Method and apparatus for transmitting signal in asymmetric scenario

Abstract

The present invention relates to a signal transmission technique in an asymmetric scenario. According to the present disclosure, a method of a terminal may be provided, the method comprising the steps of: performing downlink synchronization for a first TRP on the basis of a first SSB received from the first TRP; performing downlink synchronization for a second TRP on the basis of a second SSB received from the second TRP; receiving a system information block (SIB) from the first TRP on the basis of the first SSB; and performing a random access procedure with the first TRP and the second TRP.

Description

Method and device for transmitting signals in an asymmetric scenario

[0001] The present disclosure relates to a signal transmission technology in an asymmetric scenario, and more particularly, to a signal transmission technology in an asymmetric scenario that enables uplink transmission capacity to be enhanced in a scenario in which transmission and reception points are arranged asymmetrically.

[0002] Advances in information and communication technology (ICT) can lead to the development of various wireless communication technologies. Representative wireless communication technologies include LTE (long term evolution), NR (new radio), and 6G (6th Generation), all of which are defined by the 3rd Generation Partnership Project (3GPP) standards. LTE can be one of the 4th Generation (4G) wireless communication technologies, and NR can be one of the 5th Generation (5G) wireless communication technologies.

[0003] In order to process the rapidly increasing amount of wireless data following the commercialization of 4G communication systems (e.g., communication systems supporting LTE), 5G communication systems (e.g., communication systems supporting NR) that use a higher frequency band (e.g., a frequency band higher than 6 GHz) than the frequency band of the 4G communication system (e.g., a frequency band below 6 GHz) may be considered. 5G communication systems may support enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and massive Machine Type Communication (mMTC).

[0004] Meanwhile, in a communication system, multiple transmission and reception points (TRPs) and user equipment (UE) can transmit signals isochronously or sequentially. The multiple TRPs may be within the same cell and share the same configuration and resources. Alternatively, the multiple TRPs may be within different cells. The multiple TRPs may transmit signals using different powers. The multiple TRPs may use different powers for uplink and downlink transmissions. In such cases, an initial system access procedure may be required for a terminal to access the TRPs. Furthermore, a method may be required for the terminal to synchronize with the TRPs. Furthermore, a method may be required for the terminal to determine the transmit power during uplink transmission to the TRPs.

[0005] The purpose of the present disclosure to solve the above problems is to provide a method and device for transmitting signals in an asymmetric scenario that can enhance uplink transmission capacity in a scenario where transmission and reception points are arranged asymmetrically.

[0006] In order to achieve the above object, a signal transmission method in an asymmetric scenario according to a first embodiment of the present disclosure may include, as a method of a terminal, the steps of: receiving a first synchronization signal block (SSB) from a first transmission and reception point (TRP); performing downlink synchronization for the first TRP based on the first SSB; receiving a second SSB from a second TRP; performing downlink synchronization for the second TRP based on the second SSB; receiving a system information block (SIB) from the first TRP based on the first SSB; and performing a random access procedure with the first TRP and the second TRP based on the second SSB and / or the SIB.

[0007] Here, the first SSB and the second SSB may include at least one of a first synchronization signal indicating a physical cell identity (PCI) ID (identifier), a second synchronization signal indicating a TRP ID, a third synchronization signal indicating a beam ID, or a physical broadcast channel (PBCH) including a master information block (MIB).

[0008] Here, the first SSB and the second SSB may include at least one of a first synchronization signal indicating a PCI ID, a second synchronization signal indicating a TRP ID, or a PBCH consisting of a beam ID and a master information block.

[0009] Here, the step of receiving a system information block (SIB) from the first TRP based on the first SSB may include the steps of: determining the first TRP as a normal TRP based on the first SSB; obtaining a master information block of the first TRP from the first SSB; and receiving the SIB from the first TRP based on the master information block of the first TRP.

[0010] Here, the step of determining the second TRP as a low-power TRP based on the second SSB is further included, and the terminal may not attempt to obtain a master information block of the second TRP from the second SSB.

[0011] Here, the SIB includes information about first time resource(s) and first frequency resource(s) for transmitting a first preamble from the terminal to the first TRP, the second SSB includes a master information block of the second TRP, and the master information block of the second TRP may include information about second time resource(s) and second frequency resource(s) for transmitting a second preamble from the terminal to the second TRP.

[0012] Here, the step of performing a random access procedure with the first TRP and the second TRP based on the second SSB and the SIB may include the steps of: obtaining information about the first time resource(s) and the first frequency resource(s) from the SIB; obtaining information about the second time resource(s) and the second frequency resource(s) from the second SSB; and performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s).

[0013] Here, the step of performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s) comprises: transmitting the first preamble to a pair of time resources and frequency resources with the first TRP using the first time resource(s) and the second frequency resource(s); transmitting the second preamble to a pair of time resources and frequency resources with the second TRP using the second time resource(s) and the second frequency resource(s); receiving a first signal including a first response to the first preamble and a second response to the second preamble from the first TRP; transmitting a second signal including a terminal identifier to the first TRP; transmitting a third signal including the terminal identifier to the second TRP; and receiving a fourth signal including a third response to the second signal and a fourth response to the third signal from the first TRP.

[0014] Here, the step of performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s) comprises: transmitting the first preamble to the first TRP using one pair of the first time resource(s) and the first frequency resource(s); transmitting the second preamble to the second TRP using one pair of the second time resource(s) and the second frequency resource(s); receiving a first signal including a first response to the first preamble and an instruction for retransmitting the second preamble from the first TRP; retransmitting the second preamble to the second TRP; receiving a second response to the second preamble; transmitting a second signal including a terminal identifier to the first TRP; transmitting a third signal including the terminal identifier to the second TRP; and receiving a fourth signal including a third response to the second signal and a fourth response to the third signal from the first TRP.

[0015] Here, the SIB may include information on the transmission power required to transmit a signal from the terminal to the first TRP.

[0016] Here, the master information block of the second TRP may further include at least one of information indicating the type of TRP, information on a system frame number (SFN), information on a subcarrier spacing (SCS), or information on a transmission power required to transmit a signal from the terminal to the second TRP.

[0017] Here, the method further includes a step of performing uplink synchronization for the first TRP through the random access procedure; and a step of performing uplink synchronization for the second TRP through the random access procedure, wherein the first TRP may be a normal TRP, the first TRP may be a low-power TRP, the first SSB may be a suboptimal SSB, and the second SSB may be a best-effort SSB.

[0018] Meanwhile, in an asymmetric scenario according to a second embodiment of the present disclosure for achieving the above purpose, a signal transmission method may include, as a method of a first transmission and reception point (TRP), a step of transmitting a synchronization signal block (SSB) including at least one of a first synchronization signal for indicating a physical cell identity (PCI) ID (identifier) ​​or a second synchronization signal for indicating a TRP ID to a terminal; a step of transmitting a system information block (SIB) to the terminal based on the SSB; a step of performing a random access procedure with the terminal based on the SIB; and a step of forming a connection state with the terminal.

[0019] Here, the SSB may include at least one of a third synchronization signal or a physical broadcast channel (PBCH) including a master information block (MIB) that allows the terminal to recognize a beam ID.

[0020] Here, when the first synchronization signal and the second synchronization signal are mapped to the same frequency resource and time resource, or when the first synchronization signal and the second synchronization signal are mapped to partially the same frequency resource and time resource, the first synchronization signal and the second synchronization signal can be transmitted by element-wise multiplication or element-wise exclusive-OR.

[0021] Here, the step of performing a random access procedure with the terminal based on the SIB may include: receiving a first preamble from the terminal based on the SIB; receiving a first response to a second preamble transmitted from the terminal to the second TRP from a second TRP; transmitting a first signal including the first response and a second response to the first preamble to the terminal; receiving a second signal including a terminal identifier from the terminal; receiving a third response to the terminal identifier transmitted from the terminal to the second TRP from the second TRP; and transmitting a second signal including the third response and a fourth response to the second signal to the terminal.

[0022] Here, the step of performing a random access procedure with the terminal based on the SIB may include the steps of: receiving a first preamble from the terminal; transmitting a first signal including a first response to the first preamble and an instruction for retransmission of a second preamble to the terminal; receiving a second response to the second preamble from the second TRP; transmitting the second response to the terminal; receiving a second signal including a terminal identifier from the terminal; generating a third response to the second signal; receiving a fourth response to the third signal including the terminal identifier from the second TRP; and transmitting a fourth signal including the third response and the fourth response to the terminal.

[0023] Meanwhile, in an asymmetric scenario according to a third embodiment of the present disclosure for achieving the above object, a signal transmission method may include, as a method of a second transmission and reception point (TRP), a step of transmitting, to the terminal, an SSB (synchronization signal block) including at least one of information on transmission power for transmitting a signal from the terminal to the second TRP or information on time resource(s) and frequency resource(s) for transmitting a preamble from the terminal to the second TRP; a step of receiving the preamble from the terminal based on the time resource(s) and the frequency resource(s); a step of transmitting a first response to the preamble to the first TRP; a step of receiving a terminal identifier from the terminal; and a step of transmitting a second response to the terminal identifier to the first TRP.

[0024] Here, the SSB may include at least one of a first synchronization signal indicating a PCI ID (identifier), a second synchronization signal indicating a TRP ID, a third synchronization signal indicating a beam ID, or a physical broadcast channel (PBCH) including a master information block (MIB).

[0025] Here, the master information block may include at least one of information about the transmission power for transmitting a signal from the terminal to the second TRP or information about the time resource(s) and the frequency resource(s) for transmitting the preamble from the terminal to the second TRP.

[0026] According to the present disclosure, a transmission / reception procedure can be provided that maximizes the uplink transmission capacity of a terminal in an asymmetric scenario. Specifically, in an asymmetric scenario, the terminal can determine the uplink transmission power to a low-power transceiver point. Furthermore, since the transceiver point that manages the low-power transceiver point can instruct the terminal on an appropriate uplink transmission power, the problem of interference with adjacent cells caused by excessive uplink transmission power to the low-power transceiver point can be resolved. Furthermore, the problem of the terminal becoming desynchronized with the low-power transceiver point can be resolved.

[0027] Figure 1 is a conceptual diagram illustrating a first embodiment of a communication system.

[0028] Figure 2 is a block diagram illustrating a first embodiment of a communication node constituting a communication system.

[0029] Figure 3a is a conceptual diagram illustrating embodiments of a communication system having multiple transmitting and receiving points.

[0030] FIG. 3b is a conceptual diagram illustrating embodiments of a communication system having multiple transmitting and receiving points.

[0031] Figure 4 is a conceptual diagram for explaining signal transmission between transmission and reception points and terminals in an asymmetric scenario.

[0032] Figure 5a is a conceptual diagram for explaining signal transmission between transmission and reception points and terminals in an asymmetric scenario.

[0033] Figure 5b is a timing diagram for explaining the transmission and reception times of signals between a terminal and a transceiver point in an asymmetric scenario.

[0034] Figure 6 is a flowchart illustrating embodiments of an initial system connection setup method.

[0035] Figures 7a to 7d are conceptual diagrams illustrating embodiments of random access channel occasions.

[0036] Figure 8 is a flowchart illustrating embodiments of an initial random access setup method.

[0037] Figure 9 is a flowchart illustrating embodiments of an initial random access setup method.

[0038] This disclosure may be subject to various modifications and various embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the disclosure to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the disclosure.

[0039] While terms such as "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present disclosure, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component." The term "and / or" includes a combination of multiple related items described herein or any of multiple related items described herein.

[0040] In embodiments of the present disclosure, “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.” Furthermore, in embodiments of the present disclosure, “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.”

[0041] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0042] The terminology used in this disclosure is only used to describe specific embodiments and is not intended to limit the present disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0043] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this disclosure pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0044] A communication system to which embodiments according to the present disclosure are applied will be described. The communication system to which embodiments according to the present disclosure are applied is not limited to the scope described below, and embodiments according to the present disclosure can be applied to various communication systems. Here, the term "communication system" may be used interchangeably with "communication network."

[0045] Throughout the specification, the network may include, for example, wireless internet such as WiFi (wireless fidelity), mobile internet such as WiBro (wireless broadband internet) or WiMax (world interoperability for microwave access), 2G mobile communication networks such as GSM (global system for mobile communication) or CDMA (code division multiple access), 3G mobile communication networks such as WCDMA (wideband code division multiple access) or CDMA2000, 3.5G mobile communication networks such as HSDPA (high speed downlink packet access) or HSUPA (high speed uplink packet access), 4G mobile communication networks such as LTE (long term evolution) or LTE-Advanced, and 5G mobile communication networks.

