WO2012039556A2

WO2012039556A2 - Apparatus and method for transmitting downlink control information in a wireless communication system

Info

Publication number: WO2012039556A2
Application number: PCT/KR2011/006590
Authority: WO
Inventors: 홍성권; 박경민
Original assignee: 주식회사 팬택
Priority date: 2010-09-20
Filing date: 2011-09-07
Publication date: 2012-03-29
Also published as: WO2012039556A3; KR20120030819A

Abstract

Provided is an apparatus and method for transmitting downlink control information in a wireless communication system. According to the present disclosure, the method comprises the steps of: configuring a hybrid field including any or both of main control information and sub control information; configuring downlink control information including the hybrid field; transmitting the downlink control information to a terminal; and receiving uplink information from the terminal on the basis of the downlink control information. According to the present invention, new control information can be added while maintaining the existing DCI format, thereby providing compatibility with existing systems without increasing the complexity of blind decoding.

Description

Apparatus and method for transmitting downlink control information in wireless communication system

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting downlink control information in a wireless communication system.

Data or various uplink control information is transmitted through an uplink control channel. The uplink control signal includes an acknowledgment (ACK) / not-acknowledgement (NACK) signal for performing a hybrid automatic repeat request (HARQ), a channel quality indicator (CQI) indicating downlink channel quality, a precoding matrix index (PMI), There are various types such as RI (Rank Indicator).

Downlink control information must be added to deal with other new procedures or new information required with the emergence of a new system. To do this, keep the format compatible with the existing system, but consider adding new fields. However, the format of the existing downlink control information is very limited, and there is little room for adding a new field. In addition, even if a new field is added, this causes a problem of a burden of blind decoding of the UE. Therefore, even if new downlink control information to be applied to a new system is added, there is a need for an apparatus and a method for transmitting downlink control information to minimize and change the structure of an existing system.

An object of the present invention is to provide an apparatus and method for transmitting downlink control information in a wireless communication system.

Another object of the present invention is to provide a method of configuring an existing format of downlink control information into a format of new downlink control information.

Another technical problem of the present invention is to provide a method for constructing a mixed field.

According to an aspect of the present invention, a method for transmitting downlink control information is provided. The method may optionally include any one of main control information and sub control information, or construct a hybrid field including both the main control information and the sub control information, and including the mixed field. Configuring downlink control information, transmitting the downlink control information to a terminal, and receiving uplink information from the terminal based on the downlink control information.

A first code point group among all code points indicated by the mixed field is mapped to the main control information, and a second code point group is mapped to the sub control information.

According to another aspect of the present invention, a method of receiving downlink control information is provided. The method includes selectively receiving any one of main control information and sub control information, or receiving downlink control information including a mixed field including both the main control information and the sub control information from a base station, and And transmitting uplink information to the base station based on the downlink control information.

According to another aspect of the present invention, there is provided a base station for transmitting downlink control information. The base station optionally includes any one of the main control information and the sub-control information, or a mixed field configuration unit constituting a mixed field including both the main control information and the sub-control information, the downlink including the mixed field A downlink control information constructing unit constituting link control information, a transmitting unit for transmitting the downlink control information to a terminal, and a receiving unit for receiving uplink information from the terminal based on the downlink control information.

The mixed field constructing unit maps a first code point group among all code points indicated by the mixed field to the main control information, and maps a second code point group to the sub control information.

According to another aspect of the present invention, a terminal for receiving downlink control information is provided. The terminal includes a receiving unit for selectively including any one of the main control information or sub-control information, or receiving downlink control information from the base station including a mixed field including both the main control information and the sub-control information, the And a downlink control information analyzer for analyzing the format of the downlink control information, a data generator for generating uplink information based on the analysis, and a data transmitter for transmitting the generated data.

The downlink control information analyzing unit analyzes the downlink control information by a first method when the mixed field includes the main control information, and the downlink control when the mixed field includes the sub control information. The information is interpreted in a second manner.

New control information can be added while maintaining the existing DCI format, providing compatibility with existing systems without increasing the complexity of blind decoding.

1 shows a wireless communication system.

2 shows the structure of a radio frame in 3GPP Long Term Evolution (LTE).

3 shows a structure of a downlink subframe.

4 is an explanatory diagram showing control information mapped to code points of a mixed field according to an embodiment of the present invention.

5 is a flowchart illustrating a method of transmitting DCI including a mixed field according to an embodiment of the present invention.

6 is a flowchart illustrating a method of transmitting downlink control information of a base station according to an embodiment of the present invention.

