KR101541813B1 - Cinr estimation apparatus and method in a wireless communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for estimating CINR (Carrier to Interference and Noise Ratio) in a wireless communication system, and more particularly, to a CINR measurement unit for measuring a CINR value from a received signal, a CINR A filter type determination unit for determining a type of a filter according to a result value output from the CINR comparison unit; a filter coefficient determination unit for determining a filter coefficient; and an output unit for outputting the determined CINR value, By selecting a filter type and a filter coefficient according to a channel environment change, it is possible to maximize utilization of the entire system operation resource by estimating and reflecting the CINR actively and adaptively, thereby improving service quality .

Carrier to Interference and Noise Ratio (CINR), a filter,

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a CINR ESTIMATION APPARATUS AND METHOD IN A WIRELESS COMMUNICATION SYSTEM,

The present invention relates to an apparatus and method for estimating a CINR (Carrier to Interference and Noise Ratio) in a wireless communication system, and more particularly, And an apparatus and method for estimating the CINR.

2. Description of the Related Art Generally, a wireless communication system is a system developed by a terminal to transmit a wireless signal to perform communication regardless of a location. In the wireless communication system, the receiver increases the throughput of the system and grasps the state of the channel for seamless handover.

The receiver estimates the Carrier to Interference and Noise Ratio (CINR) of a specific signal transmitted from the transmitter, and transmits the CINR to the receiver through a feedback channel Thereby informing the transmitter of the channel status. Also, the transmitter may determine a data rate using information received through the feedback channel. In addition to the rate determination, information received via the feedback channel is used in a wide variety of applications. An example of a CINR measurement method in the wireless communication system is as follows.

1 is a block diagram for generally measuring a CINR in an orthogonal frequency division multiple access (OFDM) wireless communication system, which is an example of a wireless communication system.

1, a receiver converts a signal received through an antenna 101 to a baseband signal through a RF (Radio Frequency) unit 103 and transmits the baseband signal through an ADC (Analog Digital Converter) 105 And the received signal is filtered by the reception filter 107. Then, the receiver removes the CP from the filtered signal through a CP (Cyclic Prefix) eliminator and a deserializer 109, converts the CP into an analog signal in parallel, and then, in a fast Fourier transform (FFT) Area signal. Thereafter, the receiver combines the PN code assigned to each user and the converted signal in the PN code generator 115 in the signal synthesizer 113 to extract only the received signal from the PN synthesizer 113, and outputs the combined signal to the CINR estimator 117 And separates the interference and noise components from the extracted signal to estimate the ratio of the received signal to the interference and noise components.

As described above, when the CINR measured at the receiving end, that is, the terminal or the base station is used as it is, sudden fluctuations are reflected in the whole system operation as it is when the CINR fluctuates rapidly, thus ensuring accurate and stable system operation and the best performance I can not receive it. Alternatively, when the CINR is used through a certain filter, the change of the radio channel environment can not be accurately reflected in the system at the proper time, so that the best performance can not be guaranteed in the entire system operation. For example, in an environment where the channel environment is rapidly deteriorated, a CINR change can be rapidly tracked and reflected in a system operation so that a modulation and coding method suitable for the environment can be selected. In addition, scheduling is possible. However, when the fast CINR change is not applied, an appropriate modulation and coding method selection is not performed. Therefore, an error occurs in a packet received from a terminal or a base station, and a proper scheduling is not performed in the base station, Waste can occur. On the other hand, when the wireless channel environment rapidly improves, proper CINR reporting can be performed to select and schedule modulation and coding methods that maximize system performance. Therefore, there is a need for an alternative to select a filter and a coefficient suitable for CINR calculation according to the channel change situation.

Accordingly, it is an object of the present invention to provide an apparatus and method for calculating a more accurate CINR (Carrier to Interference and Noise Ratio) in a wireless communication system.

According to an aspect of the present invention, there is provided a method of measuring a signal-to-interference-and-noise ratio (CINR) of a mobile communication system, Comparing the measured signal-to-noise ratio with a reference value, determining a filter according to the comparison result, and calculating a signal-to-noise ratio using the determined filter.

