KR100483287B1 - Average power level search apparatus and method in system using multi look up table - Google Patents

Abstract

The present invention relates to an apparatus and method for searching average power level in a system using multiple lookup tables.

The present invention relates to an average power input that reads the current average power value P _avg for the input I and Q signals when detecting the level of the current average power value P _avg of the input signal using the multiple lookup table. ; An average power fluctuation detector for determining an average power fluctuation value with respect to the current average power value P _avg using the current average power value P _avg and an input previous average power value P _level ; A change allowance range determiner for determining whether the average power change value is within a predetermined allowable range and outputting a change allowance range determination signal; According to the variable allowable range determination signal, the previously stored previous lookup index signal LUT is output as the current lookup index signal LUT_index or the current lookup index signal LUT_index to which the level of the current average power value P _avg belongs. ), And output the current lookup index signal (LUT_index) as the previous lookup index signal (LUT) and change its current average power value (P _avg ) to a previous average power value (P _level ). And a current lookup index signal outputted to the variation detector and a previous average power value generator.

Therefore, when the present invention detects the level of the current average power value P _avg of the input signal using the multiple lookup table, whether the average power fluctuation value according to the current average power value P _avg falls within a predetermined allowable range. If it is determined whether the average power variation is within a predetermined allowable range, the previously stored lookup index signal (LUT) is output to maintain the previous lookup table, and the average power variation is out of the predetermined allowable range. Only when the current lookup index signal LUT_index to which the level of the current average power value P _avg belongs is outputted and the previous lookup table is changed, so that the level of the current average power value P _avg of the input signal is within a predetermined allowable range. Since the lookup table does not change even if the frequency changes frequently, the spectrums of the I and Q signal lookup output signals extracted from the lookup table fluctuate (Fl). The uctuation value does not occur and thus has an effect of stably compensating for the input signal to have a linear characteristic.

Description

Apparatus and method for retrieving average power level in a system using multiple lookup tables {AVERAGE POWER LEVEL SEARCH APPARATUS AND METHOD IN SYSTEM USING MULTI LOOK UP TABLE}

The present invention relates to a mobile communication system, and in particular, when detecting a level of a current average power value P _avg of an input signal using a multi-lookup table, an average power variation value according to the current average power value P _avg is predetermined. If the average power fluctuation value falls within a predetermined allowable range, the pre-stored previous lookup index signal (LUT) is output to maintain the previous lookup table, and the average power fluctuation value is determined. System using a multi-look up table that changes the previous lookup table by outputting the current lookup index signal (LUT_index) to which the level of the current average power value P _avg belongs only if it is out of a predetermined allowable range. An apparatus and method for searching average power level in.

FIG. 1 is a block diagram illustrating a configuration of an apparatus for detecting a power level of an input signal using a conventional multi-look up table. As shown therein, a power calculator 10 and a power size calculator 20 are illustrated in FIG. And the lookup index signal generator 30, the I signal and the Q signal lookup output signal generators 40 and 50, and the operation of the conventional apparatus configured as described above will be described.

In general, I and Q signals input from a mobile communication system have non-linear characteristics, and power levels of input signals using a multi-look up table to compensate each signal to have a linear characteristic. The detection device is used to improve and control the performance of the system.

When the signal is input, the power calculator 10 in the power level detecting apparatus of the input signal squares each input I signal and Q signal, and then adds the squared value to the input power (X = I ² + Q ² ). To calculate and output the power, the power size calculator 20 calculates the magnitude (Magnitude) for the input power (X) by calculating the square root (Square Root) of the output input power (X), the calculated value is It is output as a lookup address signal LUT_address and is input to the I and Q signal lookup output signal generators 40 and 50.

The lookup index signal generator 30 calculates an average power value P _ave of the input signal I signal and the Q signal by performing a predetermined operation on the output power X, and then averages the power P. a lookup index signal LUT_index corresponding to the level of _ave ) is output to the I and Q signal lookup output signal generators 40 and 50.

