WO2013002471A1

WO2013002471A1 - Method and apparatus for transmitting and receiving downlink control information in a wireless communication system

Info

Publication number: WO2013002471A1
Application number: PCT/KR2012/001253
Authority: WO
Inventors: 최혜영; 한승희; 김진민
Original assignee: 엘지전자 주식회사
Priority date: 2011-06-29
Filing date: 2012-02-20
Publication date: 2013-01-03

Abstract

The present invention relates to a wireless communication system, and more particularly, discloses a method of receiving control information by a terminal in a wireless communication system, including: determining a searching space formed of Physical Downlink Control Channel(PDCCH)candidates in a sub-frame from a base station; and attempt to decode each of the PDCCH candidates in the searching space. The searching space in which the attempting to decode is performed is determined by factors including a set level corresponding to a number of control channel elements (CCE) included in each of the PDCCH candidates, and a number of the PDCCH candidates according to the set level and a predetermined offset.

Description

【Specification】

[Name of invention]

Method and apparatus for transmitting and receiving downlink control information in wireless communication system

The following description relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving downlink control information in a wireless communication system supporting one or more serving cells.

Background Art

Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (0FDMA) systems, and SC-FDMAC single carrier frequency. division multiple access (MCD) system, and MC ᅳ FDMA Gult i carrier frequency division multiple access (MCD) system.

[Detailed Description of the Invention]

Technical problem The present invention is to reduce the number of times the terminal performs the blind decoding It is a task.

Technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following description. Could be.

Technical Solution

A first technical aspect of the present invention is a method of receiving control information from a terminal in a wireless communication system, the method comprising: determining a search space consisting of physical downlink control channel (PDCCH) candidates on a subframe from a base station; And attempting to decode each of the PDCCH candidates in the search space, wherein the search space in which the decoding is attempted corresponds to the number of control channel elements (CCEs) included in each of the PDCCH candidates. Provided is a control information receiving method, which is determined by factors including a set level, a number of PDCCH candidates and a predetermined offset according to the set level.

According to a second aspect of the present invention, there is provided a method of transmitting control information by a base station in a wireless communication system, the method comprising: determining a search space consisting of physical downlink control channel (PDCCH) candidates on a downlink subframe; And transmitting the control information through one PDCCH among the PDCCH candidates in the search space, wherein the search space includes a control channel element (CCE) included in each of the PDCCH candidates. Collection level based on the number, the collection It is to provide a control information transmission method, which is determined by factors including a number of PDCCH candidates and a predetermined offset according to a bell.

Technical aspect of the present invention provides an apparatus for receiving control information in a wireless communication system, comprising: receiving modules; And a processor, wherein the processor determines a search space consisting of physical downlink control channel (PDCCH) candidates, attempts to decode each of the PDCCH candidates on the search space, and the search space in which the decoding is attempted is performed. And a device level determined by factors including a number of control channel elements (CCEs) included in each of the PDCCH candidates, a number of PDCCH candidates according to the set level, and a predetermined predetermined offset. To provide.

A fourth technical aspect of the present invention is an apparatus for transmitting control information in a wireless communication system, comprising: transmission modules; And a processor, wherein the processor determines a search space consisting of physical downlink control channel (PDCCH) candidates on a downlink subframe, and wherein the control information is transmitted through a PDCCH of any one of the PDCCH candidates on the search space. The search space is controlled to be transmitted, and the search space includes a set level corresponding to the number of control channel elements (CCEs) included in each of the PDCCH candidates, a number of PDCCH candidates according to the set level, and a predetermined predetermined offset. To provide a device, as determined by the factors involved.

In the first to fourth technical aspects of the present invention, the search space is the predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal. One or more PDCCH candidates corresponding to the moved CCE number may be determined.

The search space may be determined by one or more PDCCH candidates corresponding to the CCE number shifted by the predetermined offset from the CCE number determined by the subframe number and the identifier of the UE.

The search space may be determined by one or more PDCCH candidates including a CCE corresponding to an integer multiple of the predetermined offset from the CCE number determined by the subframe number and the identifier of the UE.

The predetermined offset may be reset in consideration of the aggregation level.

The predetermined offset may be reset to a smaller value of a value obtained by multiplying the predetermined offset by the set level and the number of CCEs corresponding to the search space when the predetermined offset is not applied at the set level.

The predetermined offset may be reset to be proportional to the number of CCEs corresponding to the search space when the predetermined offset is not applied.

The predetermined offset may include a quotient obtained by dividing the number of CCEs corresponding to the search space when the predetermined offset is not applied by the predetermined offset and the number of CCEs corresponding to the search space when the predetermined offset is not applied. It may be reset to a small value.

In addition, the predetermined offset is, of the subframe received before the subframe It may be determined from any one of the control information and higher trade-off signaling.

Advantageous Effects

According to the present invention, the number of blind decoding can be reduced, thereby reducing the processing burden of the terminal.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

[Brief Description of Drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings appended hereto are for the purpose of providing an understanding of the invention and to illustrate various embodiments of the invention and to explain the principles of the invention in conjunction with the description of the specification.

1 is a diagram illustrating a structure of a radio frame used in a 3GPP LTE system. 2 is a diagram illustrating a resource grid in a downlink slot. 3 is a diagram illustrating a structure of an uplink subframe.

4 is a diagram illustrating a structure of a downlink subframe.

5 is a diagram illustrating a terminal specific search space at each aggregation level.

6 is a diagram for explaining carrier aggregation.

7 is a diagram for describing cross carrier scheduling.

8 and 9 are diagrams for describing a method that can be used when exchanging scheduling information between respective base stations. 10 is a diagram illustrating time-frequency resources allocated for ePDCCH.

FIG. 11 is a diagram for explaining that a search space is limited by using a relative offset.

12 is a view for explaining that the search space is limited by using an offset that is an absolute value.

FIG. 13 is a diagram illustrating that search space is limited to corresponding PDCCH candidates while skipping by an offset.

14 is a diagram illustrating a bitmap configuration for reducing the number of blind decoding.

15 is a diagram illustrating another configuration of a bitmap for reducing the number of blind decoding.

FIG. 16 is a diagram illustrating another configuration of a bitmap for reducing the number of blind decoding.

17 is a flowchart illustrating an exemplary PDCCH transmission / reception method of the present invention. 18 is a diagram showing the configuration of a preferred embodiment of a base station apparatus or a terminal apparatus according to the present invention.

[Best form for implementation of the invention]

The following embodiments combine the components and features of the present invention in a predetermined form. Each component or feature may be considered optional unless stated otherwise. Each component or feature may be combined with other components or features It may be carried out in a form that is not. In addition, some components and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of one embodiment may be included in another embodiment, or may be replaced with other configurations or features of another embodiment.

