KR101022417B1 - Carrier to interference and noise ratio estimator for wimax system - Google Patents

Abstract

Disclosed is a signal to interference and noise ratio estimation apparatus for a WiMAX system. The signal-to-interference and noise ratio estimation apparatus for the WiMAX system receives a pilot signal extractor for providing the first to fourth pilot signals included in a cluster from the frequency signal converted into the frequency domain, and receives the first to fourth pilot signals, Estimates power values of interference and noise signals included in the second pilot signal using the first to third pilot signals and powers of interference and noise signals included in the third pilot signal using the second to fourth pilot signals. A power estimator for estimating the interference and noise signal power values and the data signal power values through estimating the values, and the signal-to-interference and signal-to-interference and noise ratio calculations using the interference and noise signal power values and the data signal power values, and And a noise ratio calculator. Therefore, the signal-to-interference and noise ratio estimator for WiMAX systems provides a highly accurate CINR estimate.

Description

Signal-to-Interference and Noise Ratio Estimation System for WiMAX System {CARRIER TO INTERFERENCE AND NOISE RATIO ESTIMATOR FOR WIMAX SYSTEM}

The present invention relates to a signal to interference and noise ratio (CINR) estimation apparatus, and more particularly to a CINR estimation apparatus for a world wide interoperability for microwave access (WiMAX) system.

In general, when data is transmitted at high speed in a wireless channel, a high bit error rate is required due to the effects of multipath fading and Doppler spread, and thus a wireless access method suitable for a wireless channel is required. The OFDM scheme is suitable for high speed data transmission in a wireless channel.

OFDM is a type of multi-carrier transmission using multiple carriers.It converts a wideband signal serially input into N parallel data strings and divides them into several subcarriers having orthogonality to each other and transmits them in parallel so that each channel has the same number of carriers. The transmission period at will increase.

As a result, when the data is sequentially transmitted using a single carrier, the interval of transmitted symbols is longer, and thus the channel delay time is less affected. It has the effect of changing to the frequency non-selective channel characteristic. Therefore, the complexity of channel equalization can be reduced.

In addition, due to the orthogonality of subcarriers, each subcarrier is allowed to overlap in the spectrum, thereby increasing the efficiency of the spectrum compared to a general frequency division scheme, and the receiver can separate the subcarriers using simple signal processing techniques.

In such an OFDM scheme, it is important to accurately measure the channel signal quality for power control or modulation and demodulation. Channel signal quality is generally expressed as a carrier to interference and noise ratio (CINR), which is defined as the sum of the signal power of each subcarrier divided by the sum of the interference and noise power. By accurately estimating CINR, it is possible to improve the performance of adaptive modulation and coding (AMC).

In the world wide interoperability for microwave access (WiMAX) system using the OFDM scheme, a pilot signal is used to report a CINR in the time domain. When the number of received symbols is sufficient, a conventional CINR estimation is performed. Although CINR estimation is possible using the method, accurate CINR estimation is difficult with the conventional CINR estimation method when the pilot signal is assigned to only one slot duration.

Accordingly, an object of the present invention is to provide a CINR estimation apparatus for a WiMAX system.

In order to achieve the above object of the present invention, a CINR estimating apparatus for a WiMAX system according to an embodiment of the present invention receives a frequency signal converted into a frequency domain and is included in a cluster from the frequency signal. A pilot signal extractor for providing first to fourth pilot signals, the first to fourth pilot signals, and interference included in the second pilot signal using the first to third pilot signals And estimating a first power value of a noise signal and estimating a second power value of an interference and noise signal included in the third pilot signal by using the second to fourth pilot signals. Average power of the signal obtained by averaging the interference and noise signal power values by averaging the second power values, and averaging the second pilot signal and the third pilot signal. And a power estimator for estimating and outputting a data signal power value from a difference between the interference and noise signal power values, and receiving the interference and noise signal power values and the data signal power values to accumulate the interference and noise signal power values. And a signal-to-interference and noise ratio calculation unit that averages and accumulates the data signal power values, and divides the accumulated average data signal power values by the cumulative averaged interference and noise signal power values to calculate and output a signal-to-interference and noise ratio. All.

In example embodiments, the first to fourth pilot signals may be extracted from partial usage of subchannels (PUSC) or full usage of subchannels (FUSC).

In an embodiment, the first pilot signal is a pilot signal included in a second symbol of a first subcarrier in the cluster, and the second pilot signal is a first symbol of a fifth subcarrier in the cluster. And a third pilot signal included in the first symbol of the ninth subcarrier in the cluster, and the fourth pilot signal is a pilot signal included in the second symbol of the thirteenth subcarrier in the cluster. May be a signal.

In an embodiment, the power estimator estimates the first power value by Equation 1, and estimates the second power value by Equation 2, thereby causing the interference and The noise signal power value may be estimated, and the data signal power value may be estimated by Equation 4. Where N (2) represents the first power value, N (3) represents the second power value, and y (1), y (2), y (3) and y (4) are each N _pow represents the interference and noise signal power values, and S _pow represents the data signal power values.

[Equation 1]

[Equation 2]

&Quot; (3) "

&Quot; (4) "

The power estimator may include: a first averager for generating a first average signal by averaging the first pilot signal and the third pilot signal, and averaging the second pilot signal and the fourth pilot signal; A second averager for generating a second average signal, a third averager for averaging the second pilot signal and the third pilot signal to generate a third average signal, and subtracting the first average signal from the second pilot signal A first subtractor for generating a first subtracted signal, a second subtractor for generating a second subtracted signal by subtracting the second average signal from the third pilot signal, and square the first subtracted signal to the first subtractor A first squarer that generates a power value, a second squarer that squares the second subtracted signal to generate the second power value, and a third squarer that squares the third average signal to generate the average power value , remind Subtracting the interference and noise signal power values from the fourth averager and the average power value by averaging a first power value and the second power value to estimate and output the interference and noise signal power values. It may include a third retarder for estimating and outputting the.

In an embodiment, the signal-to-interference and noise ratio calculation unit may accumulate and average the interference and noise signal power values to provide a first cumulative average value, and cumulative average the data signal power values to obtain a second cumulative average value. A second cumulative average to provide the first cumulative average value and a reciprocal calculator for providing a reciprocal value of the first cumulative average value and the output value of the reciprocal operator multiplying the second cumulative average value to provide the signal-to-interference and noise ratio It may include a multiplier.

