Method and apparatus for transmitting and receiving wireless signal in wireless communication system

Method and apparatus for transmitting and receiving wireless signals in a wireless communication system

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving a wireless signal. The wireless communication system includes a carrier aggregation (CA)-based wireless communication system.

Wireless communication systems are being widely deployed to provide various types of communication services such as voice and data. In general, a wireless communication system is a multiple access system that can support communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of the multiple access system include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and a single carrier frequency (SC-FDMA) system. division multiple access) systems.

<p>SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for efficiently performing a wireless signal transmission/reception process.</p><p>The technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description.</p>

<p>In one aspect of the present invention, in a method for a terminal to perform communication in a wireless communication system, Downlink Control Information (DCI) including UL scheduling information for a plurality of subframes is received, wherein the DCI is a Sounding Reference Signal (SRS). ) further including request information; and transmitting SRS only once through a pre-designated subframe in the plurality of subframes according to the indication of the SRS request information, wherein the pre-designated subframe is UL transmission scheduled within the plurality of subframes A method is provided in which the first subframe in which UL transmission is scheduled or the last subframe in which UL transmission is scheduled includes.</p><p>In another aspect of the present invention, in a terminal used in a wireless communication system, RF (Radio Frequency) module; and a processor, wherein the processor receives Downlink Control Information (DCI) including UL scheduling information for a plurality of subframes, wherein the DCI further includes Sounding Reference Signal (SRS) request information, the SRS request According to an indication of information, the SRS is configured to be transmitted only once through a pre-designated subframe in the plurality of subframes, and the pre-designated subframe is a first subframe in which UL transmission is scheduled within the plurality of subframes, or A terminal including the last subframe in which UL transmission is scheduled is provided.</p><p>Preferably, based on the UL scheduling information, a plurality of UL transmissions may be further performed in the plurality of subframes.</p><p>Preferably, the UL transmission may include a Physical Uplink Shared Channel (PUSCH).</p><p>Preferably, the DCI includes UL scheduling information for a plurality of subframes on an unlicensed cell (UCell) operating in an unlicensed band, and the SRS may be transmitted on the UCell.</p><p>Preferably, the DCI may be received on the UCell or a licensed cell (LCell) operating in a licensed band.</p><p>Preferably, the DCI may further include information indicating the number of subframes in which UL transmission is scheduled in the plurality of subframes.</p><p>Preferably, the wireless communication system may include a Long Term Evolution (LTE) License Assisted Access (LAA)-based wireless communication system.</p><p>In another aspect of the present invention, in a method for a terminal to perform communication in a wireless communication system, receiving DCI (Downlink Control Information) including UL scheduling information for a plurality of subframes, wherein the DCI is UL transmission scheduling Further comprising information indicating the number Nsf of the subframes, and based on the UL scheduling information, performing Nsf UL transmissions in the plurality of subframes, wherein the size of the DCI is the size of the UL transmission to be scheduled. It is defined according to Nsf_max, the maximum number of possible subframes, and a method in which Nsf is smaller than Nsf_max is provided.</p><p>In another aspect of the present invention, in a terminal used in a wireless communication system, RF (Radio Frequency) module; and a processor, wherein the processor receives Downlink Control Information (DCI) including UL scheduling information for a plurality of subframes, wherein the DCI indicates the number of subframes in which UL transmission is scheduled, Nsf, the UL The terminal is configured to perform Nsf UL transmissions in the plurality of subframes based on scheduling information, and the size of the DCI is defined according to Nsf_max, the maximum number of subframes in which UL transmission can be scheduled, and Nsf is smaller than Nsf_max. This can be provided.</p><p>Preferably, the size of the DCI is defined based on Nsf_max New Data Indication (NDI) bits, and only Nsf NDI bits corresponding to a subframe in which UL transmission is scheduled may be used in the DCI.</p><p>Preferably, the DCI includes first information commonly applied to Nsf subframes, second information applied to only one subframe among Nsf subframes, and individually applied to each subframe belonging to Nsf subframes. including third information;</p><p>- The first information includes RA (Resource Allocation) information, MCS (Modulation and Coding Scheme) information, DMRS CS (Demodulation Reference Signal Cyclic Shift) information, and TPC (Transmit Power Control) information,</p><p>- The second information includes CSI (Channel State Information) request information, and SRS (Sounding Reference Signal) information,</p><p>- The third information may include New Data Indicator (NDI) information, Redundancy Version (RV) information, and Hybrid ARQ (HARQ) process number information.</p>

<p>According to the present invention, wireless signal transmission and reception can be efficiently performed in a wireless communication system.</p><p>The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.</p>

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as a part of the detailed description to help the understanding of the present invention, provide embodiments of the present invention, and together with the detailed description, explain the technical spirit of the present invention. 1 illustrates physical channels used in a 3GPP LTE (-A) system, which is an example of a wireless communication system, and a general signal transmission method using them. 2 illustrates the structure of a radio frame. 3 illustrates a resource grid of a downlink slot. 4 shows the structure of a downlink subframe. 5 illustrates an Enhanced Physical Downlink Control Channel (EPDCCH). 6 illustrates the structure of an uplink subframe used in LTE (-A). 7 illustrates uplink-downlink frame timing. 8 illustrates an Uplink Hybrid Automatic Repeat reQuest (UL HARQ) operation. 9 illustrates a carrier aggregation (CA) communication system. 10 illustrates cross-carrier scheduling. 11 illustrates carrier aggregation of a licensed band and an unlicensed band. 12-13 illustrate a method of occupying a resource within an unlicensed band. 14 illustrates a UL transmission process according to the present invention. 15 illustrates an SRS transmission process according to the present invention. 16 illustrates a base station and a terminal that can be applied to the present invention.

The following technologies include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. It can be used in various wireless access systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as Global System for Mobile communications (GSM)/General Packet Radio Service (GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented with a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), and the like. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) long term evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA, and LTE-A (Advanced) is an evolved version of 3GPP LTE. For clarity of explanation, 3GPP LTE/LTE-A is mainly described, but the technical spirit of the present invention is not limited thereto.

In a wireless communication system, a terminal receives information through a downlink (DL) from a base station, and the terminal transmits information through an uplink (UL) to the base station. Information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist according to the type/use of the information they transmit and receive.

1 is a diagram for explaining physical channels used in a 3GPP LTE (-A) system and a general signal transmission method using them.

In a state in which the power is turned off, the power is turned on again, or a terminal newly entering a cell performs an initial cell search operation such as synchronizing with the base station in step S101. To this end, the UE receives a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station, synchronizes with the base station, and provides information such as cell identity. acquire Thereafter, the terminal may receive a physical broadcast channel (PBCH) from the base station to obtain intra-cell broadcast information. On the other hand, the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

After completing the initial cell search, the UE receives a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to the physical downlink control channel information in step S102 to receive more specific information. System information can be obtained.

Thereafter, the terminal may perform a random access procedure such as steps S103 to S106 to complete access to the base station. To this end, the UE transmits a preamble through a physical random access channel (PRACH) (S103), and a response message to the preamble through a physical downlink control channel and a corresponding physical downlink shared channel can be received (S104). In the case of contention based random access, a contention resolution procedure such as transmission of an additional physical random access channel (S105) and reception of a physical downlink control channel and a corresponding physical downlink shared channel (S106) ) can be done.

After performing the procedure as described above, the UE performs a physical downlink control channel/physical downlink shared channel reception (S107) and a physical uplink shared channel (Physical Uplink Shared Channel, PUSCH)/ Physical uplink control channel (PUCCH) transmission (S108) may be performed. Control information transmitted by the terminal to the base station is collectively referred to as uplink control information (UCI). UCI includes HARQ ACK/NACK (Hybrid Automatic Repeat and reQuest Acknowledgment/Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), and the like. CSI includes a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), and a Rank Indication (RI). UCI is generally transmitted through PUCCH, but may be transmitted through PUSCH when control information and traffic data are to be transmitted at the same time. In addition, the UCI may be transmitted aperiodically through the PUSCH according to a request/instruction of the network.

2 illustrates the structure of a radio frame. Uplink/downlink data packet transmission is performed in units of subframes, and a subframe is defined as a time interval including a plurality of symbols. The 3GPP LTE standard supports a type 1 radio frame structure applicable to frequency division duplex (FDD) and a type 2 radio frame structure applicable to time division duplex (TDD).

2( a ) illustrates the structure of a Type 1 radio frame. A downlink radio frame consists of 10 subframes, and one subframe consists of two slots in a time domain. A time taken for one subframe to be transmitted is referred to as a transmission time interval (TTI). For example, the length of one subframe may be 1 ms, and the length of one slot may be 0.5 ms. One slot includes a plurality of OFDM symbols in the time domain and includes a plurality of resource blocks (RBs) in the frequency domain. In the 3GPP LTE system, since OFDM is used in downlink, an OFDM symbol represents one symbol interval. An OFDM symbol may also be referred to as an SC-FDMA symbol or symbol interval. A resource block (RB) as a resource allocation unit may include a plurality of consecutive subcarriers in one slot.

The number of OFDM symbols included in the slot may vary according to the configuration of a CP (Cyclic Prefix). The CP includes an extended CP and a normal CP. For example, when OFDM symbols are configured by a normal CP, the number of OFDM symbols included in one slot may be seven. When an OFDM symbol is configured by an extended CP, since the length of one OFDM symbol is increased, the number of OFDM symbols included in one slot is less than that of a normal CP. For example, in the case of the extended CP, the number of OFDM symbols included in one slot may be six. When the channel state is unstable, such as when the terminal moves at a high speed, the extended CP may be used to further reduce inter-symbol interference.

