KR101392011B1 - Apparatus and method for transmission and reception of control information in mobile telecommunication system - Google Patents

Abstract

In the mobile communication system, the control information is encoded so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in control information may be performed a plurality of times, And mapping the generated symbols to a physical channel and transmitting the mapped symbols to the physical channel, and at least one symbol generated corresponding to the at least one specific bit of the plurality of symbols is a physical channel, Wherein at least one of the plurality of symbols is mapped to at least one second RE that is closest to a first RE to which a pilot symbol is mapped among a plurality of Resource Elements (REs) included in a channel, The symbols generated corresponding to the remaining bits except for one specific bit are the same as the symbols 1RE and the at least one second RE, and the plurality of REs have different time and frequency indices.

Linear Error Correcting Code, Unequal error protection, CQI, LTE, Channel estimation, interpolation,

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for transmitting and receiving control information in a mobile communication system,

The present invention relates to an apparatus and method for transmitting / receiving control information in a mobile communication system, and more particularly, to an apparatus and method for transmitting / receiving control information transmitted in an uplink in a mobile communication system.

Generally, a mobile communication system has been developed to provide communication while ensuring activity to a user. Due to the rapid development of the technology, such a mobile communication system has evolved into a form capable of providing high-speed data communication as well as voice communication.

2. Description of the Related Art In recent mobile communication systems, a single carrier frequency division multiple access (OFDMA) scheme or a similar carrier frequency division multiple access - Frequency Division Multiple Access (hereinafter referred to as "SC-FDMA"). Currently, the 3rd Generation Partnership Project (3GPP), an asynchronous cellular mobile communication standard group, is studying a LTE (Long Term Evolution) or an E-UTRA (Evolved Universal Terrestrial Radio Access) system based on the multiple access scheme.

In the above multiple access scheme, the data or control information of each user is classified and operated so that the time and frequency resources for transmitting data or control information for each user do not overlap each other, that is, orthogonality is established. do. In the case of the control channel, the control information of each user can be distinguished by further allocating the code resources.

In the LTE system, uplink control information includes ACK (acknowledgment) / NACK (negative acknowledgment) feedback information, which is a signal for responding to the successful reception of downlink data transmission, CQI (Channel Quality Indication Feedback information required for MIMO operation, or a combination of the ACK / NACK, CQI, and MIMO feedback information. The ACK / NACK information is generally composed of 1-bit, and is repeatedly transmitted in order to improve reception performance and expand cell coverage. In a system to which MIMO is applied, ACK / NACK information is transmitted for each MIMO codeword. Generally, the CQI information is composed of a plurality of bits for expressing a channel state, and is channel-coded and transmitted for improving reception performance and enlarging cell coverage. The channel coding method for the CQI information may be a block coding method or a convolutional coding method.

In the case of control information composed of a plurality of bits such as the CQI, a method of enhancing reception reliability for an important bit by performing channel coding with different error correction capabilities for each bit position constituting the control information is possible. For example, in a High Speed Downlink Packet Access (HSDPA) system, CQI information composed of 5 bits is channel-coded by (20, 5) block coding, and channel-coded for 1 bit of most significant bit (MSB) Method is applied.

In the LTE system, uplink control information is divided into transmission formats depending on the presence or absence of data transmission. When data and control information are simultaneously transmitted in an uplink, the data and control information are time-division multiplexed (TDM), mapped to a time-frequency resource allocated for data transmission, and transmitted. On the other hand, when only control information is transmitted without data transmission, a specific allocated frequency band is used for control information transmission. The physical channel for transmitting only the control information is defined as a Physical Uplink Control Channel (PUCCH), and the PUCCH is mapped to the allocated specific frequency band as discussed in the standard conference.

1 is a diagram illustrating a transmission structure of a PUCCH, which is a physical channel for control information transmission in an uplink in a current 3GPP LTE system. Hereinafter, a concrete transmission structure of the PUCCH will be described with reference to FIG.

In FIG. 1, the horizontal axis represents a time domain and the vertical axis represents a frequency domain. The range of the time domain is one subframe 102, and the range of the frequency domain is the system transmission bandwidth 110. [ The subframe 102, which is the basic transmission unit of the uplink, has a length of 1 ms and one subframe is composed of two slots 104 and 106 each having a length of 0.5 ms. Each of the slots 104 and 106 includes a plurality of SC-FDMA symbols 111 to 123 and 131 to 143. In FIG. 1, one slot is composed of 7 SC-FDMA symbols. The smallest unit of the frequency domain is a subcarrier, and the basic units of resource allocation are resource blocks (RBs) 108 and 109. The RBs 108 and 109 are composed of a plurality of subcarriers and a plurality of SC-FDMA symbols. Herein, for example, 14 SC-FDMA symbols constituting 12 subcarriers and 2 slots constitute one RB. Referring to FIG. 1, a frequency band to which the PUCCH is mapped corresponds to reference numeral 108 or reference numeral 109, which is an RB corresponding to both ends of the system transmission band 110. The PUCCH can apply frequency hopping in order to increase the frequency diversity during one subframe.

This will be described with reference to FIG. The control information # 1 is transmitted through the pre-allocated frequency band 108 in the first slot 104 and the frequency hopping is transmitted through the other pre-allocated frequency band 109 in the second slot 106. [ On the other hand, the control information # 2 is transmitted through the pre-allocated frequency band 109 in the first slot 104, the frequency hopping is performed in the second slot 106, and is transmitted through the other pre-allocated frequency band 108 do.