In order to achieve the above object of the present invention, a CINR estimating apparatus for a WiMAX system according to an embodiment of the present invention receives a frequency signal converted into a frequency domain, a slot to which a pilot signal is allocated A pilot signal extracting unit sequentially providing first to fourth pilot signals included in one cluster, extracted from each of the plurality of nodes), and providing a number of slots to which a pilot signal is allocated; Receiving first to fourth pilot signals, estimating a first power value of an interference and noise signal included in the second pilot signal using the first to third pilot signals, and performing the second to fourth pilot signals First interference by estimating a second power value of the interference and noise signal included in the third pilot signal, and averaging the first power value and the second power value. And estimating and outputting a noise signal power value, and obtaining a first data signal power value from a difference between an average power value of the signal obtained by averaging the second pilot signal and the third pilot signal and the first interference and noise signal power value. A first power estimator for estimating and outputting the first to fourth pilot signals extracted from the first slot and the first to fourth pilot signals extracted from a second slot that is a next slot of the first slot And sequentially receiving the first to fourth pilot signals extracted from the third slot, which is the next slot of the second slot, to obtain power values of the interference and noise signals included in each of the first to fourth pilot signals. And estimate power values of the data signal for each of the first to fourth pilot signals, and transmit the interference and noise signals included in each of the estimated first to fourth pilot signals. Estimating and outputting second interference and noise signal power values by averaging the values, and estimating and outputting second data signal power values by averaging power values of the data signals for each of the estimated first to fourth pilot signals A second power estimator, the first to fourth pilot signals extracted from the first slot, the first to fourth pilot signals extracted from the second slot that is a next slot of the first slot, and The first to fourth pilot signals extracted from the third slot, which is the next slot of the second slot, the first to fourth pilot signals and the fourth pilot signals extracted from the fourth slot, which is the next slot of the third slot. Receiving the first to fourth pilot signals sequentially extracted from the fifth slot, which is the next slot of the four slots, to generate the interference included in each of the first to fourth pilot signals; Estimate power values of a negative signal and power values of a data signal for each of the first to fourth pilot signals, and power values of an interference and noise signal included in each of the estimated first to fourth pilot signals. Estimating and outputting a third interference and noise signal power value by averaging them, and estimating and outputting a third data signal power value by averaging power values of data signals for each of the estimated first to fourth pilot signals. A third power estimator and the first to third interference and noise signal power values, the first to third data signal power values, and the number of slots to which the pilot signal is allocated, to receive the pilot signal; If the number of slots is less than 3, the signal-to-interference and noise ratio are calculated and output using the first interference and noise signal power value and the first data signal power value. When the number of slots to which the pilot signal is allocated is 3 or more and less than 5, the signal-to-interference and noise ratio are calculated and output using the second interference and noise signal power value and the second data signal power value, and the pilot signal is If the allocated number of slots is 5 or more, a signal-to-interference and noise-ratio calculation unit for calculating and outputting signal-to-interference and noise-ratio using the third interference and noise signal power value and the third data signal power value.

In example embodiments, the first to fourth pilot signals may be extracted from partial usage of subchannels (PUSC) or full usage of subchannels (FUSC).

In an embodiment, the first pilot signal is a pilot signal included in a second symbol of a first subcarrier in the cluster, and the second pilot signal is a first symbol of a fifth subcarrier in the cluster. And a third pilot signal included in the first symbol of the ninth subcarrier in the cluster, and the fourth pilot signal is a pilot signal included in the second symbol of the thirteenth subcarrier in the cluster. May be a signal.

In example embodiments, the second power estimator estimates power values of interference and noise signals included in each of the first to fourth pilot signals by Equation 5, and Equation 6 below. Estimate the second interference and noise signal power value by Equation 7 by estimating power values of the data signal for each of the first to fourth pilot signals, and calculate the second data by Equation 8 The signal power value can be estimated. Here, k is an integer of 1 or more and 4 or less, N (k) represents the power value of the interference and noise signal included in the k-th pilot signal, y ₁ (k) is the first extracted from the first slot represents a k pilot signal, y ₂ (k) represents the k-th pilot signal extracted from the second slot, y ₃ (k) represents the k-th pilot signal extracted from the third slot, and S ( k) represents the power value of the data signal for the k-th pilot signal, N _pow represents the second interference and noise signal power value, and S _pow represents the second data signal power value.

[Equation 5]

&Quot; (6) "

[Equation 7]

[Equation 8]

In example embodiments, the third power estimator estimates power values of interference and noise signals included in each of the first to fourth pilot signals by Equation 9, and by Equation 10; Estimate the third interference and noise signal power value by Equation 11 by estimating power values of the data signal for each of the first to fourth pilot signals, and calculate the third data by Equation 12. The signal power value can be estimated. Here, k is an integer of 1 or more and 4 or less, N (k) represents the power value of the interference and noise signal included in the k-th pilot signal, y ₁ (k) is the first extracted from the first slot represents a k pilot signal, y ₂ (k) represents the k-th pilot signal extracted from the second slot, y ₃ (k) represents the k-th pilot signal extracted from the third slot, y ₄ (k) represents the k-th pilot signal extracted from the fourth slot, y ₅ (k) represents the k-th pilot signal extracted from the fifth slot, and S (k) represents the k-th pilot signal. N _pow represents the third interference and noise signal power value, and S _pow represents the third data signal power value.

[Equation 9]

[Equation 10]

[Equation 11]

[Equation 12]

In an embodiment, the signal-to-interference and noise ratio calculation unit accumulates and averages the first interference and noise signal power values to provide a first cumulative average value, and accumulates and averages the first data signal power values. A second cumulative averager providing a cumulative average value, a third cumulative averager providing a third cumulative average value by cumulative averaging the second interference and noise signal power values, and A fourth cumulative averager providing a cumulative average value, a cumulative average of the third interference and noise signal power values, a fifth cumulative averager providing a fifth cumulative average value, and a cumulative average of the third data signal power values Receives a sixth cumulative averager that provides a cumulative average value, the first, third and fifth cumulative average values, and the number of slots to which the pilot signal is allocated; In the case of outputting the first cumulative average value, and outputting the third cumulative average value when the number of slots to which the pilot signal is allocated is 3 or more and less than 5, and when the number of slots to which the pilot signal is allocated is 5 or more, Receiving a first selector for outputting a cumulative average value, the second, fourth and sixth cumulative average values, and the number of slots to which the pilot signal is allocated, and when the number of slots to which the pilot signal is allocated is less than 3, Outputting a second cumulative average value, and outputting the fourth cumulative average value when the number of slots to which the pilot signal is allocated is 3 or more and less than 5; A second selector for outputting, an inverse calculator for receiving an output value of the first selector and providing a reciprocal value of the output value of the first selector and the reciprocal calculator By multiplying the output value and the output value of the second selector can include a multiplier for providing the signal-to-interference-and-noise ratios.

