Operating method of apparatus, and apparatus using method

Abstract

An operating method of an apparatus in a wireless communication system, and an apparatus using the method are provided. The apparatus receives, from a base station, SSB position information indicating time domain positions of SSBs transmitted within a half frame, receives a plurality of SSBs at the time domain positions, the respective SSBs including i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH, selects a first SSB from among the plurality of SSBs, transmits a random access signal in the beam direction of the first SSB, receives a random access response in response to the random access signal, the random access response including reflector information indicating whether a reflector is present in a region related to the first SSB, measures a second SSB satisfying a specific condition for beam management when the reflector information indicates that a reflector is present in the region, and transmits information of the second SSB to the base station.

Description

Method of operation of a device and a device using the above method

[0001] The present disclosure relates to a method of operation of a device in a wireless communication system in which a reflector is present, and a device utilizing said method.

[0002] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that consider services / terminals sensitive to reliability and latency are being discussed. Thus, the introduction of next-generation radio access technologies that consider enhanced mobile broadband (eMBB), massive MTC, and Ultra-Reliable and Low Latency Communication (URLC) is being discussed, and for convenience in this disclosure, such technology is referred to as new RAT or NR. NR is also referred to as a fifth-generation (5G) system.

[0003] Meanwhile, a reflector may exist in a wireless communication system. A reflector may be an object that reflects signals transmitted by a transmitter (e.g., a base station) at a specific angle without decoding or encoding them. Since dead zones may occur within a base station's cell coverage due to topographical causes, reflectors may be deployed to enable communication in these dead zones.

[0004] A receiver (e.g., a terminal) may receive a signal directly from a transmitter, but may also receive a signal transmitted by the transmitter through a reflector.

[0005] However, in some cases, the signal strength of the transmitter received through a reflector may be greater than the signal strength received directly from the transmitter.

[0006] For example, when a base station transmits synchronization signals and physical broadcast channel blocks (SSBs) in multiple beam directions, a terminal can transmit a random access channel (RACH) by selecting / using the beam direction of the SSB with the highest received signal received power (RSRP) among these SSBs. At this time, when transmitting the random access channel, the terminal may include or associate information regarding the selected SSB. Then, the base station performs beam management for the terminal based on this RACH.

[0007] However, if the SSB selected by the terminal is an SSB received through a reflector, the direction of the terminal determined by the base station may not match the actual direction of the terminal. Consequently, a problem may arise where the efficiency of beam management for the terminal is reduced.

[0008] The technical problem that the present disclosure aims to solve is to provide a method of operation of a device in a wireless communication system and a device utilizing said method.

[0009] In one aspect, a method of operating the device is provided. The above method is characterized in that a device (e.g., a terminal) receives SSB location information indicating time domain positions of a Synchronization Signal and physical broadcast channel block (SSB) transmitted within a half frame from a base station, receives a plurality of SSBs at the time domain positions, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH), selects a first SSB among the plurality of SSBs, transmits a random access signal in the beam direction of the first SSB, and receives a random access response in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and if the reflector information indicates that there is a reflector in the area, measures a second SSB that satisfies a specific condition for beam management, and transmits information of the second SSB to the base station.

[0010] In another aspect, a device for executing the above method, a computer-readable storage medium, and a chipset are provided.

[0011] In another aspect, a method of operation of a base station is provided. According to the method, SSB location information is transmitted to a terminal, which indicates the time domain locations of SSBs transmitted within a half frame; a plurality of SSBs are transmitted to the terminal at the time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH; a random access signal transmitted by the terminal is received in the beam direction of a first SSB selected by the terminal among the plurality of SSBs; and a random access response is transmitted to the terminal in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB; and based on the reflector information indicating that there is a reflector in the area, a measurement result of a second SSB satisfying a specific condition for beam management is received from the terminal, and beam switching is performed to use the beam direction of the second SSB for communication with the terminal.

[0012] In another aspect, a base station utilizing the above method is provided.

[0013] According to the method of the present disclosure, beam management of a base station can be efficiently performed in a wireless communication system where a reflector is present.

[0014] As a result, communication efficiency between the base station and the terminal can be increased, thereby increasing the system's throughput and improving communication reliability.

[0015] The effects obtainable from the embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by a person skilled in the art to which the technical configuration of the present disclosure applies from the description of the embodiments of the present disclosure below. That is, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived by a person skilled in the art from the embodiments of the present disclosure.

[0016] FIG. 1 illustrates a wireless communication system to which the present disclosure may be applied.

[0017] Figure 2 is a block diagram showing the radio protocol architecture for the user plane.

[0018] Figure 3 is a block diagram showing the wireless protocol structure for the control plane.

[0019] Figure 4 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0020] Figure 5 illustrates the functional partitioning between NG-RAN and 5GC.

[0021] Figure 6 illustrates a frame structure that can be applied in NR.

[0022] Figure 7 illustrates a slot structure.

[0023] Figure 8 illustrates a core set.

[0024] Figure 9 is a diagram showing the difference between the core set in the conventional control area and NR.

[0025] Figure 10 illustrates an example of a frame structure for a new wireless access technology.

[0026] Figure 11 illustrates the structure of a self-contained slot.

[0027] FIG. 12 illustrates physical channels and general signal transmission.

[0028] Figure 13 illustrates a scenario in which three different bandwidth parts are set.

[0029] Figure 14 is an example of the time-frequency structure of an SSB.

[0030] Figure 15 illustrates the structure of a reflector.

[0031] Figure 16 illustrates a different structure of a reflector.

[0032] Figure 17 shows an example of a terminal receiving a signal in an environment with a reflector.

[0033] Figure 18 shows an example of operation between a base station and a terminal.

[0034] FIG. 19 illustrates a method of operation of a terminal according to one embodiment of the present disclosure.

[0035] FIG. 20 illustrates a wireless device that can be applied to the present specification.

[0036] Figure 21 illustrates an example of a signal processing module structure.

[0037] Figure 22 illustrates another example of a signal processing module structure within a transmission device.

[0038] FIG. 23 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0039] Figure 24 illustrates another example of a wireless device.

[0040] FIG. 25 illustrates a communication system (1) applicable to the present specification.

[0041] In this specification, the symbols / abbreviations / terms used are as follows.

[0042] BS: base station,

[0043] UE: User Equipment,

[0044] DCI: Downlink Control Information,

[0045] SSB: Synchronization signal block,

[0046] PBCH: Physical Broadcasting Channel,

[0047] RACH: Random access channel,

[0048] RIS: reflecting intelligent surfaces,

[0049] RAPID: RandomAccessPreambleID.

[0050] FIG. 1 illustrates a wireless communication system to which the present disclosure may be applied. This may also be referred to as an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) or an LTE (Long Term Evolution) / LTE-A system.

[0051] E-UTRAN includes a base station (20: Base Station, BS) that provides a control plane and a user plane to a terminal (10: User Equipment, UE). The terminal (10) may be fixed or mobile and may be referred to by other terms such as MS (Mobile station), UT (User Terminal), SS (Subscriber Station), MT (mobile terminal), Wireless Device, or terminal. The base station (20) refers to a fixed station that communicates with the terminal (10) and may be referred to by other terms such as eNB (evolved-NodeB), BTS (Base Transceiver System), Access Point, or gNB.

[0052] Base stations (20) can be connected to each other through an X2 interface. The base station (20) is connected to the EPC (Evolved Packet Core, 30) through the S1 interface, more specifically to the MME (Mobility Management Entity) through the S1-MME and to the S-GW (Serving Gateway) through the S1-U.

[0053] The EPC (30) consists of an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME holds information regarding the terminal's connection information or capabilities, and this information is primarily used for managing the terminal's mobility. The S-GW is a gateway with an E-UTRAN as its endpoint, and the P-GW is a gateway with a PDN as its endpoint.

[0054] The layers of the Radio Interface Protocol between a terminal and a network can be classified into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. Among these, the physical layer, which belongs to Layer 1, provides information transfer services using a physical channel, while the Radio Resource Control (RRC) layer, located at Layer 3, performs the role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0055] FIG. 2 is a block diagram showing the radio protocol architecture for the user plane. FIG. 3 is a block diagram showing the radio protocol architecture for the control plane. The user plane is a protocol stack for transmitting user data, and the control plane is a protocol stack for transmitting control signals.

[0056] Referring to Figures 2 and 3, the physical layer (PHY layer) provides information transfer services to upper layers using a physical channel. The physical layer is connected to the upper layer, the MAC (Medium Access Control) layer, through a transport channel. Data travels between the MAC layer and the physical layer through the transport channel. Transport channels are classified according to how and with what characteristics data is transmitted through a wireless interface.

