KR20080112733A - Transmitting/receiving channel information and channel encoding in mobile communication system - Google Patents

Abstract

A channel information transmission/reception and channel coding in a mobile communications system are provided to channel-code the control channel information effectively and transmit/receive the control channel information. Information about a control channel encoded to a specific coding technique is received(S21). Control channel information is received in order to obtain the resource information in which the control channel is transmitted(S22). The control information by using the resource information in which the control channel is transmitted is received(S23).

Description

Transmitting / receiving channel information and channel encoding in mobile communication system

1 is a block diagram of exemplary control information according to a joint coding scheme.

3 is a flowchart for explaining a method for receiving control information according to an embodiment of the present invention.

3 is a flowchart for explaining a method for transmitting control information according to another embodiment of the present invention.

4 is a flowchart for explaining a channel encoding method according to another embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to channel information transmission and reception and channel coding in a mobile communication system.

Channel coding refers to a method for protecting a transmission signal from various signal transformation elements such as noise, interference, and fading. In other words, it corresponds to a field of signal conversion technology for improving communication performance by changing transmission signals through channel codes. As described above, when the transmission signal transmitted through channel encoding is decoded at the receiving end, an error detection or error correction technique may be used, thereby improving signal decoding performance and communication efficiency.

A case of detecting an error through the above-described channel coding will be described. When you want to send a transmission signal of 0 or 1, you send 00 or 11, respectively, for example, to send twice in succession. In this way, the receiving end may roughly receive a signal corresponding to one of 00, 01, 10, and 11. In this case, when 00 or 11 is received, it is received without error. When 01 or 10 is received, it is not 00 or 11 that is determined in advance.

In addition, a case of trying to correct an error through channel encoding will be described. When we want to transmit a transmission signal of zero or one, we promise to send three consecutive times, for example. For example, send 000 when you want to pass 0 information. At this time, even if one error occurs and 010 is received, two 0s remain, so that 000 may be transmitted according to the majority decision principle. This can be seen as correcting one error.

As described above, detection / correction of an error by encoding may be performed by inserting or adding redundancy information to information to be originally transmitted. When redundant information is added according to a predetermined rule, that is, channel coded transmission, it is possible to perform error detection / correction by checking whether the receiver follows the same rule used in channel coding.

Error detection / correction by encoding is a technique for improving reliability by adding surplus information in a form that is easy to be processed systematically with respect to digital information generated by source encoding on an original signal. The code used to add the surplus information to the original digital information is called a code, the code used for error detection is an error detection code (EDC), and the code used for correction is an error correction code (ECC). code).

In 1948, C. E Shannon proposed the so-called Shannon theory that if a certain condition is satisfied, the information can be transmitted with high reliability by encoding. Although this does not suggest a specific coding scheme, it can be seen as a way to study the code scheme. The beginning of the theory of code construction is the Haming code of 1950. This code was used to correct one error for the purpose of error correction of computer storage.

The error correction code is divided into a block code and a convolution code. Encoding 0 and 1 in the example above as 000 and 111 is an example of a block code. Thus, the block code is encoded into a series having a constant length. In contrast, convolutional codes are encoded sequentially and are encoded in a series of infinite lengths.

Codes used for such coding are Hamming code, Reed-Muller code, Reed-Solomon code, Convolution code, Turbo code, LDPC There are such things as a low density parity check code, and there are a plurality of coding codes.

An object of the present invention with respect to the prior art as described above is to propose a channel information transmission and channel encoding scheme.

According to an embodiment of the present invention, a method of receiving control information in a system in which control information about one or more terminals is transmitted during one downlink transmission unit includes receiving information on a control channel encoded by a specific encoding scheme. And decoding the received control channel information to obtain resource information through which a control channel is transmitted, and receiving the control information using the resource information through which the control channel is transmitted.

The specific encoding scheme may use one or more elementary sequences determined according to the length of the codeword generated by the encoding and the number of bits of the control channel information. In addition, the specific encoding scheme may generate one or more codewords having the same minimum distance value between each codeword.

The control channel information may be transmitted by being included in a control channel format indicator (CCFI) field defined at the beginning of a control information format from a base station.

The resource information on which the control channel is transmitted may be information on the number of OFDM symbols used for control channel transmission during the one downlink transmission unit.

A method of transmitting the control information in a system in which control information for one or more terminals is transmitted during one transmission unit according to another embodiment of the present invention is based on generating one or more codewords having the same minimum distance value between each codeword. Encoding information on a control channel by a coding scheme using a sequence; transmitting the coded control channel information; and transmitting the control information through the control channel.