Then, the I and Q signal lookup output signal generators 40 and 50 receive the lookup address signal LUT_address and the lookup index signal LUT_index and use one of 16 lookup tables as the lookup index signal LUT_index. After selecting the lookup table, the data of the lookup table corresponding to the power level of the input signal is extracted in the lookup table selected as the lookup address signal (LUT_address) and output as an I signal and a Q signal lookup output signal. The nonlinearity of the Q signal is compensated to have a linear characteristic.

Here, the lookup index signal generator 30 is composed of an average power calculator 31, an average power scaler 32, and an average power level searcher 33, as shown in FIG. A process of outputting the lookup index signal LUT_index in the following description will be described with reference to FIGS. 3 and 4 as follows.

First, the average power calculator 31 receives the input power X from the power calculator 10 and calculates an average power value P _{avg -out} for the input power X, and average power magnitude. The controller 32 amplifies the magnitude of the average power value P _{avg -out with respect} to the calculated input power X to a predetermined level according to the average power magnitude signal P _{avg_scale} , and finally the average power value of the input signal. (P _avg ) is generated and output to the average power level finder 33 (S40).

Then, the average power level of the browser 33 are the average power value (P _avg) based on the average power value (P _{avg_L1} ~P _{avg_L15)} search (S41) a range of a predetermined level, the level of the fall of the input signal, and According to the search result, the index data (0000-1111) corresponding to the level of the average power value P _avg of the input signal is output as the lookup index signal LUT_index (S42).

At this time, the average power scaler 32 receives an average power size signal Pavg_scale of a predetermined size from a digital signal processor (DSP) (not shown) or a main processor (not shown) of the system. The average power value P _avg -out of the input power X is multiplied by the average power magnitude signal Pavg_scale to generate an average power value P _avg of the input signal amplified to a predetermined level.

In addition, when the system administrator updates the digital signal processor (DSP, Digital Signal Processor) (not shown) or the group 15 based on the average power value set by the main processor (not shown) of the system (P _{avg_L1} ~P _{avg_L15)} the average power level browser 33 receives the updated data as the above group based on the average power value (P _{avg_L1} ~P _{avg_L15)} for storing the updated look-up table from a register (not shown) signal is set comparator (33-19 Update the data in the

That is, prior to operating the system, the system manager 16 is equally divided by 15 based average power value (P _{avg_L1} ~P _{avg_L15)} a predetermined average power level of the browser 33, relative to the average power values (P _avg) of the input signal non-uniform (non-uniform) defining each level in the range, and then the average power level of the browser 33, the system administrator-defined group at one based average power value set (P _{avg_L1} ~P _{avg_L15)} input in accordance with the The range to which the level of the average power value P _avg of the signal belongs is searched.

The lookup index signal LUT_index which selects which lookup table from among 16 lookup tables in the I and Q signal lookup output signal generators 40 and 50 is addressed according to the search result is output.

Meanwhile, the average power level searcher 33 in the lookup index signal generator 30 includes a plurality of multiplexers 33-1 to 33-17, flip-flops 33-18, and comparators as shown in FIG. is composed of (33-19), the mean power level of the browser 33 is any of the 16 based average power value is a predetermined level of the average power value (P _avg) of the input signal (P _{avg_L1} ~P _{avg_L15)} range of the level By searching whether it is within the range, a lookup index signal (LUT_index) for selecting a lookup table to be addressed from among 16 lookup tables in the I and Q signal lookup output signal generators 40 and 50 is output.

That is, the comparators (33-19), the mean power value (P _avg) of the input signal within the mean power regulator size average power value of the input signal from the (32) the average power level browser 33 receives the input (P _avg) the level of the search whether it belongs to a range of the 16 range is generated based on the level of the 15 group based average power value (P _{avg_L1} ~P _{avg_L15)} is set sequentially to each of the unit level, the control signal according to By outputting to the multiplexers 33-1 to _33-17 , the range of the level of the predetermined reference average power values P _{avg_L1 to} P _{avg_L15} to which the level of the average power value P _avg of the input signal belongs is _determined . Four-bit index data (0000-1111) are output as a lookup index signal (LUT_index).

