KR20230004255A - Method and apparatus for communication in network having asymmetric uplink and downlink - Google Patents

Abstract

A random access method performed by a terminal includes receiving configuration information of SSB resources from a base station; Receiving configuration information of PRACH resources from the base station; Receiving an SSB from the base station in a first SSB resource among the SSB resources; configuring a PRACH resource set associated with the first SSB resource based on configuration information of the PRACH resources; and transmitting a first PRACH in a first PRACH resource belonging to the PRACH resource set and transmitting a second PRACH in a second PRACH resource belonging to the PRACH resource set, wherein the first PRACH and the second PRACH are transmitted. includes the same preamble sequence and is transmitted using different beams.

Description

Communication method and apparatus for uplink and downlink asymmetric networks

The present invention relates to a communication method and apparatus for an uplink and downlink asymmetric network, and more particularly, to a method and method for performing communication between a base station and a terminal in an asymmetric communication system in which transmission/reception points for uplink and downlink are asymmetrically arranged. It is about a device for

Communication systems are continuously evolving to expand communication infrastructure for the realization of a hyper-connected society. For example, the NR communication system may support a frequency band up to around 100 GHz as well as a frequency band of 6 GHz or less, and compared to a conventional communication system (eg, a long-term evolution (LTE) communication system) More diverse services and scenarios can be supported. For example, a usage scenario of the NR communication system may include enhanced mobile broadband (eMBB), ultra reliable low latency communication (URLLC), and massive machine type communication (mMTC). In addition, the 6G communication system being discussed recently is expected to enable more diverse services and user experiences by utilizing THz frequency band, artificial intelligence, satellite communication, and quantum technology. There are various requirements in the industry that these communication systems must satisfy, and advanced communication technology is required to achieve them.

An object of the present invention to solve the above problems is to provide a method of operating a terminal and a method of operating a base station in an asymmetric network communication system.

Another object of the present invention to solve the above problems is to provide a configuration of a terminal and a base station operating in an asymmetric network communication system.

A method of a terminal according to a first embodiment of the present invention for achieving the above object includes: receiving configuration information of SSB (synchronization signal block) resources from a base station; Receiving configuration information of physical random access channel (PRACH) resources from the base station; Receiving an SSB from the base station in a first SSB resource among the SSB resources; configuring a PRACH resource set associated with the first SSB resource based on configuration information of the PRACH resources; and transmitting a first PRACH in a first PRACH resource belonging to the PRACH resource set and transmitting a second PRACH in a second PRACH resource belonging to the PRACH resource set, wherein the first PRACH and the second PRACH are transmitted. may include the same preamble sequence and be transmitted using different beams.

The first PRACH resource and the second PRACH resource may be mapped to different time resources.

A beam used for transmission of the first PRACH and a beam used for transmission of the second PRACH may be determined without correspondence with a beam used for receiving the SSB by the terminal.

A transmission and reception point (TRP) transmitting the SSB may be the same as or different from a TRP receiving the first PRACH and/or the second PRACH.

The first PRACH resource may be further combined with a second SSB resource belonging to the SSB resources.

The method further includes receiving information about an association relationship between the SSB resources and the PRACH resources from the base station, and the PRACH resource set associated with the first SSB resource is the association relationship It can be configured based on information about.

The PRACH resource set coupled to the first SSB resource may be configured based on an index of the first SSB resource and indexes of PRACH resources belonging to the PRACH resource set.

When the configuration information of the PRACH resources indicates M PRACH resources, the PRACH resource set coupled to the first SSB resource is composed of N PRACH resources, M and N are natural numbers, respectively, and N is M and N respectively. can be equal or smaller.

The first PRACH and the second PRACH may be transmitted with the same transmission power within the same transmission period or may be transmitted with different transmission power within the same transmission period.

A method of a base station according to a second embodiment of the present invention for achieving the above object includes: transmitting configuration information of SSB resources to a terminal; Transmitting configuration information of PRACH resources to the terminal; Transmitting an SSB in a first SSB resource among the SSB resources; and receiving a first PRACH in a first PRACH resource belonging to a PRACH resource set associated with the first SSB resource from the terminal or receiving a second PRACH in a second PRACH resource belonging to the PRACH resource set. In addition, the first PRACH and the second PRACH may include the same preamble sequence and be received using different beams.

The first PRACH resource and the second PRACH resource may be mapped to different time resources.

A beam used for reception of the first PRACH and a beam used for reception of the second PRACH may not have correspondence with a beam used for transmitting the SSB.

A transmission and reception point (TRP) transmitting the SSB may be the same as or different from a TRP receiving the first PRACH and/or the second PRACH.

The first PRACH resource may be further combined with a second SSB resource belonging to the SSB resources.

The method further includes transmitting information about an association relationship between SSB resources and the PRACH resources to the terminal, and the PRACH resource set associated with the first SSB resource corresponds to the association relationship. It can be configured based on information about.

The PRACH resource set coupled to the first SSB resource may be configured based on an index of the first SSB resource and indexes of PRACH resources belonging to the PRACH resource set.

When the configuration information of the PRACH resources indicates M PRACH resources, the PRACH resource set coupled to the first SSB resource is composed of N PRACH resources, M and N are natural numbers, respectively, and N is M and N respectively. can be equal or smaller.

A terminal according to a third embodiment of the present invention for achieving the above object includes: a processor; instructions executed by the processor; and a memory for storing the instructions, which, when executed by the processor, cause the terminal to: receive configuration information of SSB resources from a base station; receiving configuration information of PRACH resources from the base station; Receiving an SSB from the base station in a first SSB resource among the SSB resources; configuring a PRACH resource set associated with the first SSB resource based on configuration information of the PRACH resources; and transmitting a first PRACH in a first PRACH resource belonging to the PRACH resource set and transmitting a second PRACH in a second PRACH resource belonging to the PRACH resource set, wherein the first PRACH and the second PRACH are transmitted. PRACH may include the same preamble sequence and be transmitted using different beams.

A beam used for transmission of the first PRACH and a beam used for transmission of the second PRACH may be determined without correspondence with a beam used for receiving the SSB by the terminal.

A transmission and reception point (TRP) transmitting the SSB may be the same as or different from a TRP receiving the first PRACH and/or the second PRACH.

According to an embodiment of the present invention, a communication method and apparatus for an uplink/downlink asymmetric network may be provided. Accordingly, the performance of the communication system can be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
Figure 2 is a block diagram showing a first embodiment of a device.
3 is a conceptual diagram illustrating a first embodiment of a configuration of a communication network and a signal transmission method based thereon.
4 is a conceptual diagram illustrating a first embodiment of an initial access method based on association between downlink resources and uplink resources.
5A and 5B are conceptual diagrams illustrating a configuration of an uplink/downlink asymmetric network using multiple TRPs and a first embodiment of a signal transmission method based thereon.
6 is a conceptual diagram illustrating a first embodiment of an initial access method based on uplink beam sweeping.
7 is a conceptual diagram illustrating a first embodiment of a mutual coupling method between downlink resources and uplink resources.
8A is a conceptual diagram illustrating a first embodiment of a method for determining a PRACH transmission beam, and FIG. 8B is a conceptual diagram illustrating a method for determining a PRACH transmission beam according to a second embodiment.
9 is a conceptual diagram illustrating a first embodiment of a method for signaling information on PRACH resource configuration, and FIG. 10 is a conceptual diagram illustrating a second embodiment of a method for signaling information on PRACH resource configuration.
11 is a conceptual diagram illustrating a second embodiment of an initial access method based on uplink beam sweeping, and FIG. 12 is a conceptual diagram illustrating a third embodiment of an initial access method based on uplink beam sweeping.
13 is a conceptual diagram illustrating a second embodiment of a mutual coupling method between downlink resources and uplink resources.
14 is a conceptual diagram illustrating a third embodiment of a mutual coupling method between downlink resources and uplink resources.
15 is a conceptual diagram illustrating a fourth embodiment of a mutual coupling method between downlink resources and uplink resources.
16 is a conceptual diagram illustrating a first embodiment of a mapping method between PRACH resources and transmission beams.
17 is a conceptual diagram illustrating a second embodiment of a mapping method between PRACH resources and transmission beams.
18A is a conceptual diagram illustrating a third embodiment of a mapping method between PRACH resources and transmission beams, FIG. 18B is a conceptual diagram illustrating a fourth embodiment of a mapping method between PRACH resources and transmission beams, and FIG. It is a conceptual diagram illustrating a fifth embodiment of a mapping method between transmission beams.

Since the present invention can make various changes and 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 should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term "and/or" includes any 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, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B”.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

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

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant 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 may be a 4G communication system (eg, a long-term evolution (LTE) communication system, an LTE-A communication system), a 5G communication system (eg, a new radio (NR) communication system), a 6G communication system, and the like. there is. The 4G communication system can support communication in a frequency band of 6 GHz or less, and the 5G communication system can support communication in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. A communication system to which embodiments according to the present invention are applied is not limited to the contents described below, and embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same sense as a communication network, "LTE" may indicate "4G communication system", "LTE communication system" or "LTE-A communication system", and "NR" may indicate "5G communication system" or "NR communication system".

In an embodiment, “setting an operation (eg, transmission operation)” means “setting information for the corresponding operation (eg, information element, parameter)” and/or “performing the corresponding operation”. It may mean that the "instructing information" is signaled. "Setting an information element (eg, parameter)" may mean that a corresponding information element is signaled. "Configuring a resource (eg, a resource region)" may mean that configuration information of a corresponding resource is signaled. Signaling is system information (SI) signaling (eg, transmission of system information block (SIB) and / or master information block (MIB)), RRC signaling (eg, transmission of RRC parameters and / or higher layer parameters) , MAC control element (CE) signaling, or PHY signaling (eg, transmission of downlink control information (DCI), uplink control information (UCI), and/or sidelink control information (SCI)).

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

Referring to FIG. 1, a communication system 100 includes 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 includes a core network (eg, a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), and a mobility management entity (MME)). can include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network includes an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), and the like. can include

The plurality of communication nodes 110 to 130 may support communication protocols (eg, LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.) defined in the 3rd generation partnership project (3GPP) standard. The 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) 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, NOMA (Non-orthogonal Multiple Access) 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 mean an apparatus or a device. Embodiments may be performed by an apparatus or device. The structure of the device (eg, device) may be as follows.

Figure 2 is a block diagram showing a first embodiment of a device.

Referring to FIG. 2 , an apparatus 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 device 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each component included in the device 200 may be connected by a bus 270 to communicate with each other.

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 refer to 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 include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include 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, 120-2), 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. there is. 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), a gNB, an advanced base station (ABS), and a HR -BS (high reliability-base station), BTS (base transceiver station), radio base station, radio transceiver, access point, access node, radio access station (RAS) ), 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, and 130-6 includes user equipment (UE), terminal equipment (TE), advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, mobile 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, and , 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 a corresponding terminal 130-1, 130-2, 130-3, and 130 -4, 130-5, 130-6), and signals received from corresponding terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 are 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 devices (device to device communication, D2D) (or , proximity services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), etc. may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) 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 can transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 uses the SU-MIMO scheme. 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 terminal 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 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 CoMP. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes a terminal 130-1, 130-2, 130-3, and 130-4 belonging to its own cell coverage. , 130-5, 130-6) and a CA method. 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. .

Numerology applied to physical signals and channels in a communication system (eg, NR communication system, 6G communication system) may be variable. The numerology can be varied to meet the various technical requirements of a communication system. In a communication system to which a cyclic prefix (CP) based OFDM waveform technology is applied, the numerology may include a subcarrier interval and a CP length (or CP type). Table 1 may be a first embodiment of a numerology configuration method for a CP-OFDM based communication system. Adjacent subcarrier intervals may have an exponential multiplication of 2 with each other, and the CP length may be scaled by the same ratio as the OFDM symbol length. At least some of the numerologies of Table 1 may be supported according to the frequency band in which the communication system operates. In addition, numerology(s) not listed in Table 1 may be further supported in the communication system. For a specific subcarrier interval (eg, 60 kHz), CP type(s) (eg, extended CP) not listed in Table 1 may be additionally supported.

Table 1 relates to a first embodiment of a numerology configuration method for a CP-OFDM based communication system.

subcarrier spacing 15 kHz 30 kHz 60 kHz 120 kHz 240 kHz 480 kHz OFDM
Symbol length [μs] 66.7 33.3 16.7 8.3 4.2 2.1 CP length [us] 4.76 2.38 1.19 0.60 0.30 0.15 Number of OFDM symbols in 1 ms 14 28 56 112 224 448

Below, the frame structure of the communication system will be explained. Elements constituting a frame structure in the time domain may include subframes, slots, mini-slots, symbols, and the like. A subframe may be used as a unit of transmission or measurement, and the length of a subframe may have a fixed value (eg, 1 ms) regardless of a subcarrier interval. A slot may contain contiguous symbols (eg, 14 OFDM symbols). The length of the slot may be variable, different from the length of the subframe. For example, the length of a slot may be inversely proportional to the subcarrier spacing.

