KR20120070811A - Decoder and method for detecting error data thereof - Google Patents

Abstract

PURPOSE: A decoder and a method for eliminating error data are provided to ensure system stability by preventing performance degradation caused by error data. CONSTITUTION: A candidate data extracting unit(110) receives data demodulated through a demodulator. A de-rate matching unit(120) performs de-rate matching for candidate data. A channel decoding unit(130) performs channel decoding for de-rate matched data. A state matching determining unit(140) compares an initial state metric with a final state metric in survivor path information. A reference accumulation path determining unit(150) determines the survivor path information to satisfy a reference accumulation path value. A cyclic redundancy checking unit(160) performs cyclic redundancy check for inputted candidate data. An accumulation path queue determining unit(170) aligns all down link control information data determined as valid data through the cyclic redundancy check based on the survivor path information.

Description

Decoder and how to remove error data from decoder {DECODER AND METHOD FOR DETECTING ERROR DATA THEREOF}

TECHNICAL FIELD The present invention relates to a receiver decoder of a communication system, and more particularly, to a decoder for detecting data in which an error occurs and a method for detecting error data thereof.

A physical downlink control channel (PDCCH), which is a channel for transmitting control information on transmission data in a communication system, is used. The physical downlink control channel transmits and receives control data through various downlink control information (DCI) formats. For example, a base station of a communication system transmits downlink resource allocation information, information on a hybrid automatic repeat reQuest (HARQ) procedure, information on a modulation and coding scheme of a transmission signal to a terminal through a physical downlink control channel. Can transmit In addition, the base station transmits uplink resource block allocation information and uplink scheduling grant information to the terminal through a downlink control information format through a physical downlink control channel.

Therefore, the terminal should accurately detect data received through the physical downlink control channel. However, the terminal receiving data through the physical downlink control channel does not know exactly the type of the terminal's own control information and the location of the control information on the physical downlink control channel. Since the UE does not know the location of the control information and the control information, the terminal performs blind detection on the physical downlink control channel. Through blind detection, the terminal decodes data of a physical downlink control channel. Here, the decoded data is determined as an example, whether the data is valid through a cyclic redundancy check (CRC).

의 확률로 순환 중복 검사 오류가 발생할 수 있다. 물리 하향링크 제어 채널에서 단말은 1 밀리초(ms) 동안 48회 이상의 블라인드 디코딩을 수행한다. 즉, 약 1.4초 동안 단말은 674200회의 블라인드 디코딩을 수행함에 따라 16비트 패리티의 순환 중복 검사 오류가 1번 발생한다. 따라서, 물리 하향링크 데이터 제어 채널을 통한 단말의 블라인드 디코딩 동작 횟수의 증가는 오류가 발생된 데이터가 증가하게 된다. 단말에서, 순환 중복 검사를 통해 물리 하향링크 제어 채널의 데이터 오류를 검출하더라도 디코딩에 따른 오류 발생 데이터가 여전히 존재한다는 문제점이 있었다.In cyclic redundancy check, for example, using 16 bits of parity,

A probability of cyclic redundancy check can occur. In the physical downlink control channel, the UE performs 48 or more blind decodings for 1 millisecond (ms). That is, as the UE performs 674200 blind decoding for about 1.4 seconds, a cyclic redundancy check error of 16-bit parity occurs once. Therefore, an increase in the number of blind decoding operations of the terminal through the physical downlink data control channel causes an error in data. In the terminal, even if a data error of a physical downlink control channel is detected through cyclic redundancy check, there is a problem that error occurrence data according to decoding still exists.

An object of the present invention is to provide a decoder for detecting error data generated in a decoding operation and a method for detecting error data thereof.

Another object of the present invention is to provide a decoder for detecting error data according to decoding of a physical downlink control channel and a method of detecting error data thereof.

Another object of the present invention is to provide a decoder for detecting error data generated by blind decoding and a method of detecting error data thereof.

The decoder of the present invention includes a candidate data extraction unit for extracting candidate data from demodulated data, a derate matching unit for derate matching the extracted candidate data, a channel decoding unit for performing channel decoding on the derate matched data, A cyclic redundancy check unit configured to cyclically check the channel decoded candidate data to determine validity of the data, and a predetermined number of downlink control channel data having the validity determined in the order of decreasing errors according to the cumulative path value of the channel decoding It includes a cumulative path alignment determination unit for outputting downlink control channel data of the.