[0057] Data travels between different physical layers, specifically between the physical layers of the transmitter and the receiver, through a physical channel. This physical channel can be modulated using the Orthogonal Frequency Division Multiplexing (OFDM) method and utilizes time and frequency as wireless resources.

[0058] The functions of the MAC layer include mapping between logical channels and transport channels, and multiplexing / demultiplexing MAC SDUs (service data units) belonging to logical channels into transport blocks provided to physical channels over the transport channel. The MAC layer provides services to the RLC (Radio Link Control) layer through logical channels.

[0059] The functions of the RLC layer include the concatenation, segmentation, and reassembly of RLC SDUs. To ensure the various Quality of Service (QoS) required by Radio Bearers (RBs), the RLC layer provides three operating modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through Automatic Repeat Requests (ARQ).

[0060] The RRC (Radio Resource Control) layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in relation to the configuration, reconfiguration, and release of wireless bearers. RB refers to a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a terminal and a network.

[0061] The functions of the PDCP (Packet Data Convergence Protocol) layer in the user plane include the delivery of user data, header compression, and ciphering. The functions of the PDCP (Packet Data Convergence Protocol) layer in the control plane include the delivery of control plane data and encryption / integrity protection.

[0062] The establishment of an RB refers to the process of defining the characteristics of the wireless protocol layer and channel to provide specific services, and setting their respective specific parameters and operating methods. RBs can be further divided into two types: SRBs (Signaling RBs) and DRBs (Data RBs). SRBs are used as a channel for transmitting RRC messages in the control plane, while DRBs are used as a channel for transmitting user data in the user plane.

[0063] When an RRC connection is established between the terminal's RRC layer and the E-UTRAN's RRC layer, the terminal is in an RRC connected state; otherwise, it is in an RRC idle state.

[0064] Downlink transmission channels for transmitting data from a network to a terminal include a Broadcast Channel (BCH) for transmitting system information and a Shared Channel (SCH) for transmitting user traffic or control messages. Traffic or control messages for downlink multicast or broadcast services may be transmitted via the Shared Channel (SCH) or via a separate Multicast Channel (MCH). Meanwhile, uplink transmission channels for transmitting data from a terminal to a network include a Random Access Channel (RACH) for transmitting initial control messages and a Shared Channel (SCH) for transmitting user traffic or control messages.

[0065] Logical channels that are above the transmission channel and map to the transmission channel include BCCH (Broadcast Control Channel), PCCH (Paging Control Channel), CCCH (Common Control Channel), MCCH (Multicast Control Channel), and MTCH (Multicast Traffic Channel).

[0066] A physical channel consists of multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A single subframe consists of multiple OFDM symbols in the time domain. A resource block is a resource allocation unit composed of multiple OFDM symbols and multiple subcarriers. Additionally, each subframe may utilize specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) within that subframe for a Physical Downlink Control Channel (PDCCH), e.g., an L1 / L2 control channel. The Transmission Time Interval (TTI) is the unit time for subframe transmission.

[0067] The following describes new radio access technology (new RAT, NR).

[0068] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, Massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that take into account services and terminals sensitive to reliability and latency are being discussed. Thus, the introduction of next-generation radio access technologies that consider enhanced mobile broadband communication, massive MTC, and Ultra-Reliable and Low Latency Communication (URLC) is being discussed, and for convenience, this technology is referred to as new RAT or NR in this disclosure.

[0069] Figure 4 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0070] Referring to FIG. 4, the NG-RAN may include gNBs and / or eNBs that provide user plane and control plane protocol termination to terminals. FIG. 4 illustrates a case where only gNBs are included. The gNBs and eNBs are connected to each other via Xn interfaces. The gNBs and eNBs are connected to the 5G Core Network (5GC) via NG interfaces. More specifically, they are connected to the access and mobility management function (AMF) via NG-C interfaces and to the user plane function (UPF) via NG-U interfaces.

[0071] Figure 5 illustrates the functional partitioning between NG-RAN and 5GC.

[0072] Referring to FIG. 5, the gNB can provide functions such as Inter Cell RRM, RB control, Connection Mobility Control, Radio Admission Control, Measurement Configuration & Provision, and Dynamic Resource Allocation. The AMF can provide functions such as NAS security and idle state mobility processing. The UPF can provide functions such as Mobility Anchoring and PDU processing. The SMF (Session Management Function) can provide functions such as terminal IP address allocation and PDU session control.

[0073] Figure 6 illustrates a frame structure that can be applied in NR.

[0074] Referring to FIG. 6, radio frames (hereinafter abbreviated as frames) may be used for uplink and downlink transmission in NR. A frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). A half-frame can be defined as five 1 ms subframes (SF). A subframe can be divided into one or more slots, and the number of slots within a subframe depends on the subcarrier spacing (SCS). Each slot contains 12 or 14 OFDM(A) symbols according to the cyclic prefix (CP). When a normal CP is used, each slot contains 14 symbols. When an extended CP is used, each slot contains 12 symbols. Here, the symbols may include OFDM symbols (or CP-OFDM symbols) or SC-FDMA symbols (or DFT-s-OFDM symbols).

[0075] The following Table 1 shows examples of subcarrier spacing configurations μ.

[0076] [Table 1]

[0077]

[0078] Table 2 below shows the number of slots (N) within a frame according to the subcarrier spacing configuration μ. frame,μ slot ), number of slots in the subframe (N subframe,μ slot ), number of symbols in the slot (N slot symb Examples include ) etc.

[0079] [Table 2]

[0080]

[0081] Figure 6 illustrates μ=0, 1, 2, and 3.

[0082] Table 2-1 below illustrates how the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS when an extended CP is used (μ= 2, 60KHz).

[0083] [Table 2-1]

[0084]

[0085] In an NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) can be configured differently among multiple cells merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) composed of the same number of symbols can be configured differently among the merged cells.

[0086] Figure 7 illustrates a slot structure.

[0087] A slot may contain multiple symbols in the time domain. For example, in the case of a normal CP, one slot may contain 14 symbols (or 7 symbols), but in the case of an extended CP, one slot may contain 12 symbols (or 6 symbols). A carrier may contain multiple subcarriers in the frequency domain. A Resource Block (RB) may be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) may be defined as multiple consecutive (P)RBs in the frequency domain and may correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier may contain up to N (e.g., 4 or 5) BWPs. Data communication is performed through the active BWP, and only one BWP may be active for a single terminal. In a resource grid, each element is referred to as a Resource Element (RE), and a single complex symbol can be mapped to it. A mini-slot can consist of, for example, 2, 4, or 7 symbols.

[0088] The PDCCH (physical downlink control channel) can be composed of one or more CCEs (control channel elements) as shown in Table 3 below.

[0089] [Table 3]

[0090]

[0091] For example, a PDCCH can be transmitted through a resource consisting of 1, 2, 4, 8, or 16 CCEs. Here, a CCE consists of 6 REGs (resource element groups), and one REG consists of one resource block in the frequency domain and one OFDM (orthogonal frequency division multiplexing) symbol in the time domain.

[0092] Monitoring means decoding each PDCCH candidate according to the DCI (downlink control information) format. The terminal monitors a set of PDCCH candidates in one or more core sets (CORESET, described below) on the active DL BWP of each active serving cell where PDCCH monitoring is configured, according to the corresponding set of search spaces.

[0093] In NR, a new unit called a control resource set (CORESET) can be introduced. A terminal can receive PDCCH from the core set.

[0094] Figure 8 illustrates a core set.

[0095] Referring to Fig. 8, the core set is N in the frequency domain. CORESET RB It consists of N resource blocks, and in the time domain N CORESET symb ∈ Can be composed of {1, 2, 3} symbols. N CORESET RB , N CORESET symbIt can be provided by the base station through an upper layer signal. As illustrated in FIG. 8, a core set may include a plurality of CCEs (or REGs). A single CCE may be composed of a plurality of REGs (resource element groups), and a single REG may include one OFDM symbol in the time domain and 12 resource elements in the frequency domain.

[0096] The terminal can attempt to detect PDCCH in units of 1, 2, 4, 8, or 16 CCEs within the core set. One or more CCEs that can attempt to detect PDCCH may be called PDCCH candidates.

[0097] The terminal can be configured with multiple core sets.

[0098] Figure 9 is a diagram showing the difference between the core set in the conventional control area and NR.

[0099] Referring to FIG. 9, the control area (800) in a conventional wireless communication system (e.g., LTE / LTE-A) is configured across the entire system band used by the base station. All terminals, except for some terminals that support only a narrow band (e.g., eMTC / NB-IoT terminals), had to be able to receive wireless signals across the entire system band of the base station in order to properly receive / decode control information transmitted by the base station.