1, SC-FDMA symbols, reference numerals 111, 113, 114, 115, 117, 138, 140, 141, 142, 144 or reference numerals 131, 133, 134, 135, 137, Reference signals (RS) are transmitted to SC-FDMA symbols, reference numerals 112, 116, 139 and 143 or reference numerals 132, 136, 119 and 123, Quot;) is transmitted. The pilot is composed of a predetermined sequence and is used for channel estimation for coherent demodulation at the receiving end. The number of SC-FDMA symbols for transmission of the control information, the number of SC-FDMA symbols for RS transmission, and the corresponding positions in the subframe are examples, and may be changed according to the type of control information to be transmitted or the system operation.

When the control information is transmitted through the PUCCH in the LTE system operating as described above, it is necessary to define a specific transmission method for increasing the reception reliability of the control information. However, up to now, no specific method for increasing the reliability of reception of the control information when transmitting control information through the PUCCH in the LTE system has been proposed.

Therefore, the present invention provides a transmitting and receiving apparatus and method for enhancing the reliability of control information transmitted in a reverse direction in a mobile communication system.

The present invention provides a transmitter and receiver and a method for enhancing the reliability of control information transmitted in a PUCCH in a 3G LTE system.

According to the present invention, there is provided an apparatus and method for transmitting / receiving control information, which improves the reliability of control information transmitted in the reverse direction to prevent unnecessary retransmission and increase system efficiency.

A method according to an embodiment of the present invention comprises: A method for transmitting an uplink control information in a mobile communication system, the method comprising the steps of: receiving a control information including at least one specific bit for which a highest reception reliability is required among a plurality of bits included in control information, And mapping the generated symbols to a physical channel; and transmitting symbols mapped to the physical channel, wherein the at least one of the plurality of symbols, At least one symbol generated corresponding to a bit is mapped to at least one second RE closest to a first RE to which a pilot symbol is mapped among a plurality of Resource Elements (REs) included in the physical channel, Bits of the plurality of bits, excluding the at least one specific bit, The symbol generation in response to the are, and one of the plurality of RE mapping the remaining RE other than the first 1RE and the at least one of the 2RE, the plurality of RE are characterized by having a different time and frequency indices.
Another method according to an embodiment of the present invention comprises: A method for receiving a reverse control information in a mobile communication system, the method comprising: receiving a signal through a physical channel; detecting encoded symbols from the received signal; decoding the detected symbols to detect control information Wherein the encoded symbols are symbols encoded so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information can be performed a plurality of times, At least one symbol corresponding to the at least one specific bit of the coded symbols is allocated to at least one of the plurality of resource elements (REs) included in the physical channel, Wherein the first symbol is mapped to the second symbol, and among the plurality of bits, The symbols corresponding to the remaining bits except for a specific bit of the REs are mapped to the REs other than the first RE and the second RE among the plurality of REs, .

An apparatus according to an embodiment of the present invention includes: A reverse control information transmission apparatus in a mobile communication system, the reverse control information transmission apparatus comprising: a control information transmitting unit configured to transmit control information to at least one specific bit requiring a highest reception reliability among a plurality of bits included in control information, A mapping unit for mapping the generated symbols to a physical channel; and a transmitter for transmitting the symbols mapped to the physical channel, wherein the at least one of the plurality of symbols At least one symbol generated corresponding to a bit is mapped to at least one second RE closest to a first RE to which a pilot symbol is mapped among a plurality of Resource Elements (REs) included in the physical channel, Of the plurality of bits excluding the at least one specific bit The symbols generated in correspondence with the plurality of REs are mapped to the REs other than the first RE and the at least one second RE among the plurality of REs, and the plurality of REs have different time and frequency indices .
Another apparatus according to an embodiment of the present invention includes: A reverse control information receiving apparatus in a mobile communication system, comprising: a receiver for receiving a signal through a physical channel; a control unit for detecting encoded symbols from the received signal; a decoder for decoding the detected symbols and detecting control information; Wherein the encoded symbols are symbols encoded so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information can be performed a plurality of times, At least one symbol generated corresponding to the at least one specific bit of the coded symbols is at least one of a plurality of resource elements (REs) included in the physical channel, Wherein the first symbol is mapped to one second RE, and among the plurality of bits, Wherein the symbols generated corresponding to the remaining bits except for the at least one specific bit are mapped to the REs other than the first RE and the at least one second RE among the plurality of REs, Time and frequency indexes.

The present invention provides a method for transmitting / receiving control information in the case of increasing the reliability of a specific bit of control information to be transmitted, thereby reducing a bit error rate or a block error rate and improving reliability .

Hereinafter, the operation principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification. The operation of the present invention will be described with reference to a transmission direction of a specific transmission system or control information (for example, Uplink or downlink).

The present invention proposes a method for increasing the reliability of a specific bit of control information to be transmitted. The control information includes ACK (acknowledgment) / NACK (negative acknowledgment) feedback information, a CQI (Channel Quality Indication) information for feedback of the channel state, a multi-input / output antenna Feedback information necessary for MIMO (Multiple Input Multiple Output) operation, or a combination of the ACK / NACK, CQI, and MIMO feedback information. The ACK / NACK information is generally composed of 1-bit, and is repeatedly transmitted (repetition) in order to improve reception performance and expand cell coverage. In a system to which MIMO is applied, ACK / NACK information is transmitted for each MIMO codeword. Generally, the CQI information is composed of a plurality of bits for expressing a channel state, and is channel-coded and transmitted for improving reception performance and enlarging cell coverage. As a channel coding method for the CQI information, block coding is assumed.

In the case of control information composed of a plurality of bits, such as CQI, a method for increasing the reception reliability for the significant bits is needed. For example, when the channel state to be represented by the CQI is composed of a plurality of bits, a case in which the least significant bit (LSB) is erroneously recognized as compared with a case where the receiving terminal erroneously recognizes the most significant bit (MSB) Relatively less impact on system performance, such as system throughput. Therefore, high reception reliability is required for the MSB if possible. Therefore, there is a method of strongly adding error correction capability to important bits in the channel encoding step. Hereinafter, a method of strongly adding an error correction capability to a significant bit is referred to as "method 1 ". For example, in a High Speed Downlink Packet Access (HSDPA) system, CQI information composed of 5 bits is channel-coded by (20, 5) block coding, but strong channel coding is applied to 1 bit of MSB. (20, 5) block coding for CQI applied in HSDPA will be described in more detail as follows.