In this embodiment, the channel decoding unit performs at least one of a Viterbi decoding operation and a tail biting Viterbi decoding operation.

In this embodiment, located between the channel decoding unit and the cyclic redundancy check unit, receives the survival path information through the channel decoding, and removes the error data by comparing the state of the initial metric and the last metric of the survival path information It further comprises a state matching determination unit.

In this embodiment, if the state of the initial metric and the last metric of the survival path information does not match, it is determined as the error data.

In this embodiment, a reference cumulative path determining unit, which is located between the channel decoding unit and the cyclic redundancy check unit, removes error data by determining whether a cumulative path value satisfies a reference cumulative path value from the survival path information. Include.

In this exemplary embodiment, the reference cumulative path determining unit may include: a gain setting unit configured to set a plurality of gain values according to sizes of a physical downlink control channel format and a control data channel format; A reference value setting unit for generating a plurality of reference cumulative path values through a calculation, a selection unit for selecting a reference cumulative path value corresponding to the gain value among the plurality of reference cumulative path values, and the cumulative path value and the reference cumulative value It includes a comparison unit for removing the error data by comparing the values.

In this embodiment, the gain setting unit sets the gain value based on radio channel environment information.

In this embodiment, the cumulative path alignment determination unit may include: a path value matching unit for matching data channel information data determined as valid data through the cyclic redundancy check with valid information values of a survival path through the channel decoding; And a data alignment unit for sorting the valid data in the order of less errors based on the accumulated path values through the path value matching, and selecting and outputting a predetermined number of valid data in the sorted order.

In this embodiment, the demodulation data is data obtained by demodulating data received through a physical downlink control channel.

In the decoder of the present invention, a method of removing error data may include extracting candidate data from demodulated data, performing derate matching on the extracted candidate data, performing channel decoding on the derate matched data, and decoding the channel. Determining the validity of the data by performing cyclic redundancy check of the candidate data; and determining a predetermined number of downlink control channels in order of decreasing errors according to the cumulative path value of the channel decoding. Outputting the data.

In this embodiment, the channel decoding is at least one of Viterbi decoding and tail biting Viterbi decoding.

In this embodiment, after the step of performing the channel decoding, receiving the survival path information through the channel decoding, and removing the error data by comparing the state of the initial metric and the last metric of the survival path information It includes more.

In this embodiment, removing the error data through the state comparison includes determining the error data if the state of the initial metric and the last metric of the survival path information does not match.

In this embodiment, after performing the channel decoding, the method may further include removing error data from the survival path information by determining whether a cumulative path value satisfies a reference cumulative path value.

In this embodiment, removing the error data by determining whether the cumulative path value satisfies the reference cumulative path value may include setting a plurality of gain values according to sizes of a physical downlink control channel format and a control data channel format. Generating a plurality of reference cumulative path values through operation of the plurality of gain values and a preset reference value, and selecting a reference cumulative path value corresponding to the gain value from the plurality of reference cumulative path values And removing the error data by comparing the cumulative path value with the reference cumulative value.

In this embodiment, setting the gain value further includes setting the gain value based on radio channel environment information.

The outputting of the downlink control channel data may include matching data channel information data determined as valid data through the cyclic redundancy check with valid information values of a survival path through the channel decoding. And sorting the valid data in the order of less error based on the accumulated path values through the path value matching, and selecting and outputting a predetermined number of valid data in the sorted order.

In this embodiment, the demodulation data is data obtained by demodulating data received through a physical downlink control channel.

According to the present invention, the terminal may detect data errors that were not detected through cyclic redundancy check by detecting the error occurrence data through the detection of the survival accumulated valid data during the decoding operation of the downlink physical control channel. In addition, the terminal can prevent performance degradation due to error occurrence data, and can ensure system stability.