Hereinafter, a signal-to-interference and noise ratio estimation apparatus for a WiMAX system according to embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments. Those skilled in the art will be able to implement the present invention in various other forms without departing from the spirit of the present invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is described, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof. Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

On the other hand, when an embodiment is otherwise implemented, a function or operation specified in a specific block may occur out of the order specified in the flowchart. For example, two consecutive blocks may actually be performed substantially simultaneously, and the blocks may be performed upside down depending on the function or operation involved. Like reference numerals in the drawings denote like elements.

Hereinafter, in the present specification, the "WiMAX system" includes a system that meets the IEEE 802.16e standard including Mobile WiMAX Wave 1 and Mobile WiMAX Wave 2.

FIG. 1 is a diagram illustrating a configuration of received symbols in a world wide interoperability for microwave access (WiMAX) system.

In the WiMAX system, PUSC (partial usage of subchannels) or FUSC (full usage of subchannels) subchannels are composed of symbols in cluster units. FIG. 1 shows a frequency axis (subcarrier index axis) and a time axis. By using (symbol index axis), symbols received in cluster units are shown two-dimensionally. In FIG. 1, white circles represent data signals and black circles represent pilot signals.

Referring to FIG. 1, one cluster 10 includes a second symbol of a first subcarrier, a first symbol of a fifth subcarrier, a first symbol of a ninth subcarrier, and a thirteenth, respectively, within the cluster 10. It includes four pilot signals located in the second symbol of the subcarrier.

FIG. 2 is a block diagram illustrating an apparatus for estimating a signal to interference and noise ratio (CINR) for a WiMAX system according to an embodiment of the present invention.

Referring to FIG. 2, the CINR estimator 1000 for the WiMAX system includes a pilot signal extractor 100, a power estimator 200, and a CINR calculator 300.

The pilot signal extractor 100 receives the frequency signal converted into the frequency domain and provides first to fourth pilot signals pilot1 to pilot4 included in one cluster 10 from the frequency signal.

The power estimator 200 receives the first to fourth pilot signals and uses the first to third pilot signals 20 to calculate power values of the interference and noise signals included in the second pilot signal. Estimate the power values of the interference and noise signals included in the third pilot signal using the second to fourth pilot signals 30, and then include the interference and noise signals included in the estimated second pilot signals. Estimates and outputs the interference and noise signal power values (i & n power) by averaging the power values of and the power values of the interference and noise signals included in the estimated third pilot signal, and outputting the second and third pilot signals. A data signal power value is estimated and output from the difference between the average power value of the averaged signal and the interference and noise signal power values.

The CINR calculation unit 300 receives the interference and noise signal power value and the data signal power value, accumulates the interference and noise signal power value and the data signal power value, respectively, and accumulates the accumulated data signal power. The signal to interference and noise ratio (CINR) is calculated and output by dividing the value by the cumulative averaged interference and noise signal power value.

The first to fourth pilot signals are extracted from a PUSC or FUSC subchannel, and the first pilot signal is a pilot signal included in a second symbol of the first subcarrier in the cluster 10, and the second pilot signal. Is a pilot signal included in the first symbol of the fifth subcarrier in the cluster 10, and the third pilot signal is a pilot signal included in the first symbol of the ninth subcarrier in the cluster 10, and the fourth The pilot signal is a pilot signal included in the second symbol of the thirteenth subcarrier in the cluster 10.

Referring to the operation of the power estimator 200 in detail, the power estimator 200 estimates the power value of the interference and noise signals by applying a linear fitting technique in a cluster 10. Use the estimation method. That is, a signal obtained by subtracting the average signal of the first pilot signal and the third pilot signal from the second pilot signal is estimated as an interference and noise signal included in the second pilot signal. Similarly, a signal obtained by subtracting the average signal of the second pilot signal and the fourth pilot signal from the third pilot signal is estimated as an interference and noise signal included in the third pilot signal.

Specifically, the power value of the interference and noise signal included in the second pilot signal is estimated by Equation 1 below, and the interference and noise included in the third pilot signal by Equation 2 below. Estimate the power value of the noise signal.

[Equation 1]

[Equation 2]

Here, N (2) represents the power value of the interference and noise signal included in the second pilot signal, N (3) represents the power value of the interference and noise signal included in the third pilot signal, and y ( 1), y (2), y (3) and y (4) represent the first to fourth pilot signals, respectively, N _pow represents the interference and noise signal power values, and S _pow represents the data signal power. Indicates a value.

Thereafter, as shown in Equation 3 below, the power value of the interference and noise signal included in the second pilot signal estimated by Equation 1 and the third estimated by Equation 2 The interference and noise signal power values for the received cluster 10 are estimated by averaging the power values of the interference and noise signals included in the pilot signal.

In addition, as shown in Equation 4 below, a signal obtained by averaging the second pilot signal and the third pilot signal is estimated as an average pilot signal for the cluster 10, and the power value of the average pilot signal is calculated. The data signal power values for the received cluster 10 are estimated by subtracting the interference and noise signal power values.

&Quot; (3) "

&Quot; (4) "

Where N _pow represents the interference and noise signal power values and S _pow represents the data signal power values.

3 is a block diagram illustrating an exemplary configuration of the power estimator 200 of FIG. 2.

Referring to FIG. 3, the power estimator 200 includes a first averager 210, a first adder 220, a first squarer 230, a second averager 240, and a second adder ( 250, a second squarer 260, a third averager 280, a fourth averager 270, a third squarer 290, and a third adder / retractor 295.

The first averager 210 averages the first pilot signal and the third pilot signal to generate a first average signal, and the first adder 220 converts the first average signal from the second pilot signal. Subtract the first subtracted signal to generate a first subtracted signal, and the first squarer 230 squares the first subtracted signal to estimate power values of interference and noise signals included in the second pilot signal.

In addition, the second averager 240 averages the second pilot signal and the fourth pilot signal to generate a second average signal, and the second adder 250 performs the second average from the third pilot signal. Subtracting the signal generates a second subtracted signal, and the second squarer 260 squares the second subtracted signal to estimate power values of the interference and noise signals included in the third pilot signal.

The fourth averager 270 is applied to the third pilot signal which is the output value of the power and the second squarer 260 of the interference and noise signals included in the second pilot signal output value of the first squarer 230. The power values of the interference and noise signals included are averaged to estimate and output the interference and noise signal power values for the cluster 10.

The third averager 280 averages the second pilot signal and the third pilot signal to estimate an average pilot signal for the cluster 10, and the third squarer 290 squares the average pilot signal. Estimating a power value of the average pilot signal, and the third adder / lower 295 is the interference value that is the output value of the fourth averager 270 at the power value of the average pilot signal that is the output value of the third squarer 290 and The noise signal power value is subtracted to estimate and output the data signal power value for the cluster 10.