[0100] On the other hand, in NR, the aforementioned core sets are introduced. The core sets (801, 802, 803) can be described as wireless resources for control information that a terminal must receive, and only a portion of the system band can be used instead of the entire system band in the frequency domain. Additionally, only some of the symbols within a slot can be used in the time domain. A base station can assign a core set to each terminal and transmit control information through the assigned core set. For example, in FIG. 9, the first core set (801) can be assigned to terminal 1, the second core set (802) can be assigned to terminal 2, and the third core set (803) can be assigned to terminal 3. In NR, a terminal can receive control information from a base station even without necessarily receiving the entire system band.

[0101] A core set may include a terminal-specific core set for transmitting terminal-specific control information and a common core set for transmitting control information common to all terminals.

[0102] Meanwhile, in NR, high reliability may be required depending on the application field, and in such situations, the target block error rate (BLER) for downlink control information (DCI) transmitted through a downlink control channel (e.g., physical downlink control channel: PDCCH) can be significantly lower than that of conventional technology. As an example of a method to satisfy such requirements for high reliability, the amount of content included in the DCI can be reduced, and / or the amount of resources used during DCI transmission can be increased. In this case, the resources may include at least one of resources in the time domain, resources in the frequency domain, resources in the code domain, and resources in the space domain.

[0103] The following technologies / features can be applied in NR.

[0104] Self-contained subframe structure

[0105] Figure 10 illustrates an example of a frame structure for a new wireless access technology.

[0106] In NR, for the purpose of minimizing latency, a structure in which the control channel and the data channel are time-division multiplexed (TDM) within a single TTI, as shown in Fig. 10, can be considered as one of the frame structures.

[0107] Figure 10 illustrates an example in which a downlink control area is located at the front of the TTI and an uplink control area is located at the back of the TTI. The area between the downlink control area and the uplink control area may be used for transmitting downlink data (DL data) or for transmitting uplink data (UL data). A characteristic of this structure is that downlink (DL) reception and uplink (UL) transmission proceed sequentially within a single subframe / slot, allowing DL data to be received and UL ACK / NACK (Acknowledgement / Not-acknowledgement) to be transmitted within a single subframe / slot. Consequently, the time required for data retransmission in the event of a data transmission error is reduced, thereby minimizing the latency of the final data delivery.

[0108] In such a data and control TDMed subframe structure, a time gap is required for the transition process between the base station and the terminal from transmit mode to receive mode or from receive mode to transmit mode. To this end, in a self-contained subframe structure, some OFDM symbols at the time of transition from DL to UL can be set as a guard period (GP).

[0109] Figure 11 illustrates the structure of a self-contained slot.

[0110] In an NR system, a single slot may contain a DL control channel, DL or UL data, a UL control channel, etc. For example, the first N symbols within the slot may be used to transmit a DL control channel (hereinafter referred to as the DL control area), and the last M symbols within the slot may be used to transmit a UL control channel (hereinafter referred to as the UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as the data area) located between the DL control area and the UL control area may be used for transmitting DL data or for transmitting UL data. As an example, the following configuration may be considered. Each section is listed in chronological order.

[0111] 1. DL only configuration

[0112] 2. UL only configuration

[0113] 3. Mixed UL-DL Configuration

[0114] - DL Area + GP (Guard Period) + UL Control Area

[0115] - DL Control Area + GP + UL Area

[0116] DL Area: (i) DL Data Area, (ii) DL Control Area + DL Data Area

[0117] UL Area: (i) UL Data Area, (ii) UL Data Area + UL Control Area

[0118] In the DL control area, PDCCH can be transmitted, and in the DL data area, PDSCH (physical downlink shared channel) can be transmitted. In the UL control area, PUCCH (physical uplink control channel) can be transmitted, and in the UL data area, PUSCH (physical uplink shared channel) can be transmitted. In PDCCH, DCI (Downlink Control Information), such as DL data scheduling information and UL data scheduling information, can be transmitted. In PUCCH, UCI (Uplink Control Information), such as ACK / NACK (Positive Acknowledgement / Negative Acknowledgement) information for DL ​​data, CSI (Channel State Information) information, and SR (Scheduling Request), can be transmitted. GP provides a time gap during the process of the base station and the terminal switching from transmit mode to receive mode or from receive mode to transmit mode. Within a subframe, some symbols at the point of transition from DL to UL can be set as GP.

[0119] Analog Beamforming #1

[0120] In millimeter wave (mmW), the shorter wavelength allows for the installation of multiple antenna elements within the same area. Specifically, in the 30 GHz band, the wavelength is 1 cm, making it possible to install a total of 100 antenna elements in a 2-dimensional array form with a spacing of 0.5 wavelengths (lambda) on a 5 by 5 cm panel. Therefore, in mmW, multiple antenna elements are used to increase beamforming (BF) gain, thereby increasing coverage or throughput.

[0121] In this case, if a transceiver unit (TXRU) is equipped to allow for transmission power and phase control for each antenna element, independent beamforming for each frequency resource becomes possible. However, installing TXRUs for all 100 or so antenna elements presents a problem of low cost-effectiveness. Therefore, a method is being considered in which multiple antenna elements are mapped to a single TXRU and the beam direction is adjusted using an analog phase shifter. This analog beamforming method has the disadvantage of being unable to perform frequency-selective beamforming because it can only create a single beam direction across the entire band.

[0122] A hybrid beamforming (hybrid BF) can be considered as an intermediate form between digital beamforming (Digital BF) and analog beamforming (analog BF), having B TXRUs, which is fewer than Q antenna elements. In this case, although there are differences depending on the connection method between B TXRUs and Q antenna elements, the number of beam directions that can be transmitted simultaneously is limited to B or fewer.

[0123] Analog Beamforming #2

[0124] In NR systems, when multiple antennas are used, hybrid beamforming techniques combining digital and analog beamforming are emerging. In this case, analog beamforming (or RF beamforming) performs precoding (or combining) at the RF stage, which has the advantage of achieving performance close to that of digital beamforming while reducing the number of RF chains and D / A (or A / D) converters. For convenience, the above hybrid beamforming structure can be represented by N TXRUs and M physical antennas. Then, digital beamforming for L data layers to be transmitted at the transmitter can be represented by an N by L matrix, and subsequently, the converted N digital signals pass through the TXRUs to be converted into analog signals, after which analog beamforming represented by an M by N matrix is ​​applied.

[0125] System information of the NR system can be transmitted via broadcasting. In this case, analog beams belonging to different antenna panels within a single symbol can be transmitted simultaneously, and a method is being discussed to introduce a Beam Reference Signal (BRS), which is a reference signal (RS) transmitted by applying a single analog beam (corresponding to a specific antenna panel) to measure the channel for each analog beam. The BRS can be defined for multiple antenna ports, and each antenna port of the BRS can correspond to a single analog beam. In this case, unlike the BRS, the synchronization signal or xPBCH can be transmitted by applying all analog beams within an analog beam group so that any terminal can receive it well.

[0126] In NR, the synchronization signal block (SSB, or may also be referred to as the synchronization signal and physical broadcast channel: SS / PBCH) in the time domain may consist of four OFDM symbols numbered in ascending order from 0 to 3 within the synchronization signal block, and the PBCH associated with the primary synchronization signal (PSS), secondary synchronization signal (SSS), and demodulation reference signal (DMRS) may be mapped to the symbols. As previously mentioned, the synchronization signal block may also be referred to as the SS / PBCH block.

[0127] In NR, multiple synchronization signal blocks can be transmitted at different times, and since an SSB can be used to perform initial access (IA), serving cell measurement, etc., it is desirable for the SSB to be transmitted first when transmission times and resources overlap with other signals. To this end, the network can broadcast the transmission time and resource information of the SSB or indicate it through UE-specific RRC signaling.

[0128] In NR, beam-based transmission and reception operations can be performed. If the reception performance of the current serving beam deteriorates, a process to find a new beam can be performed through a process called beam failure recovery (BFR).

[0129] Since BFR is not a process that declares an error or failure regarding the link between the network and the terminal, it can be assumed that the connection with the current serving cell is maintained even when the BFR process is performed. During the BFR process, measurements are taken on different beams configured by the network (beams can be expressed as CSI-RS ports or SSB (synchronization signal block) indices, etc.), and the best beam for the terminal can be selected. The terminal can proceed with the BFR process by performing the RACH process associated with the beam for which the measurement results are good.

[0130] Now, the Transmission Configuration Indicator (TCI) state is described. The TCI state can be configured per core set of the control channel, and parameters for determining the reception (Rx) beam of the terminal can be determined based on the TCI state.

[0131] For each downlink bandwidth portion (DL BWP) of a serving cell, the terminal may be configured with three or fewer core sets. Additionally, for each core set, the terminal may be provided with the following information.