[0046] Throughout the specification, a terminal may refer to a mobile station, a mobile terminal, a subscriber station, a portable subscriber station, a user equipment, an access terminal, etc., and may include all or part of the functions of a terminal, a mobile station, a mobile terminal, a subscriber station, a portable subscriber station, a user equipment, an access terminal, etc.

[0047] Here, a desktop computer, laptop computer, tablet PC, wireless phone, mobile phone, smart phone, smart watch, smart glass, e-book reader, portable multimedia player (PMP), portable game console, navigation device, digital camera, digital multimedia broadcasting (DMB) player, digital audio recorder, digital audio player, digital picture recorder, digital picture player, digital video recorder, digital video player, etc. capable of communicating with the terminal can be used.

[0048] Throughout the specification, a base station may also refer to an access point, a radio access station, a node B, an evolved node B, a base transceiver station, a mobile multihop relay (MMR)-BS, etc., and may include all or part of the functions of a base station, an access point, a radio access station, a node B, an eNodeB, a base transceiver station, an MMR-BS, etc.

[0049] Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the attached drawings. In order to facilitate an overall understanding in describing the present disclosure, identical reference numerals will be used for identical components in the drawings, and redundant descriptions of identical components will be omitted.

[0050] Figure 1 is a conceptual diagram illustrating a first embodiment of a communication system.

[0051] Referring to FIG. 1, a communication system (100) may include 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). Here, the communication system may be referred to as a "communication network." Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may support a communication protocol based on CDMA (code division multiple access), a communication protocol based on WCDMA (wideband CDMA), a communication protocol based on TDMA (time division multiple access), a communication protocol based on FDMA (frequency division multiple access), a communication protocol based on OFDM (orthogonal frequency division multiplexing), a communication protocol based on OFDMA (orthogonal frequency division multiple access), a communication protocol based on SC (single carrier)-FDMA, a communication protocol based on NOMA (non-orthogonal multiple access), a communication protocol based on SDMA (space division multiple access), etc. Each of the plurality of communication nodes may have the following structure.

[0052] Figure 2 is a block diagram illustrating a first embodiment of a communication node constituting a communication system.

[0053] Referring to FIG. 2, a communication node (200) may include at least one processor (210), a memory (220), and a transceiver (230) that is connected to a network and performs communication. In addition, the communication node (200) may further include an input interface device (240), an output interface device (250), a storage device (260), etc. Each component included in the communication node (200) may be connected by a bus (270) to perform communication with each other. However, each component included in the communication node (200) may be connected through an individual interface or an individual bus centered around the processor (210), rather than a common bus (270). For example, the processor (210) may be connected to at least one of the memory (220), the transceiver (230), the input interface device (240), the output interface device (250), and the storage device (260) through a dedicated interface.

[0054] The processor (210) can execute program commands 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 in which methods according to embodiments of the present invention are performed. Each of the memory (220) and the storage device (260) may be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (220) may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0055] Referring again to FIG. 1, the communication system (100) may include a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) and a plurality of user equipment (UEs) (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 UE (130-3), and the fourth UE (130-4) may be within the coverage of the first base station (110-1). The second UE (130-2), the fourth UE (130-4), and the fifth UE (130-5) may be within the coverage of the second base station (110-2). The fifth base station (120-2), the fourth UE (130-4), the fifth UE (130-5), and the sixth UE (130-6) may be within the coverage of the third base station (110-3). The first UE (130-1) may be within the coverage of the fourth base station (120-1). The sixth UE (130-6) may be within the coverage of the fifth base station (120-2).

[0056] Here, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be referred to as a NodeB, an evolved NodeB, a BTS (base transceiver station), a radio base station, a radio transceiver, an access point, an access node, a road side unit (RSU), a DU (digital unit), a CDU (cloud digital unit), a RRH (radio remote head), a RU (radio unit), a TP (transmission point), a TRP (transmission and reception point), a relay node, etc. Each of the plurality of UEs (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) may be referred to as a terminal, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, etc.

[0057] Each of the 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) can support cellular communication (e.g., long term evolution (LTE), LTE-A (advanced) as defined in the 3rd generation partnership project (3GPP) standard). Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can operate in a different frequency band or can operate in the same frequency band. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can be connected to each other via an ideal backhaul or a non-ideal backhaul, and can exchange information with each other via the ideal backhaul or the non-ideal backhaul. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can be connected to a core network (not shown) via an ideal backhaul or a non-ideal backhaul. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit a signal received from the core network to the corresponding UE (130-1, 130-2, 130-3, 130-4, 130-5, 130-6), and can transmit a signal received from the corresponding UE (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) to the core network.

[0058] Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can support OFDMA-based downlink transmission and SC-FDMA-based uplink transmission. In addition, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can support MIMO (multiple input multiple output) transmission (e.g., single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) transmission, carrier aggregation transmission, transmission in an unlicensed band, device to device (D2D) communication (or, ProSe (proximity services), etc.). Here, each of the plurality of UEs (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) can support the base station (110-1, 110-2, 110-3, 120-1, 120-2) and can perform operations supported by base stations (110-1, 110-2, 110-3, 120-1, 120-2).

[0059] Meanwhile, in a communication system, a base station can perform all functions of a communication protocol (e.g., remote radio transmission / reception function, baseband processing function). Alternatively, among all functions of the communication protocol, the remote radio transmission / reception function can be performed by a transmission reception point (TRP) (e.g., f(flexible)-TRP), and among all functions of the communication protocol, the baseband processing function can be performed by a baseband unit (BBU) block. The TRP can be a remote radio head (RRH), a radio unit (RU), a transmission point (TP), etc. The BBU block can include at least one BBU or at least one digital unit (DU). The BBU block can be referred to as a "BBU pool", a "centralized BBU", etc. The TRP can be connected to the BBU block via a wired fronthaul link or a wireless fronthaul link. A communication system consisting of a backhaul link and a fronthaul link may be as follows. When a function split method of the communication protocol is applied, the TRP may selectively perform some functions of the BBU or some functions of the MAC (medium access control) / RLC (radio link control).

[0060] In the present disclosure described below, a node communicating with a base station or a transmission / reception point (TRP) may be referred to as a user equipment (UE) (i.e., a terminal). The TRP may be controlled by a base station (BS). The UE, BS, and / or TRP may include at least some of the configurations of FIG. 2 described above, and may further have additional configurations. For example, the UE may further include various interfaces and / or sensors for user convenience. The BS may further include an interface (e.g., a backhaul interface and / or a fronthaul interface) for communicating with the TRP, other BSs, and / or a specific network function (NF) of the core network. The TRP may further include an interface for communicating with the BS. However, it should be noted that this is for convenience of description and is not limited thereto. All possible configurations read by the concept of the method, procedure, and device according to the present disclosure may be included in the scope of the present disclosure. Multiple TRPs and terminals can transmit signals isochronously or sequentially.

[0061] FIG. 3a is a conceptual diagram illustrating embodiments of a communication system having multiple transmitting and receiving points.

[0062] Referring to Figure 3a, a terminal may reside within a serving cell having an arbitrary physical cell identity (PCI). Two TRPs (TRP 1 and TRP 2) with the same PCI may exist within the serving cell. Such a communication system may be referred to as an intra-cell multi-TRP (M-TRP or MTRP) communication system. The serving cell has two TRPs, but may include more TRPs.

[0063] FIG. 3b is a conceptual diagram illustrating embodiments of a communication system having multiple transmitting and receiving points.

[0064] Referring to FIG. 3b, a terminal may exist within a serving cell having any PCI. One or more TRPs (TRP 1) having the same PCI may exist within the serving cell. A TRP (TRP 2) having a different PCI from that of the serving cell may exist in an area adjacent to the serving cell. Such a communication system may be referred to as an inter-cell M-TRP communication system. The serving cell has two TRPs, but may include more TRPs. An intra-cell M-TRP-based or inter-cell M-TRP-based communication system may support downlink and uplink transmission. The downlink may be a link from a TRP to a terminal. The uplink may be a link from a terminal to a TRP.

[0065] Figure 4 is a conceptual diagram for explaining signal transmission between transmission and reception points and terminals in an asymmetric scenario.

[0066] Referring to FIG. 4, a base station (441) can communicate with a terminal (411) located within its cell using multiple TRPs (401, 402, 403). To simplify the drawing, only three TRPs (401, 402, 403) are illustrated. The number of TRPs that can be included in a base station (441) may not be limited to three. A base station (441) may include only one TRP, two TRPs, or four or more TRPs. Since the present disclosure describes an mTRP environment, a case in which a base station (441) includes only one TRP may not be considered.

[0067] It can be assumed that three different TRPs are included in one base station (441). A first TRP (401) may have a first cell area (410), a second TRP (402) may have a second cell area (420), and a third TRP (403) may have a third cell area (430). The first cell area (410) formed by the first TRP (401) may be a cell having the widest area, and the first cell area (410) may overlap with the second cell area (420) and the third cell area (430). The second cell area (420) formed by the second TRP (402) may be included in the first cell area (410), and the third cell area (430) formed by the third TRP (403) may be included in the first cell area (410).

[0068] The transmission distance of a signal, or in other words, the cell area, can be inversely proportional to the square of the distance. If they have the same transmission power, the signal cell areas can have the same size. Based on this, it can be seen from the configuration of the cell areas (410, 420, 430) that the second TRP (402) and the third TRP (403) are low power TRPs (LPTs) compared to the first TRP (401). A case where a part of the second cell area (420) overlaps a part of the third cell area (430) is exemplified. However, the second cell area (420) and the third cell area (430) may not overlap each other.

[0069] The first TRP (401) can perform downlink (DL) and uplink (UL) transmission with the terminal (411), and the second TRP (402) and / or the third TRP (403) can also perform downlink and uplink transmission with the terminal (411). The terminal (411) is exemplified as being located outside the second cell (420) set by the second TRP (402), but this is due to the constraints of the drawing, and in the following description, it can be assumed that the terminal (411) is located within the second cell (420). The terminal (411) is exemplified as being located outside the third cell (430) set by the third TRP (403), but this is due to the constraints of the drawing, and in the following description, it can be assumed that the terminal (411) is located within the third cell (430). The downlink transmission from the second TRP (402) to the terminal (411) may be a "minimum transmission", and the downlink transmission from the third TRP (403) to the terminal (411) may also be a "minimum transmission". "Minimum transmission" may mean that a very small amount of data (or signal) including control information is transmitted.

[0070] The uplink transmission from the terminal (411) to the second TRP (402) may be a "maximum transmission," and the uplink transmission from the terminal (411) to the third TRP (403) may also be a "maximum transmission." "Maximum transmission" may mean that a very large amount of data (or signal) including control information is transmitted. The maximum transmission may mean that most of the data (or signal) is transmitted.

[0071] It may be noted that the downlink transmission from the first TRP (401) to the terminal (411) is unmarked. The downlink transmission from the first TRP (401) to the terminal (411) without any marking may mean transmission in accordance with the communication standards. The downlink transmission from the first TRP (401) to the terminal (411) may mean that all control information as well as data can be transmitted via the downlink. Similarly, it may be noted that the uplink transmission from the terminal (411) to the first TRP (401) is unmarked. The uplink transmission from the terminal (411) to the first TRP (401) without any marking may mean transmission in accordance with the communication standards. The uplink transmission from the terminal (411) to the first TRP (401) may mean that all control information as well as data can be transmitted via the uplink.

[0072] When three different TRPs (401, 402, 403) are configured within a base station (441), transmission of downlink data to a terminal (411) may be performed primarily in the first TRP (401). On the other hand, when three different TRPs (401, 402, 403) are configured within a base station (441), uplink data transmitted by a terminal (411) may be transmitted primarily to a second TRP (402) and / or a third TRP (403). This is because transmitting data through the closest one TRP or the closest two TRPs can reduce transmission power consumption of the terminal (411). Therefore, the terminal (411) may transmit data through the uplink to the second TRP (402) and / or the uplink to the third TRP (403).

[0073] A scenario in which uplink and downlink data are transmitted via different TRPs may be referred to as an "asymmetric mTRP scenario" or "asymmetric scenario" in the following description. On the other hand, the mTRP scenario illustrated in FIGS. 3A and 3B described above, in which uplink and downlink transmissions are performed via a single TRP, may be referred to as a "symmetric mTRP scenario" or "symmetric scenario."

[0074] In the case of an asymmetric scenario, the current standard does not specify how the terminal (411) performs the initial system connection. In addition, in the case of an asymmetric scenario, the current standard does not specify the uplink synchronization method between the terminal (411) and each of the low-power TRPs (402, 403). Furthermore, in the case of an asymmetric scenario, the current standard does not specify the procedure for determining the uplink transmission power of the terminal (411) or the uplink data transmission. Therefore, in the asymmetric scenario, an initial connection method, an uplink synchronization method, an uplink power determination method, and a method for performing uplink data transmission may be required.