Here, when the system is initialized, the lookup index signal LUT_index becomes a signal of '0000', which is index data selected by the first multiplexer 33-1, and each of the multiplexers 33-1 to 33-16 is a system. In order to improve the performance and speed of the search, the search is started first by giving priority to the higher level range.

For example, is less than the level of the average power value (P _avg) of the input signal is greater than the reference average power value (P _{avg_L14)} or greater based on the average power value (P _{avg_L15),} a comparator (33-19) is the 15 The control signal is activated so that only the fifteenth multiplexer 33-15 selectively outputs predetermined index data '1110'.

The comparator 33-19 deactivates the control signals of the sixteenth multiplexer 33-16 and the other multiplexers 33-1 to 33-14, so that the sixteenth multiplexer 33-16 and the other multiplexer ( 33-1 to 33-14 prevent the preset digital signals 1111 and 0000 to 1101 from being output, and select and output only the signals input to the other input side.

In this manner, the average power value of the input signal from the mean power level of the browser (33) (P _avg) is the average of the power values (P _avg) by the 15 group based average power value (P _{avg_L1} ~P _{avg_L15)} set 16 index data (0000-1111) corresponding to a level can be converted, and one of the converted 16 index data (0000-1111) is the final multiplexer (33-17) and flip-flop (33-18). The signal is synchronized with the clock signal through the output signal as a lookup index signal (LUT_index).

By the way, in the prior art, the levels of the I and Q signals, which are input signals in the mobile communication system, do not remain constant but fluctuate around the corresponding levels, and the level of the average power value P _avg of the input signal is increased. a predetermined reference average power value when mails, at a boundary (P _{avg_L1} ~P _{avg_L15),} based on the average power value belonging to this level at the average power level of the browser 33, the average power value (P _avg) of said input signal (P _{avg_L1} the index look-up signal (LUT_index) output according to the range of the level of ~P _{avg_L15)} is also changed according to the level variation of the average power value (P _avg) of the input signal.

That is, _{assuming that} the level of the reference average power value P _{avg_L1} is set to '100' and the level of the reference average power value P _{avg_L2} is set to '200', the average power value of the input signal P _avg is determined. When the level changes as '101, 99, 102, 98, 101, ...' by a very small amount up and down about '100', lookup according to the level of the reference average power values P _{avg_L1} and P _{avg_L2} The index signal LUT_index is also changed so that the lookup tables in the I and Q signal lookup output signal generators 40 and 50 are changed as 'LUT1, LUT0, LUT1, LUT0, LUT1, ...', and thus the I signal. And I and Q signal lookup output signals which are outputs of the Q signal lookup output signal generators 40 and 50 are also changed.

As described above, the frequent change of the lookup table induces a phenomenon in which the I and Q signal lookup output signals are broken, resulting in fluctuation of the spectrum of the I and Q signal lookup output signals, which is an average power level searcher. (33) is composed of multiplexers (33-1 to 33-16) with priority and comparators (33-19) to continuously output the lookup index signal (LUT_index) according to the average power value (P _avg ) of the input signal. Because it is supposed to.

That is, in the prior art, the average power value of the input signal (P _avg) when changing frequently at the level of the group boundary based average power value (P _{avg_L1} ~P _{avg_L15)} is set, at an average power level browser 33 accordingly Continuously outputting the lookup index signal (LUT_index), the I signal and Q signal lookup output signal generators 40 and 50 extract the corresponding data from the previously addressed lookup tables and output a stable I signal and Q signal lookup output. A process of extracting data of a new lookup table before outputting as a signal is generated, so that the I and Q signal lookup output signal generators 40 and 50 generate a plurality of I and Q signal lookup output signals extracted from the lookup table. Fluctuation of the spectrum (Fluctuation) has a problem that occurs.