A slot may be used as a unit of transmission, measurement, scheduling, resource configuration, timing (eg, scheduling timing, hybrid automatic repeat request (HARQ) timing, channel state information (CSI) measurement and reporting timing, etc.). The length of an actual time resource used for transmission, measurement, scheduling, resource configuration, etc. may not match the length of a slot. A minislot may contain consecutive symbol(s), and the length of a minislot may be shorter than the length of a slot. A minislot may be used as a unit of transmission, measurement, scheduling, resource configuration, timing, and the like. The mini-slot (eg, the length of the mini-slot, the boundary of the mini-slot, etc.) may be predefined in the technical specification. Alternatively, the mini-slot (eg, mini-slot length, mini-slot boundary, etc.) may be set (or instructed) in the terminal. When a specific condition is satisfied, the use of the mini-slot may be set (or instructed) in the terminal.

The base station may schedule a data channel (eg, physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH), physical sidelink shared channel (PSSCH)) using some or all of the symbols constituting the slot. . In particular, a data channel may be transmitted using a portion of a slot for URLLC transmission, unlicensed band transmission, transmission in a coexistence situation between an NR communication system and an LTE communication system, and multi-user scheduling based on analog beamforming. Also, the base station may schedule a data channel using a plurality of slots. Also, the base station may schedule a data channel using at least one minislot.

Elements constituting the frame structure in the frequency domain may include a resource block (RB), a subcarrier, and the like. One RB may include consecutive subcarriers (eg, 12 subcarriers). The number of subcarriers constituting one RB may be constant regardless of numerology. In this case, the bandwidth occupied by one RB may be proportional to the subcarrier spacing of the numerology. An RB may be used as a unit of transmission and resource allocation of data channels, control channels, and the like. Resource allocation of the data channel may be performed in units of RBs or RB groups (eg, resource block group (RBG)). One RBG may include one or more contiguous RBs. Resource allocation of the control channel may be performed in units of control channel elements (CCEs). In the frequency domain, one CCE may include one or more RBs.

In a communication system, a slot (eg, slot format) is one or more of a downlink (DL) section, a flexible section (or unknown section), and an uplink (UL) section It may consist of a combination of Each of the downlink period, flexible period, and uplink period may consist of one or more consecutive symbols. The flexible period may be located between a downlink period and an uplink period, between a first downlink period and a second downlink period, between a first uplink period and a second uplink period, and the like. When a flexible period is inserted between a downlink period and an uplink period, the flexible period may be used as a guard period.

A slot may contain one or more flexible intervals. Alternatively, a slot may not include a flexible section. The terminal may perform a predefined operation in the flexible period. Alternatively, the terminal may perform semi-static or periodically set operations by the base station in the flexible period. For example, the operations periodically configured by the base station include a physical downlink control channel (PDCCH) monitoring operation, a synchronization signal/physical broadcast channel (SS/PBCH) block reception and measurement operation, and a channel state information-reference signal (CSI-RS) Reception and measurement operation, downlink SPS (semi-persistent scheduling) PDSCH reception operation, SRS (sounding reference signal) transmission operation, PRACH (physical random access channel) transmission operation, and PUCCH (physical uplink control channel) transmission operation configured periodically , a PUSCH transmission operation according to a configured grant, and the like. A flexible symbol may be overridden with a downlink symbol or an uplink symbol. When a flexible symbol is overridden by a downlink or uplink symbol, the terminal can perform a new operation instead of an existing operation in the corresponding flexible symbol (eg, the overridden flexible symbol).

The slot format may be set semi-fixedly by higher layer signaling (eg, radio resource control (RRC) signaling). Information indicating the semi-static slot format may be included in system information, and the semi-static slot format may be set cell-specifically. In addition, the semi-static slot format may be additionally configured for each UE through UE-specific higher layer signaling (eg, RRC signaling). A flexible symbol of a cell-specific slot format may be overridden with a downlink symbol or an uplink symbol by UE-specific higher layer signaling. In addition, the slot format may be dynamically indicated by physical layer signaling (eg, a slot format indicator (SFI) included in downlink control information (DCI)). A slot format set semi-fixedly can be overridden by a dynamically indicated slot format. For example, a semi-fixed flexible symbol may be overridden by a downlink symbol or an uplink symbol by SFI.

The base station and the terminal may perform a downlink operation, an uplink operation, a sidelink operation, and the like in a bandwidth part. The bandwidth portion may be defined as a set of RBs (eg, physical resource blocks (PRBs)) having a specific numerology. RBs constituting one bandwidth portion may be continuous in the frequency domain. One numerology may be used for signal transmission (eg control channel or data channel transmission) in one bandwidth portion. In embodiments, "signal" may refer to any physical signal and channel when used in a broad sense. A terminal performing an initial access procedure may obtain configuration information of an initial bandwidth part from a base station through system information. A UE operating in an RRC connected state may obtain configuration information of a bandwidth part from a base station through UE-specific higher layer signaling.

The setting information of the bandwidth part may include numerology (eg, subcarrier spacing and/or CP length) applied to the bandwidth part. In addition, the setting information of the bandwidth part further includes information indicating the location of the starting RB (eg, starting PRB) of the bandwidth part and information indicating the number of RBs (eg, PRBs) constituting the bandwidth part. can do. At least one bandwidth part among the bandwidth part(s) set in the terminal may be activated. For example, one uplink bandwidth portion and one downlink bandwidth portion may each be activated within one carrier. In a time division duplex (TDD) based communication system, a pair of an uplink bandwidth portion and a downlink bandwidth portion may be activated. The base station can set a plurality of bandwidth parts to the terminal within one carrier, and can switch the active bandwidth part of the terminal.

In embodiments, RB may mean a common RB (CRB). Alternatively, RB may mean PRB or virtual RB (VRB). In a communication system, a CRB may refer to an RB constituting a set of consecutive RBs (eg, a common RB grid) based on a reference frequency (eg, point A). Carriers, bandwidth portions, etc. may be placed on a common RB grid. That is, the carrier, bandwidth portion, etc. may be composed of CRB(s). An RB or CRB constituting the bandwidth portion may be referred to as a PRB, and a CRB index within the bandwidth portion may be appropriately converted to a PRB index. In an embodiment, RB may mean an interlace RB (IRB).

The smallest resource unit constituting the PDCCH may be a resource element group (REG). A REG may consist of one PRB (eg, 12 subcarriers) in the frequency domain and one OFDM symbol in the time domain. Accordingly, one REG may include 12 resource elements (REs). A demodulation reference signal (DM-RS) for decoding (or demodulation) of the PDCCH may be mapped to 3 REs among 12 REs constituting the REG, and control information (eg, modulated DCI) may be It can be mapped to the remaining 9 REs.

One PDCCH candidate may consist of one CCE or aggregated CCEs. One CCE may consist of a plurality of REGs. The NR communication system may support CCE aggregation levels 1, 2, 4, 8, 16, etc., and one CCE may consist of 6 REGs.

A control resource set (CORESET) may be a resource region in which a terminal performs blind decoding (or blind demodulation) of a PDCCH. CORESET may consist of a plurality of REGs. CORESET may consist of one or more PRBs in the frequency domain and one or more symbols (eg, OFDM symbols) in the time domain. Symbols constituting one CORESET may be consecutive in the time domain. PRBs constituting one CORESET may be continuous or discontinuous in the frequency domain. One DCI (eg, one DCI format, one PDCCH) may be transmitted within one CORESET. A plurality of CORESETs may be configured from a cell point of view or a terminal point of view, and the plurality of CORESETs may overlap each other in time-frequency resources.

CORESET may be set in the terminal by PBCH (eg, system information transmitted through PBCH, master information block (MIB)). ID (identifier) of CORESET set by PBCH may be 0. That is, CORESET set by PBCH may be referred to as CORESET #0. A UE operating in an RRC idle state may perform a monitoring operation in CORESET #0 to receive an initial PDCCH in an initial access procedure. Not only a terminal operating in an RRC idle state, but also a terminal operating in an RRC connected state can perform a monitoring operation in CORESET #0. CORESET may be set in the terminal by other system information (eg, system information block type 1 (SIB1)) in addition to system information transmitted through the PBCH. For example, in order to receive a random access response (or Msg2) in a random access procedure, the terminal may receive SIB1 including configuration information of CORESET. In addition, CORESET may be configured in the UE by UE-specific higher layer signaling (eg, RRC signaling).

One or more CORESETs for each downlink bandwidth portion may be configured for the UE. The UE may monitor the PDCCH candidate(s) for the CORESET set in the corresponding bandwidth portion in the downlink active bandwidth portion. Alternatively, the UE may monitor PDCCH candidate(s) for a CORESET (eg, CORESET #0) set in a downlink bandwidth portion other than the corresponding bandwidth portion in the downlink active bandwidth portion. The initial downlink active bandwidth part may include CORESET #0 and may be combined with CORESET #0. CORESET having a quasi co-location (QCL) relationship with the SS/PBCH block in the primary cell (PCell), secondary cell (SCell), and/or primary secondary cell (PSCell) #0 may be set for the terminal. In the secondary cell, CORESET #0 may not be set for the UE.

In this specification, a set of signals including a synchronization signal may be transmitted to the terminal(s), which may be referred to as SSB. Signals constituting the SSB may be predefined in technical specifications. A synchronization signal included in the SSB may be a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and the like. The SSB may further include the aforementioned signals (eg, PBCH, DM-RS for PBCH decoding, CSI-RS, etc.) in addition to the synchronization signal, and may be repeatedly transmitted through a beam sweeping operation. In an NR communication system, SSB may mean SS/PBCH block, and SSB resource may mean SS/PBCH block resource.

A search space may be a set of PDCCH candidate(s) or a set of resource regions occupied by the PDCCH candidate(s). The UE may perform blind decoding on each of the PDCCH candidates within a predefined search space. The UE can determine whether the PDCCH has been transmitted to itself by performing a cyclic redundancy check (CRC) on the blind decoding result. When it is determined that the PDCCH is a PDCCH for the UE, the UE may receive the PDCCH. The terminal may periodically monitor the search space, and may monitor the search space at one or more time positions (eg, PDCCH monitoring location, CORESET) within one period.

The PDCCH candidate may consist of CCE(s) selected by a predefined hash function within a CORESET or search space occasion. The search space may be defined/configured for each CCE aggregation level. In this case, the sum of search spaces for all CCE aggregation levels may be referred to as a search space set. A "search space" may mean a "search space set", and a "search space set" may mean a "search space".

A search space set may be logically associated with or correspond to one CORESET. One CORESET may be logically combined with or correspond to one or more search space sets. A search space set for transmitting a common DCI or a group common DCI may be referred to as a common search space set (hereinafter referred to as "CSS set"). Common DCI or group common DCI may include at least one of resource allocation information of PDSCH for transmission of system information, paging, power control command, SFI, or preemption indicator. In the case of an NR communication system, the common DCI may correspond to DCI formats 0_0, 1_0, etc., system information-radio network temporary identifier (SI-RNTI), paging-RNTI (P-RNTI), random access-RNTI (RA-RNTI) ), TC-RNTI (temporary cell-RNTI), etc., the common DCI cyclic redundancy check (CRC) may be scrambled and transmitted. The group common DCI may correspond to DCI format 2_X (X = 0, 1, 2, ??), etc., and the CRC of the group common DIC may be scrambled and transmitted using slot format indicator-RNTI (SFI-RNTI). CSS sets may include Type 0, Type 0A, Type 1, Type 2, and Type 3 CSS sets.

A search space set for transmitting a UE-specific DCI may be referred to as a UE-specific search space set (hereinafter referred to as a "USS set"). The UE-specific DCI may include scheduling and resource allocation information such as PDSCH, PUSCH, and PSSCH. In the case of an NR communication system, the UE-specific DCI may correspond to DCI formats 0_1, 0_2, 1_1, 1_2, 3_0, 3_1, etc., C-RNTI, CS-RNTI (configured scheduling-RNTI), MCS-C-RNTI ( modulation and coding scheme (C-RNTI), etc., the CRC of the UE-specific DCI may be scrambled and transmitted. Considering scheduling freedom or fallback transmission, a UE-specific DCI may be transmitted even in a CSS set. In this case, the UE-specific DCI may be transmitted according to a DCI format corresponding to the common DCI. For example, the UE can monitor a PDCCH (eg, DCI format 0_0, 0_1) in which a CRC is scrambled with C-RNTI, CS-RNTI, MCS-C-RNTI, etc. in a CSS set.

A type 0 CSS set may be used for reception of DCI scheduling a PDSCH including SIB1 and may be configured through PBCH or cell-specific RRC signaling. The ID of a type 0 CSS set may be given or set to 0. A type 0 CSS set can be logically combined with CORESET #0.

The UE may assume that the PDCCH DM-RS has a QCL relationship with a certain signal (eg, SS/PBCH block, CSI-RS, PDSCH DM-RS, PDCCH DM-RS, etc.). In addition, since the PDCCH has the same antenna port as the PDCCH DM-RS, the PDCCH and the PDCCH DM-RS may have a QCL relationship with each other. Therefore, the UE can obtain information on the large-scale propagation characteristics of the radio channel experienced by the PDCCH and the PDCCH DM-RS through the QCL assumption, and use the information on the large-scale propagation characteristics for channel estimation and reception beam formation. etc. can be used. The QCL parameter is at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial Rx parameter. can include The spatial reception parameter may correspond to at least one characteristic of a reception beam, a reception channel spatial correlation, or a transmission/reception beam pair. For convenience, the spatial reception parameter may be referred to as "spatial QCL". PDCCH may be used in the meaning of including PDCCH DM-RS, and that the PDCCH has a QCL relationship with a certain signal may include the meaning that the DM-RS of the PDCCH has a QCL relationship with the certain signal. A signal or resource having a PDCCH and QCL relationship may be referred to as a QCL source, a QCL source signal, or a QCL source resource.