In a system in which control information for one or more terminals is transmitted through a control channel during one transmission unit according to another embodiment of the present invention, a method of encoding information about the control channel may include resource information through which the control information is transmitted. Is a source encoding step consisting of control channel information consisting of bits and a channel encoding step of generating a codeword for the control channel information using at least one elementary sequence determined according to a codeword length and the control channel information. Include.

In the above-described embodiments, when the bit information consists of two bits of the first bit and the second bit, the base sequence is:

i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0

,

i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0 i 12 13 14 15 16 17 18 19 20 21 22 23 Mi, 0 One 0 One One 0 One 0 One 0 One 0 One Mi, 1 0 One One 0 One One 0 0 One One 0 0

,

i 0 One 2 3 4 5 6 7 8 9 Mi, 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One i 10 11 12 13 14 15 16 17 18 19 Mi, 0 One 0 One 0 One One 0 One 0 One Mi, 1 One 0 0 One One 0 One One 0 0

, And

i 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 One One Mi, 1 0 One One 0 0 One One 0 0 One One 0 0 One One 0 i 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Mi, 0 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 0 Mi, 1 One One 0 0 One One 0 0 One One 0 0 One One 0 0

You can use either. Where i is index information of a codeword sequence, and Mi, 0 and Mi, 1 are the base sequence multiplied by the first and second bits of the control channel information bits, respectively, to generate the i th information of the codeword sequence. Means information.

In order for the terminal to receive data and to decode the data allocated to the terminal, control information is transmitted. The control information of the OFDMA system downlink generally includes scheduling information for downlink data transmission, ACK / NACK information for uplink transmission, and scheduling grant for uplink transmission. Among them, the scheduling information for the downlink data transmission is information on how the UE processes the downlink data, and may be divided into three categories as shown in the following table.

Table 1 below describes the scheduling information of the control information.

Field Comment Cat. 1 (Resource indication) ID (UE or group specific) Indicates the UE (or group of UEs) for which the data transmission is intended Resource assignment Indicates which (virtual) resource units (and layers in case of multi-layer transmission) the UE (s) shall demodulate. Duration of assignment The duration for which the assignment is valid, could also be used to control the TTI or persistent scheduling. Cat. 2 (transport format) Multi-antenna related information Content depends on the MIMO / beamforming schemes selected. Modulation scheme QPSK, 16QAM, 64QAM. . In case of multi-layer transmission, multiple instances may be required. Payload size Interpretation could depend on e.g. modulation scheme and the number of assigned resource units (c.f. HSDPA). In case of multi-layer transmission, multiple instances may be required. Cat. 3 (HARQ) If asynchronous hybrid ARQ is adopted Hybrid ARQ process number Indicates the hybrid ARQ process the current transmission is addressing. Redundancy version To support incremental redundancy. New data indicator To handle soft buffer clearing. If synchronous hybrid ARQ is adopted Retransmission sequence number Used to derive redundancy version (to support incremental redundancy) and 'new data indicator' (to handle soft buffer clearing).

The first category Cat. 1 includes resource indications indicating resources to be allocated and may include, for example, fields of ID, resource assignment (RA), and duration of assignment (AD). Here, ID is an identifier for identifying each terminal, and in general, a MAC ID (C-RNTI) of a higher layer may be used as an ID of each terminal. Each terminal checks the ID from the received control information and determines whether the received control information is its own control information. The RA is information indicating which resource block is allocated to each UE, and after confirming the received RA, the UE may know which resource among the entire resources is transmitted. AD is information for informing the period in which control information is transmitted. By checking the received AD field information, it is possible to know how many TTIs (Transport Time Interval) control information is transmitted. Here, the TTI is related to the size of one frame as a transmission unit of data.

The second category Cat.2 includes information on a transport format and includes, for example, a field of information on a multi-antenna, a modulation method, and a payload size. Can include them. When the multi-antenna of each terminal is used, information and data related thereto are used among various modulation schemes, for example, QPSK, 16QAM, and 64QAM, and the size of the payload is defined in a second category (Cat. 2). It can be known from the control information.

The third category (Cat. 3) includes information related to HARQ. For example, when using asynchronous HARQ, HARQ process number, redundancy version, new data indicator (new data) information on an indicator) and information on a retransmission sequence number when using synchronous HARQ. Each terminal may know information related to retransmission of data from the third category (Cat. 3) control information.