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

8 is a block diagram illustrating a base station and a terminal according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

In addition, in describing the component of this specification, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but between components It will be understood that may be "connected", "coupled" or "connected".

In addition, the present specification describes a wireless communication network, the operation performed in the wireless communication network is performed in the process of controlling the network and transmitting data in the system (for example, the base station) that is in charge of the wireless communication network, or the corresponding wireless Work may be done at the terminal coupled to the network.

According to embodiments of the present invention, 'transmitting a channel' may be interpreted as meaning transmitting information through a specific channel. Here, the channel is a concept including both a control channel and a data channel, and the control channel may be, for example, a physical downlink control channel (PDCCH) or a physical uplink control channel (PUCCH). The data channel may be, for example, a Physical Downlink Shared CHannel (PDSCH) or a Physical Uplink Shared CHannel (PUSCH).

1 shows a wireless communication system.

Referring to FIG. 1, the wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data. The wireless communication system 10 includes at least one base station (BS) 11. Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c. The cell can in turn be divided into a number of regions (called sectors).

The mobile station (MS) 12 may be fixed or mobile, and may include a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a PDA. (personal digital assistant), wireless modem (wireless modem), a handheld device (handheld device) may be called other terms. The base station 11 generally refers to a fixed station communicating with the terminal 12, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, an femto base station (femto BS), It may be called other terms such as relay, transmission point.

Cells

15a, 15b, and 15c should be interpreted in a comprehensive sense indicating some areas covered by the base station 11, and encompass all of the various coverage areas such as megacells, macrocells, microcells, picocells, and femtocells. to be.

In the following, downlink means communication from the base station 11 to the terminal 12, and uplink means communication from the terminal 12 to the base station 11. In downlink, the transmitter may be part of the base station 11 and the receiver may be part of the terminal 12. In uplink, the transmitter may be part of the terminal 12 and the receiver may be part of the base station 11. There is no limitation on the multiple access scheme applied to the wireless communication system. Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), OFDM-FDMA, OFDM-TDMA For example, various multiple access schemes such as OFDM-CDMA may be used. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

2 shows the structure of a radio frame in 3GPP Long Term Evolution (LTE).

Referring to FIG. 2, a radio frame includes 10 subframes, and one subframe includes two slots. The time it takes for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms and one slot may have a length of 0.5 ms.

One slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and includes a plurality of resource blocks (RBs) in the frequency domain. The OFDM symbol is for representing one symbol period and may be called an SC-FDMA symbol or a symbol period according to a multiple access scheme. The RB includes a plurality of consecutive subcarriers in one slot in resource allocation units.

The structure of the radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe and the number of OFDM symbols included in the slot may be variously changed.

3 shows a structure of a downlink subframe.

Referring to FIG. 3, a subframe includes two slots. Up to three OFDM symbols in the first slot of the subframe are control regions to which control channels are allocated, and the remaining OFDM symbols are data regions to which a Physical Downlink Shared Channel (PDSCH) is allocated.

The downlink control channel includes a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid-ARQ indicator channel (PHICH), and the like. The PCFICH transmitted in the first OFDM symbol of the subframe carries information about the number of OFDM symbols (that is, the size of the control region) used for transmission of control channels in the subframe. The PHICH carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for an uplink HARQ (Hybrid Automatic Repeat Request). That is, the ACK / NACK signal for the uplink data transmitted by the terminal is transmitted on the PHICH.

PDCCH is a resource allocation and transmission format of downlink shared channel (DL-SCH), resource allocation information of uplink shared channel (UL-SCH), paging information on PCH, system information on DL-SCH, random access response transmitted on PDSCH Resource allocation of a higher layer control message, a set of transmission power control commands for individual UEs in an arbitrary UE group, and activation of a Voice over Internet Protocol (VoIP). A plurality of PDCCHs may be transmitted in the control region, and the terminal may monitor the plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or several consecutive control channel elements (CCEs), which is a logical allocation unit used to provide a PDCCH with a coding rate according to the state of a radio channel. The CCE corresponds to a plurality of resource element groups The format of the PDCCH and the number of bits of the PDCCH are determined according to a correlation between the number of CCEs and the coding rate provided by the CCEs.

Control information transmitted through the PDCCH is referred to as downlink control information (DCI). DCI has different uses according to its format, and fields defined in DCI are also different. Table 1 shows DCI according to DCI format.