As described above, the power estimator 200 of FIG. 3 includes a first averager 210, a first adder 220, a first squarer 230, a second averager 240, and a second adder / lower. Group 250, the second squarer 260, the third averager 280, the fourth averager 270, the third squarer 290 and the third adder and subtractor 295 has been described as including According to the embodiment, the power estimator 200 may be implemented in another configuration that satisfies [Equation 1], [Equation 2], [Equation 3] and [Equation 4].

4 is a block diagram illustrating an exemplary configuration of the CINR calculation unit 300 of FIG. 2.

Referring to FIG. 4, the CINR calculation unit 300 includes a first cumulative averager 310, a second cumulative averager 320, an inverse operator 330, and a multiplier 340.

The first cumulative averager 310 provides a cumulative average value of the interference and noise signal power values, and the second cumulative averager 320 provides a cumulative average value of the data signal power values. Reference numeral 330 provides a value corresponding to the inverse of the output value of the first cumulative averager 310, and the multiplier 340 multiplies the output value of the inverse operator 330 by the output value of the second cumulative averager 320. Provide the CINR.

As described above, the CINR calculation unit 300 provides the CINR by dividing the cumulative average value of the data signal power values for each cluster by the cumulative average value of the interference and noise signal power values for each cluster.

Although the CINR calculation unit 300 of FIG. 4 has been described as including a first cumulative averager 310, a second cumulative averager 320, an inverse operator 330, and a multiplier 340, according to an embodiment, The CINR calculation unit 300 may be implemented in another configuration that provides the CINR by dividing the cumulative average value of the data signal power values for each cluster by the cumulative average value of the interference and noise signal power values for each cluster. .

Through the configuration and operation as described above, the CINR estimation apparatus 1000 for the WiMAX system according to an embodiment of the present invention performs CINR estimation on a cluster basis, whereby a pilot signal is allocated to only one slot period. In this case, the linear fitting technique can be applied within the cluster to provide an accurate CINR estimate.As the number of slots to which the pilot signal is allocated increases, the interference and noise signal power values and the data signal power values for each cluster are accumulated and averaged. The accuracy of CINR estimation can be further increased.

5 is a block diagram illustrating an apparatus for estimating CINR for a WiMAX system according to another embodiment of the present invention.

Referring to FIG. 5, a CINR estimator 2000 for a WiMAX system includes a pilot signal extractor 2100, a first power estimator 2200, a second power estimator 2300, and a third power estimator 2400. ) And a CINR calculation unit 2500.

The pilot signal extractor 2100 receives the frequency signal converted into the frequency domain and extracts the pilot signal from each of the slots to which the pilot signal is assigned, and includes the first to fourth parts included in the cluster 10. The pilot signals pilot1 to pilot4 are sequentially provided, and the number of slots to which the pilot signal is allocated is provided. Here, the number of slots to which the pilot signal is allocated means the number of slots from which the pilot signal extractor 2100 extracts the first to fourth pilot signals from the received frequency signal.

The first power estimator 2200 receives the first to fourth pilot signals extracted from the first slot, and is included in the second pilot signal using the first to third pilot signals 20. Estimate the power value of the interference and noise signal and estimate the power value of the interference and noise signal included in the third pilot signal using the second to fourth pilot signals 30, By averaging the power values of the interference and noise signals included in the signal and the power values of the interference and noise signals included in the estimated third pilot signal, the first interference and noise signal power values i & n power 1 are estimated and output. The first data signal power value data power 1 is estimated and output from a difference between an average power value of the signal obtained by averaging the second pilot signal and the third pilot signal and the first interference and noise signal power values.

The second power estimator 2300 may include the first to fourth pilot signals extracted from the first slot, the first to fourth pilot signals extracted from a second slot that is a next slot of the first slot, and The first to fourth pilot signals sequentially extracted from the third slot that is the next slot of the second slot are sequentially received.

Thereafter, the second power estimator 2300 uses the first pilot signal extracted from the first slot, the first pilot signal extracted from the second slot, and the first pilot signal extracted from the third slot. Estimating a power value of an interference and noise signal included in the first pilot signal and a power value of a data signal for the first pilot signal, and extracting a second pilot signal extracted from the first slot and the second slot Estimating power values of interference and noise signals included in the second pilot signal and power values of the data signal for the second pilot signal using the second pilot signal and the second pilot signal extracted from the third slot. And a third pilot signal extracted from the first slot, a third pilot signal extracted from the second slot, and a third pilot signal extracted from the third slot. Estimating a power value of an interference and noise signal included in the third pilot signal and a power value of a data signal for the third pilot signal, and extracting the fourth pilot signal extracted from the first slot and the second slot. Using the extracted fourth pilot signal and the fourth pilot signal extracted from the third slot, power values of the interference and noise signals included in the fourth pilot signal and power values of the data signal for the fourth pilot signal are obtained. Estimate.

Thereafter, the second power estimator 2300 averages the power values of the interference and noise signals included in each of the estimated first to fourth pilot signals, thereby obtaining a second interference and noise signal power value (i & n power 2). And output a second data signal power value (data power 2) by averaging the power values of the data signal for each of the estimated first to fourth pilot signals.

The third power estimator 2400 may extract the first to fourth pilot signals extracted from the first slot and the first to fourth pilot signals extracted from the second slot that is a next slot of the first slot. The first to fourth pilot signals extracted from the third slot that is a next slot of the second slot, the first to fourth pilot signals extracted from a fourth slot that is a next slot of the third slot, and The first to fourth pilot signals sequentially extracted from the fifth slot that is the next slot of the fourth slot are sequentially received.

Thereafter, the third power estimator 2400 may include a first pilot signal extracted from the first slot, a first pilot signal extracted from the second slot, a first pilot signal extracted from the third slot, and the first power signal. By using the first pilot signal extracted from the fourth slot and the first pilot signal extracted from the fifth slot, the power value of the interference and noise signals included in the first pilot signal and the data signal for the first pilot signal Estimating a power value, a second pilot signal extracted from the first slot, a second pilot signal extracted from the second slot, a second pilot signal extracted from the third slot, and a second extracted from the fourth slot Power values of the interference and noise signals included in the second pilot signal and the second pilot signal using a second pilot signal and a second pilot signal extracted from the fifth slot; Estimating a power value of a data signal for the third data signal, a third pilot signal extracted from the first slot, a third pilot signal extracted from the second slot, a third pilot signal extracted from the third slot, and the fourth slot Power values of the interference and noise signals included in the third pilot signal and power values of the data signals for the third pilot signals using the third pilot signals extracted from the third pilot signal and the third pilot signals extracted from the fifth slot. Estimate the fourth pilot signal extracted from the first slot, the fourth pilot signal extracted from the second slot, the fourth pilot signal extracted from the third slot, and the fourth pilot extracted from the fourth slot. The power value of the interference and noise signals included in the fourth pilot signal using the fourth pilot signal extracted from the signal and the fifth slot and the fourth It estimates a power value of the data signal for the pilot signal.