A method of transmitting control information of terminals when data for a plurality of terminals is included in a given bandwidth, in particular, a method of transmitting the above-described scheduling information. There is a joint coding scheme in which separate coding to be transmitted to and control information for all terminals are configured at once, and even control information for other terminals can be received.

1 shows an example of control information configuration according to a joint coding scheme.

As shown in FIG. 1, control information transmitted over three OFDM symbols includes control information for terminals 1 to 8. FIG. In other words, control information for several terminals is configured at once according to a joint scheme. In addition, the control information configured in the joint manner is transmitted to the terminals through a control channel within a transmission time interval (TTI). Here, the control channel through which control information can be transmitted is related to the number of OFDM symbols for control information transmission or OFDM symbols for control channel.

The terminal must receive control information about the data in order to receive and decode the data allocated to the terminal. When control information of several terminals is transmitted together in one TTI in a given bandwidth, each terminal uses a blind detection scheme to receive its own control information among the control information of the various terminals. The blind detection method is a method of decoding all the given data until it finds its own data in a situation where it is not known whether the data transmitted from the base station is its own data or not. In order to use such a blind detection method, a method for determining whether the received data is own or not by using information unique to the terminal is required. As an example of such a method, in 3GPP, a CRC is masked on an ID which is an identifier of the terminal. (masking) is used.

In order to allocate resources for data transmission to a plurality of terminals in the OFDMA downlink, it is necessary to transmit appropriate control information from the base station to the terminal. Since the control information is necessary information for the terminal to correctly decode the data allocated to the terminal, accurate reception is required.

When control information of several terminals is mixed and transmitted as shown in FIG. 1, the receiving terminal does not know where its control information is located without measures for this. Accordingly, the terminal decodes all control information transmitted during the corresponding TTI until the terminal correctly receives the control information. As such, all the information is checked until the corresponding information is received without accurate resource information, that is, the blind detection method described above is used. In general, the blind detection method performed by all terminals to decode their control information is preferably performed on the OFDM symbols for the control channel within one TTI.

As described above, in the blind detection method, since the terminal performs decoding without accurate position information of its control information, there is a high probability that the number of times of decoding attempts is more than necessary.

In addition, in the configuration example as shown in FIG. 1, since the terminal receiving the control information from the base station does not know the exact position information of the control information but also the actual number of OFDM symbols to transmit the control information, because of this blind detection And the number of decoding attempts is increased.

Therefore, when the base station transmits control information for multiple terminals within a single TTI, information about the maximum number of OFDM symbols for control channel transmission is informed together and only for OFDM symbols corresponding to the maximum number of OFDM symbols for control channel transmission. It may be possible to attempt blind detection and decoding. However, even when transmitting only OFDM symbol information for maximum control channel transmission, the UE will attempt unnecessary detection and decoding when less OFDM is used than for OFDM symbol for maximum control channel transmission. In addition, it is necessary to transmit more accurate information considering that there are more cases in which fewer OFDM symbols are used than all OFDM symbols for maximum control channel transmission.

For example, even if the number of terminals scheduled in one sub-frame is small so that information of a plurality of terminals can be accommodated in two OFDM symbols, up to several OFDM symbols are transmitted from the viewpoint of the terminal. We will blindly detect and decode all OFDM symbols for maximum control channel transmission since we do not know whether they are used for This not only complicates decoding of the terminal but also directly affects power consumption.

In the present invention, the information on the number of OFDM symbols used for transmission of the control channel in order to reduce the number of attempts to decode the control information of each terminal when the control information for a plurality of terminals are mixed in one TTI of the OFDMA downlink We propose a method of transmitting and receiving.

Table 2 shows an example of a bit configuration for transmitting information about the number of OFDM symbols for control channel transmission proposed in the present invention.

Number of OFDM Symbols Used for Control Channel Transmission Bit Configuration of Control Channel Information 0 00 One 01 2 10 3 11

As shown in Table 2, when the maximum number of OFDM symbols for control channel transmission for one TTI is 3, the number of possible OFDM symbols for control channel transmission for the current TTI may be one of 0, 1, 2, and 3. Source encoding is performed to construct the bit information for each possible number of OFDM symbols for control channel transmission.

An example of a method of configuring bit information for the number of OFDM symbols for control channel transmission will be described, but the case where the maximum number of OFDM symbols for control channel transmission is 3 will be described as shown in Table 2.