When the normal CP is used, since the slot includes 7 OFDM symbols, the subframe includes 14 OFDM symbols. Up to three first OFDM symbols of a subframe may be allocated to a physical downlink control channel (PDCCH), and the remaining OFDM symbols may be allocated to a physical downlink shared channel (PDSCH).

2(b) illustrates the structure of a Type 2 radio frame. The type 2 radio frame consists of two half frames. A half frame includes 4 (5) normal subframes and 1 (0) special subframes. The general subframe is used for uplink or downlink according to UL-DL configuration (Uplink-Downlink Configuration). A subframe consists of two slots.

Table 1 illustrates a subframe configuration in a radio frame according to the UL-DL configuration.

<tables num="1"><table><tgroup cols="12"><colspec colnum="1" align="justify" colname="col1" colwidth="2160" /><colspec colnum="2" align="justify" colname="col2" colwidth="2615" /><colspec colnum="3" align="justify" colname="col3" colwidth="644" /><colspec colnum="4" align="justify" colname="col4" colwidth="639" /><colspec colnum="5" align="justify" colname="col5" colwidth="619" /><colspec colnum="6" align="justify" colname="col6" colwidth="600" /><colspec colnum="7" align="justify" colname="col7" colwidth="633" /><colspec colnum="8" align="justify" colname="col8" colwidth="600" /><colspec colnum="9" align="justify" colname="col9" colwidth="607" /><colspec colnum="10" align="justify" colname="col10" colwidth="600" /><colspec colnum="11" align="justify" colname="col11" colwidth="600" /><colspec colnum="12" align="justify" colname="col12" colwidth="600" /><tbody><row><entry align="justify" colname="col1" morerows="1">Uplink-downlink configuration</entry><entry align="justify" colname="col2" morerows="1">Downlink-to-Uplink Switch point periodicity</entry><entry align="justify" namest="col3" nameend="col12">Subframe number</entry></row><row><entry align="justify" colname="col3">0</entry><entry align="justify" colname="col4">1</entry><entry align="justify" colname="col5">2</entry><entry align="justify" colname="col6">3</entry><entry align="justify" colname="col7">4</entry><entry align="justify" colname="col8">5</entry><entry align="justify" colname="col9">6</entry><entry align="justify" colname="col10">7</entry><entry align="justify" colname="col11">8</entry><entry align="justify" colname="col12">9</entry></row><row><entry align="justify" colname="col1">0</entry><entry align="justify" colname="col2">5ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">U</entry><entry align="justify" colname="col7">U</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">S</entry><entry align="justify" colname="col10">U</entry><entry align="justify" colname="col11">U</entry><entry align="justify" colname="col12">U</entry></row><row><entry align="justify" colname="col1">1</entry><entry align="justify" colname="col2">5ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">U</entry><entry align="justify" colname="col7">D</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">S</entry><entry align="justify" colname="col10">U</entry><entry align="justify" colname="col11">U</entry><entry align="justify" colname="col12">D</entry></row><row><entry align="justify" colname="col1">2</entry><entry align="justify" colname="col2">5ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">D</entry><entry align="justify" colname="col7">D</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">S</entry><entry align="justify" colname="col10">U</entry><entry align="justify" colname="col11">D</entry><entry align="justify" colname="col12">D</entry></row><row><entry align="justify" colname="col1">3</entry><entry align="justify" colname="col2">10ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">U</entry><entry align="justify" colname="col7">U</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">D</entry><entry align="justify" colname="col10">D</entry><entry align="justify" colname="col11">D</entry><entry align="justify" colname="col12">D</entry></row><row><entry align="justify" colname="col1">4</entry><entry align="justify" colname="col2">10ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">U</entry><entry align="justify" colname="col7">D</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">D</entry><entry align="justify" colname="col10">D</entry><entry align="justify" colname="col11">D</entry><entry align="justify" colname="col12">D</entry></row><row><entry align="justify" colname="col1">5</entry><entry align="justify" colname="col2">10ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">D</entry><entry align="justify" colname="col7">D</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">D</entry><entry align="justify" colname="col10">D</entry><entry align="justify" colname="col11">D</entry><entry align="justify" colname="col12">D</entry></row><row><entry align="justify" colname="col1">6</entry><entry align="justify" colname="col2">5ms</entry><entry align="justify" colname="col3">D</entry><entry align="justify" colname="col4">S</entry><entry align="justify" colname="col5">U</entry><entry align="justify" colname="col6">U</entry><entry align="justify" colname="col7">U</entry><entry align="justify" colname="col8">D</entry><entry align="justify" colname="col9">S</entry><entry align="justify" colname="col10">U</entry><entry align="justify" colname="col11">U</entry><entry align="justify" colname="col12">D</entry></row></tbody></tgroup></table></tables>

In the table, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The special subframe includes a Downlink Pilot TimeSlot (DwPTS), a Guard Period (GP), and an Uplink Pilot TimeSlot (UpPTS). DwPTS is used for initial cell search, synchronization, or channel estimation in the UE. UpPTS is used to synchronize the channel estimation in the base station with the uplink transmission synchronization of the terminal. The guard period is a period for removing interference generated 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, the number of slots, and the number of symbols in the radio frame may be variously changed.

3 illustrates a resource grid of downlink slots.

Referring to FIG. 3 , a downlink slot includes a plurality of OFDM symbols in the time domain. Here, it has been exemplified that one downlink slot includes 7 OFDM symbols, and one resource block (RB) includes 12 subcarriers in the frequency domain. However, the present invention is not limited thereto. Each element on the resource grid is referred to as a resource element (Resource Element, RE). One RB includes 12×7 REs. The number of RBs included in the downlink slot NDL depends on the downlink transmission band. The structure of the uplink slot may be the same as that of the downlink slot.

4 illustrates the structure of a downlink subframe.

Referring to FIG. 4 , a maximum of 3 (4) OFDM symbols located in front of a first slot in a subframe correspond to a control region to which a control channel is allocated. The remaining OFDM symbols correspond to a data region to which a physical downlink shared chance (PDSCH) is allocated, and the basic resource unit of the data region is an RB. Examples of the downlink control channel used in LTE include a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH). The PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols used for transmission of a control channel in the subframe. The PHICH is a response to uplink transmission and carries a HARQ ACK/NACK (acknowledgment/negative-acknowledgment) signal. Control information transmitted through the PDCCH is referred to as downlink control information (DCI). DCI includes uplink or downlink scheduling information or an uplink transmit power control command for an arbitrary terminal group.

Control information transmitted through the PDCCH is referred to as downlink control information (DCI). For the DCI format, formats 0, 3, 3A, 4 for uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C for downlink are defined. The type of information field, the number of information fields, the number of bits of each information field, etc. vary according to the DCI format. For example, the DCI format may include a hopping flag, an RB assignment, a modulation coding scheme (MCS), a redundancy version (RV), a new data indicator (NDI), a transmit power control (TPC), Information such as HARQ process number and PMI (precoding matrix indicator) confirmation is optionally included. Accordingly, the size of the control information matched to the DCI format varies according to the DCI format. Meanwhile, any DCI format may be used to transmit two or more types of control information. For example, DCI format 0/1A is used to carry DCI format 0 or DCI format 1, and they are distinguished by a flag field.

The PDCCH includes a transmission format and resource allocation of a downlink shared channel (DL-SCH), resource allocation information on an uplink shared channel (UL-SCH), paging information on a paging channel (PCH), and system information on the DL-SCH. ), resource allocation information of higher-layer control messages such as random access responses transmitted on PDSCH, transmission power control commands for individual terminals within an arbitrary terminal group, activation of voice over IP (VoIP), etc. . A plurality of PDCCHs may be transmitted in the control region. The UE may monitor a plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or a plurality of consecutive CCEs (consecutive control channel elements). The CCE is a logical allocation unit used to provide a PDCCH of a predetermined coding rate according to the state of a radio channel. The CCE corresponds to a plurality of resource element groups (REGs). The format of the PDCCH and the number of bits of the available PDCCH are determined according to the correlation between the number of CCEs and the code rate provided by the CCEs. The base station determines the PDCCH format according to the DCI to be transmitted to the terminal, and adds a cyclic redundancy check (CRC) to the control information. The CRC is masked with a unique identifier (referred to as a radio network temporary identifier (RNTI)) according to the owner or use purpose of the PDCCH. If the PDCCH is for a specific UE, a unique identifier (eg, C-RNTI (cell-RNTI)) of the UE is masked to the CRC. As another example, if the PDCCH is for a paging message, a paging indication identifier (eg, paging-RNTI (P-RNTI)) is masked to the CRC. If the PDCCH relates to system information (more specifically, a system information block (SIB) to be described later), a system information identifier (eg, system information RNTI (SI-RNTI)) is masked to the CRC. A random access-RNTI (RA-RNTI) is masked to the CRC to indicate a random access response, which is a response to the UE's transmission of the random access preamble.