Thereafter, the third power estimator 2400 averages the power values of the interference and noise signals included in each of the estimated first to fourth pilot signals, thereby generating a third interference and noise signal power value i & n power 3. Is estimated and output, and the third data signal power value (data power 3) is estimated and output by averaging the power values of the data signals for each of the estimated first to fourth pilot signals.

The CINR calculator 2500 receives the first to third interference and noise signal power values, the first to third data signal power values, and the number of slots to which the pilot signal is allocated, and allocates the pilot signal. If the number of slots is less than 3, the signal-to-interference and noise ratio (CINR) is calculated by using the first interference and noise signal power values and the first data signal power values, which are output values of the first power estimation unit 2200, and are output. If the number of slots to which the pilot signal is allocated is 3 or more and less than 5, signal-to-interference using the second interference and noise signal power values and the second data signal power values, which are output values of the second power estimator 2300, is performed. And calculating and outputting a noise ratio (CINR), and when the number of slots to which the pilot signal is allocated is 5 or more, the third interference and noise signal power values, which are output values of the third power estimator 2400, and the The signal-to-interference and noise ratio (CINR) is calculated and output using the third data signal power value.

Like the CINR estimation apparatus 1000 for the WiMAX system of FIG. 2, the first to fourth pilot signals are extracted from a PUSC or FUSC subchannel, and the first pilot signal is the first subcarrier in the cluster 10. Is a pilot signal included in the second symbol of, and the second pilot signal is a pilot signal included in the first symbol of the fifth subcarrier in the cluster 10, and the third pilot signal is nine in the cluster 10. The pilot signal is included in the first symbol of the first subcarrier, and the fourth pilot signal is the pilot signal included in the second symbol of the thirteenth subcarrier in the cluster 10.

The first power estimator 2200 of FIG. 5 is the same as the power estimator 200 of FIG. 2, and only names of output signals are different. Since the configuration and operation of the power estimation unit 200 have been described in detail with reference to FIGS. 2 and 3, a detailed description of the configuration and operation of the first power estimation unit 2200 will be omitted.

Referring to the operation of the second power estimator 2300 in detail, the second power estimator 2300 may perform the previous pilot signal, the current pilot signal, and the next pilot on the time axis for each of the first to fourth pilot signals. Interference and noise included in each of the first to fourth pilot signals by performing linear fitting on each of the first to fourth pilot signals on a time axis under the assumption that the channel of the signal changes linearly. The second interference and noise signal power values are estimated by estimating power values of the signal and averaging power values of the interference and noise signals included in each of the first to fourth pilot signals.

Specifically, the power values of the interference and noise signals included in the k-th pilot signal are estimated by Equation 5 below.

[Equation 5]

Here, k is an integer of 1 or more and 4 or less, N (k) represents the power value of the interference and noise signal included in the k-th pilot signal, y ₁ (k) is the first extracted from the first slot represents a k pilot signal, y ₂ (k) represents the k-th pilot signal extracted from the second slot, and y ₃ (k) represents the k-th pilot signal extracted from the third slot.

As shown in Equation 5, the k-th pilot signal extracted from the first slot and the k-th pilot signal extracted from the third slot in the k-th pilot signal extracted from the second slot The power value of the interference and noise signal included in the k-th pilot signal is estimated by subtracting the average value from the interference and noise signal included in the k-th pilot signal and squaring them. In this case, when performing the linear fitting in the WiMAX system, the pilot signal has a magnitude equal to 1.5 times the noise power, and as shown in Equation 5, the pilot signal is included in the k-th pilot signal by multiplying 2/3. Estimate the power values of the interference and noise signals.

In addition, the second power estimator 2300 may include interference and noise included in the estimated kth pilot signal at a power value of the kth pilot signal extracted from the second slot, as shown in Equation 6 below. The power value of the data signal for the k-th pilot signal is estimated by subtracting the power value of the signal.

&Quot; (6) "

Here, S (k) represents the power value of the data signal with respect to the kth pilot signal.

As shown in Equation 7 below, the second power estimator 2300 averages the power values of interference and noise signals included in the first to fourth pilot signals estimated through Equation 5, By estimating a second interference and noise signal power value and averaging the power values of the data signal for the first to fourth pilot signals estimated through Equation 6, as shown in Equation 8 below. The second data signal power value is estimated.

[Equation 7]

[Equation 8]

Here, N _pow represents the second interference and noise signal power value, and S _pow represents the second data signal power value.

6 is a block diagram illustrating an exemplary configuration of the second power estimator 2300 of FIG. 5.

Referring to FIG. 6, the second power estimator 2300 may include first to eighth delays 2301, 2303, 2321, 2323, 2341, 2343, 2361, and 2363, and first to sixth averagers 2305 and 2325. , 2345, 2365, 2381, 2383, 1st to 8th retarders 2307, 2327, 2347, 2367, 2315, 2335, 2355, 2375, 1st to 8th squarers (2309, 2313, 2329, 2333 , 2349, 2353, 2369, 2373 and first to fourth gain adjusters 2311, 2331, 2351, 2371.

Through the configuration as shown in FIG. 6, the second power estimator 2300 implements the operations of Equation 5, Equation 6, Equation 7, and Equation 8.

Specifically, the first to fourth gain adjusters 2311, 2331, 2351, and 2371 output power values of the interference and noise signals included in the first to fourth pilot signals, respectively, and the fifth to eighth regulators. 2315, 2335, 2355, and 2375 output power values of data signals with respect to the first to fourth pilot signals, respectively. The fifth averager 2381 estimates and outputs the second interference and noise signal power values by averaging power values of the interference and noise signals included in the first to fourth pilot signals, and outputs a sixth averager 2383. ) Estimates and outputs the second data signal power value by averaging the power values of the data signals with respect to the first to fourth pilot signals.

According to an embodiment, the second power estimator 2300 may have a configuration different from that of FIG. 6, which implements the operations of Equation 5, Equation 6, Equation 7, and Equation 8. It may be implemented.

When the operation of the third power estimator 2400 is described in detail, the third power estimator 2400 may include two previous pilot signals and a current pilot signal on the time axis for each of the first to fourth pilot signals. And a mean square error (MSE) using five pilot signals adjacent in time on each of the first to fourth pilot signals under the assumption that a channel change of the next two pilot signals follows a 2nd polynomial. Estimates power values of the interference and noise signals included in each of the first to fourth pilot signals by performing a second polynomial fitting so that is minimized, and applies to each of the first to fourth pilot signals. The third interference and noise signal power values are estimated by averaging the power values of the included interference and noise signals.

Specifically, the power values of the interference and noise signals included in the k-th pilot signal are estimated by Equation 9 below.