Accordingly, the invention is proposed that, the current average power value (P _avg) when detecting the level of the current average power value (P _avg) of the input signal using multiple look-up tables in order to solve the conventional problems as described above It is determined whether the average power fluctuation value within the predetermined allowable range, and if the average power fluctuation value falls within the predetermined allowable range, outputs a previously stored lookup index signal (LUT) to maintain the previous lookup table. And outputs a current lookup index signal (LUT_index) to which the level of the current average power value P _avg belongs only when the average power fluctuation value is out of a predetermined allowable range, thereby changing a previous lookup table. Has its purpose.

The present invention for achieving the above object, when detecting the level of the current average power value P _avg of the input signal using the multi-lookup table, the current average power value (P) for the input I signal and Q signal (P _an average power input reading _avg ); An average power fluctuation detector for determining an average power fluctuation value with respect to the current average power value P _avg using the current average power value P _avg and an input previous average power value P _level ; A change allowance range determiner for determining whether the average power change value is within a predetermined allowable range and outputting a change allowance range determination signal; According to the variable allowable range determination signal, the previously stored previous lookup index signal LUT is output as the current lookup index signal LUT_index or the current lookup index signal LUT_index to which the level of the current average power value P _avg belongs. ), And output the current lookup index signal (LUT_index) as the previous lookup index signal (LUT) and change its current average power value (P _avg ) to a previous average power value (P _level ). And a current lookup index signal outputted to the variation detector and a previous average power value generator.

In addition, the present invention, when detecting the level of the current average power value (P _avg ) of the input signal using the multi-lookup table, whether the average power fluctuation value according to the current average power value (P _avg ) falls within a predetermined allowable range Determining whether the average power change value is within a predetermined allowable range and outputting the previously stored previous lookup index signal LUT as a current lookup index signal LUT_index as it is; As a result of the determination, when the average power fluctuation value is out of a predetermined allowable range, retrieving index data to which the level of the current average power value P _avg belongs, and outputting the changed current lookup index signal LUT_index accordingly. Characterized in that.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a block diagram showing the configuration of an average power level search apparatus in a system using a multi-look up table according to the present invention. As shown therein, the average power input device 100 and the average power fluctuation detector are shown in FIG. 200, a current lookup index signal, a previous average power value generator 300, and a variable allowable range determiner 400.

In general, I and Q signals input from a mobile communication system have nonlinear characteristics. The present invention uses a multi-look up table to compensate for the linearity of each signal. It can be used in a system for detecting the level of the average power value of a signal.

In addition, the mobile communication system calculates the power of the input I signal and the Q signal, and calculates a current average power value P _ave for the input signal by performing a process of raising a predetermined operation and level to the calculated power. In the present invention, the average power input unit 100 reads the current average power value P _ave to the rising edge of the clock signal clk and transmits the average power change detector 200 to the rising power variation detector 200 (S70).

Then, the average power fluctuation detector 200 has a current average power value P _avg input from the average power input device 100, a previous average power value input from a current lookup index signal, and a previous average power value generator 300. The average power fluctuation value is determined using (P _level ) and output to the fluctuation allowance range determiner 400 (S71).

Here, the average power fluctuation detector 200 calculates the difference between the current average power value P _avg and the previous average power value P _level and determines and outputs the average power fluctuation value. Since the value P _level is '0', the average power fluctuation value becomes the current average power value P _avg , and then the previous average power value P _level changes according to the change of the current average power value P _avg . The average power fluctuation corresponding to the difference also changes.

On the other hand, the variable allowable range determiner 400 determines whether the average power fluctuation value is within a predetermined allowable range and outputs a variable allowable range determination signal (S72), where the system administrator is fine at the boundary of the lookup table. The upper limit value storage unit 410 and the lower limit value storage unit 420 in the variable allowable range determiner 400 are set by setting a negligible upper limit value and a lower limit value among changing current average power values P _avg . It is possible to save and change on.

The first comparator 430 reads the upper limit value from the upper limit value storing unit 410 and compares the upper limit value with the average power fluctuation value of the average power fluctuation detector 200, and the second comparator 430 compares the lower limit value. The lower limit value is read from the storage unit 420 and compared with the average power change value of the average power change detector 200 to determine whether the average power change value is within an allowable range of the upper limit value and the lower limit value. Output to AND gate 450.