PDCCHs transmitted in the same CORESET (and corresponding search space set, PDCCH monitoring occasion, etc.) may have the same QCL relationship. That is, an aggregation unit in which the UE assumes the same QCL may be a CORESET, and QCL assumptions in each of the CORESETs may be independent. In an embodiment, QCL, QCL source, etc. of a certain CORESET may mean QCL, QCL source, etc. of a PDCCH received through a corresponding CORESET, respectively. Exceptionally, different QCL assumptions may be applied to search space sets corresponding to one CORESET. For example, a search space set for monitoring RA-RNTI (eg, a type 1 CSS set) and other search space sets may have different QCL relationships.

The QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of CORESET may be determined by a predefined method. For example, in a terminal, a PDCCH DM-RS received through a certain CORESET or a certain search space set is selected in the course of performing an initial access or random access procedure, and a SS/PBCH block and/or CSI-RS and a predefined QCL type It can be assumed to have a QCL relationship for . Here, the QCL type may mean a set of one or more QCL parameter(s). Alternatively, the QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of the CORESET is signaled from the base station to the terminal (eg, RRC signaling, medium access control (MAC) control element (CE) signaling, DCI signaling) , a combination of the above signaling, etc.). That is, the base station may set a transmission configuration information (TCI) state for CORESET in the terminal. In general, a TCI state is an ID of a signal having a QCL relationship with a DM-RS (eg, PDCCH DM-RS) of a physical channel to which TCI is applied (eg, a QCL source and a QCL source resource of PDCCH DM-RS) And / or may include at least one QCL type therefor. For example, the base station may configure one or more TCI state candidates for each CORESET through RRC signaling to the UE, and MAC signaling (or DCI Signaling) can be instructed or set to the terminal. If there is one TCI state candidate configured by RRC signaling, the MAC signaling procedure (or DCI signaling procedure) may be omitted. The terminal may perform PDCCH monitoring and reception operations for the corresponding CORESET based on the TCI state configuration information received from the base station.

Beam operation of a high frequency band and a low frequency band in a communication system may be different from each other. In a low-frequency band (eg, a band of 6 GHz or less), since path loss of a signal due to a channel is relatively small, a signal may be transmitted and received using a beam having a wide beamwidth. In particular, in the case of a control channel, the entire coverage of a cell (or sector) can be covered even with a single beam. However, in a high-frequency band (eg, a band of 6 GHz or higher) in which a signal path loss is large, beamforming using a large-scale antenna may be used to increase a signal reach. In addition, beamforming may be applied not only to data channels but also to common signal and control channels. A communication node (eg, a base station) may form a beam having a small beam width through multiple antennas, and use a plurality of beams having different directivity to cover the entire spatial area of a cell (or sector). Thus, the signal can be transmitted and received multiple times. An operation of repeatedly transmitting a signal on a plurality of time resources using a plurality of beams may be referred to as a beam sweeping operation. A system that transmits a signal using a plurality of beams having a narrow beam width may be referred to as a multi-beam system.

For multi-beam system operation, the base station can manage transmission/reception beams of the terminal. In addition, the UE can manage its transmission/reception beams. The terminal may measure beam quality of a signal (eg, SSB, CSI-RS, etc.) transmitted from a base station or a transmission and reception point (TRP), and may report a beam quality measurement result to the base station. For example, the UE calculates beam quality measurement values such as reference signal received power (RSRP) and signal-to-interference-plus-noise ratio (SINR) for each beam (eg, each signal and each resource). and report the optimal beam(s) and the measurement value(s) corresponding thereto to the base station. The base station may determine a transmission beam for the terminal based on beam quality measurement information received from the terminal. In addition, the base station provides information (e.g., PDCCH, PDSCH, CSI-RS, PUCCH, PUSCH, SRS, PRACH, etc.) For example, QCL information, TCI state information, etc.) may be set in the terminal. In embodiments, unless otherwise specified, “beam” may mean “transmit beam”, “receive beam”, and/or “transmit/receive beam pair”. In addition, "beam", "transmission beam", "reception beam", "transmission/reception beam pair", etc. may have common meanings. Hereinafter, "transmission beam" may correspond to "precoder", "beamformer", "transmission spatial filter", etc., and information about transmission beams may correspond to information about a precoder, beamformer, transmission spatial filter, etc. , transmission spatial relationship information, spatial transmission parameters, and the like. In addition, the "receive beam" may correspond to a "receive filter", a "receive spatial filter", a "receive beamformer", and the like, and the information about the receive beam includes information about the receive filter, the receive spatial filter, the receive beamformer, and the like. It may mean information about QCL, information about QCL type D, reception spatial relationship information, spatial reception parameters, and the like. Also, hereinafter, “multiple beams” may mean at least one beam(s).

3 is a conceptual diagram illustrating a first embodiment of a configuration of a communication network and a signal transmission method based thereon.

Referring to FIG. 3, a base station or serving cell may include one TRP, and downlink and uplink coverage may be formed by the TRP. The terminal may perform both an operation of receiving a downlink signal from the TRP and an operation of transmitting an uplink signal to the TRP. In this case, beamforming may be applied to downlink reception and uplink transmission. For example, the TRP may apply the first beam to transmission/reception of signals with the terminal, and the terminal may apply the second beam to transmission/reception of signals with the TRP (or base station). The transmit beam (or transmit spatial filter) of the terminal may be generated based on the receive beam (or receive spatial filter, beam quality measurement of the received signal) of the terminal. Also, the transmission beam (or transmission spatial filter) of the base station may be generated based on the reception beam (or reception spatial filter, beam quality measurement of the received signal) of the base station. That is, beam correspondence may be established between a transmission beam and a reception beam of a communication node.

A base station (or TRP) may transmit a synchronization signal, broadcast information, and the like to the terminal (s) using multiple beams. For example, one or more resources may be defined or configured for transmission of PSS, SSS, PBCH, SSB, PDCCH, PDSCH, etc., and the signals in the one or more resources may be repeatedly transmitted through a beam sweeping operation. . These signals may be referred to as initial access signals. The terminal may determine a resource for receiving an initial access signal from among the one or more resources and/or a beam corresponding thereto, and may receive an initial access signal from the determined resource (based on the determined beam). For example, the terminal may determine a resource having the largest received signal strength measurement value (eg, RSRP) of the initial access signal as the reception resource, and may determine a beam corresponding thereto as the reception beam of the initial access signal. The terminal may receive an initial access signal and acquire cell ID, downlink timing, broadcast information or system information (eg, MIB, SIB), and the like.

The terminal may perform a random access procedure based on the reception resource and/or beam of the initial access signal.

4 is a conceptual diagram illustrating a first embodiment of an initial access method based on association between downlink resources and uplink resources.

Referring to FIG. 4, downlink resource(s) (eg, downlink resource(s) for initial access) and uplink resources (eg, uplink resource(s) for random access) are can be associated with each other. For example, downlink resource(s) may be SSB transmission resources. Also, the uplink resource(s) may be transmission resources of PRACH. As described above, the base station may repeatedly transmit an initial access signal through multiple beams using downlink resource(s). In this embodiment, the UE is downlink resource #1 (eg, SSB resource #1, CSI-RS resource), which is one of four downlink resources (eg, SSB resources, CSI-RS resources). RS resource #1) may receive an initial access signal (eg, SSB, CSI-RS).

The terminal may receive configuration of the downlink resource(s) and the uplink resource(s) from the base station (eg, receive configuration information of the downlink resource(s) and the uplink resource(s), ), information on a mutual coupling relationship between the uplink resource(s) and the downlink resource(s) may be received. Each of the uplink resource(s) may be combined with one or more downlink resource(s). That is, downlink resource(s) and uplink resource(s) may correspond one-to-one or many-to-one. Alternatively, a plurality of uplink resource(s) may be combined with one downlink resource. That is, downlink resource(s) and uplink resource(s) may correspond one-to-many. Referring to FIG. 4, a UE may be configured with 4 SSB resources and 4 PRACH resources. In addition, a mutual coupling relationship may be established between 4 SSB resources and 4 PRACH resources. For example, SSB resources #0, #1, #2, and #3 may be combined with PRACH resources #0, #1, #2, and #3, respectively.

The UE may transmit the PRACH on uplink resources mutually combined with downlink resources on which the initial access signal is received. Referring to FIG. 4, a UE mutually combines with downlink resource #1 (eg, SSB resource #1, CSI-RS resource #1) having received an initial access signal (eg, SSB or CSI-RS). PRACH can be transmitted on the designated PRACH resource #1. At this time, the transmit beam of the PRACH may be generated based on the receive beam of the initial access signal (eg, SSB or CSI-RS). In addition, resources or beams of other uplink signals for random access (eg, Msg3 PUSCH, MsgA PUSCH, PUCCH including a HARQ response message for Msg4, etc.) It may be determined based on the downlink resource or beam through which the CSI-RS is received (or the uplink resource or beam through which the UE transmits the PRACH). The method described above may be referred to as (method 100).

In this specification, PRACH resources may mean PRACH occasions (or PRACH occasion resources). A random access preamble (or sequence) may be mapped to the PRACH resource one or more times, and the PRACH resource may further include a cyclic prefix (CP) and a guard period. PRACH resources (i.e., PRACH occasions) may include time resources (e.g., symbol(s)) and frequency resources (e.g., RB(s) or subcarrier(s)), code resources or sequences It may further include resources (eg, PRACH sequence(s), PRACH preamble(s)). A PRACH resource may be placed in one or more slot(s) and may include one or more symbol(s). Also, a PRACH resource may include one or more RB(s) or subcarrier(s). Also, multiple PRACH resources (ie, multiple PRACH occasions) may be mapped onto the same time-frequency resource. PRACH resources (ie, PRACH occasions) mapped on the same time-frequency resource may be distinguished by different codes or sequences. One PRACH resource or one PRACH occasion may contain one or more PRACH preamble(s) (or sequence(s). For example, one PRACH resource or one PRACH occasion may have the same time-frequency It may consist of PRACH preamble(s) (or sequence(s)) mapped to a resource. In addition, a plurality of PRACH resources or a plurality of PRACH occasions may have different PRACH preambles (mapped to the same time-frequency resource). s) (or sequence(s)).

Meanwhile, multiple beams may be formed by a plurality of TRPs and/or panels. Hereinafter, TRP and panel may be collectively referred to as TRP. TRPs can be placed based on different spatial locations, antenna shapes, boresight, and the like. Therefore, different beams (eg, a transmission beam, a reception beam, and a transmission/reception beam pair) may be formed in each channel formed between the TRPs and the terminal. The base station can perform multi-beam transmission using multiple TRPs, and transmission reliability can be improved by a beam selection gain or a beam diversity gain. The multiple TRP transmission scheme may be referred to as coordinated multipoint (CoMP). TRPs participating in multiple TRP transmissions may belong to the same base station or the same serving cell. Alternatively, TRPs participating in multiple TRP transmissions may belong to different base stations or different serving cells. As a backhaul environment between TRPs, ideal backhaul and non-ideal backhaul may be considered. It may be difficult to apply joint scheduling between TRPs connected by non-ideal backhaul.

As in the embodiment of FIG. 3, a base station or serving cell may be configured with TRP(s) performing both transmission and reception operations. On the other hand, the base station or serving cell may include at least some TRP(s) that perform only one of a transmission operation and a reception operation. More strictly, a TRP performing only a transmission operation may be referred to as a transmission point (TP), and a TRP performing only a reception operation may be referred to as a reception point (RP). Hereinafter, when the TRP performs only a transmission operation or a reception operation, the TRP may be interpreted as a TP or RP. In the above case, TRP(s) forming downlink coverage and TRP(s) forming uplink coverage may be different from each other, and downlink coverage and uplink coverage may be asymmetrical to each other.

5A and 5B are conceptual diagrams illustrating a configuration of an uplink/downlink asymmetric network using multiple TRPs and a first embodiment of a signal transmission method based thereon.

Referring to Figures 5a and 5b, a base station or a serving cell may include a plurality of TRPs. Among the plurality of TRPs, some TRPs (eg, the first TRPs) may perform both transmission and reception operations, and other TRPs (eg, second to fifth TRPs) may perform only reception operations. can do. Downlink coverage of the base station or serving cell may be formed by the first TRP, and uplink coverage may be formed by the first to fifth TRPs. The terminal may receive a downlink signal from the first TRP and may transmit uplink signals to the first to fifth TRPs.

In the case of downlink transmission, a base station (eg, a first TRP) can transmit a signal using a first beam and a terminal can receive a signal using a second beam. In the case of uplink transmission, the terminal can transmit a signal using the third beam and the base station (eg, the fourth TRP) can receive the signal using the fourth beam. In this case, the transmission beam (or transmission spatial filter) of the terminal may be formed or determined independently of the reception beam (or reception spatial filter, beam quality measurement of the received signal) of the terminal. For example, the third beam, which is the transmission beam of the terminal, may be different from the second beam, which is the reception beam of the terminal. In addition, the transmission beam (or transmission spatial filter) of the base station may be formed or determined independently of the reception beam (or reception spatial filter, beam quality measurement of the received signal) of the base station. For example, a first beam that is a transmission beam of a base station for a terminal may be different from a fourth beam that is a reception beam from the same terminal. Also, a TRP for transmitting a downlink signal and a TRP for receiving an uplink signal may be different from each other. In this way, beam correspondence may not be established between the transmission beam and the reception beam of the communication node.