Table 1

DCI format	Explanation
0	Used for scheduling of PUSCH (Uplink Grant)
One	Used for scheduling one PDSCH codeword
1A	Used for simple scheduling of one PDSCH codeword and a random access procedure initiated by a PDCCH command
1B	Used for simple scheduling of one PDSCH codeword using precoding information
1C	Used for brief scheduling of one PDSCH codeword and notification of MCCH changes
1D	Used for simple scheduling of one PDSCH codeword containing precoding and power offset information
2	Used for PDSCH scheduling for UE configured in spatial multiplexing mode
2A	Used for PDSCH scheduling of UE configured in long delay CDD mode
3	Used to transmit TPC commands for PUCCH and PUSCH with power adjustment of 2 bits
3A	Used to transmit TPC commands for PUCCH and PUSCH with single bit power adjustment

DCI format 0 indicates uplink resource allocation information, DCI formats 1 to 2 indicate downlink resource allocation information, and DCI formats 3 and 3A indicate uplink transmit power control (TPC) commands for arbitrary UE groups. . Each field of the DCI is sequentially mapped to an information bit. For example, if DCI is mapped to information bits having a total length of 44 bits, the resource allocation field may be mapped to 10th to 23rd bits of the information bits.

DCI includes uplink resource allocation information and downlink resource allocation information. The uplink resource allocation information may be referred to as an uplink grant, and the downlink resource allocation information may be referred to as a downlink grant.

Table 2 shows fields included in an uplink grant according to an embodiment of the present invention.

TABLE 2

The flag is an indicator for distinguishing DCI 0 from DCI 1A as 1-bit information. The hopping flag is 1-bit information and indicates whether frequency hopping is applied or not when the terminal performs uplink transmission. For example, if the hopping flag is 1, frequency hopping is applied during uplink transmission, and if hopping flag is 0, frequency hopping is not applied during uplink transmission.

Resource block assignment and hopping resource allocation is also called a resource allocation field. The resource allocation field indicates the physical location or amount of resources allocated to the terminal. Although not shown in Table 2, the uplink grant includes a surplus bit or a padding bit to keep the total number of bits constant. There are various formats of DCI. Even if the control information of the different formats is used by using the surplus bits, the length of the bits can be adjusted to be the same, and thus, the UE can smoothly perform blind decoding.

For example, in Table 2, if the resource allocation field is 13 bits in the FDD 20MHz band, the uplink grant is 27 bits (excluding the CIF field and the CRC field). If the length of the bit determined as the blind decoding input is 28 bits, the base station adds an extra bit of 1 bit to the uplink grant during scheduling so that the total number of bits of the uplink grant is 28 bits. At this time, since the surplus bits do not contain special information, all of them may be set to zero. Of course, the number of surplus bits may be less than two, or may be large.

In this way, the purpose of the DCI is determined by its format, and the type of the field included in the DCI is also determined by the format. As the structure of the system evolves, the amount of existing control information may increase or new control information may be required. In this case, adding a new field other than the existing field in the DCI will eventually change the DCI format. This increases the complexity of blind decoding, which is a process of extracting the DCI format from the physical downlink control channel (PDCCH). In blind decoding, in a specific transmission mode, the UE decodes all possible DCI formats from the decoding start point defined in the region of the PDCCH. At this time, the user is distinguished from the Cell-Radio Network Temporary Identifier (C-RNTI) masked in the CRC. The complexity of blind decoding increases with the number of DCI formats to be decoded. The difference in DCI size means that the number of DCI formats to be decoded increases.

Therefore, even when adding new control information or control channel, it is desirable to maintain the existing DCI format. As an embodiment, a method of configuring a field itself, which is not used in the existing DCI format, with new control information may be considered. For example, in DCI format 0, a redundant bit exists for 1 bit for each band. To configure DCI format 0 and DCI format 1A in the same format, these extra bits must be added to match each other. The surplus bits may be used to distinguish whether resource allocation is non-contiguous resource allocation (RA) or contiguous resource allocation. Most of these extra bits do not exist in other DCI formats. Therefore, a method of configuring a field which is not used previously with new control information is very limited.

In another embodiment, a hybrid field, which is a field corresponding to two types of control information, is provided in the DCI. According to this, even if new control information is added, the existing DCI format can be maintained, thereby providing compatibility with the existing system without increasing the complexity of blind decoding.

Hereinafter, a method of configuring a control channel for adding new control information while maintaining DCI format 0 will be described. Since DCI formats vary, the types of fields that are the target of the mixed field also vary. In the present invention, the mixed field will be described based on DCI format 0. However, this is for convenience of description only and does not limit the technical spirit of the present invention. The mixed field according to the present invention is DCI format 0/1 / 1A /. Of course, it can be applied to all cases such as 1B / 1C / 1D / 2 / 2A / 3 / 3A.

