KR20100091390A - Apparatus and method for velocity estimation on a mobile station in wireless communication system - Google Patents

Abstract

PURPOSE: An apparatus and a method for estimating speed on a terminal in a wireless communication system are provided to estimate speed through channel information transmitted from a base station, thereby estimating speed of the terminal without additional overhead. CONSTITUTION: A subtractor(202) subtracts the (k-1)th CQI value, inputted from a delay device(200), from kth CQI value from a CQI(Channel Quality Indicator) demodulator. An absolute value calculator(204) obtains an absolute value of a value from the substractor. The first filter(206) performs IIR(Infinite Impulse Response) filtering of a value of the absolute value calculator. The second filter(208) performs IIR filtering of the absolute value calculator. A speed determining unit(210) determines moving speed of a corresponding terminal.

Description

Apparatus and method for estimating the speed of a terminal in a wireless communication system {APPARATUS AND METHOD FOR VELOCITY ESTIMATION ON A MOBILE STATION IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for estimating the speed of a terminal in a wireless communication system, and more particularly, to an apparatus and a method for estimating the speed of a terminal using channel information in a broadband wireless communication system.

Today, many wireless communication technologies are proposed as candidates for high-speed mobile communication. Among them, Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) is the most powerful next generation wireless communication technology. It is recognized as. It is expected that the above-mentioned OFDM / OFDMA technology will be used in most future wireless communication technologies.

Meanwhile, next-generation wireless communication systems require resource allocation based on accurate channel information in order to support a large capacity multimedia packet service within limited frequency and channel resources. In the case of time-varying channels such as mobile communication channels, the speed factor is very important as information about the channel. In other words, speed information is information indicating a channel state of a user and is essential for efficient operation of system resources.

Speed information of the terminal in the mobile communication system may be used in various fields to improve the performance of the system. For example, when speed information is used in an adaptive transmission / reception technique, a receiver may perform more efficient channel estimation, and the transmitter may adjust modulation, coding, or a multi-antenna signal transmission scheme to a channel state. As another example, when used in an algorithm on the network side, handover decisions can be made more accurately and system resources can be managed efficiently.

According to the prior art, the receiver estimates the maximum Doppler frequency using a change in the magnitude of a predetermined signal (eg, a pilot signal or a constant envelop signal) received, and estimates a moving speed using the estimated Doppler frequency.

However, such a speed estimating technique must transmit a reference signal (pilot signal) from the transmitter. If data is transmitted only in the downlink without transmitting the data in the uplink, the base station cannot estimate the speed of the terminal. In this case, speed estimation can be performed using the uplink control signal, which is always transmitted regardless of the data. In this case, speed estimation is difficult because the envelope of the signal is not constant due to power control. There is a problem. Therefore, there is a need for a method for estimating the speed of a terminal in a situation where uplink data is not transmitted.

Accordingly, an object of the present invention is to provide an apparatus and method for estimating the speed of a terminal in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for estimating the speed of a terminal using channel information fed back from the terminal in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for estimating the speed of a terminal using a degree of change of channel information in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for reducing an error when estimating the speed of a terminal using channel information in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for multi-filtering channel information in a wireless communication system and estimating the speed of a terminal using the multi-filtering result.

According to an aspect of the present invention for achieving the above object, in a base station apparatus in a wireless communication system, a detector for detecting channel information fed back from a terminal, and multi-filtering the channel information from the detector with different filter coefficients and And a speed estimating unit estimating a moving speed of the terminal using the multi-filtering result, and a controller performing at least one determination algorithm using the moving speed of the terminal.

According to another aspect of the present invention, in a method of operating a base station in a wireless communication system, detecting channel information fed back from a terminal, multi-filtering the channel information received from the terminal with different filter coefficients, Estimating a moving speed of the terminal using a filtering result, and performing at least one determination algorithm using the moving speed of the terminal.

As described above, since the present invention performs speed estimation using channel information (eg, CQI) transmitted from the terminal to the base station, the speed of the terminal can be estimated without additional overhead. In addition, the speed estimation technique according to the present invention has an advantage of reducing the speed estimation error by using multiple decision metric or crossing threshold values used as comparison values for speed classification. .