An initial access procedure of the terminal may be performed based on the above-described uplink and downlink asymmetric networks. In the embodiments of FIGS. 5A and 5B , the terminal may receive a downlink initial access signal from the base station (eg, the first TRP). In addition, the terminal may transmit an uplink signal for random access to the base station. In this case, the random access uplink signal may be received by a TRP (eg, a fourth TRP) different from the first TRP. Also, as described above, a correlation may not exist between the beam of the initial access signal and the beam of the random access uplink signal. Accordingly, it may be difficult for the terminal to select a specific resource or a specific beam to transmit a random access uplink signal.

As a method for solving the above problem, the random access uplink signal may be repeatedly transmitted based on multiple beams. That is, a plurality of (ie, one or more) resources may be defined or configured for the random access uplink signal, and the terminal may repeatedly transmit the random access uplink signal in the plurality of resources. In this case, the same or different beams may be applied to the repeatedly transmitted uplink signals. For example, a random access uplink signal may be beam-sweeped. For example, the random access uplink signal may be PRACH. The base station may configure N PRACH resources for the terminal (N is a natural number), and the terminal may transmit PRACH on M resource(s) among the N PRACH resources (M is a natural number less than or equal to N). In some embodiments, M=N. That is, the terminal can transmit PRACH in all PRACH resources configured by the base station. Repeatedly transmitted PRACHs may be the same signal (eg, a preamble having the same ID, the same sequence). The method described above may be referred to as (Method 110).

In (method 110), transmission beam(s) used for repetitive transmission of a random access uplink signal (eg, PRACH) may be arbitrarily formed or determined by the UE. Simultaneously or separately from this, the transmission beam(s) used for repeated transmission of the random access uplink signal (eg, PRACH) includes at least a portion of the beam(s) used to receive the initial access downlink signal. It may be included or formed based on the beam(s) used to receive the initial access downlink signal.

6 is a conceptual diagram illustrating a first embodiment of an initial access method based on uplink beam sweeping.

Referring to FIG. 6, a UE receives downlink resource(s) (eg, downlink resource(s) for initial access) and uplink resource(s) (eg, uplink for random access) from a base station. resource(s)) can be set. For example, a UE may be configured with 4 SSB resources and 4 PRACH resources (N=4). In the embodiment of FIG. 6, transmission beams #0 to #3 of the base station (eg, the first TRP) may correspond to downlink resources #0 to #3 (or SSB resources #0 to #3). . For example, the base station may transmit SSB resources #0 to #3 based on transmission beams #0 to #3, respectively. Also, reception beams #0 and #1 of the base station (eg, the second TRP) may correspond to uplink resources #0 to #3 (or PRACH resources #0 to #3). For example, the base station (eg, the second TRP) may receive PRACH resources #0 and #1 based on Rx beam #0, and PRACH resources #2 and #3 based on Rx beam #1. can receive

(Method 110) may be applied to this embodiment. That is, the terminal may repeatedly transmit random access uplink signals in uplink resource(s). In this case, the same beam or different beams may be applied to the repeatedly transmitted uplink signals. For example, the UE may repeatedly transmit PRACH in at least some of the 4 PRACH resources. When M=N=4, the UE can repeatedly transmit the PRACH 4 times using all 4 PRACH resources. At this time, the resource (s) through which the UE transmits the PRACH may be determined regardless of the downlink resource through which the UE receives an initial access signal (eg, SSB, CSI-RS). For example, the UE may receive SSB from SSB resource #1. The terminal can determine the resource(s) to transmit the PRACH regardless of the reception resource, and can transmit the PRACH on the determined resource(s). In addition, the PRACH transmission beam may be determined independently of the initial access signal reception beam or arbitrarily by the UE. SSB may be transmitted from the first TRP, and PRACH may be received by the second TRP. As described above, the second TRP may be the same as or different from the first TRP.

In this case, a mutual coupling relationship between downlink resource(s) for initial access and random access uplink resource(s) may be unnecessary. Therefore, when (method 110) is used, downlink resource(s) (eg, downlink resource(s) for initial access, SSB resource(s), CSI-RS resource(s)) and uplink resources (eg, uplink resource (s) for random access, PRACH resource (s)) may not be combined with each other. The terminal may not receive information about the mutual coupling relationship from the base station or may receive information informing that there is no mutual coupling relationship. Alternatively, setting so that there is no coupling relationship between downlink resources and random access uplink resources for repeated transmission as described above means that random access uplink resources for repeated transmission are mutually coupled to each of a plurality of downlink resources (or , associated) may be equivalent to setting it to be. For example, in the above embodiment, the UE may be configured that SSB resources #0 to #3 are correlated with the same PRACH resources, that is, PRACH resources #0 to #3. Based on the configuration, the UE can perform repeated PRACH transmission using the same PRACH resources, that is, PRACH resources #0 to #3 regardless of which SSB resource is determined among SSB resources #0 to #3.

The above-described random access signal transmission method (eg, (method 110)) may or may not be performed depending on circumstances. The base station may instruct the terminal whether to apply the above-described method (eg, (method 110)). When (method 110) is not applied, the terminal may perform a random access operation based on another method (eg, (method 100)). For example, the base station may transmit configuration information indicating whether to apply (method 110) to the terminal. Alternatively, the base station may transmit configuration information instructing the terminal to apply one of (method 100) and (method 110). Configuration information instructed by the base station to the terminal may be determined based on capability information reported by the terminal to the base station. The capability information may include information on whether a repetitive transmission operation of a single-beam and/or multi-beam random access uplink signal (eg, PRACH) is supported. In addition, the configuration information indicated by the base station to the terminal may be determined based on whether beam correspondence (or QCL relationship) is established between SSB reception beam(s) and PRACH transmission beam(s) of the terminal. Information on whether the beam correspondence (or QCL relationship) is established may be included in capability information of the terminal.

In this case, the signaling may be signaling explicitly instructing to apply the above-described method. For example, the configuration information is information indicating that the terminal repeatedly transmits an uplink signal (eg, PRACH), and information indicating that the terminal applies multiple beams to the uplink signal (eg, PRACH). , information instructing the terminal to beam-sweep and transmit an uplink signal (eg, PRACH), and the like. Alternatively, the signaling may be signaling implicitly instructing application of the above-described method. For example, the configuration information includes downlink resource(s) (eg, downlink resource(s) for initial access, SSB resource(s), CSI-RS resource(s)) and uplink resources ( For example, information about a mutual coupling relationship between uplink resource(s) for random access and PRACH resource(s), information indicating to use the mutual coupling relationship, information indicating whether or not the mutual coupling relationship is applied information may be included. The terminal may perform the above-described random access operation based on the information.

As another example of implicit signaling, the base station may inform the terminal of information about M PRACH resource(s) through which the terminal transmits PRACH (eg, M value, location of the M resource(s)). The information may be transmitted to the terminal together with configuration information of N PRACH resource(s). If M=1, the UE may not perform the above-described repeated PRACH transmission operation and may transmit the PRACH based on (method 100). In addition, the UE mutually combines downlink resource (s) (eg, SSB resource (s), CSI-RS resource (s)) and uplink resource (s) (eg, PRACH resource (s)) PRACH can be transmitted using the relationship. On the other hand, if M>1, the UE may perform the above-described repeated PRACH transmission operation and may transmit the PRACH based on (method 110). In addition, the UE mutually combines downlink resource (s) (eg, SSB resource (s), CSI-RS resource (s)) and uplink resource (s) (eg, PRACH resource (s)) PRACH can be transmitted without using a relationship. Alternatively, the UE may repeatedly transmit the PRACH in uplink resources mutually combined with the downlink resources determined by the UE.

The M PRACH resource(s) may be configured from a base station. Alternatively, the M PRACH resource(s) may be determined based on predefined rules. For example, among the N PRACH resource(s), M resource(s) having the lowest index may be determined as the M PRACH resource(s) through which the UE transmits PRACH. The above method may be applied when M<N. Alternatively, the number M of repeated PRACH transmissions may be determined by the UE. In addition, M PRACH resource(s) may be determined by the UE. The UE may arbitrarily select M PRACH resource(s) from among the N PRACH resource(s) configured by the base station, and may transmit PRACH on the selected resources. Simultaneously or separately from this, different M values may be applied for each PRACH resource period. The UE may perform repeated PRACH transmissions at different times within the first PRACH resource period and the second PRACH resource period. Here, the M PRACH resource(s) may be at least some of valid PRACH resources. The validity of PRACH resources will be described later.

Meanwhile, the terminal may receive a downlink signal from the base station after transmitting a random access uplink signal (eg, PRACH). At this time, the terminal can receive the downlink signal based on specific beam(s). When there is no coupling (or association) relationship between an initial access downlink signal (eg, SSB, CSI-RS) and a random access uplink signal (eg, PRACH), or a plurality of initial access downlink resources When correlated with the same random access uplink resource set, it may be difficult for the base station and the terminal to determine specific beam(s) to transmit or receive the downlink signal. Even after successfully detecting a random access uplink signal (eg, PRACH), the base station may still have to repeatedly transmit a downlink signal for the corresponding terminal based on multiple beams in a plurality of downlink resources. .

As a method for solving the above problem, a random access uplink signal combined with (or associated with) each initial access downlink signal (hereinafter referred to as SSB) or each initial access downlink signal resource (hereinafter referred to as SSB resource) Resource(s) (hereinafter referred to as PRACH resource(s)) may be differentiated. In this specification, "SSB" and "SSB resource" may be used interchangeably. For example, a first SSB resource may be combined with a first PRACH resource set, and a second SSB resource may be combined with a second PRACH resource set. When the first SSB resource and the second SSB resource are different from each other, the first PRACH resource set and the second PRACH resource set may be different from each other. Specifically, the first PRACH resource set and the second PRACH resource set may be small to each other. That is, PRACH resources belonging to the first PRACH resource set may not belong to the second PRACH resource set, and PRACH resources belonging to the second PRACH resource set may not belong to the first PRACH resource set.

7 is a conceptual diagram illustrating a first embodiment of a mutual coupling method between downlink resources and uplink resources.

Referring to FIG. 7 , SSB resources configured in the terminal may include four SSB resources, that is, SSB resources #0 to #3. In addition, PRACH resources configured in the terminal may include 16 PRACH resources, that is, PRACH resources #0 to #15. By the above method, different PRACH resource sets can be combined (or associated) with each SSB resource. For example, SSB resource #0 may be combined with PRACH resources #0 to #3, SSB resource #1 may be combined with PRACH resources #4 to #7 other than the PRACH resources, and SSB resource #2 may be combined with PRACH resources #4 to #7. PRACH resources #8 to #11 other than the 8 PRACH resources may be combined, and SSB resource #3 may be combined with PRACH resources #12 to #15 other than the 12 PRACH resources. In the embodiment of FIG. 7 , PRACH resources (or PRACH occasions) may be distinguished by at least one of a time resource, a frequency resource, and a preamble (or sequence). For example, PRACH occasion sets associated with different SSBs may be mapped on different time-frequency resources, and may be mapped to the same PRACH preamble set or to different PRACH preamble sets. Alternatively, PRACH occasion sets associated with different SSBs may be mapped on the same time-frequency resource and may be mapped to different PRACH preamble sets. For example, in the above embodiment, each of PRACH occasions #0 to #3 associated with SSB #0 may be mapped to the same time-frequency resource as each of PRACH occasions #4 to #7 associated with SSB #1; It may be mapped to different sets of PRACH preamble(s). In addition, when different transmission beams are applied to PRACH occasions (eg, each N PRACH occasions or each M PRACH occasions) for which repetitive transmission is performed, the PRACH occasions are at least different from each other. It may be mapped to different time resources (eg, different slots, different symbol sets). For example, PRACH occasions #0 to #3 associated with SSB #0 may be mapped to different slots or different symbol sets.

Also, by the above-described method, each SSB resource may be mutually combined with a plurality of PRACH resources. The UE may repeatedly transmit PRACH in PRACH resources combined with a specific SSB resource. The specific SSB resource may be an SSB resource selected by the terminal in an initial access process, and may be an SSB resource corresponding to an SSB having the largest received signal strength or the highest beam quality. For example, the UE may determine SSB #1 or SSB resource #1 as the optimal SSB. In this case, the terminal may repeatedly transmit the PRACH according to the above-described method using at least a part of PRACH resources combined with SSB resource #1, that is, PRACH resources #4 to #7. That is, the above-described repeated PRACH transmission of the UE may be performed for at least some of the PRACH resources combined with the same SSB resource (eg, SSB determined or selected by the UE).

