain of the automatic gain controller is referred to by referring to the generated table. Will be adjusted. (S5, S6)

However, the gain adjustment method of the mobile communication terminal according to the prior art operating as described above needs to repeat the detection operation 32 times in order to detect all the PDM values for the 32 levels in generating the table. There is a problem that it takes considerable time to generate.

In addition, since the automatic gain controller has a non-linear output characteristic until the table is generated, there is a limit in improving reception signal sensitivity or controlling transmission power.

The present invention has been made to solve the above-described problems of the prior art, and when generating a look-up table for gain adjustment, detects a PDM value corresponding to some level among a plurality of power levels, and detects the detected value. Is applied to a specific algorithm to calculate a PDM value corresponding to the remaining power level, a method of adjusting a gain of a mobile communication terminal to greatly shorten the generation time of the table.

The gain adjustment method of the mobile communication terminal according to the present invention for solving the above problems is to classify the total gain power of the automatic gain controller to a level of several levels, and when the transmission signal is transmitted to each power level through the antenna A first step of detecting or calculating a PDM value applied to the gain controller to generate a look-up table for each power level and a corresponding PDM value, and output power value and current output of the output-determined transmission signal. And a second step of retrieving a PDM value corresponding to the determined output value from the lookup table when the output power value is different, and a third step of converting the PDM signal according to the retrieved PDM value to the automatic gain controller. Characterized in that made.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. 2 is a block diagram showing a transmitting end of a mobile communication terminal according to the present invention.

First, the MS of the mobile communication terminal according to the present invention detects a reception level of a signal received through an antenna and outputs an IF (Intermediate Frequency) signal and an automatic gain control signal corresponding thereto. And an automatic gain controller 12 for adjusting the gain of the IF signal according to the automatic gain control signal output from the MSM 11, and amplifying the signal output from the automatic gain controller by the transmission power. And a power amplifier 14.

The up-mixer 13 receives the IF signal from the automatic gain controller 12 and converts the IF signal into an RF signal, and then applies the power amplifier 14 to the power amplifier 14 and the power amplifier 14. It comprises a duplexer (Duplexer) 15 for transmitting the output RF signal to the base station via the antenna (N).

The MSM 11 controls the overall operation of the mobile communication terminal by generating and transmitting a control signal, and after receiving the RF signal from the base station, calculates a transmission power value of the RF signal according to the reception level of the received RF signal. Then, a PDM control signal corresponding to the calculated transmission power is applied to the automatic gain controller 12.

The automatic gain controller 12 amplifies the IF signal according to the gain determined by the PDM control signal received from the MSM 11.

The duplexer 15 transmits the RF signal output from the power amplifier 14 to the base station through the antenna N.

Meanwhile, the MSM 11 calculates the output power of each signal output through the antenna N and the PDM value applied to the automatic gain controller 12 for the linear characteristic of the automatic gain controller 12. In order to store the look-up table, the method of generating the look-up table will be described below.

3 is a flowchart illustrating a process of generating a lookup table in which power levels and corresponding PDM values are stored in a gain adjustment method of a mobile communication terminal according to the present invention.

First, 32 levels of power are classified into 2.66 dBm in units of -66 dBm to 27.46 dBm.

When the transmission signal corresponding to -55dBm, which is the first step, is transmitted through the antenna, the PDM value applied from the MSM to the automatic gain controller is detected. In the same manner as above, -39.40dBm (7th) and -23.08dBm PDM values corresponding to (13th), -7.12dBm (19th), 8.84dBm (25th), 24.8dBm (31st), and 27.46dBm (32th) are detected respectively (S12).

PDM values corresponding to the remaining power levels are calculated using the respective PDM values corresponding to the detected 1, 7, 13, 19, 25, 31, and 32 th power levels. In this case, an algorithm for calculating each PDM value uses an interpolation algorithm, and for example, a function for calculating the second to sixth PDM values using the first and seventh PDM values is as follows. )

for (n = 0; n <5; n ++) {

                  (n + 2) th PDM = {(7th PDM-1st PDM) * n}-1st PDM

                   }

The second to sixth PDM values may be calculated using the function as described above, and the PDM values for the remaining power levels among the 32 power levels may be calculated in a similar manner. A table for gain adjustment of the automatic gain controller may be generated based on the calculated PDM value.

In this case, the table is stored in a nonvolatile region of a flash memory built in the MSM, and the MSM retrieves a PDM value corresponding to each transmission power from the table and transmits a corresponding PDM signal to the automatic gain controller. (S14)

Looking at the gain control operation of the present invention as described above are as follows. 4 is a flowchart illustrating a gain adjustment method of a mobile communication terminal according to the present invention.

 First, as described with reference to FIG. 3, the total gain power of the automatic gain controller is classified into several levels, and the PDM value applied to the automatic gain controller when the transmission signal is transmitted to each power level through an antenna is described. Each detection or calculation is performed to generate a look-up table for each power level and a corresponding PDM value.

When the output power value of the output determined transmission signal is compared with the output power value currently being output, the PDM value corresponding to the output power value of the output determined signal is searched for in the lookup table (S20, S30).

A PDM signal is generated based on the found PDM value, and the generated PDM signal is converted into a DC voltage and applied to the automatic gain controller (S40).

The automatic gain controller adjusts the gain according to the received DC voltage, amplifies the received IF signal according to the adjusted gain, and transfers the received IF signal to the up-mixer.

As described above, the gain adjusting method of the mobile communication terminal according to the present invention has been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and PDM values for some power levels are not shown. The technical idea of the present invention to quickly generate a look-up table for an automatic gain controller by detecting and calculating PDM values for other power levels by interpolation is provided to those skilled in the art within the scope of protection. It can be easily applied by.

The gain adjustment method of the mobile communication terminal according to the present invention configured as described above detects only a part of data through an operation in the process of generating a lookup table having a linear gain characteristic, and a specific algorithm for other data. By calculating using, the execution time for generating the table is greatly shortened.

In addition, accordingly, since the linear characteristics can be obtained more quickly, not only the reception sensitivity of the terminal can be improved, but also the power consumption can be reduced, thereby greatly improving the reliability of the user.

Claims (5)

The total gain power of the automatic gain controller is classified into several levels, and when a transmission signal is transmitted to each power level through an antenna, the PDM value applied to the automatic gain controller is detected or calculated, respectively, to determine each power level and its corresponding value. Generating a look-up table for the PDM value; A second step of searching for a PDM value corresponding to the output determined value in the lookup table when the output power value of the output determined transmission signal and the output power value currently being output are different; And a third step of converting the PDM signal according to the retrieved PDM value and transmitting the PDM signal to the automatic gain controller. The method of claim 1, The first step includes: detecting a PDM value corresponding to a part of the plurality of power levels; And a second step of calculating a PDM value corresponding to the remaining power level by using the detected PDM value. The method of claim 2, The second process is a gain adjustment method of a mobile communication terminal, characterized in that for calculating the PDM value using an interpolation algorithm. The method of claim 3, wherein  The first process classifies the total gain power into 32 power levels and detects PDM values corresponding to 1, 7, 13, 19, 25, 31, and 32 power levels. Gain adjustment method. The method of claim 1, And the look-up table is stored in a non-volatile area of a flash memory.

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