WO2020167091A1 - Method and device for transmitting/receiving wireless signal in wireless communication system - Google Patents

Abstract

The present invention relates to a wireless communication system, and to a method and a device therefor, the method comprising the steps of: receiving, from a base station, a call message for calling a terminal in an idle state; on the basis of the received call message, transmitting a response message for receiving downlink data to the base station; and receiving the downlink data from the base station, wherein the call message includes information on a plurality of resources configured for the terminal in order for the transmission of the response message, and the response message is transmitted on the basis of a resource, among the plurality of resources, selected by the terminal.

Description

Method and apparatus for transmitting and receiving radio 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 wireless signals. The wireless communication system includes a NB-IoT (Narrowband Internet of Things)-based wireless communication system.

Wireless communication systems have been 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 capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems 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) system.

An object of the present invention is to provide a method and apparatus for efficiently performing a wireless signal transmission/reception process.

The technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description.

In a first aspect of the present invention, a method for transmitting and receiving a signal by a terminal in a wireless communication system includes receiving a message for calling a terminal in an idle state from a base station, based on the received message, downlink Including the step of transmitting a response message for receiving the link data to the base station, and receiving downlink data from the base station, the message for calling the terminal relates to a plurality of resources set to the terminal for transmission of the response message Information is included, and the response message may be transmitted based on a resource selected by the terminal among a plurality of resources.

In a second aspect of the present invention, a terminal operating in a wireless communication system includes a transceiver and a processor, and the processor transmits a message for calling the terminal in an idle state from the base station. It receives, and transmits a response message for receiving downlink data to the base station based on the received message, and receives downlink data from the base station, but the message for calling the terminal is a plurality of messages set to the terminal for transmission of the response message. It includes information on the resource of, and the response message may be transmitted based on a resource selected by the terminal among a plurality of resources.

In a third aspect of the present invention, an apparatus for a terminal includes at least one processor and at least one computer memory that is operably connected to the at least one processor, and when executed, causes the at least one processor to perform an operation. In the above operation, a message for calling a terminal in an idle state is received from the base station, a response message for receiving downlink data is transmitted to the base station based on the received message, and downlink from the base station Receiving data, but the message for calling the terminal includes information on a plurality of resources set in the terminal for transmission of a response message, and the response message may be transmitted based on a resource selected by the terminal among a plurality of resources. .

In a fourth aspect of the present invention, there is provided a computer-readable storage medium including at least one computer program that, when executed, causes the at least one processor to perform an operation, the operation being in an idle state. Receives a message for calling the terminal from the base station, transmits a response message for receiving downlink data to the base station based on the received message, and receives downlink data from the base station, but the message for calling the terminal is responded It includes information on a plurality of resources set to the terminal for transmission of the message, and the response message may be transmitted based on a resource selected by the terminal from among the plurality of resources.

In a fifth aspect of the present invention, a method of transmitting and receiving signals by a base station in a wireless communication system includes: transmitting a message for calling a terminal in an idle state to the terminal, and receiving downlink data by the terminal Receiving a response message for the terminal from the terminal, and transmitting downlink data to the terminal, the message for calling the terminal includes information on a plurality of resources set in the terminal for transmission of the response message, The response message may be transmitted based on a resource selected by the terminal among a plurality of resources.

In a sixth aspect of the present invention, a base station operating in a wireless communication system includes a transceiver and a processor, and the processor sends a message to the terminal to call the terminal in an idle state. The message for transmitting, and receiving a response message for the terminal to receive downlink data from the terminal, and for transmitting downlink data to the terminal, and for calling the terminal, relates to a plurality of resources set in the terminal for transmission of the response message. Information is included, and the response message may be transmitted based on a resource selected by the terminal among a plurality of resources.

The response message according to an embodiment may be transmitted through a resource selected based on information on channel quality between a terminal and a base station among a plurality of resources.

The information on the channel quality between the terminal and the base station according to an embodiment may include a Coverage Enhancement (CE) level.

A response message according to an embodiment may be transmitted through a narrowband physical uplink control channel (NPUCCH), a narrowband physical uplink shared channel (NPUSCH), or a narrow physical random access channel (NPRACH).

A message for calling a terminal according to an embodiment may include a paging message.

Receiving downlink data according to an embodiment may include monitoring a search space corresponding to a selected resource and receiving downlink data.

According to various embodiments of the present invention, it is possible to efficiently transmit and receive wireless signals in a wireless communication system.

According to various embodiments of the present invention, downlink data can be efficiently transmitted to a terminal in an RRC_IDLE state.

The effects that can be obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description to aid in understanding of the present invention, provide embodiments for the present invention, and together with the detailed description will be described the technical idea of the present invention.

1 illustrates a structure of a radio frame used in NR.

2 illustrates a slot structure of an NR frame.

3 illustrates the structure of a self-contained slot.

4 illustrates MTC communication.

5 illustrates physical channels used in MTC and general signal transmission using them.

6 illustrates cell coverage improvement in MTC.

7 illustrates a signal band for MTC.

8 illustrates scheduling in legacy LTE and MTC.

9 illustrates physical channels used for NB-IoT and general signal transmission using them.

10 illustrates a frame structure when the subcarrier interval is 15 kHz.

11 illustrates a frame structure when the subcarrier interval is 3.75 kHz.

12 illustrates three operation modes of NB-IoT.

13 illustrates the arrangement of an in-band anchor carrier in an LTE bandwidth of 10 MHz.

14 illustrates transmission of an NB-IoT downlink physical channel/signal in an FDD LTE system.

15 illustrates the NPUSCH format.

16 illustrates an operation when a multi-carrier is configured in FDD NB-IoT.

17 illustrates a flowchart of a method for a base station to transmit early DL data to a terminal in an RRC_IDLE state.

18 illustrates a flow chart of a method for a UE in an RRC_IDLE state to receive early downlink data from a base station.

19 is a flowchart illustrating a process of transmitting and receiving signals between a base station and a terminal according to the embodiment of proposal 1.

20 is a flowchart illustrating a process of receiving downlink data by a terminal in an idle state according to the embodiment of proposal 1.

21 is a flowchart illustrating a process of transmitting downlink data to a terminal in an idle state by a base station according to the embodiment of proposal 1.

22 is a flowchart illustrating a process of transmitting and receiving signals between a base station and a terminal according to the embodiment of proposal 2.

23 is a flowchart illustrating a process of receiving downlink data by a terminal in an idle state according to the embodiment of proposal 2.

24 is a flowchart illustrating a process in which a base station transmits downlink data to a terminal in an idle state according to the embodiment of proposal 2.

25 illustrates an initial network connection and a subsequent communication process.

26 illustrates preamble transmission in NB-IoT RACH.

27 illustrates a DRX cycle for discontinuous reception of a PDCCH.

28 illustrates a DRX cycle for paging.

29 illustrates an extended DRX (eDRX) cycle.

30 illustrates a timing relationship between WUS and PO.

31 illustrates a communication system applied to the present invention.

32 illustrates a wireless device applicable to the present invention.

33 illustrates a signal processing circuit for a transmission signal.

34 shows another example of a wireless device applied to the present invention.

35 illustrates a portable device applied to the present invention.

36 illustrates a vehicle or an autonomous vehicle applied to the present invention.

The following techniques can be used in various wireless access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and the like. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with radio technologies 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 wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is a part of Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) using E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP New Radio or New Radio Access Technology (NR) is an evolved version of 3GPP LTE/LTE-A/LTE-A pro.

In order to clarify the description, the description is based on a 3GPP communication system (eg, LTE, NR), but the technical idea of the present invention is not limited thereto. LTE refers to technology after 3GPP TS 36.xxx Release 8. In detail, LTE technology after 3GPP TS 36.xxx Release 10 is referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 is referred to as LTE-A pro. 3GPP NR refers to the technology after TS 38.xxx Release 15. LTE/NR may be referred to as a 3GPP system. "xxx" means standard document detail number. LTE/NR may be collectively referred to as a 3GPP system. Background art, terms, abbreviations, and the like used in the description of the present invention may refer to matters described in standard documents published before the present invention. For example, you can refer to the following document:

3GPP LTE

-36.211: Physical channels and modulation

-36.212: Multiplexing and channel coding

-36.213: Physical layer procedures

-36.300: Overall description

-36.331: Radio Resource Control (RRC)

3GPP NR

-38.211: Physical channels and modulation

-38.212: Multiplexing and channel coding

-38.213: Physical layer procedures for control

-38.214: Physical layer procedures for data

-38.300: NR and NG-RAN Overall Description

-38.331: Radio Resource Control (RRC) protocol specification

1 illustrates a structure of a radio frame used in NR.

In NR, uplink and downlink transmission is composed of frames. The radio frame has a length of 10ms and is defined as two 5ms half-frames (HF). The half-frame is defined as five 1ms subframes (Subframe, SF). The subframe is divided into one or more slots, and the number of slots in the subframe depends on Subcarrier Spacing (SCS). Each slot includes 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP). When a normal CP is used, each slot includes 14 symbols. When the extended CP is used, each slot includes 12 symbols. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol) and an SC-FDMA symbol (or DFT-s-OFDM symbol).

Table 1 exemplifies that when a normal CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to the SCS.

SCS (15*2^u) N ^slot _symb N ^{frame, u} _slot N ^subframe,u _slot 15KHz (u=0) 14 10 One 30KHz (u=1) 14 20 2 60KHz (u=2) 14 40 4 120KHz (u=3) 14 80 8 240KHz (u=4) 14 160 16

* N ^slot _symb : number of symbols in slot* N ^frame,u _slot : number of slots in frame

* N ^subframe,u _slot : number of slots in ^subframe

Table 2 exemplifies that when an extended CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to the SCS.

SCS (15*2^u) N ^slot _symb N ^frame,u _slot N ^subframe,u _slot 60 kHz 12 40 4

In the NR system, OFDM(A) numerology (eg, SCS, CP length, etc.) may be set differently between a plurality of cells merged into one terminal. Accordingly, the (absolute time) section of the time resource (eg, SF, slot or TTI) (for convenience, collectively referred to as TU (Time Unit)) composed of the same number of symbols may be set differently between the merged cells.

2 illustrates a slot structure of an NR frame.

The slot includes a plurality of symbols in the time domain. For example, in the case of a normal CP, one slot includes 14 symbols, but in the case of an extended CP, one slot includes 12 symbols. The carrier includes a plurality of subcarriers in the frequency domain. RB (Resource Block) is defined as a plurality of (eg, 12) consecutive subcarriers in the frequency domain. Bandwidth Part (BWP) is defined as a plurality of consecutive (P)RBs in the frequency domain, and may correspond to one numerology (eg, SCS, CP length, etc.). The carrier may contain up to N (eg, 5) BWPs. Data communication is performed through the activated BWP, and only one BWP can be activated to one terminal. Each element in the resource grid is referred to as a resource element (RE), and one complex symbol may be mapped.

3 illustrates the structure of a self-contained slot.

In the NR system, a frame is characterized by a self-contained structure in which all of a DL control channel, DL or UL data, and a UL control channel can be included in one slot. For example, the first N symbols in a slot may be used to transmit a DL control channel (hereinafter, a DL control region), and the last M symbols in a slot may be used to transmit a UL control channel (hereinafter, a UL control region). N and M are each an integer of 0 or more. A resource region (hereinafter, a data region) between the DL control region and the UL control region may be used for DL data transmission or UL data transmission. As an example, the following configuration may be considered. Each section was listed in chronological order.

1.DL only configuration

2. UL only configuration

3. Mixed UL-DL configuration

-DL area + GP(Guard Period) + UL control area

-DL control area + GP + UL area

* DL area: (i) DL data area, (ii) DL control area + DL data area

* UL area: (i) UL data area, (ii) UL data area + UL control area

The PDCCH may be transmitted in the DL control region, and the PDSCH may be transmitted in the DL data region. PUCCH may be transmitted in the UL control region, and PUSCH may be transmitted in the UL data region. On the PDCCH, downlink control information (DCI), for example, DL data scheduling information, UL data scheduling information, and the like may be transmitted. In PUCCH, uplink control information (UCI), for example, positive acknowledgment/negative acknowledgment (ACK/NACK) information for DL data, channel state information (CSI) information, scheduling request (SR), and the like may be transmitted. The GP provides a time gap when the base station and the terminal switch from a transmission mode to a reception mode or a process from a reception mode to a transmission mode. Some symbols at a time point at which the DL to UL is switched in the subframe may be set as GP.

Machine Type Communication (MTC)

MTC is a form of data communication in which one or more machines are included, and can be applied to M2M (Machine-to-Machine) or IoT (Internet-of-Things). Here, a machine means an entity that does not require direct human manipulation or intervention. For example, the machine includes a smart meter equipped with a mobile communication module, a vending machine, a portable terminal having an MTC function, and the like.