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, a method for estimating the speed of a terminal using channel information in a wireless communication system will be described. Here, the channel information is a channel quality indicator (CQI) fed back to the base station from the terminal, the terminal is, for example, carrier to interference and noise ratio (CINR), signal to interference noise ratio (SINR), SNR ( Signal to noise ratio (BER), bit error rate (BER), and round trip delay (RTD) can be measured and fed back to the base station.

Although an OFDM / OFDMA based broadband wireless access system is described below by way of example, the present invention can be easily applied to other wireless communication systems that feed back channel information.

In general, the base station may use channel information fed back from the terminal to the adaptive modulation and coding (AMC) scheme, resource scheduling, handover, and the like. Since the terminal always transmits the CQI to the base station periodically even without the uplink data, the base station may estimate the speed of the terminal using the CQI. However, since the uplink CQI signal is affected by the uplink power control, the present invention proposes a method of estimating the speed using the CQI value instead of the envelope of the uplink CQI signal. That is, the speed of the terminal is estimated using the degree of change of the CQI value.

First, a method of estimating speed by measuring a difference in CQI values between two adjacent frames will be described. As shown in Equation 1, the speed can be determined by averaging the difference in the CQI values for a predetermined period and using the average value as the decision metric.

[Equation 1]

는 하기 <수학식 2와> 같이 IIR(Infinite Impulse Response) 필터링을 이용한 누적 평균기로 구할 수 있다.In the actual implementation, the decision metric of the kth frame

May be obtained as a cumulative average using Infinite Impulse Response (IIR) filtering as shown in Equation 2 below.

[Equation 2]

Here, α is a forgetting factor, and serves to reduce the influence of the rapid change of the metric for a short time period. Such forgetting factor must be properly synchronized with the time variation of the channel to increase the accuracy of the speed estimation. That is, the value of the forgetting element should be appropriately adjusted according to the high speed situation in which the channel changes rapidly and the low speed situation in which the channel changes slowly.

을 구하고, 상기 두 개의 디시전 매트릭들을 미리 설정된 매핑 테이블과 비교하여 속도를 결정할 수 있다.Therefore, the present invention proposes a method of increasing reliability of speed estimation by applying multiple forgetful elements. As an example, the estimation method using two forgetting elements will be described as follows. Two decision matrices by applying a coefficient, i.e. applying multiple oblivion elements

The speed can be determined by comparing the two decision metrics with a preset mapping table.

&Quot; (3) &quot;

Next, a method of estimating a speed by measuring a level crossing rate (LCR) in which a CQI value crosses a specific level while tracking a change in the CQI value will be described. The number of times of satisfying Equation 4 below is counted for a specific level г for a certain period. The counted number LCR may be compared with a preset mapping table to estimate the speed.

&Quot; (4) &quot;

The specific level г may use a predetermined value or may use a CQI average for a predetermined period as shown in Equation 5 below.

[Equation 5]

The present invention proposes a method of increasing reliability of speed estimation by applying multiple forgetful elements to Equation (5). In one embodiment, a method of using two oblivion elements will be described. As shown in Equation 6, by applying a filter coefficient that is easy to distinguish speed at high speed and a filter coefficient that is easy to distinguish speed at low speed, That is, two count values LCR1 and LCR2 may be obtained by applying multiple forgetful elements, and the speed may be determined by comparing the two count values with a preset mapping table.

&Quot; (6) &quot;

Based on the above description will be described a specific embodiment of the present invention.

1 shows a configuration of a receiver in a broadband wireless access system according to an embodiment of the present invention.

As shown, the receiver includes an RF processor 100, an OFDM demodulator 102, a subcarrier demapper 104, an equalizer 106, a demodulator 108, a decoder 110, a channel estimator 112, a CQI. And a demodulator 114 and a speed estimator 116. Hereinafter, it will be assumed that the receiver is a base station.

Referring to FIG. 1, the RF processor 100 first converts a radio frequency (RF) signal received through an antenna into a baseband signal, and converts the baseband signal into digital sample data and outputs the converted digital signal. The OFDM demodulator 102 OFDM demodulates the sample data from the RF processor 100 to generate data in the frequency domain. Here, the OFDM demodulator 102 may generate data in the frequency domain by removing a guard interval (eg, a cyclic prefix) from the received OFDM symbol and performing an inverse fast fourier transform (IFFT) operation. The subcarrier demapper 104 extracts traffic data, pilot data, control data (uplink control channel data), etc., from the data in the frequency domain, and provides each to a corresponding component. For example, the traffic data may be provided to the equalizer 106, the pilot data may be provided to the channel estimator 112, and the uplink CQI channel data may be provided to the CQI demodulator 114.