That is, when the average power fluctuation value is within the allowable range of the upper limit value and the lower limit value, the first and second comparators 430 and 440 respectively output the 'activated state' signal to the AND gate 450, and thus, the AND gate. In operation 450, the variable tolerance range determination signal is output as an 'activated state'.

When the average power fluctuation value is greater than the upper limit value or less than the lower limit value, at least one of the first comparator 430 or the second comparator 440 sends an 'inactive state' signal to the AND gate 450. As a result, the AND gate 450 outputs the variable allowable range determination signal as a 'deactivated state'.

That is, the variable allowable range determiner 400 is in an 'active state' when the average power fluctuation value corresponding to the difference between the current average power value P _avg and the previous average power value P _level is within a predetermined allowable range. If it is out of the predetermined allowable range, the variable allowable range determination signal of the "deactivation state" is output to the current lookup index signal and the previous average power value generator 300.

Next, when the current allowable lookup index signal and the previous average power value generator 300 receive the variable allowable range determination signal of the 'active state', the pre-stored lookup index signal LUT is stored and the current lookup index signal LUT_index. (S76), and the output current lookup index signal LUT_index is any one of 16 lookup tables in a device such as the I and Q signal lookup output signal generators 40 and 50 in FIG. It is used to determine whether to address.

And, when the variation allowable range determination signal of "inactive" input, the current average power by searching the range of the level of the current value of the average power (P _avg) based on the average power value (P _{avg_L1} ~P _{avg_L15)} belonging to the level of ( to output the current look-up index signal (LUT_index) belonging to the level of the _{P avg) (S73, S74)} , in this case, since a variation level of the current average power value (P _avg), the current average power value of the input signal (P _avg) Is changed to the previous average power value (P _level ) and then fed back to the average power variation detector 200 and outputted, and the current lookup index signal (LUT_index) for selecting the current lookup table is returned to the previous lookup index. The previous lookup index signal LUT is used to detect the level of the current average power value P _avg for the next input signal by changing to the signal LUT and storing the same (S75).

Here, the operation of the current lookup index signal and the previous average power value generator 300 will be described. The current lookup index signal and the previous average power value generator 300 may include a plurality of multiplexers 301 to 317 and flip-flops. -flop) 318, comparator 319, and first and second tri-state buffers 320 and 321.

In addition, the present invention assumes that the lookup table has 16 indexes in consideration of the performance of the system, and accordingly sets the level of the current average power value P _avg to 15 preset reference average power values P _{avg_L1.} Assume that the lookup table is selected by dividing into 16 ranges generated based on the level of ˜P _{avg_L15} and using any one of 4-bit index data 0000 to 1111 as the current lookup index signal LUT_index. This may change the current lookup index signal and the previous average power value generator 300 as the number of lookup tables increases or decreases.

When the system calculates a current average power value P _ave for the input signal by performing a predetermined operation and a level to increase the calculated power of the input I and Q signals, the comparator 319 calculates the input signal. receives the average power value (P _avg), any of the 16 range is generated based on the level of the current average power value (P _avg) based on the average power value (P _{avg_L1} ~P _{avg_L15)} level is 15 in a predetermined By searching whether it is within a range and outputting a control signal according to the multiplexers 301 to 317, the 4-bit index data (0000 to 1111) preset according to the search result is converted into the current lookup index signal (LUT_index). To be printed.

In the present invention, when the system is initialized, the first multiplexer 301 outputs a signal of '0000' as index data. Accordingly, the current lookup index signal LUT_index becomes index data of '0000', and the previous average power. The value (P _level ) becomes '0'.

In addition, each of the multiplexers 301 to 316 has a priority. In general, the multiplexers 301 to 316 give priority to a high level range for improving system performance and search speed, and thus the level of the current average power value P _avg is a reference average. The search is first started as to whether the power value P _{avg_L15} is exceeded.