In 3GPP, MTC has been applied since release 10, and can be implemented to satisfy the criteria of low cost & low complexity, enhanced coverage, and low power consumption. For example, 3GPP Release 12 added features for low-cost MTC devices, and for this, UE category 0 was defined. UE category is an indicator of how much data a terminal can process in a communication modem. UE category 0 UEs can reduce baseband/RF complexity by using a reduced peak data rate, half-duplex operation with relaxed radio frequency (RF) requirements, and a single receive antenna. In 3GPP Release 12, eMTC (enhanced MTC) was introduced, and the price and power consumption of MTC terminals were further lowered by operating only at 1.08 MHz (i.e., 6 RBs), which is the minimum frequency bandwidth supported by legacy LTE.

In the following description, MTC is a term such as eMTC, LTE-M1/M2, bandwidth reduced low complexity/coverage enhanced (BL/CE), non-BL UE (in enhanced coverage), NR MTC, enhanced BL/CE, or equivalent It may be used interchangeably with other terms. In addition, MTC terminals/devices encompass terminals/devices with MTC functions (eg, smart meters, bending machines, portable terminals with MTC functions).

4 illustrates MTC communication.

Referring to FIG. 4, the MTC device 100 is a wireless device that provides MTC communication and may be fixed or mobile. For example, the MTC device 100 includes a smart meter equipped with a mobile communication module, a bending machine, a portable terminal having an MTC function, and the like. The base station 200 is connected to the MTC device 100 using a wireless access technology, and may be connected to the MTC server 700 through a wired network. The MTC server 700 is connected to the MTC devices 100 and provides MTC services to the MTC devices 100. Services provided through MTC are differentiated from existing communication services involving human intervention, and various categories of services such as tracking, metering, payment, medical services, and remote control can be provided through MTC. have. For example, services such as meter reading, water level measurement, use of surveillance cameras, and inventory reporting of vending machines may be provided through MTC. MTC communication has a characteristic that the amount of transmitted data is small, and uplink/downlink data transmission/reception occurs occasionally. Therefore, it is effective to lower the unit cost of the MTC device and reduce battery consumption in accordance with the low data rate. MTC devices generally have little mobility, and accordingly, MTC communication has a characteristic that the channel environment hardly changes.

5 illustrates physical channels used in MTC and general signal transmission using them. In a wireless communication system, an MTC terminal receives information from a base station through a downlink (DL), and the terminal transmits information to the base station through an uplink (UL). The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist according to the type/use of information transmitted and received by them.

When the power is turned off while the power is turned off, the terminal that has newly entered the cell performs an initial cell search operation such as synchronizing with the base station (S1301). To this end, the UE receives a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station, synchronizes with the base station, and obtains information such as a cell identifier (ID). The PSS/SSS used for the initial cell search operation of the terminal may be a PSS/SSS of legacy LTE. Thereafter, the MTC terminal may obtain intra-cell broadcast information by receiving a PBCH (Physical Broadcast Channel) signal from the base station (S1002). Meanwhile, the UE may check the downlink channel state by receiving a DL RS (Downlink Reference Signal) in the initial cell search step.

After completing the initial cell search, the UE may receive more detailed system information by receiving an MPDCCH (MTC PDCCH) and a PDSCH corresponding thereto.

Thereafter, the terminal may perform a random access procedure to complete access to the base station (S1303 to S1306). Specifically, the UE may transmit a preamble through a physical random access channel (PRACH) (S1303), and receive a random access response (RAR) for the preamble through a PDCCH and a PDSCH corresponding thereto (S1004). Thereafter, the UE transmits a PUSCH (Physical Uplink Shared Channel) using scheduling information in the RAR (S1005), and may perform a contention resolution procedure such as a PDCCH and a corresponding PDSCH (S1306).

After performing the above-described procedure, the UE receives MPDCCH signal and/or PDSCH signal (S1107) and physical uplink shared channel (PUSCH) signal and/or physical uplink control channel as a general uplink/downlink signal transmission procedure. The (PUCCH) signal may be transmitted (S1308). Control information transmitted from the UE to the base station is collectively referred to as UCI (Uplink Control Information). UCI includes HARQ ACK/NACK (Hybrid Automatic Repeat and ReQuest Acknowledgement/Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), and the like. CSI includes Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indication (RI), and the like.

6 illustrates cell coverage improvement in MTC.

Various cell coverage extension techniques are being discussed in order to extend the cell coverage (Coverage Extension or Coverage Enhancement, CE) of the base station 1204 for the MTC device 1202. For example, for cell coverage expansion, the base station/terminal may transmit one physical channel/signal over a plurality of opportunities (a bundle of physical channels). In the bundle period, the physical channel/signal may be repeatedly transmitted according to a pre-defined rule. The receiving device may increase the decoding success rate of the physical channel/signal by decoding some or all of the physical channel/signal bundle. Here, the opportunity may mean a resource (eg, time/frequency) through which a physical channel/signal can be transmitted/received. Opportunities for physical channels/signals may include subframes, slots or symbol sets in the time domain. Here, the symbol set may consist of one or more consecutive OFDM-based symbols. The OFDM-based symbol may include an OFDM(A) symbol and a DFT-s-OFDM(A) (= SC-FDM(A)) symbol. Opportunities for a physical channel/signal may include a frequency band, RB set in the frequency domain. For example, PBCH, PRACH, MPDCCH, PDSCH, PUCCH and PUSCH may be repeatedly transmitted.

7 illustrates a signal band for MTC.

Referring to FIG. 7, as a method for lowering the unit cost of the MTC terminal, MTC is a specific band (or channel band) among the system bandwidth of the cell (hereinafter, MTC subband or narrow band), regardless of the system bandwidth of the cell. It can only operate in a narrowband (NB)). For example, the uplink/downlink operation of the MTC terminal may be performed only in the 1.08 MHz frequency band. 1.08 MHz corresponds to six consecutive Physical Resource Blocks (PRBs) in the LTE system, and is defined to follow the same cell search and random access procedures as LTE terminals. FIG. 7(a) illustrates a case where an MTC subband is configured at the center of a cell (eg, 6 PRBs at the center), and FIG. 7(b) illustrates a case where a plurality of MTC subbands are configured within a cell. A plurality of MTC subbands may be configured continuously/discontinuously in the frequency domain. Physical channels/signals for MTC may be transmitted and received in one MTC subband. In the NR system, the MTC subband may be defined in consideration of a frequency range and subcarrier spacing (SCS). For example, in the NR system, the size of the MTC subband may be defined as X consecutive PRBs (ie, 0.18*X*(2^u)MHz bandwidth) (see Table 4 for u). Here, X may be defined as 20 according to the size of a Synchronization Signal/Physical Broadcast Channel (SS/PBCH) block. In the NR system, MTC can operate in at least one Bandwidth Part (BWP). In this case, a plurality of MTC subbands may be configured in the BWP.

8 illustrates scheduling in legacy LTE and MTC.

Referring to FIG. 8, in legacy LTE, a PDSCH is scheduled using a PDCCH. Specifically, the PDCCH may be transmitted in the first N OFDM symbols in a subframe (N=1 to 3), and the PDSCH scheduled by the PDCCH is transmitted in the same subframe. Meanwhile, in MTC, the PDSCH is scheduled using the MPDCCH. Accordingly, the MTC terminal can monitor the MPDCCH candidate in a search space within a subframe. Here, monitoring includes blind decoding of MPDCCH candidates. MPDCCH transmits DCI, and DCI includes uplink or downlink scheduling information. MPDCCH is multiplexed with PDSCH and FDM in a subframe. The MPDCCH is repeatedly transmitted in up to 256 subframes, and the DCI transmitted by the MPDCCH includes information on the number of MPDCCH repetitions. In the case of downlink scheduling, when the repeated transmission of the MPDCCH ends in subframe #N, the PDSCH scheduled by the MPDCCH starts transmission in subframe #N+2. The PDSCH may be repeatedly transmitted in a maximum of 2048 subframes. The MPDCCH and PDSCH may be transmitted in different MTC subbands. Accordingly, the MTC terminal may perform radio frequency (RF) retuning for PDSCH reception after MPDCCH reception. In the case of uplink scheduling, when repeated transmission of the MPDCCH ends in subframe #N, the PUSCH scheduled by the MPDCCH starts transmission in subframe #N+4. When repetitive transmission is applied to a physical channel, frequency hopping between different MTC subbands is supported by RF retuning. For example, when the PDSCH is repeatedly transmitted in 32 subframes, the PDSCH is transmitted in the first MTC subband in the first 16 subframes, and the PDSCH is transmitted in the second MTC subband in the remaining 16 subframes. Can be transmitted. MTC operates in half-duplex mode. HARQ retransmission of MTC is adaptive and asynchronous.

NB-IoT (Narrowband Internet of Things)

NB-IoT represents a narrowband Internet of Things technology that supports low-power wide area networks through existing wireless communication systems (eg, LTE, NR). In addition, NB-IoT may refer to a system for supporting low complexity and low power consumption through a narrowband. Since the NB-IoT system uses OFDM parameters such as subcarrier spacing (SCS) in the same manner as the existing system, there is no need to separately allocate an additional band for the NB-IoT system. For example, one PRB of the existing system band can be allocated for NB-IoT. Since the NB-IoT terminal recognizes a single PRB (single PRB) as each carrier, PRB and carrier may be interpreted as the same meaning in the description of NB-IoT.

Hereinafter, the description of the NB-IoT is mainly described when it is applied to an existing LTE system, but the following description may be extended to a next-generation system (eg, NR system, etc.). In addition, in the present specification, the contents related to NB-IoT can be extended and applied to MTC aiming for similar technical purposes (eg, low-power, low-cost, coverage improvement, etc.). In addition, NB-IoT may be replaced with other equivalent terms such as NB-LTE, NB-IoT enhancement, enhanced NB-IoT, further enhanced NB-IoT, and NB-NR.

9 illustrates physical channels used for NB-IoT and general signal transmission using them.

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

When the power is turned off while the power is turned on again, or a terminal newly entering the cell performs an initial cell search operation such as synchronizing with the base station (S11). To this end, the UE receives a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) from the base station to synchronize with the base station, and obtains information such as a cell identifier (ID). Thereafter, the terminal may obtain intra-cell broadcast information by receiving a narrowband physical broadcast channel (NPBCH) signal from the base station (S12). Meanwhile, the UE may check the downlink channel state by receiving a DL RS (Downlink Reference Signal) in the initial cell search step.

After completing the initial cell search, the UE may receive a narrowband PDCCH (NPDCCH) and a narrowband PDSCH (NPDSCH) corresponding thereto in step S12 to obtain more detailed system information (S12).

Thereafter, the terminal may perform a random access procedure to complete the access to the base station (S13 to S16). Specifically, the terminal may transmit a preamble through a narrowband physical random access channel (NPRACH) (S13), and receive a random access response (RAR) for the preamble through an NPDCCH and a corresponding NPDSCH (S14). Thereafter, the UE may transmit a narrowband physical uplink shared channel (NPUSCH) using scheduling information in the RAR (S15), and perform a contention resolution procedure such as NPDCCH and corresponding NPDSCH (S16). .

After performing the above-described procedure, the terminal may perform reception (S17) and NPUSCH transmission (S18) of an NPDCCH signal and/or an NPDSCH signal as a general uplink/downlink signal transmission procedure. Control information transmitted from the UE to the base station is collectively referred to as UCI (Uplink Control Information). UCI includes HARQ ACK/NACK (Hybrid Automatic Repeat and ReQuest Acknowledgement/Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), and the like. CSI includes Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indication (RI), and the like. In NB-IoT, UCI is transmitted through NPUSCH. According to a request/instruction of a network (eg, a base station), the UE may transmit UCI periodically, aperiodic, or semi-persistent through the NPUSCH.

The NB-IoT frame structure may be set differently according to the subcarrier interval (SCS). FIG. 10 illustrates a frame structure when the subcarrier interval is 15 kHz, and FIG. 11 illustrates a frame structure when the subcarrier interval is 3.75 kHz. The frame structure of FIG. 10 may be used in downlink/uplink, and the frame structure of FIG. 11 may be used only in uplink.

Referring to FIG. 10, the NB-IoT frame structure for a 15 kHz subcarrier interval may be set the same as the frame structure of a legacy system (ie, an LTE system). That is, a 10ms NB-IoT frame may include 10 1ms NB-IoT subframes, and a 1ms NB-IoT subframe may include two 0.5ms NB-IoT slots. Each 0.5ms NB-IoT slot may contain 7 symbols. The 15kHz subcarrier interval can be applied to both downlink and uplink. The symbol includes an OFDMA symbol in downlink and an SC-FDMA symbol in uplink. In the frame structure of FIG. 10, the system band is 1.08 MHz and is defined as 12 subcarriers. The 15kHz subcarrier interval is applied to both downlink and uplink, and since orthogonality with the LTE system is guaranteed, coexistence with the LTE system can be smoothly performed.