[0132] 1) Coreset index p (e.g., one of 0 to 11, in which case the index of each coreset can be uniquely determined in the BWPs of a single serving cell),

[0133] 2) PDCCH DM-RS Scrambled Sequence Initialization Value,

[0134] 3) Interval of the core set in the time domain (can be given in symbol units),

[0135] 4) Resource block set,

[0136] 5) CCE-to-REG mapping parameters,

[0137] 6) Antenna port quasi-co-location (QCL) representing the quasi-co-location information of the DM-RS antenna port for PDCCH reception in each core set (from the set of antenna port quasi-co-locations provided by the upper layer parameter called 'TCI-State'),

[0138] 7) Indication of the existence or non-existence of a transmission configuration indication (TCI) field for a specific DCI format transmitted by PDCCH in the core set, etc.

[0139] QCL is explained. If the characteristics of the channel through which a symbol on one antenna port is transmitted can be inferred from the characteristics of the channel through which a symbol on another antenna port is transmitted, then the two antenna ports can be said to be in a quasi-common location (QCL). For example, if two signals (A and B) are transmitted from the same transmission antenna array with the same / similar spatial filter applied, the two signals may experience the same / similar channel conditions. From the perspective of a receiver, if it receives one of the two signals, it can detect the other signal by utilizing the channel characteristics of the received signal.

[0140] In this sense, the fact that A and B are QCL implies that A and B have undergone similar channel conditions, and therefore, the channel information estimated to detect A may also be useful for detecting B. Here, channel conditions can be defined by, for example, Doppler shift, Doppler spread, average delay, delay spread, spatial reception parameters, etc.

[0141] The 'TCI-State' parameter associates one or two downlink reference signals with the corresponding QCL type (QCL types A, B, C, and D exist; see Table 4).

[0142] [Table 4]

[0143]

[0144] Each 'TCI-State' may include parameters for establishing a quasi-common location (QCL) relationship between one or two downlink reference signals and the DM-RS port of the PDSCH (or PDCCH) or the CSI-RS port of the CSI-RS resource.

[0145] Meanwhile, in each DL BWP configured for the terminal in a single serving cell, the terminal may be provided with 10 or fewer search space sets. For each search space set, the terminal may be provided with at least one of the following information.

[0146] 1) search space set index s (0≤s<40), 2) association between core set P and search space set s, 3) PDCCH monitoring period and PDCCH monitoring offset (in slots), 4) PDCCH monitoring pattern within a slot (e.g., indicating the first symbol of the core set within the slot for PDCCH monitoring), 5) number of slots in which search space set s exists, 6) number of PDCCH candidates per CCE aggregation level, 7) information indicating whether search space set s is CSS or USS, etc.

[0147] In NR, core set #0 can be configured by the PBCH (or terminal-specific signaling for handover, PSCell configuration, or BWP configuration). The search space (SS) set #0 configured by the PBCH may have different monitoring offsets (e.g., slot offset, symbol offset) for each associated SSB. This may be necessary to minimize the search space occasions that the terminal needs to monitor. Alternatively, it may be necessary to provide a beam sweeping control / data area capable of transmitting control / data according to each beam, so that communication with the terminal can be maintained even when the terminal's best beam changes dynamically.

[0148] FIG. 12 illustrates physical channels and general signal transmission.

[0149] Referring to FIG. 12, in a wireless communication system, a terminal receives information from a base station via a downlink (DL) and transmits information to the base station via an uplink (UL). The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information they transmit and receive.

[0150] When the power is turned on again after being off, or when a terminal newly enters a cell, it performs an initial cell search operation, such as synchronizing with the base station (S11). To do this, the terminal receives PSCH (Primary Synchronization Channel) and SSCH (Secondary Synchronization Channel) from the base station to synchronize with the base station and obtain information such as cell ID (cell identity). In addition, the terminal can obtain cell broadcast information by receiving PBCH (Physical Broadcast Channel) from the base station. Furthermore, during the initial cell search phase, the terminal can check the downlink channel status by receiving DL RS (Downlink Reference Signal).

[0151] After completing the initial cell search, the terminal can obtain more specific system information by receiving the PDCCH (Physical Downlink Control Channel) and the corresponding PDSCH (Physical Downlink Control Channel) (S12).

[0152] Subsequently, the terminal may perform a Random Access Procedure to complete the connection to the base station (S13~S16). Specifically, the terminal transmits a preamble through a PRACH (Physical Random Access Channel) (S13) and receives a RAR (Random Access Response) for the preamble through a PDCCH and a corresponding PDSCH (S14). Subsequently, the terminal transmits a PUSCH (Physical Uplink Shared Channel) using scheduling information within the RAR (S15) and may perform a Conflict Resolution Procedure such as a PDCCH and a corresponding PDSCH (S16).

[0153] A terminal that has performed the procedure described above may subsequently perform PDCCH / PDSCH reception (S17) and PUSCH / PUCCH (Physical Uplink Control Channel) transmission (S18) as a general uplink / downlink signal transmission procedure. The control information transmitted by the terminal to the base station is referred to as UCI (Uplink Control Information). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is generally transmitted via PUCCH, but it may be transmitted via PUSCH if control information and data need to be transmitted simultaneously. Additionally, the terminal may transmit UCI non-periodically via PUSCH in response to requests / instructions from the network.

[0154] To enable reasonable battery consumption when BA (bandwidth adaptation) is configured, only one uplink BWP and one downlink BWP or only one downlink / uplink BWP pair for each uplink carrier can be enabled at a time within an active serving cell, and all other BWPs configured in the terminal are disabled. In the disabled BWPs, the terminal does not monitor the PDCCH and does not transmit on the PUCCH, PRACH, and UL-SCH.

[0155] Regarding the BA, the terminal's receive and transmit bandwidths do not need to be as wide as the cell's bandwidth and can be adjusted: the width can be commanded to change (e.g., contracting during periods of low activity to save power), the position in the frequency domain can be shifted (e.g., to increase scheduling flexibility), and the subcarrier spacing can be commanded to change (e.g., to allow different services). A subset of the cell's total cell bandwidth is referred to as the bandwidth part (BWP), and the BA is obtained by setting the BWP(s) to the terminal and informing the terminal of which of the set BWPs is currently active. Once the BA is set, the terminal only needs to monitor the PDCCH on one active BWP. For example, there is no need to monitor the PDCCH across the cell's entire downlink frequency. A BWP inactive timer (independent of the aforementioned DRX inactive timer) is used to switch an active BWP to a default BWP: the timer is restarted when PDCCH decoding is successful, and when the timer expires, switching to a default BWP occurs.

[0156] Figure 13 illustrates a scenario in which three different bandwidth parts are set.

[0157] FIG. 13 illustrates an example in which BWP1, BWP2, and BWP3 are configured on time-frequency resources. BWP1 may have a width of 40 MHz and a subcarrier spacing of 15 kHz, BWP2 may have a width of 10 MHz and a subcarrier spacing of 15 kHz, and BWP3 may have a width of 20 MHz and a subcarrier spacing of 60 kHz. In other words, each of the bandwidth parts may have a different width and / or a different subcarrier spacing.

[0158] Figure 14 is an example of the time-frequency structure of an SSB.

[0159] Referring to FIG. 14, the Synchronization Signal and PBCH block (SSB) may include i) primary and secondary synchronization signals (PSS, SSS) each occupying 1 symbol and 127 subcarriers, and ii) a PBCH consisting of 1 symbol that spans 3 OFDM symbols and 240 subcarriers but leaves a portion in the middle (e.g., OFDM symbol 2) unused for the SSS.

[0160] The possible time position of an SSB within a half frame can be determined by subcarrier spacing, and the period of the half frame in which the SSB is transmitted can be set by the network. During the half frame, different SSBs can be transmitted in different spatial directions (e.g., using different beams across the cell's coverage area).

[0161] Multiple SSBs can be transmitted within the frequency span of a single carrier. Different SSBs in the frequency domain may have different physical cell identities (PCI). If an SSB is associated with the Remaining Minimum System Information (RMSI), that SSB may be referred to as a Cell-Defining SSB (CD-SSB). A primary cell (PCell) can always be associated with a CD-SSB located in the synchronization raster.

[0162] If a specific SSB is not associated with or related to RMSI, the specific SSB may be referred to as a non-cell defining SSB (NCD-SSB), and can be used to perform measurements for Radio Link Monitoring (RLM), Beam Failure Detection (BFD), and radio resource management (RRM) measurements, as well as Random Access (RA) resource selection, within an active DL BWP when a CD-SSB is not included in the active BWP. When at most one SSB (CD-SSB or NCD-SSB) is configured in each BWP, the terminal may be configured with multiple SSBs.