The mixed field corresponds to primary control information or secondary control information. Alternatively, the mixed field corresponds to the main control information and the sub control information. For example, the primary control information is uplink MCS-related information, and the secondary control information is information related to transmission of an aperiodic sounding reference signal. Alternatively, the mixed field may correspond to two or more types of control information. With only one mixed field, various kinds of control information can be contained in DCI.

The number of bits of the mixed field is predefined in the DCI format including the mixed field. For example, the number of bits of the mixed field may be predefined as 3 bits, 5 bits, or the like. The number of bits of the mixed field determines the number of cases that the mixed field can represent. For example, if the number of bits of the mixed field is 2 bits, the number of cases that the mixed field can represent is 2 ² = 4 in total. The number of cases each mixed field can represent is called a code point. As the number of bits in the mixed field increases, the number of code points increases.

One code point represents one state of control information corresponding to a mixed field. For example, when a mixed field has 2 bits and a total of 4 code points, each code point may be mapped to one state of control information such as a modulation and coding scheme (MCS) as shown in the following table.

TABLE 3

Mixed field (2 bits)	Sign point	One state of control information (MCS level)
00	0	BPSK
01	One	QPSK
10	2	8PSK
11	3	16QAM

Referring to Table 3, code point 0 represented by mixed field 00 is mapped to one state of MCS level called Binary Phase Shift Keying (BPSK). Similarly, code point 3 represented by mixed field 11 is mapped to one state of control information called 16QAM (Quadrature Amplitude Modulation).

Also, the code point of the mixed field may be mapped to main control information or sub-control information according to its range. For example, when 32 code points are used, 20 of them are mapped to main control information, and the remaining 12 are mapped to sub control information. This means that two control information can be defined by the mixed field.

Referring to FIG. 4, the mixed field is n bits, and the code points of the mixed field are 2n (0 to 2n-1) in total. Here, the code points 0 to 2k are mapped to the main control information, and the code points 2k + 1 to 2n-1 are mapped to the sub control information. In this way, the code point is divided into two groups, the first code point group is used to express the main control information, and the second code point group is used to represent the sub control information. Information can be represented. The main control information and the sub control information are defined in terms of the code point as follows. The main control information is control information in which the number of usable code points is limited by higher layer signaling or a constraint condition arbitrarily applied by the system. The sub control information is control information mapped to the code point of the main control information remaining due to the constraint applied to the main control information.

Hereinafter, the main control information corresponding to the mixed field will be described. One example of the main control information is Modulation and Coding Scheme and Redundancy Version information (MCS) / RV information (hereinafter referred to as modulation surplus information). The modulation and coding method indicates a modulation order and coding transmitted in uplink. The surplus index indicates a version used for retransmission of data in HARQ (Hybrid Automatic Repeat reQuest).

Table 4 shows main control information according to an embodiment of the present invention.

Table 4

Referring to Table 4, a total of 32 code points (0 to 31) regarding modulation surplus information are provided. Q ' _m represents a modulation order, I _TBS represents a size index of a transport block, and rv _idx represents a surplus index. Thereafter, the embodiment represented by I _TBS can equally be applied to an embodiment alternative to the transport block size _TBS I. Each code point is mapped to one state or MCS index I _MCS of modulation surplus information. For example, the code point 10 is mapped to the modulation surplus information in a state where the modulation order is 2, the size index of the transport block is 10, and the surplus index is zero.

When the modulation order (Q _'m) 2 is QPSK, if the modulation order 4 16QAM, the modulation order of 6 denotes 64QAM. The size of an uplink allocated by an uplink grant according to DCI format 0 is determined by a combination of N _PRBs determined by an I _TBS and a resource allocation field. rv _idx indicates a relative overlap with respect to the first transport block when the allocated uplink grant block is a retransmission block.

The rules for determining the modulation order and surplus index are as follows.

For 0 ≤ code point ≤ 28, the modulation order is determined as follows. i) If the UE supports 64QAM in PUSCH and is not determined to transmit only QPSK and 16QAM in the upper layer, the modulation order is given in Table 4 above. ii) If the UE does not support 64QAM in the PUSCH or it is determined to transmit only QPSK and 16QAM in the upper layer, the modulation order is Q'm = min (4, Q ' _m ) using the modulation order obtained in Table 4 above. Obtained from. iii) If the TTI bundling coefficient provided by the upper layer is set to TRUE, the resource allocation size is limited to N _PRB ≤ 3 and the modulation order is set to 2.

For 29≤code≤≤31, the modulation order is assumed to be the same as determined in the most recent PDCCH except for the following cases. If the code point = 29 and the "CQI Request" bit of DCI format 0 is set to 1 and N _PRB ≤ 4, then the modulation order is set to 2.