수의 비트를 사용하여 제어 채널 송신용 OFDM 심볼 수를 알려줄 수 있다. 여기서,'

'연산을 수행하면 연산 대상이 되는 수 또는 수식의 결과보다 큰 최소 정수 값을 획득할 수 있다. 예를 들어 표 2에 나타난 바와 같이 최대 제어 채널 송신용 OFDM 심볼 수 즉, n 이 3인 경우

은 대략 1.58이므로

은 2가 된다. 따라서, 2 개의 비트를 사용하여 제어 채널 송신용 OFDM 심볼 수를 알려줄 수 있다.If the number of OFDM symbols for maximum control channel transmission set on the system is n,

The number of bits may be used to indicate the number of OFDM symbols for control channel transmission. here,'

If the operation is performed, a minimum integer value larger than the result of the number or the expression to be calculated may be obtained. For example, as shown in Table 2, when the maximum number of OFDM symbols for the control channel transmission, that is, n is 3

Is approximately 1.58,

Becomes two. Therefore, two bits can be used to inform the number of OFDM symbols for control channel transmission.

As described above, when the maximum number of OFDM symbols for control channel transmission is 3, two bits may be used to inform the number of OFDM symbols for control channel transmission. For example, when the number of OFDM symbols for control channel transmission is 0, 1, 2, and 3, a bit configuration of 00, 01, 10, and 11 may be used to inform the number of OFDM symbols for control channel transmission.

The number of OFDM symbols for the control channel transmission and the bit configuration thereof shown in Table 2 is only one configuration example, but the number of the OFDM symbols for the control channel transmission and the bit configuration thereof is not necessarily the same as shown in Table 2, and various The case may be applied in a similar way.

As described above, in order to transmit the bit configuration of the number of OFDM symbols for control channel transmission as control information through encoding, control channel information indicating the number of OFDM symbols for control channel transmission is transmitted in a transmission format. The field will have to be configured.

Table 3 shows an example of field definitions for transmitting control channel information indicating the number of OFDM symbols for control channel transmission.

Cat. 0 (CCFI: control channel format indicator) field comment Number of OFDM Symbols for Control Channel Transmission

비트의 길이를 갖는다. (n=시스템에서 설정되는 최대 제어 채널 송신용 OFDM 심볼 수)The number of OFDM symbols for control channel transmission.

Has the length of the bit. (n = maximum number of OFDM symbols for control channel transmission set in the system)

As shown in Table 3, since the field configured to transmit the OFDM symbol number information for control channel transmission is necessary information for receiving and decoding the control information of the terminal as shown in Table 1, the field is separately from the control information as shown in Table 1 It is desirable to be transmitted. Table 3 is an example of field definitions configured to transmit such information. And cat. The 0 information, that is, the control channel format indicator (CCFI), is effectively transmitted to a predetermined position where all terminals can know so that all corresponding terminals can be received without error.

A method of receiving control channel information and control information using a field configured to transmit the number of OFDM symbols for control channel transmission proposed in this embodiment is as follows.

2 is a flowchart illustrating a method of receiving control information according to an embodiment of the present invention.

Referring to FIG. 2, first, in step S21, the terminal receives control channel information. In order to reduce the error rate when the terminal receives the control channel information, as described above, the control channel information, that is, cat. The 0 information is preferably transmitted from the transmitting side through a preset position or resource.

In addition, since the control channel information as described above is information to be transmitted with high reliability to all terminals, the channel coding is performed and transmitted. In this case, channel coding may be performed through various channel coding methods, but it is preferable that appropriate channel coding is performed in relation to the small number of information bits. A channel encoding method suitable for encoding control channel information according to an embodiment of the present invention will be described in detail later.

Then, in step S22, the terminal receiving the above control channel information decodes the control channel information received before detecting and decoding the control information, and resource information, for example, the number of OFDM symbols for control channel transmission. Information is obtained, and in step S23, control information is received using resource information for which the control channel is transmitted, for example, the number of OFDM symbols for control channel transmission. In other words, the UE performs blind detection only on OFDM symbols corresponding to the number of OFDM symbols for control channel transmission to receive and decode control information.

A method of transmitting control channel information and control information using a field configured to transmit the number of OFDM symbols for control channel transmission proposed in this embodiment is as follows.

3 is a flowchart for explaining a method of transmitting control information according to another embodiment of the present invention.

First, in step S31, the number of OFDM symbols for control channel transmission in the TTI to be transmitted is determined, and the control channel information for the number of OFDM symbols for control channel transmission is configured to perform channel encoding.