The PDCCH carries a message known as Downlink Control Information (DCI), and the DCI includes resource allocation and other control information for one terminal or group of terminals. In general, a plurality of PDCCHs may be transmitted in one subframe. Each PDCCH is transmitted using one or more Control Channel Elements (CCEs), and each CCE corresponds to 9 sets of 4 resource elements. The four resource elements are referred to as REG (Resource Element Group). Four QPSK symbols are mapped to one REG. The resource element allocated to the reference signal is not included in the REG, so the total number of REGs in a given OFDM symbol varies depending on whether a cell-specific reference signal exists. The REG concept (ie, group-wise mapping, each group includes 4 resource elements) is also used for other downlink control channels (PCFICH and PHICH). That is, REG is used as a basic resource unit of the control region. Four PDCCH formats are supported as listed in Table 2.

<tables num="2"><table><tgroup cols="4"><colspec colnum="1" align="justify" colname="col1" colwidth="2489" /><colspec colnum="2" align="justify" colname="col2" colwidth="2717" /><colspec colnum="3" align="justify" colname="col3" colwidth="2564" /><colspec colnum="4" align="justify" colname="col4" colwidth="3019" /><tbody><row><entry align="justify" colname="col1">PDCCH format</entry><entry align="justify" colname="col2">Number of CCEs (n)</entry><entry align="justify" colname="col3">Number of REGs</entry><entry align="justify" colname="col4">Number of PDCCH bits</entry></row><row><entry align="justify" colname="col1">0</entry><entry align="justify" colname="col2">1</entry><entry align="justify" colname="col3">9</entry><entry align="justify" colname="col4">72</entry></row><row><entry align="justify" colname="col1">1</entry><entry align="justify" colname="col2">2</entry><entry align="justify" colname="col3">8</entry><entry align="justify" colname="col4">144</entry></row><row><entry align="justify" colname="col1">2</entry><entry align="justify" colname="col2">4</entry><entry align="justify" colname="col3">36</entry><entry align="justify" colname="col4">288</entry></row><row><entry align="justify" colname="col1">3</entry><entry align="justify" colname="col2">5</entry><entry align="justify" colname="col3">72</entry><entry align="justify" colname="col4">576</entry></row></tbody></tgroup></table></tables>

CCEs are numbered and used consecutively, and to simplify the decoding process, a PDCCH having a format consisting of n CCEs can be started only with CCEs with a number equal to a multiple of n. The number of CCEs used for transmission of a specific PDCCH is determined by the base station according to channel conditions. For example, when the PDCCH is for a terminal having a good downlink channel (eg, close to a base station), one CCE may be sufficient. However, in the case of a UE having a bad channel (eg, close to a cell boundary), 8 CCEs may be used to obtain sufficient robustness. In addition, the power level of the PDCCH may be adjusted according to the channel condition.

A method introduced in LTE is to define a limited set of CCE locations where a PDCCH can be located for each UE. A limited set of CCE locations where the UE can find its PDCCH may be referred to as a search space (SS). In LTE, the search space has a different size according to each PDCCH format. In addition, UE-specific and common search spaces are defined separately. A UE-specific search space (UE-Specific Search Space, USS) is individually set for each terminal, and the range of a common search space (CSS) is known to all terminals. UE-specific and common search spaces may overlap for a given terminal. In the case of a fairly small search space, since there is no remaining CCE when some CCE positions are allocated in the search space for a specific terminal, the base station may not find CCE resources for transmitting the PDCCH to all possible terminals in a given subframe. A UE-specific hopping sequence is applied to the starting position of the UE-specific search space in order to minimize the possibility that the above blocking is followed by the next subframe.

Table 3 shows the sizes of common and UE-specific search spaces.

<tables num="3"><table><tgroup cols="4"><colspec colnum="1" align="justify" colname="col1" colwidth="2243" /><colspec colnum="2" align="justify" colname="col2" colwidth="2489" /><colspec colnum="3" align="justify" colname="col3" colwidth="3000" /><colspec colnum="4" align="justify" colname="col4" colwidth="3058" /><tbody><row><entry align="justify" colname="col1">PDCCH format</entry><entry align="justify" colname="col2">Number of CCEs (n)</entry><entry align="justify" colname="col3">Number of candidates in common search space</entry><entry align="justify" colname="col4">Number of candidates in dedicated search space</entry></row><row><entry align="justify" colname="col1">0</entry><entry align="justify" colname="col2">1</entry><entry align="justify" colname="col3">-</entry><entry align="justify" colname="col4">6</entry></row><row><entry align="justify" colname="col1">1</entry><entry align="justify" colname="col2">2</entry><entry align="justify" colname="col3">-</entry><entry align="justify" colname="col4">6</entry></row><row><entry align="justify" colname="col1">2</entry><entry align="justify" colname="col2">4</entry><entry align="justify" colname="col3">4</entry><entry align="justify" colname="col4">2</entry></row><row><entry align="justify" colname="col1">3</entry><entry align="justify" colname="col2">8</entry><entry align="justify" colname="col3">2</entry><entry align="justify" colname="col4">2</entry></row></tbody></tgroup></table></tables>

In order to put the computational load according to the total number of blind decoding (BD) under control, the UE is not required to simultaneously search all defined DCI formats. In general, within the UE-specific search space, the UE always searches for formats 0 and 1A. Formats 0 and 1A have the same size and are distinguished by flags in the message. In addition, the UE may be required to receive an additional format (eg, 1, 1B or 2 according to the PDSCH transmission mode set by the base station). In the common search space, the UE searches formats 1A and 1C. In addition, the terminal may be configured to search for format 3 or 3A. Formats 3 and 3A have the same size as formats 0 and 1A, and can be distinguished by scrambling CRCs with different (common) identifiers, rather than UE-specific identifiers. The PDSCH transmission scheme according to the transmission mode and the information content of DCI formats are listed below.

<u>Transmission Mode (TM)</u>

Transmission mode 1: Transmission from single base station antenna port

Transmission mode 2: Transmission diversity

Transmission mode 3: open-loop spatial multiplexing

Transmission mode 4: Closed-loop spatial multiplexing

Transmission mode 5: Multi-user MIMO

Transmission mode 6: Closed-loop rank-1 precoding

Transmission mode 7: single-antenna port (port 5) transmission

Transmission mode 8: dual layer transmission (ports 7 and 8) or single-antenna port (port 7 or 8) transmission

Transmission mode 9: Transmission of up to 8 layers (ports 7 to 14) or single-antenna port (ports 7 or 8) transmission

<u>DCI format</u>

Format 0: resource grant for PUSCH transmission (uplink)

Format 1: Resource allocation for single codeword PDSCH transmission (transmission modes 1, 2 and 7)

Format 1A: Compact signaling of resource allocation for single codeword PDSCH (all modes)

Format 1B: Compact resource allocation for PDSCH (mode 6) using rank-1 closed-loop precoding

Format 1C: very compact resource allocation for PDSCH (eg, paging/broadcast system information)

Format 1D: Compact resource allocation for PDSCH (mode 5) using multi-user MIMO

Format 2: Resource allocation for PDSCH (mode 4) of closed-root MIMO operation

Format 2A: resource allocation for PDSCH (mode 3) of open-loop MIMO operation

Format 3/3A: Power control command with 2-bit/1-bit power adjustment value for PUCCH and PUSCH

5 illustrates an EPDCCH. EPDCCH is a channel additionally introduced in LTE-A.

Referring to FIG. 5 , a PDCCH (for convenience, legacy PDCCH, L-PDCCH) according to the existing LTE may be allocated to the control region (refer to FIG. 4 ) of the subframe. In the drawing, the L-PDCCH region means a region to which the L-PDCCH can be allocated. Meanwhile, a PDCCH may be additionally allocated in a data region (eg, a resource region for PDSCH). The PDCCH allocated to the data region is referred to as an EPDCCH. As shown, by additionally securing control channel resources through the EPDCCH, scheduling constraints due to the limited control channel resources of the L-PDCCH region can be alleviated. Like L-PDCCH, EPDCCH carries DCI. For example, the EPDCCH may carry downlink scheduling information and uplink scheduling information. For example, the UE may receive an EPDCCH and may receive data/control information through a PDSCH corresponding to the EPDCCH. In addition, the UE may receive the EPDCCH and transmit data/control information through the PUSCH corresponding to the EPDCCH. Depending on the cell type, the EPDCCH/PDSCH may be allocated from the first OFDM symbol of the subframe. Unless otherwise specified, in the present specification, PDCCH includes both L-PDCCH and EPDCCH.

6 illustrates the structure of an uplink subframe used in LTE (-A).

Referring to FIG. 6 , a subframe 500 consists of two 0.5ms slots 501 . Assuming the length of a Normal Cyclic Prefix (CP), each slot consists of 7 symbols 502 and one symbol corresponds to one SC-FDMA symbol. A resource block (RB) 503 is a resource allocation unit corresponding to 12 subcarriers in the frequency domain and one slot in the time domain. The structure of the uplink subframe of LTE(-A) is largely divided into a data region 504 and a control region 505 . The data area means a communication resource used for transmitting data such as voice and packets transmitted to each terminal, and includes a Physical Uplink Shared Channel (PUSCH). The control region means a communication resource used to transmit an uplink control signal, for example, a downlink channel quality report from each terminal, a reception ACK/NACK for a downlink signal, an uplink scheduling request, and the like, and PUCCH (Physical Uplink). control channels). A sounding reference signal (SRS) is transmitted through the last SC-FDMA symbol located on the time axis in one subframe. SRSs of several terminals transmitted through the last SC-FDMA of the same subframe can be distinguished according to frequency positions/sequences. The SRS is used to transmit the uplink channel state to the base station, and is transmitted periodically according to the subframe period/offset set by the higher layer (eg, the RRC layer), or transmitted aperiodically according to the request of the base station.