According to a second aspect of the present invention, there is provided an apparatus for measuring a signal-to-interference noise ratio (SNR) in a mobile communication system, the apparatus comprising: an apparatus for measuring a signal-to-noise ratio of a received signal; A device for making a comparison, a device for determining a filter according to the compared result, and a device for calculating a signal-to-noise ratio using the determined filter.

According to a third aspect of the present invention, there is provided a method of measuring CINR in a mobile communication system, comprising: measuring a CINR_Org using a received signal; comparing CINR_Org and CINR_Linear, which is a calculated CINR; Determining at least one of a filter type and a filter coefficient according to a comparison result of the CINR_Org and the CINR_Linear; inputting the CINR_Org and the CINR_Linear to a filter determined according to the filter type and the filter coefficient, And updating the data.

The present invention relates to a method and apparatus for estimating and reflecting Carrier to Interference and Noise Ratio (CINR) actively and adaptively by selecting a filter type and a filter coefficient according to a change of a wireless channel environment in a wireless communication system, So that the service quality can be improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, the present invention will be described in terms of a CINR estimation algorithm adaptive to a change in channel conditions in a wireless communication system.

FIG. 2 shows a block configuration of an apparatus for estimating a CINR using a filter type and a method for determining a filter coefficient according to a preferred embodiment of the present invention. In the following description, the apparatus for estimating the CINR is referred to as a " CINR predictor ".

2, the CINR estimator includes a CINR measurement unit 202, a CINR comparison unit 204, a filter type determination unit 206, a filter coefficient determination unit 208, and a CINR output unit 210 .

The CINR measuring unit 202 measures the CINR of the received signal. The CINR comparator 204 compares the CINR measured from the received signal with the CINR calculated according to the present invention. The filter type determination unit 206 determines a filter type according to a result of the CINR comparison unit 204. [ The filter coefficient determination unit 208 determines a filter coefficient by an algorithm that predicts a channel state change direction. The CINR output unit 210 calculates and outputs a CINR through a filter determined according to a value determined by the filter type determination unit 206 and the filter coefficient determination unit 208. For example, the CINR output unit 210 calculates a CINR according to Equation (1).

if (CINR_Linear <CINR_Org) {

   Step ++;

   If (Step> Step_th)

     CINR_Linear = CINR_Linear * (1.-α_1) + α_1 * CINR_Org;

   Else

     CINR_Linear = CINR_Linear * (1.-α_2) + α_2 * CINR_Org;

  }

else {

   Step = 0;

   CINR_Linear = CINR_Linear * (1.-β) + β * CINR_Org;

  }

In Equation (1), the CINR_Org is the measured CINR and the CINR_Linear is the processed signal-to-noise ratio, that is, the CINR passed through the filter, and the Step is the number of times the measured CINR is higher than the processed CINR Wherein Step_th is a threshold used for selecting a filter coefficient by using a direction of a wireless channel state change, and α_1, α_2, and β are used for predicting a change direction of a wireless channel state Represents the filter coefficient value to be applied.

FIG. 3 illustrates a procedure for estimating a CINR according to a channel environment in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 3, the CINR estimator measures a received CINR in step 301. FIG. Herein, the received CINR means an actual CINR measured from a received signal. That is, the CINR estimator separates interference and noise components from a received signal, and calculates a ratio between a signal to be received and the interference and noise components. For example, the CINR estimator separates the interference and the noise component using a finite impulse response (FIR) filter having band pass or high pass characteristics.

After measuring the reception CINR, the CINR estimator proceeds to step 303 and compares the reception CINR and the current CINR calculation value. That is, since the CINR estimator continuously repeats the procedure, the calculated CINR value is maintained. The CINR estimator uses the current CINR calculation value for the next CINR calculation value. Accordingly, the CINR estimator compares the received CINR and the calculated CINR.

If the received CINR is less than or equal to the CINR calculated value, the CINR estimator proceeds to step 305 to initialize the step variable, i.e., to 0, to determine the filter type to be B and the filter coefficient to be β. Then, the CINR estimator proceeds to step 315.

On the other hand, if the received CINR is greater than the CINR calculated value, the CINR estimator proceeds to step 307 to increment the Step variable by 1 and determine the filter type as A. After determining the filter type as A, the CINR estimator proceeds to step 309 and checks whether the value of the Step variable is greater than Step_Th. Here, Step_Th denotes a threshold to be used for selecting a filter coefficient using the direction of the wireless channel state change.