[0163] Polar coding may be used for PBCH. Unless the network configures the terminal to assume a different subcarrier spacing, the terminal may assume a band-specific subcarrier spacing for the SSB. PBCH symbols carry its own frequency-multiplexed DMRS. Quadrature Phase Shift Keying (QPSK) modulation may be used for PBCH.

[0164] Cell search is a procedure in which a terminal acquires time and frequency synchronization with a cell and detects the cell ID (identity) of that cell. Cell search can be based on primary and secondary synchronization signals and the PBCH DMRS in the synchronization raster.

[0165] The master information block (MIB) of the PBCH provides the terminal with parameters for PDCCH monitoring (e.g., CORESET#0 setting) for scheduling the PDSCH that transmits the system information block 1 (SIB1).

[0166] System information (SI) consists of MIBs and various SIBs, which can be divided into Minimum SI and Other SI.

[0167] The minimum SI contains basic information required for initial access and information for acquiring other SIs, and the minimum SI may include MIB and SIB1. i) The MIB contains cell forbidden status information and essential physical layer information of the cell required to receive additional system information (e.g., CORESET#0 configuration). The MIB is broadcast periodically on the BCH. ii) SIB1 defines the scheduling of other system information blocks and contains information required for initial access. SIB1 is also called the residual minimum SI (RMSI) and is broadcast periodically on the DL-SCH or transmitted exclusively on the DL-SCH to terminals in the RRC connected state (RRC_CONNECTED).

[0168] Other SIs include all SIBs that are not broadcast in the minimum SI. These SIBs may be broadcast periodically in the DL-SCH, broadcast on demand in the DL-SCH (i.e., at the request of a terminal in the RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED state), or transmitted in a dedicated manner in the DL-SCH to a terminal in the RRC_CONNECTED state.

[0169] The PBCH may indicate that there is no associated SIB1, in which case it informs the terminal of other frequencies where it can search for an SSB associated with SIB1, and also informs the frequency range where it can be assumed that there is no SSB associated with SIB1.

[0170] A terminal in an RRC-connected state can measure multiple beams (one or more) of a cell and derive cell quality by averaging the measurement results (power values). Filtering can be performed at two levels: the physical layer for deriving beam quality and the RRC layer for deriving cell quality from multiple beams. Cell quality based on beam measurements can be derived in the same way for serving cells and non-serving cells. The terminal can report measurement results for X optimal beams to the base station if configured by the base station. The beam measurements to be included in the measurement report can be configured by the network. For example, it can be configured to report including only the beam identifier, to report including both the measurement result and the beam identifier, or to not report beams at all.

[0171] Below, a beam management method for environments where a reflector is present is described.

[0172] For example, according to the method of the present disclosure, when a beam received from a reflector (e.g., reflecting intelligent surfaces: RIS, Intelligent reflecting surfaces: IRS) or a network-controlled repeater (NCR)) and a beam received from a network (e.g., a base station) are measured by a terminal during an initial access procedure, the base station is notified that multiple beams have been measured and is able to set an appropriate beam.

[0173] A reflector may refer to an object / unit that serves the role of reflecting signals transmitted by a base station at a specific angle without decoding or encoding them, such as RIS or NCR.

[0174] For example, dead zones may occur within a base station's cell coverage due to topographical causes, and reflectors can be utilized to enable communication even in these dead zones.

[0175] Since the reflector cannot perform encoder and decoder operations, the beam index for the beams that the reflector can operate on must depend on the beam index transmitted by the base station.

[0176] In the following, reflectors are limited to cases where they are stationary and immobile, and it is assumed that the base station knows the spatial location of the reflector (e.g., RIS, NCR). Alternatively, even if the spatial location of the reflector is unknown, it is assumed that the base station knows information that a reflector exists in a specific space in units of the SSB beam indices operated by the base station. For example, when the SSB beam indices of the SSB beams operated by the base station are #1 to #4, it is assumed that the base station knows in advance that there is a reflector in the beam direction of SSB beam index #3.

[0177] Figure 15 illustrates the structure of a reflector.

[0178] Referring to FIG. 15, the reflector may be composed of a combiner that combines signals between a receiving antenna (Rx antenna) and a transmitting antenna (Tx antenna), a divider, and a phased array element that forms a receiving (Rx) beam and a transmitting (Tx) beam.

[0179] Since the reflector (e.g., RIS) is made of passive elements, the direction of the receiving beam and the transmitting beam cannot be steered, and the beam is formed in one direction.

[0180] Figure 16 illustrates a different structure of a reflector.

[0181] Referring to FIG. 16, the reflector may include a controller and a plate.

[0182] The substrate can be made of a material with specific reflective properties, such as a meta surface or a mirror. The controller can control the reflection coefficient of the material.

[0183] The substrate can be passive, in which case the reflection angle is fixed, and it can be assumed that the amplitude reflection coefficient is fixed to obtain a maximum power radio signal.

[0184] Path loss, also known as propagation path loss, can be expressed by the formula Pathloss = 'FreeSpacePathLoss' + 10log(d) + AT[dB] + 'shadow fading'.

[0185] Here, 'FreeSpacePathLoss' increases with the center frequency—for example, the frequency used—and also increases with distance. It is evident that THz communication is more vulnerable to propagation path loss than mmWave or LTE. In wireless communication environments with severe propagation path loss, methods to overcome this are being considered, such as maximizing beam gain by configuring the transmit and receive ends with a very large number of antenna elements.

[0186] In order to simulate a more realistic environment based on propagation path loss, the path loss between the base station, the reflector (RIS), and the terminal can be derived using the following equation based on the 'Urban micro cell street canyon model'.

[0187] [Equation 1]

[0188]

[0189] In the above equation, P bs is the base station's transmission power, and G bs is the base station's antenna gain, G ris is the receiving antenna gain of the reflector (RIS), G ue represents the receiving antenna gain of the terminal. 'NoiseFigure' and 'Evm level', 'fading', 'interference', and 'implementation margin' are parameters associated with the terminal. D bs_ris represents the distance between the base station and the reflector (RIS), and h bs is the height at which the base station is installed, h ris is the location where the reflector (RIS) is installed, d bp means break point.

[0190] The free space based path loss due to the substrate can be calculated using the following Equation 2. Here, the signal's range is limited to within the far field.

[0191] [Equation 2]

[0192]

[0193] In the above equation, (a) represents normalization, and in the equation after normalization, d1 represents the distance between the base station and the reflector, and d2 represents the distance between the reflector and the terminal, (MNd x d y ) 2 is the size of the substrate, cosθ t , cosθ r represents the receiving angle and transmitting angle of the reflector, respectively, and A represents the amplitude reflection coefficient.

[0194] One objective of the present disclosure is to enable a base station to determine whether the terminal is aligning a beam from a reflector (RIS) or a line of sight (LoS) beam from the base station.

[0195] In configuring antenna elements, the base station can transmit signals by configuring antenna elements based on the minimum received SNR value that allows receiving SSB within cell coverage without considering reflectors (e.g., RIS, hereinafter the same).

[0196] Figure 17 shows an example of a terminal receiving a signal in an environment with a reflector.

[0197] Referring to Figure 17, a simulation was performed based on the premise that at least 4*2 antenna elements are required when transmitting a signal with a base station cell coverage of 1000 meters and a transmission (Tx) power of 36 dBm.

[0198] Let's assume there is a shadow area outside the base station cell that a reflector must cover. In this case, the signal strength reflected through the reflector must be greater than or equal to the signal strength at which the terminal can receive the SSB.

[0199] The signal received from the base station plus the gain of the reflector can be assumed to be the transmission power of the reflector, and as the number of antenna elements in the reflector increases (or the size increases), additional gain can be secured in the reflector.

[0200] For example, assuming the coverage of the reflector is 200 meters, the number of antenna elements required for the reflector could be 16*32.

[0201] In this environment, a terminal (UE) located 1,000 meters away from a base station can receive a beam with an SSB index of 4 directly from the base station, and receive a beam with an SSB index of 1 through a reflector.

[0202] In this case, according to simulations, the RSRP of the beam with SSB index 1 received through the reflector may, in some instances, be greater than the RSRP of the beam with SSB index 4 received directly from the base station. Consequently, there is a possibility that the terminal may align with the beam received through the reflector, and in the area where the base station's coverage and the reflector's coverage overlap, the base station is more likely to perform incorrect beam management for the terminal (of course, a method could also be considered where the number of antenna elements in the reflector is set low so that the terminal always aligns with the beam received directly from the base station. However, in this case, the terminal cannot expect additional gain from the reflector, and the throughput within the reflector will remain at a very low level).

[0203] That is, if a terminal (the receiving end) receives the 4th SSB beam (a beam with an SSB index of 4) directly from the base station, and then receives the 1st SSB beam (a beam with an SSB index of 1) through a reflector, and then performs initial beam alignment on the 1st SSB beam, then the base station will instruct the terminal to measure for refinement information of the 1st SSB beam and / or measure the 2nd SSB beam adjacent to the 1st SSB beam.

