KR20070004169A - Apparatus for estimating carrier to interference noise ratio in mobile communication system - Google Patents

Abstract

An apparatus for estimating a carrier to interference noise ratio(CINR) in a mobile communication system is provided to estimate the CINR accurately, by estimating noise power of a signal by using similarity of the channel characteristics of each adjacent sub carrier in sub carriers of a receiving signal. In an apparatus for estimating a carrier to interference noise ratio(CINR) in a mobile communication system, a first calculation part generates an ith calculation value T(i) by calculating a difference between a (i+1)th pilot sub carrier and an ith pilot sub carrier. A memory stores the ith calculation value T(i) and a (i-1)th calculation value T(i-1). A second calculation part(606) selects one of the ith calculation value T(i) and zero according to the value i, and selects one of the (i-1)th calculation value T(i-1) and zero, and outputs a different of two selected values to a third calculation part(609). The third calculation part squares the output value from the second calculation part, and multiplies the squared output value by 1/2 or 1/6 according to the value i, and outputs the multiplied value to a fourth calculation part. The fourth calculation part estimates noise by adding result values outputted from the third calculation part.

Description

Signal-to-Interference and Noise Ratio Estimation System in Mobile Communication System {APPARATUS FOR ESTIMATING CARRIER TO INTERFERENCE NOISE RATIO IN MOBILE COMMUNICATION SYSTEM}

1 is a diagram illustrating a configuration of an OFDM receiver including a CINR estimator according to the present invention;

2 is a diagram illustrating a configuration of a CINR estimator including an interference and noise power estimating apparatus according to the present invention;

3 is a view illustrating an interference and noise power estimation apparatus according to the present invention;

4 is a block diagram implemented by serially processing an interference and noise estimation apparatus according to the present invention;

5 is a block diagram of an interference and noise estimation apparatus according to a first embodiment of the present invention; and

6 is a block diagram implementing the interference and noise estimation apparatus according to a second embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to an apparatus for estimating signal to interference and noise ratio.

Orthogonal Frequency Division Multiplexing (OFDM), which is recently used as a useful method for high-speed data transmission in a wired / wireless channel, is a method of transmitting data using a plurality of carriers. A method of converting data in parallel and modulating the data into a plurality of sub-carriers (or sub-channels) having mutual orthogonality to each other is transmitted.

The orthogonal frequency division multiplexing (OFDM) scheme is similar to the conventional frequency division multiplexing (FDM) scheme, but transmits data while maintaining orthogonality between a plurality of subcarriers, thereby providing optimum data transmission at high speed. The transmission efficiency can be obtained, the frequency efficiency is good, and the characteristics are strong against multi-path fading. In addition, by using the frequency spectrum superimposed, it is strong in frequency selective fading, and the inter-symbol interference effect can be reduced by using a guard period. In addition, it is possible to simply design the equalizer structure in hardware and has the advantage of being resistant to impulsive noise.

In addition, the orthogonal frequency division multiplexing (OFDM) method is a hardware complexity due to the development of various digital signal processing technologies including the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT). Digital transmission such as digital / audio broadcasting, digital TV, wireless local area network (WLAN), wireless asynchronous transfer mode (WATM), and broadband wireless access (BWA) It is widely applied to the technology.

On the other hand, a wireless communication system based on the Orthogonal Frequency Division Multiplexing (hereinafter, referred to as OFDM) or Orthogonal Frequency Division Multiple Access (hereinafter, referred to as OFDMA) (hereinafter referred to as OFDM) In this case, channel signal quality, for example, carrier to interference noise ratio (CINR), which is a parameter required for power control or adaptive modulation and demodulation, needs to be measured. Here, the adaptive power control or the adaptive modulation and demodulation device controls the power and adjusts the demodulation level according to the channel quality using the CINR value. The CINR is defined as a value obtained by dividing the total signal power of each subcarrier by the sum of noise and interference power, and is a measure of transmission / reception channel quality determination in an OFDM system.

Conventional carrier to interference and noise ratio (CINR) estimation technique estimates the noise level using a guard band, thereby estimating the CINR. However, the number of subcarriers used for estimating the noise level is not sufficient, and thus, the accuracy of the CINR may be degraded, and the noise level may be estimated to be higher than actual due to the ACLR (Adjacent Channel Leakage Ratio). Accordingly, there is a need for an apparatus for more accurately estimating the CINR in the OFDM system.