1 illustrates a communication system according to an embodiment of the present invention;
2 illustrates a decoder structure according to an embodiment of the present invention;
3 is a diagram illustrating a structure of a reference cumulative path determining unit according to an exemplary embodiment of the present invention;
4 is a diagram illustrating a structure of a cumulative path alignment determining unit according to an embodiment of the present invention; and
5 is a diagram illustrating a decoding operation of a decoder according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish it, will be described with reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. The embodiments are provided so that those skilled in the art can easily carry out the technical idea of the present invention to those skilled in the art.

In the drawings, embodiments of the present invention are not limited to the specific forms shown and are exaggerated for clarity. In addition, parts denoted by the same reference numerals throughout the specification represent the same components.

The expression "and / or" is used herein to mean including at least one of the components listed before and after. In addition, the expression “connected / combined” is used in the sense including including directly connected to or indirectly connected to other components. In this specification, the singular forms also include the plural unless specifically stated otherwise in the phrases. Also, as used herein, components, steps, operations, and elements referred to as "comprising" or "comprising" refer to the presence or addition of one or more other components, steps, operations, elements, and devices.

The present invention proposes a decoder capable of detecting a data error in a communication system. The communication system of the present invention may be, for example, a Long Term Evolution (LTE) system, which is a next generation mobile communication system proposed by the 3rd Generation Partnership Project (3GPP), an asynchronous cellular mobile communication standard organization. However, the present invention can also be applied to other communication systems that use a decoder to detect error data.

1 is a diagram illustrating a communication system according to an embodiment of the present invention.

Referring to FIG. 1, the communication system includes a base station 10 and a terminal 20.

The base station 10 provides a communication service to the terminal 20 and is connected to a network.

The base station 10 uses a control channel, for example, a physical downlink control channel (PDCCH) to transmit control information for transmission data. Downlink resource allocation information, information on a hybrid automatic repeat reQuest (HARQ) procedure, information on modulation and a coding scheme of a transmission signal may be transmitted to the terminal 20 through a physical downlink control channel. In addition, the base station 10 transmits uplink resource block allocation information and uplink scheduling grant information to the terminal 20 through a downlink control information format through a physical downlink control channel.

The base station 10 encodes the data for transmitting data on the physical downlink control channel.

The base station 10 adds parity bits (for example, 16 bits) to the source data of the physical downlink control channel and uses a convolutional code (for example, tail-biting convolutional coding). Perform the encoding.

The base station 10 performs subblock interleaving which rearranges the sequence of channel coded data bit streams into a predetermined pattern. Here, subblock interleaving distributes the error data in order to prevent a group error of the data. The base station 10 may perform repetition or rate matching of sub-block interleaved data.

The base station 10 modulates the repetitive or rate matched data by using a preset modulation scheme (eg, quadrature phase shift keying (QPSK)) and transmits the data to the terminal 20.

The terminal 20 is connected to the base station 10 to receive a data communication service.

The terminal 20 demodulates using a demodulation scheme corresponding to the modulation scheme of the base station 10. The terminal 20 extracts candidate data according to a data format of a physical downlink control channel, and performs derate matching and deinterleaving on the extracted candidate data. Deinterleaving is an operation of rearranging the order of the bit strings arranged in the base station to the original order.

The terminal 20 performs the Viterbi decoding (eg, tail biting Viterbi decoding) on the deinterleaved bit string, and performs a data error through the Cyclic Redundancy Check (CRC) of the Viterbi decoded bit string. By determining the validity of the decoded data is determined.

In addition, the terminal 20 of the present invention may detect data errors that are not detected in the cyclic redundancy check.

To this end, the terminal 20 selects valid candidate data (ie, candidate data containing less error data) by comparing survival cumulative path values of data determined as valid data as a result of the cyclic redundancy check. Although the accumulated value of the survival path varies depending on the path using the tail biting decoder, the terminal 20 may remove the error data using the survival path accumulated path value. In addition, the terminal 20 removes the error data by determining whether the data is valid using the state metric value of the tail biting Viterbi decoder.

Therefore, the terminal 20 of the present invention can remove error data not detected through the cyclic redundancy check data by removing error data using the tail biting Viterbi decoder characteristic.

Therefore, the terminal 20 of the present invention can prevent a decrease in reception performance due to error data, and can ensure system stability.