The base station can successfully detect the PRACH(s) transmitted by the terminal and find out the SSB resource determined by the terminal based on the mutual coupling relationship. For example, the base station may receive the PRACH transmitted by the terminal in at least some of the PRACH resources #4 to #7. In this case, the base station may determine that SSB resource #1, which is an SSB resource combined with PRACH resources #4 to #7, or SSB #1, which is an SSB corresponding thereto, is the SSB determined by the terminal. In addition, after receiving the PRACH, the base station transmits downlink to the terminal based on SSB resource #1 or a beam (or spatial QCL, etc.) used for transmission of SSB resource #1, which is an SSB resource mutually combined with the received PRACH. Signals (eg, Msg2, MsgB, Msg4, PDCCH, PDSCH, CSI-RS, etc.) may be transmitted.

After transmitting the PRACH(s), the UE transmits a downlink signal based on SSB resource #1, which is an SSB resource mutually coupled with the PRACH(s), or a beam (or spatial QCL, etc.) (eg, Msg2, MsgB, Msg4, PDCCH, PDSCH, CSI-RS, etc.) may be received. That is, the UE assumes that the downlink signal or DM-RS for it is QCL (eg, spatial QCL, QCL type D) such as the determined SSB, that is, SSB #1 or a synchronization signal included therein, DM-RS, etc. can The UE may receive the downlink signal in RRC idle mode.

In the above embodiment, the mutual coupling relationship between SSB (or SSB resource) and PRACH (or PRACH resource) is QCL for receiving the downlink signal (eg, PRACH or downlink signal after Msg1 transmission) of the UE. It can be used to determine the relationship (i.e., determine which SSB is the QCL source). For example, the UE transmits an SSB and QCL (eg, spatial QCL), and the PDCCH and/or PDSCH can be received based on the QCL assumption. In addition, the UE may assume that the DM-RS of the PDCCH and/or PDSCH in the RRC connected mode after the random access procedure is completed is QCL with the SSB correlated with the PRACH resource (s) transmitting the PRACH, based on the QCL assumption to receive the PDCCH and/or PDSCH.

In the above embodiment, beam correspondence may not be established between the transmit beam and the receive beam of the UE, and the UE is not based on the mutual coupling relationship between SSB (or SSB resource) and PRACH (or PRACH resource) (UE Arbitrarily) a transmission beam (or transmission spatial relationship information, spatial QCL, etc.) of the PRACH may be determined. Meanwhile, the aforementioned PRACH repeated transmission method can be easily applied to an operating environment in which beam correspondence is established as shown in FIG. 3 . For example, when beam correspondence is established between the transmission beam and the reception beam of the terminal, the terminal may establish a mutual coupling relationship between downlink resources and random access uplink resources as in the above embodiment. The UE may select an SSB resource in the initial access process by the above-described method, and may repeatedly transmit PRACH in PRACH resources mutually combined with the selected SSB resource. However, in this case, the UE may determine the PRACH transmission beam(s) based on the reception beam of the SSB selected based on the beam correspondence.

8A is a conceptual diagram illustrating a first embodiment of a method for determining a PRACH transmission beam, and FIG. 8B is a conceptual diagram illustrating a method for determining a PRACH transmission beam according to a second embodiment.

Referring to FIGS. 8A and 8B , a UE may receive an SSB based on a Rx beam and may repeatedly transmit a PRACH in PRACH resources (or PRACH occasions) correlated with the received SSB. At this time, as described above, the operation of determining the PRACH transmission beam may be determined by whether beam correspondence is established. In the case of FIG. 8A, beam correspondence may not be established between the transmit beam and the receive beam of the UE, and in this case, the UE may determine the PRACH transmit beams based on the correlated SSB receive beams. On the other hand, in the case of FIG. 8B, beam correspondence can be established between the transmission beam and the reception beam of the terminal, and in this case, the terminal can determine the PRACH transmission beams based on the correlated SSB reception beams. For example, each of the PRACH transmit beams may have a QCL (eg, spatial QCL) relationship with a correlated SSB receive beam.

The above-described terminal operations may be selectively applied by the base station. The terminal may receive information indicating whether to apply a mutual coupling relationship with an initial access downlink signal (eg, SSB) to transmission of a random access uplink signal (eg, PRACH) from a base station, and the Based on the indication, a random access uplink signal (eg, PRACH) may be transmitted with or without applying a mutual coupling relationship. Simultaneously or separately from this, the UE determines whether to apply beam correspondence (eg, QCL relationship) with an initial access downlink signal (eg, SSB) to transmission of a random access uplink signal (eg, PRACH). information indicating whether or not to transmit a transmission beam of a random access uplink signal (eg, PRACH) with or without applying beam correspondence (eg, QCL relationship) based on the indication. and may transmit a random access uplink signal (eg, PRACH). The above indication information may be set by higher layer signaling (eg, RRC signaling, SIB, MAC CE, etc.) or indicated by physical layer signaling (eg, DCI).

Meanwhile, a mutual coupling relationship different from that of a UE performing repeated PRACH transmissions may be established for a UE unable to perform the aforementioned repeated PRACH transmission. For example, in the above embodiment, a UE that does not perform repeated PRACH transmission uses four PRACH resources, for example, PRACH resources #0, #4, #8, and #12 (or PRACH resources #0, #5, #10, #15) can be set. PRACH resources #0, #4, #8, and #12 (or PRACH resources #0, #5, #10, and #15) are mutually coupled with SSB resources #0, #1, #2, and #3, respectively. It can be. That is, SSB resources and PRACH resources may correspond one-to-one. When the indexes of PRACH resources are numbered first in the time domain rather than in the frequency domain, the UE assigns the PRACH resources #0, #4, #8, and #12 to PRACH resources #0, #1, #2, and #12, respectively. can be considered as #3. When the index of PRACH resources is numbered first in the frequency domain rather than in the time domain, the UE assigns the PRACH resources #0, #8, #4, and #12 to PRACH resources #0, #1, #2, and #12, respectively. can be considered as #3. The UE may transmit the PRACH on a PRACH resource (eg, PRACH resource #4) combined with the (optimal) SSB resource (eg, SSB resource #1) determined by the UE. In this case, the UE may determine a transmission beam (or transmission spatial relationship information, spatial QCL, etc.) of PRACH based on a mutual coupling relationship between SSB (or SSB resource) and PRACH (or PRACH resource). According to the method described above, the base station can signal different PRACH resource configuration information to a terminal that performs repeated PRACH transmissions and a terminal that does not perform repeated PRACH transmissions. In this case, indexes for the same PRACH resource may be recognized differently by the UEs. The terminal may report information on whether or not it has the ability to perform the above-described repeated PRACH transmission operation to the base station.

In a method different from the above-described method, the base station may signal configuration information about the first PRACH resource set to a terminal not performing repeated PRACH transmissions, and to a terminal performing repeated PRACH transmissions about the first PRACH resource set. In addition to the configuration information, additional information (ie, configuration information on the second PRACH resource set) may be signaled. That is, the terminal can determine the location of the PRACH resources based on the combination of the configuration information for the first PRACH resource set and the configuration information for the second PRACH resource set, and determine the correlation between the PRACH resources and the SSB resources. can decide For example, configuration information on the first PRACH resource set and configuration information on the second PRACH resource set may be included in different RRC messages (eg, different RRC parameters) and transmitted to the UE.

9 is a conceptual diagram illustrating a first embodiment of a method for signaling information on PRACH resource configuration, and FIG. 10 is a conceptual diagram illustrating a second embodiment of a method for signaling information on PRACH resource configuration.

Referring to FIGS. 9 and 10 , a terminal may receive configuration information on a first PRACH resource set from a base station and, in addition, configuration information on a second PRACH resource set. The first PRACH resource set may include 4 PRACH resources, and the second PRACH resource set may include 12 PRCH resources distinct from the 4 PRACH resources. The UE determines the location and SSB resources of PRACH resources #0 to #15 (or PRACH occasions #0 to #15) based on the configuration information on the first PRACH resource set and the configuration information on the second PRACH resource set. interrelationships can be determined. The terminal may be a terminal performing repeated PRACH transmission. According to an embodiment, configuration information on the first PRACH resource set may be transmitted to another terminal (eg, a terminal not performing repeated PRACH transmission), and the other terminal uses the four PRACH resources. A PRACH transmission operation may be performed.

Referring to FIG. 9 , 4 PRACH resources included in the first PRACH resource set and 12 PRACH resources included in the second PRACH resource set may be interlaced in the time domain. At this time, the terminal (ie, the terminal performing the repeated PRACH transmission operation) irrespective of the resource set to which the PRACH resources belong, based on the time-frequency resource positions of the PRACH resources (ie, 16 PRACH resources), the PRACH resource Indexes may be assigned to fields or correlations with SSB resources may be assigned. For example, as shown in FIG. 9 , the terminal may first assign indexes to PRACH occasions mapped to the same frequency domain in ascending order of time resources, and then to the frequency to which the PRACH occasions are mapped. Indexes may be assigned in ascending order of frequency values of regions. Based on the indexing and the number of repeated PRACH transmissions (eg, N = 4 and / or M = 4), the UE maps SSB resources and PRACH as shown in FIG. 9 so that each SSB resource is mapped to four PRACH occasions. Resources can be sequentially mapped to each other in ascending order of index.

Referring to FIG. 10 , 4 PRACH resources included in the first PRACH resource set and 12 PRACH resources included in the second PRACH resource set may not cross each other in the time domain. That is, each of the 4 PRACH resources may be disposed in an earlier section (or earlier or same section) than the 12 PRACH resources. In this case, the terminal may alternately assign indexes to PRACH resources belonging to the first PRACH resource set and PRACH resources belonging to the second PRACH resource set. When the number of PRACH repeated transmissions is 4 (eg, when N=4 and/or M=4), the first PRACH occasion and the second PRACH resource belonging to the first PRACH resource set as shown in FIG. 10 The first three (ie, (N-1)) PRACH occasions belonging to the set may be numbered as PRACH occasions #0 to #3, respectively. Next, the second PRACH occasion belonging to the first PRACH resource set and the next three (ie, (N-1)) PRACH occasions belonging to the second PRACH resource set are PRACH occasions #4 to #7, respectively. can be numbered. The terminal may alternately assign numbers to 16 PRACH occasions included in the first PRACH resource set and the second PRACH resource set by repeatedly applying the above rule. Indexing within each resource set may be performed based on the positional order of time and frequency resources. Based on the indexing and the number of repeated PRACH transmissions (eg, N = 4 and / or M = 4), the UE maps SSB resources and PRACH resources to four PRACH occasions as shown in the figure. can be sequentially mapped to each other in ascending order of index.

According to the method described above, a beam (or QCL, spatial QCL) to be used for downlink signal transmission may be determined after the UE transmits the PRACH based on the mutual coupling relationship between the SSB-PRACH. However, since a plurality of different PRACH resources must be mapped for each SSB according to the above-described method, resource utilization may decrease as a plurality of PRACH resources occupy physical resources.

As a method for solving the above problem, a method of spatially reusing random access uplink resources (eg, PRACH resources) may be considered. The proposed method will be described through examples below.

11 is a conceptual diagram illustrating a second embodiment of an initial access method based on uplink beam sweeping, and FIG. 12 is a conceptual diagram illustrating a third embodiment of an initial access method based on uplink beam sweeping.

Referring to FIGS. 11 and 12 , a base station may include a plurality of TRPs, that is, first, second, and third TRPs. Among them, some TRPs, that is, the second and third TRPs (or RPs) may perform only uplink reception operations. Downlink coverage may be formed by the first TRP, and uplink coverage may be formed by the first, second, and third TRPs. Accordingly, uplink coverage and downlink coverage may be different, and beam correspondence may not be established between the transmission beam and the reception beam as described above.

The first terminal may receive a first downlink signal (eg, a first SSB) and may transmit an uplink signal (eg, PRACH) to perform a random access procedure. In addition, the second terminal may receive a second downlink signal (eg, a second SSB) and may transmit an uplink signal (eg, PRACH) to perform a random access procedure. The first terminal and the second terminal may transmit PRACH on the same PRACH resource(s) (eg, PRACH resource(s) including the first PRACH resource). In this case, according to the proposed method, the PRACH resource(s) may be combined with a plurality of downlink signals (eg, a first SSB and a second SSB).

Referring to FIG. 11 , PRACHs transmitted by UE 1 and UE 2 may be received by the same TRP (eg, second TRP) on the same resource (eg, first PRACH resource). In this case, when the base station receives the PRACH in the first PRACH resource, the terminal transmitting the PRACH combines the first downlink signal (eg, first SSB) and the second downlink signal (eg, SSB) with the PRACH. For example, it may be difficult to know which downlink signal (eg, SSB) was received or determined among the second SSB). Therefore, the base station transmits the transmission beam of the downlink signal (eg, Msg2, MsgB, Msg4, PDCCH, PDSCH, CSI-RS, etc.) to the terminal after transmitting the PRACH (eg, the transmission beam of the base station and/or the transmission beam of the terminal) reception beam) may be difficult to determine, and as a result, transmission of the downlink signal may fail.