The CQI demodulator 114 demodulates the CQI channel data to restore the CQI value received from the terminal, and provides the CQI value to the speed estimator 116. The speed estimator 116 estimates the speed of the terminal using a CQI value periodically received from the terminal, and provides the estimated speed to the channel estimator 112. The speed estimator 116 may estimate the speed by the above two methods, and detailed configuration and operation will be described later with reference to FIGS. 2 and 3.

The channel estimator 116 determines a channel estimating technique using a speed estimating result (eg, high speed or low speed) from the speed estimating unit 116, and processes the received pilot data with the determined channel estimating technique to determine a channel coefficient. (Or channel impulse response).

For example, the system may perform channel estimation using an averaging method, an interpolation method, a Wiener filtering method, etc. according to the physical channel type. Here, in the case of a PUSC subchannel rotation disable mode or a channel structure such as a band AMC, since pilot symbols are continuously located along the time axis, channel estimation is performed using all pilot symbols during a period where channel correlation exists. It can improve performance. On the other hand, in the case of the Wiener filtering method, channel estimation performance can be improved by applying different filter coefficients according to the speed of the terminal. For example, the Wiener filter coefficient for the representative speed of each speed section may be calculated and stored in advance, and channel estimation may be performed using the corresponding filter coefficient according to the estimated speed.

FIG. 6 is a diagram illustrating a winner filtering method that may be applied to a PUSC SR disable mode. Assuming that the window size of the filtering is 7 OFDM symbols, the receiver may filter the received pilot symbols while moving the window in a sliding manner to obtain a channel coefficient of each subcarrier. The filter coefficients (W [-2] .W [-1], W [0] .W [1], W [2]) applied at this time may be differently applied depending on the speed, for example, as shown in Table 1 below. Can be. As shown in Table 1 below, for example, when the estimated speed is a low speed, the filter coefficient applied to the Wiener filter is (0.97, 0.99,1.0.0.98.0.97), and Winer is when the estimated speed is a medium speed. The filter coefficient applied to the filter is (0.85, 0.96, 1.0, 0.94, 0.85), and the filter coefficient applied to the Wiener filter at high speed may be (0.7, 0.9. 1.0, 0.85, 0.7).

TABLE 1

Weight factor W [-2] W [-1] W [0] W [1] W [2] Low speed <10km / h 0.97 0.99 1.0 0.98 0.97 10km / h <Medium Speed <30km / h 0.85 0.96 1.0 0.94 0.85 High speed> 30km / h 0.7 0.9 1.0 0.85 0.7

The equalizer 106 uses a channel coefficient (or channel impulse response) from the channel estimator 112 to compensate for the traffic data (burst data) from the subcarrier demapper 104. output by compensation or equalization). That is, the distortions generated in the wireless channel are compensated for and output.

The demodulator 108 demodulates the symbols from the equalizer 106 according to the modulation scheme of the transmitter and outputs encoded data. The decoder 110 decodes the coded data from the demodulator 108 according to the coding method of the transmitter and restores the original information data.

2 shows a configuration of a speed estimator 116 according to an embodiment of the present invention.

As shown, the speed estimator 116 uses the delay 200, the subtractor 202, the absolute value calculator 204, the first filter 206, the second filter 208, and the speed determiner 210. Include.

Referring to FIG. 2, first, the k-th CQI value CQI (k) input from the CQI demodulator 114 is provided to the delay unit 200 and the subtractor 202. The delay unit 200 delays the input CQI value once and provides it to the subtractor 202.

The subtractor 202 is a (k-1) th CQI value CQI (k-1) input from the delayer 200 at a kth CQI value CQI (k) input from the CQI demodulator 114. ) And subtract the output. The absolute value calculator 204 obtains the absolute value of the value from the subtractor 202 and outputs it. That is, the subtractor 202 and the absolute value calculator 204 calculate a difference value between the k th CQI value and the (k-1) th CQI value.

The first filter 206 outputs the value from the absolute value calculator 204 by IIR filtering, for example, as shown in Equation 2 above. In this case, the first filter 206 may perform filtering using filter coefficients (or forgetting elements) that are easily distinguishable at low speed.