Accordingly, an object of the present invention is to provide an apparatus for estimating signal to interference and noise ratio in a mobile communication system.

It is still another object of the present invention to estimate the noise power of a signal using similar characteristics of a channel experienced by each adjacent subcarrier in subcarriers of a received signal in a mobile communication system, thereby providing a more accurate signal to interference and noise ratio ( CINR) estimation apparatus.

Another object of the present invention is to provide an interference and noise estimation apparatus using an optimized DASS algorithm in a mobile communication system.

According to a first embodiment of the present invention, an apparatus for estimating signal-to-interference and noise ratio in a mobile communication system includes calculating an i-th by calculating a difference between an i + 1 th pilot subcarrier and an i th pilot subcarrier A first operation unit for generating an operation value T (i), a memory for storing the i-th operation value T (i) and an i-1th operation value T (i-1), and an i-th according to the i value Selecting one of operation values T (i) and 0, selecting one of the i-1 th operation values T (i-1) and 0, and calculating and outputting a difference between the selected two values to a third operation unit. A second operation unit, a third operation unit squared with an output value from the second operation unit, and multiplied by 1/2 or 1/6 according to the i value and output to the fourth operation unit; and a result value output from the third operation unit And a fourth calculating unit for estimating noise by adding them.

According to a second embodiment of the present invention, an apparatus for estimating signal-to-interference and noise ratio in a mobile communication system includes calculating a difference between an i th pilot subcarrier and an i + 1 th pilot subcarrier, A first calculating unit for outputting to the calculating unit, a second calculating unit for calculating the difference between the i-th pilot subcarrier and the i-th pilot subcarrier, and outputting the difference to the third calculating unit; and output P (i) according to the i value Select one of 0) -P (i + 1) and 0, select one of outputs P (i) -P (i-1) and 0 of the second calculator, and calculate the sum of the selected two values A third operation unit outputting to a fourth operation unit, a fourth operation unit which squares an output value from the third operation unit, multiplies 1/2 or 1/6 according to the i value, and outputs the result to the fifth operation unit; 4 estimates noise by adding result values And a fifth calculating part.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, an interference and noise estimating apparatus for estimating a noise power of a signal by using similar characteristics of a channel experienced by each adjacent subcarrier in subcarriers of a received signal in a mobile communication system will be described.

1 is a diagram illustrating a configuration of an OFDM receiver including a CINR estimator according to the present invention.

Referring to FIG. 1, an OFDM receiver includes an antenna 101, an RF processor 103, a guard interval remover 105, a serial / parallel converter 107, an FFT 109, an equalizer 111, and a channel estimator ( 113 and CINR estimator 115.

The RF processor 103 outputs the channel data from the wireless channel received through the antenna 101 to the guard interval remover 105. The guard interval remover 105 removes the guard interval from the received channel data. The serial / parallel converter 107 converts the serial data and the redundant data from which the guard interval has been removed into a plurality of parallel data and outputs the data to the fast Fourier transformer (FFT) 109. The fast Fourier transformer 109 performs Fourier transform on the parallel data and the surplus data at high speed, and outputs the Fourier transformed data to the equalizer 111.

The equalizer 111 removes signal distortion due to Fourier transformed information data and excess data channels, and outputs data from which signal distortion has been removed. The channel estimator 113 estimates the channel state according to the distortion of the phase and amplitude in the frequency domain due to the channel degradation occurring during transmission and reception, and compensates for the distortion of the phase amplitude in the frequency domain. The CINR estimator 115 then measures the channel quality, i. E. CINR.

As described above, a transmitter of an OFDM system transmits a modulated signal by performing a fast Fourier Inverse Transform (IFFT) and then attaches a guard interval. In contrast, the receiver first removes the guard interval and then performs a Fast Fourier Transform (FFT). Demodulate to obtain the transmitted signal. In this case, when a transmitter of the OFDM system transmits a digital signal of a known pattern such as a pilot signal or a preamble signal, the OFDM receiver receiving the estimated signal estimates the CINR using the received signal.

2 is a diagram illustrating a configuration of a CINR estimator including an interference and noise power estimating apparatus according to the present invention.