In this case, channel coding may be performed through various channel encoding methods as described above. However, it is preferable that appropriate channel encoding is performed in connection with a small number of information bits. A channel encoding method suitable for encoding control channel information according to an embodiment of the present invention will be described in detail later.

In step S32, the channel-encoded control channel information is transmitted to one or more terminals, and in step S33, control information is transmitted to one or more terminals. In this case, the control channel information and the control information may be transmitted through the same channel or may be transmitted through different channels.

In this case, the base station may transmit to the terminals related to the control information and / or data transmitted in the TTI to be transmitted in a unicast method, which is a one-to-one transmission method, or multicast, which is a group transmission method, to related terminals. The transmission may be performed in a multicast manner, or may be transmitted in a broadcast manner, which is a broadcast transmission scheme for all terminals, without specifying a specific receiving terminal.

In this case, as described above, the terminal is preferably transmitted from the transmitting side through a preset position or resource in order to reduce an error rate in receiving the control channel information.

As described above, since the control channel information is information to be transmitted with high reliability to all terminals, channel coding is preferably performed. When coding control channel information, such as a hamming code, lead-muller code, reed-solomon code, convolutional code, turbo code, etc. Various symbols may be used.

비트를 사용하는 표 2의 예와 같이 2~3 비트 정도가 제어 채널 송신용 OFDM 심볼 수를 나타내는 제어 채널 정보를 구성할 수 있다. 이와 같이 채널 부호화 대상이 되는 정보가 적은 비트로 구성되는 경우에는 짧은 길이의 정보에 대해 보다 효과적으로 채널 부호화를 수행할 수 있는 방법을 사용할 수 있다. 채널 부호화 대상이 되는 정보가 적은 비트로 구성되더라도 일반적으로 의미 있는 부호가 되기 위해서는 데이터 비트수가 적어도 2 비트가 되는 것이 바람직하다.In general, when a control channel and a data channel are transmitted in a system, control channel information indicating the number of OFDM symbols for control channel transmission is applied when a time division multiplexing (TDM) method, which is divided and multiplexed for each time axis, for example, OFDM symbols, is applied. The number of bits to configure is small. For example, the maximum number of OFDM symbols for control channel transmission is n

As in the example of Table 2 using bits, two to three bits may constitute control channel information indicating the number of OFDM symbols for control channel transmission. As described above, when the information to be encoded is composed of fewer bits, a method of performing channel encoding on the information of short length can be used more effectively. Even if the information to be encoded is composed of fewer bits, it is generally desirable that the number of data bits be at least two bits in order to be meaningful.

Hereinafter, a channel encoding method according to an embodiment of the present invention will be described. In the following description of channel coding, when channel coding is performed on the control channel information which is the number of OFDM symbols for control channel transmission described above, the case where the control channel information consists of 2 bits will be described. A result of performing channel encoding on a bit string consisting of predetermined bits is defined as a codeword.

When channel coding control channel information, a basic sequence is used according to an embodiment of the present invention. The base sequence may be adaptively selected and used for a codeword length.

First, Table 4 shows an example of an elementary sequence that can be used when channel coding 2-bit control channel information into a codeword consisting of 12 bits.

i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0

In Table 4, i is index information of a codeword sequence, and Mi, 0 and Mi, 1 are multiplied by the first and second bits of the control channel information bits, respectively, to generate the i th information of the codeword sequence. It means basic sequence information.

That is, a total of 11 bits of codewords can be generated by using a result of sequentially multiplying each of the bits of the currently transmitted control channel information and the values of i, Mi, 0, and Mi, 1 for 0 to 11, respectively. have. In this case, since the result of multiplying each bit of the control channel information with the values of Mi, 0, and Mi, 1 must be represented in binary, that is, 0 or 1, a modulo operation may be additionally performed. . For example, when the control channel information to be transmitted is 01, referring to the part of Table 4 for i = 0, when {(0 × 1) + (1 × 0)} mod 2 is calculated, a value of 0 is obtained. . This obtained value corresponds to the first bit of the codeword sequence. In this way, the bitwords of the remaining i = 1 to 11 may be obtained to obtain a codeword including 12 bits.

Equation 1 shows a method of obtaining the above-described codeword sequence.

Equation 1 bi is the i-th bit information of the codeword sequence, a _n is the n-th information of the bit information, Mi, n is the multiplied by each bit of the bit information to generate the i-th information of the codeword sequence The basic sequence information is a value that can be obtained through, for example, Table 4. In this case, since the codeword length is assumed to be 12, i may be one or more values from 0 to 11 (i = 0, ..., 11).