The (20, 5) code for coding CQI of High Speed Downlink Packet Access (HSDPA) defined in 3GPP standard TS25.212 uses basis sequences shown in Table 1 below.

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

(20,5) channel coding is applied by linear combination of five base code sequences having a length of 20 and input information composed of 5 bits, which are illustrated in Table 1 using the following Equation (1) .

(i = 0, ..., 19)

(i = 0, ..., 19)

Where a _n is the n-th information bit to be encoded, where a ₀ is LSB and a ₄ is MSB. The b _i is an i-th output bit for channel coding of the information bits, and is an encoded bit. Thus, 20 bits of coded bits are generated from 5 bits of input information. In particular, the base code stream illustrated in Table 1 is characterized in that an error correction capability is additionally given to the MSB a ₄ . Specifically, the base-station arrays include base-station calls M _{i, n} (i = 15, 16, 17, 18, 19, n = 0, 1, 2, 3, 4) is set to M _{i, 4} = 1 (i = 15, 16, 17, 18, 19) and the rest are all set to 0, resulting in multiplying M _{i, 4} by Equation MSB a ₄ is repeated 5 times. That is, the (20, 5) block coding performs an equivalent operation to the MSB a ₄ by repeating the MSB a _{4 four} times after performing (15, 5) block coding on the 5 bits of the input information, Correction capability is additionally given.

The addition of an error correction capability to an information bit at a specific position as described above is called an Unequal Error Protection (UEP). By appropriately configuring the base code string, it is determined at what position the information bit is additionally given a certain level of error correction capability.

In the LTE system, (N, K) block coding having UEP characteristics as described above can be applied to CQI information transmission. In this case, N represents the size of the encoded bit string, and K represents the size of the input bit string.

Next, a method of mapping a modulation symbol including an important bit of the control information to a position where channel estimation is relatively accurate when mapping the coded and modulated symbols to the physical channel will be described. In the following description, the method is referred to as "method 2 ".

1, control information is transmitted through a pre-allocated frequency band 108 in the first slot 104, frequency hopping is performed in the second slot 106, The data is transmitted through the data transmission unit 109 as an example. 1, a pilot (referred to as a pilot signal (RS)) is mapped to specific SC-FDMA symbols, that is, 112, 116, 139 and 143 in one subframe, The control information is mapped and transmitted to the base stations 111, 113, 114, 115, 117, 138, 140, 141, 142 and 144, respectively. The number of SC-FDMA symbols for transmission of the control information, the number of SC-FDMA symbols for RS transmission, and the corresponding positions in the subframe are examples, and may be changed according to the type of control information to be transmitted or the system operation. The channel state of the radio transmission path through which the control information is transmitted is estimated from a pilot composed of a predetermined sequence between the transceivers and compensated for the received signal, so that the receiver obtains the control information. Therefore, the higher the accuracy of the channel estimation, the higher the reliability of reception of the control information. 1, when the pilot and control information share a limited radio resource, the receiver needs a channel estimation method for deriving a channel value for a time interval in which a pilot is not mapped from an actual pilot-mapped symbol Do. In the example of FIG. 1, the channel estimation for the control information transmitted through the first slot 104 and the pre-allocated frequency band 108 is generally mapped to SC-FDMA symbols 112 and 116 and transmitted The channel estimation for the control information transmitted through the second slot 106 and frequency hopping and pre-allocated frequency band 109 is generally performed by interpolating the SCs of reference numbers 139 and 143, -PDMA symbol, and interpolating the pilots that are mapped to the FDMA symbol. The channel estimation method based on the interpolation generally has a problem in that the symbols that are far from the pilot used for the interpolation have a relatively low channel estimation capability while the channel estimation capability for the symbols located at the periphery of the pilot used for interpolation is excellent . 1, the channel estimation capability of each SC-FDMA symbol position with respect to the control information transmitted through the first slot 104 and the pre-allocated frequency band 108 is determined based on the pilot-mapped SC-FDMA symbol In the SC-FDMA symbols mapped to the positions of the reference numerals 113 and 115 located between the periphery of the reference symbols 112 and 116, in particular, between the two pilot symbols. The channel estimation capability of each SC-FDMA symbol position for the control information transmitted through the second slot 106 and the pre-allocated frequency band 109 is represented by reference numerals 139 and 143, which are pilot-mapped SC- In particular, the SC-FDMA symbols mapped to the positions 140 and 142 located between the two pilot symbols.

Therefore, when mapping the coded and modulated symbols to a physical channel, a modulation symbol including an important bit of the control information is preferentially mapped to a position having a relatively high channel estimation capability in consideration of the characteristics, Lt; RTI ID = 0.0 > bit < / RTI >

In the present invention, the 'method 1' and the 'method 2' described above are combined and designed to increase the reception reliability of important bits of control information to be transmitted through a channel coding and symbol mapping method as follows .

2 is a conceptual diagram for explaining a process of mapping control information to a physical channel according to the present invention. The overall operation of the present invention will be described below with reference to FIG.