[0075] In this disclosure, a wireless device may be referred to as a mobile station (MS). A TRP may refer to a device that transmits signals to or receives signals from an MS. A base station may be a device that manages a TRP. The area managed by a BS may be referred to as a cell. An MS may be referred to as a UE or terminal.

[0076] Figure 5a is a conceptual diagram for explaining signal transmission between transmission and reception points and terminals in an asymmetric scenario.

[0077] Referring to FIG. 5A, a base station (541) can be connected to a first TRP (501), a second TRP (502), and a third TRP (503), and can communicate with a terminal (511) through the TRPs (501, 502, 503). The base station (541) can directly control the first TRP (501), the second TRP (502), and the third TRP (503) or indirectly through other TRPs. The first TRP (501) can perform downlink and / or uplink transmission with the terminal(s) within the first cell (510) established by the first TRP (501). The second TRP (502) can perform downlink and / or uplink transmission with terminal(s) within the second cell (520) established by the second TRP (502), and the third TRP (503) can also perform downlink and / or uplink transmission with terminal(s) within the third cell (530) established by the third TRP (503).

[0078] Although the terminal (511) is exemplified as being located outside the second cell (520) set by the second TRP (502), this is due to the limitations of the drawing, and in the following description, it can be assumed that the terminal (511) is located within the second cell (520). Although the terminal (511) is exemplified as being located outside the third cell (530) set by the third TRP (503), this is due to the limitations of the drawing, and in the following description, it can be assumed that the terminal (511) is located within the third cell (530).

[0079] The first TRP (501) may be a TRP capable of downlink (DL) and uplink (UL) transmission. The first TRP (501) may be referred to as a "head TRP," a "macro TRP," or a "normal power TRP (NPT)." The second TRP (502) and / or the third TRP (503) may be referred to as "low power TRPs (LPTs)" and may transmit only control information limited to the downlink. Each of the second TRP (502) and / or the third TRP (503) may transmit (or broadcast) synchronization signal blocks (SSBs) within its own cell area (520, 530). The first TRP (501), the second TRP (502), and the third TRP (503) may all use different PCIs. In contrast, the first TRP (501), the second TRP (502), and the third TRP (503) can all use the same PCI.

[0080] According to one of the methods presented in the current 3GPP Rel-19 work item description (WID), a method for reducing the downlink transmission of LPTs has been proposed as an option to further reduce energy consumption. Therefore, in an asymmetric scenario, the second TRP (502) and / or the third TRP (503) can transmit only the synchronization signal block(s) as one method for reducing the downlink transmission.

[0081] Since the second TRP (502) and the third TRP (503) are both located within the first cell area (510) of the first TRP (501), it can be understood that the first TRP (501) controls them. In an asymmetric scenario, each of the second TRP (502) and the third TRP (503) can save energy by transmitting only SSB(s) to the terminal (511). At this time, since the second TRP (502) and the third TRP (503) are both LPTs, the second TRP (502) and the third TRP (503) can transmit SSBs that do not include a physical broadcast channel (PBCH) to the terminal (511) to further reduce power consumption. The terminal can receive SSBs that do not include a physical broadcast channel from the second TRP (502) and the third TRP (503). In other words, since both the second TRP (502) and the third TRP (503) are LPTs, the second TRP (502) and the third TRP (503) can transmit SSBs that do not include MIB to the terminal (511) to further reduce power consumption. The terminal can receive SSBs that do not include MIB from the second TRP (502) and the third TRP (503).

[0082] Figure 5b is a timing diagram for explaining the transmission and reception times of signals between a terminal and a transceiver point in an asymmetric scenario.

[0083] Referring to FIG. 5B, T00 may denote an assumed transmission time point from the UE. In addition, T04 may denote an Rx time point from the first TRP (501) to the UE. Accordingly, the time duration from T00 to T04 may be a round-trip delay between the first TRP (501) and the UE (511). In other words, it may be a time delay from when the first TRP (501) transmits a signal to the UE (511), to when the UE (511) receives the signal, and then when the UE (511) transmits the signal to the first TRP (501) and receives the signal at the first TRP (501).

[0084] T01 may be an example assuming a reception time point (RX time point out of synchronization from UE to third TRP) from the terminal (511) to the third TRP (503) in an asynchronous state, and T02 may be an example assuming a reception time point (RX time point within synchronization from UE to second TRP) from the terminal (511) to the second TRP (502) in a synchronized state. T03 may be an example assuming Tx / Rx time points from / to all of TRPs (first TRP, second TRP and third TRP).

[0085] In an asymmetric scenario, the second TRP (502) and the third TRP (503) can save energy by transmitting only SSBs to the terminal (511). In this way, if the second TRP (502) and the third TRP (503) each transmit only SSB(s) to the terminal (511), inefficient decoding and new MIB regulation issues may arise.

[0086] Referring back to FIG. 5A, the terminal (511) may be closer to the third TRP (503) than to the first TRP (501) and the second TRP (502). When the terminal (511) attempts an initial connection, the terminal (511) may receive an SSB from each of the first TRP (501), the second TRP (502), and the third TRP (503). The terminal (511) may select the SSB received from the third TRP (503), which is closest to the terminal (511), as the optimal SSB among the SSBs received from each of the first TRP (501), the second TRP (502), and the third TRP (503). In this case, both the second TRP (502) and the third TRP (503) may be LPTs. In order to further reduce power consumption, the second TRP (502) and the third TRP (503) may transmit an SSB that does not include a PBCH to the terminal (511). When the second TRP (502) and the third TRP (503), which are LPTs, transmit an SSB that does not include a PBCH to the terminal (511), the following problems may occur. In other words, in order to further reduce power consumption, the second TRP (502) and the third TRP (503), which are LPTs, may transmit an SSB that does not include a MIB to the terminal (511). When the second TRP (502) and the third TRP (503), which are LPTs, transmit an SSB that does not include a MIB to the terminal (511), the following problems may occur.

[0087] The terminal (511) can select an optimal SSB from among the SSBs received from each of the TRPs to obtain initial synchronization, and can decode the selected optimal SSB. If the terminal (511) selects the SSB received from the third TRP (503) as the optimal SSB, the terminal (511) can decode the SSB received from the third TRP (503). Since the third TRP (503) transmits an SSB that does not include a PBCH (or MIB), the terminal (511) cannot obtain the MIB even if it decodes the SSB received from the third TRP (503). The terminal (511) can determine whether the MIB is included in the SSB only by decoding the SSB. The terminal (511) may consume unnecessary power to decode the SSB received from the third TRP (503). In addition, in order to find the SSB on which the MIB is transmitted, the terminal (511) may select other SSBs and may have to decode the selected SSBs again. In order to find the appropriate SSB, the terminal (511) may consume unnecessary power.

[0088] As another example, the second TRP (502) and the third TRP (503), which are LPTs, can transmit an SSB containing a MIB to the terminal (511). When the second TRP (502) and the third TRP (503), which are LPTs, transmit an SSB containing a MIB to the terminal (511), the following problems may occur.

[0089] When the second TRP (502) and the third TRP (503), which are LPTs, each transmit a MIB included in an SSB, the terminal (511) can receive the SSB and obtain the MIB included in the SSB. The terminal (511) can select the SSB received from the third TRP (503) closest to the terminal (511) as the optimal SSB.

[0090] The terminal (511) can decode the SSB received from the third TRP (503) to obtain the MIB included in the SSB. The MIB may include information for receiving system information block 1 (SIB1). Since the second TRP (502) and the third TRP (503) are LPTs, control information must also be transmitted to a minimum, and therefore transmission of SIB1 and the like may not occur.

[0091] The MIB included in the SSB may need to be notified to the terminal (511) that it has a different configuration from the MIB transmitted by the general TRP. This is because the second TRP (502) and the third TRP (503), which are LPTs, do not transmit SIB1. In other words, the MIB included in the SSB transmitted by the second TRP (502) and the third TRP (503), must notify the terminal (511) that it does not contain information about SIB1. In this way, additional time / frequency resources may be required for the MIB to notify that the MIB included in the SSB transmitted by the second TRP (502) and the third TRP (503), which are LPTs, is different from the general MIB. In other words, there is a problem that a configuration method for a new MIB needs to be proposed. Accordingly, the asymmetric scenario may not be suitable for improving the uplink capacity.

[0092] Asymmetric scenarios can lead to excessive uplink received power and uplink out-of-synchronization problems if proper uplink power control and uplink transmission timing are not implemented.

[0093] In the case of excessive uplink reception power problem, the second TRP (502) and the third TRP (503) can only transmit SSB in the downlink. When the terminal (511) transmits a signal to the second TRP (502) using the transmission power transmitted to the first TRP (501), the distance between the terminal (511) and the second TRP (502) is shorter than the distance between the terminal (511) and the first TRP (501), so the second TRP (502) can receive a physical signal and / or a physical channel with excessive transmission power from the terminal (511). When the terminal (511) transmits a signal to the second TRP (502) using the transmission power transmitted to the first TRP (501), strong interference may be caused to the adjacent third TRP (503). Such strong interference may result in interference boosting, which may cause strong interference to adjacent cells around the second TRP (502), and as a result, the goal of improving uplink capacity may not be achieved. Uplink capacity may refer to the transmission capacity of the uplink and may be expressed in units of bits per second (bps).

[0094] Due to the uplink desynchronization problem, if the terminal (511) transmits a signal to the second TRP (502) at the same transmission time as the time at which the terminal (511) transmits a signal to the first TRP (501), the second TRP (502) may not be able to receive the signal transmitted by the terminal (511) due to the uplink desynchronization problem. More specifically, according to the standard of the 3GPP communication system, a signal transmitted between a transmitting node and a receiving node may copy the last part of the data to be transmitted and add a cyclic prefix (CP) to the peak of the data to be transmitted. If the terminal (511) transmits a signal to the second TRP (502) at the same transmission time as the time at which the terminal (511) transmits a signal to the first TRP (501), the second TRP (502) may receive the signal transmitted by the terminal (511) at a location outside of ±0.5TCP, which is a range that the second TRP (502) can receive. TCP may mean the transmission time duration of CP for one symbol of a physical signal (or physical channel) transmitted by a terminal (511).

[0095] If the second TRP (502) receives a signal transmitted by the terminal (511) outside the range of ±0.5TCP that the second TRP (502) can receive, the orthogonality of the received signal may not be guaranteed. Even if the second TRP (502) receives the signal transmitted by the terminal (511), it cannot demodulate it. This problem may ultimately result in failure to achieve the goal of improving the uplink capacity of the mobile communication system.

[0096] The signal received from the terminal (511) at the second TRP (502) has a very high signal-to-noise ratio (SNR), so if the uplink asynchrony problem can be resolved, uplink capacity can be improved. In other words, resolving the uplink asynchrony problem can be a very important issue. Below, the present disclosure can propose a signal transmission method and procedure from the initial system connection setup stage of the terminal to the transmission of uplink data to resolve the problems of excessive uplink reception power and uplink asynchrony in an asymmetric scenario.

[0097] Figure 6 is a flowchart illustrating embodiments of an initial system connection setup method.

[0098] Referring to FIG. 6, a communication system may include M NPTs (NPT 0 to NPT M-1), U terminals (UE 0 to UE U-1), and N LPTs (LPT K to LPT K+N-1). M, U, K, and N may be positive integers. A first NPT (NPT 0) may be a normal power TRP. The first NPT may control the N LPTs (LPT K to LPT K+N-1). The first NPT may use a power greater than the power used by the N LPTs (LPT K to LPT K+N-1).

[0099] A first NPT (NPT 0), U terminals (UE 0 to UE U-1), and N LPTs (LPT K to LPT K+N-1) can perform an initial system access setup process (S600). The first NPT can transmit beamformed first synchronization signal blocks (SSBs) in multiple directions (S611). The first terminal (UE 0) can receive the first SSBs beamformed in multiple directions from the first NPT. Alternatively, the first NPT can repeatedly transmit the first SSBs in a quasi-omni-directional manner. The first terminal can receive the first SSBs repeatedly transmitted in a quasi-omni-directional manner from the first NPT.

[0100] <SSB의 제1 실시예>

[0101] The first SSB transmitted from the first NPT may be configured as a first synchronization signal for enabling the first terminal to recognize the PCI ID (identifier) ​​of the first NPT, for example, as shown in Table 1, a second synchronization signal for enabling the first terminal to recognize the TRP ID of the first NPT, a third synchronization signal for enabling the first terminal to recognize the beam ID of the beam transmitted from the first NPT, and a physical broadcast channel (PBCH) including a master information block (MIB) of the first NPT.