Table 5 shows codewords generated by performing channel encoding on each control channel information possible through Table 4 and Equation 1 described above.

Control channel information Codeword 00 000000000000 01 011001100110 10 101010101010 11 110011001100

When encoding is performed by the method described through the present embodiment, codewords having the same minimum distance between each codeword may be generated. As described above, when the minimum distance value between each codeword generated through channel encoding is the same, there is an excellent effect in terms of encoding performance.

Here, the minimum distance indicates a difference value between each codeword. For example, calculating the minimum distance value between each codeword for control channel information 01 and 10 in Table 5, i is different because the bits corresponding to 0, 1, 4, 5, 8, and 9 are different. It can be seen that the distance value is 6. In addition, if the minimum distance value between each codeword for the control channel information 10 and 11 of Table 5 is calculated, the bits corresponding to 1, 2, 5, 6, 9, and 10 are different from each other. It can be seen that the distance value is 6. In this way, when the minimum distance value for each codeword is calculated, all have a value of 6, and as described above, it can be confirmed that the minimum distance of each codeword is the same.

In addition, when using {12, 2} code that encodes two bits to generate a 12-bit codeword, 12-bit codewords are generated. Because of the mapping to carriers, 12 subcarriers are accurately fit on the particles of a 3GPP LTE system having one resource block (RB), and thus an easy effect is expected in signal processing. On the contrary, if the code for generating the codeword is selected in consideration of the scheduling resource unit, the above-described effect can be obtained.

In another embodiment of Table 6, an example of an elementary sequence that can be used when channel coding 2-bit control channel information into a codeword consisting of 24 bits is shown.

i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0 i 12 13 14 15 16 17 18 19 20 21 22 23 Mi, 0 One 0 One One 0 One 0 One 0 One 0 One Mi, 1 0 One One 0 One One 0 0 One One 0 0

As in Table 4, in Table 6, i is index information of the codeword sequence, and Mi, 0 and Mi, 1 are the first and second bits of the control channel information bit, respectively, to generate the i-th information of the codeword sequence. Means the base sequence information to be multiplied by.

In this case, since the codeword length is assumed to be 24, i may be one or more values from 0 to 23 (i = 0, ..., 23).

Table 7 shows codewords generated by performing channel encoding on each control channel information possible through Table 6 and Equation 1 described above.

Bit configuration Codeword 00 00000000000000000000000 01 011001100110011011001100 10 101010101010101101010101 11 110011001100110110011001

When encoding is performed by the method described through the present embodiment, codewords having the same minimum distance between each codeword may be generated. It can be seen that the minimum distance calculation value between each codeword is 12 when referring to the description of the minimum distance value described through Table 5. As described above, when the minimum distance value between each codeword generated through channel encoding is the same, there is an excellent effect in terms of encoding performance.

In addition, when using (24, 2) codes that encode two bits to generate a 24-bit codeword, a 24-bit codeword is generated, and thus, when sub-carriers are mapped using a BPSK modulation scheme, the 24 sub-carriers are used. In the case of the QPSK modulation method, the symbol is mapped to 12 subcarriers, so that 12 subcarriers are exactly matched to particles of a 3GPP LTE system having one RB (resource block). An easy effect is expected. On the contrary, if the code for generating the codeword is selected in consideration of the scheduling resource unit, the above-described effect can be obtained.

In another embodiment of Table 8, an example of an elementary sequence that can be used when channel encoding 2-bit control channel information into a codeword consisting of 20 bits is shown.

i 0 One 2 3 4 5 6 7 8 9 Mi, 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One i 10 11 12 13 14 15 16 17 18 19 Mi, 0 One 0 One 0 One One 0 One 0 One Mi, 1 One 0 0 One One 0 One One 0 0

As in Table 4, in Table 8, i is index information of a codeword sequence, and Mi, 0 and Mi, 1 are first and second bits of the control channel information bit, respectively, to generate i-th information of the codeword sequence. Means the base sequence information to be multiplied by.

In this case, since the codeword length is assumed to be 20, i may be one or more values from 0 to 19 (i = 0, ..., 19).

Table 9 shows codewords generated by performing channel encoding on each control channel information possible through Table 8 and Equation 1 described above.