Hereinafter, the main control information and the sub control information corresponding to the mixed field will be described. In order to configure a control channel such as the existing DCI format 0, the base station applies a certain constraint by higher layer signaling or a separate control channel such as a Radio Resource Control (RRC) message or a Medium Access Control (MAC) message. Impose on control information. In addition, when the constraint is changed, a new code point group for main control information and sub-control information is generated according to the changed constraint as a new signaling or a separate control channel. First, the base station may assign the code point of the mixed field to the main control information to which the constraint is imposed. The base station may allocate the remaining code points mapped to the main control information to which the constraint is imposed, to the sub control information.

Table 5 shows main control information and sub control information according to another example of the present invention.

Table 5

Referring to Table 5, code points 0 to 20 are cases where modulation orders are 2 and 4, and code points 21 to 28 are cases where modulation orders are 6. Code points 0 to 20 and code points 29 to 31 are first group of code points and are used to display main control information (modulation surplus information). If the system imposes a constraint that the modulation order of 64QAM is not used, the code points 21 through 28 of modulation order 6 are not used as the main control information. Table 5 is the same as Table 1, except that the code points that are not used as the main control information due to the constraints are indicated by shading.

In Table 5, the coded points 21 to 28 indicated by the shade are the second code point group, and the second code point group includes a total of eight code points. Accordingly, the second code point group may represent three bits of sub-control information. If the system imposes a constraint not to use the modulation order of 16QAM, the second code point group is expanded to 11 to 28. Therefore, sub-control information can be expressed with a total of 18 code points.

Table 6 shows main control information and sub control information according to another embodiment of the present invention.

Table 6

Referring to Table 6, Table 6 is the same as Table 1, but code points that are not used as main control information are shaded. The

even code points

0, 2, 4, ..., 28 and the code points 29 to 31 are assigned to the main control information as the first code point group, and the

odd code points

1, 3, 5, ... 27 are The second code point group includes a total of 14 code points. The second code point group is allocated for transmission of the sub control information. In this way, among all code points of the mixed field, code points corresponding to a certain period (constant pattern) can be allocated to the main control information, and the rest can be allocated to the sub control information.

Table 7 shows main control information and sub control information according to another embodiment of the present invention.

TABLE 7

Referring to Table 7, Table 7 is the same as Table 1, but code points that are not used as main control information are shaded. The code points 22, 24, 26, 28 indicated by the shade are assigned to the sub control information as the second code point group, and the first code point group consisting of the remaining code points is assigned to the main control information. In this case, the code point is assigned to the main control information and the sub control information with a periodic pattern only for the modulation order of 64QAM. Since the second code point group includes four code points, two bits of sub-control information can be configured in the mixed field.

Table 8 shows main control information and sub control information according to another embodiment of the present invention.

Table 8

Table 8 is the same as Table 1, but the code points not used as the main control information are shown in shaded form. The shaded code points 11 and 21 are allocated to the sub control information as the second code point group, and the first code point group composed of the remaining code points is allocated to the main control information. In this case, even if the modulation order is different, only one of the code points having the same transport block size is allocated to the primary control information, and the other is allocated to the secondary control information. That is, the size of the transport block depends on the I _TBS , and some of the code points in the case where these values have the same case are selected and assigned to the sub-control information.

In Table 8, only one code point (e.g., one code point with a high modulation order) is controlled in the case of I _TBS = 10 and I _TBS = 19 having the same transport block size. It is restricted from assigning the information. Of course, a code point with a small modulation order may be limited. In this case, the cause of the performance degradation which can be caused by limiting the code point of the main control information can be largely eliminated.

Table 9 shows main control information and sub control information according to another embodiment of the present invention.

Table 9

Table 9 is the same as Table 1, but code points that are not used as main control information are shaded. The code points 11, 21, 26, and 27 indicated by the shade are allocated to the sub control information as the second code point group, and the first code point group composed of the remaining code points is allocated to the main control information. In the first constraint, as shown in Table 8, only one of the code points having the same transport block size is allocated to the main control information, and the other is allocated to the sub-control information even if the modulation order is different. That is, the size of the transport block depends on the I _TBS , and some of the code points in the case where these values have the same case are selected and assigned to the sub-control information. The additional second constraint is that the code points 26 and 27 are assigned to the sub control information with the limitation in the 64QAM modulation order, so that the 2-bit sub control information can be transmitted.