[Equation 9]

Here, k is an integer of 1 or more and 4 or less, N (k) represents the power value of the interference and noise signal included in the k-th pilot signal, y ₁ (k) is the first extracted from the first slot represents a k pilot signal, y ₂ (k) represents the k-th pilot signal extracted from the second slot, y ₃ (k) represents the k-th pilot signal extracted from the third slot, y ₄ (k) represents the k-th pilot signal extracted from the fourth slot, and y ₅ (k) represents the k-th pilot signal extracted from the fifth slot.

In addition, the third power estimator 2400 may include interference and noise included in the estimated kth pilot signal at a power value of the kth pilot signal extracted from the third slot, as shown in Equation 10 below. The power value of the data signal for the k-th pilot signal is estimated by subtracting the power value of the signal.

[Equation 10]

Here, S (k) represents the power value of the data signal with respect to the kth pilot signal.

Thereafter, the third power estimator 2400 calculates power values of the interference and noise signals included in the first to fourth pilot signals estimated through Equation 9, as shown in Equation 11 below. The third interference and noise signal power values are estimated by averaging, and the power values of the data signals for the first to fourth pilot signals estimated through Equation 10 are calculated as shown in Equation 12 below. The third data signal power value is estimated by averaging.

[Equation 11]

[Equation 12]

Here, N _pow represents the third interference and noise signal power value, and S _pow represents the third data signal power value.

FIG. 7 is a block diagram illustrating an exemplary configuration of the CINR calculation unit 2500 of FIG. 5.

Referring to FIG. 7, the CINR calculator 2500 may include first to sixth cumulative averagers 2510, 2520, 2530, 2540, 2550, and 2560, a first selector 2570, a second selector 2580, and reciprocal. It includes an operator 2590 and a multiplier 2595.

The first to sixth cumulative averagers 2510, 2520, 2530, 2540, 2550, and 2560 respectively represent the first interference and noise signal power values, the first data signal power values, and the second interference and noise signal power values, respectively. The cumulative average of the second data signal power value, the third interference and noise signal power value, and the third data signal power value are provided to provide first to sixth cumulative average values, respectively.

The first selector 2570 receives the first, third and fifth cumulative average values and the number of slots to which the pilot signal is allocated, and when the number of slots to which the pilot signal is allocated is less than 3, the first cumulative average value. The third cumulative average value is output when the number of slots to which the pilot signal is allocated is 3 or more and less than 5, and the fifth cumulative average value is output when the number of slots to which the pilot signal is allocated is 5 or more.

The second selector 2580 receives the second, fourth and sixth cumulative average values and the number of slots to which the pilot signal is allocated, and when the number of slots to which the pilot signal is allocated is less than 3, the second cumulative average value. The fourth cumulative average value is output when the number of slots to which the pilot signal is allocated is 3 or more and less than 5, and the sixth cumulative average value is output when the number of slots to which the pilot signal is allocated is 5 or more.

A reciprocal operator 2590 receives the output value of the first selector and provides an inverse value of the output value of the first selector, and the multiplier 2595 outputs the output value of the reciprocal operator 2590 and the output value of the second selector. Multiply to give the CINR.

As described above, the CINR calculation unit 2500 calculates a cumulative averaged interference and noise signal power value and a cumulative averaged data signal power value to be used for the CINR estimation according to the number of slots to which the pilot signal is allocated. Selected from among the output values from the government unit 2200, the output values from the second power estimator 2300, and the cumulative average values for each of the output values from the third power estimator 2400.

FIG. 8 illustrates that the CINR calculation unit 2500 of FIG. 5 performs CINR estimation among the output values from the first power estimator 2200, the second power estimator 2300, and the third power estimator 2400 of FIG. 5. This flowchart shows how to select the output values to use.

Since the second power estimator 2300 estimates the second interference and noise signal power value and the second data signal power value by performing linear fitting through three successive pilot signals in time, they are included in one cluster. The accuracy of the estimation is higher than that of the first power estimator 2200 that estimates using the pilot signal. In addition, since the third power estimator 2400 estimates the third interference and noise signal power value and the third data signal power value by performing a second order polynomial fitting through five consecutive pilot signals. The accuracy of the estimation is higher than that of the second power estimator 2300 estimated through the linear fitting.

However, the second power estimator 2300 may output the second interference and noise signal power value and the second data signal power value only when there are at least three slots to which a pilot signal is allocated, and the third power The estimator 2400 may output the third interference and noise signal power value and the third data signal power value only when at least five slots to which a pilot signal is allocated exist.

Accordingly, as shown in FIG. 8, when the number of slots to which the pilot signal is allocated is less than 3, the CINR calculator 2500 uses output values of the first power estimator 2200 to which the cluster-based algorithm is applied (S3100). When the number of slots to which the pilot signal is allocated is 3 or more and less than 5, the output values of the second power estimator 2300 to which the linear fitting algorithm is applied are used (S3200), and when the number of slots to which the pilot signal is allocated is 5 or more. The output values of the third power estimator 2400 to which the second order polynomial fitting algorithm is applied are used (S3300).

Through the above-described configuration and operation, the CINR estimation apparatus 2000 for the WiMAX system according to another embodiment of the present invention applies the CINR by applying a cluster-based algorithm when the number of slots to which a pilot signal is allocated is less than three. When the number of slots to which the pilot signal is allocated is 3 or more, the CINR estimation is performed by applying a linear fitting algorithm on the time axis. When the number of slots to which the pilot signal is allocated is 5 or more, the second order polynomial algorithm Apply to perform CINR estimation. Therefore, even when the pilot signal is assigned only one slot period, the linear fitting technique can be applied within the cluster to provide an accurate CINR estimate, and the higher the number of slots to which the pilot signal is allocated, the more accurate the estimation method is. Optionally, high accuracy CINR estimates can be provided.

Meanwhile, the second power estimator 2300 and the third power estimator 2400 use a method of estimating interference and noise signal components by applying linear fitting or quadratic polynomial fitting to time-sequential pilot signals. Therefore, the operation may be performed even in a subchannel in which symbols are not configured in cluster units. Therefore, in the case of a subchannel in which symbols are not configured in cluster units, WiMAX includes a pilot signal extractor 2100, a second power estimator 2300, a third power estimator 2400, and a CINR calculator 2500. A CINR estimation apparatus for the system may be implemented.

9 is a block diagram illustrating an OFDM receiver for a WiMAX system according to an embodiment of the present invention.

9, an OFDM receiver 4000 for a WiMAX system includes a frequency converter 4100, a Fourier transform 4200, a channel estimator 4300, a channel equalizer 4400, and a CINR estimator 4500. And a demodulator 4600.