On the other hand, referring to FIG. 12 , PRACHs transmitted by UE 1 and UE 2 may be received by different TRPs (eg, the second TRP and the third TRP). In this case, even if the PRACH of the first terminal and the PRACH of the second terminal are received on the same resource (eg, the first PRACH resource), the PRACH of the first terminal and the PRACH of the second terminal are distinguished by the TRP through which the PRACH is received. It can be. That is, when the base station receives the PRACH through the second TRP, it can be determined that the terminal (ie, the first terminal) that transmitted the PRACH received or determined the first downlink signal (eg, the first SSB). there is. In addition, when the base station receives the PRACH through the third TRP, it may be determined that the terminal (ie, the second terminal) that transmitted the PRACH received or determined the second downlink signal (eg, the second SSB). there is. Accordingly, the base station transmits the transmission beam (eg, the transmission beam of the base station and / or the terminal) of the downlink signal (eg, Msg2, MsgB, Msg4, PDCCH, PDSCH, CSI-RS, etc.) to the terminal after transmitting the PRACH. A reception beam of) can be appropriately determined, and the downlink signal can be normally transmitted.

According to the third embodiment of FIG. 12, PRACH resources can be spatially reused. For example, UE 1 belonging to the coverage of the 2nd TRP and UE 2 belonging to the coverage of the 3rd TRP may receive different SSBs or determine the optimal SSB or beam, while using the same PRACH resource(s). A PRACH may be transmitted using a random access procedure, and a random access procedure may be performed. Even if the PRACH resource for which the PRACH is received is the same, UE 1 and UE 2 can be distinguished by the TRPs through which the PRACH is received, and a downlink beam for the UE can be determined. To this end, the same PRACH resource(s) may be combined with (or associated with) a plurality of SSBs. Also, as described above, the UE may be configured with a mutual coupling relationship between SSB-PRACH.

13 is a conceptual diagram illustrating a second embodiment of a mutual coupling method between downlink resources and uplink resources.

Referring to FIG. 13, SSB resources and PRACH resources may be combined, and a plurality of SSBs may be combined in the same PRACH resource set. That is, PRACH resource sets combined to SSBs may be completely identical to each other or may be small sets having no common elements (ie, the intersection is an empty set). Herein, that the first PRACH resource set and the second PRACH resource set coincide with each other means that the PRACH resources belonging to the first PRACH resource set have the same time-frequency resource and the same PRACH preambles as the PRACH resources belonging to the second PRACH resource set, respectively. It can mean made up. In addition, when the first PRACH resource set and the second PRACH resource set are referred to as a small set, the PRACH resources belonging to the first PRACH resource set are mapped to different time-frequency resources from the PRACH resources belonging to the second PRACH resource set. or it may mean that it is composed of different PRACH preambles. For example, a PRACH resource set composed of PRACH resources #0 to #3 may be combined with SSB resource #0 and SSB resource #2. When SSB resource #0 is determined as the optimal SSB and when SSB resource #2 is determined as the optimal SSB, the UE may transmit PRACH in at least some of PRACH resources #0 to #3. The base station may receive the PRACH in at least some of PRACH resources #0 to #3, and based on the TRP having received the PRACH, the terminal transmitting the PRACH determines which SSB among SSB #0 and SSB #2 as the optimal SSB. know what you did

14 is a conceptual diagram illustrating a third embodiment of a mutual coupling method between downlink resources and uplink resources.

Referring to FIG. 14, SSB resources and PRACH resources may be combined, and a plurality of SSBs may be combined with the same PRACH resource. At this time, the PRACH resource sets combined with the SSBs may have some PRACH resource(s) as an intersection set. For example, SSB #0 may be combined with a first PRACH resource set composed of PRACH resources #0 to #3, and SSB #1 may be combined with a second PRACH resource set composed of PRACH resources #2 to #5. there is. The first PRACH resource set and the second PRACH resource set may have an intersection of some PRACH resources, that is, PRACH resources #2 and #3.

As described above, when redundant coupling between SSB resources and PRACH resources is allowed, the number of cases of mutual coupling may increase, and accordingly, signaling overhead for configuring the mutual coupling relationship in the UE may increase. Therefore, an effective signaling method capable of minimizing signaling overhead is required. The proposed method for this will be described through the following examples.

15 is a conceptual diagram illustrating a fourth embodiment of a mutual coupling method between downlink resources and uplink resources.

Referring to FIG. 15, SSB resources and PRACH resources may be combined with each other. At this time, a mutual coupling relationship between SSB resources and PRACH resources may be determined based on an SSB resource index (ie, SSB index) and a PRACH resource index (ie, PRACH occasion index). According to the proposed method, the base station can determine the permutation of the SSB resource index. That is, the SSB resource index may be re-ordered in an order other than ascending or descending order. For example, SSB resource indices may be listed in the order of #0, #4, #1, #5, #2, #6, #3, and #7.

SSB resources whose indices are rearranged may be sequentially mapped with PRACH resources whose indices are arranged in ascending (or descending) order. In this case, the number of PRACH resources mapped to each SSB resource may be referred to as M, and the number of SSBs mapped to each PRACH resource set (ie, the same PRACH resource set) may be referred to as N (M, N is a natural number). When N=1, PRACH resources and SSB resources can be combined without duplication. If N>1, PRACH resources may be redundantly combined with a plurality of SSB resources by the above-described method. According to this embodiment, M = 4 and N = 2 may be. Considering the aforementioned M and N, SSB resources #0, #4, #1, #5, #2, #6, #3, and #7 may be sequentially mapped to PRACH resources #0 to #15. . For example, SSB resources #0 and #4, which are the first N=2 SSB resources, may be equally mapped to PRACH resources #0 to #3, which are the first M=4 PRACH resources, and then N=2 SSB resources. SSB resources #1 and #5, which are resources, can be equally mapped to PRACH resources #4 to #7, which are then M=4 PRACH resources, and then SSB resources #2 and #6, which are N=2 SSB resources. may be equally mapped to PRACH resources #8 to #11, which are then M = 4 PRACH resources, and then SSB resources #3 and #7, which are N = 2 SSB resources, then M = 4 PRACH resources. may be identically mapped to PRACH resources #12 to #15.

In the above method, the permutation of the SSB resource index may be determined by the base station, and configuration information about the permutation of the SSB resource index may be transmitted from the base station to the terminal. In addition, configuration information on SSB resources (eg, number of SSB resources, SSB resource mapping, etc.) and configuration information on PRACH resources (eg, number of PRACH resources or PRACH occasions, PRACH resources or PRACH occasions) configuration, PRACH resource mapping, etc.) may be transmitted from the base station to the terminal. The terminal may receive the configuration information through a signaling procedure (eg, RRC signaling procedure, SIB transmission procedure, DCI, MAC CE, etc.) from the base station. The terminal may determine the correlation between SSB resources and PRACH resources according to the above-described method or a rule corresponding thereto (eg, a predefined rule) based on the SSB resource index order, and based on this, the above-mentioned method One random access operation and subsequent signal transmission/reception operations may be performed. Information on the permutation of the SSB resource index can be expressed by a small number of bit(s), and signaling overhead can be reduced by the above method.

According to another embodiment, the order of PRACH resource indices may be rearranged, and SSB resources sorted in ascending (or descending) indexes may be sequentially mapped with PRACH resources whose indices are rearranged. Likewise, the permutation of the PRACH resource index may be determined by the base station, and information about it may be transmitted from the base station to the terminal. The terminal may determine the correlation between SSB resources and PRACH resources based on the PRACH resource index order, and based on this, may perform the above-described random access operation and subsequent signal transmission/reception operations.

PRACH resources (or PRACH occasions) may include time resources (eg, symbol(s) or slot(s)) and frequency resources (eg, RB(s) or subcarrier(s)). . Also, a PRACH resource (or PRACH occasion) may correspond to one or more PRACH preamble(s) (or sequence(s)). One PRACH resource may be allocated in one slot or in a plurality of contiguous slots. When a plurality of PRACH resources are configured in the UE, the plurality of PRACH resources may have the same resource configuration. That is, the duration and bandwidth of PRACH resources may be the same. PRACH resources may be multiplexed in the frequency domain, multiplexed in the time domain, or multiplexed in the frequency domain and time domain. PRACH resources may be contiguous or discontinuous in the time domain. Also, PRACH resources may appear periodically and repeatedly. In this case, the plurality of PRACH resources may follow the same period and period value, and the plurality of PRACH resources may appear repeatedly for each period. The aforementioned repeated PRACH transmission operation may be performed within one PRACH resource period. That is, the N (or M) PRACH resources for repeated PRACH transmission may be included in the same PRACH resource period. Alternatively, the aforementioned repeated PRACH transmission operation may be performed over a plurality of PRACH resource periods. That is, the N (or M) PRACH resources for repeated PRACH transmission may be mapped over a plurality of PRACH resource periods.

The configuration information may be transmitted to the terminal through a higher layer signaling procedure (eg, RRC signaling procedure, MAC CE signaling procedure). For example, the configuration information may be included in system information (eg, SIB, SIB-1, MIB) and transmitted to the terminal (s), and the terminal may transmit the system information to a random access operation (eg, It can be received before performing PRACH transmission operation). Alternatively, the configuration information may be transmitted to the UE through a physical layer signaling procedure (eg, DCI) or transmitted to the UE through a combination of the signaling procedures.

The transmit power of PRACH may be increased in stages. The UE can expect to receive a random access response from the BS after transmitting the PRACH. For example, the UE can monitor the random access response message in the RAR window period determined according to the PRACH transmission time point. At this time, when the UE does not receive the random access response, the UE may increase transmit power of the PRACH and retransmit the PRACH. The above-described operation may be referred to as power ramping. The UE may increase the power ramping counter for each step of transmitting the PRACH. The transmit power of PRACH may be a function of a power ramping counter. The above-described operation may be repeatedly performed until the terminal receives the RAR response or until the power ramping counter reaches the upper limit value.

, 캐리어

, 서빙 셀

, 및 상향링크 대역폭 부분

에 대한 PRACH의 송신 전력

는 하기 수학식 1에 의해 표현될 수 있다.In the case of the network configuration shown in FIG. 3 or when (method 100) is used, the transmit power of PRACH may be a function of uplink pathloss or an estimated value thereof. For example, transmission

, carrier

, serving cell

, and uplink bandwidth part

Transmit power of PRACH for

Can be expressed by Equation 1 below.

는 단말의 최대 출력 파워일 수 있고,

는 수신 목표 전력일 수 있고,

는 경로 손실일 수 있다. 수신 목표 전력

는 기지국으로부터 설정된 수신 목표 전력값, 파워 램핑 카운터에 의한 전력 증가분, 프리앰블 포맷에 따른 전력 오프셋(또는, 보정값), 2단계 랜덤 액세스를 위한 전력 오프셋(또는, 보정값) 등에 기초하여 결정될 수 있다. 단말은 하향링크 신호의 수신 세기(예를 들어, RSRP)를 측정할 수 있고 이에 기초하여 상향링크 경로 손실을 추정할 수 있다. 이는 상향링크 경로 손실이 하향링크 경로 손실과 유사하다는 전제에 기초할 수 있다. 경로 손실 추정에 사용되는 상기 하향링크 신호는 PRACH와 상호 결합된 신호(예를 들어, PRACH와 상호 결합된 SSB, CSI-RS)일 수 있다.here,

May be the maximum output power of the terminal,

May be the received target power,

may be a path loss. Receive target power

may be determined based on a target reception power value set from the base station, a power increment by a power ramping counter, a power offset (or correction value) according to a preamble format, a power offset (or correction value) for 2-step random access, and the like. . The terminal can measure the reception strength (eg, RSRP) of the downlink signal and can estimate the uplink path loss based on this. This may be based on the premise that uplink path loss is similar to downlink path loss. The downlink signal used for path loss estimation may be a PRACH-intercombined signal (eg, a PRACH-intercombined SSB or CSI-RS).

, 캐리어

, 서빙 셀

, 및 상향링크 대역폭 부분

에 대한 PRACH 송신 전력

는 하기 수학식 2 또는 수학식 3에 의해 결정될 수 있다.On the other hand, in the case of an uplink/downlink asymmetric network as shown in FIGS. 5A and 5B or when (method 110) is used, the node receiving the PRACH and the initial access signal (eg, SSB and CSI combined with the PRACH) -RS) may be different from each other. Therefore, it may be difficult to estimate uplink path loss through the above method. In this case, transmit power of PRACH can be determined regardless of uplink path loss or its estimated value. For example, transmission

, carrier

, serving cell

, and uplink bandwidth part

PRACH transmit power for

Can be determined by Equation 2 or Equation 3 below.

의 값은 기술규격에 미리 정의되거나 기지국으로부터 단말에 설정될 수 있다.

값은 상향링크 경로 손실에 상응하는 값으로 결정될 수 있다. 일 실시예에서,

=0일 수 있다. 이 경우,

은 상향링크 경로 손실을 고려한 보정값으로 결정될 수 있다. here,

The value of may be predefined in the technical standard or set in the terminal from the base station.

The value may be determined as a value corresponding to uplink path loss. In one embodiment,

= 0. in this case,

may be determined as a correction value considering uplink path loss.

Alternatively, PRACH transmission power may be determined by Equation 4 below.