2 is a diagram illustrating a decoder structure according to an embodiment of the present invention.

Referring to FIG. 2, the decoder 100 may include a candidate data extractor 110, a derate matcher 120, a channel decoder 130, a state match determiner 140, and a reference cumulative path determiner 150. , A cyclic redundancy check unit 160, and a cumulative path alignment determiner 170. Here, the decoder 100 may be included in the terminal 20.

The candidate data extractor 110 receives demodulated data demodulated by a demodulator (not shown). The demodulation data may be demodulation data for data received through a physical downlink control channel. The candidate data extractor 110 extracts candidate data from demodulated data. The candidate data extractor 110 may extract candidate data for decoding according to a search region and a physical downlink control channel (PDCCH) format. Here, the PDCCH channel format may be, for example, a first PDCCH format (one control channel element (1CCE) having a length of 72 bits), a second PDCCH format (2CCE, having a length of 144 bits), 3 PDCCH format (4CCE, having a length of 288 bits), a fourth PDCCH format (8CCE, having a length of 576 bits).

For example, the candidate data extractor 110 may extract six first PDCCHs (1CCE), six second PDCCHs (2CCE), two third PDCCHs (4CCE), and two fourth PDCCHs (4CCE). Can be.

The decoder 100 may repeat the decoding operation by the number of detectable downlink control information formats.

In this case, the number of times of detectable downlink control information (DCI) formats is decoded, for example, a blind decoding operation is performed so that the total number of physical downlink control channel decoding times is "16 * DCI format number". Since the number of DCI formats is generally three, a total of 48 times are performed in one millisecond (ms) subframe.

The candidate data extractor 110 outputs the extracted candidate data to the derate matcher 120.

The derate matching unit 120 performs derate matching on the candidate data. For derate matching, the derate matching unit 120 reversely performs an operation corresponding to a repetitive operation or a data removal operation (pruning) performed by the base station 10 as a transmitting end. Also, the derate matching unit 120 may deinterleave the derate matched candidate data. The derate matching unit 120 performs deinterleaving, that is, subblock deinterleaving. Meanwhile, the deinterleaving operation of the derate matching unit 120 may be performed through a separate deinterleaver. In this case, the derate matching unit 120 may receive parameters for derate matching and deinterleaving from a module of an upper layer inside the terminal 20.

The derate matching unit 120 outputs the derate matching candidate data to the channel decoding unit 130.

The channel decoding unit 130 performs channel decoding on the derate matching data. For example, the channel decoder 130 may be a tail biting Viterbi decoder. That is, the channel decoding unit 130 extends the length of the derate matched data by 2 or 3 times and then performs tail biting bidderby decoding. The channel decoding unit 130 outputs the survival path information selected through the tail biting Viterbi decoding operation to the state matching determination unit 140, the reference accumulation path determination unit 150, and the accumulation path alignment determination unit 170. . In addition, the channel decoding unit 130 outputs the derate matched candidate data to the state matching determination unit 140.

Meanwhile, the channel decoding unit 130 may be a Viterbi decoder. That is, the channel decoding unit 130 performs Viterbi decoding on the derate matched data. The channel decoder 130 outputs the selected survival path information (eg, minimum distance information) to the reference cumulative path determiner 150 and the cumulative path alignment determiner 170 through a Viterbi decoding operation. If the channel decoding unit 130 is a Viterbi decoder, the state matching determination unit 140 may not exist.

Therefore, the channel decoding unit 130 may be configured as one of a Viterbi decoder and a tail biting Viterbi decoder.

The state match determination unit 140 compares the initial state metric and the last state metric of the survival path information (eg, the state metric). As a result of the comparison, if the values of the initial state metric and the last state metric are equal to each other, the state coincidence determination unit 140 determines valid data. However, if the value of the initial state metric and the last state metric are not equal to each other as a result of the comparison, it is determined as error data. The state coincidence determination unit 140 controls not to perform the cyclic redundancy check operation of the cyclic redundancy check unit 160 on the data determined as the error data. That is, the state coincidence determination unit 140 removes candidate data determined as error data from the derate matching process. The state coincidence determination unit 140 outputs the candidate data from which the error data is removed to the reference cumulative path determination unit 150.

