KR20220077868A - Method and apparatus for coverage enhancement of terminal in communication system - Google Patents

Abstract

Disclosed are a method and an apparatus for improving coverage of a terminal in a communication system. The operating method of the base station includes generating first RACH configuration information for a general terminal, generating second RACH configuration information for a RedCap terminal, the first RACH configuration information and the second RACH configuration information Transmitting a message, and performing a random access procedure with the first terminal based on the message.

Description

Method and apparatus for improving the coverage of a terminal in a communication system

The present invention relates to a technology for improving terminal coverage in a communication system, and more particularly, to a technology for improving coverage for a terminal having reduced capability.

For processing of rapidly increasing wireless data, a frequency band (eg, 6 GHz) higher than a frequency band (eg, a frequency band of 6 GHz or less) of a long term evolution (LTE) communication system (or LTE-A communication system) A communication system (eg, a new radio (NR) communication system) using the above frequency bands) is being considered. The NR system may support a frequency band of 6 GHz or less as well as a frequency band of 6 GHz or higher, and may support various communication services and scenarios compared to the LTE system. In addition, the requirements of the NR system may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), massive Machine Type Communication (mMTC), and the like.

Meanwhile, a terminal (hereinafter, referred to as a “RedCap terminal”) having reduced capability in a communication system may be introduced. The maximum carrier bandwidth and the number of reception antennas for the RedCap terminal may be reduced compared to the existing terminal, and thus the coverage of the RedCap terminal may be reduced. Therefore, there is a need for methods for improving the coverage of the RedCap terminal. In addition, the RedCap terminal and the normal terminal can perform a random access procedure, and methods for distinguishing the RedCap terminal from the normal terminal in the random access procedure are needed.

An object of the present invention for solving the above problems is to provide a method and an apparatus for improving the coverage of a terminal having reduced capability (reduced capability).

In order to achieve the above object, a method of operating a base station according to a first embodiment of the present invention includes generating first RACH configuration information for a general terminal, generating second RACH configuration information for a RedCap terminal, and the Transmitting a message including the first RACH configuration information and the second RACH configuration information, and performing a random access procedure with a first terminal based on the message, wherein the terminal type of the first terminal is It is confirmed based on the first RACH configuration information and the second RACH configuration information, and the terminal type is the general terminal or the RedCap terminal.

The first RACH configuration information may include configuration information of a first PRACH preamble for the general terminal, and the second RACH configuration information may include configuration information of a second PRACH preamble for the RedCap terminal, The terminal type may be identified based on a type of a PRACH preamble received in the random access procedure, and the type of the PRACH preamble may be the first PRACH preamble or the second PRACH preamble.

The first RACH configuration information may include configuration information of a first RO for the general terminal, and the second RACH configuration information may include configuration information of a second RO for the RedCap terminal, and the terminal A type may be identified based on a type of an RO from which a PRACH preamble is received in the random access procedure, and the type of the RO may be the first RO or the second RO.

Information for enabling or disabling the operation of distinguishing the normal terminal from the RedCap terminal based on the first RACH configuration information and the second RACH configuration information may be included in the message.

Information indicating whether at least one of the Type-1 random access procedure and the Type-2 random access procedure is supported may be included in the message.

The performing the random access procedure includes: receiving Msg1 from the first terminal; transmitting Msg2 to the first terminal in response to the Msg1; receiving Msg3 from the first terminal; and The method may include identifying the terminal type as the general terminal or the RedCap terminal based on the indicator included in the Msg3.

Information for enabling or disabling the operation of distinguishing the normal terminal from the RedCap terminal based on the indicator may be included in the message.

The step of performing the random access procedure includes: receiving MsgA including a PRACH preamble and a PUSCH from the first terminal, and confirming the terminal type as the general terminal or the RedCap terminal based on the transmission resource of the PUSCH may include the step of

The step of performing the random access procedure includes receiving MsgA including a PRACH preamble and a PUSCH from the first terminal, and setting the terminal type to the general terminal or the RedCap terminal based on the indicator included in the PUSCH. It may include a step of verifying.

The step of performing the random access procedure includes: receiving a PRACH preamble from the first terminal that is the RedCap terminal; calculating a second RNTI based on a transmission resource of the PRACH preamble; and by the second RNTI The method may include transmitting the DCI to be scrambled to the RedCap terminal, and the value of the second RNTI may be a result of a second equation in which an offset is applied to the first equation for calculating the first RNTI of the normal terminal. have.

The offset may be 14×80×8×4.

In order to prevent the value of the second RNTI from deviating from a preset range due to the offset, a modular operation may be applied to the second equation.

The second RNTI may be an RA-R-RNTI for a Type-1 random access procedure or an MSGB-R-RNTI for a Type-2 random access procedure.

A base station according to a second embodiment of the present invention for achieving the above object includes a processor, a memory in electronic communication with the processor, and instructions stored in the memory, when the instructions are executed by the processor , the commands include the base station generating first RACH configuration information for a general terminal, generating second RACH configuration information for a RedCap terminal, and including the first RACH configuration information and the second RACH configuration information send a message, and cause to perform a random access procedure with a first terminal based on the message, wherein the terminal type of the first terminal is based on the first RACH configuration information and the second RACH configuration information is confirmed, and the terminal type is the general terminal or the RedCap terminal.

The first RACH configuration information may include configuration information of a first PRACH preamble for the general terminal, and the second RACH configuration information may include configuration information of a second PRACH preamble for the RedCap terminal, The terminal type may be identified based on a type of a PRACH preamble received in the random access procedure, and the type of the PRACH preamble may be the first PRACH preamble or the second PRACH preamble.

The first RACH configuration information may include configuration information of a first RO for the general terminal, and the second RACH configuration information may include configuration information of a second RO for the RedCap terminal, and the terminal A type may be identified based on a type of an RO from which a PRACH preamble is received in the random access procedure, and the type of the RO may be the first RO or the second RO.

When performing the random access procedure, the commands indicate that the base station receives Msg1 from the first terminal, transmits Msg2 to the first terminal in response to the Msg1, and receives Msg3 from the first terminal and confirming the terminal type as the general terminal or the RedCap terminal based on the indicator included in the Msg3.

When performing the random access procedure, the instructions indicate that the base station receives MsgA including a PRACH preamble and a PUSCH from the first terminal, and sets the terminal type based on the transmission resource of the PUSCH to the general terminal or operable to cause an acknowledgment with the RedCap terminal.

In the case of performing the random access procedure, the commands indicate that the base station receives MsgA including a PRACH preamble and a PUSCH from the first terminal, and sets the terminal type based on an indicator included in the PUSCH to the general terminal or to cause confirmation with the RedCap terminal.

When performing the random access procedure, the instructions are that the base station receives a PRACH preamble from the first terminal that is the RedCap terminal, calculates a second RNTI based on the transmission resource of the PRACH preamble, and the second It can operate to cause the DCI scrambled by 2 RNTIs to be transmitted to the RedCap UE, and the value of the second RNTI is a second equation in which an offset is applied to a first equation for calculating the first RNTI of the normal UE. It can be the result of an expression.

According to the present application, first RACH (random access channel) configuration information for a general terminal and second RACH configuration information for a reduced capability (RedCap) terminal may be independently configured. The general terminal may perform a random access procedure based on the first RACH configuration information, and the RedCap terminal may perform a random access procedure based on the second RACH configuration information. The base station may distinguish the normal terminal from the RedCap terminal based on the first RACH configuration information and/or the second RACH configuration information in the random access procedure. The base station may limit the random access procedure of the RedCap terminal if necessary. Accordingly, the communication system can be efficiently operated.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a type 1 frame structure.
4 is a conceptual diagram illustrating a first embodiment of a type 2 frame structure.
5 is a conceptual diagram illustrating a first embodiment of a method for transmitting an SS/PBCH block in a communication system.
6 is a conceptual diagram illustrating a first embodiment of an SS/PBCH block in a communication system.
7 is a conceptual diagram illustrating a second embodiment of a method for transmitting an SS/PBCH block in a communication system.
8A is a conceptual diagram illustrating an RMSI CORESET mapping pattern #1 in a communication system.
8B is a conceptual diagram illustrating RMSI CORESET mapping pattern #2 in a communication system.
8C is a conceptual diagram illustrating RMSI CORESET mapping pattern #3 in a communication system.
9 is a conceptual diagram illustrating embodiments of a method for multiplexing a control channel and a data channel in sidelink communication.
10 is a conceptual diagram illustrating a first embodiment of a method for scheduling a frequency resource for RedCap SIB1.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”.

In embodiments of the present application, (re)transmission may mean “transmission”, “retransmission”, or “transmission and retransmission”, and (re)setup means “setup”, “reset”, or “set and may mean “reset”, (re)connection may mean “connection”, “reconnection”, or “connection and reconnection”, and (re)connection means “connection”, “reconnection”, or “connection” connection and reconnection”.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the content described below, and the embodiments according to the present invention can be applied to various communication systems. Here, a communication system may be used in the same sense as a communication network (network).

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 is a core network (core network) (eg, S-GW (serving-gateway), P-GW (packet data network (PDN)-gateway), MME (mobility management entity)) may include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network is an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), etc. may include

The plurality of communication nodes 110 to 130 may support a communication protocol (eg, an LTE communication protocol, an LTE-A communication protocol, an NR communication protocol, etc.) defined in a 3rd generation partnership project (3GPP) standard. A plurality of communication nodes 110 to 130 are CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division) technology multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA Technology, Non-orthogonal Multiple Access (NOMA) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each of the components included in the communication node 200 may not be connected to the common bus 270 but to the processor 210 through an individual interface or an individual bus. For example, the processor 210 may be connected to at least one of the memory 220 , the transceiver 230 , the input interface device 240 , the output interface device 250 , and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110 - 1 , 110 - 2 , 110 - 3 , 120 - 1 and 120 - 2 , and a plurality of terminals 130 - 1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB (NB), an evolved NodeB (eNB), gNB, an advanced base station (ABS), HR - BS (high reliability-base station), BTS (base transceiver station), radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), RAS (radio access station) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 includes a user equipment (UE), a terminal equipment (TE), an advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link. , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminals 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and a signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or , Proximity Services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), and the like may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is the base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and corresponding operations, and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal based on the SU-MIMO method. A signal may be received from the second base station 110 - 2 . Alternatively, the second base station 110 - 2 may transmit a signal to the fourth terminal 130 - 4 and the fifth terminal 130 - 5 based on the MU-MIMO scheme, and the fourth terminal 130 - 4 . and each of the fifth terminals 130 - 5 may receive a signal from the second base station 110 - 2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and the fourth The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a terminal 130-1, 130-2, 130-3, 130-4 belonging to its own cell coverage. , 130-5, 130-6) and the CA method can transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Meanwhile, the communication system may support three types of frame structures. The type 1 frame structure may be applied to a frequency division duplex (FDD) communication system, the type 2 frame structure may be applied to a time division duplex (TDD) communication system, and the type 3 frame structure may be applied to an unlicensed band-based communication system (eg, For example, it may be applied to a licensed assisted access (LAA) communication system.

3 is a conceptual diagram illustrating a first embodiment of a type 1 frame structure.

Referring to FIG. 3 , a radio frame 300 may include 10 subframes, and the subframe may include two slots. Accordingly, the radio frame 300 may include 20 slots (eg, slot #0, slot #1, slot #2, slot #3, ..., slot #18, slot #19). The length of the radio frame 300 (T _f ) may be 10 ms (millisecond), the subframe length may be 1 ms, and the slot length (T _slot ) may be 0.5 ms. Here, T _s may indicate a sampling time, and may be 1/30,720,000s (second).

A slot may be composed of a plurality of OFDM symbols in the time domain and may be composed of a plurality of resource blocks (RBs) in the frequency domain. A resource block may be composed of a plurality of subcarriers in the frequency domain. The number of OFDM symbols constituting a slot may vary according to the configuration of a cyclic prefix (CP). The CP may be classified into a normal CP and an extended CP. When a normal CP is used, a slot may be composed of 7 OFDM symbols, and in this case, a subframe may be composed of 14 OFDM symbols. When the extended CP is used, a slot may be composed of 6 OFDM symbols, and in this case, a subframe may be composed of 12 OFDM symbols.

4 is a conceptual diagram illustrating a first embodiment of a type 2 frame structure.

Referring to FIG. 4 , a radio frame 400 may include two half frames, and a half frame may include five subframes. Accordingly, the radio frame 400 may include 10 subframes. The length of the radio frame 400 (T _f ) may be 10 ms. The length of the half frame may be 5 ms. The subframe length may be 1 ms. Here, T _s may be 1/30,720,000s.

The radio frame 400 may include a downlink subframe, an uplink subframe, and a special subframe. Each of the downlink subframe and the uplink subframe may include two slots. The slot length (T _slot ) may be 0.5 ms. Among the subframes included in the radio frame 400 , each of subframe #1 and subframe #6 may be a special subframe. For example, when the downlink-uplink switching period is 5 ms, the radio frame 400 may include two special subframes. Alternatively, when the downlink-uplink switching period is 10 ms, the radio frame 400 may include one special subframe. The special subframe may include a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).

The downlink pilot time slot may be regarded as a downlink interval, and may be used for cell search of the terminal, time and frequency synchronization acquisition, channel estimation, and the like. The guard period may be used to solve an uplink data transmission interference problem caused by downlink data reception delay. In addition, the guard period may include a time required for switching from the downlink data reception operation to the uplink data transmission operation. The uplink pilot time slot may be used for uplink channel estimation, time and frequency synchronization acquisition, and the like. Transmission of a physical random access channel (PRACH) or a sounding reference signal (SRS) may be performed in an uplink pilot time slot.

Lengths of the downlink pilot time slot, guard period, and uplink pilot time slot included in the special subframe may be variably adjusted as necessary. In addition, the number and position of each of the downlink subframe, the uplink subframe, and the special subframe included in the radio frame 400 may be changed as needed.