In the present specification, embodiments of the present invention will be described based on a relationship between data transmission and reception between a base station and a terminal. Here, the base station has a meaning as a terminal node of a network that directly communicates with the terminal. Certain operations described in this document as being performed by a base station may be performed by an upper node of a base station in some cases.

That is, it is apparent that various operations performed for communication with the terminal in a network consisting of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A 'base station (BS)' may be replaced by terms such as a fixed station, a Node B, an eNode B (e B), an access point (AP), and the like. In addition, in this document, the term base station may be used as a concept including a cell or a sector. On the other hand, the repeater may be replaced by terms such as Relay Node (RN), Relay Station (RS). The term 'terminal' may be replaced with terms such as UE user equipment (MS), mobile station (MS), mobile subscriber station (MSS), and subscriber station (SS). Certain terms used in the following description are provided to assist in understanding the present invention. The use of the specific terminology may be modified in other forms without departing from the technical spirit of the present invention.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of IEEE 802 systems, 3GPP systems, 3GPP LTE and LTE-Advanced (LTE-A) systems, and 3GPP2 systems, which are wireless access systems. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in this document may be described by the above standard document.

The following techniques are CDM Code Division Multiple Access (FDMA), FDMA (Frequency)

Division Multiple Access (TDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (0FDMA), SC_FDMA (Single

It can be used in various radio access systems such as Carrier Frequency Division Multiple Access. CDMA is UTRA Jni versa 1 Terrestrial Radio Access)

It may be implemented by a radio technology such as CDMA2000. TDMA

Wireless technologies such as GSMC Global System for Mobile communications (GPRS) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE) Can be manifested. 0FDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), or the like. UTRA is part of the UMTSCUniversal Mobile TelecxMiimunications System. 3rd Generation Partnership Project (3GPP) LTE term term evolution (3GPP) is a part of Evolved UMTS (E-UMTS) that uses E-UTRA, and employs 0FDMA in downlink and SC-FDMA in uplink. LTE-M Advanced) is the evolution of 3GPP LTE. WiMAX can be described by the IEEE 802.16e standard OVirelessMAN—OFDMA Reference System) and the advanced IEEE 802.16m standard (WirelessMAN-OFDMA Advanced system). For clarity, the following description focuses on 3GPP LTE and 3GPP LTE-A systems, but the technical spirit of the present invention is not limited thereto. Wireless frame

1 (a) is a diagram showing the structure of a radio frame used in the 3GPP LTE system. One radio frame includes 10 subframes, and one subframe includes two slots in the time domain. The time for transmitting one subframe is defined as a Transmission Time Interval (ΓΠ). For example, one subframe may have a length of lms, and one slot may have a length of 0.5 ms. One slot may include a plurality of 0FDM symbols in the time domain. Since the 3GPP LTE system uses the 0FDMA scheme in the downlink, the 0FDM symbol represents one symbol length (period). One symbol in the uplink It may be referred to as an SC-FDMA symbol or a symbol length. A resource block (RB) is a resource allocation unit and includes a plurality of consecutive subcarriers in one slot. The structure of such a radio frame is merely exemplary. Accordingly, the number of subframes included in one radio frame, the number of slots included in one subframe, or the number of OFDM symbols included in one slot may be changed in various ways.

Kb) illustrates the structure of a type 2 radio frame. Type 2 radio frames consist of two half frames. Each half frame consists of five subframes, a down link pilot time slot (DwPTS), a guard period (GP), and an upPTSCUplink pilot time slot (1), of which one subframe consists of two slots. do. The DwPTS is used for initial cell search, synchronization or channel estimation at the terminal. UpPTS is used for channel estimation at the base station and synchronization of uplink transmission of the terminal. The guard period is a period for removing interference caused in the uplink due to the multipath delay of the downlink signal between the uplink and the downlink. The structure of the radio frame is merely 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 symbols included in the slot may be variously changed. Slot structure

2 illustrates a resource grid in a downlink slot Cotton. One downlink slot includes seven OFDM symbols in the time domain and one resource block (RB) is illustrated as including 12 subcarriers in the frequency domain, but the present invention is not limited thereto. For example, in the case of a general cyclic prefix (CP), one slot includes 7 OFDM symbols, but in the case of an extended CP, one slot may include 6 OFDM symbols. Each element on the resource grid is called a resource element (RE). One resource block includes 12 X 7 resource elements. The number of NDLs of resource blocks included in the downlink slot depends on the downlink transmission bandwidth. The structure of the uplink slot may be the same as the structure of the downlink slot. UL subframe structure

3 is a diagram illustrating a structure of an uplink subframe. The uplink subframe may be divided into a control region and a data region in the frequency domain. A physical uplink control channel (PUCCH) including uplink control information is allocated to the control region. In the data area, a physical uplink shared channel (PUSCH) including user data is allocated. In order to maintain a single carrier characteristic, one UE does not simultaneously transmit a PUCCH and a PUSCH. PUCCH for one UE is allocated to an RB pair in a subframe. Resource blocks belonging to a resource block pair occupy different subcarriers for two slots. The RB pair allocated to the PUCCH is allocated to the slot boundary. It is said to be frequency-hopped. Downlink Subframe Structure

4 is a diagram illustrating a structure of a downlink subframe. Up to four OFDM symbols in front of the first slot in one subframe correspond to a control region to which a control channel is allocated. The remaining OFDM symbols correspond to data regions to which a physical downlink shared channel (PDSCH) is allocated. The downlink control channels used in the 3GPP LTE system include, for example, a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical HARQ offset channel. (Physical Hybrid automatic repeat request Indicator Channel, PHICH).

The PCFICH is transmitted in the first OFDM symbol of a subframe and includes information on the number of OFDM symbols used for control channel transmission in the subframe. The PHICH includes a HARQ ACK / NACK signal as a response of uplink transmission. The PDCCH includes uplink or downlink scheduling information and power control information. Downlink Control Information

Looking at the PDCCH in more detail, the control information transmitted through the PDCCH is called downlink control information (DCI). DCI Awards It includes uplink or downlink scheduling information or an uplink transmission power control command for a certain terminal group. The PDCCH is a resource allocation and transmission format of the downlink shared channel (DL-SCH), resource allocation information of the uplink shared channel (UL-SCH), paging information of the paging channel (PCH), system information on the DL-SCH, PDSCH Resource allocation of upper layer control messages, such as random access responses transmitted over a network, a set of transmit power control commands for individual terminals in a group of terminals, and transmission power control information of Voice over IP (VoIP) Activation and the like.

Different control information as described above has different DCI sizes. Currently, according to LTE-A (release 10), DCI formats 0, 1, 1A, IB, 1C, ID, 2, 2A, 2B, 2C, 3, 3A, and 4 are defined. In this case, DCI formats 0, 1A, 3, and 3A are defined to have the same message size in order to reduce the number of blind decoding times to be described later. These DCI formats are based on the purpose of the control information to be transmitted: i) DCI formats 0, 4, and ii) DCI formats 1, 1A, IB, 1C, ID, 2, 2A, 2B, 2C, and iii) DCI formats 3 and 3A for power control commands.