Meanwhile, referring to FIG. 11, when the subcarrier interval is 3.75 kHz, a 10ms NB-IoT frame includes 5 2ms NB-IoT subframes, and a 2ms NB-IoT subframe includes 7 symbols and one GP ( Guard Period) symbol may be included. The 2ms NB-IoT subframe may be expressed as an NB-IoT slot or an NB-IoT resource unit (RU). Here, the symbol may include an SC-FDMA symbol. In the frame structure of FIG. 11, the system band is 1.08 MHz and is defined as 48 subcarriers. The 3.75kHz subcarrier spacing is applied only to the uplink, and orthogonality with the LTE system is broken, and performance degradation due to interference may occur.

The drawing illustrates an NB-IoT frame structure based on an LTE system frame structure, and the illustrated NB-IoT frame structure can be extended and applied to a next-generation system (eg, NR system). For example, in the frame structure of FIG. 10, the subframe interval may be replaced with the subframe interval of Table 4.

12 illustrates three operation modes of NB-IoT. Specifically, FIG. 12(a) illustrates an in-band system, FIG. 12(b) illustrates a guard-band system, and FIG. 12(c) illustrates a stand-alone system. Here, the in-band system may be expressed in an in-band mode, the guard-band system may be expressed in a guard-band mode, and the stand-alone system may be expressed in a stand-alone mode. For convenience, the NB-IoT operation mode is described based on the LTE band, but the LTE band may be replaced with a band of another system (eg, an NR system band).

The in-band mode refers to an operation mode for performing NB-IoT in the (legacy) LTE band. In the in-band mode, some resource blocks of the LTE system carrier may be allocated for NB-IoT. For example, in the in-band mode, 1 specific RB (ie, PRB) in the LTE band may be allocated for NB-IoT. In-band mode can be operated in a structure in which NB-IoT coexists in the LTE band. The guard-band mode refers to an operation mode in which NB-IoT is performed in a space reserved for the guard-band of the (legacy) LTE band. Accordingly, in the guard-band mode, a guard-band of an LTE carrier that is not used as a resource block in the LTE system may be allocated for NB-IoT. The (legacy) LTE band may have a guard-band of at least 100 kHz at the end of each LTE band. The stand-alone mode refers to an operation mode in which NB-IoT is performed in a frequency band independently configured from the (legacy) LTE band. For example, in the stand-alone mode, a frequency band (eg, a GSM carrier reallocated in the future) used in a GSM EDGE Radio Access Network (GERAN) may be allocated for NB-IoT.

The NB-IoT terminal searches for an anchor carrier in units of 100 kHz for initial synchronization, and the center frequency of the anchor carrier in the in-band and guard-band must be located within ±7.5 kHz from the 100 kHz channel raster. . In addition, among the LTE PRBs, 6 PRBs are not allocated to NB-IoT. Therefore, the anchor carrier can be located only in a specific PRB.

13 illustrates the arrangement of an in-band anchor carrier in an LTE bandwidth of 10 MHz.

Referring to FIG. 13, a direct current (DC) subcarrier is located in a channel raster. Since the center frequency interval between adjacent PRBs is 180 kHz, the center frequency of PRB indexes 4, 9, 14, 19, 30, 35, 40, and 45 is located at ±2.5kH from the channel raster. Similarly, the center frequency of a PRB suitable as an anchor carrier in the LTE bandwidth of 20 MHz is located at ±2.5 kHz from the channel raster, and the center frequency of the PRB suitable as an anchor carrier in the LTE bandwidths of 3 MHz, 5 MHz, and 15 MHz is at ±7.5 kHz from the channel raster. Located.

In the case of the guard-band mode, the center frequency of the PRB immediately adjacent to the edge PRB of LTE is located at ±2.5 kHz from the channel raster at bandwidths of 10 MHz and 20 MHz. In the case of bandwidths of 3MHz, 5MHz, and 15MHz, the center frequency of the anchor carrier can be located at ±7.5kHz from the channel raster by using a guard frequency band corresponding to three subcarriers from the edge PRB.

Anchor carriers in stand-alone mode are aligned on a 100kHz channel raster, and all GSM carriers including DC carriers can be utilized as NB-IoT anchor carriers.

NB-IoT supports multi-carrier, and a combination of in-band + in-band, in-band + guard-band, guard band + guard-band, stand-alone + stand-alone may be used.

Physical channels such as Narrowband Physical Broadcast Channel (NPBCH), Narrowband Physical Downlink Shared Channel (NPDSCH), and Narrowband Physical Downlink Control Channel (NPDCCH) are provided for NB-IoT downlink, and Narrowband Primary Synchronization Signal (NPSS), Narrowband Physical signals such as Primary Synchronization Signal) and NRS (Narrowband Reference Signal) are provided.

NPBCH delivers MIB-NB (Master Information Block-Narrowband), which is the minimum system information required for system access by the NB-IoT terminal, to the terminal. The NPBCH signal can be repeatedly transmitted 8 times to improve coverage. The TBS (Transport Block Size) of the MIB-NB is 34 bits, and is updated every 640ms TTI period. The MIB-NB includes information such as an operation mode, a system frame number (SFN), a Hyper-SFN, a cell-specific reference signal (CRS) port number, and a channel raster offset.

NPSS is composed of a ZC (Zadoff-Chu) sequence with a sequence length of 11 and a root index of 5. NPSS can be generated according to the following equation.

Here, S(l) for the OFDM symbol index l may be defined as shown in Table 3.

Cyclic prefix length S(3),...,S(13) Normal One One One One -One -One One One One -One One

NSSS is composed of a combination of a ZC sequence with a sequence length of 131 and a binary scrambling sequence such as a Hadamard sequence. The NSSS indicates the PCID to NB-IoT terminals in the cell through a combination of the sequences.

NSSS can be generated according to the following equation.

Here, the variables applied to Equation 2 may be defined as in Equation 3 below.

Here, the binary sequence b _q (m) is defined as shown in Table 4, and b ₀ (m) to b ₃ (m) correspond to columns 1, 32, 64, and 128 of the 128-th Hadamard matrix, respectively. The cyclic shift θ _f for the frame number n _f may be defined as in Equation 4.

q b _q (0),...b _q (127) 0 [1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] One [1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1] 2 [1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1- 1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 -1 1 1- 1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1] 3 [1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1- 1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1 -1 1 1 -1 1 -1 -1 1 1 -1 -1 1 -1 1 1 -1]

Here, nf represents a radio frame number. mod represents the modulo function.

The downlink physical channel/signal includes NPSS, NSSS, NPBCH, NRS, NPDCCH and NPDSCH.

14 illustrates transmission of an NB-IoT downlink physical channel/signal in an FDD LTE system. The downlink physical channel/signal is transmitted through one PRB and supports 15kHz subcarrier interval/multi-tone transmission.

Referring to FIG. 14, NPSS is transmitted in the 6th subframe of every frame, and NSSS is transmitted in the last (eg, 10th) subframe of every even frame. The terminal may acquire frequency, symbol, and frame synchronization using synchronization signals (NPSS, NSSS) and search for 504 PCIDs (Physical Cell IDs) (ie, base station IDs). NPBCH is transmitted in the first subframe of every frame and carries NB-MIB. NRS is provided as a reference signal for downlink physical channel demodulation and is generated in the same manner as LTE. However, NB-PCID (Physical Cell ID) (or NCell ID, NB-IoT base station ID) is used as an initialization value for generating the NRS sequence. NRS is transmitted through one or two antenna ports. NPDCCH and NPDSCH may be transmitted in the remaining subframes excluding NPSS/NSSS/NPBCH. NPDCCH and NPDSCH cannot be transmitted together in the same subframe. NPDCCH carries DCI, and DCI supports three types of DCI formats. DCI format N0 includes NPUSCH (Narrowband Physical Uplink Shared Channel) scheduling information, and DCI formats N1 and N2 include NPDSCH scheduling information. The NPDCCH can be transmitted up to 2048 times to improve coverage. NPDSCH is used to transmit data (eg, TB) of a transport channel such as a DL-SCH (Downlink-Shared Channel) and a PCH (Paging Channel). The maximum TBS is 680 bits, and a maximum of 2048 repetitions can be transmitted to improve coverage.

The uplink physical channel includes a Narrowband Physical Random Access Channel (NPRACH) and NPUSCH, and supports single-tone transmission and multi-tone transmission. Single-tone transmission is supported for subcarrier spacing of 3.5kHz and 15kHz, and multi-tone transmission is supported only for subcarrier spacing of 15kHz.

15 illustrates the NPUSCH format.

NPUSCH supports two formats. NPUSCH format 1 is used for UL-SCH transmission, and the maximum TBS is 1000 bits. NPUSCH format 2 is used for transmission of uplink control information such as HARQ ACK signaling. NPUSCH format 1 supports single-/multi-tone transmission, and NPUSCH format 2 supports only single-tone transmission. For single-tone transmission, pi/2-BPSK (Binary Phase Shift Keying) and pi/4-QPSK (Quadrature Phase Shift Keying) are used to reduce the Peat-to-Average Power Ratio (PAPR). In the NPUSCH, the number of slots occupied by one resource unit (RU) may differ according to resource allocation. The RU represents the smallest resource unit to which TB is mapped, and is composed of N ^UL _symb * N ^UL _slots consecutive SC-FDMA symbols in the time domain and N ^RU _sc consecutive subcarriers in the frequency domain. Here, N ^UL _symb indicates the number of SC-FDMA symbols in the slot, N ^UL _slots indicates the number of slots, and N ^RU _sc indicates the number of subcarriers constituting the RU.

Table 5 illustrates the configuration of an RU according to the NPUSCH format and subcarrier spacing. In the case of TDD, the supported NPUSCH format and SCS vary according to the uplink-downlink configuration.

NPUSCH format Subcarrier spacing Supported uplink-downlink configurations N ^RU _SC N ^UL _slots N ^UL _symb One 3.75 kHz 1, 4 One 16 7 15 kHz 1 2 3 4 5 One 16 3 8 6 4 12 2 2 3.75 kHz 1, 4 One 4 15 kHz 1 2 3 4 5 One 4

Scheduling information for UL-SCH data (eg, UL-SCH TB) transmission is included in DCI format NO, and DCI format NO is transmitted through NPDCCH. The DCI format NO includes information on the start time of the NPUSCH, the number of repetitions, the number of RUs used for TB transmission, the number of subcarriers, and the resource location in the frequency domain, MCS, and the like.

Referring to FIG. 15, DMRS is transmitted in one or three SC-FDMA symbols per slot according to the NPUSCH format. DMRS is multiplexed with data (eg, TB, UCI), and is transmitted only in the RU including data transmission.

16 illustrates an operation when a multi-carrier is configured in FDD NB-IoT.

In FDD NB-IoT, a DL/UL anchor-carrier is basically configured, and a DL (and UL) non-anchor carrier may be additionally configured. Information on the non-anchor carrier may be included in RRCConnectionReconfiguration. When a DL non-anchor carrier is configured (DL add carrier), the terminal receives data only from the DL non-anchor carrier. On the other hand, synchronization signals (NPSS, NSSS), broadcast signals (MIB (Master Information Block), SIB (System Information Block)), and paging signals are provided only in the anchor-carrier. When the DL non-anchor carrier is configured, the UE listens only to the DL non-anchor carrier while in the RRC_CONNECTED state. Similarly, when a UL non-anchor carrier is configured (UL add carrier), the UE transmits data only on the UL non-anchor carrier, and simultaneous transmission in the UL non-anchor carrier and the UL anchor-carrier is not allowed. When transitioning to the RRC_IDLE state, the terminal returns to the anchor-carrier.

16 shows a case where only an anchor-carrier is configured for UE1, a DL/UL non-anchor carrier is additionally configured for UE2, and a DL non-anchor carrier is additionally configured for UE3. Accordingly, carriers on which data is transmitted/received in each UE are as follows.

-UE1: data reception (DL anchor-carrier), data transmission (UL anchor-carrier)

-UE2: data reception (DL non-anchor-carrier), data transmission (UL non-anchor-carrier)

-UE3: data reception (DL non-anchor-carrier), data transmission (UL anchor-carrier)

The NB-IoT terminal cannot transmit and receive at the same time, and transmit/receive operations are limited to one band each. Therefore, even if a multi-carrier is configured, the terminal only requires one transmission/reception chain of the 180 kHz band.

Embodiment: downlink data transmission for a terminal in an idle state

According to the conventional method, when a base station wants to transmit short data to a terminal in RRC_IDLE mode or RRC_INACTIVE mode without establishing an RRC connection with a specific cell, the terminal transmits a paging message to the corresponding terminal, and the terminal receiving the paging message It is necessary to establish an RRC connection with an appropriate cell by performing a random access process. In addition, after transmitting data to the terminal, the base station must perform a procedure of releasing the RRC connection with the terminal to return the terminal to the RRC_IDLE/RRC_INACTIVE mode. However, when the size of downlink data to be transmitted by the base station to the terminal is small, and transmission of short downlink data occurs very occasionally, network overhead due to the RRC connection/release procedure and battery consumption of the terminal are inefficiently increased. Therefore, for short data transmission that occurs infrequently, there is a need for a method of transmitting downlink data to a terminal in the RRC_IDLE mode without an RRC connection/release procedure.