7 illustrates an uplink-downlink frame timing relationship.

7, the transmission of the uplink radio frame i is more than the corresponding downlink radio frame (N_TA+N_TAoffset)*T_sStarts before seconds. For LTE system, 0N_TA 20512, and N in FDD_TAoffset= 0, N in TDD_TAoffset=624. N_TAoffset The value is a value recognized in advance by the base station and the terminal. N through the timing advance command in the random access process_TAWhen this is indicated, the UE adjusts the transmission timing of the UL signal (eg, PUCCH/PUSCH/SRS) through the above equation. UL transmission timing is 16T_sis set as a multiple of The timing advance command indicates a change in UL timing based on the current UL timing. Timing advance command in random access response (T_A) is an 11-bit T as_Ais 0,1,2, ,1282 and the timing adjustment value (NTA) is N_TA=T_AIt is given as *16. Otherwise, the timing advance command (T_A) is a 6-bit T_Ais 0,1,2, represents a value of ,63 and the timing adjustment value (N_TA) is N_{TA, new}=N_{TA, old}+(T_A-31)*16 is given. The timing advance command received in subframe n is applied from subframe n+6. In the case of FDD, as shown, the transmission time of the UL subframe n is advanced based on the start time of the DL subframe n. On the other hand, in the case of TDD, the transmission time of the UL subframe n is advanced based on the end time of the DL subframe n+1 (not shown).

Next, HARQ (Hybrid Automatic Repeat reQuest) will be described. When a plurality of terminals having data to be transmitted in uplink/downlink in a wireless communication system exist, the base station selects a terminal to transmit data every transmission time interval (TTI) (eg, subframe). In a multi-carrier and similar operating system, the base station selects terminals to transmit data in uplink/downlink for each TTI, and also selects a frequency band used by the corresponding terminal for data transmission.

When described with reference to the uplink, the terminals transmit a reference signal (or pilot) in the uplink, and the base station uses the reference signal transmitted from the terminals to determine the channel state of the terminals, and in each unit frequency band for each TTI. Select terminals to transmit data in uplink. The base station notifies the terminal of this result. That is, the base station transmits an uplink assignment message for sending data using a specific frequency band to a terminal scheduled for uplink at a specific TTI. The uplink assignment message is also referred to as a UL grant. The terminal transmits data in uplink according to the uplink assignment message. The uplink assignment message may include UE ID (UE Identity), RB assignment information, Modulation and Coding Scheme (MCS), Redundancy Version (RV) version, New Data indication (NDI), and the like.

In the case of the synchronous non-adaptive HARQ scheme, the retransmission time is systematically promised (eg, 4 subframes after the NACK reception time). Therefore, the UL grant message sent by the base station to the terminal needs only to be transmitted during initial transmission, and subsequent retransmission is performed by the ACK/NACK signal (eg, PHICH signal). On the other hand, in the case of the asynchronous adaptive HARQ scheme, since retransmission times are not promised to each other, the base station must send a retransmission request message to the terminal. In addition, since the frequency resource or MCS for retransmission varies for each transmission time, the retransmission request message may include UE ID, RB allocation information, HARQ process ID/number, RV, and NDI information.

8 illustrates UL HARQ operation in an LTE(-A) system. In the LTE (-A) system, the UL HARQ scheme uses synchronous non-adaptive HARQ. When using 8-channel HARQ, the HARQ process number is given as 0~7. One HARQ process operates per TTI (eg, subframe). Referring to FIG. 8 , the base station 110 transmits a UL grant to the terminal 120 through the PDCCH (S600). The terminal 120 transmits uplink data to the base station S110 using the RB and MCS designated by the UL grant after 4 subframes (eg, subframe 4) from the time when the UL grant is received (eg, subframe 0). It transmits (S602). The base station 110 decodes the uplink data received from the terminal 120 and then generates ACK/NACK. When decoding of the uplink data fails, the base station 110 transmits a NACK to the terminal 120 (S604). The terminal 120 retransmits uplink data 4 subframes after receiving the NACK (S606). The same HARQ processor is responsible for initial transmission and retransmission of uplink data (eg, HARQ process 4). ACK/NACK information may be transmitted through PHICH.

9 illustrates a carrier aggregation (CA) communication system.

Referring to FIG. 9 , a wider uplink/downlink bandwidth may be supported by collecting a plurality of uplink/downlink component carriers (CCs). Each of the CCs may be adjacent to or non-adjacent to each other in the frequency domain. The bandwidth of each component carrier may be independently determined. Asymmetric carrier aggregation in which the number of UL CCs and the number of DL CCs are different is also possible. Meanwhile, the control information may be set to be transmitted/received only through a specific CC. This specific CC may be referred to as a primary CC, and the remaining CCs may be referred to as a secondary CC. For example, when cross-carrier scheduling (or cross-CC scheduling) is applied, the PDCCH for downlink allocation is transmitted on DL CC#0, and the corresponding PDSCH is transmitted on DL CC#2. have. The term "component carrier" may be replaced with other equivalent terms (eg, carrier, cell, etc.).

For cross-CC scheduling, a carrier indicator field (CIF) is used. Configuration for the presence or absence of a CIF in the PDCCH may be semi-statically enabled by higher layer signaling (eg, RRC signaling) in a UE-specific (or UE group-specific manner) manner. The basics of PDCCH transmission may be summarized as follows.

CIF disabled (disabled): A PDCCH on a DL CC allocates a PDSCH resource on the same DL CC and a PUSCH resource on a single linked UL CC.

No CIF

CIF enabled (enabled): The PDCCH on the DL CC may allocate a PDSCH or PUSCH resource on one DL/UL CC among a plurality of merged DL/UL CCs by using the CIF.

LTE DCI format extended to have CIF

- CIF (if set) is a fixed x-bit field (eg x=3)

- CIF (if set) position is fixed regardless of DCI format size

In the presence of CIF, the base station may allocate a monitoring DL CC (set) to reduce BD complexity at the terminal side. For PDSCH/PUSCH scheduling, the UE may perform detection/decoding of the PDCCH only in the corresponding DL CC. In addition, the base station may transmit the PDCCH only through the monitoring DL CC (set). The monitoring DL CC set may be set in a UE-specific, UE-group-specific or cell-specific manner.

10 illustrates scheduling when a plurality of carriers are merged. It is assumed that three DL CCs are merged. It is assumed that DL CC A is configured as a PDCCH CC. DL CCs A to C may be referred to as serving CCs, serving carriers, serving cells, and the like. When CIF is disabled, each DL CC may transmit only PDCCH scheduling its own PDSCH without CIF according to the LTE PDCCH rule (non-cross-CC scheduling). On the other hand, when CIF is enabled by UE-specific (or UE-group-specific or cell-specific) higher layer signaling, a specific CC (eg, DL CC A) uses the CIF to schedule the PDSCH of DL CC A. In addition to the PDCCH, a PDCCH scheduling a PDSCH of another CC may also be transmitted (cross-CC scheduling). On the other hand, PDCCH is not transmitted in DL CC B/C.

As more and more communication devices require a larger communication capacity, efficient use of a limited frequency band in the next wireless communication system becomes an increasingly important requirement. Basically, the frequency spectrum is divided into a licensed band and an unlicensed band. Licensed bands include frequency bands occupied for specific uses. For example, the licensed band includes a frequency band allocated by the government for cellular communication (eg, LTE frequency band). An unlicensed band is a frequency band occupied for public use and is also referred to as a license-free band. Unlicensed bands can be used by anyone without permission or notification as long as they meet the conditions for radio wave regulation. The unlicensed band is distributed or designated for anyone to use at a close distance, such as in a specific area or building, within the output range that does not impede communication of other wireless stations, and is widely used for wireless remote control, wireless power transmission, and wireless LAN (WiFi). have.

Cellular communication systems such as LTE systems are also under consideration for using unlicensed bands (eg, 2.4 GHz, 5 GHz bands) used by existing WiFi systems for traffic offloading. Basically, the unlicensed band assumes a method of wireless transmission and reception through contention between each communication node, so each communication node performs Channel Sensing (CS) before transmitting a signal to ensure that other communication nodes do not transmit signals. asking for confirmation. This is called CCA (Clear Channel Assessment), and the base station or terminal of the LTE system may also need to perform CCA for signal transmission in an unlicensed band. For convenience, the unlicensed band used in the LTE-A system is referred to as an LTE-U band/band. In addition, when the base station or the terminal of the LTE-A system transmits a signal, other communication nodes such as WiFi should also perform CCA so as not to cause interference. For example, in the WiFi standard (801.11ac), the CCA threshold is defined as -62 dBm for a non-WiFi signal and -82 dBm for a WiFi signal. Therefore, when a signal other than WiFi is received with power of -62 dBm or more, the STA (Station)/AP (Access Point) does not transmit the signal in order not to cause interference. In the WiFi system, the STA/AP may perform CCA and signal transmission if it does not detect a signal equal to or greater than the CCA threshold of 4us or more.