The second filter 208 outputs the value from the absolute value calculator 204 by IIR filtering, for example, as shown in Equation 2 above. In this case, the second filter 206 may perform filtering using a filter coefficient (or forgetting element) that is easy to distinguish speed at high speed.

The speed determiner 210 includes a mapping table for determining a speed, and the first decision metric from the first filter 206 and the second decision metric from the second filter 208 are mapped to the mapping table. Compared with, to determine the moving speed of the terminal. The movement speed of the terminal thus determined is provided to the channel estimator 112 and the host controller, and may be used in various decision algorithms.

3 shows a configuration of a speed estimator 116 according to another embodiment of the present invention.

As shown, the speed estimator 116 includes a retarder 300, a first filter 302, a second filter 304, an LCR counter 306, and a speed determiner 308.

Referring to FIG. 3, first, the k-th CQI value CQI (k) input from the CQI demodulator 114 is a delay unit 300, an LCR counter 306, a first filter 302, and a second filter 304. Is provided. The delay unit 300 delays the input CQI value once and provides it to the LCR counter 306.

The first filter 302 outputs the input CQI value by IIR filtering, for example, as shown in Equation 6. In this case, the first filter 302 may perform filtering using a filter coefficient (or forgetting element) that is easily distinguishable at low speed. The second filter 304 IIR-filters and outputs the input CQI value as shown in Equation 6, for example. In this case, the second filter 302 may perform filtering using a filter coefficient (or forgetting element) that is easy to distinguish speed at high speed.

FIG. 7 is a graph comparing the effects of speed classification according to forgetting factor values. FIG. As shown, when the forgetting factor (α: ALPHA) value applied to IIR filtering is 0.9 (upper graph), it is easy to distinguish the speed at low speed, and when the forgetting factor value is 0.1 (lower graph), speed at high speed It can be seen that easy to distinguish. That is, the first filter 302 and the second filter 304 filter the CQI value received from the terminal with different forgetting element values to generate multiple crossing thresholds.

The LCR counter 306 stores the k-th CQI value input from the CQI demodulator 114, the k-1 th CQI value input from the delay unit 300, and the first level from the first ?? In comparison, the first frequency count LCR1 crossing the first reference level is counted. In addition, the LCR counter 306 is a k-th CQI value input from the CQI demodulator 114, a k-1 th CQI value input from the delay unit 300 and the second from the second 304 By comparing two levels, a second frequency count LCR2 intersecting the second reference level is counted.

8 is a graph illustrating variation of CQI values and reference level variation over time. For example, the upper graph of FIG. 8 is a graph based on the first reference level calculated by the first filter 302, and the lower graph of FIG. 8 is a graph based on the second reference level calculated by the second filter 304. Can be. That is, the LCR counter 306 determines and outputs the first reference level crossing frequency LCR1 and the second reference level crossing frequency LCR2 during the setting period based on the graph as shown in FIG. 8. do.

The speed determiner 308 includes a mapping table for speed determination, and compares a plurality of crossing frequencies LCR1 and LCR2 from the LCR counter 306 with the mapping table to determine a moving speed of the terminal. For example, the mapping table may be represented as shown in Table 2 below.

TABLE 2

Alpha = 0.9 Alpha = 0.1 Terminal speed LCR count
(LCR1, LCR2) 31 or less 50 or less Low speed (less than 10km / h) 31 or more, 105 or less 50 or more, 122 or less Medium speed (more than 10km / h, less than 30km / h) 31 and above, 82 and below 40 or more, 122 or less 82 or more High speed (more than 30km / h)

Referring to Table 2, for example, the frequency LCR1 crossing the first reference level is present between 31 and 82 during the setting period, and the frequency LCR2 crossing the second reference level during the setting period is shown. If present between 40 and 122, the terminal speed may be determined at medium speed. At this time, the reference values for distinguishing the speed section shown in Table 2 are just one example, it is preferable to optimize through experimentation in actual operation.

4 illustrates an operation procedure of a base station in a wireless communication system according to an embodiment of the present invention. In particular, FIG. 4 is a method of estimating speed by measuring a difference in CQI values between two adjacent frames.