As shown in Tables 4 to 9, when the control condition is applied to the main control information (modulation surplus information) of the mixed field and the control channel for the sub control information is configured using the code point remaining by the restriction condition, the mixing The field may not contain the original main control information. In this case, in the configuration of the control channel for the sub control information, the main control information should be set to a specific state. As an example, the state of the main control information most recently transmitted to the same terminal is regarded as the state of the virtual main control information that should be set by the current base station and the terminal. For example, assume that the most recent modulation surplus information is code point = 10. If the terminal receives the mixed field including the sub-control information, the terminal assumes the code point 10, which is the most recent modulation surplus information, and performs uplink transmission based on QPSK and I _TBS = 10.

As another example, the operation is performed by viewing the state of the main control information corresponding to the specific code point of the second code point group as the current virtual main control information. For example, it is assumed in Table 8 that the sub-control information corresponding to the code point 11 of the mixed field is transmitted to the terminal by the base station. The mixed field does not contain main control information. Accordingly, the terminal assumes that the main control information is in a specific state and performs uplink transmission. In this case, when the mixed field includes the main control information, the terminal returns the main control information corresponding to the code point 11 to the specific state. Set it. In this case, QPSK and I _TBS = 10 having a modulation order of two. As another example, QPSK and I _TBS = 6 having a modulation order of 2 corresponding to the code point 6 may be set.

This setting of the main control information to a virtual specific state may be performed with a preference according to a mode and / or a specific rule in which the main control information is restricted, or may be determined by a higher layer and informed by signaling or a separate control channel. have.

In addition to the mixed field, additional code points may be provided in the sub control information. The additional code point is provided by another field in the DCI. The field providing this additional code point is called an additional field. When additional fields are used, additional code points may be provided to sub-control information, but the nature of the additional fields is lost. For example, if the additional field is a frequency hopping field, a constraint that does not apply frequency hopping may be applied. Thus, the bits of the frequency hopping field can be allocated to the sub control information. The surplus bits may also be allocated to the sub control information as additional fields. If the additional field is assigned to the sub control information, the original function of the additional field is lost, so that the control information related to the additional field may be set as a default. For example, if the additional field is a frequency hopping field, the additional field contains sub control information rather than information about frequency hopping. That is, since there is no information about frequency hopping, it can be promised that frequency hopping is applied or not applied between the base station and the terminal.

The constraints on the main control information are often not considered to be a factor that degrades the system performance considering the actual use of the control channel. For example, it is preferable to use a low order modulation order because the channel information is not sufficiently grasped. In such an environment, limiting the main control information does not bring about significant performance degradation.

Hereinafter, the sub control information will be described. The sub-control information includes information on setting an aperiodic sounding reference signal (hereinafter referred to as ASRS) (hereinafter referred to as ASRS setting information), information indicating triggering on / off of the aperiodic sounding reference signal, and channel state information ( Channel State Information (CSI) includes at least one of the information on the transmission configuration, the information on the ACK / NACK transmission configuration. If the mixed field indicates any code point of the second code point group, the terminal indicates that the DCI including the mixed field has sub-control information (for example, information on transmission setting of ASRS setting information or channel state information or Information on the ACK / NACK transmission setting).

The ASRS configuration information includes various fields necessary for the transmission of the ASRS as shown in Table 10.

Table 10

SRS Information Element	Number of bits	Contents
SRS activation	One	Interpreting the DCI Format
Transmission BW
	2	4 SRS Bandwidths per Operating Bandwidth
Frequency Position
	3 or 5	Start Bandwidth Location (3 bits for <= 5 MHz)
Transmission Comb	One	2 combs
SRS Cyclic Shift	3	8 cyclic shift
SRS Configuration Index I _SRS	9	Configuration of Subframes Assigned for SRS Transmission
Duration
	0	Same Duration or One-Shot Transmission
SRS Bandwidth Configuration	0	Configure via one shot or known SIB
CRC (UE ID)	16	UE ID masked in CRC
total	35 or 37

Referring to Table 10, the SRS Activation field is 1 bit information and indicates whether the corresponding DCI is a format related to transmission of the ASRS. The frequency position field is a parameter that determines the start position of an uplink bandwidth with respect to the ASRS. The Transmission Comb field is a parameter that defines an UpPTS section belonging to a special subframe in the TDD system. The SRS Configuration Index field is a parameter that determines the position and offset of a subframe in which the ASRS is transmitted. The cyclic shift field is a parameter for generating a sequence for transmission of the ASRS.

As another example of sub-control information, it may include triggering of channel state information (CSI) such as CQI / PMI, uplink component carrier transmitting CSI, or information of downlink component carrier targeted for CSI. . Even in this case, the mixed field may be combined with a carrier indicator format (CIF) or a CQI request field to express sub-control information.