Referring to FIG. 2, a carrier to interference and noise ratio (CINR) estimator 115 includes a signal power estimator 201 for estimating total received signal power, interference and noise power of a received preamble or pilot signal. And an interference and noise power estimator 203 for estimating a noise level, a noise level estimator 205 for estimating a noise level of a received signal, and a CINR calculator 207 for estimating a CINR in a data interval. Here, the CINR estimator 115 outputs the signal output from the FFT 109 to the signal power estimator 201, the interference and noise power estimator 203, and the noise level estimator 205.

The signal power estimator 201 estimates the power of the received signal. In detail, the signal power estimator 201 obtains the power of each subcarrier of the signal received from the FFT unit 109, and then adds the power of each subcarrier to estimate the power of the signal and uses the estimated signal power information as a CINR calculator ( 207).

The interference and noise power estimator 203 estimates the noise power of the received signal and outputs the estimated noise power information to the CINR calculator 207. The interference and noise power estimator 203 according to an embodiment of the present invention estimates the noise power of a signal by using similar characteristics of a channel experienced by each adjacent subcarrier in the subcarriers of the received signal.

The noise level estimator 205 estimates the noise level of the received signal and provides the estimated noise level information to the CINR calculator 207. Here, the noise level estimator 205 may estimate the noise level using signal powers of a plurality of subcarriers on which no signal is carried.

The CINR calculator 207 receives power information of the entire received signal from the signal power estimator 201 and noise power information of the received signal from the interference and noise power estimator 203. The CINR calculator 207 also receives noise level information from the noise level estimator 205. In this case, the CINR calculator 207 estimates the CINR in the data interval by using the provided information.

Here, the CINR is defined as a value obtained by dividing the sum of signal power of each subcarrier by the sum of noise and interference power, and is generally defined as Equation 1 below.

Here, P (i) denotes the i-th pilot subcarrier, I (i) denotes the interference and noise power corresponding to the i-th pilot, and i denotes the index of the pilot subcarrier.

The sum of noise and interference power for calculating the CINR, that is, I (i), is generally calculated through a DIF (Difference of Adjacent Subcarrier Signal) method. In this case, the calculation for the interference and noise power estimation is performed using Equation 2.

FIG. 3 is a diagram illustrating the hardware implementation of the interference and noise power estimator of the CINR estimator using the DASS technique. Here, the interference and noise power estimator 203 includes M-2 multipliers 301-2 to 301-M-1, M adders 302-1 to 302-M, and M calculators 303. -1 to 303-M) and a summer 304.

Referring to FIG. 3, the first adder 302-1 calculates and outputs a difference between the first pilot subcarrier P (1) and the second pilot subcarrier P (2), and the Mth adder 302 -M. Calculates and outputs the difference between the Mth pilot subcarrier P (M) and the M-1st pilot subcarrier P (M-1). The second adder 302-2 to the M-1 adder 302-M-1 multiply the corresponding i-th pilot subcarrier P (i) by 2, and then double the P (i). Outputs a value obtained by subtracting the i-1 th pilot subcarrier P (i-1) and the i + 1 th pilot subcarrier P (i + 1). Here, M denotes the number of adjacent pilot subcarriers having similar channel characteristics in the frequency domain.

Thereafter, the first calculator 303-1 and the M-th calculator 303 -M square the result values output from the corresponding first adder 302-1 and the M-th adder 302 -M, respectively. , Dividing by 2 and printing The second calculator 303-2 to the M-1 calculator 303-M-1 respectively square the result of the corresponding adder, divide the result by 6, and output the result to the summer 304. The summer 304 adds all the values output from the M calculators 303-1 to 303-M to obtain the total interference and noise signal power.

Here, when there are a lot of parallel processing as shown in FIG. 3, since there are various side effects such as the size of the circuit is increased and thus the power consumption is increased, there is an actual implementation.

Referring to FIG. 4, the first delay unit 401 delays and outputs the input pilot subcarriers by one time. The second delay unit 402 delays and outputs the pilot subcarriers from the first delay unit by a predetermined time, and the third delay unit 403 delays and outputs the pilot subcarriers from the second delay unit by a predetermined time. Herein, the output from the first delay unit is assumed to be an i + 1th pilot subcarrier, the output from the second delay unit is assumed to be an i-th pilot subcarrier, and the output from the third delay unit is i-1. Assume the first pilot subcarrier.