In the present invention, without a procedure for changing the RRC state (e.g., entering the RRC_CONNECTED mode from the RRC_IDLE mode), a terminal in the RRC_IDLE mode proposes a method for efficiently receiving data from the viewpoint of power consumption and transmission delay from the base station. .

For convenience of explanation, the proposed method is mainly described based on the NB-IoT system, but may be applied to a system characterized by low power/cost such as eMTC, and furthermore, to a general communication system. It may be applied, and specific channels and parameters may be defined differently according to characteristics of each system.

Depending on the embodiment, the RRC_IDLE mode may be expressed as an RRC_IDLE state, an IDLE state, or an IDLE mode, and the RRC_INACTIVE mode may be expressed as an RRC_INACTIVE state, INACTIVE state, or INACTIVE mode.

In a general communication system, before transmitting/receiving data, the RRC state of the terminal needs to be transitioned to RRC_CONNECTED. The procedure for changing the RRC state of the terminal is performed through a random access process, (1) the random access process is performed while the terminal enters the cell, or (2) the base station needs to transmit downlink data to a specific terminal. When present, it can be performed at the request of the base station. In addition, the process of (1) can be used to change the UE in the RRC_IDLE state to the RRC_CONNECTED state, and the process of (2) is (2-1) the base station directly instructs the UE in the RRC_CONNECTED state through the PDCCH, or (2-2) The base station may transmit a paging message to the terminal in the RRC_IDLE state to instruct to enter the random access process.

The "early DL data transmission" proposed by the present invention is based on a situation in which the base station transmits data to the terminal in the RRC_IDLE state in the process (2-2). However, as a variant of (2-2), the base station calls the terminal in the RRC_IDLE state through a new channel for a specific purpose (for example, a channel periodically monitored by the terminal in the RRC_IDLE state), not a paging message. It may be applied to the method.

First, based on the NB-IoT system, the random access process can be briefly summarized as follows.

The random access process starts with transmission of an NPRACH called Msg.1 (from the terminal), and when the base station detects Msg.1, it transmits Msg.2 corresponding to Msg.1 in downlink. Msg.2 is composed of NPDCCH and NPDSCH, and the NPDCCH is transmitted by scrambling with RA_RNTI (Random Access RNTI, used for PRACH Response, Radio Network Temporary Identifier). RA_RNTI is composed of an uplink (time/frequency) resource transmitting Msg.1, and all UEs transmitting Msg.1 in the same uplink resource can detect the corresponding NPDCCH. The NPDCCH is a DL grant (DL_grant) for scheduling the NPDSCH, and is transmitted in the form of DCI format N1 in a common search space type-2. The corresponding NPDSCH includes and transmits a UL grant (UL_grant) composed of a Medium Access Control (MAC) message, and the UL grant is generally referred to as a random access response (RAR). The base station divides one or more specific sequences (starting frequency index) detected in Msg.1 that can be included in the uplink resource indicated by RA_RNTI into RAPID (Random Access Preamble ID) And, the UL grant for each RAPID is delivered to the MAC layer. At this time, the UL grant delivered to the MAC layer is generally different from the UL grant (DCI format N0) included in the NPDCCH, and is characteristically used only for Msg.3 scheduling.

In general, the random access process is divided into contention-free and contention-based, and the random access process that the terminal initially uses for cell entry is contention-based random access (CBRA). Access) process. For example, a terminal transmitting Msg.3 may be a plurality of terminals transmitting Msg.1 using the same RAPID, and in order to distinguish Msg.3 transmitted from different terminals in the process of Msg.4 (i.e. , To resolve the collision), each terminal transmits a contention resolution ID (ID) included in Msg.3, the collision resolution ID may mean a unique ID of each terminal. In addition, Msg.3 is scrambled and transmitted by TC-RNTI (temporary cell-RNT), and is transmitted from the base station to the terminal through Msg.2. At this time, TC-RNTI means an RNTI used to transmit to a specific terminal after RACH.

The base station checks the collision resolution ID in the received Msg.3, and transmits Msg.4 to the terminals corresponding to the confirmed collision resolution ID. In this case, Msg.4 may include the collision resolution ID received from Msg.3. The UE detects Msg.4 using the TC-RNTI, and if Msg.4 contains the collision resolution ID transmitted through Msg.3, the TC-RNTI is used as the C-RNTI. The contention resolution of the terminal for which the above process is completed is resolved, and the RRC state of the terminal naturally transitions to the RRC_CONNECTED state.

In NB-IoT, each UE may select a Coverage Enhancement (CE) level based on RSRP received through a downlink NRS or NSSS. And, before transmitting the NPRACH at the selected CE level, the UE may inform whether it is a UE capable of multi-tone uplink transmission by means of an NPRACH starting carrier index. For example, the terminal may transmit Msg.1 to inform the base station of its CE level and multi-tone capability, and the base station may provide an appropriate Msg.3 based on the CE level and multi-tone capability of the terminal. Can be scheduled. If the NPRACH start carrier region for notifying the multi-tone capability to the resource for the CE level of the terminal is not separately allocated by the base station (SIB2-NB or SIB22-NB), the terminal is a single-tone capability region Selects the NPRACH start carrier. In addition, even if there is an NPRACH start carrier area for notifying the multi-tone capability in the resource for the CE level of the UE, if the UE does not receive Msg.2 within a certain time after transmitting Msg.1, the CE level is obtained. Increase by 1. In addition, even when the NPRACH start carrier region for informing the multi-tone capability is not separately allocated to the resource for the newly selected CE level, the UE selects the NPRACH start carrier in the single-tone capability region.

As described above, the UE in the RRC_IDLE state can determine its own CE level based on the reference value for determining the CE level set by the base station and the NRSRP measured by itself, and Msg.1 according to the determined CE level. The resource to be transmitted may be selected differently. That is, because the base station cannot manage the CE level of the terminal in the RRC_IDLE state, the terminal determines the CE level of the terminal through the random access resource used for transmission of Msg.1 in the random access procedure for accessing the cell. Indirectly notifies the base station.

When the base station has data to be transmitted to the terminal in the RRC_IDLE state, the base station requests a random access attempt through a paging message expected to be monitored by the terminal, and the terminal receiving the paging message performs the CBRA process in order to perform the CBRA process. Transmit 1. That is, after the terminal enters the RRC_CONNECTED state by performing the above-described transmission/reception process of Msg. 1 to 4, the base station may transmit data to the terminal. However, the above-described processes require a long procedure for the terminal to perform a contention resolution (CR) process, and after the base station transmits data to the terminal, RRC release in order to return the terminal to the RRC_IDLE state again. There is a drawback of having to perform all (release) procedures. The above-described disadvantage may be a fatal disadvantage to an eMTC/NB-IoT terminal characterized by low power consumption, and may be more inefficient when the size of data to be transmitted by the base station to the terminal is not large. Accordingly, as a method that can omit the above-described procedure, the following procedure may be considered.

(1) Request a CFRA process to a UE in RRC_IDLE state through a specific message

(2) The base station detects a preamble from the Msg.1 resource instructed to use the terminal for use in the CFRA process, and transmits data to the terminal through a response message for the detected preamble.

The specific message is a paging channel, or MT-EDT (Mobile Termination-Early Data Transmission; a series of procedures used to transmit data to a terminal in an RRC_IDLE state without transition of an RRC state) for a terminal in an RRC_IDLE state It can be delivered through new channels that need to be monitored periodically.

A method for the UE to transmit a signal in response to a specific message received from the base station may be a specific NPUSCH format 1 (PUSCH) and/or NPUSCH format 2 (PUCCH) resource as well as CBRA. In addition, the terminal may transmit an ACK/NACK message for received data to the base station after the process of (2).

17 illustrates a flowchart of a method for a base station to transmit early DL data to a terminal in an RRC_IDLE state.

In step S1700, the base station may transmit a message for calling the terminal to the terminal. For convenience of description, a message for calling the terminal may be referred to as a call message. Step S1700 may correspond to step (1). Accordingly, the call message may be transmitted through a paging channel or through a channel for MT-EDT. In addition, in step S1700, the call message may include resource information as proposed in the present invention. A detailed description of resource information included in the call message will be described later.

In step S1710, the base station may receive an uplink signal from the terminal in response to the call message. In addition, in step S1720, the base station may transmit early DL data to the terminal through a response message for the received uplink signal. Steps S1710 and S1720 may correspond to step (2). Accordingly, in step S1710, the uplink signal may be received through NPRACH, or may be received through NPUSCH format 1 or NPUSCH format 2, and resources for the uplink signal may be configured according to the proposed method described later in section 2. . In step S1720, the early downlink data may be transmitted to the terminal through the NPDSCH (scheduled by NPDCCH).

18 illustrates a flow chart of a method for a UE in an RRC_IDLE state to receive early downlink data from a base station.

In step S1800, the terminal may receive a message (for convenience, referred to as a call message) for calling the terminal from the base station. Step S1800 may correspond to step (1). Thus, the call message may be received through a paging channel or through a channel for MT-EDT. In addition, the call message in step S1800 may include resource information as proposed in the present invention. A detailed description of resource information included in the call message will be described later in Section 2.

In step S1810, the terminal may transmit an uplink signal to the base station in response to the call message. In addition, in step S1820, the terminal may receive early downlink data from the base station through a response message for the transmitted uplink signal. Steps S1810 and S1820 may correspond to step (2). Accordingly, in step S1810, the uplink signal may be transmitted through NPRACH or through NPUSCH format 1 or NPUSCH format 2, and resources for the uplink signal may be configured according to a method described later in section 2. In step S1820, the early downlink data may be received from the base station through the NPDSCH (scheduled by NPDCCH).

2. Method for requesting uplink signal/channel transmission from RRC_IDLE UE and UE's procedure for this

Hereinafter, for MT-EDT, a method for a base station to call a terminal in an RRC_IDLE state and a response procedure for a terminal to a call from the base station are proposed. The proposed method is not applied only in the MT-EDT situation, and may be applied to a general situation for calling a UE in the RRC_IDLE state without a collision resolution procedure.

The network cannot know exactly in the range of which base station (cell) the terminal in the RRC_IDLE/RRC_INACTIVE state exists. Accordingly, in order to transmit a paging message to a terminal in the RRC_IDLE/RRC_INACTIVE state, the paging message is transmitted through all cells in a tracking area in which the corresponding terminal may exist. Therefore, in order to transmit the downlink data to the terminal starting from the transmission of the paging message, the network can know from which cell the terminal received the paging message, and the downlink data is transmitted through the cell in which the terminal received the paging message. In order to be transmitted, a process of feedback from the terminal is required. That is, when the paging message is transmitted to the terminal through a plurality of cells and the terminal receiving the paging message transmits the response message, the downlink data transmission can be continued in the cell receiving the response message from the terminal. In addition, even if it is known that the network is a terminal with relatively static characteristics by internal/external methods, and it is possible to know which cell coverage area the terminal is in, a change in the channel environment between the terminal and the base station or the terminal Due to the limited mobility of, the channel state between the base station and the terminal may change. For example, when an obstacle occurs or disappears between the terminal and the base station, a channel state between the terminal and the base station may change or the channel may be disconnected. Therefore, even if it is possible to know which cell the UE is in the coverage area, a feedback process of the UE is required for stable downlink data transmission. For convenience of explanation, the eNB transmits to call the UE in the RRC_IDLE state. The channel to be called is called a call, and a message transmitted through the CALL is called a call message. For example, the call message may include a paging message. The call message may include terminal ID information (eg, (T-)IMSI) for calling a specific terminal, and information on resources used by the terminal to transmit a response message. Hereinafter, for convenience of description, an uplink resource to be used by the UE to transmit a response message is referred to as a feedback resource (FBR), and a message indicating the feedback resource is referred to as a feedback message (FBM).

Depending on the embodiment, the feedback resource may include a PUCCH resource, a PUSCH resource, or a random access resource. For example, the random access resource may include a resource for transmitting a preamble in a random access procedure. If the network does not know which cell coverage area the UE in the RRC_IDLE state belongs to, since the uplink feedback resource of a specific cell cannot be dedicated to the UE, the random access resource will be used as the feedback resource. I can. In addition, even if the network can assume the cell to which the terminal in the RRC_IDLE state belongs, the propagation delay between the terminal and the base station is not static due to the mobility of the terminal or a change in the channel (path) environment between the base station and the terminal. In this case, it is difficult to accurately synchronize the feedback timing of the terminal and the base station timing. Therefore, even if UL timing sync is not exactly correct, a resource for transmitting a random access preamble may be used as a feedback resource so that the base station can easily detect the feedback of the terminal.

On the other hand, when the network knows or can assume the cell to which the UE in the RRC_IDLE state belongs, and the cell radius is very small or the UE is very static, it can be assumed that uplink timing synchronization is maintained, PUCCH or PUSCH resource This can be used as a feedback resource.