That is, the state coincidence determination unit 140 determines the error data by using the same characteristics of the initial state metric and the last state metric in the tail biting Viterbi decoding operation.

The reference cumulative path determining unit 150 determines whether the survival path information (eg, the cumulative path value for the survival path) satisfies the reference cumulative path value. Where the survival path is the survival path of the candidate data.

For example, a signal having a noise level may be received in an area where the base station 10 does not send data among various decodable candidate data. In this case, data may be detected through tail biting Viterbi decoding of the channel decoding unit 130. Here, the cumulative path value for the survival path of the detected data has a smaller value than the cumulative data value for the survival path of the normal data.

Accordingly, the reference cumulative path determining unit 150 may determine the error data through comparison with the reference cumulative path value that is set based on the cumulative data value for the survival path of the normal data. The reference cumulative path determiner 150 may remove candidate data determined as error data from the input candidate data. The reference cumulative path determiner 150 outputs candidate data from which error data has been removed to the cyclic redundancy check unit 160.

On the other hand, the reference cumulative path determination unit 150 will be described in detail with reference to FIG.

Here, the state coincidence determination unit 140 and the reference cumulative path determination unit 150 output a control signal for controlling the extraction operation of successive input candidate data to the candidate data extraction unit 110.

 Therefore, the candidate data extractor 110 may perform a candidate data extraction operation in response to the control signal.

The cyclic redundancy check unit 160 performs a cyclic redundancy check on the input candidate data. The cyclic redundancy check unit 160 determines the validity of the input data through the cyclic redundancy check. The cyclic redundancy check unit 160 outputs valid data of which the cyclic redundancy check is completed to the accumulation path alignment determination unit 170.

The cumulative path alignment determination unit 170 sorts all of the downlink control information (DCI) data determined as valid data through cyclic redundancy check based on survival path information (for example, cumulative path values for the survival path). . Here, the cumulative path value is received through the channel decoder 130. The cumulative path alignment determining unit 170 sorts all of the downlink control information (DCI) data determined as valid data through cyclic redundancy check using the cumulative path value in the order of less error. The cumulative path alignment determining unit 170 transmits a predetermined number of downlink control information data to the upper layer in the order of the least error to the upper layer.

Meanwhile, the cumulative path alignment determining unit 170 will be described in detail with reference to FIG. 4 below.

That is, according to the present invention, in order to remove error data that cannot be detected through the validity determination of the data through the cyclic redundancy checker, the state match determination unit 140, the reference accumulation path determination unit 150, and the accumulation path alignment determination unit ( 170).

The state match determination unit 140, the reference accumulation path determination unit 150, and the accumulation path alignment determination unit 170 may use the decoding characteristics (eg, tail biting Viterbi decoding characteristics) of the channel decoding unit 130. By detecting the error data, the error data is not transmitted to the upper layer.

As a result, the decoder 100 of the present invention can detect and remove error data. Through this, the decoder 100 may secure system stability by preventing system malfunction caused by downlink control information including error data. In addition, the decoder 100 may simplify an operation for detecting additional error data in an upper layer.

Meanwhile, the decoder according to the present invention may include all of the state matching determination unit 140, the reference accumulation path determination unit 150, and the accumulation path alignment determination unit 170, but the state matching determination unit 140 and the reference point. It may include at least one of the cumulative path determination unit 150 and the cumulative path alignment determination unit 170.

3 is a diagram illustrating a structure of a reference cumulative path determining unit according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the reference cumulative path determining unit 150 includes gain setting units 211, 212, 213, and 214, reference value setting units 221, 222, 223, and 224, a selection unit 230, and a comparison unit. 240.

The gain setting units 211, 212, 213, and 214 set a gain for setting a reference cumulative path value according to the cumulative number of derate matchings caused by the difference between the physical downlink control channel format and the DCI format. do. The gain setting units 211, 212, 213, and 214 may additionally set gains in consideration of radio channel environment information (eg, signal-to-noise ratio, signal-to-interference noise ratio, and the like), and may obtain a constant gain according to the radio channel environment. It is also possible to set a value or a variable gain value.