Referring to FIG. 5, the base station transmits information about the mixed field to the terminal (S500). As an example, the information on the mixed field includes a mixed field indicator indicating whether the mixed field includes main control information, sub control information, or both. For example, the mixed field indicator may be 1 bit. If 0, the mixed field indicator may indicate that the mixed field includes main control information.

Alternatively, the information about the mixed field may include code point group information for distinguishing allocation modes of a first code point group and a second code point group among all code points of the mixed field. For example, the code point group information indicates which mode of Tables 4 to 9 is allocated to the first code point group and the second code point group.

The information about the mixed field may be any one of a message of a physical layer, a message of a MAC layer, and a message of an RRC layer.

If the first and second code point groups are previously regulated between the terminal and the base station, or if the terminal is already known, the base station does not need to separately transmit information about the mixed field. Therefore, in this case, step S500 can be omitted.

The base station configures a mixed field (S505). The hybrid field may include one or both of main control information and sub control information. The main control information may be modulation surplus information, and the sub control information may be information about an aperiodic sounding reference signal (ASRS). As described above, when a constraint is applied that restricts the case where the mixed field includes the main control information, the remaining second code point group which is not assigned as the main control information by the constraint is used as the sub control information.

The base station transmits downlink control information (DCI) including the mixed field to the terminal (S510). The downlink control information may be an uplink grant of DCI format 0. An example of the downlink control information is shown in Table 11 below.

Table 11

The terminal performs uplink transmission according to the main control information or the sub control information included in the downlink control information (S515). If the downlink control information includes main control information that is modulation surplus information, the terminal may generate uplink data according to the modulation order and the redundant version designated by the modulation surplus information and transmit the uplink data to the base station. On the other hand, if the downlink control information includes sub-control information which is ASRS-related information, the terminal may transmit a sounding reference signal to the base station at any time.

Referring to FIG. 6, the base station determines whether the downlink control information (DCI) to be transmitted is a new DCI format (S600). The new DCI format means that the mixed field of DCI is used for the purpose of sub-control information other than the existing main control information. If the downlink control information is a new DCI format, the base station configures a mixed field to which the constraint is applied (S605). Here, the constraint means a condition that restricts the use of some state of the main control information in the system. The presence of a constraint indicates that some code points are not used as code points for main control information. Therefore, the code point of the mixed field belongs to the second code point group.

The base station configures downlink control information including the mixed field (S610) and transmits it to the terminal (S615).

On the other hand, in step S600, if the downlink control information to be transmitted is not a new DCI format, the base station configures a mixed field as main control information according to the existing method (S620) and downlink including the mixed field. Configure the control information (S610), and transmits it to the terminal (S615).

Referring to FIG. 7, the terminal receives downlink control information (DCI) from the PDCCH (S700). This is received by the blind decoding process. The terminal determines whether the code point of the mixed field included in the downlink control information belongs to the second code point group (S705). Here, whether the code point of the mixed field belongs to the second code point group is determined using the information on the mixed field as in step S500 in FIG. If belonging to the second code point group of the code point of the mixed field, the terminal interprets the information of the mixed field as sub-control information (S710), and defaults the state of the main control information which is the original use of the mixed field. (default) or determined by a value determined by the rule (S715).

On the other hand, in step S705, if belonging to the second code point group, not the second code point group of the code point of the mixed field, the terminal interprets the information of the mixed field as the main control information (S720). .

Referring to FIG. 8, the terminal 800 includes an uplink grant receiver 805, a DCI analyzer 810, a data generator 815, and a data transmitter 820.

The uplink grant receiver 805 receives the uplink grant transmitted on the PDCCH by blind decoding. The uplink grant includes uplink scheduling parameters and mixed fields for uplink transmission.

The DCI analyzing unit 810 analyzes whether the mixed field included in the uplink grant includes the main control information or the sub control information. This analysis may be performed by signaling from the base station 850 or by a separate control channel, and the terminal directly determines whether the code point of the mixed field belongs to the first code point group or the second code point group. It may also be performed by. If the code point of the mixed field belongs to the first code point group, the DCI analysis unit 810 includes the main control information, and if the code point of the mixed field belongs to the second code point group, The mixed field may be interpreted as including sub control information.

The data generator 815 generates uplink information based on the main control information or the sub control information according to the result of the DCI analyzer 810. If the mixed field includes main control information that is modulation surplus information, the uplink information is uplink data according to a modulation order and a redundant version of the modulation surplus information. If the mixed field includes sub control information which is ASRS related information, the uplink information is a sounding reference signal that is generated aperiodically. The sub-control information, which is the ASRS-related information, includes triggering and sounding setting control information for the sounding reference signal.