Thereafter, the first adder 404 subtracts the output P (i + 1) of the first delay unit 401 from the output P (i) of the second delay unit 402 and then uses the fourth delay unit ( 409, and the second adder 405 calculates a difference between the pilot subcarriers output from the second delay unit 402 and the third delay unit 403 and outputs the difference to the sixth delay unit 411. . The shifter 406 shifts the value from the second delay unit 402, that is, doubles the calculation and outputs the result to the third adder 407. At this time, the third adder 407 subtracts the output P (i + 1) of the first delay unit 401 from the output 2P (i) of the shifter 406 and then adds the result value to the fourth adder. 408, and the fourth adder 408 outputs P (of the third delay unit 403 from an output 2P (i) -P (i + 1) of the third adder 407. i-1) is subtracted and then output to the fifth delay unit 410.

The selecting unit 412 outputs the outputs of the fourth delay unit 409, the fifth delay unit 410, and the sixth delay unit 411 according to the i value representing the index of the subcarrier, that is, P (i). Select one of -P (i + 1) and 2P (i) -P (i-1) -P (i + 1) and P (i) -P (i-1) to the first calculator 413. Output Here, as shown in Equation 2, if i is 1, the output P (i) -P (i + 1) of the fourth delay unit 409 is output to the first calculation unit 413, and If i is M, the outputs P (i) -P (i-1) of the sixth delay unit 411 are output to the first calculation unit 413. If i is not 1 or M, the outputs 2P (i) -P (i-1) -P (i + 1) of the fifth delay unit 410 are output to the first calculator 413. Here, the selector 412 may use a 3x1 multiplexer.

Thereafter, the first calculator 413 squares the value output from the selector 412, multiplies 1/2 or 1/6 according to the i value, and outputs the result to the summer 304. Here, if i is 1 or M, the value output from the selector 412 is multiplied by 1/2, and if i is not 1 or M, the value output from the selector 412 is 1 / m. Multiply by 6.

Here, the implementation of Equation 2 and FIGS. 3 and 4 is a simple implementation of an algorithm, and uses a method of separately calculating and selecting each case. In this case, by properly modifying Equation 2, the hardware implementation may be optimized.

In order to optimize the hardware implementation, Equation 2 may be modified as in Equation 3 below.

5 is a block diagram of an interference and noise estimation apparatus according to the first embodiment of the present invention using Equation 3 above.

 Referring to FIG. 5, the first delay unit 501 delays and outputs input pilot subcarriers by one time. The second delay unit 502 delays and outputs pilot subcarriers from the first delay unit for a predetermined time, and the third delay unit 503 outputs the pilot subcarriers from the second delay unit for a predetermined time. Herein, the output from the first delay unit is assumed to be an i + 1th pilot subcarrier, the output from the second delay unit is assumed to be an i-th pilot subcarrier, and the output from the third delay unit is i-1. Assume the first pilot subcarrier.

Thereafter, the first adder 504 subtracts the output P (i + 1) of the first delay unit 501 from the output P (i) of the second delay unit 502 and then uses the fourth delay unit ( 506, and the second adder 505 calculates a difference between the pilot subcarriers output from the second delay unit 502 and the third delay unit 503 and outputs the difference to the fifth delay unit 507. .

The first selector 508 selects one of the output P (i) -P (i + 1) and 0 of the fourth delay unit 506 according to the i value representing the index of the subcarrier and adds the third adder ( 510). Here, as shown in Equation 3, if i is M, 0 is output to the third adder 510. If i is not M, P (i) -P (i + 1) 3 is output to the adder 510. The second selector 509 selects one of the outputs P (i) -P (i-1) and 0 of the fifth delay unit 507 and 0 according to the i value representing the index of the subcarrier and adds the third adder ( 510). Here, as shown in Equation 3, if i is 1, 0 is output to the third adder 510, and if i is not 1, P (i) -P (i-1) is removed. 3 is output to the adder 510. Here, the first selector 508 and the second selector 509 may use a 2 × 1 multiplexer, and select and output one of the two input signals.