[0204] At this time, if the terminal moves to the 3rd SSB beam area, the terminal may move out of the coverage of the reflector, and may not be able to find another beam to switch to during the beam switching phase, and may have to perform the operation of finding all beams again because alternative beam information cannot be found during the beam failure recovery phase.

[0205] On the other hand, if the terminal had aligned with the 4th SSB beam instead of the 1st SSB beam received through the reflector, then when the terminal moved to the 3rd SSB beam area, it could have switched to the adjacent beam (i.e., the 3rd SSB beam) during the beam switching phase. Therefore, efficient beam management could have been performed.

[0206] Figure 18 shows an example of operation between a base station and a terminal.

[0207] Referring to FIG. 18, the base station can broadcast SSB 1, 2, 3, and 4 at a period of, for example, 5ms (S181). The terminal can receive, for example, SSB 1 and SSB 3, where SSB 3 is a signal received directly from the base station, and let us assume that SSB 1 is a signal received through a reflector.

[0208] The terminal cannot determine whether the multiple received SSBs were received directly from the base station or through a reflector.

[0209] The terminal transmits RACH to the base station to synchronize uplink and downlink time (UL&DL time synchronization) with the base station (S182).

[0210] At this time, for example, i) a beam can be selected based on the highest SSB RSRP and RACH can be transmitted in that direction, or ii) the SSB with the smallest delay time can be selected through the time domain correlation of all received SSBs and RACH can be transmitted.

[0211] For example, if SSB 1 is selected based on RSRP, Preamble 1 can be transmitted via RACH during the random access (RA) opportunity associated with SSB 1, and if SSB 3 is selected, Preamble 2 can be transmitted via RACH during the random access opportunity associated with SSB 3.

[0212] At this time, from the perspective of the base station, it is not possible to distinguish whether the preamble received through RACH is received directly from the terminal or received through a reflector.

[0213] When the base station receives a RACH, it can identify an SSB associated with the RACH, check whether a reflector is included in the area / direction of the SSB, and include the result as an additional parameter in the Random Access Response (RAR) and transmit it to the terminal (S183).

[0214] For example, a random access response may include a reflector indicator. A value of 0 for the reflector indicator may indicate that the area contains a reflector, and 1 for that area does not contain a reflector (of course, conversely to the above example, a value of 0 for the reflector indicator may indicate that the area does not contain a reflector, and 1 for that area contains a reflector).

[0215] For example, if the base station identifies an SSB as SSB 1 and knows that there is a reflector in the area / direction of SSB 1, it can notify the terminal that there is a reflector via RAR.

[0216] The terminal checks through the received RAR whether there is a reflector in the area / direction of the SSB beam associated / related to the RACH it transmitted, and checks whether there is an additional SSB measured within the same cell.

[0217] If none exist, the terminal can expect that there is only the SSB received from the reflector in the shadow area, so it does not perform any additional actions.

[0218] If there is an additionally measured SSB and the received SNR is above a certain level capable of receiving the PBCH, the terminal performs an additional operation.

[0219] For example, the terminal can select an SSB that meets specific conditions. The terminal can select an SSB that meets the specific conditions based on the CP boundary currently aligned with DL synchronization. Alternatively, the terminal may select all measured SSBs.

[0220] If the terminal measures an SSB index that satisfies a specific condition, it includes the index value in MSG3 (message 3) and transmits it to the base station.

[0221] MSG3 may include, for example, at least one of a cell ID, cause information, and SSB index information.

[0222] When the base station receives the above MSG3, it can determine that there is an SSB that the terminal can receive directly from the base station via LoS, and also determine the index of the said SSB.

[0223] If the base station knows that there is an SSB index that allows it and the terminal to align in the LoS direction, it can artificially perform beam switching to the LoS direction beam instead of the SSB beam in the direction containing the reflector.

[0224] When performing beam switching, since the end-to-end distances between SSB beams are different, the base station can compensate for the uplink through the difference in delay distance between the two SSB beams in the following way.

[0225] The terminal signals by additionally including the serving beam reference DL time difference within the MSG3 (S184). In this case, the MSG3 may include at least one of a cell ID, cause information, SSB index information, and time difference information.

[0226] The base station may request the terminal to transmit an additional RACH to synchronize the UL with the SSB beam received directly from the base station. In this case, when the serving beam is interrupted due to blockage while the terminal is transmitting UL data, the base station may receive a feedback message from the beam that is aligned with the UL synchronization of another SSB beam.

[0227] The base station transmits to the terminal, including information in MSG4 that enables additional measurement of adjacent SSB indices containing the corresponding SSB index (S185).

[0228] Since CSI-RS measurements can be mapped port-by-port in the frequency domain, the base station may need to know in advance whether the terminal can measure CSI-RS simultaneously. Depending on the terminal's capability, the base station can transmit accurate measurement information to the terminal via additional messages.

[0229] The base station can determine that the terminal can simultaneously serve the SSB beam in the direction / area where a reflector exists and the SSB beam received directly from the base station. Therefore, by closely measuring the two SSB beams, it is possible to quickly respond to beam switching based on the terminal's mobility.

[0230] According to the method of the present disclosure, when a terminal is present in an area where the coverage of a reflector and the coverage of a base station overlap, efficient beam management can be performed by enabling the base station to know the beam that forms a LoS between the base station and the terminal.

[0231] FIG. 19 illustrates a method of operation of a terminal according to one embodiment of the present disclosure.

[0232] Referring to FIG. 19, the terminal receives SSB position information from the base station that indicates time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted within a half frame (S191).

[0233] For example, the above SSB location information may be provided in the form of a bitmap. In this case, each bit of the bitmap may correspond to an SSB index, such as the first (leftmost) bit of the bitmap corresponding to SSB index 0 and the second bit corresponding to SSB index 1. In the bitmap, a value of 0 may indicate that the corresponding SSB is not transmitted, and a value of 1 may indicate that the corresponding SSB is transmitted. The SSB indices provided by the SSB location information may be mapped to valid PRACH (physical random access channel) opportunities.

[0234] The terminal receives a plurality of SSBs at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH) (S192). The SSBs have been described above with reference to FIG. 14.

[0235] The terminal selects a first SSB among the plurality of SSBs (S193).

[0236] For example, as the first SSB, the SSB with the highest Reference Signal Received Power (RSRP) among the plurality of SSBs can be selected.

[0237] Alternatively, for example, as the first SSB, the SSB with the smallest delay time among the plurality of SSBs may be selected based on time domain correlation.

[0238] The terminal transmits a random access signal to the base station (network) in the direction of the beam of the first SSB (S194). For example, the terminal can transmit the random access signal through a random access resource associated with the first SSB. The random access signal can be transmitted through a random access channel (RACH).

[0239] The terminal receives a random access response in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB (S195).

[0240] When the reflector information indicates that there is a reflector in the area, the terminal measures a second SSB that satisfies a specific condition for beam management (S196). For example, if the reflector information has a first value (e.g., 0), it indicates that there is a reflector in the area, and if it has a second value (e.g., 1), it indicates that there is no reflector in the area. The specific condition may be that the signal-to-noise ratio (SNR) of the second SSB is greater than a specific value that allows the PBCH to be received.

[0241] The beam direction of the second SSB above may be a beam direction in which a line of sight (LoS) is formed between the terminal and the base station.

[0242] The terminal transmits the information of the second SSB to the base station (S197).

[0243] Although not illustrated in FIG. 19, according to an embodiment, the terminal may further receive a message from the base station instructing a measurement for SSBs having a beam index within a specific value from the beam index of the second SSB (i.e., an index adjacent to the beam index of the second SSB).

[0244] Meanwhile, if the above reflector information indicates that there is no reflector in the area, the terminal may skip the measurement of the second SSB.

[0245] According to the method of the present disclosure, beam management of a base station can be performed efficiently in a wireless communication system where a reflector is present. As a result, communication efficiency between the base station and the terminal can be increased, thereby increasing the throughput of the system and improving the reliability of communication.

[0246] FIG. 20 illustrates a wireless device that can be applied to the present specification.

[0247] Referring to FIG. 20, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR).

[0248] The first wireless device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this document. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may store software code containing instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In this specification, a wireless device may refer to a communication modem / circuit / chip.

[0249] At least one processor (102) receives SSB position information indicating time domain positions of a synchronization signal and a physical broadcast channel block (SSB) transmitted within a half frame from a base station, and receives a plurality of SSBs at the time domain positions, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH), selects a first SSB among the plurality of SSBs, transmits a random access signal in the beam direction of the first SSB, and receives a random access response in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and if the reflector information indicates that there is a reflector in the area, measures a second SSB that satisfies a specific condition for beam management, and transmits information of the second SSB to the base station.