In the case of DCI format 0 used for uplink scheduling grant, a carrier indicator necessary for carrier aggregation to be described later, an offset used to distinguish DCI formats 0 and 1A (flag for format 0 / format 1A differentiation), A frequency hopping flag indicating whether frequency hopping is used in uplink PUSCH transmissions, and the resource block allocation to be used by the UE for PUSCH transmission. Resource block assignment, modulation and coding schemes, new data indicators used to empty the buffer for initial transmission in relation to HARQ processes, and transmit power for PUSCH TPC command for scheduled for PUSCH, cyclic shift information for DMRS (Demodulation reference signal), UL index and channel quality information required for TDD operation Quality Indicator) request information (CSI request) and the like. On the other hand, since DCI format 0 uses synchronous HARQ, it does not include a redundancy version like DCI formats related to downlink scheduling allocation. In the case of carrier offset, if cross carrier scheduling is not used, it is not included in the DCI format.

DCI format 4 is new in LTE-A Release 10 and is intended to support spatial multiplexing for uplink transmission in LTE-A. In the case of DCI format 4, since it further includes information for spatial multiplexing as compared with DCI format 0, it has a larger message size, and further includes additional control information in control information included in DCI format 0. That is, the DCI format 4 further includes a modulation and coding scheme for the second transmission block, precoding information for multi-antenna transmission, and sounding reference signal request (SRS request) information. On the other hand, since DCI format 4 has a size larger than DCI format 0, the offset separating DCI formats 0 and 1A is not included.

DCI formats 1, 1A, IB, 1C, 1D, 2, 2A, 2B, and 2C related to downlink scheduling assignment do not significantly support spatial multiplexing with 1, 1A, IB, 1C, 1D and spatial multiplication. Supporting 2 ᅳ can be divided into 2A, 2B, 2C.

DCI format 1C supports only frequency continuous allocation as a compact downlink allocation and does not include a carrier offset and a redundant version as compared to other formats.

DCI format 1A is a format for downlink scheduling and random access procedures. This includes an indicator indicating whether carrier offset, downlink distributed transmission is used, PDSCH resource allocation information, modulation and coding scheme, redundancy version, HARQ processor number to inform processor used for soft combining, The HARQ process may include a new data offset used for emptying the buffer for initial transmission, a transmit power control command for PUCCH, and an uplink index required for TDD operation.

In the case of DCI format 1, most of the control information is similar to DCI format 1A. However, DCI format 1 supports non-contiguous resource allocation, compared to DCI format 1A related to continuous resource allocation. Therefore, since DCI format 1 further includes a resource allocation header, the control signaling overhead is somewhat increased as a trade-off of increasing flexibility of resource allocation.

The DCI format IB and ID are common in that they contain precoding information as compared with DCI format 1. DCI format 1B includes PMI verification and DCI format 1D includes downlink power offset information. The control information included in the DCI format IB and ID is mostly identical to that of the DCI format 1A.

DCI formats 2, 2A, 2B, and 2C basically control information included in DCI format 1A. Including most of them, it contains more information for spatial multiplexing. This includes the modulation and coding scheme, the new data offset, and the redundancy version for the second transport block.

DCI format 2 supports closed-loop spatial multiplexing, and 2A supports open-loop spatial multiplexing. Both contain precoding information. DCI format 2B supports dual layer spatial multiplexing combined with beamforming and further includes cyclic shift information for DMRS. DCI format 2C can be understood as an extension of DCI format 2B and supports public multiplexing up to eight layers.

DCI formats 3 and 3A can be used to supplement transmission power control information included in DCI formats for uplink scheduling grant and downlink scheduling assignment, that is, to support semi-persistent scheduling. have. In the case of DCI format 3, 1 bit per terminal and 2 bit instructions for 3A are used.

Any one of the above-described DCI formats may be transmitted through one PDCCH, and a plurality of PDCCHs may be transmitted in a control region.

PDCCH processor

In transmitting the DCI on the PDCCH, a Cyclic Redundancy Check (CRC) is attached to the DCI, and in this process, a radio network temporary identifier (RNTI) is masked. Here, the RNTI may use different RNTIs according to the purpose of transmitting the DCI. Specifically, network initiation (network initiated) P-RNTI may be used for a paging message related to connection establishment, RA-RNTI for a random access, and SI-RNTI may be used for a system information block (SIB). In the case of unicast transmission, C-RNTI, which is a unique terminal identifier, may be used. DCI with CRC is coded with a predetermined code and then adjusted to the amount of resources used for transmission through rate-matching.

In the transmission of the above PDCCH, a control channel element (CCE), which is a continuous logical allocation unit, is used to map the PDCCH to the REs for efficient processing. The CCE consists of 36 REs, which corresponds to 9 units in a resource element group (REG). The number of CCEs required for a specific PDCCH depends on the DCI payload, cell bandwidth, channel coding rate, and the like, which are control information sizes. In more detail, the number of CCEs for a specific PDCCH may be defined according to the PDCCH format as shown in Table 1 below.

Table 1

As can be seen in Table 1, the number of CCEs varies depending on the PDCCH format. For example, the transmitter may use the PDCCH format by changing the PDCCH format to 2 when the channel state worsens while using the PDCCH format 0. Blind decoding

As described above, any one of four formats may be used for the PDCCH, which is not known to the UE. Therefore, the UE needs to decode without knowing the PDCCH format, which is called blind decoding. However, since it is a heavy burden for the UE to decode all possible CCEs used for downlink for each PDCCH format, a search space is defined in consideration of the scheduler limitation and the number of decoding attempts.

That is, the search space is a set of candidate PDCCHs consisting of CCEs that the UE should attempt to decode on an aggregation level. Here, the aggregation level and the number of PDCCH candidates may be defined as shown in Table 2 below.

[Table 2]

8 16 2 As shown in Table 2, since four aggregation levels exist, the terminal has a plurality of search spaces according to each aggregation level.

In addition, as shown in Table 2, the search space may be divided into a terminal specific search space and a common search space. The UE-specific discovery space is for specific UEs, and each UE monitors the UE-specific discovery space (attempting to decode a PDCCH candidate set according to a possible DCI format) to identify RNTI and CRC masked on the PDCCH. If valid, control information can be obtained.

The common search space is for a case where a plurality of terminals or all terminals need to receive the PDCCH, such as dynamic scheduling or paging message for system information. However, the common search space may be used for a specific terminal for resource operation. It may be. In addition, the common search space may overlap with the terminal specific search space.

The search space may be specifically determined by Equation 1 below.