값은 상술한 PRACH 반복 전송 동작의 수행 여부에 의해 결정될 수 있다. 예를 들어, PRACH 반복 전송 동작이 수행되는 경우(예를 들어, (방법 110)이 사용되는 경우)

일 수 있고, PRACH 반복 전송 동작이 수행되지 않는 경우(예를 들어, (방법 110)이 사용되지 않는 경우, 또는 (방법 100)이 사용되는 경우)

일 수 있다. 상술한 PRACH 전력 제어 방법은 (방법 120)으로 지칭될 수 있다.here,

The value may be determined by whether or not the aforementioned repeated PRACH transmission operation is performed. For example, when a PRACH repeated transmission operation is performed (eg, when (method 110) is used)

may be, and the PRACH repeated transmission operation is not performed (eg, when (method 110) is not used or when (method 100) is used)

can be The aforementioned PRACH power control method may be referred to as (method 120).

When the PRACH is repeatedly transmitted, the same transmit power may be applied to the repeatedly transmitted PRACHs. For example, the transmission power value determined by the above method may be equally applied to repeatedly transmitted PRACHs. When the UE does not receive a random access response message in the RAR window after performing repeated PRACH transmission, the UE may increase PRACH transmission power and retransmit repeated PRACH transmission. That is, the UE may transmit a plurality of PRACHs for each power ramping step. At this time, the terminal can execute one power ramping counter, and the one power ramping counter can operate in common for repeatedly transmitted PRACHs. For each power ramping step, the power ramping counter may increase by one. Alternatively, a plurality of power ramping counters may be used for a power ramping operation for repeated PRACH transmissions. For example, the power ramping counter may operate for each repetitively transmitted PRACH, that is, each PRACH resource (or each PRACH occasion). Alternatively, PRACH resources (eg, N PRACH resources or M PRACH resources) for repeated transmission may be distributed to a plurality of PRACH resource groups, and the power ramping counter is for each PRACH resource group It can work.

In a method different from the above-described method, different transmit powers may be applied to repeatedly transmitted PRACHs. For example, the aforementioned PRACH power control method may be independently applied to each PRACH resource configured in the UE or to each PRACH resource group. In this case, one power ramping counter may be commonly applied to a plurality of PRACH resources. Alternatively, the power ramping counter may also operate independently for each PRACH resource or each PRACH resource group.

The UE may check the validity of each of the aforementioned PRACH resources. If the PRACH resource for which the UE transmits the PRACH satisfies a predetermined condition, the UE may consider the PRACH resource to be invalid and may not transmit the PRACH in the PRACH resource. The predetermined conditions may be predefined in technical specifications. For example, when a certain PRACH resource overlaps with a downlink symbol, when it overlaps in time with a specific downlink signal (eg, SSB), and/or when timing conditions with other signals are not satisfied, the PRACH resources may be considered invalid. As an example of the timing condition, a time point at which the terminal receives a PDCCH order (or a DCI corresponding thereto) (eg, the last symbol in which the PDCCH order is transmitted) and a PRACH resource to transmit the PRACH (eg, For example, when the distance (eg, symbol distance) between the first symbols of the PRACH resource is smaller than a reference value, the PRACH resource may be invalid. The above condition may be applied when PRACH transmission is triggered by a PDCCH command.

When performing the above-described repeated PRACH transmission or beam sweeping operation, the UE may transmit the PRACH on available resource(s). In addition, the UE may not transmit PRACH on the non-valid resource(s). Accordingly, the number of PRACH repetitions actually performed by the terminal may be determined for each PRACH resource period or for each power ramping step, and the actual number of PRACH repetitions in a certain period or step is set or a predefined number of repetitions (eg, , N times, or M times). In this case, the PRACH may be transmitted only in some beam directions, and the base station may not receive the PRACH. Therefore, the random access procedure may be delayed.

As a method for solving this problem, the remaining PRACH(s) not transmitted in the ineffective PRACH resource(s) and/or beam(s) corresponding thereto are transferred to other PRACH resource(s) (eg, in the next PRACH resource period). A method of transmitting on the PRACH resource(s) may be considered. At this time, the other PRACH resource(s) (eg, the PRACH resource(s) of the next PRACH resource cycle) and the ineffective PRACH resource(s) may be resources correlated to the same SSB resource(s). . Alternatively, when some PRACH transmissions are dropped by the above-described method in a certain PRACH resource period, the UE may not transmit PRACH in the corresponding period. Instead, the UE may repeatedly transmit PRACH(s) as many as a predetermined or configured number (eg, N or M) in the next PRACH resource period. That is, if all PRACH resources for repeated PRACH transmission are valid, the UE may perform repeated PRACH transmission in the corresponding PRACH period, otherwise, until a PRACH period in which all PRACH resources for repeated PRACH transmission are valid appears. The PRACH transmission operation may be delayed. The UE may perform repeated PRACH transmissions in a certain PRACH period (eg, the earliest PRACH period) in which all PRACH resources for performing the repeated PRACH transmissions are valid among PRACH periods appearing later.

As described above, multiple beams may be applied to PRACH repeated transmission. The UE may determine Tx beams (or Tx spatial filters, Tx spatial relationship information, etc.) to be applied to PRACH resources, and may transmit the PRACH using Tx beams mapped to each resource. At this time, the mapping between PRACH resource(s) and transmission beam(s) (or spatial relationship information(s), transmission spatial correlation parameter(s), spatial QCL(s), etc.) during the same random access procedure is may not change. This may be referred to as (Method 200). Alternatively, mapping between PRACH resource(s) and transmit beam(s) (or spatial relationship information(s), transmit spatial correlation parameter(s), spatial QCL(s), etc.) during the same random access procedure This change may be acceptable. This may be referred to as (Method 210).

16 is a conceptual diagram illustrating a first embodiment of a mapping method between PRACH resources and transmission beams.

Referring to FIG. 16, the PRACH resources configured by the terminal from the base station may include four PRACH resources, that is, PRACH resources #0, #1, #2, and #3. The four PRACH resources may have the same period. The terminal may repeatedly transmit a signal (eg, PRACH) in the four PRACH resources using four transmission beams by the above-described method. At this time, while performing the same random access procedure by (method 200), PRACH resources (or PRACH occasions) and transmission beams (or spatial relationship information, transmission spatial correlation parameters, spatial QCLs, etc.) The mapping between the livers can be maintained. For example, the UE may transmit the PRACH in the first period and the second period within the same random access procedure. For example, the UE may initially transmit the PRACH in the first period, and may retransmit the PRACH after applying power ramping in the second period. In this case, transmission beams #0, #1, #2, and #3 may be mapped to PRACH resources #0, #1, #2, and #3 of the first period, respectively, and the same beam mapping may be performed in the second period. It may be applied to periodic PRACH resources. The UE transmits the same transmission beam (or transmission spatial filter, transmission spatial relationship information) to the same PRACH resources (eg, PRACH resources having the same resource index) of different periods (transmitting PRACH) or different power ramping steps. etc.) can be applied. The above-described operation may be predefined in technical specifications. Alternatively, the terminal may be instructed to perform the above-described operation by the base station.

17 is a conceptual diagram illustrating a second embodiment of a mapping method between PRACH resources and transmission beams.

Referring to FIG. 17 , a UE may receive PRACH resources configured in the same manner as in the first embodiment of FIG. 16 . The terminal may repeatedly transmit a signal (eg, PRACH) using 4 transmission beams according to the above-described method. In this case, mapping of PRACH resources and transmission beams (or spatial relationship information, transmission spatial correlation parameters, spatial QCLs, etc.) may be changed while the UE performs the random access procedure by (method 210). . For example, as described above, the UE may transmit the PRACH in the first period and the second period within the same random access procedure. In this case, transmission beams #0, #1, #2, and #3 may be mapped to PRACH resources #0, #1, #2, and #3 of the first period, respectively, and beam mapping different from this may be performed in the second period. It may be applied to periodic PRACH resources. For example, transmission beams #2, #3, #0, and #1 may be mapped to PRACH resources #0, #1, #2, and #3 of the second period, respectively. The beam mapping change operation may be performed when a predetermined condition is satisfied. For example, when it is determined that at least some of the PRACH resources to be used for repeated PRACH transmissions are invalid resources, the number of valid resource(s) among the PRACH resources to be used for repeated PRACH transmissions is greater than that of the previous period or previous step. When it is changed, the above-described beam mapping change operation may be performed. In this case, an operation of determining a transmission beam (or transmission spatial filter, transmission spatial relationship information, etc.) to be applied to each PRACH resource for which the UE performs repeated PRACH transmission may not be defined in the technical standard. The transmission beam (or transmission spatial filter, transmission spatial relationship information, etc.) applied to the PRACH resource may be arbitrarily or arbitrarily determined by the UE. The terminal may be instructed to perform the above-described operation from the base station.

18A is a conceptual diagram illustrating a third embodiment of a mapping method between PRACH resources and transmission beams, FIG. 18B is a conceptual diagram illustrating a fourth embodiment of a mapping method between PRACH resources and transmission beams, and FIG. It is a conceptual diagram illustrating a fifth embodiment of a mapping method between transmission beams.

Referring to FIGS. 18A to 18C , a UE may be configured with PRACH resources in the same manner as in the above embodiments. The terminal may repeatedly transmit a signal (eg, PRACH) using 4 transmission beams according to the above-described method. At this time, the UE may determine some PRACH resources as invalid resources. For example, in the second period, PRACH resources #0 and #1 may be determined to be invalid resources, and the UE may not transmit PRACH on the corresponding resources. The UE may repeatedly transmit PRACH in at least some of the remaining available PRACH resources (eg, PRACH resources #2 and #3).

In this case, mapping of PRACH resources and transmission beams may be maintained while (method 200) is used and the random access procedure proceeds. Referring to FIG. 18A, transmission beams #2 and #3 may be identically mapped to PRACH resources #2 and #3 in the first period and the second period, respectively. Alternatively, mapping of PRACH resources and transmission beams may be changed while (method 210) is used and the random access procedure is in progress. Referring to FIG. 18B, Tx beams mapped to PRACH resource #2 in the first period and the second period may be different from each other. In this case, the same mapping may be maintained between effective PRACH resource(s) and transmission beam(s). For example, PRACH resource #0 in the first period and PRACH resource #2 in the second period are the first valid PRACH resources in each period, and the same transmission beam, transmission beam #0, is assigned to the first effective PRACH resource in each period. can be mapped. In addition, PRACH resource #1 of the first period and PRACH resource #3 of the second period are the second effective PRACH resources in each period, and the same transmission beam, transmission beam #1, is mapped to the second effective PRACH resource in each period. can Referring to FIG. 18C, Tx beams mapped to PRACH resource #2 in the first period and the second period may be different from each other. The UE may arbitrarily determine transmission beams applied to PRACH resources and transmit the PRACH using the corresponding beams.

In the above embodiments, the UE transmits the PRACH in the first period, but may not receive the RAR for it. In this case, the UE may retransmit the PRACH in the second period. In this case, power ramping may be applied to the PRACH transmitted in the second period. When one power ramping counter is used, the power ramping counter may increase by one for each step regardless of the number of actually transmitted PRACHs (or the number of repetitive PRACH transmissions) in each transmission or retransmission. On the other hand, when a plurality of power ramping counters are used, for example, when the power ramping counter operates for each PRACH resource (or PRACH resource group), the power ramping counter operates in the corresponding PRACH resource (or PRACH resource group). may be counted (ie incremented by 1) only when is actually transmitted. For example, in the third embodiment of FIG. 18A, in the second period, the UE may not count the power ramping counters for PRACH resources #0 and #1, and the power ramping counters for PRACH resources #2 and #3 can be counted. Accordingly, power ramping counters for each PRACH resource may have different values, and accordingly, different transmit powers may be applied to the PRACH resources in each PRACH transmission/retransmission step. According to this, transmission power usage of the UE for PRACH transmission can be reduced.

A base station (or a specific TRP constituting the base station) may receive (or monitor) a PRACH on the PRACH resource(s). Referring back to FIG. 6, the base station can receive (or monitor) PRACH on 4 PRACH resources. For example, the base station may monitor PRACH resources #0 and #1 based on Rx beam #0, and monitor PRACH resources #2 and #3 based on Rx beam #1. For another example, the base station can monitor all PRACH resources based on a single receive beam (eg, a receive beam with omni-directional gain). For another example, the base station may receive (or monitor) a PRACH using four different Rx beams in four PRACH resources. When the base station receives the PRACH from the PRACH resource(s), the base station may inform the terminal of the PRACH resource (eg, PRACH resource index) on which the PRACH was received. If the base station receives a PRACH from a plurality of PRACH resources, the base station can determine one PRACH resource and inform the terminal of the determined PRACH resource (eg, PRACH resource index). Alternatively, the base station may inform the terminal of a plurality of PRACH resources (eg, PRACH resource indexes) upon receiving the PRACH. For example, the base station may inform the terminal of two PRACH resources (eg, two PRACH resource indexes) upon receiving the PRACH. In this case, a beam corresponding to one PRACH resource may be set as a primary beam, and a beam corresponding to another PRACH resource may be set as a secondary beam. The primary beam and the secondary beam may be used for transmission of specific physical signal(s) and/or channel(s), respectively. For example, the primary beam may be used for transmission of PUCCH, SRS, PRACH, MsgA PRACH, MsgA PUSCH, Msg3, PDCCH, CSI-RS, TRS, and the like. The secondary beam may be used for transmission of PUSCH, SRS, PDSCH, CSI-RS, and the like. Alternatively, the base station may notify the terminal of beams corresponding to a plurality of PRACH resources without distinguishing between a primary beam and a secondary beam. In this case, only indexes of a plurality of PRACH resources or information about a combination thereof may be transmitted to the terminal, and signaling overhead may be reduced.