Thereafter, the third adder 510 adds the output values of the first selector 508 and the second selector 509 and outputs the output values to the first calculator 511. Here, as shown in Equation 3, if i is 1, the output P (i) -P (i + 1) of the first selector 508 and the output 0 of the second selector 509 are zero. Is added and output to the first calculation unit 511. If i is M, output 0 of the first selection unit 508 and output P (i) -P (i-) of the second selection unit 509. 1) is added and output to the first calculation unit 511. In addition, when i is any other value, the third adder 510 is configured to output the output P (i) -P (i + 1) of the first selector 508 and the second selector 509. The outputs P (i) -P (i-1) are added and output to the first calculation unit 511.

Thereafter, the first calculator 511 squares the value output from the third adder 510, multiplies 1/2 or 1/6 according to the i value, and outputs the result to the summer 304. do. Here, if i is 1 or M, the value output from the third adder 510 is multiplied by 1/2, and if i is not 1 or M, the value is output from the third adder 510. Multiply by 1/6. In this case, it can be seen that the hardware structure is much simpler than the case of FIG. 4 in which hardware is implemented using Equation 2.

If the Equation 3 is partially modified again, the Equation 3 is transformed into the same Equation 4.

Here, it may be confirmed that the following Equation 5 is repeated, and Equation 4 may be modified to the same as Equation 6 using Equation 5.

6 is a block diagram of an interference and noise estimation apparatus according to the second embodiment of the present invention using Equation 6.

Referring to FIG. 6, the first delay unit 601 delays the input pilot subcarriers by one time and outputs the result, and the second delay unit 602 outputs the pilot subcarriers from the first delay unit by a predetermined time. Delayed output. Herein, it is assumed that the output from the first delay unit is an i + 1th pilot subcarrier, and the output from the second delay unit is an i-th pilot subcarrier.

Thereafter, the first adder 603 subtracts the output P (i + 1) of the first delay unit 601 from the output P (i) of the second delay unit 602 and subtracts the result value T. After storing as (i), it outputs to the 3rd delay part 604.

The third delay unit 604 outputs the delayed output T (i) of the first adder 603 by one time, and the fourth delay unit 605 of the third delay unit 604 The output value is delayed for a predetermined time and output. Here, if the output from the third delay unit 604 is assumed to be T (i), the output from the second delay unit may be assumed to be T (i-1).

The first selector 606 selects one of the output T (i) and zero of the third delay unit 604 and outputs it to the second adder 608 according to an i value representing the index of the subcarrier. Here, as shown in Equation 6, if i is M, 0 is output to the second adder 608, and if i is not M, T (i) is transmitted to the second adder 608. Output The second selector 607 selects one of the output T (i-1) and 0 of the fourth delay unit 605 and outputs it to the second adder 608 according to the i value indicating the index of the subcarrier. . Here, as shown in Equation 6, if i is 1, 0 is output to the second adder 608, and if i is not 1, T (i-1) is added to the second adder 608. ) The first selector 606 and the second selector 607 may use a 2 × 1 multiplexer, and select and output one of the two input signals.

Thereafter, the second adder 608 subtracts the output values of the first selector 606 and the second selector 607 and outputs them to the first calculator 609. Here, as shown in Equation 6, if i is 1, the output T (i) of the first selector 606 and the output 0 of the second selector 607 are subtracted and the first calculator ( 609, and when i is M, the output 0 of the first selector 606 and the output T (i-1) of the second selector 607 are subtracted to the first calculator 609. Output Further, when i is any other value, the second adder 608 outputs T (i) of the first selector 606 and output T (i-1) of the second selector 607. Is subtracted and output to the first calculator 609.

Thereafter, the first calculator 609 squares the value output from the second adder 608 and multiplies 1/2 or 1/6 according to the value of i to output the result to the summer 304. do. Here, if i is 1 or M, the value output from the second adder 608 is multiplied by 1/2, and if i is not 1 or M, the value is output from the second adder 608. Multiply by 1/6. Here, FIG. 6 may share one adder in the entire calculation by storing the calculation for T (i).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention optimizes the implementation of the DASS algorithm for measuring interference and noise in a mobile communication system, which simplifies the overall hardware structure, improves the computational speed, and furthermore has a kind of pipeline structure to operate. There is an advantage that can contribute to improvement.