In addition, according to embodiments, the feedback resource may be determined differently according to information included in the response message of the terminal. For example, if the size of the information included in the response message is relatively small (for example, only whether the response message is within the coverage area of the cell managed by the base station is indicated by on/off) If so), PUCCH resources may be used as feedback resources. On the other hand, when the size of information included in the response message is relatively large (for example, when information necessary for the base station to schedule, such as information on RSRP of the terminal, is included in the response message), PUSCH resources are used as feedback resources. It may be utilized, but is not limited thereto.

[Proposal 1] Two or more feedback resources to be used by UEs in RRC_IDLE state How to set

19 is a flowchart illustrating a process of transmitting and receiving signals between a base station and a terminal according to the embodiment of proposal 1.

Referring to FIG. 19, since the base station cannot know the CE level of the terminal in the RRC_IDLE state, two or more feedback resources may be set (S1900). Each feedback resource may include resources suitable for uplink transmission for each CE level of the UE, and the UE may select one of two or more feedback resources based on its CE level to transmit a response message. have. In this case, the resource suitable for uplink transmission may mean a resource suitable for the base station to detect the response message of the terminal with high reliability. According to an embodiment, if the NPRACH resource is set as a feedback resource, the feedback resource may include Msg.1 resources for each CE level, and Msg.1 is a contention-free random access (CFRA) procedure. Can be included.

The base station may transmit a call message including information on a plurality of feedback resources to the terminal (S1910). The call message may mean a message for calling the terminal in the RRC_IDLE state. For example, the call message may be a paging message, but is not limited thereto. Depending on the embodiment, the call message may include a feedback message, and information on a plurality of feedback resources may be included in the feedback message and transmitted, but is not limited thereto. The call message may include an independent feedback message for each feedback resource. In addition, according to embodiments, one feedback message may indicate a plurality of feedback resources, and one feedback message indicating a plurality of feedback resources may be interpreted as a plurality of feedback resources by the terminal.

The terminal may know information on a plurality of feedback resources through the received call message, and may select one feedback resource from among the plurality of feedback resources based on its CE level (S1920). Then, the terminal may transmit a response message using the selected feedback resource (S1930). For example, the feedback message indicates a contention-free specific RAPID, and the terminal may recognize that the same RAPID is allocated to itself in the random access resource for each CE level. If the CE level of the terminal is 1, the terminal may transmit Msg.1 based on the random access resource for CE level 1 and the corresponding RAPID.

The base station cannot know which of the plurality of feedback resources the terminal will use to transmit the response message. Accordingly, the base station may receive and detect all channels corresponding to a plurality of feedback resources in order to receive a response message from the terminal. After receiving the response message from the terminal, the base station may transmit downlink data to the terminal (S1940).

In addition, according to an embodiment, when a resource such as NPUSCH format 1 (PUSCH) or NPUSCH format 2 (PUCCH) is set as a feedback resource, NPUSCH format 1 (PUSCH) or NPUSCH format 2 (PUCCH) that can be used as a feedback resource A specific combination of the resources of may be preset through an upper message (eg, RRC message), and the terminal selects a resource to transmit a response message based on a combination of a feedback message and a higher message included in the call message. I can.

The base station may periodically broadcast information on a resource pool that can be used as a feedback resource to all terminals in a cell. For example, the base station may broadcast information on a resource pool that can be used as a feedback resource through a System Information Block (SIB). And, when there is downlink data to be transmitted to UE A in the RRC_IDLE state, two or more resources are selected from the resource pool and set as a feedback resource for UE A, including information on the feedback resource for UE A. A feedback message can be transmitted to terminal A. Accordingly, the terminal A may select a resource for transmitting the response message by combining the information on the broadcasted resource pool and the feedback message.

Or, according to an embodiment, without transmitting a separate feedback message, the terminal acquires information on the feedback resource through a message broadcast from the base station, and transmits a response message based on the information on the feedback resource. You can also choose a feedback resource.

The base station may receive and detect all two or more feedback resources set by itself (or allocated to the terminal) and transmit a response to the response message of the terminal to the terminal. In addition, the terminal may receive and detect only a channel corresponding to the selected feedback resource (for example, a search space for detecting Msg.2 corresponding to Msg.1 for each CE level) and expect a response from the base station.

Hereinafter, various embodiments of the proposal 1 will be described in more detail with reference to FIGS. 20 to 21.

20 is a flowchart illustrating a process in which a terminal receives downlink data according to the embodiment of proposal 1.

Referring to FIG. 20, the terminal may receive a call message for calling the terminal in the idle state from the base station (S2000). Depending on the embodiment, the idle state may be referred to as the aforementioned RRC_IDLE state or RRC_IDLE mode. The call message may be a paging message, and may be transmitted through a paging channel or a new channel that the UE in the RRC_IDLE state should periodically monitor, but is not limited thereto. The call message may include information on a plurality of resources set for the terminal to transmit a response message. The resource set for the UE to transmit the response message may refer to the above-described feedback resource. Depending on the embodiment, information on the feedback resource may be included in the feedback message, and the feedback message may be included in the call message and transmitted. The plurality of resources may include resources suitable for uplink transmission for each CE level of the terminal, and according to embodiments, a random access resource, an NPUCCH resource, or an NPUSCH resource may be used as a feedback resource. In this case, the random access resource may mean a resource for transmitting a preamble in a random access process.

The terminal may transmit a response message for receiving downlink data to the base station in response to the call message (S2010). Specifically, the terminal may select one of a plurality of resources indicated through the call message, and transmit a response message using the selected resource. In this case, the terminal may select a resource based on information on channel quality between the terminal and the base station. The information on the channel quality between the terminal and the base station may include information on the CE level of the terminal, but is not limited thereto.

The terminal may receive downlink data from the base station (S2020). For example, the UE may receive and detect a channel corresponding to a resource used for transmission of a response message and receive downlink data. For example, when a random access resource (eg, NPRACH resource) is used as a feedback resource, the plurality of feedback resources may be resources for Msg.1 for each CE level of the UE. The UE corresponding to CE level 1 can transmit a response message by selecting a resource for transmitting Msg.1 in CE level 1 from among a plurality of feedback resources, and Msg.2 corresponding to Msg.1 in CE level 1 It is possible to receive and detect the search space for detecting the downlink data.

21 is a flowchart illustrating a process of transmitting downlink data to a terminal in an idle state by a base station according to the embodiment of proposal 1.

Referring to FIG. 21, the base station may transmit a call message for calling the terminal in an idle state to the terminal (S2100). The call message may include information on a plurality of feedback resources for the terminal to transmit a response message to the base station. Specifically, information on the feedback resource may be included in the feedback message, and the feedback message may be included in the call message and transmitted, but is not limited thereto. The plurality of resources may include resources suitable for uplink transmission for each CE level of the terminal, and according to embodiments, a random access resource, an NPUCCH resource, or an NPUSCH resource may be used as a feedback resource.

The base station may receive a response message from the terminal (S2110). The response message may be transmitted based on a resource selected by the terminal among a plurality of resources. Since the base station does not know which resource from among the plurality of resources set as the feedback resource to transmit the response message, the base station receives and detects all channels corresponding to the plurality of resources set as the feedback resource, and is selected by the UE. A response message may be received through a channel corresponding to the resource.

In response to the response message received from the terminal, the base station may transmit downlink data to the terminal (S2120).

[Suggestion 2] A method of configuring one feedback resource based on information of a terminal in an RRC_IDLE state

22 is a flowchart illustrating a process of transmitting and receiving signals between a base station and a terminal according to the embodiment of proposal 2.

Referring to Figure 22, the base station can know the information of the terminal (e.g., subscription-based UE differentiation (subscription-based UE differentiation) or the subscription/service information of the terminal), and determine that there is no mobility of the terminal from the information of the terminal. If possible, the base station may set only one feedback resource in the call message (S2200). In addition, the base station may transmit a call message including information on one feedback resource to the terminal (S2210).

The terminal may receive a call message from the base station and transmit a response message based on information on a feedback resource included in the call message (S2220). The terminal may transmit a response message using one feedback resource set by the base station.

Depending on the embodiment, the terminal interprets the feedback resource set by the base station, based on the information on the feedback resource included in the received call message, and determines whether or not the response message can be transmitted using the analyzed feedback resource. You can perform more operations. For example, before the terminal enters the RRC_IDLE state, the terminal may analyze the feedback resource based on radio environment information (eg, CE level) that the base station and the terminal finally know each other. For example, if the UE is at CE level 2 before entering the RRC_IDLE state, the UE may analyze the feedback resource based on CE level 2. That is, when the feedback message indicates a specific RAPID, the UE may interpret the resource related to the RAPID in the CFRA resource for CE level 2 as a feedback resource.

However, the base station may request a verification procedure for determining whether the terminal can transmit a response to the call message using the corresponding feedback resource. Accordingly, the terminal may determine whether to transmit a response message using the feedback resource based on the information on the mobility of the terminal. For example, in order to indirectly test that there was no mobility of the terminal, the base station may allow the terminal to use the feedback resource interpreted as above only when a specific condition is satisfied based on (N)RSRP. . For example, when the amount of change in the (N)RSRP value is less than or equal to the threshold value, the terminal may transmit a response message to the base station using a feedback resource. Specifically, when the amount of change in (N)RSRP is greater than the threshold value, the base station uses the CBRA resource by the terminal to Msg. Can be set to transmit 1. (N) If the amount of change in the RSRP value is less than or equal to the threshold value, the base station uses the feedback resource set by the terminal to Msg. 1 can be sent. For example, the amount of change in (N)RSRP is the difference between the (N)RSRP value measured at a specific time point and the (N)RSRP value measured at the time the call message is received, or the (N)RSRP value measured at a specific time point. It may be defined as a difference value of the measured (N)RSRP value between a time point at which a call message is received and a time point at which the terminal transmits a response message using a feedback resource, but is not limited thereto.

Upon receiving the response message from the terminal, the base station may transmit downlink data to the terminal (S2230).

Depending on the embodiment, if the feedback resource is a resource such as NPUSCH format 1 (PUSCH) or NPUSCH format 2 (PUCCH), for a resource of NPUSCH format 1 (PUSCH) or NPUSCH format 2 (PUCCH) that can be used as a feedback resource A specific combination may be preset through an upper message (eg, an RRC message), and the terminal may analyze a feedback resource by combining a feedback message included in a call message and a higher message.

Hereinafter, various embodiments of the proposal 2 will be described in more detail with reference to FIGS. 23 to 24.

23 is a flowchart illustrating a process in which a terminal in an idle state receives downlink data according to the embodiment of proposal 2.

Referring to FIG. 23, the terminal may receive a call message for calling the terminal in an idle state from the base station (S2300). The call message may include information on one resource set to be used by the terminal to transmit a response message. As described above, a resource set to be used by the terminal to transmit a response message may be referred to as a feedback resource, and the idle state may be referred to as the aforementioned RRC_IDLE state or RRC_IDLE mode.

The terminal may transmit a response message based on one resource set by the base station (S2310).

Depending on the embodiment, the terminal may additionally perform an operation of analyzing information on the feedback resource included in the call message based on channel environment information before the terminal enters the idle state. For example, before the terminal enters the idle state, the base station and the terminal may analyze information on the feedback resource based on radio environment information (or channel environment information) that the base station and the terminal finally know each other. Depending on the embodiment, the channel environment information may be CE level information of the terminal, but is not limited thereto. In this case, the terminal may transmit a response message using the feedback resource only when a preset condition is satisfied. For example, when the mobility of the terminal is less than or equal to a threshold level, the terminal may transmit a response message using the feedback resource. The mobility of the terminal may be determined based on the (N) RSRP value, but is not limited thereto. For example, only when the amount of change in the (N)RSRP value is less than or equal to a threshold, the terminal may be configured to transmit a response message using a feedback resource. In this case, when the amount of change in the (N)RSRP value is greater than the threshold value, the terminal may be configured to transmit a response message using CBRA resources.

After transmitting the response message to the base station, the terminal may receive downlink data from the base station (S2320).

24 is a flowchart illustrating a process of transmitting downlink data to a terminal in an idle state by a base station according to the embodiment of proposal 2.

Referring to FIG. 24, the base station may transmit a call message for calling the terminal in an idle state to the terminal (S2400). In this case, the call message may include information on one feedback resource set to be used by the terminal to transmit a response message. If the base station can know the information of the terminal in advance and can determine that the mobility of the terminal is less than the threshold level from the information of the terminal, the base station can set only one feedback resource.

The base station may receive a response message transmitted based on one set resource from the terminal (S2410). Depending on the embodiment, it may be necessary to additionally verify whether the terminal can transmit the response message using the configured feedback resource. Accordingly, the base station may allow the terminal to transmit a response message using the feedback resource only when a preset condition is satisfied. For example, the base station may allow the terminal to determine whether to use the feedback resource based on the mobility information of the terminal. Specifically, the base station may set the terminal to transmit a response message using the feedback resource only when the mobility of the terminal is below a threshold level. For example, the base station configures the terminal to use the feedback resource only when the amount of change in the (N) RSRP value is less than the threshold value, and the terminal to use the CBRA resource when the amount of change in the (NRSR) value is greater than the threshold value. However, it is not limited thereto. When additional verification is performed on whether or not the response message can be transmitted using the feedback resource, the base station may receive the transmitted response message based on the information on the mobility of the terminal.