[Equation 1]

L \ (Y _k + m ') mod [_ ^N ccE, k ^{1 L.} + ι γ γ

Where is set level, ^ is determined by RNTI and subframe number k Variable, ^m is the number of PDCCH candidates, where m '= m + M ^(L) -n _CI if carrier aggregation is applied, otherwise m' 二 m is m ^W '' ^{Z 1} and p is the number of candidate DC _DCCH , LLb ' / c is the total number of CCE, ^one of the control area in the second sub-frame k times is ^{Ζ * = 0, '·'} , ~ 1 as an argument that specifies the individual CCE in each PDCCH candidates PDCCH. Common search space γ

^K is always determined to be zero.

5 shows a UE-specific search space (shaded part) at each aggregation level that can be defined according to Equation (1). Carrier merge is not used here.

Note that N ^{CCE, k} is illustrated as 32 for convenience of explanation.

(A), (b), (c), and (d) of FIG. 5 illustrate the case of aggregation levels 1, 2, 4, and 8, respectively, and the numbers represent CCE numbers. In FIG. 5, the start CCE of the search space at each aggregation level is determined by the RNTI and the subframe number k as described above, and may be determined differently for each aggregation level due to the modulo function in the same subframe for one UE. L is always determined as a multiple of the aggregation level. Γ below

In the description, ^k is assumed to be CCE number 18 by way of example. From the start CCE, the terminal Decoding is sequentially performed in units of CCEs determined according to the corresponding aggregation level. For example, in (b) of FIG. 5, the UE attempts to decode two CCE units according to the aggregation level from CCE No. 4, which is a starting CCE.

As described above, the UE attempts to decode the search space, and the number of decoding attempts is determined by a transmission mode determined through DCI format and RRC signaling. In case carrier aggregation is not applied, the UE should consider two DCI sizes (DCI format 0 / 1A / 3 / 3A and DCI format 1C) for each of 6 PDCCH candidates for a common search space. Decryption attempt is necessary. For the UE-specific search space, up to 32 decoding attempts are required because two DCI sizes are considered for the number of PDCCH candidates (6 + 6 + 2 + 2 = 16). Therefore, up to 44 decoding attempts are required if carrier aggregation is not applied.

Meanwhile, when carrier aggregation is applied, since the UE-specific search space and the decoding for DCI format 4 are added as many as downlink resources (component carriers), the maximum number of decoding is further increased. Carrier Aggregation

6 is a diagram for explaining carrier aggregation. Before describing carrier aggregation, the concept of a cell introduced to manage radio resources in LTE-A will be described first. A cell may be understood as a combination of downlink resources and uplink resources. In this case, the uplink resource is not an essential element, and therefore, the cell is a downlink resource alone or May be composed of a downlink resource and an uplink resource. However, this

The definition in LTE-A Release 10, and vice versa, it is also possible that the cell consists of uplink resources alone. The downlink resource may be referred to as a downlink component carrier (DL CC) and the uplink resource may be referred to as an uplink component carrier (UL CC). DL CC and UL CC may be expressed as a carrier frequency (carrier frequency), the carrier frequency means a center frequency (center frequency) in the cell.

A cell may be classified into a primary cell (PCell) operating at a primary frequency and a secondary cell (SCell) operating at a secondary frequency. PCell and SCell may be collectively referred to as a serving cell. In the PCell, the terminal may perform an initial connection establishment (initial connection establishment) process, or the cell indicated in the connection reset process or handover process may be a PCell. That is, the PCell may be understood as a cell that is the center of control in a carrier aggregation environment to be described later. The UE may receive and transmit a PUCCH in its PCell. The SCell is configurable after the RRC connection is established and can be used to provide additional radio resources. In the carrier aggregation environment, the remaining serving cells except the PCell may be viewed as SCells. In the case of RRC_C0NNECTED state, but carrier aggregation is not configured or carrier aggregation is not supported, there is only one serving cell composed of PCell. On the other hand, in case of a UE in RRC_C0NNECTED state and carrier aggregation is configured, one or more serving cells exist. The total serving cell includes the PCell and the entire SCell. For a terminal supporting carrier aggregation, the network may configure one or more SCells in addition to a PCell initially configured in a connection establishment process after an initial security activation process is initiated.

Hereinafter, carrier aggregation will be described with reference to FIG. 6. Carrier aggregation is a technology introduced in LTE-A that allows the use of wider frequency bands to meet the increasing demand for higher data rates. Carrier aggregation may be defined as an aggregation of two or more component carriers (CCs) having different carrier frequencies. Referring to FIG. 6, FIG. 6 (a) shows a subframe when one CC is used in the existing LTE system, and FIG. 6 (b) shows a subframe when carrier aggregation is used. In FIG. 6B, three CCs of 20 MHz are used to support a total bandwidth of 60 MHz. Here, each CC may be continuous or may be non-continuous.

The UE may simultaneously receive and monitor downlink data through a plurality of DL CCs. The linkage between each DL CC and UL CC may be indicated by system information. DL CC / UL CC links can be fixed in the system or configured semi-statically. In addition, even if the entire system band is composed of N CCs, the frequency band that can be monitored / received by a specific terminal may be limited to M (<N) CCs. Various parameters for carrier merging may be set in a cell specific (ceU-specific), UE group-specific (UE group-specific) or UE-specific (UE-specific) manner. Cross carrier scheduling

7 is a diagram for describing cross carrier scheduling. Cross-carrier scheduling means, for example, including all downlink scheduling allocation information of another DL CC in a control region of one DL CC among a plurality of serving cells, or a DL CC of any one of a plurality of serving cells. This means that the uplink scheduling grant information for the plurality of UL CCs linked with the DL CC is included in the control region of the UE. 7 is a diagram illustrating a case where cross carrier scheduling is applied. As a premise of description, a carrier indicator field (CIF) will be described first, and FIG. 7 will be described.

As described above, the CIF may be included or not included in the DCI format transmitted through the PDCCH, and when included, it indicates that the cross carrier scheduling is applied. If cross carrier scheduling is not applied, downlink scheduling allocation information is valid on a DL CC through which current downlink scheduling allocation information is transmitted. In addition, the uplink scheduling grant is valid for one UL CC linked with the DL CC through which the downlink scheduling allocation information is transmitted.

When cross carrier scheduling is applied, the CIF indicates a CC related to downlink scheduling allocation information transmitted through a PDCCH in one DL CC. For example, referring to FIG. 7, downlink allocation information about DL CC B and DL CC C, that is, information about PDSCH resources, is transmitted through a PDCCH in a control region on DL CC A. The UE monitors the DL CC A to know the CC corresponding to the resource region of the PDSCH through the CIF. e-PDCCH

Control information included in the above-described DCI formats are defined in LTE / LTE-A.