First, the control information to be transmitted is channel-coded (200). The channel coding is performed by applying (N, K) block coding having UEP characteristics as described above. The (N, K) block coding has the same result as the concatenation result of (N1, K) block coding and (N2, K ') block coding. In this case, N represents the size of the encoded bit stream, K represents the size of the input bit stream, and N = N1 + N2, K > K '. That is, when encoding the K-bit control information, the error correction capability is relatively good for some K 'bits of the input information. The basis sequences having optimal performance for the (N, K) block coding having the UEP characteristics are values determined according to the values of N, K, N1, N2 and K '. For example, Represents a base code string for (20, 5) block coding, which makes the error correction capability relatively strong for one MSB of input information. The (N, K) block coding operation is performed by linear combination of K base code strings having length N and input information composed of K bits, and can be expressed by Equation (2) below. In Equation (2), a (n) is the n-th information bit to be encoded, and a (0) is the LSB (Least Significant Bit) and a (K-1) is the MSB (Most Significant Bit). b (i) is an i-th output bit, i.e., an encoded bit, on which channel encoding is performed for the input information bits. And M _{i, n} denote the base codes used for the (N, K) block coding.

(i = 0, 1, ... , N - 1)

(i = 0, 1, ..., N - 1)

The last N2 bits 201, i.e. b (N-N2), b (N-N2 + 1), ... of the coded bits b , b (N-2), and b (N-1) provide additional error correcting capability for the K 'bits of K input information.

Then, the coded bits b (i) generate a modulation symbol through a modulation process in step 202. The modulation process is determined according to the modulation scheme, and the modulation symbol modulated according to the predetermined modulation scheme is composed of x consecutive coded bits. For example, x = 1 when using the BPSK modulation method, x = 2 when using the QPSK modulation method, x = 3 when using the 8PSK modulation method, and x = 4 when using the 16QAM modulation method do.

Hereinafter, for convenience of description, it is assumed that the structure of a subframe in which the control information is mapped and transmitted is as shown in FIG. Then, a total of 10 SC-FDMA symbols except four SC-FDMA symbols to which a pilot is mapped in one subframe can be used for the control information transmission. Therefore, a modulation symbol for a total of 10 pieces of control information can be mapped to the 10 SC-FDMA symbols for transmission of control information and transmitted. That is, a physical channel mapping operation 203 is performed in FIG. The physical channel mapping operation 203 maps the important information to the periphery of the pilot symbol in order to maintain the channel estimation capability relatively to the important information as described in the 'method 2'. FIG. 2 illustrates a case where the last N2 bits 201, i.e., b (N-N2), and b (i) of the coded bits of the control information to be transmitted, M (6), m (7), m (8), m (9), and the modulation symbols composed of N (N-N2 + 1), ..., b ) Is shown by the reference numeral 204.

Therefore, the SC-FDMA symbols s (1), s (3), s (6), m (7), m ), m (8), and m (9) constituting the modulation symbols m (6), m (7), m (8), and m So that the overall system performance is improved. This utilizes a feature that only information on a specific input bit can be separated from an output bit string of block coding having UEP characteristics. In general block coding, information on all input bits is mixed in the output bit string of block coding The information on a specific input bit can not be separated. The remaining modulation symbols m (0), m (1), m (2), m (3), m (4), and m ), s (4), s (5), s (7), s (9).

On the other hand, an interleaving operation for a modulation symbol may be defined to obtain an effect equivalent to the above-described physical channel mapping operation. That is, the modulation symbols m (0), m (1), m (2), m (3), m (4), m (5), m (6), m (7) m 9 to be mapped to a subframe in which the control information is transmitted sequentially. The interleaving operation is defined so that the above-described important control information can obtain a property with relatively good channel estimation capability. For example, if the interleaving result is m (0), m (6), m (1), m (7), m (2), m (3) m (5), and mapping the interleaved modulation symbols to the subframe in which the control information is transmitted in order, so that the important control information can obtain a property with relatively good channel estimation capability.

FIG. 3 and FIG. 4 are operational flowcharts for transmission of control information according to an embodiment of the present invention. Hereinafter, the operation of transmitting control information according to the present invention will be described with reference to FIGS. 3 and 4. FIG.

First, Fig. 3 will be described. In step 300, the transmitter generates control information to be transmitted. The transmitter then encodes the control information generated in step 302 so as to have a UEP characteristic. Since the UEP characteristic has been described above, it will not be described here. In step 304, the transmitter modulates the encoded symbols to have the UEP characteristics as described above, and maps the symbols to the corresponding physical channels in step 306. [ In performing mapping to the physical channel, as described above, control is performed so that some significant bits of the control information are mapped to positions having relatively good channel estimation capability. And then transmits the mapped control information as described above.

Next, a description will be made with reference to FIG. In step 400, the transmitter generates control information to be transmitted. The transmitter then encodes the control information generated in step 402 so as to have a UEP characteristic. Since the UEP characteristic has been described above, it will not be described here. The transmitter modulates the encoded symbols to have the UEP characteristics as described above in step 404, and performs interleaving in step 406. FIG. At this time, the interleaving is interleaved such that the interleaving output for the modulation symbol is mapped to a position where some significant bits of the control information have relatively good channel estimation capability, as described above. Thereafter, the transmitter proceeds to step 408 to map the interleaved symbols to the physical channel, and transmits the mapped control information through the physical channel in step 410.

When the control information described above is transmitted, the reception operation of the control information can be expressed by the receiver in the reverse order and inverse operation to the series of operations described above. Hereinafter, an operation of the receiver will be described with reference to the accompanying drawings.

5 and 6 are flowcharts of operations of receiving control information according to an embodiment of the present invention. Here, FIG. 5 is a diagram of a reception operation corresponding to FIG. 3, and FIG. 6 is a diagram of a reception operation corresponding to FIG.

In step 500, the receiver receives a predetermined signal. Here, since only the control information is considered, it is assumed that the received signal means a signal including control information. When a signal having control information is received, the receiver performs physical channel demapping in step 502 and extracts a modulation symbol for the control information from the physical channel to which the control information is mapped. In the extracting operation, the receiver performs channel estimation and channel compensation on the received signal from the received pilot symbols, and then reconstructs the modulation symbols in the original order. Then, the receiver performs demodulation on the reconstructed modulation symbol in step 504, and decodes the demodulated symbol in step 506 to obtain control information.