Referring to FIG. 4, the base station first checks whether a CQI value is received from the terminal in step 401. When the CQI value is received, the base station obtains a difference between the currently received CQI value and the previously received CQI value in step 403, multi-IIR filters the difference value using multiple filter coefficients, and then selects a plurality of decision metrics. Calculate For example, a first decision metric is obtained by IIR filtering with a first filter coefficient that is easy to distinguish speed at low speed, and a second decision metric is obtained by IIR filtering with a second filter coefficient that is easy to distinguish speed at high speed. You can get it.

In step 405, the base station compares the plurality of decision metrics with a mapping table for speed classification to determine a moving speed of the terminal. The movement speed of the terminal thus determined may be used for channel estimation.

When used for the channel estimation, the base station selects a channel estimation filter coefficient suitable for the movement speed of the terminal in step 407. For example, as shown in Table 1, the base station includes a filter coefficient according to each speed section as a table, and compares the determined moving speed with the table to apply a filter coefficient to a channel estimation filter (e.g., Wiener filter). Can be determined.

In step 409, the base station sets the determined filter coefficient to the channel estimation filter and filters the received pilot symbols using the channel estimation filter to determine a channel coefficient (or channel impulse response) of each subcarrier.

Thereafter, the base station processes the received traffic using the determined channel coefficient in step 411. For example, the base station may perform channel compensation on the received traffic data using the channel coefficient, and demodulate and decode the channel compensated data to restore original information data.

5 is a flowchart illustrating an operation procedure of a base station in a wireless communication system according to an embodiment of the present invention. In particular, FIG. 5 illustrates a method of estimating speed by measuring a frequency crossing rate (LCR) in which a CQI value crosses a specific level.

Referring to FIG. 5, the base station first checks whether a CQI value is received from the terminal in step 501. When the CQI value is received, the base station performs multiple IIR filtering on the received CQI value using multiple filter coefficients in step 503 to determine a plurality of reference levels. For example, a first reference level may be obtained by IIR filtering with a first filter coefficient that is easily distinguishable at low speed, and a second reference level may be obtained by IIR filtering with a second filter coefficient that is easily distinguishable at high speed. have.

In step 505, the base station determines a first frequency LCR1 at which a CQI value periodically received is intersected with the first reference level, based on the first reference level during the set period. The CQI value periodically received based on the second reference level determines the second frequency LCR2 intersecting the second reference level.

As described above, after determining the plurality of frequencies LCR1 and LCR2 by multiple filtering, the base station compares the plurality of frequencies with a mapping table for speed classification in operation 507 to determine the moving speed of the terminal. The movement speed of the terminal thus determined may be used for channel estimation.

After determining the movement speed of the terminal, the base station selects a channel estimation filter coefficient suitable for the movement speed of the terminal in step 509. For example, as shown in Table 1, the base station includes a filter coefficient according to each speed section as a table, and compares the determined speed with the table to apply to a channel estimation filter (for example, a Wiener filter). Can be determined.

In step 511, the base station sets the selected filter coefficient to the channel estimation filter and filters the received pilot symbols using the channel estimation filter to determine a channel coefficient (or channel impulse response) of each subcarrier.

In step 513, the base station processes the received traffic using the determined channel coefficient. For example, the base station may perform channel compensation on the received traffic data using the channel coefficient, and demodulate and decode the channel compensated data to restore original information data.

In the above-described embodiment of the present invention, a method of estimating a moving speed of a terminal and using the estimated speed for channel estimation has been described. However, the estimated moving speed of the terminal is not only channel estimation but also various determination algorithms such as transmission technique (coding, modulation, multiple antenna technique, etc.) determination, resource scheduling, handover determination, ranging period determination, power control technique determination, etc. It can be used to. For example, the power control technique (closed loop power control, open loop power control, etc.) may be switched according to the moving speed of the terminal. In another example, the period of periodic ranging may be changed according to the moving speed of the terminal.

On the other hand, the embodiment of the present invention, it is described that the downlink channel value (CQI) measured by the terminal to the base station, the base station to estimate the speed of the terminal using the channel value. In another embodiment, the terminal may estimate the moving speed using the downlink channel value, and report the estimated moving speed to the base station.

In the detailed description of the present invention, specific embodiments have been described, but various modifications may be made 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.

1 is a diagram showing the configuration of a receiver in a broadband wireless access system according to an embodiment of the present invention.

2 is a diagram showing a detailed configuration of a speed estimator according to an embodiment of the present invention.