Although described mainly on the transmission through the PDCCH, it is possible to apply to other downlink control channels other than the PDCCH, for example, ePDCCH (enhanced PDCCH). ePDCCH is an enhanced version of PDCCH that can be discussed in LTE-A Release 11. The background of the introduction is as follows.

Cellular network-based wireless communication systems have the same type of homogeneous network or different types of heterogeneous network interference. The influence of such interference may affect not only the data channel but also the control channel. In the LTE / LTE-A system, in order to alleviate inter-cell interference, a cell causing interference may select an Almost blank subframe (ABS) (a basic downlink signal (eg, Sal-specific reference signal, etc.)). Except for 0 or very weak power subframes), the interference to neighboring cells is reduced or allocated to the UE at the cell edge using inter-base station scheduling information. The frequency domain of each cell may be set to be orthogonal. However, the control channel (PDCCH, PCFICH, PHICH) may need to be transmitted in all subframes, the entire downlink bandwidth There is a problem that it is difficult to avoid interference because it is allocated and transmitted.

FIG. 8 is a technique that can be used when exchanging scheduling information between base stations, and shows a technique of allocating PDSCH in a frequency region orthogonal to terminals at a cell edge to mitigate interference. However, as described above, the PDCCH has a problem in that interference cannot be mitigated due to a reason for transmitting the entire downlink bandwidth. For example, since the time-frequency region in which the PDCCH from eNBl to UE1 is transmitted and the time-frequency region in which the PDCCH from eNB2 to UE2 are transmitted overlap, the PDCCH transmission for each of UEl and UE2 is mutually different. Interfere with and receive.

In addition, as illustrated in FIG. 9, the PUCCH or the PUSCH transmitted by the UE1 may act as an interference to the PDCCH or the PDSCH that the adjacent UE2 should receive. In this case, if the scheduling information is exchanged between the base stations, the interference on the PDSCH can be avoided by allocating the terminals to the orthogonal frequency domain, but the PDCCH is affected by the interference by the PUCCH or the PUSCH transmitted by the UE1.

For this reason, the introduction of an ePDCCH different from the current PDCCH is discussed. Of course, the ePDCCH has a purpose to effectively support CoMP (Coordinated Multipoint Transmission) and MU-MIMO (Multiuser-Multi Input Multi Output) as well as interference.

10 is a diagram illustrating time-frequency resources allocated for an ePDCCH. The time-frequency resource for the ePDCCH is the time-frequency resource region for the PDCCH in the existing LTE / LTE-A system as shown in FIG. 10 (a) (eg, the first in the subframe). A slot may be allocated in a time division multiplexing (TDM) scheme in a time-frequency resource region excluding up to four OFDM symbols from the beginning). That is, PDCCH and ePDCCH may be distinguished on the time axis. For example, the ePDCCH may be allocated to a predetermined number of OFDM symbols other than the OFDM symbol to which the PDCCH is allocated in the first slot of the subframe.

Alternatively, as shown in FIG. 10 (b), time excluding a time-frequency resource region (for example, up to four OFDM symbols from the beginning in the first slot in a subframe) in the existing LTE / LTE-A system In the frequency resource region, time-frequency resources for the ePDCCH may be allocated by frequency division multiplexing (FDM). That is, different ePDCCHs can be distinguished on the frequency axis. For example, the ePDCCH may be allocated to a predetermined number of subcarriers for the entire 0FDM symbol except for the resource region for the PDCCH in the subframe. However, the ePDCCH region shown in FIG. 10 is exemplary and may be determined in various ways, such as by allocating a combination of TDM and FDM. In other words, an area to which an ePDCCH is allocated may be set to an area that is divided from an existing PDCCH and / or another ePDCCH and one or more time resources or frequency resources. Meanwhile, the above discussions in the physical layer may include machine type communication (MTC) (which may include a device to device (D2D) or a machine to machine (M2)) and a multi user-multiple input multiple output (MU-MIM0). , CoMP (Coordinated Multipoint Tx / Rx) and the like can be used. In MTC, data transmission can occur widely within one cell boundary, many terminals can be located, and due to the characteristics of each terminal (eg refrigerator, washing machine, mobile phone, TV, laptop, etc.) It may be configured in other forms. The characteristics of these terminals may be designed by dividing them into categories as shown in Table 3 below in terms of implementation of the terminal.

Table 3

For example, in Table 3, UE category 1 is composed of terminals for low data rates, which do not support MIM0 and may have a small buffer size or memory size in the terminal, or use a simple reception algorithm. It is possible to design at low cost. On the other hand, in case of UE category 8, it requires a high data rate, so it supports MIM0 and requires a large buffer or memory, which requires expensive components for the design.

In recent MTCs, there is a need for low cost devices with small data volumes and / or limited mobility and low cost and complexity. This means that it can be implemented with lower complexity and lower cost than UE category 1, and it is necessary for the popularization and efficient operation of MTC. In the case of such a low-cost device, the blind decoding described above can be very burdensome for the terminal. Therefore, it is necessary to reduce the number of blind decoding of the terminal. However, the method for reducing the number of blind decoding of the terminal described below is not limited to the MTC device only, it is noted that it can be applied to the terminals in the existing LTE / LTE-A system. How to reduce the number of blind decoding-limit the search space

Hereinafter, a method of limiting a search space in an existing LTE / LTE-A system by applying a predetermined offset to the search space will be described. The offset may be preset. Or, the offset is of the subframe received by the current terminal The UE may be informed from the DCI of the previous subframe or may be notified to the UE through higher layer signaling. In addition, the offset may be a relative value with respect to the CCEs included in the search space or may be an absolute value that is a CCE number.

FIG. 11 is a diagram for explaining that a search space is limited by using an offset, which is a relative value. FIG. 11 exemplarily shows that the aggregation level is set at the second and kth subframes.

N _C d _CE ti ' _k / c is Y

k _k is the case where cross-carrier scheduling is not considered

^ (2) N γ search space, ^k is shown. For convenience of explanation, CCE ^ is 33 ， ^k c (2)

For example, 18. Here, the search space, ^k is Equation 1, which defines the search space in the existing LTE / LTE-A system

It is decided according to.

For example, when the offset in the search space is 4, the search space limited by the offset CCE number may be promised as one of the following.

i) If the area is smaller than the offset CCE number relative to the smallest CCE number in the search space, the restricted search space is area a.

ii) if the area is larger than the offset of the CCE number offset from the smallest CCE number in the search space, then the restricted search space is area b.

iii) if the area is smaller than the offset of the CCE number offset from the largest CCE number in the search space, then the restricted search space is the area c. iv) if the area is larger than the CCE number offset from the largest CCE number in the search space, the restricted search space is the area d.