For example, if the first gain setting unit 211 satisfies Equation 1 below, the first gain setting unit 211 sets the first gain value gain1. The first gain setting unit 211 outputs the first gain value 221 to the first reference value setting unit 221.

When the second gain setting unit 212 satisfies Equation 2 below, the second gain setting unit 212 sets a second gain value gain2. The second gain setting unit 212 outputs a second gain value gain2 to the second reference value setting unit 222.

If the third gain setting unit 213 satisfies Equation 3 below, the third gain setting unit 213 sets a third gain value gain3. The third gain setting unit 213 outputs the third gain value gain3 to the third reference value setting unit 223.

The fourth gain setting unit 214 sets the fourth gain value gain4 when the following Equation 4 is satisfied. The fourth gain setting unit 214 outputs the fourth gain value gain4 to the fourth reference value setting unit 224.

The reference value setting units 221, 222, 223, and 224 may calculate the reference value set in advance based on the gain values gain1, gain2, gain3, and gain4 output from the gain setting units 211, 212, 213, and 214. have. Here, each of the gain values may have different values and may be set to various values according to system characteristics.

The first reference value setting unit 221 generates a first reference cumulative path value by calculating a first gain value with a predetermined reference value (reference value * gain1). The first reference value setting unit 221 outputs the first reference cumulative path value to the selection unit 230.

The second reference value setting unit 222 generates a second reference cumulative path value by calculating a second gain value with a predetermined reference value (reference value * gain2). The second reference value setting unit 222 outputs the second reference cumulative path value to the selection unit 230.

The third reference value setting unit 223 generates a third reference cumulative path value by calculating a third gain value with a predetermined reference value (reference value * gain3). The third reference value setting unit 223 outputs the third reference cumulative path value to the selection unit 230.

The fourth reference value setting unit 224 generates a fourth reference cumulative path value by calculating a fourth gain value with a predetermined reference value (reference value * gain4). The fourth reference value setting unit 224 outputs the fourth reference cumulative path value to the selection unit 230.

The selector 230 selects and outputs one reference cumulative path value among the first reference cumulative path value and the fourth reference cumulative path value in response to the selection signal. Here, the selection signal is a signal for selecting one of the first reference cumulative path value and the fourth reference cumulative path value according to the ratio of the physical downlink control channel format and the DCI format.

The comparison unit 240 compares the cumulative path value of the survival path received from the channel encoder with the reference cumulative path value. For example, the candidate data having a cumulative path value larger than the reference cumulative path value is output to the cyclic redundancy check unit 160.

That is, the reference cumulative path determining unit 150 adjusts the cumulative reference value according to the cumulative number of derate matchings generated by the difference between the format of the physical downlink control channel (PDCCH) and the format of the downlink control information (DCI). The influence of the accumulated path value due to the accumulation of noise signals can be minimized.

The reference accumulation path determiner 150 may remove error data even when noise is accumulated and error data is output from the channel encoder.

The cumulative path value of the survival path may be a survival path if the cumulative path value is large or a small cumulative path value may be a survival path depending on which metric or path metric is used.

Therefore, the reference cumulative path determiner 150 may set a reference value for setting the cumulative reference value according to the metric of the channel encoder.

4 is a diagram illustrating a structure of a survival cumulative path value determining unit according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the survival accumulation path value determining unit 170 includes a path value matching unit 311, 312, 313, and 319, and a data alignment unit 320.

The path value matching unit 310 matches each of the DCI data determined as valid data through the cyclic redundancy check with the cumulative path value. The path value matching unit 310 outputs valid data matched with the cumulative path value to the data alignment unit 310.

For example, the first path value matching unit 311 matches the first cyclic redundancy check valid data with the cumulative path value. The second path value matching unit 312 matches the second cyclic redundancy check valid data with the cumulative path value. The third path value matching unit 313 matches the second cyclic redundancy check valid data with the cumulative path value. The K th path value matching unit 319 matches the K th cyclic redundancy check valid data with the cumulative path value.

The data sorting unit 320 sorts the valid data for which the cyclic redundancy check is completed in the order of the smallest data error (that is, the smallest error data) using the cumulative path value. The data aligning unit 320 selects and outputs an upper layer of the terminal 20 and a predetermined number of valid data in order of decreasing errors.