In a communication system, a transmission time interval (TTI) may be a basic time unit for transmitting encoded data through a physical layer. A short TTI may be used to support low latency requirements in a communication system. The length of the short TTI may be less than 1 ms. The existing TTI having a length of 1 ms may be referred to as a base TTI or a regular TTI. That is, the basic TTI may consist of one subframe. In order to support transmission in a basic TTI unit, a signal and a channel may be configured in a subframe unit. For example, a cell-specific reference signal (CRS), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), etc. exist for each subframe. can

On the other hand, a synchronization signal (eg, a primary synchronization signal (PSS), a secondary synchronization signal (SSS)) may exist every 5 subframes, and a physical broadcast channel (PBCH) may exist every 10 subframes. And radio frames can be distinguished by SFN, and SFN is a signal having a transmission period longer than one radio frame (eg, a paging signal, a reference signal for channel estimation, a signal indicating channel state information, etc.) can be used to define the transport of The period of the SFN may be 1024.

In the LTE system, the PBCH may be a physical layer channel used for transmission of system information (eg, a master information block (MIB)). The PBCH may be transmitted every 10 subframes. That is, the transmission period of the PBCH may be 10 ms, and the PBCH may be transmitted once in a radio frame. The same MIB may be transmitted during 4 consecutive radio frames, and after 4 consecutive radio frames, the MIB may be changed according to the situation of the LTE system. The transmission period of the same MIB may be referred to as "PBCH TTI", and the PBCH TTI may be 40 ms. That is, the MIB may be changed for each PBCH TTI.

The MIB may be composed of 40 bits. Of the 40 bits constituting the MIB, 3 bits may be used to indicate a system band, 3 bits may be used to indicate PHICH (physical hybrid automatic repeat request (ARQ) indicator channel) related information, and 8 bits are It may be used to indicate the SFN, 10 bits may be set as a reserved bit, and 16 bits may be used for a cyclic redundancy check (CRC).

The SFN that distinguishes the radio frame may consist of a total of 10 bits (B9 to B0), and among the 10 bits, 8 bits (B9 to B2) of the most significant bit (MSB) may be indicated by the PBCH (ie, MIB). . The MSB 8 bits (B9 to B2) of the SFN indicated by the PBCH (ie, MIB) may be the same during four consecutive radio frames (ie, PBCH TTI). The least significant bit (LSB) 2 bits (B1 to B0) of the SFN may be changed during 4 consecutive radio frames (ie, PBCH TTI), and may not be explicitly indicated by the PBCH (ie, MIB) have. The LSB 2 bits (B1 to B0) of the SFN may be implicitly indicated by a scrambling sequence for the PBCH (hereinafter, referred to as a “PBCH scrambling sequence”).

A gold sequence generated by being initialized with a cell ID may be used as the PBCH scrambling sequence, and the PBCH scrambling sequence may be initialized every four consecutive radio frames (ie, PBCH TTI) according to mod(SFN,4). have. A PBCH transmitted in a radio frame corresponding to an SFN in which LSB 2 bits (B1 to B0) is set to “00” may be scrambled by a Gold sequence generated by being initialized with a cell ID. Thereafter, the gold sequences generated according to mod(SFN,4) are used for scrambling the PBCH transmitted in the radio frame in which the LSB 2 bits (B1 to B0) of the SFN are “01”, “10” and “11”. can

Therefore, the UE, which has obtained the cell ID in the initial cell search process, uses the PBCH scrambling sequence in the decoding process of the PBCH (ie, the MIB) to the value of the LSB 2 bits (B1 to B0) of the SFN (e.g., "00", " 01", "10", "11") can be found implicitly. The UE uses the LSB 2 bits (B1 to B0) of the SFN identified based on the PBCH scrambling sequence and the MSB 8 bits (B9 to B2) of the SFN indicated by the PBCH (ie, MIB) to the SFN (ie, the SFN All bits (B9~B0)) can be checked.

Meanwhile, the communication system may support not only high transmission speed but also technical requirements for various service scenarios. For example, the communication system may support a high transmission rate (enhanced Mobile BroadBand; eMBB), a short transmission delay time (Ultra Reliable Low Latency Communication; URLLC), and massive machine type communication (mMTC).

A subcarrier interval of a communication system (eg, an OFDM-based communication system) may be determined based on a carrier frequency offset (CFO) or the like. The CFO may be caused by a Doppler effect, a phase drift, or the like, and may increase in proportion to an operating frequency. Accordingly, in order to prevent degradation of the communication system due to the CFO, the subcarrier spacing may increase in proportion to the operating frequency. On the other hand, as the subcarrier spacing increases, CP overhead may increase. Accordingly, the subcarrier interval may be set based on channel characteristics according to frequency bands, radio frequency (RF) characteristics, and the like.

The communication system may support numerology defined in Table 1 below.

For example, the subcarrier spacing of the communication system may be set to 15 kHz, 30 kHz, 60 kHz, or 120 kHz. The subcarrier spacing of the LTE system may be 15 kHz, and the subcarrier spacing in the NR system may be 1, 2, 4 or 8 times the existing subcarrier spacing of 15 kHz. When the subcarrier spacing is increased by an exponential multiple of 2 of the existing subcarrier spacing, the frame structure can be easily designed.

The communication system may support a wide frequency band (eg, several hundred MHz to several tens of GHz). Since the diffraction and reflection characteristics of radio waves in the high frequency band are poor, propagation loss (eg, path loss, return loss, etc.) in the high frequency band may be larger than the propagation loss in the low frequency band. Accordingly, the cell coverage of the communication system supporting the high frequency band may be smaller than the cell coverage of the communication system supporting the low frequency band. In order to solve this problem, a beamforming method based on a plurality of antenna elements may be used to increase cell coverage in a communication system supporting a high frequency band.

The beamforming method may include a digital beamforming method, an analog beamforming method, a hybrid beamforming method, and the like. In a communication system using a digital beamforming method, a beamforming gain may be obtained using a plurality of RF paths based on a digital precoder or a codebook. In a communication system using an analog beamforming method, a beamforming gain may be obtained through an analog RF device (eg, a phase shifter, a power amplifier (PA), a variable gain amplifier (VGA), etc.) and an antenna array. can

Since expensive digital to analog converter (DAC) or analog to digital converter (ADC) and transceiver units corresponding to the number of antenna elements are required for the digital beamforming method, an antenna for increasing the beamforming gain Implementation complexity may be increased. In a communication system using an analog beamforming method, since a plurality of antenna elements are connected to one transceiver unit through a phase shifter, even when a beamforming gain is increased, the complexity of antenna implementation may not significantly increase. However, the beamforming performance of the communication system using the analog beamforming method may be lower than the beamforming performance of the communication system using the digital beamforming method. In addition, since the phase shifter is adjusted in the time domain in a communication system using the analog beamforming method, frequency resources may not be efficiently used. Therefore, a hybrid beamforming method that is a combination of a digital method and an analog method may be used.

When cell coverage is increased by using the beamforming method, a common control channel and a common signal (eg, a reference signal, a synchronization signal) for all terminals belonging to the cell coverage as well as a control channel and data channel of each terminal may also be transmitted based on a beamforming method. In this case, a common control channel and a common signal for all terminals belonging to cell coverage may be transmitted based on a beam sweeping scheme.

Also, in the NR system, a synchronization block/physical broadcast channel (SS/PBCH) block may be transmitted in a beam sweeping scheme. The SS/PBCH block may be configured with PSS, SSS, PBCH, and the like, and the PSS, SSS, and PBCH within the SS/PBCH block may be configured with a time division multiplexing (TDM) scheme. The SS/PBCH block may be referred to as an “SS/PBCH block”. One SS/PBCH block may be transmitted using N consecutive OFDM symbols. Here, N may be an integer of 4 or more. The base station may periodically transmit the SS/PBCH block, and the terminal may acquire frequency/time synchronization, cell ID, system information, and the like, based on the SS/PBCH block received from the base station. The SS/PBCH block may be transmitted as follows.

5 is a conceptual diagram illustrating a first embodiment of a method for transmitting an SS/PBCH block in a communication system.

Referring to FIG. 5 , one or more SS/PBCH blocks in an SS/PBCH block burst set may be transmitted in a beam sweeping scheme. A maximum of L SS/PBCH blocks may be transmitted in one SS/PBCH block burst set. L may be an integer of 2 or more, and may be defined in the 3GPP standard. L may vary according to the region of the system frequency. In the SS/PBCH block burst set, SS/PBCH blocks may be located contiguously or distributedly. Contiguous SS/PBCH blocks may be referred to as “SS/PBCH block bursts”. The SS/PBCH block burst set may be periodically repeated, and system information (eg, MIB) transmitted through the PBCH of SS/PBCH blocks within the SS/PBCH block burst set may be the same. SS/PBCH block index, SS/PBCH block burst index, OFDM symbol index, slot index, etc. may be explicitly or implicitly indicated by the PBCH.

6 is a conceptual diagram illustrating a first embodiment of an SS/PBCH block in a communication system.

Referring to FIG. 6 , the arrangement order in the SS/PBCH block may be “PSS → PBCH → SSS → PBCH”. In the SS/PBCH block, PSS, SSS, and PBCH may be configured in a TDM manner. In the symbol in which the SSS is located, the PBCH may be disposed in frequency resources higher than the SSS and frequency resources lower than the SSS. When the maximum number of SS/PBCH blocks is 8 in a frequency band of 6 GHz or less, the index of the SS/PBCH block is based on a demodulation reference signal (DMRS) used for demodulation of the PBCH (hereinafter referred to as "PBCH DMRS"). can be confirmed as When the maximum number of SS/PBCH blocks is 64 in a frequency band of 6 GHz or higher, 3 LSB bits among 6 bits indicating the index of the SS/PBCH block may be identified based on the PBCH DMRS, and the remaining 3 MSB bits are the PBCH pay It can be identified based on the load.

The maximum system bandwidth supportable in the NR system may be 400 MHz. The size of the maximum bandwidth supportable by the terminal may vary according to the capability of the terminal. Accordingly, the UE may perform an initial access procedure (eg, an initial connection procedure) using some of the system bandwidths of the NR system supporting broadband. In order to support the access procedure of terminals supporting various sizes of bandwidth, the SS/PBCH block may be multiplexed on the frequency axis within the system bandwidth of the NR system supporting wideband. In this case, the SS/PBCH block may be transmitted as follows.

7 is a conceptual diagram illustrating a second embodiment of a method for transmitting an SS/PBCH block in a communication system.

Referring to FIG. 7 , a broadband component carrier (CC) may include a plurality of bandwidth parts (BWP). For example, a wideband CC may include 4 BWPs. The base station may transmit the SS/PBCH block in each of BWP #0 to 3 belonging to the broadband CC. The UE may receive an SS/PBCH block in one or more BWPs of BWP #0 to 3, and may perform an initial access procedure using the received SS/PBCH block.

After detecting the SS/PBCH block, the UE may acquire system information (eg, remaining minimum system information (RMSI)) and may perform a cell access procedure based on the system information. The RMSI may be transmitted through the PDSCH scheduled by the PDCCH. Configuration information of a control resource set (CORESET) in which a PDCCH including scheduling information of a PDSCH in which RMSI is transmitted is transmitted may be transmitted through a PBCH in an SS/PBCH block. A plurality of SS/PBCH blocks may be transmitted in the entire system band, and one or more SS/PBCH blocks among the plurality of SS/PBCH blocks may be an SS/PBCH block associated with an RMSI. The remaining SS/PBCH blocks may not be associated with RMSI. The SS/PBCH block associated with the RMSI may be defined as a "cell defining SS/PBCH block". The UE may perform a cell search procedure and an initial access procedure using a cell-defined SS/PBCH block. The SS/PBCH block not associated with the RMSI may be used for a synchronization procedure and/or a measurement procedure in the corresponding BWP. The BWP through which the SS/PBCH block is transmitted may be limited to one or more BWPs within a wide bandwidth.

RMSI is "Acquiring CORESET configuration information from SS/PBCH block (eg, PBCH) → PDCCH detection based on CORESET configuration information → PDSCH scheduling information acquisition from PDCCH → RMSI through PDSCH may be obtained by performing an "operation of receiving The transmission resource of the PDCCH may be configured by CORESET configuration information. The RMSI CORESET mapping pattern may be defined as follows. The RMSI CORESET may be a CORESET used for RMSI transmission/reception.

8A is a conceptual diagram illustrating RMSI CORESET mapping pattern #1 in a communication system, FIG. 8B is a conceptual diagram illustrating RMSI CORESET mapping pattern #2 in a communication system, and FIG. 8C illustrates RMSI CORESET mapping pattern #3 in a communication system It is a conceptual diagram.

8A to 8C , one RMSI CORESET mapping pattern among RMSI CORESET mapping patterns #1-3 may be used, and detailed setting according to one RMSI CORESET mapping pattern may be completed. In the RMSI CORESET mapping pattern #1, the SS/PBCH block, CORESET (eg, RMSI CORESET), and PDSCH (eg, RMSI PDSCH) may be configured in a TDM manner. The RMSI PDSCH may mean a PDSCH through which RMSI is transmitted. In RMSI CORESET mapping pattern #2, CORESET (eg, RMSI CORESET) and PDSCH (eg, RMSI PDSCH) may be configured in a TDM manner, and PDSCH (eg, RMSI PDSCH) is an SS/PBCH block and frequency division multiplexing (FDM). In RMSI CORESET mapping pattern #3, CORESET (eg, RMSI CORESET) and PDSCH (eg, RMSI PDSCH) may be set in a TDM manner, and CORESET (eg, RMSI CORESET) and PDSCH (eg, RMSI CORESET) For example, RMSI PDSCH) may be configured in an SS/PBCH block and FDM scheme.

Only RMSI CORESET mapping pattern #1 can be used in a frequency band of 6 GHz or less. All of the RMSI CORESET mapping patterns #1, #2, and #3 may be used in the frequency band above 6 GHz. The numerology of the SS/PBCH block may be different from that of "RMSI CORESET and RMSI PDSCH". Here, the neuronology may be a subcarrier spacing. In the RMSI CORESET mapping pattern #1, a combination of all neumonologies can be used. In RMSI CORESET mapping pattern #2, a combination of "SS/PBCH block, RMSI CORESET/PDSCH = 120 kHz, 60 kHz or 240 kHz, 120 kHz" may be used. In RMSI CORESET mapping pattern #3, a combination of "SS/PBCH block, RMSI CORESET/PDSCH = 120 kHz, 120 kHz" may be used.