If, is less than equal to the reference average power value (P _{avg_L14)} level of the current average power value (P _avg) of the input signal to or greater based on the average power value (P _{avg_L15),} comparator 319 is a fifteenth control signal By activation, only the fifteenth multiplexer 315 selectively outputs predetermined index data '1110'.

The comparator 319 deactivates the control signals of the sixteenth multiplexer 316 and the other multiplexers 301 to 314 so that the sixteenth multiplexer 316 and the other multiplexers 301 to 314 are preset index data ( 1111 and 0000 to 1101 are not outputted and only the signal input to the other input side is selected and output.

In this manner, the current value of the average power (P _avg) of the input signal from the current look-up index signal and the previous average power value generator 300 is a 16 by 15 group based average power value set (P _{avg_L1} ~P _{avg_L15)} Index data (0000 to 1111), and then one of the 16 converted index data (0000 to 1111) is synchronized to a clock signal through the final seventeenth multiplexer (317) and flip-flop (318). It is output as a lookup index signal (LUT_index).

Here, the seventeenth multiplexer 317 is controlled by the variable tolerance range determination signal of the 'activated state' or 'deactivated state' of the variable tolerance range determiner 400, where the current average power value P _avg is a previous average. The variation allowable range determination signal of the 'activated state' outputted when it is changed within a predetermined allowable range relative to the power value P _level deactivates the first and second tri-state buffers 320 and 321 and the seventeenth multiplexer ( 317).

Then, the current lookup index signal and the previous average power value generator 300 do not search the index data (0000-1111) to which the level of the current average power value P _avg belongs and output the current lookup index signal LUT_index. By continuously outputting the previously stored previous lookup index signal (LUT) through the flip-flop 318, the previous average power value (P _level ) output to the average power fluctuation detector 200 is maintained to maintain the current average power. When the value P _avg changes within a predetermined allowable range, the lookup table is not changed.

On the other hand, when the current average power value P _avg fluctuates out of a predetermined allowable range compared to the previous average power value P _level , the output of the allowable range determination signal for the 'deactivated state' is output. The three-state buffers 320 and 321 are activated and the seventeenth multiplexer 317 is controlled.

Then, the current lookup index signal and the previous average power value generator 300 retrieve the index data (0000-1111) to which the level of the current average power value P _avg belongs and output the current lookup index signal (LUT_index). When the average power value P _avg changes out of a predetermined allowable range, the lookup table is changed.

In addition, the current lookup index signal and the previous average power value generator 300 change the input current average power value P _avg to a previous average power value P _level and output the average power fluctuation detector 200. The 17th multiplexer 317 stores the current lookup index signal LUT_index as the previous lookup index signal LUT to detect the level of the current average power value P _avg for the next input signal. Use the stored previous lookup index signal (LUT).

Here, when the system administrator has to update the digital signal processor (DSP, Digital Signal Processor) (not shown) or the group 15 based on the average power value set by the main processor (not shown) of the system (P _{avg_L1} ~P _{avg_L15)} , the current look-up index signal and the previous average power value generator 300 that the updated data based on the predetermined average power value (P _{avg_L1} ~P _{avg_L15)} a register (not shown), a look-up table update signal (L1~ from the store L15) to update the data in the comparator 319.

As described above, in the present invention, when detecting the level of the current average power value P _avg of the input signal using the multiple lookup table, the average power fluctuation value according to the current average power value P _avg is allowed. If the average power fluctuation value falls within a predetermined allowable range, the pre-stored previous lookup index signal (LUT) is output to maintain the previous lookup table, and the average power fluctuation value is determined. Only when it is out of the allowable range, the current lookup index signal LUT_index to which the level of the current average power value P _avg belongs is outputted and the previous lookup table is changed to change the level of the current average power value P _avg of the input signal. Since the lookup table does not change even if it changes frequently within a predetermined allowable range, the I and Q signal lookup output signals extracted from the lookup table are changed. This phenomenon does not occur spectrum is turbulent (Fluctuation) it is effective to stably compensate the input signal to have linear characteristics.