In order to detect error data through analysis of downlink control information (DCI) data in an upper layer of the terminal 20, error detection information for this is required. However, since there is a lack of error detection information that can be obtained in a higher layer, there is a limit in filtering DCI in which error data is generated.

To this end, the survival cumulative path value determining unit 170 outputs downlink control information data in order of having a small error by using the cumulative path value of channel decoding, for example, tail biting Viterbi decoding. Therefore, it is possible to minimize the case where the error data cannot be filtered in the upper layer.

5 is a diagram illustrating a decoding operation of a decoder according to an embodiment of the present invention.

Referring to FIG. 5, in step S111, the candidate data extractor 110 extracts candidate data from demodulated data. The candidate data extractor 110 may extract candidate data from demodulated data received through the physical downlink control channel. The candidate data extractor 110 outputs the extracted candidate data to the derate matcher 120.

In operation S112, the derate matching unit 120 performs derate matching and subblock interleaving on candidate data. The derate matching unit 120 outputs the derate matching candidate data to the channel decoding unit 130.

In step S113, the channel decoding unit 130 performs channel decoding on the derate matching data. Here, the channel decoding may be a Viterbi decoding or a tail biting Viterbi decoding operation.

The channel decoding unit 130 outputs the survival path information selected through the Viterbi decoding operation to the reference cumulative path determining unit 150 and the cumulative path alignment determining unit 170. In addition, the channel decoding unit 130 transmits the survival path information selected through the tail biting Viterbi decoding operation to the state matching determination unit 140, the reference accumulation path determination unit 150, and the accumulation path alignment determination unit 170. Output Here, the survival path information includes, for example, a metric of the survival path or a cumulative path value of the survival path. In addition, the channel decoding unit 130 outputs the derate matched candidate data to the state matching determination unit 140.

In step S114, the state match determination unit 140 compares the initial state metric and the last state metric of the survival path information (eg, the state metric). As a result of the comparison, if the values of the initial state metric and the last state metric are equal to each other, the state coincidence determination unit 140 determines valid data.

However, if the value of the initial state metric and the last state metric are not equal to each other as a result of the comparison, it is determined as error data. The state coincidence determination unit 140 removes candidate data determined as error data from the derate matched candidate data. The state coincidence determination unit 140 outputs the candidate data from which the error data has been removed to the reference cumulative path determination unit 150.

In step S115, the reference cumulative path determining unit 150 determines whether survival path information (eg, a cumulative path value for the survival path) satisfies the reference cumulative path value. Where the survival path is the survival path of the candidate data. The reference cumulative path determining unit 150 may determine the validity (or error data) of the data by comparing with the reference cumulative path value that is set based on the cumulative data value of the normal data survival path. The reference cumulative path determiner 150 may remove candidate data determined as error data from the input candidate data. The reference cumulative path determiner 150 outputs candidate data from which error data has been removed to the cyclic redundancy check unit 160.

In step S116, the cyclic redundancy check unit 160 performs a cyclic redundancy check of the input candidate data. The cyclic redundancy check unit 160 determines the validity of the input data through the cyclic redundancy check. The cyclic redundancy check unit 160 outputs valid data of which the cyclic redundancy check is completed to the accumulation path alignment determination unit 170.

In step S117, the cyclic redundancy check unit 160 based on the survival path information (for example, the cumulative path value for the survival path) for all the downlink control information (DCI) data determined as valid data through the cyclic redundancy check Sort it. The cumulative path alignment determining unit 170 sorts all of the downlink control information (DCI) data determined as valid data through cyclic redundancy check using the cumulative path value in the order of less error.

In step S118, the cumulative path alignment determining unit 170 delivers a predetermined number of downlink control information data to the upper layer in the order of decreasing errors to the upper layer.