One RMSI CORESET mapping pattern may be selected from among RMSI CORESET mapping patterns #1-3 according to a combination of the neumonology of the SS/PBCH block and the neumonology of the RMSI CORESET/PDSCH. The setting information of RMSI CORESET may include table A and table B. Table A shows the number of resource blocks (RBs) of RMSI CORESET, the number of symbols of RMSI CORESET, and RBs of SS/PBCH blocks (eg, start RBs or end RBs) and RBs of RMSI CORESETs (eg, start RBs). Alternatively, it may indicate an offset between the end RBs). Table B may indicate the number of search space sets per slot in each of the RMSI CORESET mapping patterns, the offset of the RMSI CORESET, and the OFDM symbol index. Table B may indicate information for setting a monitoring occasion of the RMSI PDCCH. Each of the tables A and B may include a plurality of tables. For example, Table A may include Tables 13-1 to 13-8 specified in TS 38.213, and Table B may include Tables 13-9 to Table 13-13 specified in TS 38.213. Each of Table A and Table B may have a size of 4 bits.

In the NR system, the PDSCH may be mapped to the time domain according to PDSCH mapping type A or B. PDSCH mapping types A and B may be defined as shown in Table 2 below.

Type A (ie, PDSCH mapping type A) may be slot-based transmission. When type A is used, the position of the start symbol of the PDSCH may be set to one of {0, 1, 2, 3}. When type A and normal CP are used, the number of symbols constituting the PDSCH (eg, the duration of the PDSCH) may be set to one of 3 to 14 within a symbol boundary. Type B (ie, PDSCH mapping type B) may be non-slot-based transmission. When type B is used, the position of the start symbol of the PDSCH may be set to one of 0 to 12. When type B and normal CP are used, the number of symbols constituting the PDSCH (eg, the duration of the PDSCH) may be set to one of {2, 4, 7} within a symbol boundary. The DMRS (hereinafter, referred to as "PDSCH DMRS") for demodulation of the PDSCH (eg, data) may be determined based on the PDSCH mapping type (eg, type A or type B) and ID indicating the length. The ID may be defined differently according to the PDSCH mapping type.

Meanwhile, NR-U (unlicensed) is being discussed at the NR standardization meeting. The NR-U system can increase network capacity by improving the utilization of limited frequency resources. The NR-U system may support operation in an unlicensed band (eg, unlicensed spectrum).

In the NR-U system, the UE may determine whether a signal is transmitted from the corresponding base station based on a discovery reference signal (DRS) received from the base station in the same way as in the general NR system. In the NR-U system of the SA (Stand-Alone) mode, the UE may acquire synchronization and/or system information based on the DRS. In the NR-U system, DRS may be transmitted according to the regulation of the unlicensed band (eg, transmission band, transmission power, transmission time, etc.). For example, according to an Occupied Channel Bandwidth (OCB) regulation, a signal may be configured and/or transmitted to occupy 80% of a total channel bandwidth (eg, 20 MHz).

In the NR-U system, a communication node (eg, a base station, a terminal) may perform a Listen Before Talk (LBT) before transmitting a signal and/or a channel for coexistence with other systems. The signal may be a synchronization signal or a reference signal (eg, DRS, DMRS, channel state information (CSI)-RS, phase tracking (PT)-RS, sounding reference signal (SRS)). The channel may be a downlink channel, an uplink channel, a sidelink channel, or the like. In embodiments, signal may mean “signal”, “channel”, or “signal and channel”. LBT may be an operation to check whether a signal is transmitted by another communication node. If it is determined by the LBT that there is no transmission signal (eg, when the LBT is successful), the communication node may transmit a signal in the unlicensed band. If it is determined by the LBT that the transmission signal exists (eg, when the LBT fails), the communication node may not be able to transmit a signal in the unlicensed band. The communication node may perform LBT according to various categories before transmission of a signal. The category of LBT may vary according to the type of transmission signal.

Meanwhile, NR V2X (vehicular to everything) communication technology is being discussed at the NR standardization conference. The NR V2X communication technology may be a technology that supports communication between vehicles, communication between vehicles and infrastructure, communication between vehicles and pedestrians, etc. based on a device to device (D2D) communication technology.

NR V2X communication (eg, sidelink communication) is to be performed according to three transmission schemes (eg, unicast scheme, broadcast scheme, groupcast scheme) can When the unicast method is used, a PC5-RRC connection may be established between the first terminal (eg, a transmitting terminal that transmits data) and a second terminal (eg, a receiving terminal that receives data), The PC5-RRC connection may mean a logical connection for a pair between the source ID of the first terminal and the destination ID of the second terminal. The first terminal may transmit data (eg, sidelink data) to the second terminal. When the broadcast method is used, the first terminal may transmit data to all terminals. When the groupcast method is used, the first terminal may transmit data to a group (eg, a groupcast group) including a plurality of terminals.

When the unicast method is used, the second terminal may transmit feedback information (eg, acknowledgment (ACK) or negative ACK (NACK)) on data received from the first terminal to the first terminal. In the embodiments below, the feedback information may be referred to as “HARQ-ACK”, “feedback signal”, “physical sidelink feedback channel (PSFCH) signal”, or the like. When the ACK is received from the second terminal, the first terminal may determine that data has been successfully received from the second terminal. When the NACK is received from the second terminal, the first terminal may determine that the second terminal has failed to receive data. In this case, the first terminal may transmit additional information to the second terminal based on a hybrid automatic repeat request (HARQ) method. Alternatively, the first terminal may improve the reception probability of data in the second terminal by retransmitting the same data to the second terminal.

When the broadcast method is used, a procedure for transmitting feedback information for data may not be performed. For example, the system information may be transmitted in a broadcast manner, and the terminal may not transmit feedback information on the system information to the base station. Accordingly, the base station may not know whether the system information has been successfully received from the terminal. To solve this problem, the base station may periodically broadcast system information.

When the groupcast method is used, a procedure for transmitting feedback information for data may not be performed. For example, necessary information may be periodically transmitted in a groupcast method without a procedure for transmitting feedback information. However, the target and/or number of terminals participating in the communication based on the groupcast method is limited, and data transmitted in the groupcast method is data that must be received within a preset time (eg, data sensitive to delay). In this case, a procedure for transmitting feedback information may be required even in groupcast sidelink communication. The groupcast sidelink communication may mean sidelink communication performed in a groupcast method. When the feedback information transmission procedure is performed in groupcast sidelink communication, data can be transmitted and received efficiently and stably.

In groupcast sidelink communication, two HARQ-ACK feedback schemes (ie, feedback information transmission procedure) may be supported. When "the number of receiving terminals in the sidelink group is large and service scenario 1 is supported", some receiving terminals belonging to a specific range in the sidelink group may transmit a NACK through the PSFCH when data reception fails. This scheme may be “groupcast HARQ-ACK feedback option 1”. In service scenario 1, instead of all the receiving terminals in the sidelink group, it may be allowed for some receiving terminals belonging to a specific range to receive in the best-effort manner. Service scenario 1 may be an extended sensor scenario in which some receiving terminals belonging to a specific range need to receive the same sensor information from a transmitting terminal. In embodiments, the transmitting terminal may mean a terminal transmitting data, and the receiving terminal may mean a terminal receiving data.

If "the number of receiving terminals in the sidelink group is limited and service scenario 2 is supported", each of all receiving terminals belonging to the sidelink group may individually report HARQ-ACK for data through a separate PSFCH. have. This scheme may be “groupcast HARQ-ACK feedback option 2”. In service scenario 2, since the PSFCH resource is sufficient, the transmitting terminal can monitor the HARQ-ACK feedback of all receiving terminals belonging to the sidelink group, and data reception is guaranteed by all the receiving terminals belonging to the sidelink group can be

In addition, data reliability in the receiving terminal may be improved by appropriately adjusting the power of the transmitting terminal according to the transmission environment. Interference to other terminals can be mitigated by appropriately adjusting the power of the transmitting terminal. Energy efficiency can be improved by reducing unnecessary transmit power. The power control method may be classified into an open-loop power control method and a closed-loop power control method. In the open-loop power control method, the transmitting terminal may determine the transmit power in consideration of a set and measured environment, and the like. In the closed-loop power control scheme, the transmitting terminal may determine the transmit power based on a transmit power control (TPC) command received from the receiving terminal.

Predicting the received signal strength in the receiving terminal may be difficult due to various causes including a multipath fading channel, interference, and the like. Accordingly, the reception terminal may adjust the reception power level (eg, reception power range) by performing an automatic gain control (AGC) operation in order to prevent a quantization error of the reception signal and maintain appropriate reception power. In a communication system, a terminal may perform an AGC operation using a reference signal received from a base station. However, in sidelink communication (eg, V2X communication), the reference signal may not be transmitted from the base station. That is, in sidelink communication, communication between terminals may be performed without a base station. Therefore, it may be difficult to perform an AGC operation in sidelink communication. In sidelink communication, a transmitting terminal may first transmit a signal (eg, a reference signal) to a receiving terminal before transmission of data, and the receiving terminal performs an AGC operation based on a signal received from the transmitting terminal, thereby receiving power range (eg, a received power level) may be adjusted. Thereafter, the transmitting terminal may transmit the sidelink data to the receiving terminal. The signal used for the AGC operation may be a duplicated signal for a signal to be transmitted later or a signal preset between terminals.

The time period required for the AGC operation may be 15 μs. When the subcarrier interval is 15 kHz in the NR system, the time interval (eg, length) of one symbol (eg, OFDM symbol) may be 66.7 μs. When the subcarrier interval is 30 kHz in the NR system, the time interval of one symbol (eg, OFDM symbol) may be 33.3 μs. In the embodiments below, a symbol may mean an OFDM symbol. That is, the time interval of one symbol may be twice or more than the time interval required for the AGC operation.

For sidelink communication, it may be necessary to transmit a data channel for data transmission and a control channel including scheduling information for data resource allocation. In sidelink communication, the data channel may be a Physical Sidelink Shared CHannel (PSSCH), and the control channel may be a Physical Sidelink Control CHannel (PSCCH). The data channel and the control channel may be multiplexed in a resource domain (eg, a time and frequency resource domain).

9 is a conceptual diagram illustrating embodiments of a method for multiplexing a control channel and a data channel in sidelink communication.

Referring to FIG. 9 , sidelink communication may support option 1A, option 1B, option 2, and option 3. If option 1A and/or option 1B is supported, the control channel and data channel may be multiplexed in the time domain. If option 2 is supported, the control channel and data channel can be multiplexed in the frequency domain. If option 3 is supported, the control channel and data channel can be multiplexed in time and frequency domains. Sidelink communication can support option 3 natively.

In sidelink communication (eg, NR-V2X sidelink communication), a basic unit of resource configuration may be a subchannel. A subchannel may be defined by time and frequency resources. For example, a subchannel may be composed of a plurality of symbols (eg, OFDM symbols) in the time domain and may be composed of a plurality of resource blocks (RBs) in the frequency domain. A subchannel may be referred to as an RB set. In the subchannel, the data channel and the control channel can be multiplexed based on option 3.

In sidelink communication (eg, NR-V2X sidelink communication), transmission resources may be allocated based on mode 1 or mode 2. When mode 1 is used, the base station may allocate a sidelink resource for data transmission to the transmitting terminal in a resource pool, and the transmitting terminal receives data using the sidelink resource allocated by the base station. It can be transmitted to the terminal. Here, the transmitting terminal may be a terminal transmitting data in sidelink communication, and the receiving terminal may be a terminal receiving data in sidelink communication.

When mode 2 is used, the transmitting terminal may autonomously select a sidelink resource to be used for data transmission by performing a resource sensing operation and/or a resource selection operation within the resource pool. The base station may set a resource pool for mode 1 and a resource pool for mode 2 in the terminal(s). The resource pool for mode 1 may be set independently of the resource pool for mode 2. Alternatively, a common resource pool may be configured for mode 1 and mode 2.

When mode 1 is used, the base station may schedule a resource used for sidelink data transmission to the transmitting terminal, and the transmitting terminal may transmit sidelink data to the receiving terminal using the resource scheduled by the base station. Therefore, resource collision between terminals can be prevented. When mode 2 is used, the transmitting terminal may select an arbitrary resource by performing a resource sensing operation and/or a resource selection operation, and may transmit sidelink data using the selected arbitrary resource. Since the above-described procedure is performed based on an individual resource sensing operation and/or resource selection operation of each transmitting terminal, a collision between selected resources may occur.

The sidelink communication system supporting Rel-16 may be designed for terminals (eg, vehicle-mounted terminals, vehicle UEs (V-UEs)) that do not have much restriction on battery capacity. Therefore, the power saving issue in the resource sensing/selection operation of the terminal may not be significantly considered. In a sidelink communication system supporting Rel-17, a terminal having restrictions on battery capacity (eg, a terminal carried by a pedestrian, a terminal mounted on a bicycle, a terminal mounted on a motorcycle, a pedestrian UE (P-UE)) For sidelink communication with ), power saving methods will be needed. In the present application, V-UE may mean a terminal that has no significant restrictions on battery capacity, P-UE may mean a terminal with restrictions on battery capacity, and "resource sensing/selection operation" means "resource sensing operation and/or resource selection operation". The resource sensing operation may mean a partial sensing operation or a full sensing operation. The resource selection operation may mean a random selection operation. In addition, in the present application, "operation of a terminal" may be interpreted as "operation of a V-UE" and/or "operation of a P-UE".

For power saving in LTE V2X, a partial sensing operation and/or a random selection operation may be introduced. When a partial sensing operation is supported, the terminal may perform a resource sensing operation in a partial interval instead of an entire interval within the sensing window, and may select a resource based on a result of the partial sensing operation. According to this operation, power consumption of the terminal can be reduced. When the random selection operation is supported, the UE may randomly select a resource without performing a resource sensing operation. Alternatively, the random selection operation may be performed together with the resource sensing operation. For example, the terminal may determine a resource by performing a resource sensing operation, and may select a resource(s) by performing a random selection operation within the determined resources.