11 illustrates carrier aggregation of a licensed band and an unlicensed band. 11, under the carrier aggregation situation of licensed band (hereinafter, LTE-A band, L-band) and unlicensed band (hereinafter, LTE-U band, U-band), the base station transmits a signal to the terminal or the terminal It can transmit a signal to the base station. Here, the center carrier or frequency resource of the licensed band may be interpreted as PCC or PCell, and the center carrier or frequency resource of the unlicensed band may be interpreted as SCC or SCell.

12-13 illustrate a method of occupying a resource within an unlicensed band. In order for the base station and the terminal to communicate in the LTE-U band, it must be able to occupy/secure the corresponding band for a specific time period through contention with other communication (eg, WiFi) systems unrelated to LTE-A. For convenience, the time period occupied / secured for cellular communication in the LTE-U band is referred to as a Reserved Resource Period (RRP). There may be several methods to secure the RRP interval. For example, other communication system devices, such as WiFi, may transmit a specific occupancy signal within the RRP section to recognize that the wireless channel is busy. For example, in order to continuously transmit a signal above a specific power level during the RRP period, the base station may continuously transmit RS and data signals within the RRP period. If the base station has previously determined the RRP section to be occupied on the LTE-U band, the base station may allow the terminal to maintain the communication transmission/reception link during the indicated RRP section by notifying the terminal in advance. As a method of notifying the UE of RRP interval information, a method of delivering RRP time interval information through another CC (eg, LTE-A band) connected in the form of carrier aggregation is possible.

As an example, it is possible to set an RRP section consisting of M consecutive SFs. Alternatively, one RRP section may be set to a discontinuous SF set (not shown). Here, the M value and the M SF uses may be informed by the base station to the terminal in advance through higher layer (eg, RRC or MAC) signaling (using PCell) or a physical control/data channel. The start time of the RRP period may be periodically set by higher layer (eg, RRC or MAC) signaling. In addition, when you want to set the RRP start point to SF #n, the start point of the RRP interval can be specified in SF #n or through physical layer signaling (eg, (E)PDCCH) in SF #(nk). . k is a positive integer (eg 4).

RRP may be configured such that the SF boundary and SF number/index are configured to match the PCell (hereinafter, aligned-RRP) (FIG. 12), or the SF boundary or SF number/index is supported up to a form that does not match the PCell ( Hereinafter, floating-RRP (FIG. 13). In the present invention, the coincidence of SF boundaries between cells may mean that the interval between SF boundaries of two different cells is less than or equal to a specific time (eg, CP length, or X us (X0)). In addition, in the present invention, the PCell may refer to a cell referred to to determine the SF (and/or symbol) boundary of the UCell in terms of time (and/or frequency) synchronization.

As another example of operation in an unlicensed band operating in a contention-based random access scheme, the base station may first perform carrier sensing before data transmission/reception. If it is determined that the current channel state of the SCell is idle, the base station transmits a scheduling grant (eg, (E)PDCCH) through the PCell (LTE-A band) or the SCell (LTE-U band) and attempts data transmission/reception on the SCell can do. For convenience, a serving cell (eg, PCell, SCell) operating in a licensed band is defined as an LCell, and a center frequency of the LCell is defined as a (DL/UL) LCC. A serving cell (eg, SCell) operating in an unlicensed band is defined as a UCell, and a center frequency of the UCell is defined as (DL/UL) UCC. In addition, the case where the UCell is scheduled from the same cell and the case where the UCell is scheduled from another cell (eg, PCell) are referred to as self-CC scheduling and cross-CC scheduling, respectively.

<b><u>Example: Signal transmission and reception in LTE Licensed Assisted Access (LAA)</u></b>

A single-SF scheduling scheme for scheduling one DL/UL data channel (eg, PDSCH/PUSCH) through which each DL/UL grant DCI is transmitted through a single DL/UL SF is applied to the existing LTE system. On the other hand, in a system after LTE-A, one DL/UL grant DCI simultaneously schedules a plurality of DL/UL data channels transmitted through a plurality of DL/UL SFs in order to reduce DCI overhead involved in data scheduling. Application of the SF scheduling method may be considered. The need and advantages of the multi-SF scheduling scheme may be further emphasized in terms of system operation (eg, UL scheduling) on an unlicensed band (ie, U-band). A brief summary of this is as follows.

1) In the case of self-CC scheduling for UCell, for flexible duplexing operation and DL/UL resource configuration, a plurality of UL SFs can be scheduled when a DL radio channel is acquired once (based on CCA for UCell). It can be advantageous to be able to

2) From the point of view of one UE (based on CCA for UCell), it may be advantageous to be able to occupy a plurality of UL SFs when a UL radio channel is acquired once. That is, it may be advantageous to schedule a plurality of consecutive SFs with one UL grant DCI for one UE.

3) When only the single-SF scheduling scheme is assumed, compared to the number of UL grant DCIs transmitted by the base station, the number of UEs that transmit PUSCH after successful CCA may be small. Therefore, it may be more necessary to reduce DCI overhead for the UCell.

4) When the UCell is configured to be cross-CC scheduled from the TDD LCell, it may be advantageous to apply the multi-SF scheduling scheme in order to use all of the UCell resources as UL SFs.

On the other hand, unlike the existing LCell in which the DL/UL SF is configured continuously or periodically, the UCell has a characteristic in which the DL/UL SF is configured aperiodically/opportunistically according to the CCA result of the base station/terminal. Therefore, for UCell UL, not a synchronous HARQ scheme supporting PHICH-based non-adaptive automatic retransmission, but an asynchronous HARQ scheme performing only UL grant-based adaptive retransmission without PHICH reference. This can be applied. In the synchronous HARQ method, a specific (periodic) UL SF set constitutes one UL HARQ process, and the Redundancy Version (RV) is also automatically determined according to the SF number (with a predefined pattern) without separate signaling. On the other hand, in the asynchronous HARQ scheme, as in the conventional LCell DL, the UL HARQ process ID and RV may be directly signaled through the UL grant DCI.

Hereinafter, a multi-SF scheduling method for reducing scheduling (UL grant) DCI overhead accompanying UL data transmission on a UCell is proposed. Specifically, in the present invention, a content configuration in a UL grant DCI for multi-SF scheduling and a transmission/operation method for the corresponding DCI are presented, and HARQ in addition to the UL grant DCI applied to the existing LCell UL in consideration of the asynchronous HARQ operation Consider including ID and RV. The present invention provides not only asynchronous HARQ-based UL data scheduling for UCell, but also asynchronous HARQ-based DL/UL data scheduling for any cell (including LCell/UCell without distinction of operating bands) and synchronous HARQ-based UL data scheduling can be applied similarly. In addition, the present invention may be applied to an LTE-U system (or LTE LAA system) that opportunistically operates in an unlicensed band based on carrier sensing. The present invention may consider a CA situation between a PCell operating in a licensed band (ie, L-band) and an SCell operating in an unlicensed band (ie, U-band).

Table 4 is an example of a UL grant DCI (eg, DCI format 0) applied to the existing LCell UL.

<tables num="4"><table><tgroup cols="3"><colspec colnum="1" align="justify" colname="col1" colwidth="680" /><colspec colnum="2" align="justify" colname="col2" colwidth="6625" /><colspec colnum="3" align="justify" colname="col3" colwidth="2507" /><tbody><row><entry align="justify" colname="col1"></entry><entry align="justify" colname="col2">information field</entry><entry align="justify" colname="col3">bit(s)</entry></row><row><entry align="justify" colname="col1">(1)</entry><entry align="justify" colname="col2">Flag to distinguish between Format0/Format1A</entry><entry align="justify" colname="col3">1</entry></row><row><entry align="justify" colname="col1">(2)</entry><entry align="justify" colname="col2">hopping flag</entry><entry align="justify" colname="col3">1</entry></row><row><entry align="justify" colname="col1">(3)</entry><entry align="justify" colname="col2">Resource block allocation and hopping resource allocation</entry><entry align="justify" colname="col3"><img file="KR20180098667A_D0001.tif" /></entry></row><row><entry align="justify" colname="col1">(4)</entry><entry align="justify" colname="col2">Modulation and coding scheme and redundancy Version (MCS and RV)</entry><entry align="justify" colname="col3">5</entry></row><row><entry align="justify" colname="col1">(5)</entry><entry align="justify" colname="col2">New Data Indicator (NDI)</entry><entry align="justify" colname="col3">1</entry></row><row><entry align="justify" colname="col1">(6)</entry><entry align="justify" colname="col2">TPC command for scheduled PUSCH </entry><entry align="justify" colname="col3">2</entry></row><row><entry align="justify" colname="col1">(7)</entry><entry align="justify" colname="col2">Cyclic shift for DMRS (Demodulation Reference Signal)</entry><entry align="justify" colname="col3">3</entry></row><row><entry align="justify" colname="col1">(8)</entry><entry align="justify" colname="col2">UL Index (TDD)</entry><entry align="justify" colname="col3">2</entry></row><row><entry align="justify" colname="col1">(9)</entry><entry align="justify" colname="col2">CQI request (request)</entry><entry align="justify" colname="col3">1</entry></row></tbody></tgroup></table></tables>

The flag field is an information field for distinguishing between format 0 and format 1A. That is, DCI formats 0 and 1A have the same payload size and are distinguished by a flag field. The bit size of the resource block allocation and hopping resource allocation fields may vary according to a hopping PUSCH or a non-hoppping PUSCH. The resource block allocation and hopping resource allocation fields for non-hopping PUSCH are<img file="KR20180098667A_D0002.tif" /> The bit is provided for resource allocation of the first slot in the uplink subframe. N^UL_RBis the number of resource blocks included in the uplink slot, and is dependent on the uplink transmission bandwidth set in the cell. Accordingly, the payload size of DCI format 0 may vary according to the uplink bandwidth. DCI format 1A includes an information field for PDSCH allocation, and the payload size of DCI format 1A may also vary according to a downlink bandwidth. DCI format 1A provides a reference information bit size for DCI format 0. Therefore, when the number of information bits of DCI format 0 is less than the number of information bits of DCI format 1A, '0' is '0' in DCI format 0 until the payload size of DCI format 0 becomes equal to the payload size of DCI format 1A. is added The added '0' is filled in a padding field of the DCI format.