10: base station 20: terminal
110: candidate data extraction unit 120: derate matching unit
130: channel decoding unit 140: state matching determination unit
150: reference cumulative path determining unit 160: cyclic redundancy check unit
170: cumulative path alignment determination unit
211, 212, 213, 214: gain setting sections
221, 222, 223, 224: reference value setting sections
230: selection unit 240: comparison unit
311, 312, 313, and 319: path value matching unit
320: data sorting unit

Claims (18)

A candidate data extractor for extracting candidate data from demodulated data;
A derate matching unit for derate matching the extracted candidate data;
A channel decoding unit which performs channel decoding on the derate matched data;
A cyclic redundancy check unit configured to cyclically check the channel decoded candidate data to determine validity of the data; And
And a cumulative path alignment determination unit configured to output a predetermined number of downlink control channel data in order of decreasing errors according to the cumulative path value of the channel decoding. The method of claim 1,
And the channel decoding unit performs at least one of a Viterbi decoding operation and a tail biting Viterbi decoding operation. The method of claim 1,
Located between the channel decoding unit and the cyclic redundancy check unit, the state matching determination unit for receiving the survival path information through the channel decoding, and removes the error data by comparing the state of the initial metric and the last metric of the survival path information further Decoder to include. The method of claim 3, wherein
And the state coincidence determining unit determines the error data if the state of the initial metric and the last metric of the survival path information does not match. The method of claim 1,
And a reference accumulator path determining unit positioned between the channel decoding unit and the cyclic redundancy check unit and removing error data from the survival path information by determining whether a cumulative path value satisfies a reference cumulative path value. The method of claim 4, wherein
The reference cumulative path determination unit,
A gain setting unit configured to set a plurality of gain values according to sizes of the physical downlink control channel format and the control data channel format;
A reference value setting unit configured to generate a plurality of reference cumulative path values by calculating the plurality of gain values and a preset reference value;
A selection unit for selecting a reference cumulative path value corresponding to the gain value among the plurality of reference cumulative path values; And
And a comparator for removing error data by comparing the cumulative path value with the reference cumulative value. The method according to claim 6,
And the gain setting unit sets the gain value based on radio channel environment information. The method of claim 1,
The cumulative path alignment determination unit,
A path value matching unit for matching data channel information data determined as valid data through the cyclic redundancy check with valid information values of a survival path through the channel decoding; And
And a data alignment unit for sorting the valid data in the order of less error based on accumulated path values through the path value matching, and selecting and outputting a predetermined number of valid data in the sorted order. The method of claim 1,
And the demodulated data is data obtained by demodulating data received through a physical downlink control channel. In the error data removal method of the decoder,
Extracting candidate data from demodulated data;
Derate matching the extracted candidate data;
Performing channel decoding on the derate matched data;
Circularly checking the channel decoded candidate data to determine validity of the data; And
And outputting a predetermined number of downlink control channel data in order of decreasing errors according to the accumulated path value of the channel decoding. 11. The method of claim 10,
And the channel decoding is at least one of Viterbi decoding and tail biting Viterbi decoding. 11. The method of claim 10,
After the step of performing the channel decoding,
Receiving survival path information through the channel decoding, and removing error data by comparing a state of an initial metric and a last metric of the survival path information. The method of claim 12,
Removing the error data through the state comparison
If the state of the initial metric and the last metric of the survival path information does not match, determining the error data comprising the error data. 11. The method of claim 10,
After the step of performing the channel decoding,
And removing error data from the survival path information by determining whether a cumulative path value satisfies a reference cumulative path value. 15. The method of claim 14,
Removing the error data by determining whether the cumulative path value satisfies a reference cumulative path value
Setting a plurality of gain values according to sizes of a physical downlink control channel format and a control data channel format;
Generating a plurality of reference cumulative path values through calculation of the plurality of gain values and a preset reference value;
Selecting a reference cumulative path value corresponding to the gain value among the plurality of reference cumulative path values; And
And removing the error data by comparing the cumulative path value with the reference cumulative value. The method of claim 15,
The setting of the gain value
And setting the gain value based on wireless channel environment information. 11. The method of claim 10,
Outputting the downlink control channel data
Matching data channel information data determined as valid data through the cyclic redundancy check with valid information values of a survival path through the channel decoding; And
And sorting the valid data in the order of less error based on the accumulated path values through the path value matching, and selecting and outputting a predetermined number of valid data in the sorted order. 11. The method of claim 10,
And demodulating data is data obtained by demodulating data received through a physical downlink control channel.

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