[0250] The second wireless device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). Memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document. Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with an RF unit. In this specification, a wireless device may mean a communication modem / circuit / chip.

[0251] At least one processor (202) transmits SSB position information that informs the terminal of time domain positions of a synchronization signal and a physical broadcast channel block (SSB) transmitted within a half frame, and transmits a plurality of SSBs to the terminal at the time domain positions, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH), receives a random access signal transmitted by the terminal in the beam direction of a first SSB selected by the terminal among the plurality of SSBs, and transmits a random access response to the terminal in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and receives a measurement result of a second SSB satisfying a specific condition for beam management from the terminal based on the reflector information indicating that there is a reflector in the area, and in communication with the terminal It is characterized by performing beam switching to use the beam direction of the second SSB.

[0252] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate a signal (e.g., baseband signal) containing a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document.

[0253] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). One or more processors (102, 202) may also be implemented as at least one computer-readable medium (CRM) containing instructions based on being executed by at least one processor.

[0254] For example, each method described in FIGS. 14 to 19 may be performed by at least one computer-readable medium (CRM) comprising an instruction based on execution by at least one processor. The above CRM includes instructions executed by at least one processor to cause the at least one processor to perform operations, wherein the operations include receiving SSB position information indicating time domain positions of a Synchronization Signal and physical broadcast channel block (SSB) transmitted from a base station within a half frame, and receiving a plurality of SSBs at the time domain positions, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH), selecting a first SSB among the plurality of SSBs, transmitting a random access signal in the beam direction of the first SSB, and receiving a random access response in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and if the reflector information indicates that there is a reflector in the area, satisfying a specific condition for beam management It includes measuring the second SSB and transmitting the information of the second SSB to the base station.

[0255] The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0256] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0257] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in this document from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document through one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0258] FIG. 21 illustrates an example of a signal processing module structure. Here, signal processing may be performed in the processor (102, 202) of FIG. 20.

[0259] Referring to FIG. 21, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (301), a modulator (302), a layer mapper (303), an antenna port mapper (304), a resource block mapper (305), and a signal generator (306).

[0260] The transmission device can transmit one or more codewords. Each coded bit within a codeword is scrambled by a scrambler (301) and transmitted over a physical channel. A codeword may be referred to as a data sequence and may be equivalent to a transmission block, which is a data block provided by the MAC layer.

[0261] The scrambled bits are modulated into complex-valued modulation symbols by a modulator (302). The modulator (302) can modulate the scrambled bits according to a modulation scheme to arrange them into complex-valued modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and m-PSK (m-Phase Shift Keying) or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data. The modulator may be referred to as a modulation mapper.

[0262] The complex modulation symbols above can be mapped to one or more transmission layers by a layer mapper (303). The complex modulation symbols on each layer can be mapped by an antenna port mapper (304) for transmission on an antenna port.

[0263] The resource block mapper (305) can map complex modulation symbols for each antenna port to appropriate resource elements within a virtual resource block allocated for transmission. The resource block mapper can map the virtual resource block to a physical resource block according to an appropriate mapping scheme. The resource block mapper (305) can assign complex modulation symbols for each antenna port to appropriate subcarriers and multiplex them according to the user.

[0264] The signal generator (306) can generate a complex-valued time domain OFDM symbol signal by modulating a complex modulation symbol for each antenna port, for example, an antenna-specific symbol, using a specific modulation method, for example, OFDM (Orthogonal Frequency Division Multiplexing). The signal generator can perform an Inverse Fast Fourier Transform (IFFT) on the antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0265] FIG. 22 illustrates another example of a signal processing module structure within a transmission device. Here, signal processing can be performed in a processor of a terminal / base station, such as the processor (102, 202) of FIG. 20.

[0266] Referring to FIG. 22, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (401), a modulator (402), a layer mapper (403), a precoder (404), a resource block mapper (405), and a signal generator (406).

[0267] For one codeword, the transmission device can scramble the coded bits within the codeword by the scrambler (401) and then transmit them through the physical channel.

[0268] The scrambled bits are modulated into complex modulation symbols by a modulator (402). The modulator may modulate the scrambled bits according to a predetermined modulation scheme to arrange them into complex modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying), or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data.

[0269] The complex modulation symbol can be mapped to one or more transmission layers by the layer mapper (403).

[0270] Complex modulation symbols on each layer can be precoded by a precoder (404) for transmission on an antenna port. Here, the precoder may perform precoding after performing transform precoding on the complex modulation symbols. Alternatively, the precoder may perform precoding without performing transform precoding. The precoder (404) may process the complex modulation symbols in a MIMO manner according to multiple transmission antennas to output antenna-specific symbols and distribute the antenna-specific symbols to the corresponding resource block mapper (405). The output z of the precoder (404) can be obtained by multiplying the output y of the layer mapper (403) by an N-X-M precoding matrix W. Here, N is the number of antenna ports and M is the number of layers.

[0271] The resource block mapper (405) maps the demodulation modulation symbol for each antenna port to the appropriate resource element within the virtual resource block allocated for transmission.

[0272] The resource block mapper (405) can assign complex modulation symbols to appropriate subcarriers and multiplex them according to the user.

[0273] The signal generator (406) can generate a complex-valued time domain Orthogonal Frequency Division Multiplexing (OFDM) symbol signal by modulating a complex modulated symbol using a specific modulation method, such as OFDM. The signal generator (406) can perform an Inverse Fast Fourier Transform (IFFT) on an antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator (406) may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0274] The signal processing process of the receiving device can be configured as the inverse of the signal processing process of the transmitter. Specifically, the processor of the receiving device performs decoding and demodulation for a wireless signal received from the outside through the antenna port(s) of the transmitter and receiver. The receiving device may include multiple receiving antennas, and each signal received through the receiving antennas is restored to a baseband signal, then undergoes multiplexing and MIMO demodulation to be restored to the data sequence that the transmitting device originally intended to transmit. The receiving device (1820) may include a signal restorer for restoring the received signal to a baseband signal, a multiplexer for combining and multiplexing the received processed signals, and a channel demodulator for demodulating the multiplexed signal sequence into the corresponding codeword. The signal restorer, multiplexer, and channel demodulator may be configured as a single integrated module or as separate independent modules that perform their functions. More specifically, the signal restorer may include an analog-to-digital converter (ADC) that converts an analog signal into a digital signal, a CP remover that removes CP from the digital signal, an FFT module that applies a fast Fourier transform (FFT) to the signal from which CP has been removed to output a frequency domain symbol, and a resource element demapper / equalizer that restores the frequency domain symbol to an antenna-specific symbol. The antenna-specific symbol is restored to a transport layer by a multiplexer, and the transport layer is restored to a codeword that the transmitting device intended to transmit by a channel demodulator.

[0275] FIG. 23 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0276] Referring to FIG. 23, a wireless communication device, for example, a terminal, may include at least one of a processor (2310), such as a digital signal processor (DSP) or a microprocessor, a transceiver (2335), a power management module (2305), an antenna (2340), a battery (2355), a display (2315), a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), a memory (2330), a Subscriber Identification Module (SIM) card (2325), a speaker (2345), and a microphone (2350). The antenna and the processor may be multiple.

[0277] The processor (2310) can implement the functions, procedures, and methods described in this specification. The processor (2310) of FIG. 23 may be the processor (102, 202) of FIG. 20.

[0278] The memory (2330) is connected to the processor (2310) and stores information related to the operation of the processor. The memory may be located inside or outside the processor and may be connected to the processor through various technologies such as wired or wireless connections. The memory (2330) of FIG. 23 may be the memory (104, 204) of FIG. 20.

[0279] The user can input various types of information, such as phone numbers, using various techniques, such as pressing a button on the keypad (2320) or using a microphone (2350) to activate sound. The processor (2310) receives and processes the user's information and can perform appropriate functions, such as making a call to the input phone number. In some scenarios, data may be retrieved from a SIM card (2325) or memory (2330) to perform appropriate functions. In some scenarios, the processor (2310) can display various types of information and data on a display (2315) for the user's convenience.

[0280] A transceiver (2335) is connected to a processor (2310) to transmit and / or receive a wireless signal, such as a Radio Frequency (RF) signal. The processor may control the transceiver to initiate communication or to transmit a wireless signal containing various types of information or data, such as voice communication data. The transceiver includes a transmitter and a receiver for transmitting and receiving wireless signals. An antenna (2340) may facilitate the transmission and reception of wireless signals. In some embodiments, when the transceiver receives a wireless signal, it may forward and convert the signal to a baseband frequency for processing by the processor. The processed signal may be processed by various techniques, such as being converted into audible or readable information to be output through a speaker (2345). The transceiver of FIG. 23 may be the transceiver (106, 206) of FIG. 20.