[0102] - A first synchronization signal to recognize a PCI ID - A second synchronization signal to recognize a TRP ID - A third synchronization signal to recognize a beam ID - A PBCH including an MIB

[0103] A first synchronization signal for recognizing a PCI ID of a first NPT may include a PCI ID. A second synchronization signal for recognizing a TRP ID of the first NPT may include a TRP ID of the first NPT. A third synchronization signal for recognizing a beam ID of a beam transmitted from the first NPT may include a beam ID. The PCI ID may be represented by x. X may have a value from 0 to X-1. The x of the first NPT may be, for example, p. P may be any value from 0 to X-1. The TRP ID may be represented by y. Y may be 0 to Y-1. A y value from 0 to M-1 may be assigned to an NPT. A y value from K to K+N-1 may be assigned to an LPT. The y of the first NPT may be, for example, 0. The beam ID may be represented by z. z can have a value from 0 to Z-1. z of the first NPT can be, for example, 3. K, M, N, X, Y and Z can be real numbers. The terminal may know that y values ​​from 0 to M-1 are assigned to the NPT and y values ​​from K to K+N-1 are assigned to the LPT. The PCI ID can be mapped to a first synchronization signal configured in the SSB. In addition, the TRP ID can be mapped to a second synchronization signal configured in the SSB. The second synchronization signal can be mapped to the same frequency resource and time resource as the first synchronization signal defined for mapping the PCI ID. The second synchronization signal can be mapped to partially the same frequency resource and time resource as the first synchronization signal defined for mapping the PCI ID. The second synchronization signal can be mapped to partially different frequency resource and time resource than the first synchronization signal defined for mapping the PCI ID.

[0104] When the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can be element-wise multiplied. In other words, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can generate an element-wise multiplied synchronization signal. When the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can be element-wise exclusive-ORed. In other words, when the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can generate an element-wise exclusive-ORed synchronization signal. The PCI ID and the TRP ID can be mapped to a common synchronization signal. In other words, a common synchronization signal may include a PCI ID and a TRP ID.

[0105] When the first synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the third synchronization signal for the beam ID can be multiplied between elements. In other words, the first synchronization signal for the PCI ID and the third synchronization signal for the beam ID can generate a multiplied synchronization signal between elements. When the first synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the third synchronization signal for the beam ID can be exclusive-ORed between elements. In other words, when the first synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the third synchronization signal for the beam ID can generate a exclusive-ORed synchronization signal between elements. The PCI ID and the beam ID can be mapped to a common synchronization signal. In other words, the common synchronization signal can include the PCI ID and the beam ID.

[0106] When the second synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the second synchronization signal for the TRP ID and the third synchronization signal for the beam ID can be multiplied between elements. In other words, the second synchronization signal for the TRP ID and the third synchronization signal for the beam ID can generate a multiplied synchronization signal between elements. When the second synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the second synchronization signal for the TRP ID and the third synchronization signal for the beam ID can be exclusive-ORed between elements. In other words, when the second synchronization signal and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the second synchronization signal for the TRP ID and the third synchronization signal for the beam ID can generate a exclusive-ORed synchronization signal between elements. The TRP ID and the beam ID can be mapped to a common synchronization signal. In other words, the common synchronization signal can include the TRP ID and the beam ID.

[0107] When the first synchronization signal, the second synchronization signal, and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID, the second synchronization signal for the TRP ID, and the third synchronization signal for the beam ID can be element-to-element multiplied. In other words, the first synchronization signal for the PCI ID, the second synchronization signal for the TRP ID, and the third synchronization signal for the beam ID can generate an element-to-element multiplied synchronization signal. When the first synchronization signal, the second synchronization signal, and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID, the second synchronization signal for the TRP ID, and the third synchronization signal for the beam ID can be element-to-element exclusive-ORed. In other words, when the first synchronization signal, the second synchronization signal, and the third synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID, the second synchronization signal for the TRP ID, and the third synchronization signal for the beam ID can generate a synchronization signal that is exclusive-ORed between elements. The PCI ID, the TRP ID, and the beam ID can be mapped to a common synchronization signal. In other words, the common synchronization signal can include the PCI ID, the TRP ID, and the beam ID.

[0108] The first LPT can transmit the first SSBs beamformed in multiple directions (S621). The first terminal can receive the first SSBs beamformed in multiple directions from the first LPT. Alternatively, the first LPT can repeatedly transmit the first SSBs in a semi-omnidirectional manner. The first terminal can receive the first SSBs repeatedly transmitted in a semi-omnidirectional manner from the first LPT.

[0109] The first SSB transmitted from the first LPT may include, for example, a first synchronization signal for enabling the first terminal to recognize the PCI ID of the first LPT, a second synchronization signal for enabling the first terminal to recognize the TRP ID of the first LPT, and a third synchronization signal for enabling the first terminal to recognize the beam ID, as shown in Table 1. The first SSB transmitted from the first LPT may include a MIB, as shown in Table 1. Alternatively, the first SSB transmitted from the first LPT may not include a MIB.

[0110] The first synchronization signal for recognizing the PCI ID of the first LPT may include the PCI ID. The second synchronization signal for recognizing the TRP ID of the first LPT may include the TRP ID of the first LPT. The third synchronization signal for recognizing the beam ID of the first LPT may include the beam ID. The PCI ID x of the first LPT may be, for example, p. The TRP ID y of the first LPT may be K. The beam ID z of the first LPT may be, for example, 7.

[0111] In this process, the first terminal can receive the SSBs transmitted first from the first NPT and the first LPT. The best SSB in the first SSBs received by the first terminal can have p as the PCI ID, K as the TRP ID, and 7 as the beam ID. The best SSB can be the SSB received by the first terminal from the first LPT. The next best SSB in the first SSBs received by the first terminal can have p as the PCI ID, 0 as the TRP ID, and 3 as the beam ID. The next best SSB can be the SSB received by the first terminal from the first NPT. The best SSB and the next best SSB can have the same PCI ID. The first NPT may not be the TRP that transmitted the best SSB. The first NPT may be the TRP that transmitted the next best SSB.

[0112] The best SSB can be the SSB with the largest maximum correlation value. The next best SSB can have the second maximum correlation value. The best SSB can be the SSB with the largest signal to interference plus noise ratio (SINR). The next best SSB can have the second SINR. The best SSB is the first best SSB (i.e., 1 st The second best SSB (i.e. 2 best SSB) may be the second best SSB. nd It may be the best SSB.

[0113] The first terminal can perform synchronization of the downlink from the first NPT to the first terminal based on one of the first SSBs received from the first NPT. The one SSB may be a suboptimal SSB and may have a PCI ID of p, a TRP ID of 0, and a beam ID of 3. In this way, the first terminal can perform a synchronization process according to the first NPT.

[0114] The first terminal can perform synchronization of the downlink from the first LPT to the first terminal based on one of the first SSBs received from the first LPT. The one SSB may be a best-effort SSB and may have p as the PCI ID, K as the TRP ID, and 7 as the beam ID. In this way, the first terminal can perform the synchronization process according to the first LPT.

[0115] The present disclosure also includes a case where the first LPT has a different PCI ID than the first NPT. Even if the first NPT is not the TRP that transmitted the best-effort SSB, the first terminal can recognize that the TRP that transmitted the best-effort SSB is the first LPT under the control of the first NPT. Furthermore, the first terminal can recognize that the TRP that transmitted the second-effort SSB is the first NPT capable of transmitting and receiving all channels / signals in the DL and UL.

[0116] The first NPT can transmit the beamformed second synchronization signal blocks in multiple directions (S612). The first terminal can receive the second SSBs beamformed in multiple directions from the first NPT. Alternatively, the first NPT can repeatedly transmit the second SSBs in a quasi-omnidirectional manner. The first terminal can receive the second SSBs repeatedly transmitted in a quasi-omnidirectional manner from the first NPT. The first synchronization signal block and the second synchronization signal block transmitted from the first NPT can be transmitted at different times as the same synchronization signal block.

[0117] The second SSB transmitted from the first NPT may be configured as a PBCH including a first synchronization signal for enabling the first terminal to recognize the PCI ID of the first NPT, a second synchronization signal for enabling the first terminal to recognize the TRP ID of the first NPT, a third synchronization signal for enabling the first terminal to recognize the beam ID of the beam transmitted from the first NPT, and a master information block of the first NPT, as shown in Table 1.

[0118] The terminal can obtain a TRP ID from one of the second SSBs, which may be, for example, 0. The SSB may be a secondary SSB and may have p as the PCI ID, 0 as the TRP ID, and 3 as the beam ID. If the terminal obtains 0 as the TRP ID, the terminal can determine the TRP that transmitted the second SSB as the first NPT. The terminal can obtain a MIB from the second SSB. The MIB may be system information obtained by the first terminal from the first NPT. The MIB may be an RRC (radio resource control) message received from the first NPT.

[0119] The first LPT can transmit the beamformed second synchronization signal blocks in multiple directions (S622). The first terminal can receive the second SSBs beamformed in multiple directions from the first LPT. Alternatively, the first LPT can repeatedly transmit the second SSBs in a quasi-omnidirectional manner. The first terminal can receive the second SSBs repeatedly transmitted in a quasi-omnidirectional manner from the first LPT. The first synchronization signal block and the second synchronization signal block transmitted from the first LPT can be transmitted at different times as the same synchronization signal block.

[0120] The second SSB transmitted from the first LPT may be configured with a first synchronization signal for allowing the first terminal to recognize the PCI ID of the first LPT, a second synchronization signal for allowing the first terminal to recognize the TRP ID of the first LPT, a third synchronization signal for allowing the first terminal to recognize the beam ID of the beam transmitted from the first LPT, and a PBCH including a master information block of the first LPT, as shown in Table 1. In this way, the second SSB transmitted from the first LPT may include the PBCH, as shown in Table 1. Alternatively, the second SSB transmitted from the first LPT may not include the PBCH. In other words, the second SSB transmitted from the first LPT may include the MIB. Alternatively, the second SSB transmitted from the first LPT may not include the MIB.

[0121] The terminal can obtain a TRP ID from one of the second SSBs, for example, K. The one SSB can be a best SSB and can have p as a PCI ID, K as a TRP ID, and 7 as a beam ID. The terminal can obtain a MIB from one of the second SSBs. The MIB can be system information obtained from the first LPT by the first terminal. The MIB can be an RRC message received from the first LPT by the first terminal. Alternatively, the terminal can obtain K as a TRP ID and determine the TRP that transmitted the second SSB as the first LPT. Accordingly, the terminal may not attempt to obtain the MIB from the second SSB.

[0122] <SSB의 제2 실시예>

[0123] The first SSB transmitted from the first NPT may be configured with a first synchronization signal for allowing the first terminal to recognize the PCI ID of the first NPT, a second synchronization signal for allowing the first terminal to recognize the TRP ID of the first NPT, and a PBCH including an MIB, as shown in Table 2. The first synchronization signal for allowing the first terminal to recognize the PCI ID of the first NPT may include the PCI ID. The second synchronization signal for allowing the first NPT to recognize the TRP ID of the first NPT may include the TRP ID of the first NPT. The PBCH for allowing the first NPT to recognize the beam ID of the beam transmitted may include the beam ID of the beam transmitted from the first NPT.

[0124] - A first synchronization signal to recognize the PCI ID - A second synchronization signal to recognize the TRP ID - A PBCH to recognize the beam ID and including the MIB

[0125] The PCI ID may be represented by x. x may have a value from 0 to X-1. The x of the first NPT may be, for example, p. p may be any value from 0 to X-1. The TRP ID may be represented by y. y may be 0 to Y-1. y values ​​from 0 to M-1 may be assigned to the NPT. y values ​​from K to K+N-1 may be assigned to the LPT. y of the first NPT may be, for example, 0. The beam ID may be represented by z. z may have a value from 0 to Z-1. z of the first NPT may be, for example, 3. K, M, N, X, Y and Z may be real numbers. The terminal may know that y values ​​from 0 to M-1 are assigned to NPT, and y values ​​from K to K+N-1 are assigned to LPT. The PCI ID may be mapped to a first synchronization signal configured in the SSB. In addition, the TRP ID may be mapped to a second synchronization signal configured in the SSB. The second synchronization signal may be mapped to the same frequency resources and time resources as the first synchronization signal specified for mapping the PCI ID. The second synchronization signal may be mapped to partially the same frequency resources and time resources as the first synchronization signal specified for mapping the PCI ID. The second synchronization signal may be mapped to partially different frequency resources and time resources than the first synchronization signal specified for mapping the PCI ID. When the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resources and time resources, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID may be element-wise multiplied. In other words, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can generate a synchronization signal multiplied between elements.When the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can be exclusively ORed between elements. In other words, when the first synchronization signal and the second synchronization signal are mapped to the same or partially the same frequency resource and time resource, the first synchronization signal for the PCI ID and the second synchronization signal for the TRP ID can generate a synchronization signal that is exclusively ORed between elements. The PCI ID and the TRP ID can be mapped to a common synchronization signal. In other words, the common synchronization signal can include the PCI ID and the TRP ID.