In LTE V2X supporting Rel-14, a resource pool capable of performing a partial sensing operation and/or a random selection operation may be set independently of a resource pool capable of performing a complete sensing operation. A resource pool capable of performing a random selection operation, a resource pool capable of performing a partial sensing operation, and a resource pool capable of performing a complete sensing operation may be independently configured. The UE may select a resource by performing a random selection operation, a partial sensing operation, and/or a complete sensing operation from the resource pool. The terminal may select one operation from the random selection operation and the partial sensing operation, may select a resource by performing the selected operation, and may perform sidelink communication using the selected resource.

In LTE V2X supporting Rel-14, SL (sidelink) data may be periodically transmitted based on a broadcast method. In the NR communication system, SL data may be transmitted based on a broadcast method, a multicast method, a groupcast method, or a unicast method. In addition, in the NR communication system, SL data may be transmitted periodically or aperiodically. The transmitting terminal may transmit SL data to the receiving terminal, and the receiving terminal may transmit HARQ feedback (eg, ACK or NACK) for the SL data to the transmitting terminal through the PSFCH. In the present application, a transmitting terminal may mean a terminal transmitting SL data, and a receiving terminal may mean a terminal receiving SL data.

Next, methods for improving coverage of a terminal in a communication system will be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of the transmitting terminal is described, the corresponding receiving terminal may perform an operation corresponding to the operation of the transmitting terminal. Conversely, when the operation of the receiving terminal is described, the corresponding transmitting terminal may perform an operation corresponding to the operation of the receiving terminal.

A terminal having reduced capability (hereinafter, referred to as a “RedCap terminal”) may operate in a specific usage environment. Capability of RedCap terminal may be lower than the capability of NR (new radio) normal terminal, LTE-MTC (machine type communication) terminal, NB (narrow band)-IoT (internet of things) terminal, And it may be higher than the capability of each of the LPWA (Low Power Wide Area) terminal. For example, terminals (eg, surveillance cameras) that require "high data rate and non-high latency conditions" and/or "non-high data rates, high latency conditions, and high reliability ( A terminal (eg, a wearable device) that requires "reliability" may exist. In order to support the above-described terminals, the maximum carrier bandwidth in FR1 may be reduced from 100 MHz to 20 MHz, and the maximum carrier bandwidth in FR2 may be reduced from 400 MHz to 100 MHz. The number of receive antennas of the redcap terminal may be smaller than the number of receive antennas of the NR normal terminal. When the carrier bandwidth and the number of reception antennas are reduced, reception performance in the RedCap terminal may decrease, and accordingly, the coverage of the RedCap terminal may decrease. In the present application, various methods for improving the coverage of a RedCap terminal will be proposed. A RedCap terminal may mean a RedCap UE, and an NR general terminal may mean a general terminal or a general UE.

Due to the reduction in complexity of the RedCap terminal and/or the reduction in the number of receive antennas, the coverage of the ReCap terminal may decrease. In order to improve coverage, an aggregation level may be increased to lower a code rate in a PDCCH transmission procedure. The above-described operation may not be suitable because the number of control channel elements (CCEs) available in the small bandwidth in which the RedCap terminal operates is not sufficient. The minimum code rate of the polar code used for the NR PDCCH may be 1/8, and the effect when a code rate lower than the minimum code rate is applied may be the same as the effect of a simple repetition code. have. For example, "when the size of a downlink control channel (DCI) payload is about 40 bits and greater than an aggregation level (AL) 4", the polar code may operate in the same way as the repetition code. Accordingly, coverage (eg, PDCCH transmission coverage) may be improved through PDCCH repetitions instead of increasing AL in a limited control resource set (CORESET). The PDSCH scheduled by the PDCCH may be transmitted within a plurality of slots through all slots or slot aggregation, unlike the PDCCH transmitted within a limited CORESET. Resources available for PDSCH transmission may have more room than resources available for PDCCH transmission. Accordingly, a method for improving coverage by repeatedly transmitting a PDCCH scheduling a PDSCH or a group common PDCCH may be proposed. The PDCCH repeated transmission method includes "a method of repeatedly transmitting a PDCCH in one slot (hereinafter referred to as a "one-slot repeated transmission method")" and a "method of repeatedly transmitting a PDCCH in a plurality of slots (hereinafter referred to as a "one-slot repeated transmission method"). , "multi-slot repeated transmission method")" may be included. The PDCCH repeated transmission method may be configured by system information and/or RRC signaling (eg, UE-specific RRC signaling).

The PDCCH repeated transmission method may be performed differently according to the type of PDCCH. In order to support the method of repeatedly transmitting the PDCCH in one slot (that is, the one-slot repeated transmission method), monitoring occasions of a plurality of search space sets in the slot are to be set. and the base station may transmit a plurality of PDCCHs in monitoring occasions. The UE may detect a plurality of PDCCHs by performing a PDCCH monitoring operation in monitoring occasions, and may obtain a coverage improvement effect through the plurality of PDCCHs. Alternatively, a plurality of CORESETs for PDCCH transmission may be configured, a search space set(s) associated with the plurality of CORESETs may be configured within a slot, and the base station may set a search space associated with the plurality of CORESETs. A plurality of PDCCHs may be transmitted in the set(s). The UE may detect a plurality of PDCCHs by performing a PDCCH monitoring operation in the search space set(s) associated with the plurality of CORESETs, and may obtain a coverage improvement effect through the plurality of PDCCHs.

In order to support a method of repeatedly transmitting the PDCCH in a plurality of slots (ie, a multi-slot repeated transmission method), monitoring occasions of search space sets in a plurality of slots may be configured, and the base station may set the monitoring occasion may transmit a plurality of PDCCHs. The UE may detect a plurality of PDCCHs by performing a PDCCH monitoring operation in monitoring occasions, and may obtain a coverage improvement effect through the plurality of PDCCHs. Alternatively, a plurality of CORESETs for PDCCH transmission may be configured, a search space set(s) associated with the plurality of CORESETs may be configured within a plurality of slots, and the base station may be associated with a plurality of CORESETs A plurality of PDCCHs may be transmitted in the search space set(s). The UE may detect a plurality of PDCCHs by performing a PDCCH monitoring operation in the search space set(s) associated with the plurality of CORESETs, and may obtain a coverage improvement effect through the plurality of PDCCHs.

Since the UE-specific PDCCH can be transmitted through common search space (CSS) and/or UE-specific search space (USS), both the one-slot repeated transmission method and the multi-slot repeated transmission method are based on the transmission procedure of the UE-specific PDCCH. can be applied. In an embodiment, the CSS (or CSS set) may be set in the front region or an arbitrary region within the slot, and the USS (or USS set) may be set in the front region or any region within the slot. For example, CSS may be set in a front region within a slot, and USS may be set in an arbitrary region within a slot. Alternatively, the CSS may be set in an arbitrary area within the slot, and the USS may be set in the front area within the slot. The aforementioned front region may include “the first symbol in the slot”, “the first symbol and the second symbol in the slot”, or “the first symbol, the second symbol, and the third symbol in the slot”.

Operations based on CSS (or CSS set) set in the front region within the slot may be applied to CSS (or CSS set) set in an arbitrary region within the slot. Conversely, operations based on CSS set in an arbitrary area within a slot may be applied to CSS set at a front area within a slot. Also, operations based on the USS (or USS set) set in the front area within the slot may be applied to the USS (or USS set) set at any area within the slot. Conversely, operations based on the USS set in an arbitrary area within the slot may be applied to the USS set at the front area within the slot.

When the CSS is set in three symbols (eg, the front region) from the first symbol in the slot, it is preferable to apply the multi-slot repeated transmission method for the common PDCCH transmitted only through the CSS. In order to repeatedly transmit a common PDCCH in a slot, a CORESET composed of one symbol may be configured, and a monitoring opportunity of CSS associated with the corresponding CORESET may be configured in three symbols from the first symbol in the slot. . That is, when the above-described configuration is supported, the one-slot repeated transmission method may be applied to the transmission procedure of the common PDCCH. Alternatively, a CORESET composed of two symbols may be set, and the CORESETs may be set to overlap each other. Alternatively, it may be allowed to set the monitoring occasion for CSS in the entire region rather than the front region of the slot, and in this case, the one-slot repeated transmission method may be applied to the transmission procedure of the common PDCCH.

In order to obtain improved performance through repeated transmission of PDCCHs, a soft-combining operation between repeated PDCCHs may be configured to be easily performed. In order to support this operation, the mapping position of the next PDCCHs, the scrambling sequence, and/or the demodulation-reference signal (DM-RS) mapping method based on the first PDCCH among the repeated PDCCHs remains the same. can be Alternatively, the mapping position of the next PDCCHs, the scrambling sequence, and/or the DM-RS mapping method can be easily derived based on the first PDCCH among the repeated PDCCHs. Based on the first PDCCH among the repeated N PDCCHs, the following PDCCHs may be mapped to the same CCE in each PDCCH resource region. Alternatively, based on the first PDCCH among the N repeated PDCCHs, the following PDCCHs may be mapped to the CCE according to a specific criterion in consideration of the number of repeated transmissions. For example, in the CCE mapping procedure of the PDCCH, a value obtained by multiplying the number of repeated transmissions of the PDCCH by a specific offset may be added. Specifically, since the location of the CCE for CSS (eg, a fixed location) may be determined according to the AL, the same CCE location according to the same AL for each PDCCH resource region may be secured. The CCE mapping position of the USS in one CORESET may be determined by a function of a cell-radio network temporary identifier (C-RNTI) and a slot index. Therefore, when a plurality of PDCCHs are repeatedly transmitted in one slot, the same CCE position can be secured for each PDCCH resource region because the slot index does not change.

When a plurality of PDCCHs are repeatedly transmitted in a plurality of slots, a position of a candidate CCE for PDCCH transmission in the same CORESET may vary according to a change in a slot index. In order to prevent the location of the candidate CCE from being changed, the CCE mapping location of the USS may be determined in the same way as the CSS instead of a function of the C-RNTI and slot. Alternatively, the USS may be mapped to the CCE according to a separate formula. In this case, the USS (eg, the USS for the next PDCCH of the first PDCCH) may be mapped to the CCE according to a specific criterion based on the first PDCCH. Here, the CCE mapping position of the first PDCCH may be determined by a function of the C-RNTI and the slot index based on the existing scheme.

In order to easily perform a soft combining operation between repeated PDCCHs, a scrambling sequence may be equally applied. Each of n _ID and n _RNTI for initialization of a scrambling sequence for CSS may be set to a cell ID and 0. n _ID and n _RNTI for initialization of a scrambling sequence for USS may be identically set by higher layer parameters. Alternatively, n _ID and n _RNTI for initialization of a scrambling sequence for USS may not be set by higher layer parameters. According to the above-described setting, USS can be applied in the same way as CSS. When a non-interleaved scheme is used in a CCE-to-REG (resource element group) mapping procedure, a soft combining operation between PDDCHs can be easily performed. If the soft combining operation is applicable to the repeated PDCCHs, the remaining PDCCH(s) except for the first PDCCH among the repeated PDCCHs may not be included in the number of times blind decoding is performed in the slot.

When PDCCHs are repeatedly transmitted, it is preferable that DM-RS mapping between PDCCH resource regions remains the same. When the DM-RS mapping between PDCCH resource regions is maintained the same, joint channel estimation is performed by using DM-RSs in the PDCCH resource regions together regardless of the one-slot repeated transmission method and the multi-slot repeated transmission method operation may be performed, and channel estimation performance may be improved by the joint channel estimation operation. Accordingly, PDCCH reception performance may be improved. If the mapping positions of the actual PDCCHs repeatedly transmitted between PDCCH resource regions are not maintained the same, setting the precoding granularity of the DM-RS to wideband (allContiguousRBs) to facilitate the joint channel estimation operation is desirable. In order to perform a joint channel estimation operation, a transmission beam and precoding between PDCCH resource regions may be equally applied. Accordingly, the base station may maintain the same configuration of the transmission beam and precoding in the PDCCH resource regions to enable the joint channel estimation operation, and may signal the configuration to the terminal using a specific indication. In this case, the specific indication may be transmitted using at least one of cell-specific RRC signaling, UE-specific RRC signaling, or DCI.

When PDCCHs are repeatedly transmitted, it is preferable to limit the ALs available for each PDCCH transmission. Considering the number of repeated PDCCH transmissions, usable ALs may be limited so that the number of CCEs used for repeated PDCCHs is greater than the maximum number of CCEs usable for one PDCCH transmission. For example, "transmitting the PDCCH 4 times using AL 4" is "using 16 CCEs", and there is a difference between the performance of this operation and the performance of the operation of transmitting the PDCCH 1 time using AL 16. There may be no difference. Therefore, it is preferable to use an AL larger than AL 4 in each PDCCH transmission procedure. When the maximum number of CCEs usable for one PDCCH transmission is max _CCE , the AL used in the procedure for repeatedly transmitting the PDCCH N times may be ceil(max _CCE /N) or more.

When the PDCCH is repeatedly transmitted to improve the coverage of the PDCCH, improved performance can be secured by guaranteeing the number of repeated PDCCH transmissions. When the one-slot repeated transmission method or the multi-slot repeated transmission method is used, some PDCCHs may not be transmitted according to the slot format. For example, when the number of downlink symbols and/or flexible symbols capable of transmitting a PDCCH in the one-slot repeated transmission method or the multi-slot repeated transmission method is insufficient, some PDCCHs may not be transmitted. In this case, transmission of the corresponding PDCCH may be abandoned, and the base station may repeatedly transmit the remaining PDCCHs. For example, if it is difficult to transmit a PDCCH in M PDCCH transmission regions among PDCCH transmission regions configured for N repeated transmission of the PDCCH, the base station may give up PDCCH transmission in the M PDCCH transmission regions. That is, the base station may repeatedly transmit the PDCCH (N-M) times. Each of N and M may be a natural number. When the PDCCH is not transmitted by the preset number of repeated PDCCH transmissions (ie, N), the transmission coverage of the PDCCH may be reduced. In the present application, when N repeated transmission of the PDCCH is configured, methods for guaranteeing N repeated transmission may be proposed.