Next, the reception operation of FIG. 6 corresponding to FIG. 4 will be described. In step 600, the receiver receives a predetermined signal. Here, since only the control information is considered, it is assumed that the received signal means a signal including control information. When the signal having the control information is received in step 602, the receiver extracts a modulation symbol for the control information from the physical channel to which the control information is mapped from the signal received through the physical channel demapping. In the extracting operation, the receiver performs channel estimation and channel compensation on the received signal from the received pilot symbols. In step 604, the receiver performs a deinterleaving operation to reconstruct modulation symbols in the original order with respect to the extracted signal. The receiver then demodulates the reconstructed modulation symbol in step 606 and decodes the demodulated symbol in step 608 to obtain the control information transmitted by the transmitter.

≪ Embodiment 1 >

The first embodiment is an example in which control information composed of 5 bits is (20, 5) block coded and mapped to a physical uplink control channel (PUCCH), which is a physical channel for transmission of the control information, .

7 is a conceptual diagram for explaining a process of mapping control information to a physical channel according to the first embodiment of the present invention.

The (20, 5) block coding is characterized in that it has a relatively high error correction capability with respect to the MSB 1 bit 708 of the control information to be input, and the basis code sequence is shown in Table 1 As shown above. The control information includes control information composed of a plurality of bits, for example, CQI information for feedback of the channel state, feedback information necessary for operation of the MIMO antenna, or ACK / NACK feedback A combination of information, a combination of the control information, and the like. In the case where the control information includes a combination of CQI information and ACK / NACK feedback information, ACK / NACK is generally mapped to MSB since high reception reliability is required for ACK / NACK feedback information. In step 702, a process of encoding the control information a (0) to a (4) composed of the 5 bits by applying the base code sequence shown in Table 1 is shown. Therefore, when the encoding is performed as described above, a total of 20 bits of encoded bits b (0) to b (19) are generated. Among the coded bits, b (15) to b (19) and 710 represent the result of repeating the MSB a (4) of the input control information five times. Therefore, the (20, 5) block coding provides additional error correction capability for the MSB a (4) of the input control information.

In step 704, the coded bits are modulated to generate modulation symbols. By applying QPSK modulation using this modulation method, for example, one modulation symbol is generated from two consecutive coded bits sequentially. That is, a modulation symbol m (0) is generated from the encoded bits b (0) and b (1) and a modulation symbol m (1) is generated from the encoded bits b M (0) to m (9), which are modulation symbols. Therefore, the modulation symbols m (7), m (8), and m (9) 712 are coded bits b (15) to b (19) ). ≪ / RTI > Therefore, when mapping the modulation symbols to the PUCCH, the modulation symbols m (7), m (8), and m (9) including information on the MSB a (4) The receiver reliability for a (4) is further increased by mapping the channel estimation capability to a relatively good position.

If the structure of the PUCCH to which the control information is mapped has two pilot symbols per slot and a total of four pilot symbols 716, 724, 730, and 738 exist in one subframe, channel estimation is performed for each slot The channel estimation performance is relatively good at the positions closest to the pilot symbols 718, 722, 732, and 736 between two pilot symbols in each slot. Therefore, a modulation symbol including information on a modulation symbol to increase the reception reliability or information on some specific control information bits to improve the reception reliability is preferentially mapped to the positions of the reference numerals 718, 722, 732, and 736, The modulation symbols are mapped to positions other than the positions where the modulation symbols including the information on the modulation symbols or the specific control information bits to improve the reception reliability are to be mapped.

7, the modulation symbol m (7) is mapped to s (1) 718, m (8) is mapped to s (3) 722, m (9) The remaining modulation symbols m (0) to m (6) are sequentially mapped to positions where m (7), m (8), and m (9) are not mapped.

If the number of points having a relatively good channel estimation capability is x, a modulation symbol for improving the reception reliability or a certain control information bit for improving the reception reliability during the time period during which the control information is transmitted, When the number of modulation symbols including information is y and the total number of modulation symbols is z;

1) When x = y,

- map the y modulation symbols one-to-one to the x different positions.

- z-y modulation symbols to the positions where the y modulation symbols are not mapped, respectively.

- Additionally, z-y modulation symbols mapped as above can be mixed for randomization. That is, z-y modulation symbols may be interleaved.

2) When x < y,

- Select x modulation symbols among the y modulation symbols and map them one by one to the x different positions.

- z-x modulation symbols to the positions where the x modulation symbols are not mapped, respectively.

- Additionally, the z-x modulation symbols mapped as above can be mixed for randomization. That is, z-x modulation symbols may be interleaved.

3) when x> y,

- maps the y modulation symbols to some of the x different positions and maps them. The y positions selected from the x different positions are reduced as much as possible so that the mapped modulation symbols can be compensated by the remaining symbols even if the channel environment experiences a drastic deteriorated state.

- z-y modulation symbols to the positions where the y modulation symbols are not mapped, respectively.

- Additionally, z-y modulation symbols mapped as above can be mixed for randomization. That is, z-y modulation symbols may be interleaved.

The time interval over which the control information is transmitted is generally one subframe and may be composed of a plurality of subframes for transmitting a large amount of control information. The mapping operation can be implemented with an interleaving operation having the same effect.

8 is a block diagram of a control information transmitting apparatus according to an embodiment of the present invention.