If the value of the Step variable is greater than the Step_Th, the CINR estimator proceeds to step 311 and determines the filter coefficient as? _2. On the other hand, if the value of the Step variable is less than or equal to the Step_Th, the CINR estimator proceeds to step 313 and determines the filter coefficient as α_1. That is, through steps 309 to 313, the CINR estimator determines the filter coefficient according to the number of consecutive occurrences of the comparison result that the reception CINR is greater than the CINR calculation value.

After determining the filter coefficient, the CINR estimator proceeds to step 315 and determines a filter for CINR calculation. At this time, the filter is determined according to the filter type and the filter coefficient. For example, the filter has the form of a cumulative averaging function with the filter coefficient as a fogotten factor.

After determining the filter, the CINR estimator proceeds to step 317 and filters the received CINR. That is, the CINR estimator obtains a new CINR calculation value by inputting the reception CINR to the filter determined in step 315. [ In other words, the CINR estimator updates the CINR calculation value by inputting the reception CINR and the CINR calculation value to a filter determined according to the filter type and the filter coefficient.

In step 319, the CINR estimator outputs the calculated CINR.

FIG. 4 is a simulation result of a signal-to-noise ratio characteristic according to the application of the present invention, and shows characteristics of CINR when the present invention is applied and when the present invention is not applied.

Referring to FIG. 4, the 'actual measurement value' represents the actually measured CINR variation, and 'when applying the present invention' is a case according to the present invention, in which the filter coefficient And the CINR changes when the CINR is adjusted. That is, as shown in FIG. 4, the rate of change of the CINR calculation value can be adjusted by adjusting the filter coefficient.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a block diagram for measuring a signal-to-interference noise ratio in a wireless communication system,

FIG. 2 is a block diagram for estimating a signal-to-interference noise ratio using a method of determining a filter type and a filter coefficient according to a preferred embodiment of the present invention;

Figure 3 is a flow chart for the practice of the present invention,

4 is a simulation result of a signal-to-noise ratio characteristic according to the application of the present invention.

Claims (7)

A method for measuring a signal-to-interference and noise ratio (CINR) of a mobile communication system, Measuring a signal-to-noise ratio of a received signal; Comparing the measured signal-to-noise ratio with a reference value; Determining at least one of a filter type and a filter coefficient based on the comparison result; And calculating a signal-to-noise ratio using a filter determined based on at least one of the filter type and the filter coefficient. The method according to claim 1, The reference value, The measured signal-to-noise ratio, the number of times that the measured signal-to-noise ratio is higher than the reference value according to the comparison, the threshold value to be used for selecting the filter coefficient using the wireless channel state change direction, &Lt; / RTI &gt; is determined based on the filter coefficient values to be applied according to &lt; RTI ID = 0.0 &gt; The method according to claim 1, The filter includes: A threshold value to be used for selecting a filter coefficient based on the measured signal-to-noise ratio, the reference value, the number of times that the measured signal-to-noise ratio is higher than the reference value, Is determined based on the filter coefficient values to be applied according to the radio channel conditions. An apparatus for measuring a signal-to-interference and noise ratio (CINR) in a mobile communication system, An apparatus for measuring a signal-to-noise ratio of a received signal, An apparatus for comparing the measured signal-to-noise ratio with a reference value, An apparatus for determining at least one of a filter type and a filter coefficient based on the comparison result; An apparatus for calculating a signal-to-noise ratio using a filter determined based on at least one of the filter type, the filter type and the filter coefficient. A method for measuring Carrier to Interference and Noise Ratio (CINR) in a mobile communication system, Measuring CINR_Org using a received signal; Comparing the CINR_Org and the calculated CINR, CINR_Linear, Determining at least one of a filter type and a filter coefficient based on a comparison result of the CINR_Org and the CINR_Linear; And updating the CINR_Linear by inputting the CINR_Org and the CINR_Linear to a filter determined based on at least one of the filter type and the filter coefficient. 6. The method of claim 5, Further comprising the step of determining the filter coefficient according to the number of consecutive occurrences of the comparison result that the CINR_Org is greater than the CINR_Linear. The method according to claim 6, Wherein the filter has the form of a cumulative mean function with the filter coefficient as a fogotten factor.

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