When the PDCCH is repeatedly transmitted N times, the number of repeated transmissions of the corresponding PDCCH may be checked based on the DM-RS sequence of each PDCCH, and N repeated transmissions of the PDCCH may be guaranteed based on the identification result. Specifically, in the PDCCH DM-RS sequence initialization procedure, an index according to the number of repeated PDCCH transmissions may be additionally considered. The PDCCH DM-RS may be generated differently according to the number of repeated transmissions. By detecting the PDCCH DM-RS, the UE may check the number of repeated transmissions of the PDCCH transmission related to the PDCCH DM-RS, and the reception coverage of the PDCCH may be improved by the repeated PDCCHs. It is desirable to indicate that the repeated PDCCHs are the same PDCCH. It is desirable to facilitate detection of the PDCCH in the PDCCH resource region. Accordingly, the mapping position of the PDCCH in the PDCCH resource region may be fixed based on the first PDCCH. Alternatively, the PDCCH may be mapped in the PDCCH resource region according to a preset criterion. In order to guarantee the detection performance of the number of repeated transmissions, the length of the PDCCH DM-RS sequence may be set sufficiently long. For example, it is preferable to set the precoding granularity of the PDCCH DM-RS to wideband (allContiguousRBs). The above-described embodiment may be equally or similarly applied not only to the PDCCH but also to the PUCCH. In this case, the PUCCH DM-RS sequence initialization operation may be performed the same or similar to the above-described PDCCH DM-RS sequence initialization operation.

As another method for confirming the number of repeated transmissions of the PDCCH, PDCCH contents may include an index indicating the number of repeated transmissions of the corresponding PDCCH. When N repeated transmission of the PDCCH is configured, a ceil(log2(N)) bit may be added to the PDCCH to indicate the number of repeated transmissions of the PDCCH. The ceil(log2(N)) bit included in the PDCCH may indicate the number of repeated transmissions among N repeated transmissions. In order to easily perform the soft combining operation of the repeated PDCCHs, it is preferable not to apply scrambling to a bit indicating information (eg, index) indicating the number of repeated PDCCH transmissions.

Until additional PDSCH time domain resource configuration is received through RRC signaling, a PDCCH scheduling system information transmitted through CSS and/or a group common PDCCH may include a default PDSCH time domain resource configuration. In the default PDSCH time domain resource configuration, the slot offset (K ₀ ) between the PDCCH and the PDSCH scheduled by the PDCCH may be set to 0 except for some non-slot-based scheduling. When the one-slot repeated transmission method is used, the resources for PDSCH transmission may not be sufficient in consideration of resources for PDCCH repeated transmission within one slot. Therefore, in the default PDSCH time axis resource configuration, K ₀ may be set to a value greater than 0 even when non-slot-based scheduling is not performed.

When the multi-slot repeated transmission method is used, it is preferable that the UE interprets the scheduling information based on the last PDCCH. When the slot offset (K ₀ ) between the PDCCH and the PDSCH is applied, the UE may receive the PDSCH by applying K ₀ based on the last PDCCH. Therefore, a method for determining the last PDCCH among the repeated PDCCHs is needed. The UE may identify the last PDCCH from among the repeated PDCCHs based on information indicating the number of repeated PDCCH transmissions. Alternatively, the last PDCCH among the repeated PDCCHs may be indicated through separate signaling, and the UE may check the last PDCCH based on the separate signaling. For example, an indication indicating the last PDCCH may be added to the PDCCH DM-RS sequence initialization for the last PDCCH. In this case, the last PDCCH may be distinguished from other PDCCHs.

In a communication system in which a normal terminal and a RedCap terminal coexist, "when the PDSCH is scheduled based on the last PDCCH among the repeated PDCCHs and an additional indication for detecting the last PDCCH is applied", the general terminal uses the corresponding PDCCH (e.g. , the last PDCCH) may not be detected. Therefore, when the PDCCH is repeatedly transmitted N times, it is preferable to add an indication for the RedCap UE to the first PDCCH. The RedCap UE may detect the first PDCCH from among the N repeated PDCCHs based on the above-mentioned indication, and then may acquire control information through the N-1 repeated PDCCHs. Since the last PDCCH can be received by both the general terminal and the RedCap terminal, the general terminal can detect only the last PDCCH and obtain control information through the last PDCCH.

Alternatively, an indication indicating the number of PDCCHs among the N repeated PDCCHs may exist separately. In this case, the last PDCCH may have a PDCCH form of a normal UE, and (N-1) PDCCHs before the last PDCCH may include an indication indicating the number of repeated transmissions of the corresponding PDCCH.

Specifically, when the number of repeated transmissions of the PDCCH is indicated by the PDCCH DM-RS sequence initialization, an index indicating the number of repeated transmissions (ie, n _idx ) may be added to c _init , which is the equation of the PDCCH DM-RS sequence initialization. have. That is, c _init +n _idx may be generated. The value of n _idx according to the number of repeated transmissions of the PDCCH may be set as shown in Table 3 below. That is, the value of n _idx may be set opposite to the number of repeated transmissions of the PDCCH.

In this case, the first PDCCH may be detected using “n _idx = N-1” and the last PDCCH may be detected using “n _idx = 0”. In the case of "n _idx = 0", since the equations of PDCCH DM-RS sequence initialization are the same in the normal UE and the RedCap UE, both the normal UE and the RedCap UE may receive the last PDCCH. The RedCap UE may check the last PDCCH based on the PDCCH DM-RS. The number of repeated transmissions of the PDCCH may be indicated by reserved bits of the corresponding PDCCH. The normal UE may ignore the reserved bits of the PDCCH, and the RedCap UE may check the number of repeated transmissions of the corresponding PDCCH based on the reserved bits of the PDCCH.

As another method for improving the PDCCH coverage problem of the RedCap UE, a method of transmitting the PDSCH without a PDCCH may be proposed. A method of transmitting a PDSCH without a PDCCH containing various control information including scheduling information may be suitable for transmitting various system information including a periodically transmitted system information block (SIB)1. When the RedCap terminal and the general terminal perform a common initial access procedure, since a separate system information transmission procedure is not required, the efficiency of resource use can be improved. When the number of RedCap terminals is large, it may be efficient to perform a separate initial access procedure for the RedCap terminals. When a separate initial access procedure distinct from the initial access procedure for the existing UE is performed, a method in which scheduling information for SIB1 is transmitted through the PBCH may be proposed. In this case, the scheduling information included in the PBCH may be information (eg, resource configuration information and/or modulation and coding scheme (MCS)) included in DCI format 1_0. Alternatively, the scheduling information included in the PBCH may include an index of a specific candidate list among candidate lists for preset scheduling information.

As a method of transmitting system information (SI) message(s) without a PDCCH, a method of including scheduling information for the SI message(s) in SIB1 may be proposed. SIB1 may include at least one of information included in each SI message, an SI-window length through which the SI message is transmitted, or a transmission period of the SI message. In addition, SIB1 may further include specific scheduling information (eg, resource configuration information and/or MCS) for each SI message. In this case, the scheduling information included in SIB1 may be information (eg, resource configuration information and/or MCS) included in DCI format 1_0. Alternatively, the scheduling information included in SIB1 may include an index of a specific candidate list among candidate lists for preset scheduling information.

인 경우", SI 메시지 X의 전송을 위해 필요한 RB 개수(

)는 아래 수학식 1에 기초하여 결정될 수 있다.As another method of transmitting SI message(s) without PDCCH, the MCS applied to the SI message(s) may be set to be the same as the MCS applied to SIB1, and the transmission resource of the SI message(s) is the transmission resource of SIB1 can be set to be proportional to . The time domain resource of the SI message(s) may be maintained the same as the time domain resource of SIB1, and the frequency domain resource of the SI message(s) may be adjusted based on the frequency domain resource of SBI1. The frequency domain resource of the SI message may be adjusted in proportion to the payload size of the SI message based on the frequency domain resource of SIB1. For example, "The payload size of SIB1 is SIB1 _size , the number of RBs for transmitting SIB1 is SIB1 _RB , and the payload size of SI message X is

If ", the number of RBs required for transmission of SI message X (

) may be determined based on Equation 1 below.

The start position of the frequency domain resource of the SI message may be set to be the same as the start position of the frequency domain resource of SIB1, and the size of the frequency domain resource of the SI message may be adjusted based on the start position. The size of the frequency domain resource of the SI message may be simultaneously adjusted to both sides around the frequency position of SIB1. For accurate calculation, payload size information of each SI message may be included in SIB1. Even when it is assumed that the time domain resources of the SI message and SIB1 are the same, the slot in which the SIB1 is transmitted may be different from the slot in which the SI message X is transmitted according to the actual slot format setting.

Therefore, a method of adding or subtracting the frequency domain resource of the SI message X by delta _RB by considering that the slot in which the SIB1 is transmitted and the slot in which the SI message X is transmitted are different according to the slot format setting may be proposed. For example, "when the time domain resource of SIB1 is 14 symbols and the time domain resource of SI message X is 12 symbols", one or more RBs corresponding to the reduced number of symbols (eg, 2) are SI messages It may be added to the frequency domain resource of X. For another example, "when the time domain resource of SIB1 is 12 symbols and the time domain resource of SI message X is 14 symbols", one or more RBs corresponding to the increased number of symbols (eg, 2) are SI It may be excluded from the frequency domain resource of message X. The above-described method may be defined as in Equation 2 below.

)는 아래 수학식 3에 기초하여 결정될 수 있다.Alternatively, one RB (eg, 12 subcarriers) in the frequency domain and one symbol in the time domain may be defined as one resource unit. The number of resource units occupied by the PDSCH transmitting SIB1 is SIB1 _RU , and the number of resource units occupied by the PDSCH transmitting the SI message X (

) may be determined based on Equation 3 below.

인 경우, 주파수 도메인에서 SI 메시지 X를 위한 RB 크기(

)는 아래 수학식 4에 기초하여 결정될 수 있다.The number of available symbols in the slot in which the SI message X is transmitted is

, RB size for SI message X in the frequency domain (

) may be determined based on Equation 4 below.

The size of time and frequency domain resources of PDSCH for transmission of SI message X is "Ratio of payload size of SIB1 to payload size of SI message X" and "Size of time and frequency domain resources of PDSCH for SIB1 transmission" may be set based on Accordingly, the UE may receive the corresponding SI message(s) without receiving the PDCCH scheduling the SI message(s). When the system bandwidth for the RedCap terminal is not large, the size adjustment of the frequency domain resource for the SI message(s) may be limited. In this case, the size of the frequency domain resource of the SI message(s) may be fixed, and the time domain resource of the SI message(s) may be set in consideration of the ratio of the payload size according to the above-described method. When the time domain resource required for transmission of the SI message(s) exceeds one slot, the PDSCH including the SI message(s) may be transmitted in a plurality of slots. That is, multi-slot scheduling may be configured for SI message(s). The resource setting method in consideration of the ratio of the payload size between SI messages may be simultaneously applied for setting the time and frequency domain resource size.

The RedCap terminal may perform the same initial access procedure as a general terminal. In this case, the resource setting information may be fixed in advance. Alternatively, the RedCap terminal and the general terminal may receive SIB1 in the same way, and the RedCap terminal may receive SI message(s) based on information included in SIB1 according to the above-described method. In this case, although the general terminal receives scheduling information of the SI message(s) through the PDCCH, the general terminal may receive the SI message(s) scheduled by the predefined method in the same way as the RedCap terminal. Accordingly, scheduling efficiency may be degraded.

Scheduling of system information (eg, SI message(s)) for a general terminal and scheduling of system information for a RedCap terminal may be performed independently. In this case, since the scheduling DCI for system information for each of the general terminal and the RedCap terminal is transmitted, the transmission overhead of the scheduling DCI may increase. In order to solve the above-described problem, a method in which one DCI schedules both system information for a general terminal and system information for a RedCap terminal will be proposed when separate system information for a RedCap terminal is transmitted. Here, DCI may be basically used for scheduling of system information for a general terminal, and scheduling information of system information for a RedCap terminal may be added to the DCI. In an embodiment, scheduling information for a normal terminal may be referred to as "normal scheduling information", and scheduling information for a RedCap terminal may be referred to as "RedCap scheduling information".

Specifically, DCI format 1_0 may schedule general system information and may be scrambled by SI-RNTI. Reserved bits (eg, 15 bits) of DCI format 1_0 may be set as scheduling information of RedCap system information. The number of reserved bits for RedCap system information may be smaller than the number of bits required for scheduling of general system information. Therefore, the scheduling information of the RedCap system information may be set in consideration of the number of reserved bits. In the present application, a method for scheduling RedCap system information using reserved bits of DCI for scheduling general system information will be proposed.

Since the number of reserved bits included in DCI is not sufficient, one or more information elements in the scheduling information of the RedCap system information may be indicated by a relative offset with respect to the scheduling information of the general system information. Among the scheduling information of the general system information, time domain resource allocation information (eg, time domain scheduling information) and VRB-to-PRB mapping information may be used as scheduling information of the RedCap system information. In this case, time domain resource allocation information and VRB-to-PRB mapping information for scheduling of RedCap system information may not be separately signaled. Scheduling information of general system information may be used as redundancy information for a RedCap terminal. In this case, redundancy information for the RedCap terminal may not be separately signaled. Alternatively, in order to improve scheduling flexibility, redundancy information for a RedCap terminal may be separately signaled.

Scheduling information of general system information may be used as a system information indicator of the RedCap terminal. In this case, the system information indicator of the RedCap terminal may not be separately signaled. In order to improve the flexibility of scheduling and resource use, a separate system information indicator for the RedCap terminal may be used. The size of the corresponding system information indicator may be 1 bit.