Claims (12)

An apparatus for estimating signal to interference and noise ratio in a mobile communication system, a first calculating unit calculating the difference between the i + 1th pilot subcarrier and the i th pilot subcarrier to generate an i th operation value T (i); A memory for storing the i th operation value T (i) and the i-1 th operation value T (i-1); Select one of the i th operation value T (i) and 0 according to the i value, select one of the i-1 th operation value T (i-1) and 0, and calculate a difference between the selected two values A second operation unit outputting to the third operation unit, A third operation unit which squares an output value from the second operation unit, multiplies 1/2 or 1/6 according to the i value, and outputs the result to the fourth operation unit; And a fourth calculator configured to estimate noise by adding result values output from the third calculator. The method of claim 1, The second operation unit selects 0 out of T (i) and 0 when T is i, and selects T (i-1) out of T (i-1) and 0 when i is 1, and when i is 1 Selects T (i) of the T (i) and 0, selects T (i-1) and 0 of 0, and when i is any other value, T (i) of T (i) and 0 And select T (i-1) among the T (i-1) and 0. The method of claim 1, The third calculator, when i is 1 or M, multiplies the output value of the second calculator by 1/2 and multiplies by 1/2, and when i has another value, squares the output value of the second calculator. And multiply by 1/6 to output the device. The method of claim 1, A signal power estimation device for estimating the total received signal power; A noise level estimating apparatus for estimating a noise level of a received signal; A signal-to-interference and noise ratio (CNR) for estimating a signal to interference and noise ratio (CINR) in a data interval by using the signal power estimator and outputs from the noise estimator and noise level estimator And a CINR) calculating device. The method of claim 4, wherein And the noise level estimating apparatus estimates the total noise level by using signal power of some subcarriers in which no signal is loaded among all received subcarriers. The method of claim 4, wherein The signal-to-interference and noise ratio (CINR) calculating device calculates the difference between the power of the entire signal output from the signal power estimating device and the interference and noise power output from the noise level power estimating device to obtain the pure signal power. Device. An apparatus for estimating signal to interference and noise ratio in a mobile communication system, a first calculating unit calculating a difference between the i th pilot subcarrier and the i + 1 th pilot subcarrier and outputting the difference to the third calculating unit; a second operation unit which calculates a difference between the i th pilot subcarrier and the i-1 th pilot subcarrier and outputs the difference to the third operation unit; One of the outputs P (i) -P (i + 1) and 0 of the first calculator is selected according to the value of i, and among the outputs P (i) -P (i-1) and 0 of the second calculator. A third calculator which selects one and calculates a sum of the selected two values and outputs the sum to the fourth calculator; A fourth operation unit which squares an output value from the third operation unit, multiplies 1/2 or 1/6 according to the i value, and outputs the result to the fifth operation unit; And a fifth calculator configured to estimate noise by adding result values output from the fourth calculator. The method of claim 7, wherein The third operation unit selects P (i) -P (i + 1) from among P (i) -P (i + 1) and 0 when i is 1, and selects P (i) -P (i -1) and 0 of 0 are selected, and when i is M, P (i) -P (i + 1) and 0 of 0 are selected and P (i) -P (i-1) and 0 are selected. P (i) -P (i-1) is selected, and if i has other values, P (i) -P (i + 1) and P (i) -P (i + 1) of 0 ) And P (i) -P (i-1) among P (i) -P (i-1) and 0. The method of claim 7, wherein The fourth calculating unit squares the output value of the third calculating unit when i is 1 or M, and then multiplies and outputs the multiplied by 1/2, and squares the output value of the third calculating unit when i has other values. And multiply by 1/6 to output the device. The method of claim 7, wherein A signal power estimation device for estimating the total received signal power; A noise level estimating apparatus for estimating a noise level of a received signal; A signal-to-interference and noise ratio (CNR) for estimating a signal to interference and noise ratio (CINR) in a data interval by using the signal power estimator and outputs from the noise estimator and noise level estimator And a CINR) calculating device. The method of claim 10, And the noise level estimating apparatus estimates the total noise level by using signal power of some subcarriers in which no signal is loaded among all received subcarriers. The method of claim 10, The signal-to-interference and noise ratio (CINR) calculating device calculates the difference between the power of the total signal output from the signal power estimating device and the interference and noise power output from the noise level power estimating device to obtain the pure signal power. Characterized in that the device.

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