Bit configuration Codeword 00 00000000000000000000 01 01100110011001101100 10 10101010101010110101 11 11001100110011011001

When encoding is performed by the method described through the present embodiment, codewords having the same minimum distance between each codeword may be generated. It can be seen that the minimum distance calculation value between each codeword is 10 when referring to the description of the minimum distance value described through Table 5. As described above, when the minimum distance value between each codeword generated through channel encoding is the same, there is an excellent effect in terms of encoding performance.

In another embodiment of Table 10, an example of an elementary sequence that can be used when channel encoding 2-bit control channel information into a codeword consisting of 32 bits is shown.

i 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 One One Mi, 1 0 One One 0 0 One One 0 0 One One 0 0 One One 0 i 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Mi, 0 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 0 Mi, 1 One One 0 0 One One 0 0 One One 0 0 One One 0 0

As in Table 4, in Table 10, i is index information of a codeword sequence, and Mi, 0 and Mi, 1 are first and second bits of the control channel information bits, respectively, to generate i-th information of the codeword sequence. Means the base sequence information to be multiplied by.

In this case, since the codeword length is assumed to be 32, i may be one or more values from 0 to 31 (i = 0, ..., 31).

Table 11 shows codewords generated by performing channel encoding on each control channel information possible through Table 10 and Equation 1 described above.

Bit configuration Codeword 00 00000000000000000000000000000000 01 01100110011001101100110011001100 10 10101010101010110101010101010100 11 11001100110011011001100110011000

When encoding is performed by the method described through the present embodiment, codewords having the same minimum distance between each codeword may be generated. It can be seen that the minimum distance calculation value between each codeword is 16 when referring to the description of the minimum distance value described through Table 5. As described above, when the minimum distance value between each codeword generated through channel encoding is the same, there is an excellent effect in terms of encoding performance.

4 is a flowchart for explaining a channel encoding method according to another embodiment of the present invention.

Referring to FIG. 4, first, at step S41, information for identifying a resource to which control information is transmitted is composed of control channel information consisting of binary bits through source encoding. As described above, the number of OFDM symbols for control channel transmission can be used as a resource for transmitting control information. In this case, the control channel information is configured for the number of OFDM symbols for control channel transmission.

For example, if the maximum number of OFDM symbols for control channel transmission is 3, the possible number of OFDM symbols for control channel transmission may be 0, 1, 2, 3. The control channel information may be configured using a total of 2 bits. More specifically, 00 when the number of OFDM symbols for control channel transmission is 0, 01 when the number of OFDM symbols for control channel transmission is 1, and OFDM symbol for control channel transmission. If the number is 2, the control channel information of 10 may be configured. If the number of OFDM symbols for control channel transmission is 3, the control channel information of 11 may be configured.

Here, the maximum number of OFDM symbols for control channel transmission, the number of bits used for control channel information, and the mapping scheme between the number of possible OFDM symbols for control channel transmission and the bit configuration are not limited to the above-described example, and various cases are the same or similar. Applicability is obvious.

In step S42, channel encoding is performed using the control channel information generated in step S41 and a basic sequence. Here, it is preferable that the elementary sequence is a sequence capable of setting the same minimum distance value between each codeword generated through channel encoding with respect to each control channel information. The base sequence uses a sequence corresponding to the codeword length generated through channel coding.

For example, one of the elementary sequences shown in Tables 4, 6, 8, and 10 may be selected and used. Here, the base sequences shown in Tables 4, 6, 8, and 10 may generate codewords having the same value as the minimum distance value between each codeword, and each of them is classified according to the codeword length. In other words, Table 4 corresponds to a (12, 2) code whose codeword length is 12, which is generated through channel coding, and 24 corresponds to a codeword length generated by channel coding, which is 24 (24). , 2) code, and in Table 8, the codeword length generated through channel encoding corresponds to a (20, 2) code, which is 20. Finally, in Table 10, the codeword generated through channel encoding is generated. Corresponds to a (32, 2) code whose codeword length is 32. Accordingly, an appropriate base sequence may be selected and used according to a codeword length to be generated through channel encoding.

While using the above-described base sequence and the control channel information generated through step S41 together, the above-described equation (1) may be applied to perform channel encoding, that is, to generate a codeword.