Frequency domain resource allocation information for scheduling of RedCap system information may be indicated in the same manner as frequency domain resource allocation information for scheduling of general system information. When the number of reserved bits in DCI is not sufficient, a simple signaling method may be used to indicate frequency domain resource allocation information for scheduling of RedCap system information. A frequency domain resource for transmission of RedCap system information may be allocated to be adjacent to a frequency domain resource for transmission of general system information. In this case, the frequency domain resource allocation information for scheduling of the RedCap system information may include the first information and the second information. The first information may indicate a location of a frequency domain resource for transmission of RedCap system information based on a frequency domain resource for transmission of general system information. The size of the first information may be 1 bit, and the first information set to a first value (eg, 0) has a frequency domain resource for transmission of RedCap system information below a frequency domain resource for transmission of general system information. may indicate that it is located in , and the first information set to a second value (eg, 1) indicates that a frequency domain resource for transmission of RedCap system information is located on a frequency domain resource for transmission of general system information. can The second information may indicate the size (eg, the number of RBs) of a frequency domain resource for transmission of RedCap system information.

The number of bits required when scheduling frequency domain resources for transmission of RedCap system information based on the above-described method is the number of bits required when scheduling frequency domain resources for transmission of RedCap system information based on the existing method. may be smaller than For example, when the size of the frequency domain resource allocated for the transmission of RedCap system information is 96 RB, 13 bits may be required to schedule the frequency domain resource for the RedCap terminal using the existing method, and the method ( For example, 8 bits may be required to schedule a frequency domain resource for a RedCap terminal using a combination of the first information and the second information). Among 8 bits, 1 bit may indicate the location of frequency domain resources, and ratio 7 of 8 bits may indicate the size (eg, number of RBs) of frequency domain resources. A frequency domain resource having a maximum of 128 RBs using 8 bits may be indicated. In this case, when the minimum number of RBs is set to a value greater than 0, the number of bits required for scheduling a frequency domain resource for a RedCap terminal may be reduced.

MCS information for transmission of general system information may be used as MCS information for transmission of RedCap system information. Alternatively, MCS information for transmission of RedCap system information may be separately signaled in consideration of characteristics of RedCap system information. In order to reduce the number of bits required to indicate MCS information, MCS information for transmission of RedCap system information may be expressed as an offset to MCS information for transmission of general system information (hereinafter referred to as "MCS offset"). have. The RedCap terminal may determine MCS information for transmission of RedCap system information by applying an MCS offset to MCS information for transmission of general system information. When the MCS offset is applied, the MCS level (eg, MCS index) for transmission of RedCap system information may be set as shown in Table 4 below. That is, the MCS offset may be set to 0, -offset, or +offset.

The MCS offset may be set in reserved bit(s) of DCI. In order to reduce the number of bits required for signaling of the MCS offset, an application range of the MCS offset may be limited. Specifically, the complexity of the RedCap terminal may be lower than that of the general terminal, and the reception coverage of the RedCap terminal may be shorter than the reception coverage of the general terminal. To solve this problem, the MCS level for the RedCap terminal may be set lower than the MCS level for the general terminal. Therefore, the MCS offset may be set to 0 or -offset. That is, the MCS offset may not indicate a + offset. In this case, the number of bits required for signaling of the MCS offset may be reduced. Alternatively, the range of the MCS offset may be preset, and the base station may inform the terminal(s) of the preset range for the MCS offset.

10 is a conceptual diagram illustrating a first embodiment of a method for scheduling a frequency resource for RedCap SIB1.

Referring to FIG. 10 , RedCap SIB1 may be SIB1 for RedCap terminal(s), and general SIB1 may be SIB1 for general terminal(s). The frequency domain resource of RedCap SIB1 may be indicated by a combination of the first information and the second information. The first information may indicate a location of a frequency resource for RedCap SIB1 based on a frequency resource (eg, frequency domain) for general SIB1. The first information may be set as a + indication or a - indication. The + indication may indicate that the frequency resource for RedCap SIB1 is allocated on the frequency resource for general SIB1. - The indication may indicate that the frequency resource for RedCap SIB1 is allocated below the frequency resource for general SIB1. The second information may indicate the size (eg, the number of RBs) of a frequency resource for RedCap SIB1.

In the frequency domain, a frequency resource for RedCap SIB1 may be allocated below a frequency resource for general SIB1. In this case, the first information may mean - indication, and only the second information indicating the size of the frequency resource for RedCap SIB1 may be signaled. Frequency resources for other RedCap system information other than RedCap SIB1 may be allocated/indicated similarly or in the same manner as in FIG. 10 .

The RedCap terminal and the general terminal may perform the same initial access procedure. Alternatively, the RedCap terminal may perform a separate initial access procedure from that of a normal terminal. If the base station can distinguish the RedCap terminal from the normal terminal in the initial access procedure, the communication system can be efficiently operated. For example, when many terminals are concentrated in the base station, the RedCap terminal(s) from performing the initial access procedure may be blocked in advance for smooth service. That is, the base station can temporarily suspend the service for the RedCap terminal, and can focus on the service for the general terminal. Therefore, in the present application, a separate initial access procedure for a RedCap terminal (hereinafter referred to as "RedCap initial access procedure") and/or a method of distinguishing a RedCap terminal from a normal terminal in an initial access procedure will be proposed. In the embodiment, the initial access procedure for the general terminal may be referred to as a "general initial access procedure", and the initial access procedure for both the general terminal and the RedCap terminal may be referred to as a "common initial access procedure". In the embodiment, “the first communication node (eg, the base station) sets the parameter (eg, the information element)” or “the parameter is set” means that “the first communication node receives the setting information of the parameter” It may mean "transmitting to a second communication node (eg, a terminal).

In the common initial access procedure, the base station may allocate a physical random access channel (PRACH) preamble for a normal terminal and a PRACH preamble for a RedCap terminal differently. In this case, the base station may distinguish the normal terminal from the RedCap terminal based on the PRACH preamble in the common initial access procedure. Specifically, the base station may separately signal configuration information (eg, the number, index, and/or group of PRACH preambles) of the PRACH preamble for the RedCap terminal. The RedCap terminal may perform an initial access procedure based on configuration information of the PRACH preamble signaled by the base station. In this case, the base station may distinguish between a normal terminal and a RedCap terminal. The general terminal may perform a Type-1 random access procedure (eg, a 4-step random access procedure) or a Type-2 random access procedure (eg, a 2-step random access procedure). The PRACH preamble for the Type-1 random access procedure may be configured differently from the PRACH preamble for the Type-2 random access procedure.

A RACH occasion (RO) for a Type-1 random access procedure (hereinafter referred to as "Type-1 RO") and an RO for a Type-2 random access procedure (hereinafter referred to as "Type-2 RO") are mutually exclusive Can be set independently. In this case, R PRACH preambles may be configured in the UE for each valid RO (eg, a valid Type-1 RO and/or a valid Type-2 RO). In this case, R (hereinafter referred to as “R1”) for the Type-1 random access procedure may be different from R (hereinafter referred to as “R2”) for the Type-2 random access procedure. For example, when one SSB is mapped to one or more ROs, R1 PRACH preambles may be configured for a valid Type-1 RO, and R2 PRACH preambles may be configured for a valid Type-2 RO. . In this case, the index of the PRACH preamble may start from 0.

When N SSBs are mapped to one RO, R (eg, R1 and/or R2) may be set within a value obtained by dividing the total number of PRACH preambles (N _tot ) for the corresponding RO by N. N may be a natural number. The first SSB among the N SSBs may be mapped to PRACH preambles 0 to R-1, and the second SSB among the N SSBs may be mapped to the PRACH preambles N _tot /N to N _tot /N+R-1. have. As the SSB index increases, the starting point of the PRACH preamble index may increase by N _tot /N.

A common RO for the Type-1 random access procedure and the Type-2 random access procedure may be configured. In this case, R PRACH preambles for the Type-1 random access procedure and Q PRACH preambles for the Type-2 random access procedure may be configured for each valid common RO. Each of R and Q may be a natural number. The R PRACH preambles and Q PRACH preambles may be contiguously configured. For example, "when one SSB is mapped to one or more ROs, R PRACH preambles for the Type-1 random access procedure are configured, and Q PRACH preambles for the Type-2 random access procedure are configured", R PRACH preambles for Type-1 random access procedure (eg, PRACH preambles 0 to R-1) per common RO (eg, valid common RO) and Q PRACH for Type-2 random access procedure Preambles (eg, PRACH preambles R to R+Q-1) may be configured.

When N SSBs are mapped to one RO, each of R and Q may be set within a value obtained by dividing the total number of PRACH preambles (N _tot ) for the corresponding RO by N. N may be a natural number. Among the N SSBs, the first SSB may be mapped to PRACH preambles 0 to R-1 for the Type-1 random access procedure and PRACH preambles R to R+Q-1 for the Type-2 random access procedure. The second SSB among the N SSBs is the PRACH preamble N _tot /N to N _tot /N+R-1 for the Type-1 random access procedure and the PRACH preamble N _tot /N+R to for the Type-2 random access procedure. It may be mapped to N _tot /N+R+Q-1. As the SSB index increases, the starting point of the PRACH preamble index may be set to increase by N _tot /N.

A separate PRACH preamble (hereinafter, referred to as “RedCap PRACH preamble”) for the RedCap UE may be configured. When the RO for each of the Type-1 random access procedure and the Type-2 random access procedure is set, the method of setting the RedCap PRACH preamble is RedCap when a common RO for the Type-1 random access procedure and the Type-2 random access procedure is set. It may be different from the setting method of the PRACH preamble. When an RO for each of the Type-1 random access procedure and the Type-2 random access procedure is configured, P RedCap PRACH preambles may be configured through an additional parameter P for each RO. PRACH preambles 0 to R-1 may be used for a Type-1 random access procedure or a Type-2 random access procedure, and PRACH preambles R to R+P-1 may be configured as RedCap PRACH preambles.

In the Type-1 random access procedure, P for the RO may be set to P1, and in the Type-2 random access procedure, P for the RO may be set to P2, and P1 may be different from P2. Alternatively, the same P may be applied to both the RO of the Type-1 random access procedure and the RO of the Type-2 random access procedure. When the RedCap PRACH preamble is additionally set to the RO of the Type-1 random access procedure, the RedCap UE may perform the Type-1 random access procedure. When the RedCap PRACH preamble is additionally set to the RO of the Type-2 random access procedure, the RedCap UE may perform the Type-2 random access procedure.

When a common RO is configured for the Type-1 random access procedure and the Type-2 random access procedure, P RedCap PRACH preambles may be configured in the common RO using the additional parameter P. For each common RO, PRACH preambles 0 to R-1 for Type-1 random access procedure, PRACH preambles R to R+Q-1 for Type-2 random access procedure, and RedCap PRACH preambles R+Q to R+Q+ P-1 can be set. In this case, it may be preset for the RedCap terminal to perform the Type-1 random access procedure or the Type-2 random access procedure. It may be necessary to set the RedCap PRACH preamble for each of the Type-1 random access procedure and the Type-2 random access procedure in the common RO. In this case, P RedCap PRACH preambles for the Type-1 random access procedure may be configured using the parameter P, and O RedCap PRACH preambles for the Type-2 random access procedure may be configured using the parameter O. . In this case, for each common RO, PRACH preambles 0 to R-1 for Type-1 random access procedure, PRACH preambles R to R+Q-1 for Type-2 random access procedure, RedCap for Type-1 random access procedure PRACH preambles R+Q to R+Q+P-1, and RedCap PRACH preambles R+Q+P to R+Q+P+O-1 for Type-2 random access procedure can be configured.

When N SSBs are mapped to one RO, the PRACH preamble index may be defined within a value obtained by dividing the total number of PRACH preambles (N _tot ) in the corresponding RO by N. As the SSB index increases, the starting point of the PRACH preamble index may be set to increase by N _tot /N. Enable and/or disable for "operation of distinguishing a normal terminal from a RedCap terminal through setting of the RedCap PRACH preamble" may be set by system information. Parameter(s) for configuring the RedCap PRACH preamble may be signaled through system information.

As another method for distinguishing between a normal terminal and a RedCap terminal in the common initial access procedure, the starting position of an RO for a general terminal (hereinafter referred to as "general RO") in the frequency domain and an RO for a RedCap terminal (hereinafter referred to as "RedCap") The starting position of "RO") may be set differently. In order to set the normal RO and the RedCap RO differently, the base station may separately set the start position of the RedCap RO in the frequency domain in units of RBs by using an additional parameter. When the RedCap terminal supports both the Type-1 random access procedure and the Type-2 random access procedure, the frequency domain start position of the RedCap RO for each of the Type-1 random access procedure and the Type-2 random access procedure is set in units of RBs can be The frequency domain start position of the RedCap RO and the number of RedCap ROs in the frequency domain may be set together.

In order to distinguish the normal RO from the RedCap RO, the start position of the normal RO and the start position of the RedCap RO in the time domain may be set differently. The position of the RO in the time domain may be determined by a PRACH configuration index. The PRACH configuration index may be set so that the normal RO and the RedCap RO do not overlap in the time domain. In this case, the base station can distinguish between a normal terminal and a RedCap terminal. A combination of at least one of "a method of differently setting the start positions of the normal RO and the RedCap RO in the frequency domain" or "a method of setting the normal RO and the RedCap RO so that they do not overlap in the time domain" may be applied. Enabling and/or disabling of "operation of distinguishing a normal terminal from a RedCap terminal through configuration of a RedCap RO (eg, a separate RACH resource for a RedCap terminal)" may be set by system information. Parameter(s) for configuring the RedCap RO may be signaled to the terminal(s) through system information.

Alternatively, in the Type-1 random access procedure, the general terminal and the RedCap terminal may use the same PRACH preamble, and after receiving a random access response (RAR), the general terminal indicates its own terminal type (ie, a general terminal). Msg3 (eg, PUSCH) including information (hereinafter referred to as "terminal type indicator") may be transmitted, and after reception of the RAR, the RedCap terminal transmits information indicating its terminal type (ie, RedCap terminal). including Msg3 (eg, PUSCH) may be transmitted. The base station may distinguish between a normal terminal and a RedCap terminal based on the information included in Msg3. "When the Msg2 (ie, RAR) received from the base station requests transmission of the terminal type indicator", "when the base station can recognize the RedCap terminal", or "when the base station provides a service for the RedCap terminal" , each of the general terminal and the RedCap terminal may transmit Msg3 including the terminal type indicator. If the base station cannot recognize the RedCap terminal" and/or "the base station does not provide a service for the RedCap terminal", the base station may not interpret the terminal type indicator included in Msg3.