After receiving the response message from the terminal, the base station may transmit downlink data to the terminal (S2420).

Network access and communication process

The terminal may perform a network access procedure to perform the procedures and/or methods described/suggested above. For example, while accessing a network (eg, a base station), the terminal may receive system information and configuration information necessary to perform the procedures and/or methods described/suggested above and store them in a memory. Configuration information required for the present invention may be received through higher layer (eg, RRC layer; Medium Access Control, MAC, layer, etc.) signaling.

25 illustrates an initial network connection and a subsequent communication process. In NR, a physical channel and a reference signal may be transmitted using beam-forming. When beam-forming-based signal transmission is supported, a beam-management process may be involved in order to align beams between the base station and the terminal. In addition, the signal proposed in the present invention can be transmitted/received using beam-forming. In the Radio Resource Control (RRC) IDLE mode, beam alignment may be performed based on SSB. On the other hand, in the RRC CONNECTED mode, beam alignment may be performed based on CSI-RS (in DL) and SRS (in UL). Meanwhile, when beam-forming-based signal transmission is not supported, an operation related to a beam may be omitted in the following description.

Referring to FIG. 25, a base station (eg, BS) may periodically transmit an SSB (S702). Here, SSB includes PSS/SSS/PBCH. SSB may be transmitted using beam sweeping (see FIG. 14). The PBCH includes a Master Information Block (MIB), and the MIB may include scheduling information about Remaining Minimum System Information (RMSI). Thereafter, the base station may transmit RMSI and other system information (OSI) (S704). The RMSI may include information (eg, PRACH configuration information) necessary for the terminal to initially access the base station. Meanwhile, after performing SSB detection, the UE identifies the best SSB. Thereafter, the terminal may transmit a RACH preamble (Message 1, Msg1) to the base station using the PRACH resource linked/corresponding to the index (ie, the beam) of the best SSB (S706). The beam direction of the RACH preamble is associated with the PRACH resource. The association between the PRACH resource (and/or the RACH preamble) and the SSB (index) may be set through system information (eg, RMSI). Thereafter, as part of the RACH process, the base station transmits a RAR (Random Access Response) (Msg2) in response to the RACH preamble (S708), and the UE uses the UL grant in the RAR to make Msg3 (e.g., RRC Connection Request). After transmitting (S710), the base station may transmit a contention resolution message (Msg4) (S720). Msg4 may include RRC Connection Setup.

When an RRC connection is established between the base station and the terminal through the RACH process, subsequent beam alignment may be performed based on SSB/CSI-RS (in DL) and SRS (in UL). For example, the terminal may receive an SSB/CSI-RS (S714). SSB/CSI-RS may be used by the UE to generate a beam/CSI report. Meanwhile, the base station may request a beam/CSI report from the terminal through DCI (S716). In this case, the UE may generate a beam/CSI report based on the SSB/CSI-RS, and transmit the generated beam/CSI report to the base station through PUSCH/PUCCH (S718). The beam/CSI report may include a beam measurement result, information on a preferred beam, and the like. The base station and the terminal may switch the beam based on the beam/CSI report (S720a, S720b).

Thereafter, the terminal and the base station may perform the procedures and/or methods described/suggested above. For example, the terminal and the base station process the information in the memory according to the present invention based on the configuration information obtained in the network access process (e.g., system information acquisition process, RRC connection process through RACH, etc.) Or may process the received radio signal and store it in a memory. Here, the radio signal may include at least one of a PDCCH, a PDSCH, and a reference signal (RS) in case of a downlink, and may include at least one of a PUCCH, a PUSCH, and an SRS in case of an uplink.

The above description can be basically applied to MTC and NB-IoT in common. The parts that can be different in MTC and NB-IoT will be described further below.

MTC network access process

An MTC network access procedure based on LTE will be further described. The following description can be extended to NR as well. In LTE, the MIB includes 10 reserved bits. In MTC, five MSBs (Most Significant Bits) out of 10 reserved bits in the MIB are used to indicate scheduling information for a System Information Block for bandwidth reduced device (SIB1-BR). Five MSBs are used to indicate the number of repetitions of SIB1-BR and transport block size (TBS). SIB1-BR is transmitted on the PDSCH. SIB1-BR may be unchanged in 512 radio frames (5120 ms) to allow multiple subframes to be combined. The information carried in SIB1-BR is similar to that of SIB1 in the LTE system.

The MTC RACH process is basically the same as the LTE RACH process and differs in the following matters: The MTC RACH process is performed based on the CE (Coverage Enhancement) level. For example, in order to improve PRACH coverage, whether/the number of PRACH repetitive transmissions may be changed for each CE level.

Table 6 exemplifies CE modes/levels supported by MTC. MTC supports two modes (CE mode A and CE mode B) and four levels (levels 1 to 4) for coverage enhancement.

Mode Level Description Mode A Level 1 No repetition Level 2 Small Number of Repetition Mode B Level 3 Medium Number of Repetition Level 4 Large Number of Repetition

CE mode A is a mode for small coverage enhancement in which complete mobility and CSI feedback are supported, and there is no repetition or the number of repetitions may be set to be small. CE mode B is a mode for a terminal with extremely poor coverage conditions supporting CSI feedback and limited mobility, and the number of repetitions may be large.

The base station broadcasts system information including a plurality of (eg, three) RSRP (Reference Signal Received Power) threshold values, and the UE may determine the CE level by comparing the RSRP threshold value with the RSRP measurement value. The following information for each CE level can be independently configured through system information.

-PRACH resource information: PRACH opportunity (opportunity) period / offset, PRACH frequency resource

-Preamble Group: Preamble set allocated for each CE level

-Number of repetitions per preamble attempt, maximum number of preamble attempts

-RAR window time: the length of the time period in which RAR reception is expected (eg, number of subframes)

-Conflict Resolution Window Time: The length of the time period in which the conflict resolution message is expected to be received

After selecting a PRACH resource corresponding to its CE level, the UE may perform PRACH transmission based on the selected PRACH resource. The PRACH waveform used in MTC is the same as the PRACH waveform used in LTE (eg, OFDM and Zadoff-Chu sequence). Signals/messages transmitted after the PRACH may also be repeatedly transmitted, and the number of repetitions may be independently set according to the CE mode/level.

NB-IoT network access process

The NB-IoT network access procedure based on LTE will be further described. The following description can be extended to NR as well. In FIG. 25, PSS, SSS, and PBCH of S2302 are replaced with NPSS, NSSS, and NPBCH in NB-IoT, respectively.

The NB-IoT RACH process is basically the same as the LTE RACH process, and there are differences in the following points. First, the RACH preamble format is different. In LTE, the preamble is based on a code/sequence (eg, zadoff-chu sequence), whereas in NB-IoT, the preamble is a subcarrier. Second, the NB-IoT RACH process is performed based on the CE level. Therefore, PRACH resources are allocated differently for each CE level. Third, since the SR resource is not configured in NB-IoT, the uplink resource allocation request in NB-IoT is performed using the RACH process.

26 illustrates preamble transmission in NB-IoT RACH.

Referring to FIG. 26, the NPRACH preamble is composed of four symbol groups, and each symbol group may be composed of a CP and a plurality of (eg, 5) SC-FDMA symbols. In NR, the SC-FDMA symbol may be replaced with an OFDM symbol or a DFT-s-OFDM symbol. NPRACH only supports single-tone transmission with a 3.75kHz subcarrier interval, and provides CPs of 66.7μs and 266.67μs in length to support different cell radii. Each symbol group performs frequency hopping, and the hopping pattern is as follows. The subcarrier transmitting the first symbol group is determined in a pseudo-random method. The second symbol group performs 1 subcarrier hop, the third symbol group 6 subcarriers hop, and the fourth symbol group 1 subcarrier jump. In the case of repetitive transmission, the frequency hopping procedure is repeatedly applied, and the NPRACH preamble can be repeatedly transmitted {1, 2, 4, 8, 16, 32, 64, 128} times to improve coverage. NPRACH resources can be configured for each CE level. The UE may select an NPRACH resource based on a CE level determined according to a downlink measurement result (eg, RSRP), and transmit a RACH preamble using the selected NPRACH resource. NPRACH may be transmitted on an anchor carrier, or may be transmitted on a non-anchor carrier in which NPRACH resources are configured.

Discontinuous Reception (DRX) operation

The UE may perform the DRX operation while performing the procedures and/or methods described/suggested above. A terminal in which DRX is configured may reduce power consumption by discontinuously receiving a DL signal. DRX may be performed in Radio Resource Control (RRC)_IDLE state, RRC_INACTIVE state, and RRC_CONNECTED state.

RRC_CONNECTED DRX

In the RRC_CONNECTED state, DRX is used for discontinuous reception of PDCCH. For convenience, DRX performed in the RRC_CONNECTED state is referred to as RRC_CONNECTED DRX.

27 illustrates a DRX cycle for discontinuous reception of a PDCCH.

Referring to FIG. 27, the DRX cycle consists of On Duration and Opportunity for DRX. The DRX cycle defines a time interval in which On Duration is periodically repeated. On Duration represents a time period during which the UE monitors to receive the PDCCH (or MPDCCH, NPDCCH). When DRX is configured, the UE performs PDCCH monitoring during On Duration. If there is a PDCCH successfully detected during PDCCH monitoring, the UE operates an inactivity timer and maintains an awake state. On the other hand, if there is no PDCCH successfully detected during PDCCH monitoring, the terminal enters a sleep state after the On Duration is over. Accordingly, when DRX is configured, PDCCH monitoring/reception may be discontinuously performed in the time domain in performing the procedure and/or method described/proposed above. For example, when DRX is configured, PDCCH monitoring in the present invention may be performed discontinuously according to DRX configuration in the activated cell(s). Specifically, PDCCH monitoring is performed when a PDCCH opportunity (e.g., a time interval set to monitor the PDCCH (e.g., one or more consecutive OFDM symbols)) corresponds to On Duration, and when it corresponds to Opportunity for DRX, PDCCH Monitoring can be omitted. On the other hand, when DRX is not set, PDCCH monitoring/reception may be continuously performed in the time domain in performing the procedures and/or methods described/proposed above. For example, when DRX is not set, the PDCCH reception opportunity may be set continuously in the present invention. Meanwhile, regardless of whether or not DRX is set, PDCCH monitoring may be restricted in a time period set as a measurement gap.

Table 7 shows the process of the terminal related to the DRX (RRC_CONNECTED state). Referring to Table 7, DRX configuration information is received through higher layer (eg, RRC) signaling, and whether DRX ON/OFF is controlled by a DRX command of the MAC layer. When DRX is configured, the UE may discontinuously perform PDCCH monitoring in performing the procedures and/or methods described/suggested in the present invention, as illustrated in FIG. 27.

Type of signals UE procedure 1 ^st step RRC signaling (MAC-CellGroupConfig) -Receive DRX configuration information 2 ^nd Step MAC CE ((Long) DRX command MAC CE) -Receive DRX command 3 ^rd Step - -Monitor a PDCCH during an on-duration of a DRX cycle

Here, the MAC-CellGroupConfig includes configuration information required to set a medium access control (MAC) parameter for a cell group. MAC-CellGroupConfig may also include configuration information about DRX. For example, MAC-CellGroupConfig defines DRX, and may include information as follows.

-Value of drx-OnDurationTimer: Defines the length of the start section of the DRX cycle

-Value of drx-InactivityTimer: Defines the length of the time interval in which the UE is awake after the PDCCH opportunity in which the PDCCH indicating initial UL or DL data is detected

-Value of drx-HARQ-RTT-TimerDL: Defines the length of the maximum time interval from receiving the initial DL transmission until the DL retransmission is received.

-Value of drx-HARQ-RTT-TimerDL: After the grant for initial UL transmission is received, the length of the maximum time interval until the grant for UL retransmission is received is defined.

-drx-LongCycleStartOffset: Defines the time length and start point of the DRX cycle

-drx-ShortCycle (optional): Defines the time length of the short DRX cycle

Here, if any one of drx-OnDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is in operation, the UE performs PDCCH monitoring at every PDCCH opportunity while maintaining the awake state.

RRC_IDLE DRX

In the RRC_IDLE state and RRC_INACTIVE state, the DRX is used to receive paging signals discontinuously. For convenience, DRX performed in the RRC_IDLE (or RRC_INACTIVE) state is referred to as RRC_IDLE DRX.

Accordingly, when DRX is configured, PDCCH monitoring/reception may be discontinuously performed in the time domain in performing the procedure and/or method described/proposed above.

28 illustrates a DRX cycle for paging.