[0126] The first SSBs transmitted from the first LPT may be configured with, for example, a first synchronization signal for allowing the first terminal to recognize the PCI ID of the first LPT, a second synchronization signal for allowing the first terminal to recognize the TRP ID of the first LPT, and a PBCH for allowing the first terminal to recognize the beam ID, and including an MIB, as shown in Table 2. The first synchronization signal for allowing the first terminal to recognize the PCI ID of the first LPT may include the PCI ID. The second synchronization signal for allowing the first LPT to recognize the TRP ID of the first LPT may include the TRP ID of the first LPT. The PBCH for allowing the first terminal to recognize the beam ID of the beam transmitted from the first LPT may include the beam ID. The PBCH may include the MIB associated with the first LPT. Alternatively, the PBCH may not include the MIB associated with the first LPT. The PCI ID x of the first LPT may be, for example, p. The TRP ID of the first LPT, y, can be, for example, 0. The beam ID of the first LPT, z, can be, for example, 7.

[0127] In this process, the first terminal can receive the SSBs transmitted first from the first NPT and the first LPT. The best SSB in the first SSBs received by the first terminal can have p as the PCI ID, K as the TRP ID, and 7 as the beam ID. The best SSB can be the SSB received by the first terminal from the first LPT. The next best SSB in the first SSBs received by the first terminal can have p as the PCI ID, 0 as the TRP ID, and 3 as the beam ID. The next best SSB can be the SSB received by the first terminal from the first NPT. The best SSB and the next best SSB can have the same PCI ID. The first NPT may not be the TRP that transmitted the best SSB. The first NPT may be the TRP that transmitted the next best SSB.

[0128] The best SSB can be the SSB with the largest maximum correlation value. The next best SSB can have the second maximum correlation value. The best SSB can be the SSB with the largest SINR. The next best SSB can have the second SINR. The best SSB is the first best SSB (i.e., 1 st The second best SSB (i.e. 2 best SSB) may be the second best SSB. nd It may be the best SSB.

[0129] The first terminal can perform synchronization of the downlink from the first NPT to the first terminal based on one of the first SSBs received from the first NPT. The one SSB may be a suboptimal SSB and may have a PCI ID of p, a TRP ID of 0, and a beam ID of 3. In this way, the first terminal can perform a synchronization process according to the first NPT.

[0130] The first terminal can perform synchronization of the downlink from the first LPT to the first terminal based on one of the first SSBs received from the first LPT. The one SSB may be a best-effort SSB and may have p as the PCI ID, K as the TRP ID, and 7 as the beam ID. In this way, the first terminal can perform the synchronization process according to the first LPT.

[0131] The present disclosure also includes a case where the first LPT has a different PCI ID than the first NPT. Even if the first NPT is not the TRP that transmitted the best-effort SSB, the first terminal can recognize that the TRP that transmitted the best-effort SSB is the first LPT under the control of the first NPT. Furthermore, the first terminal can recognize that the TRP that transmitted the second-effort SSB is the first NPT capable of transmitting and receiving all channels / signals in the DL and UL.

[0132] The second SSB transmitted from the first NPT may be configured as a first synchronization signal for enabling the first terminal to recognize the PCI ID of the first NPT, a second synchronization signal for enabling the first terminal to recognize the TRP ID of the first NPT, and a PBCH for enabling the first terminal to recognize the beam ID of the beam transmitted from the first NPT, and including a master information block of the first NPT, as shown in Table 2.

[0133] The terminal can obtain a TRP ID from one of the second SSBs, which may be, for example, 0. The SSB may be a secondary SSB and may have p as the PCI ID, 0 as the TRP ID, and 3 as the beam ID. If the terminal obtains 0 as the TRP ID, the terminal can determine the TRP that transmitted the second SSB as the first NPT. The terminal can obtain a MIB from the second SSB. The MIB may be system information obtained by the first terminal from the first NPT. The MIB may be an RRC message received from the first NPT.

[0134] The second SSB transmitted from the first LPT may be configured with a first synchronization signal for allowing the first terminal to recognize the PCI ID of the first LPT, a second synchronization signal for allowing the first terminal to recognize the TRP ID of the first LPT, and a PBCH for allowing the first terminal to recognize the beam ID of the beam transmitted from the first LPT, and including a master information block of the first LPT, as shown in Table 2. In this way, the second SSB transmitted from the first LPT may include the PBCH, as shown in Table 2. Alternatively, the second SSB transmitted from the first LPT may not include the PBCH. In other words, the second SSB transmitted from the first LPT may include the MIB. Alternatively, the second SSB transmitted from the first LPT may not include the MIB.

[0135] The terminal can obtain a TRP ID from one of the second SSBs, for example, K. The one SSB can be a best SSB and can have p as a PCI ID, K as a TRP ID, and 7 as a beam ID. The terminal can obtain a MIB from one of the second SSBs. The MIB can be system information obtained from the first LPT by the first terminal. The MIB can be an RRC message received from the first LPT by the first terminal. Alternatively, the terminal can obtain K as a TRP ID and determine the TRP that transmitted the second SSB as the first LPT. Accordingly, the terminal may not attempt to obtain the MIB from the second SSB.

[0136] <MIB의 실시예 1>

[0137] Table 3 may be examples of MIB sequences representing MIB system information.

[0138] MIB ::= SEQUENCE {systemFrameNumber(6bits)BIT STRING (SIZE (6)),subCarrierSpacingCommon(1bit) ENUMERATED {scs30or120, scs60or240},ssb-SubcarrierOffset(4bits) INTEGER (0..15),dmrs-TypeA-Position(1bit)ENUMERATED {pos2, pos3},pdcch-ConfigSIB1(8bits) INTEGER (0..255),cellBarred(1bit) ENUMERATED{barred, notBarred},intraFreqReselection(1bit) ENUMERATED {allowed, notAllowed}Spare(1 bit)}

[0139] Referring to Table 3, MIB system information can include systemFrameNumber, subCarrierSpacingCommon, ssb-SubcarrierOffset, dmrs-TypeA-Position, pdcch-ConfigSIB1, cellBarred, intraFreqReselection, and spare. systemFrameNumber can refer to part or all of the SFN (system frame number). subCarrierSpacingCommon can refer to the SCS (subcarrier spacing). ssb-SubcarrierOffset can refer to the location of the SSB among the available frequency resources. dmrs-TypeA-Position can refer to the location of the DMRS (demodulation reference signal) for MIB restoration. pdcch-ConfigSIB1 can refer to the location of the SIB1 following the MIB. cellBarred can refer to whether or not cell barring is enabled. intraFreqReselection may indicate whether intra-frequency reselection is allowed. The MIB system information in Table 3 is only an example and may be composed of information required for restoring SIB1 (e.g., pdcch-ConfigSIB1) and other information. Unlike Table 3, the MIB system information may be composed of information required for restoring SIB1 and some of the information other than the information required for restoring SIB1 in Table 3, as well as other information. Unlike Table 3, the MIB system information may not include information required for restoring SIB1 and all other information other than the information required for restoring SIB1 in Table 3, and may include completely new information. The MIB in Table 3 may be included in the SSB in Table 1.<MIB의 실시예 2>

[0140] Table 4 may be examples of MIB sequences representing MIB system information.

[0141] MIB ::= SEQUENCE {LPTindicator(1bit) ENUMEATED {TRP, LPT},systemFrameNumber(6bits)BIT STRING (SIZE (6)),subCarrierSpacingCommon(1bit) ENUMERATED {scs30or120, scs60or240},ssb-SubcarrierOffset(4bits) INTEGER (0..15),dmrs-TypeA-Position(1bit)ENUMERATED {pos2, pos3},pdcch-ConfigSIB1(8bits) INTEGER (0..255),cellBarred(1bit) ENUMERATED{barred, notBarred},intraFreqReselection(1bit) ENUMERATED {allowed, notAllowed}}

[0142] Referring to Table 4, the system information of the MIB can include LPTindicator, systemFrameNumber, subCarrierSpacingCommon, ssb-SubcarrierOffset, dmrs-TypeA-Position, pdcch-ConfigSIB1, cellBarred, and intraFreqReselection. LPTindicator can indicate whether the TRP that transmitted the MIB is NPT or LPT. systemFrameNumber can indicate part or all of the SFN. subCarrierSpacingCommon can indicate the SCS. ssb-SubcarrierOffset can indicate the location of the SSB among the available frequency resources. dmrs-TypeA-Position can indicate the location of the DMRS for MIB restoration. pdcch-ConfigSIB1 can indicate the location of the SIB1 following the MIB. cellBarred can indicate whether cell barring is performed. intraFreqReselection may indicate whether intra frequency reselection is allowed. The MIB system information in Table 4 is only an example and may consist of information required for restoring SIB1 (e.g., pdcch-ConfigSIB1) and other information. Unlike Table 4, the MIB system information may consist of information required for restoring SIB1 and some of the information other than the information required for restoring SIB1 in Table 4, as well as other information. Unlike Table 4, the MIB system information may not include information required for restoring SIB1 and all other information other than the information required for restoring SIB1 in Table 4, and may include completely new information. The MIB system information in Table 4 may be included in the SSB in Table 2.<MIB의 실시예 3>

[0143] Table 5 may be examples of MIB sequences of MIB system information.

[0144] MIB ::= SEQUENCE {LPTindicator(1bit) ENUMEATED {TRP, LPT},systemFrameNumber(6 bits) BIT STRING (SIZE (6)),subCarrierSpacingCommon(1bit) ENUMERATED {scs30or120, scs60or240},ssb-SubcarrierOffset(4bits)INTEGER (0..15),TxRelatedPower(4 bits) InTEGER ()Ro-Position(7 bits) INTEGER (0..127)}

[0145] Referring to Table 5, the system information of the MIB may include LPTindicator, systemFrameNumber, subCarrierSpacingCommon, ssb-SubcarrierOffset, TxRelatedPower, and Ro-Position. LPTindicator may indicate whether the TRP that transmitted the MIB is NPT or LPT. systemFrameNumber may indicate part or all of the SFN. subCarrierSpacingCommon may indicate SCS. TxRelatedPower may indicate transmission-related power information to enable deriving the transmission power required to transmit a signal to the TRP. Ro-Position may indicate an RO (random access channel occasion) corresponding to position information of time and frequency resources that can transmit a preamble. The signal may be a preamble or an SRS (sounding reference signal). When the MIB is received from the first NPT, the transmission-related information may include transmission-related power information for deriving the transmission power required to transmit a signal from the first terminal to the first NPT. When the MIB is received from the first NPT, the transmission-related information may further include transmission-related power information for deriving the transmission power required to transmit a signal from the first terminal to the first LPT. When the MIB is received from the first LPT, the transmission-related information may refer to transmission-related power information for deriving the transmission power required to transmit a signal from the first terminal to the first LPT. When the MIB is received from the first NPT, the Ro-Position may include information on RO corresponding to position information of time resources and frequency resources at which the first terminal can transmit a preamble to the first NPT.When the MIB is received from the first NPT, the Ro-Position may further include information about the RO corresponding to the position information of the time resource and frequency resource that can transmit the preamble from the first terminal to the first LPT. When the MIB is received from the first LPT, the Ro-Position may include information about the RO corresponding to the position information of the time resource and frequency resource that can transmit the preamble from the first terminal to the first LPT.

[0146] The MIB system information in Table 5 is only an example and may be composed of information required for restoring SIB1 (e.g., pdcch-ConfigSIB1) and other information. Unlike Table 5, the MIB system information may be composed of information required for restoring SIB1 and some of the information other than the information required for restoring SIB1 in Table 5, as well as other information. Unlike Table 5, the MIB system information may not include information required for restoring SIB1 and all other information other than the information required for restoring SIB1 in Table 5, and may include completely new information.

[0147] The system information of the MIB in Table 5 can be included in the SSB in Table 2. The RO information can be divided into multiple detailed information bits, such as the location of the time resource or frequency resource(s) to which one SSB is allocated, the location of the time resource or frequency resource(s) to which one SSB group is allocated, etc.

[0148] Figures 7a to 7d are conceptual diagrams illustrating embodiments of random access channel occasions.

[0149] Referring to Fig. 7a, in the SSB-RO mapping relationship according to the RACH (random access channel) setting, 64 temporally distinct SSBs (SSB 0 to SSB 63) on the first frequency band can be mapped one-to-one with 64 temporally distinct ROs (RO #0 to RO #63). For example, SSB 0 can be mapped to RO #0, and SSB 1 can be mapped to RO #1. In SSB 0, O can be a beam ID.