The request of the terminal type indicator is Msg2 as well as system information (eg, MIB and / or SIB), RRC message, MAC CE, or DCI (eg, DCI scheduling system information) to be transmitted through at least one can "Information indicating whether the base station recognizes the RedCap terminal" and / or "information indicating whether the base station provides a service for the RedCap terminal" is system information (eg, MIB and / or SIB), RRC It may be transmitted through at least one of a message, MAC CE, Msg2 (ie, RAR), or DCI (eg, DCI for scheduling system information).

In the Type-2 random access procedure, the UE may transmit MsgA composed of a PRACH preamble and a PUSCH. In this case, different PRACH preambles and different ROs may be configured to distinguish a normal UE from a RedCap UE. The base station may transmit RACH configuration information including configuration information of the PRACH preamble and/or configuration information of the RO to the terminal(s). When transmitting MsgA in the Type-2 random access procedure, the UE may transmit the PRACH preamble and the PUSCH associated with the PRACH preamble together. Based on the PRACH preamble configured for each of the general terminal and the RedCap terminal and the PUSCH associated with the corresponding PRACH preamble, the terminal type of each terminal may be identified. Alternatively, the normal UE and the RedCap UE may be distinguished based on the PUSCH of MsgA. Specifically, the PRACH preamble of MsgA may be identically configured for a normal UE and a RedCap UE, and the MsgA PUSCH resource (ie, the PUSCH resource of MsgA) may be set differently to distinguish between a normal UE and a RedCap UE. That is, the base station may configure the MsgA PUSCH resource for the general terminal and the MsgA PUSCH resource for the RedCap terminal differently. The MsgA PUSCH resource for the normal UE may be orthogonal to the MsgA PUSCH resource for the RedCap UE. Here, the resource of the MsgA PUSCH may be at least one of a time resource, a frequency resource, and a code (eg, a DM-RS sequence having orthogonality).

After detecting the MsgA PRACH preamble, the base station may perform a decoding operation on the MsgA PUSCH resource configured for each terminal type. In this case, the reception complexity of the base station may increase. Alternatively, the base station may set the same MsgA PUSCH resource for the general terminal and the MsgA PUSCH resource for the RedCap terminal, and the MsgA PUSCH may include a terminal type indicator. In this case, the base station may acquire the MsgA PUSCH by performing decoding on the MsgA PUSCH resource regardless of the terminal type, and based on the terminal type indicator included in the MsgA PUSCH, a normal terminal and a RedCap terminal may be distinguished. Accordingly, the reception complexity of the base station may not increase.

Whether the terminal type indicator is used may be signaled by at least one of system information (eg, MIB or SIB), an RRC message, MAC CE, or DCI (eg, DCI for scheduling system information). In the Type-2 random access procedure, the UE may transmit MsgA including the PRACH preamble and PUSCH to the base station, and when the MsgA is detected and received, the UE may transmit MsgB to the UE. If "the MsgA PRACH preamble is detected and the reception of the MsgA PUSCH fails", the base station may instruct the terminal to re-perform the Type-2 random access procedure (eg, retry MsgA transmission). Alternatively, the base station may request the terminal to transmit only the PRACH preamble by instructing the terminal to switch from the Type-2 random access procedure to the Type-1 random access procedure.

When the Type-2 random access procedure is switched to the Type-1 random access procedure, if the normal terminal and the RedCap terminal are not distinguished by the PRACH preamble setting, the base station may not be able to distinguish the normal terminal from the RedCap terminal. Therefore, when a normal terminal and a RedCap terminal are distinguished by the MsgA PUSCH in the Type-2 random access procedure, when MsgA reception fails, the Type-2 random access procedure is not switched from the Type-2 random access procedure to the Type-1 random access procedure. It may be configured that the access procedure is continuously performed. That is, the base station may preset prohibition of fallback to the Type-1 random access procedure.

When a normal terminal and a RedCap terminal are distinguished through Msg3 in the Type-1 random access procedure, when the detection and/or reception of MsgA fails, the Type-2 random access procedure can be switched to a Type-1 random access procedure, The base station may distinguish between a normal terminal and a RedCap terminal based on Msg3. In this case, the base station may determine "whether to continue performing the Type-2 random access procedure" and/or "whether to switch from the Type-2 random access procedure to the Type-1 random access procedure".

The initial UL BWP for the random access procedure may be set differently for each terminal type (eg, a general terminal or a RedCap terminal). In this case, the base station may distinguish the terminal performing the random access procedure based on the initial UL BWP. The base station may set the initial UL BWP of the general terminal and the RedCap terminal differently through system information. An initial UL BWP configured for a normal UE may be referred to as a “general initial UL BWP”, and an initial UL BWP configured for a RedCap UE may be referred to as a “RedCap initial UL BWP”. A normal UE may perform a random access procedure in a normal initial UL BWP, and a RedCap UE may perform a random access procedure in a RedCap initial UL BWP. The base station can distinguish the type of terminal performing the random access procedure by monitoring each of the general initial UL BWP and the RedCap initial UL BWP.

The PRACH preamble and RO may be independently configured for each of the general initial UL BWP and the RedCap initial UL BWP. The PRACH preamble and RO for the general initial UL BWP may be applied to the RedCap initial UL BWP. However, when the general initial UL BWP is different from the RedCap initial UL BWP, it may be difficult to apply the set value(s) (eg, PRACH preamble and/or RO) for the general initial UL BWP to the RedCap initial UL BWP. . In this case, the number of ROs in the frequency domain may be limited, and parameter(s) other than the number of ROs in the frequency domain may be reused or reinterpreted. For example, the number of ROs in the frequency domain may be limited to one.

Alternatively, the SSB for the general terminal and the SSB for the RedCap terminal may be configured independently. Each of the normal terminal and the RedCap terminal may perform an initial access procedure (eg, a random access procedure) based on the independently configured SSB. In this case, the base station can distinguish the terminal type performing the initial access procedure. The SSB for the general terminal may be referred to as a general SSB, and the SSB for the RedCap terminal may be referred to as a RedCap SSB. The base station may transmit a normal SSB and a RedCap SSB, and may support an initial access procedure based on the general SSB and an initial access procedure based on the RedCap SSB.

In the Type-1 random access procedure, the UE may transmit the PRACH preamble and may receive Msg2 (ie, RAR) from the base station through the PDSCH. Scheduling information of PDSCH may be obtained from DCI scrambled by RA (random access)-RNTI. RA-RNTI may be determined by RO as shown in Equation 5 below.

는 PRACH 프리앰블이 전송되는 UL 캐리어를 지시할 수 있다. NUL(Normal Uplink)에서

는 0으로 설정될 수 있고, SUL(Supplementary Uplink)에서

는 1로 설정될 수 있다. 따라서 시간 도메인에서 일반 단말의 RO의 위치와 RedCap 단말의 RO의 위치가 동일한 경우, 일반 단말과 RedCap 단말은 동일한 RA-RNTI를 사용할 수 있다. The range of s _id may be 0≤s _id <14, and s _id may indicate an index of the first symbol of the RO (eg, the first OFDM symbol). The range of t _id may be 0≤t _id <80, and t _id may indicate the index of the first slot of the RO in the system frame. t _id may be determined according to the size of the subcarrier. The range of f _id may be 0≤f _id <8, and f _id may indicate an RO index in the frequency domain.

may indicate the UL carrier through which the PRACH preamble is transmitted. In NUL (Normal Uplink)

may be set to 0, and in SUL (Supplementary Uplink)

may be set to 1. Therefore, when the location of the RO of the general terminal and the location of the RO of the RedCap terminal are the same in the time domain, the general terminal and the RedCap terminal may use the same RA-RNTI.

Even when the location of the RO of the general terminal and the location of the RO of the RedCap terminal are set differently in the frequency domain, since f _id is a logical index of the RO in the frequency domain, the f _id of the general terminal and the f _id of the RedCap terminal have the same value. can have Therefore, even when the normal UE and the RedCap UE transmit different PRACH preambles, the base station may not be able to distinguish the RA-RNTI of the normal UE and the RA-RNTI of the RedCap UE. In the Type-2 random access procedure, the MSGB-RNTI for reception of Msg-B may be determined according to the location of the RO to which the PRACH preamble included in Msg-A is transmitted. For example, MSGB-RNTI may be determined based on Equation 6 below.

각각은 수학식 5에서 s_id, t_id, f_id, 및

와 동일할 수 있다. 수학식 5와 수학식 6의 구별을 위해, 수학식 6에 14×80×8×2가 추가될 수 있다. 일반 단말의 RA-RNTI 및 MSGB-RNTI와 RedCap 단말의 RA-RNTI를 구분하기 위해서, RedCap 단말을 위한 별도의 RA-RNTI는 사용될 수 있다. 이 동작을 지원하기 위해, 일반 단말의 RA-RNTI에 추가 오프셋이 적용될 수 있다. 예를 들어, RedCap 단말의 RA-RNTI는 아래 수학식 7에 기초하여 결정될 수 있다. RedCap 단말의 RA-RNTI는 RA-R-RNTI로 지칭될 수 있다. 수학식 7은 수학식 5에 14×80×8×4가 추가된 수학식일 수 있다.In Equation 6, s _id , t _id , f _id , and

Each of s _id , t _id , f _id , and

can be the same as In order to distinguish between Equation 5 and Equation 6, 14×80×8×2 may be added to Equation 6 . In order to distinguish the RA-RNTI and MSGB-RNTI of the general terminal and the RA-RNTI of the RedCap terminal, a separate RA-RNTI for the RedCap terminal may be used. In order to support this operation, an additional offset may be applied to the RA-RNTI of a general terminal. For example, the RA-RNTI of the RedCap terminal may be determined based on Equation 7 below. The RA-RNTI of the RedCap terminal may be referred to as an RA-R-RNTI. Equation 7 may be an equation in which 14×80×8×4 is added to Equation 5.

The RA-R-RNTI determined by Equation 7 may not overlap with the RA-RNTI and MSGB-RNTI of the general terminal. When the RedCap terminal uses one of the Type-1 random access procedure and the Type-2 random access procedure, the RedCap terminal and/or the base station does not overlap with each of the RA-RNTI and MSGB-RNTI of the general terminal by using Equation 7 You can set an RA-R-RNTI that does not When the RedCap terminal supports both the Type-1 random access procedure and the Type-2 random access procedure, the RA-R-RNTI for the Type-1 random access procedure and the RA-RNTI of the RedCap terminal for the Type-2 random access procedure (hereinafter referred to as "MSGB-R-RNTI") is required.

When the RA-R-RNTI for the Type-1 random access procedure is set based on Equation 7, the MSGB-R-RNTI for the Type-2 random access procedure is 14×80×8×6 in Equation 5 It may be set based on the added equation. In this case, since the range of values for MSGB-R-RNTI is 62721 to 71680, the value of MSGB-R-RNTI may exceed 65519, which is the maximum value that other RNTIs can have except for some RNTIs defined for special purposes. . Therefore, MSGB-R-RNTI may be difficult to use. In order to solve the above-described problem, a modular operation may be used to calculate the MSGB-R-RNTI as shown in Equation 8 below.

Equation 8 may be an equation in which 14×80×8×6 is added to Equation 5. A modular operation may be used so that the value of MSGB-R-RNTI is set within an acceptable value. When the applied value of the modular operation is set to 2 ¹⁶ , the value of MSG-R-RNTI may be set to a value of P (paging)-RNTI, SI (system information)-RNTI, or reserve RNTI. In order to prevent such a problem, the applied value of the modular operation may be set to 65520 as shown in Equation 9 below.

로 지칭될 수 있다. 이 경우, RA-R-RNTI는 아래 수학식 10에 기초하여 결정될 수 있고, MSGB-R-RNTI는 아래 수학식 11에 기초하여 결정될 수 있다.In Equations 8 and 9, a modular operation may be used so that the value of MSG-R-RNTI does not exceed the range of allowed values. The modular operation may also be applied to equation(s) other than equations (8) and (9). Alternatively, the range of f _id in the equation(s) for calculating the RNTI may be reduced. 1, 2, 4, or 8 ROs may be multiplexed according to configuration in the frequency domain. In this case, the range of f _id indicating the RO index may be 0≤f _id <8. The number of RedCap terminals in the cell may be smaller than the number of normal terminals. Therefore, the number of RO multiplexing for the RedCap terminal in the frequency domain may be limited to be less than 8. For example, the maximum value of f _id for the RedCap terminal may be 8 or less. The maximum value of f _id is

may be referred to as In this case, RA-R-RNTI may be determined based on Equation 10 below, and MSGB-R-RNTI may be determined based on Equation 11 below.

Equation 10 may be an equation for calculating the RA-R-RNTI for the RedCap terminal in the Type-1 random access procedure. Equation 11 may be an equation for calculating the MSGB-R-RNTI for the RedCap terminal in the Type-2 random access procedure. When Equations 10 and 11 are used, the RA-R-RNTI and MSGB-R-RNTI for the RedCap terminal may not overlap with the RA-RNTI and MSGB-RNTI for the general terminal.