For convenience, first, DCI content for UL data transmission is defined as follows.

1) RA (Resource Allocation): Resource (eg, RB) allocation information (eg, N bits) used for data (eg, UL-SCH transport block) transmission

2) MCS: modulation/coding method used for data transmission (eg, 5 bits)

3) DMRS CS: CS and orthogonal cover code (OCC) information (eg, 3 bits) for DMRS of a UL data channel (eg, PUSCH)

4) TPC: Power information (eg, 2 bits) added to UL data channel (eg, PUSCH) transmission

5) CSI (Channel State Information) request: indicates whether aperiodic CSI feedback is transmitted (eg, 1 to 3 bits)

6) SRS request: indicates whether aperiodic SRS signal is transmitted (eg, 1 bit)

7) NDI: Indicates whether new data is transmitted or whether it is retransmission of previously received data (eg, 1 bit)

8) HARQ ID: HARQ process ID/number corresponding to data transmission (eg 3~4 bits)

9) RV: Redundancy version information used for data transmission (eg 2 bits)

10) DAI (Downlink Assignment Index): indicates the total number of PDSCHs (or PDCCHs) scheduled through multiple DL SFs (for convenience, bundling window) linked to a single UL SF (eg, 2 bits)

In the following description, multi-SF means a maximum subframe period in which multi-SF scheduling can be performed according to context, or a sub to which multi-SF scheduling is actually applied within the maximum subframe period in which multi-SF scheduling is performed. It may mean a frame period. Unless otherwise specified, multi-SF may mean a subframe period to which multi-SF scheduling is actually applied. The multi-SF may be a continuous SF.

<b>(1) Method 1</b>

For multi-SF scheduling (UL grant) DCI design, DCI content may be classified into three content types. In addition, information (hereinafter, Nsf) indicating the number/interval of SFs to which scheduling according to the DCI is applied may be additionally signaled in the multi-SF grant DCI.

1) Content type 1: Information commonly (samely) applied to multi-SF

A. Only one value is signaled within the multi-SF grant DCI, and the single value is applied equally to the entire multi-SF.

B. Yes, RA (N bits), MCS (5 bits), DMRS CS (3 bits), TPC (2 bits), etc.

2) Content type 2: Information that is applied only to one specific SF belonging to multi-SF (once)

A. Only one value is signaled within the multi-SF grant DCI, and the value is applied only to one specific SF belonging to the multi-SF.

B. Yes, CSI request (2 bits), SRS request (1 bit), DAI (2 bits), etc.

When CSI/SRS is transmitted only in one specific SF, if CCA fails in the corresponding SF, the UE loses a CSI/SRS transmission opportunity. Therefore, a method of transmitting CSI/SRS in each SF of multi-SF may also be considered. However, when CSI/SRS is transmitted in each SF of the multi-SF, the UE performs an SRS transmission operation in every SF of the multi-SF, even though a plurality of SRS transmissions are not required, so UL resources may be wasted. have. On the other hand, if CSI/SRS is transmitted only in a specific SF, even if CSI/SRS transmission fails due to CCA failure in the corresponding SF, the base station can re-request CSI/SRS transmission to the UE, so that only one specific SF belonging to multi-SF is transmitted. It is preferable to transmit CSI/SRS.

3) Content type 3: Information applied individually to each SF belonging to multi-SF

A. Signaled as many as the number of scheduling target SFs in the multi-SF grant DCI, and individually applied to each SF belonging to the multi-SF

B. Yes, NDI (1 bit), RV (2 bits), HARQ process ID (3 bits), etc.

Meanwhile, the multi-SF grant DCI may be configured to have the same size regardless of the number/interval of scheduling target SFs (ie, Nsf value). That is, the multi-SF grant DCI may be configured to have the same size for all Nsf values. As an example, the multi-SF grant DCI size may be set based on the DCI content configuration when the minimum Nsf value (eg, 1) is applied. Under these conditions, (1) the number/size of fields corresponding to content type 3 in the multi-SF grant DCI may be allocated proportionally to the Nsf value (that is, the larger the Nsf value, the greater the number/size of the fields) increase), (2) In the multi-SF grant DCI, the size of a field corresponding to content type 1/2 may be decreased as the Nsf value increases, or the corresponding field itself may be omitted. In other words, as the Nsf value increases (in the multi-SF grant DCI having a fixed size), the number/size of fields corresponding to content type 3 (eg, NDI, RV, HARQ ID) increases, whereas the content type The size of the field corresponding to 1/2 (eg, RA, MCS, DMRS CS, TPC, CSI request, SRS request) may be reduced or the corresponding field may be omitted. Based on this, the granularity (size of information unit)/number of contents type 1/2 value and/or the presence or absence of a corresponding field may vary according to the Nsf value (Approach 1).

As an example of the above process, it is assumed that the field sizes of the CSI request and the HARQ ID are 2 bits and 3 bits, respectively, and the multi-SF grant DCI size is set to (N + 19) bits based on Nsf = 1 Consider a situation. can In this case, content type 3 may be allocated with NDI(1) + RV(2) + HARQ ID(3) = 6 bits. Numbers in parentheses indicate the number of bits. In this situation, if Nsf = 2, content type 3 is NDI(2) + RV(4) + HARQ ID(5 = ceiling(log)₂(₈C₂))) = 11 bits may be allocated. Here, the HARQ ID field may be allocated with the minimum number of bits capable of expressing the number of Nsf=2 pieces selected from among the total N=8 HARQ IDs. When Nsf = 2, the content type 3 field size increases by 5 bits compared to when Nsf = 1, so when Nsf = 1, content type 1/2 = RA(N) + MCS(5) + DMRS CS(3) + TPC(2) + CSI request(2) + SRS request(1) = (N + 13) bits minus 5 bits (N + 8) bits to content type 1/2 field size when Nsf = 2 can be assigned For example, RA(N - 2) + MCS(5 - 1) + DMRS CS(3 - 1) + TPC(2) + CSI request (2 - 1) + SRS request (1) = (N + 8) A content type 1/2 field when Nsf = 2 can be configured with bits. In this case, the granularity of the RA may be increased (coarse) (eg, the size of the RB group may be increased), or the number of MCS and DMRS CS values may be reduced. In the case of a CSI request, the number of DL cell combinations that can be indicated as a CSI feedback request target may decrease.

Additionally, in the same situation as above, if Nsf = 4, content type 3 is NDI(4) + RV(8) + HARQ ID(7 = ceiling(log)₂(₈C₄))) = 19 bits may be allocated. Since the content type 3 field size when Nsf = 4 is 13 bits longer than when Nsf = 1, we get N bits minus 13 bits from the content type 1/2 field size (N + 13) bits when Nsf = 1 When Nsf = 4, the content type 1/2 field size can be allocated. For example, RA(N - 6) + MCS(5 - 2) + DMRS CS(3 - 2) + TPC(2) + CSI request (2 - 2) + SRS request (1 - 1) = Nsf with N bits = 2, the content type 1/2 field can be configured. In this case, the granularity of the RA may be increased (more than in the case of Nsf = 2), or the number of MCS and DMRS CS values may be reduced (more than in the case of Nsf = 2). In addition, since fields are omitted in the case of CSI request and SRS request, aperiodic CSI/SRS transmission request may not be allowed through multi-SF grant DCI with Nsf = 4.

In a different way from the above, if the multi-SF grant DCI size is set based on the DCI content configuration when the maximum Nsf value (Nsf_max) (eg, 4 or 8) is applied, and another Nsf value (smaller than the maximum value) is applied DCI size can be set equally for all Nsf values by composing DCI content in multi-SF grant DCI and padding the remaining part with a specific bit (eg, 0) (Approach 2). That is, the DCI size is configured according to Nsf_max, and when another Nsf value (smaller than Nsf_max) is applied, only information corresponding to the Nsf value is used in the DCI. Considering the case where the multi-SF is a continuous SF, setting the multi-SF grant DCI size according to Nsf_max may be a waste of resources, but by maintaining the size of each DCI content constant regardless of the Nsf value, the It is possible to prevent mismatch in the size of DCI content between terminals. In addition, when the size of the DCI content is kept constant regardless of the Nsf value, the granularity (size of the information unit)/number of pieces of the content type 1/2 value and/or the presence or absence of a corresponding field are all possible Nsf values. Since it remains the same for the value, it is possible to prevent scheduling constraints/inefficiencies according to the Nsf value. Assuming the same situation as before, for example, for all Nsf values, content type 1/2 is RA(N) + MCS(5) + DMRS CS(3) + TPC(2) + CSI request(2) + SRS Content type 3 when request(1) = (N + 13) bits are equally allocated and maximum value Nsf = 4 is NDI(4) + RV(8) + HARQ ID(7 = ceiling(log)₂(₈C₄))) = 19 bits. Based on this, the multi-SF grant DCI size may be set to (N + 32 = N + 13 + 19) bits. In this situation, when Nsf = 2, the content type 3 field size may be allocated to 11 bits, which is 8 bits less than when Nsf = 4, and the corresponding 8 bits in the multi-SF grant DCI may be padded with zeros. That is, the DCI size is determined based on the size of the content type 3 field when Nsf_max is Nsf_max, and when another Nsf value (smaller than Nsf_max) is applied, content type 3 information having a size corresponding to Nsf in DCI is used. In addition, the content type 3 field size in the case of Nsf = 1 may be allocated to 6 bits, 13 bits reduced from that in the case of Nsf = 4, and the corresponding 13 bits in the multi-SF grant DCI may be padded with zeros.