[0150] Referring to FIG. 7b, in the SSB-RO mapping relationship according to the RACH configuration, 64 temporally distinct SSBs (SSB 0 to SSB 63) on the first frequency band may be mapped one-to-one with 64 temporally distinct ROs (RO #0 to RO #252). For example, SSB 0 may be mapped to RO #0, and SSB 1 may be mapped to RO #4. ​​On the second frequency band, 64 temporally distinct SSBs (SSB 0 to SSB 63) may be mapped one-to-one with 64 temporally distinct ROs (RO #1 to RO #253). For example, SSB 0 may be mapped to RO #1, and SSB 1 may be mapped to RO #5. In the third frequency band, 64 temporally distinct SSBs (SSB 0 to SSB 63) can be mapped one-to-one with 64 temporally distinct ROs (RO #2 to RO #254). For example, SSB 0 can be mapped to RO #2, SSB 1 can be mapped to RO #6, and so on. In the fourth frequency band, 64 temporally distinct SSBs (SSB 0 to SSB 63) can be mapped one-to-one with 64 temporally distinct ROs (RO #3 to RO #255). For example, SSB 0 can be mapped to RO #3, SSB 1 can be mapped to RO #7, and so on.

[0151] Referring to FIG. 7c, in the SSB-RO mapping relationship according to the RACH configuration, a plurality of SSB sets (SSB 0~1, SSB 4~5, to SSB 60~61) that are distinct from each other in time in the first frequency band can be mapped one-to-one with a plurality of ROs (RO #0, RO #2, to RO #62) that are distinct from each other in time. For example, SSB 0~1 can be mapped to RO #0, and SSB 4~5 can be mapped to RO #2. In the second frequency band, a plurality of SSB sets (SSB 2~3, SSB 6~7, to SSB 62~63) that are distinct from each other in time can be mapped one-to-one with a plurality of ROs (RO #1, RO #3, to RO #63) that are distinct from each other in time. For example, SSB 2~3 may be mapped to RO #1, SSB 6~7 may be mapped to RO #3, and so on.

[0152] Referring to FIG. 7d, in the SSB-RO mapping relationship according to the RACH configuration, a plurality of SSB sets (SSB 0~1, SSB 4~5, to SSB 60~61) that are distinct from each other in time in the first frequency band can be mapped one-to-one with a plurality of ROs (RO #0, RO #2, to RO #62) that are distinct from each other in time. For example, SSB 0~1 can be mapped to RO #0, and SSB 4~5 can be mapped to RO #2. In the second frequency band, a plurality of SSB sets (SSB 2~3, SSB 6~7, to SSB 62~63) that are distinct from each other in time can be mapped one-to-one with a plurality of ROs (RO #1, RO #3, to RO #63) that are distinct from each other in time. For example, SSB 2~3 may be mapped to RO #1, SSB 6~7 may be mapped to RO #3, and so on.

[0153] In the third frequency band, a plurality of temporally distinct SSB sets (SSB 0~1, SSB 4~5, and so on, SSB 60~61) can be mapped one-to-one with a plurality of temporally distinct ROs (RO #0, RO #2, and so on, RO #62). For example, SSB 0~1 can be mapped to RO #0, SSB 4~5 can be mapped to RO #2, and so on. In the fourth frequency band, a plurality of temporally distinct SSB sets (SSB 2~3, SSB 6~7, and so on, SSB 62~63) can be mapped one-to-one with a plurality of temporally distinct ROs (RO #1, RO #3, and so on, RO #63). For example, SSB 2~3 can be mapped to RO #1, and SSB 6~7 can be mapped to RO #3.

[0154] Referring again to FIG. 6, the first NPT can transmit SIB1 to the first terminal using the time and frequency resources indicated in the MIB (S613). The first terminal can acquire SIB1 located in the time and frequency resources indicated in the MIB. At this time, the first NPT can transmit SIB1 to the first terminal by carrying it on a physical data shared channel (PDSCH). SIB1 may be system information acquired by the terminal. SIB1 may be an RRC message. The first terminal can be synchronized to the downlink of the first NPT.

[0155] The first NPT can transmit multiple SIBs, excluding SIB1, to the first terminal during the initial system access setup phase using the PDSCH. To this end, the first NPT can transmit scheduling and control information for SIB2 in SIB1. The first NPT can transmit SIB2 to the first terminal according to the scheduling and control information for SIB2. The first NPT can transmit scheduling and control information for SIB3 in SIB2. The first NPT can transmit SIB3 to the first terminal according to the scheduling and control information for SIB3. The first NPT can repeat this process until the scheduling and control information for all SIBs is transmitted, and can notify the first terminal that the SIBs will be transmitted sequentially following SIB1. The first NPT can transmit all SIBs to the first terminal according to the scheduling and control information for the SIBs.

[0156] A first terminal can receive scheduling and control information for SIB2 from SIB1. The first terminal can receive SIB2 from a first NPT based on the scheduling and control information for SIB2. The first terminal can receive scheduling and control information for SIB3 from SIB2. The first terminal can receive SIB3 from the first NPT based on the scheduling and control information for SIB3. It can be seen that the first terminal can repeat this process until it receives scheduling and control information for all SIBs, and can receive SIBs sequentially following SIB1. The first terminal can receive all SIBs from the first NPT based on the scheduling and control information for the SIBs.

[0157] The first NPT may not transmit multiple SIBs except SIB1 to the first terminal during the initial system connection setup phase to expedite the initial system connection setup procedure. The first NPT may transmit SIB1 to the first terminal, including control information indicating that multiple SIBs except SIB1 will not be transmitted to the first terminal. The first terminal may receive the control information indicating that multiple SIBs except SIB1 will not be transmitted to the first terminal from the first NPT. The first terminal may determine from the received control information that it cannot receive multiple SIBs except SIB1 from the first NPT. The first terminal cannot receive multiple SIBs except SIB1 from the first NPT.

[0158] To receive multiple SIBs other than SIB1, the first terminal may request all or part of the SIBs from the first NPT after completing the RRC reconfiguration. The first NPT may receive a request for all or part of the SIBs from the first terminal. The first NPT may transmit all or part of the SIBs requested by the first terminal to the first terminal. The first terminal may receive all or part of the SIBs from the first NPT.

[0159] Alternatively, the first terminal may request all or part of the SIB from the first NPT before completing the RRC reconfiguration. The first NPT may receive a request for all or part of the SIB from the first terminal. The first NPT may transmit all or part of the SIB according to the first request to the first terminal. The first terminal may receive all or part of the SIB from the first NPT. The first terminal may complete the reconfiguration according to the received RRC reconfiguration indication information and enter a system connection state. For convenience of explanation, it may be assumed below that the first terminal can only obtain SIB1 during the initial system access setup phase. However, the present disclosure may not be limited thereto.

[0160] SIB1 may include information about the transmission power of the first NPT, RO information, and other necessary information. The first terminal may obtain information about the transmission power of the first NPT, RO information, and other necessary information from SIB1 as indicated by the MIB to perform the initial system access setup process. Other necessary information may be a sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink. The sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink may be expressed as nTAoffset.

[0161] SIB1 may include information about the transmission power of the first LPT, RO information, and other necessary information. The first terminal may obtain information about the transmission power of the first LPT, RO information, and other necessary information from SIB1 as indicated by the MIB to perform the initial system access setup process. Other necessary information may be a sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink. The sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink may be expressed as nTAoffset.

[0162] In contrast, a MIB such as Table 5 may include information on the transmission power of the first NPT, RO information, and other necessary information. Other necessary information may be a sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink. The sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink may be represented by nTAoffset. In addition, the MIB of Table 5 may include information on the transmission power of the first LPT, RO information, and other necessary information. The first terminal may obtain information on the transmission power of the first LPT, RO information, and other necessary information from SIB1 indicated by the MIB in order to perform an initial system access setup process. Other necessary information may be a sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink. The sample value that is pulled forward (early) from the reception synchronization point acquired from the downlink may be represented by nTAoffset.

[0163] In this way, the first terminal can perform synchronization for the downlink of the first NPT and obtain system information related to the first NPT. The first terminal can perform synchronization for the downlink of the first LPT and obtain system information related to the first LPT. The first NPT, the LPTs, and the first terminal can perform an initial random access setup procedure (S630).

[0164] Figure 8 is a flowchart illustrating embodiments of an initial random access setup method.

[0165] Referring to FIG. 8, the first terminal may perform an initial random access setup procedure based on a 4-step CBRA (contention-based random access) for uplink synchronization (S800). The first NPT may transmit preambles that can be used to transmit a preamble from the first terminal to the first NPT to the first terminal via SIB1. The first terminal may obtain preambles that can be used to transmit a preamble to the first NPT from the SIB.

[0166] The first terminal can randomly select one preamble from among the preambles that can be used to transmit a preamble to the first NPT received from the first NPT in step 1. The first terminal can transmit the selected preamble to the first NPT via a physical random access channel (PRACH) (S811). The PRACH can be message 1 (Msg1). The first NPT can receive the preamble from the first terminal via the PRACH. The beam direction can be based on the reciprocal uplink direction of the beam direction when a signal is received in the downlink. The resource for transmitting the preamble from the first terminal to the first NPT can be based on information about the correlation between the SSB and the RACH (i.e., RO) acquired in advance from SIB1. The first NPT can estimate the propagation delay time of the first terminal using the preamble. The first terminal can set a random access response (RAR) window for receiving a RAR from the first NPT after transmitting Msg1. The first terminal may not receive an RAR from the first NPT during the RAR window time. The first terminal can determine that the transmission of Msg1 to the first NPT has failed and can increase the transmission power to retransmit the preamble to the first NPT.

[0167] The first NPT can communicate to the first terminal via SIB1 about preambles that can be used to transmit a preamble from the first terminal to the first LPT. The first terminal can acquire preambles that can be used to transmit a preamble from the SIB to the first LPT. Alternatively, the first terminal can acquire preambles that can be used to transmit a preamble to the first LPT from the acquisition information of the SSB of the first LPT. In the first step, the first terminal can randomly select one preamble from among the preambles that can be used to transmit a preamble to the first LPT. The preamble that the first terminal selects to transmit to the first LPT may be the same as the preamble that the first terminal selects to transmit to the first NPT. Alternatively, the preamble that the first terminal selects to transmit to the first LPT may be different from the preamble that the first terminal selects to transmit to the first NPT. The first terminal can transmit the selected preamble to the first LPT via PRACH (S821). The PRACH may be Message 1 (Msg1). The first LPT can receive Message 1 including the preamble from the first terminal via PRACH. The beam direction may correspond to the complementary uplink direction of the beam direction when receiving a signal in the downlink. The resource for transmitting the preamble from the first terminal to the first LPT may be based on information about the correlation between the SSB and the RACH obtained in advance from SIB1 (i.e., RO). The first LPT can estimate the propagation delay time of the first terminal using the received preamble.

[0168] The first terminal can set a RAR window for receiving an RAR from the first LPT via the first NPT after transmitting Msg1. The first terminal may not receive an RAR from the first LPT via the first NPT during the RAR window period. The first terminal can determine that the transmission of Msg1 to the first LPT has failed and can increase the transmission power to retransmit the preamble to the first LPT.

[0169] Next, in step 2, the first NPT can determine whether a preamble exists in the signal received via the PRACH. The preamble can be randomly selected and transmitted by the first terminal. The first NPT cannot determine which terminal transmitted the preamble based on whether or not the preamble was detected. The first NPT cannot determine how many terminals used the detected preamble. The first NPT can generate the first RAR based on the index of the detected preamble.

[0170] The first RAR may include a random access preamble ID (RAPID), a timing advance / adjustment / alignment command (TAC), an uplink grant (UL grant), and a temporary cell radio network temporary identifier (TC-RNTI) generated by the first NPT. The TAC may be a value for correcting a time error estimated by receiving Msg2 from the first terminal for uplink synchronization for the first NPT. The uplink grant may be information that notifies the allocated uplink resources when transmitting Msg3 mentioned in step 3 from the terminal to the first NPT. The TC-RNTI is an RNTI temporarily issued to the first terminal and may be used for transmission and reception of Msg3 and Msg4 mentioned in step 4 with the first NPT.

[0171] In step 2, the first LPT can determine whether a preamble exists in a signal received via PRACH. The preamble can be randomly selected and transmitted by the first terminal. The first LPT cannot determine which terminal transmitted the preamble based on whether the preamble was detected. The first LPT cannot determine how many terminals used the detected preamble. The first LPT can generate a second RAR based on the index of the detected preamble. The first LPT can transmit the generated second RAR to the first NPT. The first NPT can receive the second RAR from the first LPT. The second RAR can include a RAPID, a TAC, an uplink grant, and a TC-RNTI generated by the first LPT. The TAC can be a value for correcting a time error estimated when the first terminal receives Msg2 for uplink synchronization for the first LPT. The uplink grant may be information indicating the allocated uplink resources when transmitting Msg3, mentioned in step 3, from the first terminal to the first LPT. The TC-RNTI is an RNTI temporarily issued to the first terminal and can be used for transmitting and receiving Msg3 and Msg4, mentioned in step 4.