The frequency converter 4100 receives a high frequency signal from an antenna and converts the signal into a baseband signal, and the Fourier transformer 4200 transforms the baseband signal into a frequency signal by converting the baseband signal into a frequency signal. The channel equalizer 4400 receives the frequency signal to perform channel estimation and provides a channel estimation result. The channel equalizer 4400 receives the frequency signal and the channel estimation result to compensate for the distorted channel characteristics to provide a compensated signal. The grandfather 4600 receives the compensated signal to perform data demodulation, and the CINR estimator 4500 receives the frequency signal and uses the first to fourth pilot signals included in a cluster to signal to interference and noise ratio. Outputs

The CINR estimator 4500 of FIG. 9 may be a CINR estimator 1000 for the WiMAX system of FIG. 2 or a CINR estimator 2000 for the WiMAX system of FIG. 5. Since the configuration and operation of the CINR estimation apparatuses 1000 and 2000 for the WiMAX system have been described in detail with reference to FIGS. 2 and 5, a detailed description of the configuration and operation of the CINR estimation unit 4500 will be omitted. .

The CINR estimation apparatus and the OFDM receiver including the same for the WiMAX system according to an embodiment of the present invention can provide an accurate CINR estimation value by applying a linear fitting technique in a cluster even when a pilot signal is allocated to only one slot period. As the number of slots to which a pilot signal is allocated increases, a higher accuracy CINR estimate can be provided by selectively applying a higher accuracy estimation method, which can be effectively used in a WiMAX system.

As described above, the present invention has been described with reference to a preferred embodiment of the present invention, but those skilled in the art may vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be understood that modifications and changes can be made.

FIG. 1 is a diagram illustrating a configuration of received symbols in a world wide interoperability for microwave access (WiMAX) system.

FIG. 2 is a block diagram illustrating an apparatus for estimating a signal to interference and noise ratio (CINR) for a WiMAX system according to an embodiment of the present invention.

3 is a block diagram illustrating a configuration of a power estimation unit of FIG. 2.

4 is a block diagram illustrating a configuration of the CINR calculation unit of FIG. 2.

5 is a block diagram illustrating an apparatus for estimating CINR for a WiMAX system according to another embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a second power estimator of FIG. 5.

FIG. 7 is a block diagram illustrating a configuration of the CINR calculation unit of FIG. 5.

FIG. 8 is a flowchart illustrating a method of selecting, by the CINR calculation unit of FIG. 5, output values to be used for CINR estimation among output values from the first power estimation unit, the second power estimation unit, and the third power estimation unit of FIG. 5.

9 is a block diagram illustrating an OFDM receiver for a WiMAX system according to an embodiment of the present invention.

Claims (12)

A pilot signal extracting unit which receives the frequency signal converted into the frequency domain and provides first to fourth pilot signals included in one cluster from the frequency signal; Receiving the first to fourth pilot signals, using the first to third pilot signals to estimate the first power value of the interference and noise signal included in the second pilot signal and the second to fourth pilot Estimating a second power value of the interference and noise signal included in the third pilot signal using the signals, estimating and outputting an interference and noise signal power value by averaging the first power value and the second power value; A power estimator configured to estimate and output a data signal power value from a difference between an average power value of the signal obtained by averaging the second pilot signal and the third pilot signal and the interference and noise signal power values; And The interference and noise signal power value and the data signal power value are received, the interference and noise signal power value is cumulatively averaged, and the data signal power value is cumulatively averaged, and the cumulative averaged data signal power value is the cumulative average. And a signal-to-interference and noise ratio calculation unit for calculating and outputting a signal-to-interference and noise ratio by dividing by the interference and noise signal power values. The first pilot signal is a pilot signal included in a second symbol of the first subcarrier in the cluster, and the second pilot signal is a pilot signal included in the first symbol of a fifth subcarrier in the cluster. And the third pilot signal is a pilot signal included in the first symbol of the ninth subcarrier in the cluster, and the fourth pilot signal is a pilot signal included in the second symbol of the thirteenth subcarrier in the cluster. Signal-to-interference and noise ratio estimator for a World Wide Interoperability for Microwave Access (WiMAX) system. The method of claim 1, wherein the first to fourth pilot signals, Signal-to-interference and noise ratio estimation apparatus for the WiMAX system, characterized in that extracted from the PUSC (partial usage of subchannels) or FUSC (full usage of subchannels) subchannels. delete The method of claim 1, wherein the power estimator, The first power value is estimated by Equation 1, the second power value is estimated by Equation 2, and the interference and noise signal power value is estimated by Equation 3, Equation 4] the signal-to-interference and noise ratio estimation apparatus for the WiMAX system, characterized in that for estimating the data signal power value (where N (2) represents the first power value, N (3) is Y (1), y (2), y (3) and y (4) represent the first to fourth pilot signals, respectively, and N _pow represents the interference and noise signal power values. S _pow represents the data signal power value. [Equation 1]

[Equation 2]

&Quot; (3) "

&Quot; (4) "