Referring back to FIG. 7 , repeated PRACH transmission may be performed based on a mutual coupling relationship between SSB resources and PRACH resources. For example, the UE may receive SSB resource #1 or an SSB corresponding thereto or determine the optimal SSB, PRACH resources combined with SSB resource #1, that is, PRACH resources #4 to #7 in at least some PRACH resources. can transmit. Through the above-described method, the base station can inform the terminal of the PRACH resource (eg, PRACH resource #5) or its index through which the base station has received the PRACH. In this case, the index may be an indicator (eg, one of values from 0 to 15, that is, 4 bits of information) capable of distinguishing all PRACH resources (eg, PRACH resources #0 to #15). can Alternatively, when the mutual coupling relationship between SSB-PRACH is used as described above, the index is an indicator (eg, 0 to It can be one of values up to 3, that is, 2 bits of information). The partial PRACH resources may be PRACH resources mutually combined with the same SSB resource (eg, SSB resource #1) as the PRACH resource(s) (eg, PRACH resource #5) through which the base station has received the PRACH. The terminal may interpret the index as an index indicating one of the PRACH resources mutually coupled to the same SSB resource as the PRACH resource(s) in which the base station transmits the PRACH, and based on this, the base station transmits the PRACH in a certain PRACH resource. You can see if it has been received. For example, in the above embodiment, when 1 is received among PRACH resource indexes 0 to 3, the UE assumes that the index means PRACH resource #5, which is the second resource among PRACH resources #4 to #7. can be considered According to the latter method, the PRACH resource index can be expressed with fewer bits, and signaling overhead can be reduced.

Information on the PRACH resource determined by the base station (eg, PRACH resource, PRACH resource index, PRACH beam index corresponding to the PRACH resource, etc.) may be included in Msg2 or MsgB and transmitted to the terminal. For example, the information may be included in RAR and may be transmitted through PDSCH. Alternatively, the information may be included in a PDCCH in which a CRC is scrambled with a predetermined RNTI (eg, RA-RNTI), that is, may be transmitted to the terminal as part of a DCI payload. Alternatively, information on the PRACH resource determined by the base station may be included in Msg4 (eg, Msg4 PDSCH) and transmitted to the terminal. By receiving Msg2, MsgB, or Msg4, the UE can know in which PRACH resource(s) the base station successfully received the PRACH. Simultaneously or separately, information on the PRACH resource determined by the base station may be transmitted through a downlink signal or channel transmitted after the terminal receives Msg4. In addition, the terminal can acquire information about the PRACH resource determined by the base station by an implicit method. For example, the terminal can obtain information about the PRACH resource determined by the base station based on the location of the resource where the base station has transmitted a specific signal (eg, PDCCH and/or PDSCH). The terminal assumes that the signal including the information about the PRACH resource has a QCL (eg, spatial QCL) relationship with the SSB correlated with the PRACH resource (s) in which the terminal transmitted the PRACH, and can receive the signal there is. For example, the UE may monitor the PDCCH candidate (s) assuming that the PDCCH candidate (s) has a QCL relationship with the SSB in the type 1 PDCCH CSS set, and Msg2 / MsgB DCI scheduling PDSCH and / or Msg2/MsgB PDSCH can be received.

The UE uses a transmission beam (or transmission spatial filter, transmission spatial relationship information) used for PRACH transmission in the PRACH resource indicated by the base station as a reference beam (or reference transmission spatial filter, reference spatial relationship information) for uplink transmission. can be used as The UE may perform uplink transmission other than the PRACH or uplink transmission after the PRACH by applying the reference beam. For example, the terminal may determine transmission beams such as PUSCH, PUCCH, and SRS based on the transmission beam of the PRACH resource selected by the base station. In addition, the terminal may determine transmission beams such as Msg3 PUSCH, MsgA PUSCH, and Msg4 PDSCH based on the transmission beam of the PRACH resource selected by the base station, and based on the determined transmission beam, Msg3 PUSCH, MsgA PUSCH, Msg4 PDSCH, etc. transmission can be performed. In addition, the terminal may repeatedly transmit Msg3 PUSCH, MsgA PUSCH, etc. in a plurality of PUSCH resources based on configuration information received from the base station. In this case, the same transmission beam (eg, the same transmission beam applied to the PRACH resource indicated by the base station) may be applied to the plurality of resources. In order to continuously manage the reference beam, the above-described operation, that is, the operation in which the UE repeatedly transmits the PRACH and the base station informs the UE of the PRACH resource (eg, PRACH resource index) on which the PRACH is received is repeatedly or periodically can be performed The above-described operation may be performed based on other uplink signals or uplink resources other than PRACH. For example, in the above operation, PRACH may be replaced with SRS, and PRACH resources may be replaced with SRS resources. SRS resource configuration for repeated SRS transmission may be performed based on the aforementioned PRACH resource configuration method. The reference beam management operation by SRS may be applied to a terminal in RRC connected mode. Alternatively, the UE may receive SRS resource configuration information in the RRC idle mode through higher layer signaling (eg, cell-specific RRC signaling, SIB, MIB, etc.) from the base station, and in the RRC idle mode, the SRS resource (s ), repeated SRS transmission can be performed using a plurality of transmission beams.

In the above method, the UE may arbitrarily change or determine the beam of the PRACH. In this case, the reference beam is a beam used in a random access procedure most recently performed by the terminal, a beam applied to a PRACH most recently transmitted by the terminal, and a PRACH transmission most recently performed by the terminal (eg, repeated PRACH transmissions). ) may be determined as a beam corresponding to the PRACH resource indicated by the base station by the above-described method.

The above-described method may be used only when an uplink/downlink asymmetric network and a repeated PRACH transmission method (eg, (method 110)) are applied. In this case, whether or not the PRACH resource information is included in the RAR (or the total payload size of the RAR message) may be determined by whether or not PRACH repeated transmission is performed (or whether the PRACH is indicated). Alternatively, whether the PRACH resource information is included in the payload of a specific DCI format (eg, DCI format in which the CRC is scrambled with RA-RNTI, DCI format 1_0, etc.) depends on whether or not PRACH repeated transmission is performed (or accordingly). instructions). Alternatively, the above-described method may be used regardless of whether or not the UE performs repeated PRACH transmission. Regardless of whether the UE performs repeated PRACH transmission, the base station can inform the UE of information about the PRACH resource on which the UE has successfully received the PRACH through the above-described method.

As described above, the terminal can expect to receive RAR in the RAR window. For example, the terminal may monitor a PDCCH scrambled with a CRC with a specific RNTI (eg, RA-RNTI) in the RAR window, and if reception of the PDCCH is successful, the PDSCH including the corresponding RAR is received can do. In this case, the start time of the RAR window may be determined by the position of the PRACH resource or the PRACH transmission time. For example, the RAR window may start from any one symbol appearing after X symbols from any one symbol (eg, the last symbol) of a reference PRACH resource (or reference PRACH occasion). In an embodiment, X=1 may be. Alternatively, the RAR window is the first CORESET (or search space set, PDCCH monitoring occasion) appearing after X symbols from any one symbol (eg, the last symbol) of the reference PRACH resource (or reference PRACH location). may start from the first symbol of The CORESET (or search space set, PDCCH monitoring occasion) is CORESET (or search space set, PDCCH monitoring occasion ) can be.

The reference PRACH resource (or reference PRACH occasion) for determining the RAR window may be a PRACH resource from which the terminal transmits the PRACH. Meanwhile, when the UE transmits the PRACH in a plurality of PRACH resources according to the above-described method, the reference PRACH resource may be determined as any one resource among the PRACH resources in which the UE transmits the PRACH. Specifically, the reference PRACH resource may be determined as any one of PRACH resources (eg, N PRACH resources or M PRACH resources) for which the UE is configured to perform repeated PRACH transmission. Alternatively, the reference PRACH resource may be determined as one of the PRACH resource(s) in which the terminal actually transmits the PRACH among the configured PRACH resources. For example, the reference PRACH resource may be the latest resource (or the earliest resource) among the PRACH resource(s). Alternatively, the reference PRACH resource is any one resource (eg, the latest resource or the earliest resource) among all PRACH resources (or all available PRACH resources) in the PRACH resource period in which the UE transmits the PRACH. can be determined by

In addition, the value of a specific RNTI (eg, RA-RNTI) used for transmission of the PDCCH and/or PDSCH may be determined by the temporal location of the aforementioned reference PRACH resource (or reference PRACH occasion). For example, the RA-RNTI value may be determined by the index of any one symbol (eg, the first symbol or the last symbol) of the reference PRACH resource determined by the above method.

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

Examples of computer readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the claims below. You will be able to.

Claims (20)

As a method performed by the terminal,
Receiving configuration information of synchronization signal block (SSB) resources from a base station;
Receiving configuration information of physical random access channel (PRACH) resources from the base station;
Receiving an SSB from the base station in a first SSB resource among the SSB resources;
configuring a PRACH resource set associated with the first SSB resource based on configuration information of the PRACH resources; and
Transmitting a first PRACH in a first PRACH resource belonging to the PRACH resource set and transmitting a second PRACH in a second PRACH resource belonging to the PRACH resource set;
The first PRACH and the second PRACH include the same preamble sequence and are transmitted using different beams.
Way. The method of claim 1,
The first PRACH resource and the second PRACH resource are mapped to different time resources,
Way. The method of claim 1,
The beam used for transmission of the first PRACH and the beam used for transmission of the second PRACH are determined without correspondence with a beam used for receiving the SSB by the terminal,
Way. In claim 3,
A transmission and reception point (TRP) transmitting the SSB is the same as or different from a TRP receiving the first PRACH and/or the second PRACH,
Way. The method of claim 1,
The first PRACH resource is further combined with a second SSB resource belonging to the SSB resources,
Way. The method of claim 1,
Further comprising receiving information about an association relationship between the SSB resources and the PRACH resources from the base station,
The PRACH resource set coupled to the first SSB resource is configured based on the information on the association relationship.
Way. The method of claim 1,
The PRACH resource set coupled to the first SSB resource is configured based on an index of the first SSB resource and indexes of PRACH resources belonging to the PRACH resource set.
Way. The method of claim 1,
When the configuration information of the PRACH resources indicates M PRACH resources, the PRACH resource set coupled to the first SSB resource is composed of N PRACH resources, M and N are natural numbers, respectively, and N is M and N respectively. equal or less,
Way. The method of claim 1,
The first PRACH and the second PRACH are transmitted with the same transmission power within the same transmission period or transmitted with different transmission power within the same transmission period.
Way. As a method performed by the base station,
Transmitting configuration information of SSB (synchronization signal block) resources to the terminal;
Transmitting configuration information of physical random access channel (PRACH) resources to the terminal;
Transmitting an SSB in a first SSB resource among the SSB resources; and
Receiving from the terminal a first PRACH in a first PRACH resource belonging to a PRACH resource set associated with the first SSB resource or receiving a second PRACH in a second PRACH resource belonging to the PRACH resource set do,
The first PRACH and the second PRACH include the same preamble sequence and are received using different beams.
Way. The method of claim 10,
The first PRACH resource and the second PRACH resource are mapped to different time resources,
Way. The method of claim 10,
The beam used for receiving the first PRACH and the beam used for receiving the second PRACH do not have correspondence with the beam used for transmitting the SSB.
Way. In claim 12,
A transmission and reception point (TRP) transmitting the SSB is the same as or different from a TRP receiving the first PRACH and/or the second PRACH,
Way. The method of claim 10,
The first PRACH resource is further combined with a second SSB resource belonging to the SSB resources,
Way. The method of claim 10,
Further comprising transmitting information about an association relationship between the SSB resources and the PRACH resources to the terminal,
The PRACH resource set coupled to the first SSB resource is configured based on the information on the association relationship.
Way. The method of claim 10,
The PRACH resource set coupled to the first SSB resource is configured based on an index of the first SSB resource and indexes of PRACH resources belonging to the PRACH resource set.
Way. The method of claim 10,
When the configuration information of the PRACH resources indicates M PRACH resources, the PRACH resource set coupled to the first SSB resource is composed of N PRACH resources, M and N are natural numbers, respectively, and N is M and N respectively. equal or less,
Way. As a terminal,
processor;
instructions executed by the processor; and
a memory for storing the instructions;
When executed by the processor, the instructions cause the terminal to:
Receiving configuration information of synchronization signal block (SSB) resources from a base station;
Receiving configuration information of physical random access channel (PRACH) resources from the base station;
Receiving an SSB from the base station in a first SSB resource among the SSB resources;
configuring a PRACH resource set associated with the first SSB resource based on configuration information of the PRACH resources; and
transmitting a first PRACH in a first PRACH resource belonging to the PRACH resource set and transmitting a second PRACH in a second PRACH resource belonging to the PRACH resource set;
The first PRACH and the second PRACH include the same preamble sequence and are transmitted using different beams.
Terminal. The method of claim 18
The beam used for transmission of the first PRACH and the beam used for transmission of the second PRACH are determined without correspondence with a beam used for receiving the SSB by the terminal,
Terminal. In claim 19,
A transmission and reception point (TRP) transmitting the SSB is the same as or different from a TRP receiving the first PRACH and/or the second PRACH,
Terminal.

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