Referring to FIG. 28, a DRX may be configured for discontinuous reception of a paging signal. The terminal may receive DRX configuration information from the base station through higher layer (eg, RRC) signaling. DRX configuration information may include configuration information for a DRX cycle, a DRX offset, and a DRX timer. The UE repeats On Duration and Sleep duration according to the DRX cycle. The terminal may operate in a wakeup mode in an On duration and a sleep mode in a Sleep duration. In the wakeup mode, the terminal can monitor the PO to receive a paging message. PO means a time resource/section (eg, subframe, slot) in which the terminal expects to receive a paging message. PO monitoring includes monitoring the PDCCH (or MPDCCH, NPDCCH) scrambled from PO to P-RNTI (hereinafter, paging PDCCH). The paging message may be included in the paging PDCCH or may be included in the PDSCH scheduled by the paging PDCCH. One or more PO(s) are included in a paging frame (PF), and the PF may be periodically set based on the UE ID. Here, the PF corresponds to one radio frame, and the UE ID may be determined based on the International Mobile Subscriber Identity (IMSI) of the terminal. When DRX is configured, the terminal monitors only one PO per DRX cycle. When the terminal receives a paging message instructing to change its ID and/or system information from the PO, it performs a RACH process to initialize (or reset) connection with the base station, or receives new system information from the base station ( Or obtain). Therefore, in performing the above-described/suggested procedure and/or method, the PO monitoring may be performed discontinuously in the time domain to perform RACH for connection with the base station or to receive (or acquire) new system information from the base station. I can.

29 illustrates an extended DRX (eDRX) cycle.

According to the DRX cycle configuration, the maximum cycle duration may be limited to 2.56 seconds. However, in the case of a terminal in which data transmission and reception is intermittently performed, such as an MTC terminal or an NB-IoT terminal, unnecessary power consumption may occur during a DRX cycle. In order to further reduce the power consumption of the terminal, a method of significantly extending the DRX cycle based on power saving mode (PSM) and paging time window or paging transmission window (PTW) has been introduced, and the extended DRX cycle is simply referred to as the eDRX cycle. . Specifically, Paging Hyper-frames (PH) are periodically configured based on the UE ID, and PTWs are defined in the PH. The terminal may perform a DRX cycle in the PTW duration to switch to the wakeup mode in its PO to monitor the paging signal. In the PTW period, one or more DRX cycles (eg, wake-up mode and sleep mode) of FIG. 28 may be included. The number of DRX cycles in the PTW period may be configured by the base station through an upper layer (eg, RRC) signal.

Wake-Up Signal (WUS)

In MTC and NB-IoT, WUS can be used to reduce power consumption related to paging monitoring. WUS is a physical layer signal indicating whether or not the UE monitors a paging signal (eg, MPDCCH/NPDCCH scrambled with P-RNTI) according to the cell configuration. In the case of a terminal in which eDRX is not configured (ie, only DRX is configured), WUS may be associated with one PO (N=1). On the other hand, in the case of a terminal configured with eDRX, WUS may be associated with one or more POs (N≥1). When WUS is detected, the terminal may monitor N POs after being associated with WUS. On the other hand, if WUS is not detected, the terminal may maintain the sleep mode by omitting PO monitoring until the next WUS is monitored.

30 illustrates a timing relationship between WUS and PO.

The terminal may receive configuration information for WUS from the base station and monitor WUS based on the WUS configuration information. The configuration information for WUS may include, for example, a maximum WUS duration, the number of consecutive POs related to WUS, and gap information. The maximum WUS period represents the maximum time period in which WUS can be transmitted, and may be expressed as a ratio of the maximum number of repetitions (eg, Rmax) related to the PDCCH (eg, MPDCCH, NPDCCH). The terminal may expect repeated WUS transmission within the maximum WUS interval, but the actual number of WUS transmissions may be less than the maximum number of WUS transmissions within the maximum WUS interval. For example, for a terminal within good coverage, the number of WUS repetitions may be small. For convenience, a resource/opportunity through which WUS can be transmitted within the maximum WUS interval is referred to as a WUS resource. The WUS resource may be defined as a plurality of consecutive OFDM symbols and a plurality of consecutive subcarriers. The WUS resource may be defined as a plurality of consecutive OFDM symbols and a plurality of consecutive subcarriers in a subframe or slot. For example, the WUS resource may be defined as 14 consecutive OFDM symbols and 12 consecutive subcarriers. A terminal that detects WUS does not monitor WUS until the first PO associated with WUS. If WUS is not detected during the maximum WUS period, the terminal does not monitor the paging signal in POs associated with WUS (or remains in sleep mode).

Communication system example to which the present invention is applied

Although not limited thereto, various descriptions, functions, procedures, proposals, methods, and/or operational flow charts of the present invention disclosed in this document may be applied to various fields requiring wireless communication/connection (eg, 5G) between devices. have.

Hereinafter, it will be illustrated in more detail with reference to the drawings. In the following drawings/description, the same reference numerals may exemplify the same or corresponding hardware block, software block, or functional block, unless otherwise indicated.

31 illustrates a communication system 1 applied to the present invention.

Referring to Fig. 31, a communication system 1 applied to the present invention includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (eg, 5G NR (New RAT), LTE (Long Term Evolution)), and may be referred to as a communication/wireless/5G device. Although not limited thereto, wireless devices include robots 100a, vehicles 100b-1 and 100b-2, eXtended Reality (XR) devices 100c, hand-held devices 100d, and home appliances 100e. ), an Internet of Thing (IoT) device 100f, and an AI device/server 400. For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, and a vehicle capable of performing inter-vehicle communication. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (eg, a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, including HMD (Head-Mounted Device), HUD (Head-Up Display), TV, smartphone, It can be implemented in the form of a computer, wearable device, home appliance, digital signage, vehicle, robot, and the like. Portable devices may include smart phones, smart pads, wearable devices (eg, smart watches, smart glasses), computers (eg, notebook computers, etc.). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors, smart meters, and the like. For example, the base station and the network may be implemented as a wireless device, and the specific wireless device 200a may operate as a base station/network node to another wireless device.

The wireless devices 100a to 100f may be connected to the network 300 through the base station 200. AI (Artificial Intelligence) technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI server 400 through the network 300. The network 300 may be configured using a 3G network, a 4G (eg, LTE) network, or a 5G (eg, NR) network. The wireless devices 100a to 100f may communicate with each other through the base station 200 / network 300, but may perform direct communication (e.g. sidelink communication) without going through the base station / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g. V2V (Vehicle to Vehicle)/V2X (Vehicle to Everything) communication). In addition, the IoT device (eg, sensor) may directly communicate with other IoT devices (eg, sensors) or other wireless devices 100a to 100f.

Wireless communication/connections 150a, 150b, and 150c may be established between the wireless devices 100a to 100f / base station 200 and the base station 200 / base station 200. Here, the wireless communication/connection includes various wireless access such as uplink/downlink communication 150a, sidelink communication 150b (or D2D communication), base station communication 150c (eg relay, Integrated Access Backhaul). This can be achieved through technology (eg 5G NR) Through wireless communication/connections 150a, 150b, 150c, the wireless device and the base station/wireless device, and the base station and the base station can transmit/receive radio signals to each other. For example, the wireless communication/connection 150a, 150b, 150c can transmit/receive signals through various physical channels. To this end, based on various proposals of the present invention, for transmission/reception of wireless signals At least some of a process of setting various configuration information, various signal processing processes (eg, channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.), resource allocation process, and the like may be performed.

Examples of wireless devices to which the present invention is applied

32 illustrates a wireless device applicable to the present invention.

Referring to FIG. 32, the first wireless device 100 and the second wireless device 200 may transmit and receive wireless signals through various wireless access technologies (eg, LTE and NR). Here, {the first wireless device 100, the second wireless device 200} is the {wireless device 100x, the base station 200} and/or {wireless device 100x, wireless device 100x) of FIG. 32 } Can be matched.

The first wireless device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and/or one or more antennas 108. The processor 102 controls the memory 104 and/or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed herein. For example, the processor 102 may process information in the memory 104 to generate first information/signal, and then transmit a radio signal including the first information/signal through the transceiver 106. In addition, the processor 102 may store information obtained from signal processing of the second information/signal in the memory 104 after receiving a radio signal including the second information/signal through the transceiver 106. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may perform some or all of the processes controlled by the processor 102, or instructions for performing the descriptions, functions, procedures, suggestions, methods, and/or operational flow charts disclosed in this document. It can store software code including Here, the processor 102 and the memory 104 may be part of a communication modem/circuit/chip designed to implement wireless communication technology (eg, LTE, NR). The transceiver 106 may be coupled with the processor 102 and may transmit and/or receive radio signals through one or more antennas 108. The transceiver 106 may include a transmitter and/or a receiver. The transceiver 106 may be mixed with an RF (Radio Frequency) unit. In the present invention, the wireless device may mean a communication modem/circuit/chip.

The second wireless device 200 includes one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and/or one or more antennas 208. The processor 202 controls the memory 204 and/or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed herein. For example, the processor 202 may process information in the memory 204 to generate third information/signal, and then transmit a wireless signal including the third information/signal through the transceiver 206. In addition, the processor 202 may store information obtained from signal processing of the fourth information/signal in the memory 204 after receiving a radio signal including the fourth information/signal through the transceiver 206. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may perform some or all of the processes controlled by the processor 202, or instructions for performing the descriptions, functions, procedures, suggestions, methods and/or operational flow charts disclosed in this document. It can store software code including Here, the processor 202 and the memory 204 may be part of a communication modem/circuit/chip designed to implement wireless communication technology (eg, LTE, NR). The transceiver 206 may be connected to the processor 202 and may transmit and/or receive radio signals through one or more antennas 208. The transceiver 206 may include a transmitter and/or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present invention, the wireless device may mean a communication modem/circuit/chip.

Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (eg, functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 may be configured to generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Units (SDUs) according to the description, functions, procedures, proposals, methods, and/or operational flow charts disclosed in this document. Can be generated. One or more processors 102, 202 may generate messages, control information, data, or information according to the description, function, procedure, suggestion, method, and/or operational flow chart disclosed herein. At least one processor (102, 202) generates a signal (e.g., a baseband signal) including PDU, SDU, message, control information, data or information according to the functions, procedures, proposals and/or methods disclosed herein. , It may be provided to one or more transceivers (106, 206). One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206, and the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein PDUs, SDUs, messages, control information, data, or information may be obtained according to the parameters.

One or more of the processors 102 and 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more of the processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) May be included in one or more processors 102 and 202. The description, functions, procedures, suggestions, methods, and/or operational flow charts disclosed in this document may be implemented using firmware or software, and firmware or software may be implemented to include modules, procedures, functions, and the like. The description, functions, procedures, proposals, methods and/or operational flow charts disclosed in this document are included in one or more processors 102, 202, or stored in one or more memories 104, 204, and are It may be driven by the above processors 102 and 202. The descriptions, functions, procedures, proposals, methods and/or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and/or a set of instructions.

One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and may store various types of data, signals, messages, information, programs, codes, instructions and/or instructions. One or more memories 104 and 204 may be composed of ROM, RAM, EPROM, flash memory, hard drive, register, cache memory, computer readable storage medium, and/or combinations thereof. One or more memories 104 and 204 may be located inside and/or outside of one or more processors 102 and 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various technologies such as wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, control information, radio signals/channels, and the like mentioned in the methods and/or operation flow charts of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, radio signals/channels, etc. mentioned in the description, functions, procedures, suggestions, methods and/or operation flow charts disclosed in this document from one or more other devices. have. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202, and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or radio signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or radio signals from one or more other devices. In addition, one or more transceivers (106, 206) may be connected with one or more antennas (108, 208), and one or more transceivers (106, 206) through one or more antennas (108, 208), the description and functionality disclosed in this document. It may be set to transmit and receive user data, control information, radio signals/channels, and the like mentioned in a procedure, a proposal, a method and/or an operation flowchart. In this document, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (eg, antenna ports). One or more transceivers (106, 206) in order to process the received user data, control information, radio signal / channel, etc. using one or more processors (102, 202), the received radio signal / channel, etc. in the RF band signal. It can be converted into a baseband signal. One or more transceivers 106 and 206 may convert user data, control information, radio signals/channels, etc. processed using one or more processors 102 and 202 from a baseband signal to an RF band signal. To this end, one or more of the transceivers 106 and 206 may include (analog) oscillators and/or filters.

Signal processing circuit example to which the present invention is applied

33 illustrates a signal processing circuit for a transmission signal.

Referring to FIG. 33, the signal processing circuit 1000 may include a scrambler 1010, a modulator 1020, a layer mapper 1030, a precoder 1040, a resource mapper 1050, and a signal generator 1060. have. Although not limited thereto, the operations/functions of FIG. 33 may be performed in the processors 102 and 202 and/or the transceivers 106 and 206 of FIG. 32. The hardware elements of FIG. 33 may be implemented in the processors 102 and 202 and/or the transceivers 106 and 206 of FIG. 32. For example, blocks 1010 to 1060 may be implemented in the processors 102 and 202 of FIG. 32. Further, blocks 1010 to 1050 may be implemented in the processors 102 and 202 of FIG. 32, and block 1060 may be implemented in the transceivers 106 and 206 of FIG. 32.