The method of claim 1, wherein the power estimator, A first averager for averaging the first pilot signal and the third pilot signal to generate a first average signal;  A second averager which averages the second pilot signal and the fourth pilot signal to generate a second average signal;  A third averager for averaging the second pilot signal and the third pilot signal to generate a third average signal; A first adder and a subtractor for generating a first subtracted signal by subtracting the first average signal from the second pilot signal; A second adder / subtractor for generating a second subtracted signal by subtracting the second average signal from the third pilot signal; A first squarer that squares the first subtracted signal to produce the first power value; A second squarer that squares the second subtracted signal to produce the second power value; A third squarer that squares the third average signal to generate the average power value; A fourth averager for averaging the first power value and the second power value to estimate and output the interference and noise signal power values; And And a third adder and a subtractor for estimating and outputting the data signal power value by subtracting the interference and noise signal power value from the average power value. The method of claim 1, wherein the signal to interference and noise ratio calculator, A first cumulative averager which accumulates the interference and noise signal power values to provide a first cumulative average value; A second cumulative averager which accumulates the data signal power values to provide a second cumulative average value; A reciprocal calculator configured to receive the first cumulative average value and provide an inverse value of the first cumulative average value; And And a multiplier for multiplying the output value of the reciprocal operator by the second cumulative average value to provide the signal-to-interference and noise ratio. Receiving a frequency signal converted into a frequency domain, sequentially providing first to fourth pilot signals included in a cluster, extracted from each of slots to which a pilot signal is allocated; A pilot signal extracting unit providing a number of slots to which a pilot signal is allocated; Receiving the first to fourth pilot signals extracted from the first slot, using the first to third pilot signals to estimate the first power value of the interference and noise signals included in the second pilot signal and the First interference and noise by estimating a second power value of the interference and noise signal included in the third pilot signal using second to fourth pilot signals and averaging the first power value and the second power value Estimate and output a signal power value, estimate a first data signal power value from a difference between an average power value of the signal obtained by averaging the second pilot signal and the third pilot signal, and the first interference and noise signal power value; A first power estimator for outputting; The first to fourth pilot signals extracted from the first slot, the first to fourth pilot signals extracted from the second slot that is the next slot of the first slot, and the next slot of the second slot. Sequentially receiving the first to fourth pilot signals extracted from the three slots, the power values of the interference and noise signals included in each of the first to fourth pilot signals, and the first to fourth pilot signals. Estimating and outputting power values of the data signal for each, estimating and outputting the second interference and noise signal power values by averaging the power values of the interference and noise signals included in each of the estimated first to fourth pilot signals; A second power estimator for estimating and outputting a second data signal power value by averaging power values of data signals for each of the estimated first to fourth pilot signals; The first to fourth pilot signals extracted from the first slot, the first to fourth pilot signals extracted from the second slot which is the next slot of the first slot, and the next slot of the second slot. The first to fourth pilot signals extracted from the third slot, the first to fourth pilot signals extracted from the fourth slot that is the next slot of the third slot, and the next slot of the fourth slot. Sequentially receiving the first to fourth pilot signals extracted from the five slots, the power values of the interference and noise signals included in each of the first to fourth pilot signals, and the first to fourth pilot signals. Estimate the power values of the data signal for each and average the power values of the interference and noise signals included in each of the estimated first to fourth pilot signals before Estimating a value to the output, and the estimated first to the fourth power by averaging the value of the data signal for the pilot signal, each third third power estimator for estimating and outputting the data signal power value; And When the first to third interference and noise signal power values, the first to third data signal power values and the number of slots to which the pilot signal is allocated are received, and the number of slots to which the pilot signal is allocated is less than three. Calculate and output a signal-to-interference and noise ratio using the first interference and noise signal power value and the first data signal power value, and the second interference when the number of slots to which the pilot signal is allocated is 3 or more and less than 5 And calculating and outputting a signal-to-interference and noise ratio using the noise signal power value and the second data signal power value, and when the number of slots to which the pilot signal is allocated is 5 or more, the third interference and noise signal power value and the WiMAX system including a signal-to-interference and noise ratio calculation unit for calculating and outputting the signal-to-interference and noise ratio using the third data signal power value Signal to Interference and Noise Ratio Estimation System The method of claim 7, wherein the first to fourth pilot signals, Signal-to-interference and noise ratio estimation apparatus for the WiMAX system, characterized in that extracted from the PUSC (partial usage of subchannels) or FUSC (full usage of subchannels) subchannels. 8. The method of claim 7, The first pilot signal is a pilot signal included in a second symbol of the first subcarrier in the cluster, The second pilot signal is a pilot signal included in the first symbol of the fifth subcarrier in the cluster, The third pilot signal is a pilot signal included in the first symbol of the ninth subcarrier in the cluster, And the fourth pilot signal is a pilot signal included in a second symbol of a thirteenth subcarrier in the cluster. The method of claim 7, wherein the second power estimator, The power values of the interference and noise signals included in each of the first to fourth pilot signals are estimated by Equation 5, and the equations for each of the first to fourth pilot signals are expressed by Equation 6. Estimating the second interference and noise signal power value by Equation 7 by estimating power values of a data signal, and estimating the second data signal power value by Equation 8 Signal-to-interference and noise ratio estimator for a system, where k is an integer greater than or equal to 1 and less than or equal to 4, N (k) represents the power value of the interference and noise signal included in the kth pilot signal, and y ₁ (k) is Represents the kth pilot signal extracted from the first slot, y ₂ (k) represents the kth pilot signal extracted from the second slot, and y ₃ (k) represents the extracted from the third slot Represents a k-th pilot signal, and S (k) is Power value of the data signal for the kth pilot signal, N _pow represents the second interference and noise signal power value, and S _pow represents the second data signal power value. [Equation 5]

&Quot; (6) "

[Equation 7]

[Equation 8]

The method of claim 7, wherein the third power estimator, Equation (9) estimates power values of the interference and noise signals included in each of the first to fourth pilot signals, and Equation (10) for each of the first to fourth pilot signals. Estimate the third interference and noise signal power value by [Equation 11] by estimating the power values of the data signal, and estimates the third data signal power value by [Equation 12] Signal-to-interference and noise ratio estimator for a system, where k is an integer greater than or equal to 1 and less than or equal to 4, N (k) represents the power value of the interference and noise signal included in the kth pilot signal, and y ₁ (k) is Represents the kth pilot signal extracted from the first slot, y ₂ (k) represents the kth pilot signal extracted from the second slot, and y ₃ (k) represents the extracted from the third slot Represents a kth pilot signal, and y ₄ ( k) represents the k-th pilot signal extracted from the fourth slot, y ₅ (k) represents the k-th pilot signal extracted from the fifth slot, and S (k) represents the k-th pilot signal. N _pow represents the third interference and noise signal power value, and S _pow represents the third data signal power value. [Equation 9]

[Equation 10]

[Equation 11]

[Equation 12]

The method of claim 7, wherein the signal to interference and noise ratio calculator, A first cumulative averager which accumulates the first interference and noise signal power values to provide a first cumulative average value; A second cumulative averager which accumulates the first data signal power value to provide a second cumulative average value; A third cumulative averager which accumulates the second interference and noise signal power values to provide a third cumulative average value; A fourth cumulative averager which accumulates the second data signal power value to provide a fourth cumulative average value; A fifth cumulative averager which accumulates the third interference and noise signal power values to provide a fifth cumulative average value; A sixth cumulative averager which accumulates the third data signal power value to provide a sixth cumulative average value; Receiving the first, third and fifth cumulative average values and the number of slots to which the pilot signal is allocated, and outputting the first cumulative average value when the number of slots to which the pilot signal is allocated is less than three, and outputs the pilot signal. A first selector for outputting the third cumulative average value when the number of allocated slots is 3 or more and less than 5, and outputting the fifth cumulative average value when the number of slots to which the pilot signal is allocated is 5 or more;  The second, fourth and sixth cumulative average values and the number of slots to which the pilot signal is allocated are received. When the number of slots to which the pilot signal is allocated is less than 3, the second cumulative average value is output and the pilot signal is output. A second selector for outputting the fourth cumulative average value when the number of slots allocated is 3 or more and less than 5 and outputting the sixth cumulative average value when the number of slots to which the pilot signal is allocated is 5 or more; A reciprocal calculator for receiving an output value of the first selector and providing an inverse value of the output value of the first selector; And And a multiplier for multiplying the output value of the reciprocal operator by the output value of the second selector to provide the signal-to-interference and noise ratio.

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