1 is a block diagram showing a configuration of an apparatus for detecting a power level of an input signal using a conventional multi-look up table.

2 is a block diagram showing a configuration of a lookup index signal generator in a power level detection apparatus of an input signal using a conventional multiple lookup table.

3 is a block diagram showing a configuration of an average power level searcher in a power level detection apparatus of an input signal using a conventional multiple lookup table.

4 is a flowchart illustrating an operation process of a power level detection method of an input signal using a conventional multiple lookup table.

5 is a block diagram showing the configuration of an average power level search apparatus in a system using the multi-lookup table of the present invention.

Figure 6 is a block diagram showing the configuration of the current lookup index signal and the previous average power value generator in the average power level search apparatus in the system using the multi-lookup table of the present invention.

Figure 7 is a flow chart showing the operation of the average power level search method in a system using the multi-lookup table of the present invention.

*** Description of the symbols for the main parts of the drawings ***

100: average power input unit 200: average power fluctuation detector

300: current lookup index signal and previous average power value generator

301 to 317: multiplexer 318: flip-flop

319: comparator 320,321: first and third tri-state buffer

400: allowable variable range determiner 410: upper limit storage unit

420: lower limit storage unit 430, 440: first and second comparators

450: endgate

Claims (6)

An average power input for reading a current average power value P _avg for the input I signal and the Q signal when detecting the level of the current average power value P _avg of the input signal using the multiple lookup table; An average power fluctuation detector for determining an average power fluctuation value with respect to the current average power value P _avg using the current average power value P _avg and an input previous average power value P _level ; A change allowance range determiner for determining whether the average power change value is within a predetermined allowable range and outputting a change allowance range determination signal; According to the variable allowable range determination signal, the previously stored previous lookup index signal LUT is output as the current lookup index signal LUT_index or the current lookup index signal LUT_index to which the level of the current average power value P _avg belongs. ), And output the current lookup index signal (LUT_index) as the previous lookup index signal (LUT) and change its current average power value (P _avg ) to a previous average power value (P _level ). An apparatus for searching average power level in a system using a multiple lookup table, comprising a current lookup index signal outputted to a variation detector and a previous average power value generator. The system of claim 1, wherein the average power change detector determines the average power change by a difference between a current average power value P _avg and a previous average power value P _level . Average power level search device in. When detecting the level of the current average power value P _avg of the input signal using the multi-lookup table, it is determined whether the average power fluctuation value according to the current average power value P _avg falls within a predetermined allowable range. Outputting the pre-stored previous lookup index signal (LUT) as a current lookup index signal (LUT_index) if the average power variation value is within a predetermined allowable range; As a result of the determination, when the average power fluctuation value is out of a predetermined allowable range, retrieving index data to which the level of the current average power value P _avg belongs, and outputting the changed current lookup index signal LUT_index accordingly. Mean power level search method in a system using a multi-lookup table, characterized in that. 4. The average power level of the system using the multiple lookup table according to claim 3, wherein the average power change value is determined by a difference between a current average power value P _avg and a previous average power value P _level . Search method. The method of claim 3, wherein the outputting of the previous lookup index signal LUT as the current lookup index signal LUT_index as it is is performed, determining the allowable variation range of the 'active state' when the average power fluctuation value is within a predetermined allowable range. Outputting a signal; The method may further include selecting a pre-stored previous lookup index signal (LUT) by the variable allowable range determination signal having the 'active state' and outputting the current lookup index signal as a current lookup index signal (LUT_index). How to find average power level in the system. The method of claim 3, wherein the outputting of the changed current lookup index signal (LUT_index) comprises: outputting a change tolerance range determination signal of a 'deactivated state' when the average power change value is out of a predetermined allowable range; The previous lookup index signal (LUT) is changed to the current lookup index signal (LUT_index) and stored, and the previous average power value (Plevel) is changed to the current average power value (Pavg) by the variable allowable range determination signal of the 'deactivation state'. The method of claim 1, further comprising the step of outputting the modified output.