3 is a diagram showing a detailed configuration of a speed estimator according to another embodiment of the present invention.

4 is a diagram illustrating an operation procedure of a base station in a wireless communication system according to an embodiment of the present invention.

5 is a diagram illustrating an operation procedure of a base station in a wireless communication system according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating a winner filtering method that may be applied to a PUSC SR disable mode. FIG.

Figure 7 is a graph comparing the effect of the speed classification according to the forget element value.

8 is a graph showing variation in CQI values and reference levels over time.

Claims (19)

A base station apparatus in a wireless communication system, A detector for detecting channel information fed back from the terminal; A speed estimator configured to multi-filter channel information from the detector with different filter coefficients, and to estimate a moving speed of the terminal using the multi-filtering result; And a controller for performing at least one determination algorithm using the moving speed of the terminal. The method of claim 1, And the channel information is a downlink channel measurement value. The method of claim 1, wherein the speed estimating unit, A calculator for calculating a difference between the received channel information value and the previously received channel information value; Multiple IIR filtering the difference using different filter coefficients to generate multiple decision metrics; And a speed determiner configured to determine the moving speed of the terminal by comparing the multiple decision metrics with a speed mapping table. The method of claim 3, The different filter coefficients may include at least one of a first filter coefficient for low speed, a second filter coefficient for medium speed, and a third filter coefficient for high speed. The method of claim 1, wherein the speed estimation unit, Multiple IIR filtering the received channel information values using different filter coefficients to generate a plurality of reference levels; A counter for counting a frequency at which each of the plurality of reference levels and a channel information value intersect for a set period; And a speed determiner configured to determine the moving speed of the terminal by comparing the counted plurality of frequencies with a speed mapping table. The method of claim 5, The different filter coefficients may include at least one of a first filter coefficient for low speed, a second filter coefficient for medium speed, and a third filter coefficient for high speed. The method of claim 1, And the at least one determination algorithm comprises at least one of channel estimation technique determination, multiple antenna technique determination, transmission technique determination, handover determination, ranging period determination, and power control technique determination. The method of claim 1, And a channel estimator for determining a channel estimation filter coefficient suitable for the moving speed of the terminal and estimating a channel coefficient by filtering the received pilot symbols with the determined filter coefficient. The method of claim 8, A channel compensator for channel compensating the received traffic data using a channel coefficient from the channel estimator; A demodulator for demodulating the channel compensated data; And a decoder for decoding the demodulated data. The method of claim 1, The speed estimating apparatus includes a speed mapping table for mapping a speed and at least two values obtained through the multiple filtering. In the method of operation of a base station in a wireless communication system, Detecting channel information fed back from the terminal; Multi-filtering channel information received from the terminal with different filter coefficients, and estimating a moving speed of the terminal using the multiple filtering results; And performing at least one determination algorithm using the moving speed of the terminal. The method of claim 11, The channel information is a downlink channel measurement value. The method of claim 11, wherein the estimating process of the terminal comprises: Calculating a difference between the received channel information value and the previously received channel information value, Generating multiple decision metrics by performing multiple IIR filtering on the difference using different filter coefficients; And comparing the multiple decision metric with a speed mapping table to determine a moving speed of the terminal. The method of claim 13, The different filter coefficients may include at least one of a first filter coefficient for low speed, a second filter coefficient for medium speed, and a third filter coefficient for high speed. The method of claim 11, wherein the estimating process of the terminal comprises: Generating a plurality of reference levels by multiple IIR filtering the received channel information values using different filter coefficients; Counting a frequency at which each of the plurality of reference levels and a channel information value intersect for a set period; And comparing the counted plurality of frequencies with a speed mapping table to determine a moving speed of the terminal. The method of claim 15, The different filter coefficients may include at least one of a first filter coefficient for low speed, a second filter coefficient for medium speed, and a third filter coefficient for high speed. The method of claim 11, The at least one determination algorithm includes at least one of channel estimation technique determination, multiple antenna technique determination, transmission technique determination, handover determination, ranging period determination, and power control technique determination. The method of claim 11, Determining a channel estimation filter coefficient suitable for the moving speed of the terminal; And estimating a channel coefficient by filtering the received pilot symbols with the determined filter coefficients. The method of claim 18, Channel-compensating the received traffic data using the channel coefficient; Demodulating the channel compensated data; And decoding the demodulated data.

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