=4"의 제한에 따라 계산된 결과일 수 있다. 즉,

는 8에서 4로 감소될 수 있다. RNTI들은 서로 중복되지 않게 설정될 수 있다. 또한, RNTI들은 최대값인 65519를 넘지 않게 설정될 수 있다. 상술한 실시예는 Type-1 랜덤 접속 절차 또는 Type-2 랜덤 접속 절차 중에서 하나 이상의 지원하는 경우에 적용될 수 있다. Type-1 랜덤 접속 절차 및 Type-2 랜덤 접속 절차 중에서 하나를 지원하는 경우에도, RNTI는

의 제한에 따라 계산될 수 있다. 상술한 실시예는

가 4 아닌 다른 값으로 설정(예를 들어, 감소)된 경우에도 적용될 수 있다. RNTI의 계산 절차에서 f_id뿐만 아니라 s_id의 값 및/또는 t_id의 값은 제한될 수 있다. s_id는 RO의 첫 번째 심볼 인덱스를 지시할 수 있고, t_id는 시스템 프레임에서 RO의 첫 번째 슬롯 인덱스를 지시할 수 있다. RNTI는 상술한 방법들의 조합에 의해 계산될 수 있다. RedCap 단말을 위한 RA-RNTI는 RA-R-RNTI 대신에 다른 용어(예를 들어, RA-RNTI)로 지칭될 수 있다. RA-RNTI는 일반 단말과 RedCap 단말을 위해 동일하게 사용될 수 있다. RedCap 단말을 위한 MSGB-RNTI는 MSGB-R-RNTI 대신에 다른 용어(예를 들어, MSGB-RNTI)로 지칭될 수 있다. MSGB-RNTI는 일반 단말과 RedCap 단말을 위해 동일하게 사용될 수 있다.Table 5 shows "RA-RNTI and MSGB-RNTI for general terminal" calculated by Equation 5, Equation 6, Equation 10, and Equation 11, and RA-R-RNTI and MSGB-R for RedCap terminal -RNTI". In Table 5, RA-R-RNTI and MSGB-R-RNTI are "

It may be a calculated result according to the limitation of =4". That is,

can be reduced from 8 to 4. RNTIs may be set not to overlap with each other. Also, the RNTIs may be set not to exceed the maximum value of 65519. The above-described embodiment may be applied to a case in which at least one of a Type-1 random access procedure and a Type-2 random access procedure is supported. Even if one of the Type-1 random access procedure and the Type-2 random access procedure is supported, the RNTI is

can be calculated according to the limits of The above-described embodiment

It may be applied even when is set (eg, decreased) to a value other than 4 . In the calculation procedure of the RNTI, not only f _id but also the value of s _id and/or the value of t _id may be limited. s _id may indicate the first symbol index of the RO, and t _id may indicate the first slot index of the RO in the system frame. The RNTI may be calculated by a combination of the above-described methods. The RA-RNTI for the RedCap UE may be referred to as another term (eg, RA-RNTI) instead of the RA-R-RNTI. The RA-RNTI may be used equally for a general terminal and a RedCap terminal. MSGB-RNTI for RedCap UE may be referred to as another term (eg, MSGB-RNTI) instead of MSGB-R-RNTI. MSGB-RNTI can be equally used for a general terminal and a RedCap terminal.

A Type1-PDCCH CSS set in which DCI for scheduling RAR (hereinafter, referred to as “RAR scheduling DCI”) is received may be independently configured for each of the RedCap terminal and the general terminal. In an embodiment, the Type1-PDCCH CSS set for a RedCap terminal may be referred to as a "RedCap Type1-PDCCH CSS set", and the Type1-PDCCH CSS set for a general terminal may be referred to as a "general Type1-PDCCH CSS set". . A normal UE can monitor the scrambled RAR scheduling DCI through RA-RNTI or MSGB-RNTI in the general Type1-PDCCH CSS set, and the RedCap UE can monitor the RA-R-RNTI or MSGB-R- in the RedCap Type1-PDCCH CSS set. The scrambled RAR scheduling DCI may be monitored through the RNTI. Therefore, even when the same RNTI is configured between the normal UE and the RedCap UE, each of the normal UE and the RedCap UE may successfully receive the RAR scheduling DCI. In the time and/or frequency domain, the general Type1-PDCCH CSS set may not overlap with the RedCap Type1-PDCCH CSS set. The general Type1-PDCCH CSS set and the RedCap Type1-PDCCH CSS set may be configured in different slots. Alternatively, the general Type1-PDCCH CSS set and the RedCap Type1-PDCCH CSS set may be set in different symbols within the same slot.

A CSS set can be set within 3 symbols in a slot. The three symbols for which the CSS set is set may be located in a front area (eg, symbols from the first symbol to the third symbol) or an arbitrary area within the slot. The RedCap Type1-PDCCH CSS set may be set in any symbol(s) in the slot so that the efficiency of resource use is improved and the general terminal and the RedCap terminal are monitored together in one slot within a limited bandwidth. In order to distinguish the RAR scheduling DCI even when the RNTIs of the RedCap terminal and the normal terminal are set identically, the RAR window of the RedCap terminal (hereinafter referred to as "RedCap RAR window") is the RAR window of the general terminal (hereinafter, "general RAR window"). ") and may be set differently. The general RAR window may start from the first symbol of the earliest CORESET in which the Type1-PDCCH CSS set is set after the RO in which the PRACH preamble is transmitted. The general RAR window may be set in units of slots.

When f _id is the same in the equation for calculating the RA-RNTI, the RA-RNTI of the general terminal may be the same as the RA-RNTI of the RedCap terminal. When the RA-RNTI of the general terminal is the same as the RA-RNTI of the RedCap terminal, the start time of the general RAR window may be the same as the start time of the RedCap RAR window. In order to solve the above-mentioned problem, the RedCap RAR window may be set separately from the general RAR window. When the RedCap RAR window and the normal RAR window are set to be distinguished, the RedCap RAR window may be set after the normal RAR window in the time domain. In order to prevent overlap between the RedCap RAR window and the normal RAR window starting after the RO, the size (eg, length) of the RedCap RAR window may be determined in consideration of the offset from the corresponding RO. In addition, the start time of the RedCap RAR window may be determined in consideration of the offset from the corresponding RO.

In order to support the above-described operation(s), the base station may transmit a signaling message including information on the offset and/or size of the RAR window (eg, RedCap RAR window and/or general RAR window) to the terminal(s). have. In this case, in order to reduce signaling overhead, the RedCap RAR window may be continuously configured with the general RAR window in the time domain. The size of the RedCap RAR window may be set in the RedCap terminal, and the start time of the RedCap RAR window may be implicitly indicated to the RedCap terminal. For example, the RedCap terminal may set the RedCap RAR window from the end point of the normal RAR window. In this case, the general RAR window and the RedCap RAR window may be set consecutively. Alternatively, the size of the RedCap RAR window may be implicitly indicated. For example, the size of the RedCap RAR window may be assumed to be the same as the size of the normal RAR window. In this case, the RedCap terminal may determine that the size of the RedCap RAR window is the same as the size of the normal RAR window, and may start the RedCap RAR window at the end of the normal RAR window. Accordingly, signaling overhead can be reduced.

When the base station can distinguish the normal terminal from the RedCap terminal at an early point in the initial access procedure, the initial access procedure of the RedCap terminal may be limited according to the situation of the communication system. When traffic processing is difficult due to the increase in the number of terminals in the base station, the base station may block the initial access procedure of the RedCap terminal to temporarily suspend the service to the RedCap terminal(s), and may provide preferential service to general terminals have. In the present application, a method of blocking the connection attempt of the RedCap terminal from the initial access procedure will be proposed.

The UE may receive the SSB, and may obtain configuration information of CORESET #0 and configuration information of the Type0-PDCCH CSS set for receiving system information (eg, RMSI) from the PBCH included in the SSB. By setting the frequency resource of CORESET#0 to be larger than the supportable bandwidth of the RedCap terminal, the initial access procedure of the RedCap terminal may be blocked in advance. The bandwidth supported by the RedCap terminal may be set to be smaller than the bandwidth of the general terminal. The base station may block the initial access procedure of the RedCap terminal in advance by setting the frequency resource of CORESET #0 to be larger than the bandwidth supported by the RedCap terminal. If the frequency resource of CORESET #0 is set to be larger than the bandwidth supported by the RedCap terminal, the RedCap terminal may determine that access to the corresponding base station is impossible, and may find a new base station.

Alternatively, the base station may block the initial access procedure of the RedCap terminal using DCI scheduling SIB1 (hereinafter referred to as "SIB1 DCI"). Among the reserved bits included in DCI format 1_0 (eg, SIB1 DCI) scrambled by SI-RNTI, 1 bit may be used as an indicator for access restriction of the RedCap UE. A general terminal (eg, a legacy terminal) may receive SIB1 based on existing scheduling information because it does not consider reserved bits included in DCI format 1_0. The RedCap terminal may determine whether to restrict the access of the RedCap terminal based on the indicator included in DCI format 1_0. When the access of the RedCap terminal is not restricted, the RedCap terminal may receive SIB1 based on the scheduling information. When the access of the RedCap terminal is restricted, the RedCap terminal may not receive SIB1.

The methods according to the present application may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

A method of operating a base station in a communication system, comprising:
generating first random access channel (RACH) configuration information for a normal terminal;
generating second RACH configuration information for a reduced capability (RedCap) terminal;
transmitting a message including the first RACH configuration information and the second RACH configuration information; and
Comprising the step of performing a random access (random access) procedure with the first terminal based on the message,
The terminal type of the first terminal is identified based on the first RACH configuration information and the second RACH configuration information, and the terminal type is the general terminal or the RedCap terminal. The method according to claim 1,
The first RACH configuration information includes configuration information of a first physical random access channel (PRACH) preamble for the general terminal, and the second RACH configuration information includes configuration information of a second PRACH preamble for the RedCap terminal and the terminal type is identified based on a type of a PRACH preamble received in the random access procedure, and the type of the PRACH preamble is the first PRACH preamble or the second PRACH preamble. The method according to claim 1,
The first RACH configuration information includes configuration information of a first RO (RACH occasion) for the general terminal, and the second RACH configuration information includes configuration information of a second RO for the RedCap terminal, the terminal A type is identified based on a type of an RO for which a PRACH preamble is received in the random access procedure, and the type of the RO is the first RO or the second RO. The method according to claim 1,
Information for enabling or disabling the operation of distinguishing the normal terminal from the RedCap terminal based on the first RACH configuration information and the second RACH configuration information is included in the message. how it works. The method according to claim 1,
Information indicating whether at least one of a Type-1 random access procedure and a Type-2 random access procedure is supported is included in the message. The method according to claim 1,
The step of performing the random access procedure comprises:
receiving Msg1 from the first terminal;
transmitting Msg2 to the first terminal in response to the Msg1;
receiving Msg3 from the first terminal; and
Based on the indicator included in the Msg3 comprising the step of identifying the terminal type as the general terminal or the RedCap terminal, the operating method of the base station. 7. The method of claim 6,
Information for enabling or disabling the operation of distinguishing the normal terminal from the RedCap terminal based on the indicator is included in the message. The method according to claim 1,
The step of performing the random access procedure comprises:
receiving MsgA including a PRACH preamble and a physical uplink shared channel (PUSCH) from the first terminal; and
Based on the transmission resource of the PUSCH, the method of operating a base station comprising the step of identifying the terminal type as the general terminal or the RedCap terminal. The method according to claim 1,
The step of performing the random access procedure comprises:
receiving MsgA including a PRACH preamble and a PUSCH from the first terminal; and
Based on the indicator included in the PUSCH, the method of operating a base station comprising the step of identifying the terminal type as the normal terminal or the RedCap terminal. The method according to claim 1,
The step of performing the random access procedure comprises:
receiving a PRACH preamble from the first terminal that is the RedCap terminal;
calculating a second radio network temporary identifier (RNTI) based on the transmission resource of the PRACH preamble; and
transmitting downlink control information (DCI) scrambled by the second RNTI to the RedCap terminal,
The value of the second RNTI is a result of a second equation in which an offset is applied to the first equation for calculating the first RNTI of the general terminal. 11. The method of claim 10,
The offset is 14×80×8×4, the operating method of the base station. 11. The method of claim 10,
In order to prevent the value of the second RNTI from deviating from a preset range due to the offset, a modular operation is applied to the second equation. 11. The method of claim 10,
The second RNTI is a random access (RA)-R-RNTI for a Type-1 random access procedure or an MSGB-R-RNTI for a Type-2 random access procedure. As a base station in a communication system,
processor;
a memory in electronic communication with the processor; and
including instructions stored in the memory;
When the instructions are executed by the processor, the instructions cause the base station to:
generate first random access channel (RACH) configuration information for a normal terminal;
generate second RACH configuration information for a reduced capability (RedCap) terminal;
transmit a message including the first RACH configuration information and the second RACH configuration information; and
operate to cause performing a random access procedure with the first terminal based on the message,
The terminal type of the first terminal is identified based on the first RACH configuration information and the second RACH configuration information, and the terminal type is the general terminal or the RedCap terminal. 15. The method of claim 14,
The first RACH configuration information includes configuration information of a first physical random access channel (PRACH) preamble for the general terminal, and the second RACH configuration information includes configuration information of a second PRACH preamble for the RedCap terminal and the terminal type is identified based on a type of a PRACH preamble received in the random access procedure, and the type of the PRACH preamble is the first PRACH preamble or the second PRACH preamble. 15. The method of claim 14,
The first RACH configuration information includes configuration information of a first RO (RACH occasion) for the general terminal, and the second RACH configuration information includes configuration information of a second RO for the RedCap terminal, the terminal A type is identified based on a type of an RO for which a PRACH preamble is received in the random access procedure, and the type of the RO is the first RO or the second RO. 15. The method of claim 14,
When performing the random access procedure, the instructions are that the base station,
receive Msg1 from the first terminal;
transmit Msg2 to the first terminal in response to the Msg1;
receive Msg3 from the first terminal; and
The base station operable to cause identification of the terminal type as the general terminal or the RedCap terminal based on the indicator included in the Msg3. 15. The method of claim 14,
When performing the random access procedure, the instructions are that the base station,
receiving MsgA including a PRACH preamble and a physical uplink shared channel (PUSCH) from the first terminal; and
A base station operable to cause checking of the terminal type as the general terminal or the RedCap terminal based on the transmission resource of the PUSCH. 15. The method of claim 14,
When performing the random access procedure, the instructions are that the base station,
receiving MsgA including a PRACH preamble and a PUSCH from the first terminal; and
Based on the indicator included in the PUSCH, the base station operates to cause the identification of the terminal type as the general terminal or the RedCap terminal. 15. The method of claim 14,
When performing the random access procedure, the instructions are that the base station,
receive a PRACH preamble from the first terminal that is the RedCap terminal;
calculating a second radio network temporary identifier (RNTI) based on the transmission resource of the PRACH preamble; and
operative to cause transmission of downlink control information (DCI) scrambled by the second RNTI to the RedCap terminal,
The value of the second RNTI is a result of a second equation in which an offset is applied to the first equation for calculating the first RNTI of the normal terminal.

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