[0281] Although not illustrated in FIG. 23, various components such as a camera and a USB (Universal Serial Bus) port may be additionally included in the terminal. For example, the camera may be connected to the processor (2310).

[0282] FIG. 23 is merely one example of an implementation of a terminal, and is not limited thereto. The terminal is not required to include all the elements of FIG. 23. For example, some components, such as a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), and a SIM card (2325), may not be essential and, in this case, may not be included in the terminal.

[0283] Figure 24 illustrates another example of a wireless device.

[0284] According to FIG. 24, the wireless device may include at least one processor (102, 202), at least one memory (104, 204), at least one transceiver (106, 206), and one or more antennas (108, 208).

[0285] The difference between the example of the wireless device described in FIG. 20 and the example of the wireless device in FIG. 24 is that in FIG. 20, the processor (102, 202) and the memory (104, 204) are separated, whereas in the example of FIG. 24, the memory (104, 204) is included in the processor (102, 202). For example, the processor and the memory may form a single chipset.

[0286] FIG. 25 illustrates a communication system (1) applicable to the present specification.

[0287] Referring to FIG. 25, the communication system (1) to which the present specification applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with wireless communication capabilities, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of HMDs (Head-Mounted Devices), HUDs (Head-Up Displays) equipped in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0288] Wireless devices (100a to 100f) can be connected to a network (300) through a base station (200). Artificial Intelligence (AI) technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices (100a to 100f) may communicate with each other through the base station (200) / network (300), but they may also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0289] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base station (200) and base station (200) / base station (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of this specification, at least some of the following may be performed: various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0290] Meanwhile, NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands; when the SCS is 30 kHz / 60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth; and when the SCS is 60 kHz or higher, it supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0291] The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values ​​of the frequency ranges may change; for example, the frequency ranges of the two types (FR1, FR2) may be as shown in Table 5 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean the “sub 6GHz range” and FR2 may mean the “above 6GHz range” and may be referred to as millimeter wave (mmW).

[0292] [Table 5]

[0293]

[0294] As described above, the numerical values ​​of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 6 below. For example, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0295] [Table 6]

[0296]

[0297] The claims described in this specification may be combined in various ways. For example, the technical features of the method claims in this specification may be combined to be implemented as a device, and the technical features of the device claims in this specification may be combined to be implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a device, and the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a method.

Claims

1. The method is, A terminal receives SSB location information indicating time domain positions of a synchronization signal and a physical broadcast channel block (SSB) transmitted from a base station within a half frame, and The terminal receives a plurality of SSBs at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH (physical broadcast channel), and Among the plurality of SSBs mentioned above, the terminal selects the first SSB, and The terminal transmits a random access signal in the direction of the beam of the first SSB, and The terminal receives a random access response in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB. When the above reflector information indicates that there is a reflector in the above area, the terminal measures a second SSB that satisfies specific conditions for beam management, and A method characterized by the terminal transmitting the information of the second SSB above to the base station.

2. A method according to claim 1, characterized in that the first SSB selected is the SSB with the highest Reference Signal Received Power (RSRP) among the plurality of SSBs.

3. A method according to claim 1, characterized in that the SSB with the smallest delay time among the plurality of SSBs is selected as the first SSB based on time domain correlation.

4. A method according to claim 1, characterized in that the random access signal is transmitted through a random access channel (RACH).

5. A method according to claim 1, wherein the specific condition is that the received signal-to-noise ratio (SNR) of the second SSB is greater than a specific value for receiving the PBCH.

6. A method according to claim 1, wherein the beam direction of the second SSB is a beam direction in which a line of sight (LoS) is formed between the terminal and the base station.

7. A method according to claim 1, characterized in that the terminal further receives a message from the base station instructing a measurement for SSBs having a beam index having a value within a specific value from the beam index of the second SSB.

8. A method according to claim 1, characterized in that when the reflector information indicates that there is no reflector in the area, the measurement of the second SSB is skipped.

9. A method according to claim 1, characterized in that if the reflector information has a first value, it indicates that there is a reflector in the area, and if it has a second value, it indicates that there is no reflector in the area.

10. The terminal, At least one transceiver; At least one memory; and at least one processor operating in combination with the above-mentioned at least one transceiver and the above-mentioned at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are Receive SSB position information indicating time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted from the base station within a half frame, and Receive a plurality of SSBs at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH (physical broadcast channel), and Select a first SSB from among the above plurality of SSBs, and Transmit a random access signal in the beam direction of the first SSB, and A random access response is received in response to the above random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and If the above reflector information indicates that there is a reflector in the above area, a second SSB satisfying specific conditions for beam management is measured, and A terminal characterized by transmitting information of the above-mentioned second SSB to the above-mentioned base station.

11. A terminal according to claim 10, characterized in that, among the plurality of SSBs, the SSB with the highest Reference Signal Received Power (RSRP) is selected as the first SSB.

12. A terminal according to claim 10, characterized in that the first SSB selected from among the plurality of SSBs is the SSB with the smallest delay time based on time domain correlation.

13. A terminal according to claim 10, characterized in that the random access signal is transmitted through a random access channel (RACH).

14. A terminal according to claim 10, wherein the specific condition is that the received signal-to-noise ratio (SNR) of the second SSB is greater than a specific value for receiving the PBCH.

15. A terminal according to claim 10, wherein the beam direction of the second SSB is a beam direction in which a line of sight (LoS) is formed between the terminal and the base station.

16. A terminal according to claim 10, characterized in that the terminal further receives a message from the base station instructing a measurement for SSBs having a beam index having a value within a specific value from the beam index of the second SSB.

17. A terminal according to claim 10, characterized in that when the reflector information indicates that there is no reflector in the area, the measurement of the second SSB is skipped.

18. A terminal according to claim 10, characterized in that if the reflector information has a first value, it indicates that there is a reflector in the area, and if it has a second value, it indicates that there is no reflector in the area.

19. At least one computer-readable medium comprising instructions that are executed by at least one processor and cause said at least one processor to perform operations, The above operations are Receive SSB position information indicating time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted from the base station within a half frame, and Receive a plurality of SSBs at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH (physical broadcast channel), and Select a first SSB from among the above plurality of SSBs, and Transmit a random access signal in the beam direction of the first SSB, and A random access response is received in response to the above random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and If the above reflector information indicates that there is a reflector in the above area, a second SSB satisfying specific conditions for beam management is measured, and A medium characterized by including the transmission of information of the second SSB to the base station.

20. A chipset is, At least one memory; and At least one processor that operates in combination with the above at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are Receive SSB position information indicating time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted from the base station within a half frame, and Receive a plurality of SSBs at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH (physical broadcast channel), and Select a first SSB from among the above plurality of SSBs, and Transmit a random access signal in the beam direction of the first SSB, and A random access response is received in response to the above random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB, and If the above reflector information indicates that there is a reflector in the above area, a second SSB satisfying specific conditions for beam management is measured, and A chipset characterized by including the transmission of information of the second SSB to the base station.

21. The method is, The base station transmits SSB location information that informs the terminal of the time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted within a half frame, and The base station transmits a plurality of SSBs to the terminal at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a physical broadcast channel (PBCH), and The base station receives a random access signal transmitted by the terminal in the beam direction of the first SSB selected by the terminal among the plurality of SSBs above, and The base station transmits a random access response to the terminal in response to the above random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB. Based on the fact that the above reflector information indicates that there is a reflector in the above area, the base station receives a measurement result of a second SSB satisfying specific conditions for beam management from the terminal, and A method characterized in that the base station performs beam switching to use the beam direction of the second SSB for communication with the terminal.

22. A base station is, At least one transceiver; At least one memory; and at least one processor operating in combination with the above-mentioned at least one transceiver and the above-mentioned at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are, Transmit SSB position information that informs the terminal of the time domain positions of the synchronization signal and physical broadcast channel block (SSB) transmitted within a half frame, and Transmitting a plurality of SSBs to the terminal at the above time domain locations, wherein each of the plurality of SSBs includes i) a primary synchronization signal and a secondary synchronization signal and ii) a PBCH (physical broadcast channel), Receiving a random access signal transmitted by the terminal in the beam direction of the first SSB selected by the terminal among the plurality of SSBs above, and A random access response is transmitted to the terminal in response to the random access signal, wherein the random access response includes reflector information indicating whether there is a reflector in the area associated with the first SSB. Based on the fact that the above reflector information indicates that there is a reflector in the above area, the measurement result of the second SSB satisfying specific conditions for beam management is received from the terminal, and A base station characterized by performing beam switching to use the beam direction of the second SSB for communication with the terminal.

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