The data transmitter 820 transmits uplink information generated by the data generator 815 to the base station 850.

The base station 850 includes a mixed field configuration unit 855, a scheduling unit 860, an uplink grant transmitter 865, and a data receiver 870.

The mixed field construction unit 855 constitutes a mixed field. The mixed field may include one or both of main control information and sub control information. The main control information may be modulation surplus information, and the sub control information may be information about an aperiodic sounding reference signal (ASRS). As described above, when a constraint is applied that restricts the case where the mixed field includes the main control information, the remaining second code point group which is not assigned as the main control information by the constraint is used as the sub control information.

The scheduling unit 860 sets uplink scheduling parameters based on the mixed field configured by the mixed field constructing unit 855. The uplink scheduling parameter is a parameter for generating information as shown in Table 11 above.

The uplink grant transmitter 865 generates an uplink grant including a mixed field by using an uplink scheduling parameter set by the scheduling unit 860, and transmits the uplink grant to the terminal 800.

The data receiver 870 receives uplink data or an ASRS from the terminal 800. When the data receiver 870 receives the ASRS from the terminal 800, the data receiver 870 may send information about the ASRS to the scheduling unit 860 (not shown). In this regard, the scheduling unit 860 may estimate an uplink channel based on the information on the ASRS, and set an uplink scheduling parameter according to the estimation result.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

In the method of transmitting downlink control information,

Selectively including any one of main control information and sub control information, or constructing a hybrid field including both the main control information and the sub control information;

Constructing downlink control information including the mixed field;

Transmitting the downlink control information to a terminal; And

Receiving uplink information from the terminal based on the downlink control information,

Downlink control, characterized in that the first code point group of all code points indicated by the mixed field is mapped to the main control information, the second code point group is mapped to the sub-control information How information is sent.
The method of claim 1,

The sub control information is information indicating that triggering aperiodic transmission of a sounding reference signal (SRS), which is a reference signal for measuring a state of an uplink channel, is downlink. Transmission method of link control information.
The method of claim 1,

The downlink control information is an uplink grant, which is allocation information about uplink transmission of the user equipment.
The method of claim 1,

The main control information is information indicating at least one of a modulation order of the uplink information, a size of a transport block, and a redundancy version. How information is sent.
The method of claim 1,

And transmitting information about a mixed field indicating whether the mixed field includes one of the main control information and the sub control information to the terminal.
The method of claim 1,

And the second code point group includes code points which are not limited when the mixed field is not used as the main control information.
In the method for receiving downlink control information,

Selectively receiving any one of main control information and sub control information, or receiving downlink control information including a mixed field including both the main control information and the sub control information from a base station; And

Transmitting uplink information to the base station based on the downlink control information;

A first code point group among all code points indicated by the mixed field is mapped to the main control information, and a second code point group is mapped to the sub control information.
The method of claim 7, wherein

The sub-control information is information indicating that triggers aperiodic transmission of a sounding reference signal, which is a reference signal for measuring a state of an uplink channel, characterized in that the downlink control information.
The method of claim 7, wherein

The downlink control information is an uplink grant which is allocation information regarding uplink transmission of the terminal.
The method of claim 7, wherein

The main control information is information indicating at least one of the modulation order of the uplink information, the size of a transport block, the redundant version, the method of receiving downlink control information.
The method of claim 7, wherein

And receiving, from the base station, information about the mixed field indicating whether the mixed field includes the main control information or the sub control information.
The method of claim 7, wherein

And the second code point group includes code points which are not limited when the mixed field is restricted so as not to be used as the main control information.
In the base station for transmitting downlink control information,

A mixed field constructing unit selectively including any one of main control information and sub control information, or composing a mixed field including both the main control information and the sub control information;

A downlink control information constructing unit constituting downlink control information including the mixed field;

A transmitter for transmitting the downlink control information to a terminal; And

Includes a receiving unit for receiving uplink information from the terminal based on the downlink control information,

And the mixed field constructing unit maps a first code point group among all code points indicated by the mixed field to the main control information, and maps a second code point group to the sub control information.
In a terminal for receiving downlink control information,

A receiving unit for selectively including any one of main control information and sub control information, or receiving downlink control information including a mixed field including both the main control information and the sub control information from a base station;

A downlink control information analyzer for analyzing a format of the downlink control information;

A data generator for generating uplink information based on the interpretation; And

Including a data transmission unit for transmitting the generated data,

The downlink control information analyzing unit analyzes the downlink control information according to a first scheme when the mixed field includes the main control information, and the downlink control when the mixed field includes the sub control information. Characterized in that the information is interpreted in a second manner.