Meanwhile, in the case of i), that is, when the search space is limited by applying an offset based on the smallest CCE number in the search space, ^m, which is the number of PDCCH candidates in Equation 1 defining the search space in the conventional LTE / LTE-A system, is limited. - ^{m ^~} ^ ^~) · in _{n CI w = o, ...,} m ( "m was defined as the _m -l二Q ... \ off _se t IL -1

Can be modified to '' ^L '. In the case of π), ^ 二 ^ ^ ", ... ， ^ "^" Can be modified to ¹ . πυ = 0, ''', M ⁽⁾ -l— Lo / _, iv) m = M ^(L) -[offset /'',. Can be modified to M ^(L) -1. 12 is a view for explaining that the search space is limited by using an offset that is an absolute value. In FIG. 12, as shown in FIG.

N _{CCE k} Y _k

The total number of CCEs in the control region, n ^ 'K is 33, ^k is 18, and cross carrier C (2)

The search space, ^k , is shown when scheduling is not taken into account.

Referring to the case where the absolute offset (CCE number) is 8, the limited search space may be promised as one of the following.

i) when limited to an area below an absolute offset, the restricted search space is

ii) where limited search space is limited to areas above the absolute offset

The limited search space in each case may be represented by Equations 2 and 3, respectively.

[Equation 2]

L {(Y _k + m) mod N _CCEk / / J} + / <offset

[Equation 3]

L {(+ ') ^ /' '} + / ≥ ^

As another method of limiting the search space using an offset all, the search space may be limited to corresponding PDCCH candidates while skipping by the offset in the search space. FIG. 13 illustrates that the search space is limited to corresponding PDCCH candidates while skipping by an offset. 13 (a) shows the smallest CCE number in the search space. The offset is applied as a reference, and FIG. 13 (b) shows that the offset is applied based on the largest CCE number in the search space. In each case, when the cross carrier scheduling is not performed, the aggregation level is the entire control area in the 2nd and kth subframes.

N _{CC ¥ k} 7,

The number of CCEs,, is 33, ^k is 18, and the offset is assumed to be 4. Referring to Figure 13 (a), the search space,

It can be seen that PDCCH candidate pel corresponding to 4, which is the smallest CCE number in P2, PDCCH candidate pc2 skipped by offset 4, and PDCCH candidate pc3 skipped by offset 4 again are determined to be limited search spaces. In this case, the UE should perform blind decoding at aggregation level 2.

The number of PDCCH candidates is reduced from six to three. The above description is the existing search hole m

In equation 1, which defines the liver, among the factors = 0, ···, ^(Ι) -1 m = 0, [offset / j ， 2 x [o

Is the same as modified. 13 (b) shows a search space,

,

It can be seen that the search space is limited by skipping by the offset toward the CCE number. Therefore, the limited search space is determined by three PDCCH candidates of pel, pc2, and pc3. In this case, one of the factors in Equation 1 that defines the existing search space m ^ Ο, -.-, ^ -Ι

= M ^{L -\-x [offset IL ..., M ^(L) -1-2 x [offset IL_

(offset / L

M ^(L) -\-(offset IL ^ M ^(L) -\

Is the same as modified. How to set offset

Meanwhile, in the methods of limiting the search space using the above-described offset, the offset value may be set in the following methods.

Firstly, the offset value can be set regardless of the aggregation level. Specifically, the UE has a search space for each of four aggregation levels, 1, 2, 4, and 8. Further, an offset value limiting the search space may be set to the same value at all aggregation levels. Can be. In this case, there is an advantage that the signal overhead can be reduced compared to setting the offset value to a different value at each set level.

Secondly, the offset value may be set in consideration of the aggregation level. That is, the offset value may be set to be proportional to the set level, or set to be proportional to the total number of CCEs included in the search space at each set level, or the offset value may be set to a different value at each set level.

Third, the offset value may be set the same for the common search space and the terminal specific search space or different for the common search space and the terminal specific search space. Can be set.

Hereinafter, a detailed description will be given of a case in which the offset value is set to be proportional to the set level and the case where the set value is proportional to the total number of CCEs included in the search space at each set level. Shall be.

When the offset value is set to be proportional to the aggregation level, as described in FIGS. 11 and 12, the offset value may be described in two cases, the relative offset and the absolute offset.

First, in the case of an offset which is a relative value, the offset value may be set as in Equation 4.

[Equation 4]

offset L) 二 offset, L where is the set level, ⁰ ff ^set may be a value determined irrespective of the set level, or may be the offset mentioned in the description of FIGS. 11 and 12, in which case offset is represented by _u and It can be understood that the offset mentioned in the description of FIG. ₁₂ is reset. Table 4 below shows an example of offset values in the case of off set and two 2.

Table 4

II ᅳ offset (L)

In Tables 4 and 5, when the offset value is larger than the size of the search space or the offset value equal to the size of the search space, the search space is not limited by the offset, that is, the same as the existing search space. It can be understood that. Alternatively, the search space may be applied by increasing the offset value.

Meanwhile, in the case of Equation 4, the offset value is the number of CCEs included in each set level. In this case, Equation 4 may be rewritten as Equation 5.

[Equation 5]

offsetL) = min (offsefxL, # size of CCEs in aggregation level L) where is the aggregation level, # size of CCEs in aggregation level is the number of CCEs included in the search space at the aggregation level and can also be expressed as ^ χΜ ^(ζ °). Table 6 below is an example of applying Equation 5 in the case of ° ff ^Set二 ^ as in the case of Table 5.

Table 6

Next, even in the case of an absolute offset, it may be set as in Equation 6 to be proportional to the set level.

[Equation 6] offset L) = qffse xL

In the case of Equation 6, the offset value determined to be proportional to the aggregation level may be limited to the total number of CCEs included in the subframe as shown in Equation 7.

[Equation 7]

offset (L) = miniqffse xL, N ₍ CCE, A: where

Is the total number of CCEs of the control region in the urine subframe. For example, in the case of off set, two 2 _, N _{CCE, k} = 100, the offset value to which Equation ₆ is applied is shown in Table 7 and the offset value to which Equation 7 is applied to Table 8.

Table 7

[Table 8]

Seekspace offset (L)

Subsequently, a case in which the flick is set proportionally to the total number of CCEs included in the search space at each aggregation level will be described. In this case, it can be explained in two cases, offset relative and absolute offset.

In the case of an offset that is a relative value first, the offset value may be set as Equation 8 below or as shown in Equation 9 in which the offset value is limited to the number of CCEs included in each set level.

[Equation 8]

# size of CCEs in aggregation level L ffset (L) =

offsef

[Equation 9]

offset (L) =

KR2012 / 001253

In the above equation,

It may be a value determined irrespective of the aggregation level, or may be an offset mentioned in the description of FIGS. 11 and 12,

# size of CCEs in aggregation level L may be represented as ^ xM ⁽⁾ as the number of CCEs included in the search space at aggregation level L. Table 9 below shows an example of offset values in the case of off set 、二 <.