Referring to FIG. 8, the control information generating apparatus 802 receives information on which control information is to be transmitted from the controller 810, and generates corresponding control information according to the format of control information to be transmitted. For example, when it is desired to transmit 5-bit CQI information, CQI information is generated from the downlink channel state information received from the controller 810. The control information generator 802 may be included in the controller 810. The channel encoder 804 receives the type of the control information to be encoded from the controller 810, calculates a coding rate and a UEP degree for the control information that is predetermined according to the type of the control information, And performs channel coding by reflecting information such as specific bit information to be encoded. In the first embodiment, the generated 5-bit CQI information is added with an error correction capability through the (20, 5) block coding (804). At this time, an additional error correction capability is added to the MSB of the CQI information. The channel-encoded signal is generated as a modulation symbol in a modulator 806. In general, the QPSK scheme is applied to the CQI information. The physical channel mapper 808 performs an operation of mapping the generated modulation symbols to the PUCCH, which is a physical channel for transmitting control information. Specifically, the mapping operation maps modulation symbols including information on a modulation symbol to improve reception reliability or some specific control information bits to improve reception reliability to a position having a relatively superior channel estimation capability. And the remaining modulation symbols can be sequentially mapped to positions where the modulation symbols are not mapped. Alternatively, the remaining modulation symbols may be mapped to obtain a further randomization effect. The controller 810 provides a specific mapping rule that defines a mapping operation of a modulation symbol based on a channel estimation capability for each time interval position from the physical channel mapper 808. [

9 is a block diagram of a control information transmitting apparatus according to another embodiment of the present invention.

The configuration and the overall operation of the control information transmitting apparatus of FIG. 9 are the same as those of the apparatus of FIG. However, in FIG. 9, the interleaver 908 and the physical channel mapper 912 perform the mapping operation of the modulation symbols based on the channel estimation capability for each time interval position performed by the physical channel mapper 808 of FIG. That is, the interleaver 908 receives the interleaving rule of the modulation symbol based on the channel estimation capability for each time interval position from the controller 910, mixes the order of the modulation symbols input from the modulator 906 based on the interleaving rule, (912) sequentially maps the interleaved modulation symbols to the PUCCH. Other configurations are the same as those described in Fig. 8, and therefore, it is assumed that they will not be further discussed here.

10 is a block diagram of a control information receiving apparatus according to an embodiment of the present invention.

10, a receiver receives a predetermined signal from a receiver 1010, extracts a signal mapped to the PUCCH from a reception signal received from the receiver 1010 in a physical channel demapper 1000, The estimator / compensator 1001 performs channel estimation from the pilot symbols of the extracted PUCCH signal and performs channel compensation on the received PUCCH signal. The deinterleaver 1002 rearranges the channel-compensated signal by applying a deinterleaving rule or a demapping rule received from the controller 1008. The deinterleaving rule or demapping rule is a rule corresponding to an interleaving rule or a physical channel mapping rule in the transmitter, and serves to reduce the order of signals in the original order. The rearranged signal is demodulated in a demodulator 1004, and then decoded in a decoder 1006 to a channel encoder of a transmitter. In the first embodiment, since the control information is (20, 5) block coded having UEP characteristics, the decoder 1006 performs decoding operation of (20, 5) block coding having UEP characteristics. The decoder 1006 receives decoding related information of a signal to be decoded from the controller 1008, such as a decoding method, a coding rate, and a degree of UEP. From the decoded result, the receiver can obtain the control information transmitted by the transmitter.

Meanwhile, even when a general channel coding method having no UEP characteristic is applied, the effect of increasing the reception reliability of an important bit can be obtained by applying a symbol mapping method or an interleaving method based on the channel estimation capability for each time domain position . However, in this case, the increase in the reception reliability that is increased for the significant bits may be smaller than the case of applying the symbol mapping method or the interleaving method based on the UEP-based channel coding method and the channel region-based channel estimation capability.

&Lt; Embodiment 2 >

The channel estimation performance is affected by the channel estimation algorithm implemented in the receiver, the rate of change of the radio channel environment, the structure of the pilot symbol, and the like. Generally, the channel estimation performance is relatively good at the periphery of the pilot symbol, but there may be a case where the channel estimation performance is different. For example, in a case where the radio channel environment hardly changes, there may be a case where the channel estimation performance is excellent through the channel estimation through the combination at the center of two pilot symbols in terms of the received signal to noise ratio of the pilot symbol. Therefore, in the second embodiment, the symbol mapping method or the interleaving method based on the channel estimation capability for each time interval position among the operations of the first embodiment is changed to change modulation symbols to improve reception reliability or some specific control And to map a modulation symbol containing information on the information bits to the middle point of the two pilot symbols in the slot.

Specifically, the second embodiment is an example in which control information composed of 5 bits is (20, 5) block-coded and mapped to a physical uplink control channel (PUCCH), which is a physical channel for transmitting the control information, .

11 is a conceptual diagram illustrating a process up to mapping to a physical channel for transmitting control information according to a second embodiment of the present invention.

The (20, 5) block coding is characterized in that it has a relatively high error correction capability with respect to the MSB 1 bit 1108 of the control information to be input, and the basis code sequence is shown in Table 1 As shown above. The control information includes control information composed of a plurality of bits, for example, CQI information for feedback of the channel state, feedback information necessary for operation of the MIMO antenna, or ACK / NACK feedback A combination of information, a combination of the control information, and the like. In the case where the control information includes a combination of CQI information and ACK / NACK feedback information, ACK / NACK is generally mapped to MSB since high reception reliability is required for ACK / NACK feedback information.

The coding process of the reference numeral 1102 shows that the control information composed of the 5 bits is encoded by applying a (0) to a (4) to the base code sequence shown in Table 1 above. Therefore, when the encoding process 1102 is performed, a total of 20 bits of encoded bits b (0) to b (19) are generated. Among the coded bits, b (15) to b (19) 1110 represent the result of repeating the MSB a (4) five times in the input control information, so that the error correction capability for a (4) to provide.