[0172] The first NPT can generate Msg2 including the first RAR and the second RAR. The first NPT can transmit Msg2 including the first RAR and the second RAR to the first terminal through a PDSCH scrambled with a RA-RNTI (random access radio network temporary identifier) ​​(S812). The first terminal can receive the PDSCH including Msg2 from the first NPT. The first terminal and the first NTP can derive the RA-RNTI through the locations of the time resources and frequency resources of the RO where the preamble is transmitted. The scheduling information of the PDCCH can be mapped to the CSS (common search space) information (e.g., corresponding to pdcch-ConfigSIB1) in SIB1 acquired in advance by the first terminal. The locations of the PDCCH time resources and frequency resources are not fixed, but can be located at one location within the search space of the CSS. To determine these locations, the first terminal can perform blind PDCCH decoding for locations within the CSS. Consequently, the power consumption of the first terminal can be extreme.

[0173] In step 3, the first terminal can generate Msg3 including a scheduling request message (or connection request message) for the first NPT and a unique identifier of the first terminal. The connection request message may be an RRC setup request (RSR) message. The first terminal can transmit the scheduling request message (or connection request message) and Msg3 including the unique identifier of the first terminal to the first NPT through a physical uplink shared channel (PUSCH) by applying a temporary C-RNTI using the uplink radio resources indicated by the uplink grant information included in the first RAR (S813). The first NPT can receive the connection request message and Msg3 including the unique identifier of the first terminal from the first terminal. In step 1, more than one terminal may transmit the same preamble to the first NPT. Therefore, a preamble collision may occur. In such cases, all terminals that transmitted the same preamble may transmit messages using the same radio resources by referencing the same RAR. This may result in collisions.

[0174] In other words, terminals that transmitted the same preamble to the first NPT in Step 1 may ultimately experience resource conflicts when transmitting Step 3 messages. Accordingly, each terminal, including the first terminal, may initiate a contention resolution timer when transmitting Step 3 messages as part of a procedure to determine whether the transmitted Step 3 messages are in conflict and whether they are successfully decoded.

[0175] In step 3, the first terminal can generate a scheduling request message (or connection request message) for the first LPT and Msg3 including the first terminal's unique identification ID. The first terminal can transmit the scheduling request message (or connection request message) for the first LPT and Msg3 including the first terminal's unique identification ID to the first LPT by applying a temporary C-RNTI using the uplink radio resources indicated by the uplink grant information included in the second RAR (S822). The first LPT can receive the connection request message and Msg3 including the terminal's unique identification ID from the first terminal. In step 1, more than one terminal may transmit the same preamble to the first LPT. As a result, a preamble collision may occur. In this case, all terminals that transmitted the same preamble may transmit messages using the same radio resources by referring to the same RAR. This may cause a collision.

[0176] In other words, terminals that transmitted the same preamble to the first LPT in Phase 1 may ultimately experience resource conflicts when transmitting Phase 3 messages. Accordingly, each terminal, including the first terminal, may initiate a contention resolution timer when transmitting Phase 3 messages as part of a procedure to determine whether the transmitted Phase 3 messages collide and whether decoding was successful.

[0177] In step 4, the first NPT can decrypt the received step 3 message. The first NPT can generate a first contention resolution identity (CRI) message for the successfully decrypted message. The first LPT can decrypt the received step 3 message. The first LPT can generate a second CRI message for the successfully decrypted message. The first LPT can transmit the second CRI message to the first NPT. The first NPT can receive the second CRI message from the first LPT. The first NPT can generate Msg4 including the first CRI message and the second CRI message. The first NPT can transmit Msg4 including the first CRI message and the second CRI message to the first terminal via a CRI medium access control (MAC) control element (CE) of a PDSCH (S814). The first terminal can receive Msg4 including the first CRI message and the second CRI message from the first NPT. The first terminal can receive Msg4 before the contention resolution timer activated in step 3 expires.

[0178] In this case, the first terminal may consider the initial random access setup to be successful and may consider the temporary C-RNTI as its own C-RNTI for continued use in the system connection state. Alternatively, the first terminal may not receive Msg4, which includes the first CRI message and the second CRI message, before the contention resolution timer expires. In this case, the first terminal may determine that the decoding failed due to a collision of the messages transmitted in step 3, etc. Accordingly, the first terminal may perform a backoff. Thereafter, the first terminal may retry the initial random access setup procedure. The first NPT may define a maximum number of random access attempts to prevent random access channel congestion. The first NPT may inform the first terminal of information about the maximum number of random access attempts. The first terminal may receive information about the maximum number of random access attempts from the first NPT. The first terminal may attempt random access within the maximum number of attempts. The first terminal may fail to successfully connect within the maximum number of attempts. In this case, the first terminal may abandon the random connection attempt and retry the downlink synchronization.

[0179] Figure 9 is a flowchart illustrating embodiments of an initial random access setup method.

[0180] Referring to FIG. 9, a first terminal may perform a 4-step CBRA-based initial random access setup procedure for uplink synchronization (S900). The first NPT may transmit preambles that can be used to transmit a preamble from the first terminal to the first NPT to the first terminal via SIB1. The first terminal may obtain preambles that can be used to transmit a preamble to the first NPT from the SIB. The first terminal may randomly select one preamble from among the preambles that can be used to transmit a preamble to the first NPT received from the first NPT in step 1. The first terminal may transmit the selected preamble to the first NPT via a PRACH (S911). The PRACH may be message 1 (Msg1).

[0181] The first NPT can receive a preamble from the first terminal via the PRACH. The beam direction may be based on the complementary uplink direction of the beam direction when receiving a signal in the downlink. The resource for transmitting the preamble from the first terminal to the first NPT may be based on information about the correlation between the SSB and the RACH (i.e., RO) obtained in advance from SIB1. The first NPT can estimate the propagation delay time of the first terminal using the preamble. The first terminal can set a RAR window for receiving an RAR from the first NPT after transmitting Msg1. The first terminal may not receive an RAR from the first NPT during the RAR window time. The first terminal may determine that the transmission of Msg1 to the first NPT has failed and may increase the transmission power to retransmit the preamble to the first NPT.

[0182] The first NPT can transmit preambles that can be used to transmit a preamble from the first terminal to the first LPT via SIB1 to the first terminal. The first terminal can acquire preambles that can be used to transmit a preamble from the SIB to the first LPT. Alternatively, the first terminal can acquire preambles that can be used to transmit a preamble to the first LPT from the acquisition information of the SSB of the first LPT. In the first step, the first terminal can randomly select one preamble from among the preambles that can be used to transmit a preamble to the first LPT. The preamble selected by the first terminal to transmit to the first LPT may be the same as the preamble selected to transmit to the first NPT. Alternatively, the preamble selected by the first terminal to transmit to the first LPT may be different from the preamble selected to transmit to the first NPT.

[0183] The first terminal can transmit the selected preamble to the first LPT via PRACH (S921-1). The PRACH may be Message 1 (Msg1). The first LPT can receive Message 1 including the preamble from the first terminal via PRACH. The beam direction may correspond to the complementary uplink direction of the beam direction when receiving a signal in the downlink. The resource for transmitting the preamble from the first terminal to the first LPT may be based on information about the correlation between the SSB and the RACH obtained in advance from SIB1 (i.e., RO). The first LPT can estimate the propagation delay time of the first terminal using the received preamble.

[0184] The first terminal can set a RAR window to receive RAR from the first LPT via the first NPT after transmitting Msg1. The first terminal may not receive RAR from the first LPT via the first NPT during the RAR window period. The first terminal can determine that the transmission of Msg1 to the first LPT has failed and can increase the transmission power to retransmit the preamble to the first LPT.

[0185] Next, in step 2, the first NPT can determine whether a preamble exists in the signal received via the PRACH. The preamble can be randomly selected and transmitted by the first terminal. The first NPT cannot determine which terminal transmitted the preamble based on whether or not the preamble was detected. The first NPT cannot determine how many terminals used the detected preamble. The first NPT can generate the first RAR based on the index of the detected preamble.

[0186] The first RAR may include RAPID, TAC, uplink grant, TC-RNTI, etc. generated in the first NPT. Here, the TAC may be a value for correcting the time error estimated by receiving Msg2 from the first terminal for uplink synchronization for the first NPT. The uplink grant may be information that notifies the allocated uplink resources when transmitting Msg3 mentioned in step 3 from the terminal to the first NPT. The TC-RNTI is an RNTI temporarily issued to the first terminal and may be used for transmission and reception of Msg3 and Msg4 mentioned in step 4 with the first NPT.

[0187] In step 2, the first LPT can determine whether a preamble exists in a signal received via PRACH. The preamble can be randomly selected and transmitted by the first terminal. The first LPT cannot determine which terminal transmitted the preamble based on whether the preamble is detected. The first LPT cannot determine how many terminals used the detected preamble. The first LPT can determine whether a preamble exists in a signal received via PRACH. The first LPT cannot confirm the presence of a preamble in a signal received via PRACH. The first LPT can report a failure to confirm the presence of a preamble to the first NPT. The first NPT can receive a report from the first LPT about a failure to confirm the presence of a preamble.

[0188] A first NPT may generate a first RAR including a command instructing to retransmit a preamble for the first LPT and a maximum number of repetitions. The first NPT may transmit the first RAR including the command instructing to retransmit the preamble for the first LPT to a first terminal (S912-1). The first terminal may receive the first RAR including the command instructing to retransmit the preamble for the first LPT from the first NPT. The first terminal may retransmit the preamble to the first LPT within the maximum number of repetitions according to the command included in the received first RAR (S921-2). The first terminal may retransmit the preamble to the first LPT within the maximum number of repetitions by ramping the power to a higher transmit power than the transmit power at which the preamble was previously transmitted to the first LPT (power up-ramping).

[0189] The first LPT can receive Msg1 from the first terminal. The first LPT can determine whether a preamble exists in a signal received via PRACH. The preamble can be arbitrarily selected and transmitted by the first terminal. The first LPT cannot determine which terminal transmitted the preamble based on whether the preamble was detected. The first LPT cannot determine how many terminals used the detected preamble. The first LPT can generate a second RAR based on the index of the detected preamble. The first LPT can transmit the generated second RAR to the first NPT. The first NPT can receive the second RAR from the first LPT. The second RAR can include a RAPID, a TAC, an uplink grant, and a TC-RNTI generated by the first LPT. TAC may be a value for compensating for the estimated time error when the first terminal receives Msg2 for uplink synchronization for the first LPT. The uplink grant may be information indicating the allocated uplink resources when transmitting Msg3, mentioned in step 3, from the first terminal to the first LPT. The TC-RNTI is an RNTI temporarily issued to the first terminal and may be used for transmitting and receiving Msg3 and Msg4, mentioned in step 4.

[0190] The first NPT can generate Msg2 including the second RAR. The first NPT can transmit Msg2 including the second RAR to the first terminal via a PDSCH scrambled with RA-RNTI (S912-2). The first terminal can receive the PDSCH including Msg2 from the first NPT. The first terminal and the first NTP can derive the RA-RNTI based on the locations of the time resources and frequency resources of the RO where the preamble is transmitted. The scheduling information of the PDCCH can be mapped to the CSS information (e.g., corresponding to pdcch-ConfigSIB1) in SIB1 acquired in advance by the first terminal. The locations of the PDCCH time resources and frequency resources are not fixed, but can be located at a single location within the CSS search space. The first terminal can blindly perform PDCCH decoding for locations within the CSS to know this location. Accordingly, the power consumption of the first terminal can be extremely high.

[0191] In step 3, the first terminal can generate Msg3 including a scheduling request message (or connection request message) for the first NPT and a unique identifier of the first terminal. The connection request message may be an RRC setup request (RSR) message. The first terminal can transmit the scheduling request message (or connection request message) and Msg3 including the unique identifier of the first terminal to the first NPT through a physical uplink shared channel (PUSCH) by applying a temporary C-RNTI using the uplink radio resources indicated by the uplink grant information included in the first RAR (S913). The first NPT can receive the connection request message and Msg3 including the unique identifier of the first terminal from the first terminal. In step 1, more than one terminal may transmit the same preamble to the first NPT. Therefore, a preamble collision may occur. In such cases, all terminals that transmitted the same preamble may transmit messages using the same radio resources by referencing the same RAR. This may result in collisions.