The codeword may be converted into a wireless signal through the signal processing circuit 1000 of FIG. 33. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transport block (eg, a UL-SCH transport block, a DL-SCH transport block). The radio signal may be transmitted through various physical channels (eg, PUSCH, PDSCH).

Specifically, the codeword may be converted into a scrambled bit sequence by the scrambler 1010. The scramble sequence used for scramble is generated based on an initialization value, and the initialization value may include ID information of a wireless device. The scrambled bit sequence may be modulated by the modulator 1020 into a modulation symbol sequence. The modulation scheme may include pi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying (m-PSK), m-Quadrature Amplitude Modulation (m-QAM), and the like. The complex modulation symbol sequence may be mapped to one or more transport layers by the layer mapper 1030. The modulation symbols of each transport layer may be mapped to the corresponding antenna port(s) by the precoder 1040 (precoding). The output z of the precoder 1040 can be obtained by multiplying the output y of the layer mapper 1030 by the N*M precoding matrix W. Here, N is the number of antenna ports, and M is the number of transmission layers. Here, the precoder 1040 may perform precoding after performing transform precoding (eg, DFT transform) on complex modulation symbols. Also, the precoder 1040 may perform precoding without performing transform precoding.

The resource mapper 1050 may map modulation symbols of each antenna port to a time-frequency resource. The time-frequency resource may include a plurality of symbols (eg, CP-OFDMA symbols, DFT-s-OFDMA symbols) in the time domain, and may include a plurality of subcarriers in the frequency domain. The signal generator 1060 generates a radio signal from the mapped modulation symbols, and the generated radio signal may be transmitted to another device through each antenna. To this end, the signal generator 1060 may include an Inverse Fast Fourier Transform (IFFT) module and a Cyclic Prefix (CP) inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, and the like. .

The signal processing process for the received signal in the wireless device may be configured as the reverse of the signal processing process 1010 to 1060 of FIG. 33. For example, a wireless device (eg, 100, 200 in FIG. 32) may receive a wireless signal from the outside through an antenna port/transmitter. The received radio signal may be converted into a baseband signal through a signal restorer. To this end, the signal restorer may include a frequency downlink converter, an analog-to-digital converter (ADC), a CP canceller, and a Fast Fourier Transform (FFT) module. Thereafter, the baseband signal may be reconstructed into a codeword through a resource de-mapper process, a postcoding process, a demodulation process, and a de-scramble process. The codeword may be restored to an original information block through decoding. Accordingly, a signal processing circuit (not shown) for a received signal may include a signal restorer, a resource demapper, a postcoder, a demodulator, a descrambler, and a decoder.

Examples of wireless devices to which the present invention is applied

34 shows another example of a wireless device applied to the present invention. The wireless device may be implemented in various forms according to use-examples/services (see FIG. 32).

Referring to FIG. 34, the wireless devices 100 and 200 correspond to the wireless devices 100 and 200 of FIG. 32, and various elements, components, units/units, and/or modules ) Can be composed of. For example, the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and an additional element 140. The communication unit may include a communication circuit 112 and a transceiver(s) 114. For example, the communication circuit 112 may include one or more processors 102 and 202 and/or one or more memories 104 and 204 of FIG. 32. For example, the transceiver(s) 114 may include one or more transceivers 106,206 and/or one or more antennas 108,208 of FIG. 32. The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional element 140 and controls all operations of the wireless device. For example, the controller 120 may control the electrical/mechanical operation of the wireless device based on the program/code/command/information stored in the memory unit 130. In addition, the control unit 120 transmits the information stored in the memory unit 130 to an external (eg, other communication device) through the communication unit 110 through a wireless/wired interface, or through the communication unit 110 to the outside (eg, Information received through a wireless/wired interface from another communication device) may be stored in the memory unit 130.

The additional element 140 may be variously configured according to the type of wireless device. For example, the additional element 140 may include at least one of a power unit/battery, an I/O unit, a driving unit, and a computing unit. Although not limited to this, wireless devices include robots (Figs. (Fig. W1, 100e), IoT device (Fig. W1, 100f), digital broadcasting terminal, hologram device, public safety device, MTC device, medical device, fintech device (or financial device), security device, climate/environment device, It may be implemented in the form of an AI server/device (FIGS. W1 and 400), a base station (FIGS. W1 and 200), and a network node. The wireless device can be used in a mobile or fixed location depending on the use-example/service.

In FIG. 34, various elements, components, units/units, and/or modules in the wireless devices 100 and 200 may be entirely interconnected through a wired interface, or at least some may be wirelessly connected through the communication unit 110. For example, in the wireless devices 100 and 200, the control unit 120 and the communication unit 110 are connected by wire, and the control unit 120 and the first unit (eg, 130, 140) are connected through the communication unit 110. Can be connected wirelessly. In addition, each element, component, unit/unit, and/or module in the wireless device 100 and 200 may further include one or more elements. For example, the controller 120 may be configured with one or more processor sets. For example, the control unit 120 may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphic processing processor, and a memory control processor. As another example, the memory unit 130 includes random access memory (RAM), dynamic RAM (DRAM), read only memory (ROM), flash memory, volatile memory, and non-volatile memory. volatile memory) and/or a combination thereof.

Hereinafter, an implementation example of FIG. 34 will be described in more detail with reference to the drawings.

Examples of mobile devices to which the present invention is applied

35 illustrates a portable device applied to the present invention. Portable devices may include smart phones, smart pads, wearable devices (eg, smart watches, smart glasses), and portable computers (eg, notebook computers). The portable device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

Referring to FIG. 35, the portable device 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a memory unit 130, a power supply unit 140a, an interface unit 140b, and an input/output unit 140c. ) Can be included. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110 to 130/140a to 140c correspond to blocks 110 to 130/140 of FIG. X3, respectively.

The communication unit 110 may transmit and receive signals (eg, data, control signals, etc.) with other wireless devices and base stations. The controller 120 may perform various operations by controlling components of the portable device 100. The controller 120 may include an application processor (AP). The memory unit 130 may store data/parameters/programs/codes/commands required for driving the portable device 100. Also, the memory unit 130 may store input/output data/information, and the like. The power supply unit 140a supplies power to the portable device 100 and may include a wired/wireless charging circuit, a battery, and the like. The interface unit 140b may support connection between the portable device 100 and other external devices. The interface unit 140b may include various ports (eg, audio input/output ports, video input/output ports) for connection with external devices. The input/output unit 140c may receive or output image information/signal, audio information/signal, data, and/or information input from a user. The input/output unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and/or a haptic module.

For example, in the case of data communication, the input/output unit 140c acquires information/signals (eg, touch, text, voice, image, video) input from the user, and the obtained information/signals are stored in the memory unit 130. Can be saved. The communication unit 110 may convert information/signals stored in the memory into wireless signals, and may directly transmit the converted wireless signals to other wireless devices or to a base station. In addition, after receiving a radio signal from another radio device or a base station, the communication unit 110 may restore the received radio signal to the original information/signal. After the restored information/signal is stored in the memory unit 130, it may be output in various forms (eg, text, voice, image, video, heptic) through the input/output unit 140c.

Examples of vehicles or autonomous vehicles to which the present invention is applied

36 illustrates a vehicle or an autonomous vehicle applied to the present invention. The vehicle or autonomous vehicle may be implemented as a mobile robot, a vehicle, a train, an aerial vehicle (AV), or a ship.

Referring to FIG. 36, a vehicle or autonomous vehicle 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and autonomous driving. It may include a unit (140d). The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110/130/140a to 140d correspond to blocks 110/130/140 of FIG. X3, respectively.

The communication unit 110 may transmit and receive signals (eg, data, control signals, etc.) with external devices such as other vehicles, base stations (e.g. base stations, roadside base stations, etc.), and servers. The controller 120 may perform various operations by controlling elements of the vehicle or the autonomous vehicle 100. The control unit 120 may include an Electronic Control Unit (ECU). The driving unit 140a may cause the vehicle or the autonomous vehicle 100 to travel on the ground. The driving unit 140a may include an engine, a motor, a power train, a wheel, a brake, a steering device, and the like. The power supply unit 140b supplies power to the vehicle or the autonomous vehicle 100, and may include a wired/wireless charging circuit, a battery, and the like. The sensor unit 140c may obtain vehicle status, surrounding environment information, user information, and the like. The sensor unit 140c is an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, and a vehicle advancement. /Reverse sensor, battery sensor, fuel sensor, tire sensor, steering sensor, temperature sensor, humidity sensor, ultrasonic sensor, illumination sensor, pedal position sensor, etc. may be included. The autonomous driving unit 140d is a technology for maintaining a driving lane, a technology for automatically adjusting the speed such as adaptive cruise control, a technology for automatically driving along a predetermined route, and for driving by automatically setting a route when a destination is set. Technology, etc. can be implemented.

For example, the communication unit 110 may receive map data and traffic information data from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan based on the acquired data. The controller 120 may control the driving unit 140a so that the vehicle or the autonomous driving vehicle 100 moves along the autonomous driving path according to the driving plan (eg, speed/direction adjustment). During autonomous driving, the communication unit 110 asynchronously/periodically acquires the latest traffic information data from an external server, and may acquire surrounding traffic information data from surrounding vehicles. In addition, during autonomous driving, the sensor unit 140c may acquire vehicle state and surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and the driving plan based on the newly acquired data/information. The communication unit 110 may transmit information about a vehicle location, an autonomous driving route, and a driving plan to an external server. The external server may predict traffic information data in advance using AI technology or the like, based on information collected from the vehicle or autonomous vehicles, and may provide the predicted traffic information data to the vehicle or autonomous vehicles.

The embodiments described above are those in which components 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. In addition, it is also possible to constitute an embodiment of the present invention by combining some components and/or features. The order of operations described in the embodiments of the present invention may be changed. Some configurations or features of one embodiment may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is obvious that the embodiments may be configured by combining claims that do not have an explicit citation relationship in the claims or may be included as new claims by amendment after filing.

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

The embodiment 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 is one or more ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, etc.

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, or function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor through various known means.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the features of the present invention. Therefore, the detailed description above should not be construed as restrictive in all respects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes 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.

Claims (15)

In a method for transmitting and receiving a signal by a terminal in a wireless communication system, Receiving a call message for calling a terminal in an idle state from a base station; Transmitting a response message for receiving downlink data to the base station based on the received call message; And Including the step of receiving the downlink data from the base station, The call message includes information on a plurality of resources set to the terminal for transmission of the response message, The response message is transmitted based on a resource selected by the terminal among the plurality of resources. The method of claim 1, The response message is transmitted through a resource selected based on information on channel quality between the terminal and the base station, among the plurality of resources. The method of claim 2, The information on the channel quality between the terminal and the base station includes information on the CE (Coverage Enhancement) level. The method of claim 1, The response message is transmitted through Narrowband Physical Uplink Control Channel (NPUCCH), Narrowband Physical Uplink Shared Channel (NPUSCH), or Narrow Physical Random Access Channel (NPRACH). The method of claim 1, The message for invoking the terminal comprises a paging message. The method of claim 1, wherein receiving the downlink data comprises: By monitoring a search space corresponding to the selected resource, Including, receiving the downlink data. In a terminal operating in a wireless communication system, A transceiver; And Including a processor, The processor, Receiving a message for calling the terminal in the idle state from the base station, Based on the received message, transmit a response message for receiving downlink data to the base station, Receiving the downlink data from the base station, The message for calling the terminal includes information on a plurality of resources set for the terminal for transmission of the response message, The response message is transmitted based on a resource selected by the terminal from among the plurality of resources. The method of claim 7, The response message is transmitted through a resource selected based on information on a channel quality between the terminal and the base station, among the plurality of resources. The method of claim 8, The information on the channel quality between the terminal and the base station includes a CE (Coverage Enhancement) level. The method of claim 7, The response message is transmitted through a narrowband physical uplink control channel (NPUCCH), a narrowband physical uplink shared channel (NPUSCH), or a narrow physical random access channel (NPRACH). The method of claim 7, The message for invoking the terminal includes a paging message. In the device for the terminal, At least one processor; And And at least one computer memory operatively connected to the at least one processor and allowing the at least one processor to perform an operation when executed, the operation comprising: Receiving a message for calling the terminal in the idle state from the base station, Based on the received message, transmit a response message for receiving downlink data to the base station, Receiving the downlink data from the base station, The message for calling the terminal includes information on a plurality of resources set for the terminal for transmission of the response message, The response message is transmitted based on a resource selected by the terminal from among the plurality of resources. The method of claim 12, The response message is transmitted through a resource selected based on information on a channel quality between the terminal and the base station among the plurality of resources. The method of claim 13, The information on the channel quality between the terminal and the base station, including a CE (Coverage Enhancement) level, apparatus. The method of claim 12, The response message is transmitted through Narrowband Physical Uplink Control Channel (NPUCCH), Narrowband Physical Uplink Shared Channel (NPUSCH), or Narrow Physical Random Access Channel (NPRACH).

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