When control information of various terminals is transmitted within one TTI through the embodiments of the present invention described above, the terminal receiving the terminal does not know where its control information is located and thus receives its control information correctly. The blind detection method that decodes all the control information until it is effective can be used more efficiently. In other words, in the blind detection method, since the terminal performs decoding without accurate position information of its own control information, the number of times of decoding attempts is more than necessary. If you don't even know if is located, then the number of attempts to decode will be higher. In particular, since the number of terminals scheduled in one subframe is small, even if information of several terminals is accommodated in only two OFDM symbols, the terminal does not know how many OFDM symbols are used for control channel transmission. There is a case where blind detection and decoding of all OFDM symbols corresponding to the maximum number of OFDM symbols for control channel transmission occur. This not only increases the decoding complexity of the terminal but also directly affects the power consumption increase.

As suggested by the present invention, a frame is configured to include a field for transmitting information on the number of OFDM symbols for control channel transmission in a corresponding subframe in addition to the general control information of the terminal as shown in Table 1, and all terminals are indicated in the corresponding field. It is possible to perform blind detection and decoding only on symbols.

This is expected to have a very advantageous effect in terms of power constraints terminal.

In addition, when channel coding control channel information consisting of bit information with respect to the number of OFDM symbols for control channel transmission using one or more basic sequences proposed by the present invention and Equation 1, channel coding is performed on the control channel information. Since each codeword has a minimum distance value of the same value as each other, an excellent effect is expected in terms of code performance.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. You will know. For example, although the present invention has been described with respect to the control channel, the scheme of the present invention may be applied to any channel.

In other words, it is to be understood that this patent is not to be limited by the embodiments shown herein but is to be accorded the broadest scope consistent with the principles and features disclosed herein.

According to one embodiment of the present invention as described above, it is possible to transmit and receive control channel information. In addition, it is possible to channel code the control channel information effectively.

Claims (8)

A method of receiving control information in a system in which control information for one or more terminals is transmitted during one downlink transmission unit, Receiving information about a control channel encoded by a specific encoding scheme; Decoding the received control channel information to obtain resource information on which a control channel is transmitted; And Receiving the control information by using the resource information through which the control channel is transmitted Control information receiving method comprising a. The method of claim 1, And the specific encoding scheme uses one or more elementary sequences determined according to the length of the codeword generated by the encoding and the number of bits of the control channel information. The method of claim 1, The specific encoding scheme is a control information receiving method, characterized in that for generating one or more codewords having the same minimum distance value between each codeword. The method of claim 1, The control channel information is included in the control channel format indicator (CCFI) field defined at the beginning of the control information format is transmitted, characterized in that, The method of claim 1, The resource information on which the control channel is transmitted is information on the number of OFDM symbols used for control channel transmission during the one downlink transmission unit. In the method for transmitting the control information in a system in which control information for at least one terminal is transmitted during one transmission unit, Encoding information on a control channel with an encoding scheme using an elementary sequence for generating one or more codewords having the same minimum distance value between each codeword; Transmitting the encoded control channel information; And Transmitting the control information over the control channel Control information transmission method comprising a. In a method of encoding information on the control channel in a system in which control information for at least one terminal is transmitted through a control channel for one transmission unit, A source encoding step of configuring the resource information for transmitting the control information into control channel information consisting of bits; And Channel coding generating a codeword for the control channel information using at least one elementary sequence determined according to a length of a codeword and the control channel information Channel information encoding method comprising a. The method of claim 7, wherein When the bit information consists of two bits of the first bit and the second bit, the base sequence is i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0 , i 0 One 2 3 4 5 6 7 8 9 10 11 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One One 0 i 12 13 14 15 16 17 18 19 20 21 22 23 Mi, 0 One 0 One One 0 One 0 One 0 One 0 One Mi, 1 0 One One 0 One One 0 0 One One 0 0 , i 0 One 2 3 4 5 6 7 8 9 Mi, 0 One 0 One 0 One 0 One 0 One 0 Mi, 1 0 One One 0 0 One One 0 0 One i 10 11 12 13 14 15 16 17 18 19 Mi, 0 One 0 One 0 One One 0 One 0 One Mi, 1 One 0 0 One One 0 One One 0 0 , And i 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Mi, 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 One One Mi, 1 0 One One 0 0 One One 0 0 One One 0 0 One One 0 i 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Mi, 0 0 One 0 One 0 One 0 One 0 One 0 One 0 One 0 0 Mi, 1 One One 0 0 One One 0 0 One One 0 0 One One 0 0 A channel encoding method, wherein i is index information of a codeword sequence, and Mi, 0 and Mi, 1 are the control channel information, respectively, to generate i-th information of the codeword sequence. Meaning the base sequence information that is multiplied by the first and second bits of a bit).

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