[0192] In other words, terminals that transmitted the same preamble to the first NPT in Step 1 may ultimately experience resource conflicts when transmitting Step 3 messages. Accordingly, each terminal, including the first terminal, may initiate a contention resolution timer when transmitting Step 3 messages as part of a procedure to determine whether the transmitted Step 3 messages are in conflict and whether they are successfully decoded.

[0193] In step 3, the first terminal can generate a scheduling request message (or connection request message) for the first LPT and Msg3 including the first terminal's unique identification ID. The first terminal can transmit the scheduling request message (or connection request message) for the first LPT and Msg3 including the first terminal's unique identification ID to the first LPT by applying a temporary C-RNTI using the uplink radio resources indicated by the uplink grant information included in the second RAR (S922). The first LPT can receive the connection request message and Msg3 including the terminal's unique identification ID from the first terminal. In step 1, more than one terminal may transmit the same preamble to the first LPT. As a result, a preamble collision may occur. In this case, all terminals that transmitted the same preamble may transmit messages using the same radio resources by referring to the same RAR. This may cause a collision.

[0194] In other words, terminals that transmitted the same preamble to the first LPT in Phase 1 may ultimately experience resource conflicts when transmitting Phase 3 messages. Accordingly, each terminal, including the first terminal, may initiate a contention resolution timer when transmitting Phase 3 messages as part of a procedure to determine whether the transmitted Phase 3 messages collide and whether decoding was successful.

[0195] In step 4, the first NPT can decrypt the received step 3 message. The first NPT can generate a first CRI message for the successfully decrypted message. The first LPT can decrypt the received step 3 message. The first LPT can generate a second CRI message for the successfully decrypted message. The first LPT can transmit the second CRI message to the first NPT. The first NPT can receive the second CRI message from the first LPT. The first NPT can generate Msg4 including the first CRI message and the second CRI message. The first NPT can transmit Msg4 including the first CRI message and the second CRI message to the first terminal via the CRI MAC CE of the PDSCH (S914). The first terminal can receive Msg4 including the first CRI message and the second CRI message from the first NPT. The first terminal can receive Msg4 before the contention resolution timer activated in step 3 expires.

[0196] In this case, the first terminal may consider the initial random access setup to be successful and may consider the temporary C-RNTI as its own C-RNTI for continued use in the system connection state. Alternatively, the first terminal may not receive Msg4, which includes the first CRI message and the second CRI message, before the contention resolution timer expires. In this case, the first terminal may determine that the decoding failed due to a collision of the messages transmitted in step 3, etc. Accordingly, the first terminal may perform a backoff. Thereafter, the first terminal may retry the initial random access setup procedure. The first NPT may define a maximum number of random access attempts to prevent random access channel congestion. The first NPT may inform the first terminal of information about the maximum number of random access attempts. The first terminal may receive information about the maximum number of random access attempts from the first NPT. The first terminal may attempt random access within the maximum number of attempts. The first terminal may fail to successfully connect within the maximum number of attempts. In this case, the first terminal may abandon the random connection attempt and retry the downlink synchronization.

[0197] Referring again to FIG. 6, the first terminal, which has successfully completed the random access procedure, can generate a hybrid automatic repeat and request (HARQ) ACK / NACK message as a response to whether the message was successfully received from the first NPT. The first terminal can transmit the generated HARQ ACK / NACK message to the first NPT via the physical uplink control channel (PUCCH) (S640). The first NPT can receive the HARQ ACK / NACK message from the first terminal.

[0198] The first terminal can generate a registration request message. The first terminal can transmit the generated registration request message to the first NPF through the non-access stratum (NAS) layer and forward it to the access management / association mobility function (AMF) (S650). In this way, the first terminal can request registration from the AMF.

[0199] The NAS layer may be a layer for signaling between the first terminal and the core network, rather than signaling between the first terminal and the first NPT. The first terminal and the core network may perform authentication and security procedures through the NAS layer (S660). The AMF may receive a registration request message from the first terminal via the first NPT. The AMF may register the first terminal according to the received registration request message. The AMF may transmit a registration acceptance message to the first terminal via the first NPT to notify that the registration has been accepted (S670). The first terminal may receive the registration acceptance message from the AMF. The AMF may transmit an RRC reconfiguration message to the first terminal via the first NPT. The first terminal may receive the RRC reconfiguration message from the AMF. The first terminal may perform RRC reconfiguration according to the received RRC reconfiguration message. The first terminal can transmit an RRC reconfiguration completion message to the AMF via the first NPT. The AMF can receive the RRC reconfiguration completion message from the first terminal via the first NPT. The first terminal can transmit a registration completion message to the AMF via the first NPT (S680). The AMF can receive the registration completion message from the first terminal. The first terminal can enter an RRC connected state capable of transmitting and receiving data within the cell.

[0200] The first terminal and AMF can complete faster RRC re-establishment from a physical layer perspective, and perform a registration request procedure, authentication and supplementary procedure, registration acceptance procedure, and registration completion procedure using the NAS layer to transition to a system connected state after transitioning to the system connected state.

[0201] The operations of the method according to the embodiments of the present disclosure can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores information readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0202] Additionally, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0203] While some aspects of the present disclosure have been described in the context of a device, they may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, at least one or more of the most important method steps may be performed by such a device.

[0204] In embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, the field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by some hardware device.

[0205] Although the present disclosure has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present disclosure without departing from the spirit and scope of the present disclosure as set forth in the claims below.

Claims

1. As a terminal method, A step of receiving a first SSB (synchronization signal block) from a first TRP (transmission and reception point); A step of performing downlink synchronization for the first TRP based on the first SSB; A step of receiving a second SSB from a second TRP; A step of performing downlink synchronization for the second TRP based on the second SSB; A step of receiving a SIB (system information block) based on the first SSB from the first TRP; and A step of performing a random access procedure with the first TRP and the second TRP based on the second SSB and / or the SIB, Terminal method.

2. In claim 1, The first SSB and the second SSB include at least one of a first synchronization signal indicating a physical cell identity (PCI) ID (identifier), a second synchronization signal indicating a TRP ID, a third synchronization signal indicating a beam ID, or a physical broadcast channel (PBCH) including a master information block (MIB). Terminal method.

3. In claim 1, The first SSB and the second SSB include at least one of a first synchronization signal indicating a PCI ID, a second synchronization signal indicating a TRP ID, or a PBCH consisting of a beam ID and a master information block. Terminal method.

4. In claim 1, The step of receiving a SIB (system information block) based on the first SSB from the first TRP is as follows: A step of determining the first TRP as a normal TRP based on the first SSB; A step of obtaining a master information block of the first TRP from the first SSB; and A step of receiving the SIB from the first TRP based on the master information block of the first TRP, Terminal method.

5. In claim 1, Further comprising a step of determining the second TRP as a low-power TRP based on the second SSB, The terminal does not attempt to obtain the master information block of the second TRP from the second SSB. Terminal method.

6. In claim 1, The SIB includes information about first time resource(s) and first frequency resource(s) for transmitting a first preamble from the terminal to the first TRP, the second SSB includes a master information block of the second TRP, and the master information block of the second TRP includes information about second time resource(s) and second frequency resource(s) for transmitting a second preamble from the terminal to the second TRP. Terminal method.

7. In claim 6, The step of performing a random access procedure with the first TRP and the second TRP based on the second SSB and the SIB is as follows: A step of obtaining information about the first time resource(s) and the first frequency resource(s) from the SIB; A step of obtaining information about the second time resource(s) and the second frequency resource(s) in the second SSB; and A step of performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s), Terminal method.

8. In claim 7, The step of performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s) is as follows: A step of transmitting the first preamble to a pair of time resources and frequency resources using the first time resource(s) and the second frequency resource(s) as the first TRP; A step of transmitting the second preamble to a pair of time resources and frequency resources as the second TRP using the second time resource(s) and the second frequency resource(s); A step of receiving a first signal including a first response to the first preamble and a second response to the second preamble from the first TRP; A step of transmitting a second signal including a terminal identifier to the first TRP; A step of transmitting a third signal including the terminal identifier to the second TRP; and comprising a step of receiving a fourth signal including a third response to the second signal and a fourth response to the third signal from the first TRP; Terminal method.

9. In claim 7, The step of performing a random access procedure with the first TRP and the second TRP based on the first time resource(s), the second time resource(s), the first frequency resource(s) and the second frequency resource(s) is as follows: A step of transmitting the first preamble to the first TRP using one pair of the first time resource(s) and the first frequency resource(s); A step of transmitting the second preamble to the second TRP using a pair of the second time resource(s) and the second frequency resource(s); A step of receiving a first signal including a first response to the first preamble and an instruction to retransmit the second preamble from the first TRP; A step of retransmitting the second preamble with the second TRP; A step of receiving a second response to the second preamble; A step of transmitting a second signal including a terminal identifier to the first TRP; A step of transmitting a third signal including the terminal identifier to the second TRP; and comprising a step of receiving a fourth signal including a third response to the second signal and a fourth response to the third signal from the first TRP; Terminal method.

10. In claim 1, The above SIB includes information on the transmission power required to transmit a signal from the terminal to the first TRP. Terminal method.

11. In claim 1, The master information block of the second TRP further includes at least one of information indicating the type of TRP, information about SFN (system frame number), information about SCS (subcarrier spacing), or information about transmission power required to transmit a signal from the terminal to the second TRP. Terminal method.

12. In claim 1, A step of performing uplink synchronization for the first TRP through the above random access procedure; and Further comprising a step of performing uplink synchronization for the second TRP through the above random access procedure, The first TRP is a normal TRP, the first TRP is a low-power TRP, the first SSB is a suboptimal SSB, and the second SSB is a best-effort SSB. Terminal method.

13. As a method of the first TRP (transmission and reception point), A step of transmitting to a terminal an SSB (synchronization signal block) including at least one of a first synchronization signal for indicating a PCI (physical cell identity) ID (identifier) ​​or a second synchronization signal for indicating a TRP ID; A step of transmitting a SIB (system information block) to the terminal based on the SSB; A step of performing a random connection procedure with the terminal based on the SIB; and Comprising a step of forming a connection state with the terminal, Method of the 1st TRP.

14. In claim 13, The SSB includes at least one of a third synchronization signal or a physical broadcast channel (PBCH) including a master information block (MIB) that allows the terminal to recognize a beam ID. Method of the 1st TRP.

15. In claim 13, When the first synchronization signal and the second synchronization signal are mapped to the same frequency resource and time resource or when the first synchronization signal and the second synchronization signal are mapped to partially the same frequency resource and time resource, the first synchronization signal and the second synchronization signal are transmitted by element-wise multiplication or element-wise exclusive-OR. Method of the 1st TRP.

16. In claim 13, The step of performing a random connection procedure with the terminal based on the above SIB is: A step of receiving a first preamble from the terminal based on the SIB; A step of receiving a first response to a second preamble transmitted from the terminal to the second TRP from the second TRP; A step of transmitting a first signal including the first response and a second response to the first preamble to the terminal; A step of receiving a second signal including a terminal identifier from the terminal; A step of receiving a third response for the terminal identifier transmitted from the terminal to the second TRP from the second TRP; and A step of transmitting a second signal including a third response and a fourth response to the second signal to the terminal, Method of the 1st TRP.

17. In claim 13, The step of performing a random connection procedure with the terminal based on the above SIB is: A step of receiving a first preamble from the terminal; A step of transmitting a first signal including a first response to the first preamble and an instruction for retransmission of the second preamble to the terminal; A step of receiving a second response to the second preamble from the second TRP; A step of transmitting the second response to the terminal; A step of receiving a second signal including a terminal identifier from the terminal; A step of generating a third response to the second signal; receiving a fourth response to a third signal including the terminal identifier from the second TRP; and A step of transmitting a fourth signal including the third response and the fourth response to the terminal, Method of the 1st TRP.

18. As a method of the second TRP (transmission and reception point), A step of transmitting, to the terminal, an SSB (synchronization signal block) including at least one of information on transmission power for transmitting a signal from the terminal to the second TRP or information on time resource(s) and frequency resource(s) for transmitting a preamble from the terminal to the second TRP; A step of receiving the preamble from the terminal based on the time resource(s) and the frequency resource(s); A step of transmitting a first response to the above preamble to a first TRP; A step of receiving a terminal identifier from the terminal; and comprising the step of transmitting a second response to the terminal identifier to the first TRP; The second TRP method.

19. In claim 18, The above SSB includes at least one of a first synchronization signal indicating a PCI ID (identifier), a second synchronization signal indicating a TRP ID, a third synchronization signal indicating a beam ID, or a physical broadcast channel (PBCH) including a master information block (MIB). The second TRP method.

20. In claim 19, The master information block includes at least one of information about the transmission power for transmitting a signal from the terminal to the second TRP or information about the time resource(s) and the frequency resource(s) for transmitting the preamble from the terminal to the second TRP. The second TRP method.

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