In the process 1104 of generating a modulation symbol, the coded bits are generated according to a modulation scheme determined according to a predetermined rule or a predetermined rule. For example, when a QPSK modulation scheme is applied, one modulation symbol is sequentially generated from two consecutive coded bits to generate m (0) to m (9) as a total of 10 modulation symbols. Therefore, the modulation symbols m (7), m (8), and m (9) 1112 are encoded bits b (15) to b (19) that give additional error correction capability to the MSB a 1110).

In the physical channel mapping process 1106, the modulation symbol is mapped to the PUCCH. When the modulation symbols are padded to the PUCCH, the modulation symbols m (7), m (8), and m (9) including information on the MSB a (4) To thereby further increase the reception reliability for a (4).

If the structure of the PUCCH to which the control information is mapped has two pilot symbols per slot and a total of four pilot symbols 1116, 1124, 1130, and 1138 exist in one subframe, channel estimation is performed for each slot (720, 734) among the two pilot symbols in each slot in terms of the received signal to noise ratio of the pilot symbol. Accordingly, a modulation symbol including information on a modulation symbol to increase the reception reliability or information on a specific control information bit to improve the reception reliability is preferentially mapped to the positions of the reference numbers 720 and 734, Mapping is performed to a position other than a mapped position of a modulation symbol for improving reception reliability or a modulation symbol including information for a specific control information bit to improve reception reliability. 11, the modulation symbols m (8) are mapped to s (2) 1120 and m (9) are mapped to s (7) 1134 and the remaining modulation symbols m (0) Indicates that the m (8) and m (9) are sequentially mapped to the unmapped positions. In the example of FIG. 11, the modulation symbol m (7) includes only a part of the information on the coded bits of a (4) to improve the reception reliability relatively and the channel estimation performance is relatively high Since the point is limited to two places, it indicates that mapping priority is lower than m (8) or m (9).

More generally, the number of points where the channel estimation capability is relatively good is x, the modulation symbol to increase the reception reliability, or the information about some specific control information bits to improve the reception reliability during the time period during which the control information is transmitted Is y, and the total number of modulation symbols is z;

1) When x = y,

- map the y modulation symbols one-to-one to the x different positions.

- z-y modulation symbols to the positions where the y modulation symbols are not mapped, respectively.

In addition, the z-y modulation symbols mapped as described above may be mixed for randomization. That is, the mapped z-y modulation symbols may be interleaved.

2) When x < y,

- Select x modulation symbols among the y modulation symbols and map them one by one to the x different positions.

- z-x modulation symbols to positions where the x modulation symbols are not mapped, respectively.

In addition, the z-x modulation symbols mapped as described above may be mixed for randomization. That is, the mapped z-x modulation symbols may be interleaved.

3) when x> y,

- maps the y modulation symbols to some of the x different positions and maps them. The y positions selected from the x different positions are reduced as much as possible so that the mapped modulation symbols can be compensated by the remaining symbols even if the channel environment experiences a drastic deteriorated state.

- z-y modulation symbols to the positions where the y modulation symbols are not mapped, respectively.

- Additionally, z-y modulation symbols mapped as above can be mixed for randomization.

The time interval over which the control information is transmitted is generally one subframe and may be composed of a plurality of subframes for transmitting a large amount of control information. The mapping operation can be implemented with an interleaving operation having the same effect.

The transmitting and receiving apparatuses of the second embodiment each follow the description of FIG. 8, FIG. 9, and FIG. 10 of the first embodiment. However, a symbol mapping method or an interleaving method based on a channel estimation capability for each time interval position is not limited to a modulation symbol for improving reception reliability or a modulation symbol including information for some specific control information bits for improving reception reliability, Map to the center point of the two pilot symbols.

Meanwhile, even when a general channel coding method having no UEP characteristic is applied, the effect of increasing the reception reliability of an important bit can be obtained by applying a symbol mapping method or an interleaving method based on the channel estimation capability for each time domain position . However, in this case, the increase in the reception reliability that is increased for the significant bits may be smaller than the case of applying the symbol mapping method or the interleaving method based on the UEP-based channel coding method and the channel region-based channel estimation capability.

In the first and second embodiments described above, a channel coding method (hereinafter referred to as 'method 1') having a UEP characteristic and a symbol mapping method or an interleaving method (hereinafter referred to as 'method 2') based on channel- When applied together, it has been described that each method is applied redundantly to specific bits to be particularly enhanced in the control information to be transmitted. However, with the channel coding method having the UEP characteristic, bits for increasing the reliability of reception can be configured differently by a symbol mapping method or an interleaving method based on the bit for improving the reception reliability and the channel estimation capability for each time interval position. That is, the former exhibits the effect of increasing the reliability of receiving A by a 'method 1' and a 'method 2' for A, which is a set of bits or bits in the control information, And increases the reception reliability for C, which is a set of bits or bits different from B, which is a bit or set of bits, to 'method 2'. Therefore, in the latter case, the reception reliability increase for B, which is a set of bits or bits, and the reception reliability increase for C, which is a bit or a set of bits, may be different.

1 is a diagram illustrating a transmission structure of a PUCCH, which is a physical channel for transmission of control information in an uplink in a current 3GPP LTE system,

FIG. 2 is a conceptual diagram for explaining a process of mapping control information to a physical channel according to the present invention;

FIG. 3 and FIG. 4 are flowcharts of operations of transmitting control information according to an embodiment of the present invention;

FIG. 5 and FIG. 6 are flowcharts of operations of receiving control information according to an exemplary embodiment of the present invention,

FIG. 7 is a conceptual diagram for explaining a process of mapping control information to a physical channel according to the first embodiment of the present invention;

8 is a block diagram of a control information transmitting apparatus according to an embodiment of the present invention;

9 is a block diagram of a control information transmitting apparatus according to another embodiment of the present invention;

10 is a block diagram of a control information receiving apparatus according to an embodiment of the present invention.

FIG. 11 is a conceptual diagram illustrating a process up to mapping to a physical channel for transmitting control information according to a second embodiment of the present invention; FIG.