As another method of Approach 2, in the state where the DCI size is set based on the maximum Nsf value and DCI content corresponding to the maximum Nsf value is configured (eg, each of the Nsf SFs has an information field corresponding to content type 3 individually) and Nsf content type 3 information fields in total) and content type 3 information may be identically set for a plurality of SFs. Through this, by notifying the Nsf implicitly, multi-SF scheduling corresponding to the Nsf value smaller than the maximum value can be applied without separately signaling the Nsf in the multi-SF grant DCI. That is, the terminal may determine the number/section of SFs to which multi-SF scheduling is to be applied, based on the number of SFs to which content type 3 information is identically set.

For example, when all or a specific part of content type 3 information (eg, including at least HARQ ID) is set identically for N (&gt;1) SFs, one specific one (eg, first) of the N SFs PUSCH transmission based on the corresponding content type 3 information may be performed only for SFs, and PUSCH transmission may be omitted for the remaining (N - 1) SFs. As an additional example, when NDI is set to a different value for N SFs and the same value is set for all or a specific part (eg, including at least HARQ ID) of content type 3 information other than the corresponding NDI, the N SFs PUSCH transmission based on the corresponding content type 3 information may be performed only for one specific (eg, first) SF among them, and PUSCH transmission may be omitted for the remaining (N - 1) SFs.

As another example, when MCS is set/configured as content type 3, PUSCH transmission may be omitted through an SF corresponding to a specific MCS value or a combination of a specific MCS value and a specific RV value. As an additional example, when both MCS and RA are set/configured as content type 3, a combination of a specific MCS value and a specific RA (eg, a specific number of RB(G) and/or a specific RB(G) index) or a specific MCS value and PUSCH transmission may be omitted through the SF corresponding to the combination of the specific RA and the specific RV value.

As another method, the multi-SF grant DCI size is set based on the DCI content configuration when a specific Nsf value is applied, and when the Nsf value is greater than a specific Nsf value, Approach 1 is applied, and the Nsf value is a specific Nsf value In the smaller case, Approach 2 can be applied (Approach 3). As another method, in a state in which a multi-SF grant DCI (having a different size) is configured for each Nsf value without DCI reduction (through Approach 1) or bit padding (via Approach 2), the multi-SF grant An (E)PDCCH search space (SS) for blind decoding (BD) for DCI may be allocated differently for each Nsf value. In this case, without separate DCI signaling for the Nsf value, the UE can determine the Nsf value linked/configured to the SS resource/region in which the multi-SF grant DCI is detected as the number/interval of SFs to which the DCI-based multi-SF scheduling is to be applied. have. As another method, in a state in which multi-SF grant DCI (with different sizes) is configured by dividing all Nsf values into a plurality of sets and applying Approach 1/2/3 to each set of Nsf values, the multi-SF grant DCI SS for BD may be allocated differently for each Nsf value set. As an example, in a state in which the existing single-SF grant DCI corresponding to Nsf = 1 and the multi-SF grant DCI (approach 1/2/3 applied) corresponding to Nsf &gt; 1 (having a size different from this) are configured, single SS for BD of -SF grant DCI and multi-SF grant DCI may be allocated differently.

Additionally, in order to support TDM between PUSCH transmissions of different terminals and TDM between PUSCH transmissions (based on different RB and/or MCS and/or TBS (Transport Block Size)) of one terminal, (i) multi-SF Information on the first SF to which scheduling is to be applied, or (ii) the first SF belonging to the scheduling target multi-SF (ie, the first SF to which scheduling is to be applied within the multi-SF) may be signaled through the multi-SF grant DCI (hereinafter referred to as the multi-SF grant DCI). , (i) to (ii) are collectively referred to as first-SF). Alternatively, in a state in which multi-SF grant DCI is configured for each first-SF designated in advance (without separate DCI signaling for first-SF), SS for BD for multi-SF grant DCI is allocated differently for each first-SF can do. That is, the UE may determine the first-SF linked/configured to the SS resource/region in which the DCI is detected as the first SF of the multi-SF to which the DCI-based scheduling is to be applied. In addition, a plurality of multi-SF grant DCIs corresponding to different first-SFs may be configured to be simultaneously transmitted/detected through one DL SF.

On the other hand, when RA is considered as content type 3, the RA field (size) in DCI may be configured/allocated in a form including resource allocation information for a BW having a size in which the system BW (bandwidth) is extended by an Nsf value. As an example, when the system BW is an RB of N and Nsf = K, the RA field (size) including resource allocation information for the extended BW corresponding to a total of K*N RBs is configured/allocated in the multi-SF grant DCI. can be As a specific example, the resource allocated in the RB section from the (k-1)*N+1th RB to the k*Nth RB on the corresponding RA field is a PUSCH resource allocated to the kth SF in the scheduled multi-SF. can be decided. By doing so, the RA field size can be reduced compared to a case in which K RA fields (sizes) including resource allocation information for BWs corresponding to N RBs are configured/allocated. In addition, when MCS is considered as content type 3 (in the entire multi-SF), the MCS index of the original granularity is allocated only to the first-SF, and the index offset is applied to the MCS information allocated to the first-SF for the remaining SFs. A field (size) in DCI may be configured/allocated. As an example, if the original MCS consists of N bits and Nsf = K, an N-bit MCS index is allocated to only one first-SF, and an L-bit index offset (L &lt; N) for the remaining (K - 1) SFs. In the form of allocation, the MCS field (size) may be configured/allocated in the multi-SF grant DCI. The MCS index applied to the remaining (K - 1) SFs may be obtained by applying an L-bit index offset (L &lt; N) to the corresponding N-bit MCS index.

As another method, a method of performing only scheduling for transmission of new data (rather than retransmission of previously received data) may be considered through the multi-SF scheduling method. Retransmission can be performed through the existing single-SF scheduling method. In this case, in multi-SF grant DCI, NDI is individually configured/indicated for each SF, whereas in RV, field configuration (signaling through this) itself may be omitted. Accordingly, in the case of multi-SF grant DCI-based scheduling, a preset specific RV value (eg, initial value 0) may be applied. In addition, it is also possible to indicate/apply the same single NDI value to the entire multi-SF by considering NDI as content type 1.

<b>(2) Method 2</b>

Method 1 presents a multi-SF grant DCI configuration method of a single size considering the variation in the number/interval of the SFs to be scheduled, and enables multi-SF scheduling support for different SFs/intervals (ie, Nsf values). However, it may be somewhat inefficient in terms of scheduling accuracy/overhead due to DCI granularity change according to the Nsf value and bit padding processing. Accordingly, a multi-SF scheduling method based on partial DCI transmission capable of improving scheduling accuracy/overhead without increasing BD for DCI is proposed.

In this method, the multi-SF grant DCI for multi-SF scheduling basically consists of two partial DCIs. Channel encoding is individually performed on each partial DCI, and each partial DCI may be transmitted through different control channel resources (eg, (E)CCE). Specifically, the first partial DCI (hereinafter, partial DCI-1) may include Nsf information, content type 1/2, and content type 3 for one first-SF, and the second partial DCI (hereinafter, partial DCI-) 2) may include content type 3 for the remaining SFs except for the first-SF (in multi-SF). Payload sizes of the two partial DCIs may be set differently. For example, partial DCI-1 may have a fixed payload size, whereas partial DCI-2 may have a different payload size according to an Nsf value.

Meanwhile, a CRC may be individually generated/added for each partial DCI. For example, C-RNTI-based scrambling/masking may be applied to the CRC of the partial DCI-1 as before, whereas separate scrambling/masking may not be applied to the CRC of the partial DCI-2. In this case, the CRC lengths of the two partial DCIs may be set differently (eg, the CRC of the partial DCI-2 has a smaller length than the CRC of the partial DCI-1). In addition, information on the transmission resource of the partial DCI-2 may be determined through partial DCI-1 detection. For example, information on a resource through which partial DCI-2 is transmitted may be directly signaled through partial DCI-1 or determined in a form in which a specific offset is added to a transmission resource of partial DCI-1. When the transmission resource of partial DCI-1 consists of a plurality of resource units, the transmission resource information of partial DCI-2 is an index of a specific (eg, first) resource unit among a plurality of resource units constituting the transmission resource of DCI-1. may be determined in a form in which an offset is added to .