Table 9

It can be set as shown in Equation 11 to limit the preset value to the total number of CCEs included in the subframe.

[Equation 10]

# size of CCEs in aggregation level L

offsef [Equation 11]

In Equations 8 to 11, ⁰ ff ^Set may be a nonzero rational number. Table 10 below is an example of offset values in the case of ffset 、二.

Table 10

How to reduce the number of blind decoding-bitmap signaling

Hereinafter, as another method for reducing the number of blind decoding, it will be described to inform, through bitmap signaling, which PDCCH candidates the DCI transmitted to a specific UE in the search space of each aggregation level is included in. Here, the bitmap may inform the terminal through higher layer signaling. 14 is a diagram illustrating a bit blind configuration for reducing the number of blind decoding.

Referring to FIG. 14, a bitmap includes 22 bits, and each bit represents a PDCCH candidate to be monitored by the UE. A bit of 1 means that a DCI exists in a corresponding PDCCH candidate.

In detail, the UE monitors a total of 16 PDCCH candidates for all aggregation levels (1, 2, 4, and 8) in the UE-specific search space. In addition, the UE has a total of six PDCCH candidates at all aggregation levels (4, 8) in the common search space. Accordingly, a total of 22 PDCCH candidates to be monitored by the UE at each aggregation level are arranged, which are arranged in the order of the aggregation level for the UE-specific discovery space as shown in FIG. Bitmaps can be constructed by arranging them in the order of size. The terminal knows the bitmap configured as described above through higher layer signaling and the like, and monitors only PDCCH candidates of a set level corresponding to a bit indicated by 1 in the bitmap, compared to conventional monitoring of 22 PDCCH candidates. Since the number of decoding operations can be performed, the number of decoding can be greatly reduced. For example, a bit indicated by 1 in FIG. 14 is a third PDCCH candidate of aggregation level 1 in the UE-specific search space and a second PDCCH candidate of aggregation level 4 in the common discovery space. Accordingly, the UE may acquire DCI transmitted to itself by monitoring only these two locations.

15 shows another configuration of BitTem for reducing the number of blind decoding. It is a figure which shows.

In FIG. 14, the bitmap is composed of 22 bits, whereas in FIG. 15, the bitmap can be configured with 16 bits. The bit blind may be configured with an aggregation level indication bit and location bits indicating the number of PDCCH candidates among the PDCCH candidates.

Specifically, in the case of the UE-specific search space, the number of four sets of 1,2, 4, and 8 aggregation levels is present, and this can be represented using 2 bits. Since there are a maximum of six PDCCH candidates in the aggregation level, three bits may be used to inform that a DCI is allocated. Here, a total of 10 bits may be used as 5 bits for aggregation levels 1 and 2 and 5 bits for aggregation levels 4 and 8. In the case of the common search space, since there are two sets of 4 and 8 aggregation levels, it can be represented by 1 bit, and since the maximum number of PDCCH candidates is 4, it can inform that DCI is allocated using 2 bits. Here, a total of 6 bits may be used as 3 bits for the aggregation level 4 and 3 bits for the aggregation level 8. For example, in FIG. 15, DCI is allocated to a third PDCCH candidate position when the aggregate level is 1 in a UE-specific search space and a second PDCCH candidate position when the aggregate level is 4 in the common discovery space. Set to 1 to inform the UE of the location of DCI allocation in a bitmap.

In addition, the bit blind may be composed of 8 bits as shown in FIG. In the UE-specific search space, a total of 5 bits may be used as 3 bits to indicate positions of 2 bits and PDCCH candidates (maximum of 6) to indicate aggregation levels 1, 2, 4, and 8. Common navigation In the case of space, a total of 3 bits may be used as 2 bits to indicate 1 bit and PDCCH candidates (maximum 4) to indicate aggregation levels 4 and 8. Herein, the aggregation level is represented by i) bit values 00, 01, 10, and 11 in the terminal specific search space, respectively, meaning aggregation levels 1, 2, 4, and 8, and ii) bit values in the common search space. 0 and 1 may be set to mean aggregation levels 4 and 8. Applying the above description to FIG. 15, since 2 bits indicating the aggregation level in the UE-specific search space are 00, the aggregation level is 1, and 3 bits indicating the PDCCH allocation is 010, which is interpreted as indicating the third PDCCH candidate. Can be. In the common search space, since one bit indicating the aggregation level is 0, the aggregation level is 4 and the 2 bits indicating the PDCCH allocation are 10 and thus may be interpreted as indicating the third PDCCH candidate. However, in this case, only one DCI per aggregation level is transmitted in CSS and USS, and thus its use may be limited.

17 is a flowchart illustrating an exemplary PDCCH transmission / reception method of the present invention.

In step S1710, the UE may determine a search space consisting of PDCCH candidates on a subframe. As described above, the search space is determined by the CCE number determined by the aggregation level, the subframe number and the identifier of the UE, the number of PDCCH candidates in the aggregation level, and the like. In particular, the offset may be applied.

In step S1720, the UE may attempt to decode PDCCH candidates in the search space in step S1710. In this case, the UE may perform CRC demasking using its identifier (RNTI). In step S1730, the UE may receive downlink control information in the case of the PDCCH in which both the CRC and its identifier are confirmed.

With regard to the method for receiving search space monitoring and control information of a terminal according to the present invention described with reference to FIG. 17, the above-described matters described in various embodiments of the present invention may be independently applied or two or more embodiments may be simultaneously applied. Duplicate content is omitted for clarity.

Base station device and terminal device

18 is a diagram illustrating the configuration of a base station apparatus and a terminal apparatus according to the present invention.

Referring to FIG. 18, the base station apparatus 1810 according to the present invention may include a receiving module 1811, transmission modules 1812, a processor 1813, a memory 1814, and a plurality of antennas 1815. . The plurality of antennas 1815 means a base station apparatus supporting MIM0 transmission and reception. The reception modules 1811 may receive various signals, data, and information on uplink from the terminal. The transmission modules 1812 may transmit various signals, data, and information on downlink to the terminal. The processor 1813 may control operations of the base station apparatus 1810 in general.

The base station apparatus 1810 according to an embodiment of the present invention may be configured to transmit control information for uplink multi-antenna transmission. The processor 1813 of the base station apparatus may be configured to transmit the DCI on the PDCCH, via the transmission modules 1812. In addition, the processor 1813, the physical downlink control channel for a specific terminal Determine a set level corresponding to the number of CCEs required for the (PDCCH), and map the control information to any one PDCCH candidate in a search space consisting of PDCCH candidates each including the determined number of CCEs; The space may be determined by the aggregation level, the number of PDCCH candidates according to the aggregation level, and a predetermined offset. In this case, the search space limitation may be applied to the above-described methods related to the limitation of the search space, and the offset which is a predetermined offset may also be determined by the above-described offset setting method.