Claims (20)

A method for transmitting a reverse control information in a mobile communication system, Generating a plurality of symbols by coding the control information so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information is performed a plurality of times; Mapping the generated symbols to a physical channel; And transmitting the mapped symbols to the physical channel, Wherein at least one symbol generated in correspondence with the at least one specific bit among the plurality of symbols includes at least one of a plurality of resource elements (REs) included in the physical channel, Wherein the first and second REs are mapped to at least one second RE and symbols generated corresponding to the remaining bits of the plurality of bits except for the at least one specific bit, Wherein the plurality of REs are mapped to the REs other than the at least one second RE, and the plurality of REs have different time and frequency indices. The method according to claim 1, Wherein the at least one specific bit includes a Most Significant Bit (MSB) among the plurality of bits. The method according to claim 1, Wherein the at least one specific bit indicates one of ACK (acknowledgment) information and NACK (Negative ACK) information. The method according to claim 1, And the remaining bits are sequentially mapped to the remaining REs or are mapped randomly to the remaining REs. The method according to claim 1, The at least one specific bit may include at least one of a plurality of pilot symbols located between an RE to which a first pilot symbol is mapped and an RE to which a second pilot symbol is mapped among the plurality of pilot symbols, Wherein the at least one third RE is mapped to one third RE and the at least one third RE indicates at least one RE that is the farthest in distance from the first pilot symbol and the second pilot symbol. A reverse control information transmission apparatus in a mobile communication system, An encoder for generating a plurality of symbols by coding the control information so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information can be performed a plurality of times; A mapper for mapping the generated symbols to a physical channel, And a transmitter for transmitting symbols mapped to the physical channel, Wherein at least one symbol generated in correspondence with the at least one specific bit among the plurality of symbols includes at least one of a plurality of resource elements (REs) included in the physical channel, Wherein the first and second REs are mapped to at least one second RE, among the plurality of symbols, symbols generated corresponding to the remaining bits except for the at least one specific bit among the plurality of bits, Wherein the plurality of REs are mapped to the REs other than the at least one second RE, and the plurality of REs have different time and frequency indices. The method according to claim 6, Wherein the at least one specific bit includes a Most Significant Bit (MSB) among the plurality of bits. The method according to claim 6, Wherein the at least one specific bit indicates one of ACK (acknowledgment) information and NACK (Negative ACK) information. The method according to claim 6, And the remaining bits are sequentially mapped to the remaining REs or are mapped randomly to the remaining REs. The method according to claim 6, The at least one specific bit may include at least one of a plurality of pilot symbols located between an RE to which a first pilot symbol is mapped and an RE to which a second pilot symbol is mapped among the plurality of pilot symbols, Wherein the at least one third RE is mapped to one third RE and the at least one third RE indicates at least one RE that is farthest in distance from the first pilot symbol and the second pilot symbol. A method for receiving a reverse control information in a mobile communication system, Receiving a signal through a physical channel, Detecting coded symbols from the received signal; And detecting control information by decoding the detected symbols, Wherein the encoded symbols are symbols encoded so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information can be performed a plurality of times, Wherein at least one symbol corresponding to the at least one specific bit of the coded symbols includes at least one of a plurality of resource elements (REs) included in the physical channel, Wherein symbols corresponding to the remaining bits of the coded symbols, except for the at least one specific bit among the plurality of bits, are mapped to the second RE of the first RE and the at least one Wherein the plurality of REs are mapped to the other REs except for the second RE, and the plurality of REs have different time and frequency indices. 12. The method of claim 11, Wherein the at least one specific bit comprises a Most Significant Bit (MSB) among the plurality of bits. 12. The method of claim 11, Wherein the at least one specific bit indicates one of ACK (acknowledgment) information and NACK (Negative ACK) information. 12. The method of claim 11, And the remaining bits are sequentially mapped to the remaining REs or are mapped randomly to the remaining REs. 12. The method of claim 11, The at least one specific bit may include at least one of a plurality of pilot symbols located between an RE to which a first pilot symbol is mapped and an RE to which a second pilot symbol is mapped among the plurality of pilot symbols, Wherein the at least one third RE is mapped to a third RE and the at least one third RE indicates at least one RE that is the farthest in distance from the first pilot symbol and the second pilot symbol. In a reverse control information receiving apparatus in a mobile communication system, A receiver for receiving a signal via a physical channel, A controller for detecting coded symbols from the received signal; And a decoder for decoding the detected symbols to detect control information, Wherein the encoded symbols are symbols encoded so that an error correction process for at least one specific bit requiring a highest reception reliability among a plurality of bits included in the control information can be performed a plurality of times, Wherein at least one symbol corresponding to the at least one specific bit of the coded symbols includes at least one of a plurality of resource elements (REs) included in the physical channel, Wherein symbols corresponding to the remaining bits of the coded symbols, except for the at least one specific bit among the plurality of bits, are mapped to the second RE of the first RE and the at least one Wherein the plurality of REs are mapped to the other REs except for the second RE, and the plurality of REs have different time and frequency indices. 17. The method of claim 16, Wherein the at least one specific bit includes a Most Significant Bit (MSB) among the plurality of bits. 17. The method of claim 16, Wherein the at least one specific bit indicates one of ACK (acknowledgment) information and NACK (Negative ACK) information. 17. The method of claim 16, And the remaining bits are sequentially mapped to the remaining REs or are mapped randomly to the remaining REs. 17. The method of claim 16, The at least one specific bit may include at least one of a plurality of pilot symbols located between an RE to which a first pilot symbol is mapped and an RE to which a second pilot symbol is mapped among the plurality of pilot symbols, Wherein the at least one third RE is mapped to one third RE and the at least one third RE indicates at least one RE that is the farthest in distance from the first pilot symbol and the second pilot symbol.

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