According to this method, the UE may first attempt to detect partial DCI-1 through BD, based on information (eg, Nsf) in partial DCI-1 and/or resources used for partial DCI-1 transmission ( By determining the payload size and/or transmission resource of the partial DCI-2), detection/decoding of the partial DCI-2 may be attempted. When both partial DCI-1 and corresponding partial DCI-2 are detected, the UE may combine information of partial DCI-1/2 and apply it to multi-SF. If only partial DCI-1 is detected and partial DCI-2 detection fails, the UE may operate to 1) apply partial DCI-1 only to first-SF, or 2) ignore partial DCI-1. On the other hand, when Nsf = 1, transmission/detection of the partial DCI-2 may be omitted, and an operation may be performed to apply the partial DCI-1 to the first-SF.

14 illustrates a UL transmission process according to the present invention.

Referring to FIG. 14 , the terminal may receive DCI (ie, multi-SF grant DCI) including UL scheduling information for a plurality of subframes from the base station (S1402). The multi-SF grant DCI may be configured based on Method 1 or 2. Thereafter, the UE may transmit a plurality of UL channels (eg, PUSCH) in a plurality of subframes according to the UL scheduling information. Here, the plurality of subframes means a maximum subframe period in which multi-SF scheduling can be performed, or a subframe period to which multi-SF scheduling is actually applied within the maximum subframe period in which multi-SF scheduling is performed. can Information (ie, Nsf) indicating the number/interval of a plurality of subframes may be included in the multi-SF grant DCI. The multi-SF grant DCI may include UL scheduling information for a plurality of subframes on the UCell. In addition, the multi-SF grant DCI may be received on a UCell or an LCell (eg, PCell). Further, the wireless communication system may include an LTE LAA-based wireless communication system.

<b>(3) Other issues</b>

When multi-SF scheduling is applied based on Method 1/2 or another method, the UL SF time point corresponding to the CSI request and the SRS request in the multi-SF grant DCI (which may correspond to content type 2) (eg, aperiodic) It is necessary to set the transmission time of the PUSCH including the CSI feedback or the transmission time of the aperiodic SRS signal). The UL SF timing corresponding to the CSI request and/or the SRS request in the multi-SF grant DCI is 1) first-SF (ie, the first SF in which UL transmission is scheduled), 2) in the multi-SF (multi-SF scheduling is It may be set to the last SF (eg, the last SF in which UL transmission is scheduled) or 3) the SF that succeeded in CCA for the first time (ie, the SF in which the UCell radio channel is determined to be empty). In the case of 3), since the SRS transmission time varies according to the CCA result, the possibility that SRS transmission and PUSCH transmission collide between terminals may increase. On the other hand, if the base station tries to configure DL SF transmission immediately after UL SF transmission in multi-SF is terminated, 1) may be preferable to 2) because CCA of the base station may fail due to SRS transmission.

15 illustrates an SRS transmission process according to the present invention.

Referring to FIG. 15 , the terminal may receive DCI (ie, multi-SF grant DCI) including UL scheduling information for a plurality of subframes from the base station (S1502). The multi-SF grant DCI may further include SRS request information. The multi-SF grant DCI may be configured based on Method 1 or 2. Thereafter, according to the indication of the SRS request information, the UE may transmit the SRS only once through a pre-designated subframe within a plurality of subframes (S1504). Here, the pre-designated subframe may include a first subframe in which UL transmission is scheduled or a last subframe in which UL transmission is scheduled within a plurality of subframes. Here, the plurality of subframes means a maximum subframe period in which multi-SF scheduling can be performed, or a subframe period to which multi-SF scheduling is actually applied within the maximum subframe period in which multi-SF scheduling is performed. can Information indicating the number/interval of a plurality of subframes (ie, Nsf) may be included in the multi-SF grant DCI. Meanwhile, the UE may perform a plurality of UL transmissions (eg, PUSCH transmission) in a plurality of subframes based on the UL scheduling information in the multi-SF grant DCI. In addition, the multi-SF grant DCI may include UL scheduling information for a plurality of subframes on the UCell, and the SRS may be transmitted on the UCell. In addition, the multi-SF grant DCI may be received on a UCell or an LCell (eg, PCell). Further, the wireless communication system may include an LTE LAA-based wireless communication system.

In addition, the UL SF time point to which the DAI value (which may correspond to content type 2) in the multi-SF grant DCI is applied (eg, the HARQ-ACK payload size transmitted through the PUSCH is determined based on the DAI value) 1) may be configured only with first-SF, or 2) may be configured with only SF in which HARQ-ACK transmission is first performed in multi-SF. The size of the HARQ-ACK payload transmitted through the PUSCH in the remaining UL SFs in the multi-SF may be determined as the maximum size (eg, the total number of DL SFs in the bundling window linked to the UL SF). As another method, in order to reduce DCI overhead, the configuration of the DAI field in the multi-SF grant DCI and DAI signaling through it may be omitted. Accordingly, the HARQ-ACK payload size transmitted through PUSCH in all UL SFs scheduled through multi-SF grant DCI may always be determined as the maximum size.

On the other hand, with respect to the TPC included in the multi-SF grant DCI, depending on whether accumulation is set (for the received TPC command), 1) When accumulation is enabled, the TPC is set to the first-SF only once. 2) When accumulation is disabled, the TPC may be operated to be applied to all SFs belonging to the scheduled multi-SF every time.

<b>(4) UCell scheduling</b>

Considering the self-CC scheduling situation in which the UCell performs UL PUSCH scheduling (UL grant DCI transmission for this) for the UCell operating based on CCA, even though the actual PDSCH scheduling is not required, the base station receives the UL grant It may be necessary to configure/secure a DL section for only DCI transmission (based on CCA). However, due to this, it may not be easy to configure a flexible and efficient DL/UL resource interval (eg, SF) on the UCell, and overall system performance may be deteriorated.

In consideration of this problem, a cell performing DL scheduling (DL grant transmission for this) for one UCell (ie, a DL scheduling cell) is set to one cell in the same way as before, while UL scheduling (UL grant for this) A cell (ie, UL scheduling cell) performing transmission) may consider a method of configuring a plurality of cells. Accordingly, the UE performs DL grant DCI detection on only one DL scheduling cell at one time point for UCell DL scheduling, whereas UL grant DCI detection on a plurality of UL scheduling cells at one time point for UCell UL scheduling simultaneously can operate to perform For example, two UL scheduling cells may be configured for one UCell. In this case, the two UL scheduling cells may be 1) configured as a corresponding UCell as a scheduling target and one LCell, or 2) may be configured as two different LCells.

Under the above setting, as another method for UL grant DCI detection, on which cell among a plurality of UL scheduling cells (scheduling target) to perform UL grant DCI detection for a UCell, the UCell (or PCell) transmitted on the A method of instructing the UE through specific signaling (eg, UE-common PDCCH) may be considered. In this case, the UE may operate to perform UL grant DCI detection for a corresponding UCell only on a UL scheduling cell indicated through specific signaling. When the UE fails to detect a specific signaling, 1) UL grant DCI detection is performed on the most recently indicated UL scheduling cell, or 2) UL grant DCI detection is performed on a (pre-specified) specific LCell among a plurality of UL scheduling cells. can do.

Additionally, it is also possible to configure one UL scheduling cell and a plurality of (eg, two) DL scheduling cells for one UCell (opposite to the above). When two DL scheduling cells are considered, the DL scheduling cell may be 1) configured with a corresponding UCell as a scheduling target and one LCell, or 2) may be configured with two different LCells. Meanwhile, the DL/UL scheduling cell configuration method of the present method is not limited to scheduling for the UCell, and can be generally applied to scheduling for any cell including the LCell.

16 illustrates a base station and a terminal that can be applied to the present invention.

Referring to FIG. 16 , the wireless communication system includes a base station (BS) 110 and a terminal (UE) 120 . When the wireless communication system includes a relay, the base station or the terminal may be replaced with the relay.

The base station 110 includes a processor 112 , a memory 114 , and a radio frequency (RF) unit 116 . The processor 112 may be configured to implement the procedures and/or methods proposed in the present invention. The memory 114 is connected to the processor 112 and stores various information related to the operation of the processor 112 . The RF unit 116 is coupled to the processor 112 and transmits and/or receives wireless signals. The terminal 120 includes a processor 122 , a memory 124 and a radio frequency unit 126 . The processor 122 may be configured to implement the procedures and/or methods proposed in the present invention. The memory 124 is connected to the processor 122 and stores various information related to the operation of the processor 122 . The RF unit 126 is coupled to the processor 122 and transmits and/or receives wireless signals.

The embodiments described above are those in which elements and features of the present invention are combined in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to configure embodiments of the present invention by combining some elements and/or features. The order of operations described in the embodiments of the present invention may be changed. Some features or features of one embodiment may be included in another embodiment, or may be replaced with corresponding features or features of another embodiment. It is obvious that claims that are not explicitly cited in the claims can be combined to form an embodiment or included as a new claim by amendment after filing.

In this document, embodiments of the present invention have been mainly described focusing on the signal transmission/reception relationship between the terminal and the base station. This transmission/reception relationship is equally/similarly extended to signal transmission/reception between a terminal and a relay or a base station and a relay. A specific operation described in this document to be performed by a base station may be performed by an upper node thereof in some cases. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including the base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), and an access point. In addition, the terminal may be replaced with terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, an embodiment of the present invention provides one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), a processor, a controller, a microcontroller, a microprocessor, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in the memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may transmit and receive data to and from the processor by various known means.

It is apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the characteristics of the present invention. Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

The present invention can be used in a terminal, a base station, or other equipment of a wireless mobile communication system.