In addition, the processor 1813 of the base station apparatus 1810 performs a function of processing the information received by the base station apparatus 1810, information to be transmitted to the outside, and the like. Can be stored and replaced with components such as buffers (not shown).

Referring to FIG. 18, the terminal device 1820 according to the present invention may include reception modules 1821, transmission modules 1822, a processor 1827, a memory 1824, and a plurality of antennas 1825. have. The plurality of antennas 1825 means a terminal device supporting MIM0 transmission and reception. Receive modules 1821 may receive various signals, data, and information on downlink from the base station. The transmission modules 1822 may transmit various signals, data, and information on the uplink to the base station. The processor 1827 may control operations of the entire terminal device 1820.

The terminal device 1820 according to an embodiment of the present invention may be configured to perform uplink multiple antenna transmission. The processor 1823 of the terminal device receives the receiving modules. It may be configured to receive the PDCCH via 1821. In addition, the processor 1813 may be configured to attempt decoding on a search space consisting of PDCCH candidates for control information. The search space in which the decoding is attempted may be determined by an aggregation level corresponding to the number of CCEs included in each of the PDCCH candidates, the number of PDCCH candidates according to the aggregation level, and a predetermined offset. Herein, the limitations of the search space may be applied to the above-described methods related to the limitation of the search space, and the offset which is a predetermined offset may also be determined by the above-described offset setting method.

In addition, the processor 1831 of the terminal device 1820 performs a function of processing information received by the terminal device 1820, information to be transmitted to the outside, and the memory 1824 performs a predetermined time for calculating the processed information and the like. Can be stored and replaced with components such as buffers (not shown).

Specific configurations of the base station apparatus and the terminal apparatus as described above may be implemented such that the above-described matters described in various embodiments of the present invention may be independently applied or two or more embodiments may be applied at the same time. Omit.

In addition, in the description of FIG. 18, the description of the base station apparatus 1810 may be equally applicable to a relay apparatus as a downlink transmitting entity or an uplink receiving entity, and the description of the terminal device 1820 may be a downlink. The same may be applied to the relay apparatus as a receiving subject or an uplink transmitting subject. Embodiments of the present invention described above may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may include one or more ASICs (Applicat Specific Specific Circuits), DSPs CDigital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), PLDs (Pr ogr ammab 1 e Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of modules, procedures, or functions for performing the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

Detailed description of the preferred embodiments of the present invention disclosed as described above is provided to enable those skilled in the art to implement and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will understand that various modifications and changes can be made without departing from the scope of the present invention. For example, those skilled in the art Each of the components described in the embodiments described above can be used in combination with each other. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The invention can be embodied in other specific forms without departing from the spirit and essential features of the invention. Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims and all changes that come within the equivalent scope of the invention are included in the scope of the invention. The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, the claims may be incorporated into claims that do not have an explicit citation relationship in the claims, or may be incorporated into new claims by amendment after filing.

Industrial Applicability

Embodiments of the present invention as described above may be applied to various mobile communication systems.

Claims

[Range of request]

[Claim 11

In a method of receiving control information from a terminal in a wireless communication system,

Determining a search space consisting of physical downlink control channel (PDCCH) candidates on a subframe from the base station; And

Attempting to decode each of the PDCCH candidates on the search space;

The search space to which the decoding is attempted may include factors including an aggregation level based on the number of control channel elements (CCEs) included in each of the PDCCH candidates, the number of PDCCH candidates according to the aggregation level, and a predetermined offset. The control information receiving method determined by.

[Claim 2]

In that U term,

The search space is determined by one or more PDCCH candidates corresponding to the CCE number shifted by the predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal.

[Claim 3]

The method of claim 1,

The search space is one or more corresponding to a previous CCE number moved by the predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal. The PDCCH candidates are determined, the control information receiving method.

[Claim 8]

The method of claim 1,

The search space is determined by one or more PDCCH candidates including a CCE corresponding to an integer multiple of the predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal.

[Claim 4]

The method of claim 1,

And the predetermined offset is reset in consideration of the aggregation level.

[Claim 5]

In the contrary,

The predetermined offset is reset to a smaller value of a value obtained by multiplying the predetermined offset by the aggregation level and the number of CCEs corresponding to the search space when the predetermined offset is not applied in the aggregation level. .

[Claim 6]

The method of claim 4,

And the predetermined offset is reset to be proportional to the number of CCEs corresponding to the search space when the predetermined offset is not applied.

[Claim 7] The method of claim 6,

The predetermined offset is reset to a smaller value of a quotient obtained by dividing the number of CCEs corresponding to the search space when the predetermined offset is not applied by the predetermined offset and the number of CCEs corresponding to the search space when the predetermined offset is not applied. That is, the control information receiving method.

[Claim 8]

The method of claim 1,

The predetermined offset is determined from any one of control information and higher layer signaling of a subframe received before the subframe.

[Claim 9]

In a method for transmitting control information from a base station in a wireless communication system,

Determining a search space consisting of physical downlink control channel (PDCCH) candidates on the downlink subframe; And

Transmitting the control information through one PDCCH among the PDCCH candidates in the search space;

Including;

The search space is determined by factors including an aggregate level, the number of PDCCH candidates according to the aggregate level, and a predetermined offset, the number of control channel elements (CCEs) included in each of the PDCCH candidates. Control Information Transmission Method.

[Claim 10]

The method of claim 9,

[Claim 11]

The method of claim 9,

The search space is determined by one or more PDCCH candidates corresponding to a CCE number shifted by the predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal.

[Claim 12]

The method of claim 9,

The search space is determined by one or more PDCCH candidates including a CCE corresponding to an integer multiple of a predetermined offset from the CCE number determined by the subframe number and the identifier of the terminal.

[Claim 13]

An apparatus for receiving control information in a wireless communication system,

Receiving modules; And

Includes a processor,

The processor establishes a search space composed of PDCCH candidates. Determine, and attempt to decode each of the PDCCH candidates in the search space, and the search space in which the decoding is attempted is an aggregation level corresponding to the number of control channel elements (CCEs) included in each of the PDCCH candidates. Device determined by factors including a number of PDCCH candidates according to the aggregation level and a predetermined predetermined offset.

[Claim 14]

In the device for transmitting control information in a wireless communication system,

Transmission modules; And

Includes a processor,

The processor determines a search space consisting of physical downlink control channel (PDCCH) candidates on a downlink subframe, controls the control information to be transmitted through one of the PDCCH candidates in the search space, and The search space is determined by factors including an aggregation level based on the number of control channel elements (CCEs) included in each of the PDCCH candidates, the number of PDCCH candidates according to the aggregation level, and a predetermined predetermined offset. Being, device.