Method and apparatus for recovering beam failure in a wireless communication system

Abstract

A method and apparatus for performing beam failure recovery in a wireless communication system are disclosed. In a method of a terminal transmitting an uplink or receiving a downlink according to an embodiment of the disclosure, the method includes the steps of: transmitting a beam failure recovery request (BFRQ) to a base station based on detecting a beam failure in at least one resource group among a plurality of resource groups; receiving a response to the BFRQ from the base station; and transmitting information related to the beam failure to the base station, wherein the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a wireless communication system, and more particularly, to a beam failure recovery method and apparatus in a wireless communication system. BACKGROUND

[0002] A mobile communication system has been developed to provide a voice service while guaranteeing the mobility of a user. However, the mobile communication system has been expanded to a data service as well as a voice service, and currently, an explosive increase in traffic has led to a shortage of resources, and users have required faster services, and thus a more advanced mobile communication system has been required.

[0003] The overall requirements of the next-generation mobile communication system should be able to support the accommodation of explosive data traffic, a significant increase in transmission rate per user, the accommodation of a significantly increased number of connected devices, a very low end-to-end latency, and high energy efficiency. To this end, various technologies such as dual connectivity, massive multiple input multiple output (massive MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), ultra-wideband support, device networking, etc. have been researched. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] The technical object of the disclosure is to provide a method and apparatus for performing beam failure recovery in a wireless communication system.

[0006] In addition, an additional technical object of the disclosure is to provide a method and apparatus for performing beam failure recovery when beam failure occurs in a specific resource group or a plurality of resource groups.

[0007] The technical objects realized by the disclosure are not limited to the above-mentioned technical objects, and other technical objects not described herein will be clearly understood by a person skilled in the art from the following description.

[0008] TECHNICAL SOLUTION

[0009] In an embodiment of the disclosure, a method for a UE to perform beam failure recovery (BFR) in a wireless communication system can include transmitting a beam failure recovery request (BFRQ) to a base station based on detecting beam failure in at least one resource group among a plurality of resource groups, receiving a response to the BFRQ from the base station, and transmitting information related to the beam failure to the base station, and the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or the plurality of resource groups in which the beam failure is detected.

[0010] As another embodiment of the disclosure, a method for a base station to perform a beam failure recovery (BFR) in a wireless communication system can include receiving a beam failure recovery request (BFRQ) from a user equipment (UE) based on detecting a beam failure in at least one resource group among a plurality of resource groups, transmitting a response for the BFRQ to the UE, and receiving information related to the beam failure from the UE, and the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or the plurality of resource groups in which the beam failure is detected.

[0011] Advantageous Effects

[0012] According to embodiments of the disclosure, a method and apparatus for performing a beam failure recovery can be provided in a wireless communication system.

[0013] According to embodiments of the disclosure, when a beam failure occurs in a specific resource group or a plurality of resource groups, a method and apparatus for performing a beam failure recovery operation can be provided.

[0014] Effects the disclosure can achieve are not limited to what has been described hereinabove and other effects that have not been described will become apparent to those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings, which are included as part of the detailed description of the disclosure and serve to understand the detailed description of the disclosure, provide embodiments of the disclosure and describe technical features of the disclosure through the detailed description.

[0016] Figure 1 FIG. 1 illustrates a structure of a wireless communication system to which the disclosure can be applied.

[0017] Figure 2 FIG. 2 illustrates a frame structure in a wireless communication system to which the disclosure can be applied.

[0018] Figure 3 FIG. 3 illustrates a resource grid in a wireless communication system to which the disclosure can be applied.

[0019] Figure 4 FIG. 4 illustrates a physical resource block in a wireless communication system to which the disclosure can be applied.

[0020] Figure 5 FIG. 5 illustrates a slot structure in a wireless communication system to which the disclosure can be applied.

[0021] Figure 6 FIG. 6 illustrates physical channels used in a wireless communication system to which the disclosure can be applied and a general signal transmission and reception method using the physical channels.

[0022] Figure 7FIG. 1 illustrates a method of multiple TRP transmission in a wireless communication system to which the disclosure is applied.

[0023] Figure 8 FIG. 2 is a diagram for describing a beam failure recovery operation of a terminal according to an embodiment of the disclosure.

[0024] Figure 9 FIG. 3 is a diagram for describing a beam failure recovery operation of a base station according to an embodiment of the disclosure.

[0025] Figure 10 FIG. 4 is a diagram for describing a signaling procedure of a network side and a terminal according to the disclosure.

[0026] Figure 11 FIG. 5 illustrates a block diagram of a wireless communication system according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed in the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to represent the only embodiment in which the disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the disclosure. However, those skilled in the relevant art will know that the disclosure can be implemented without the specific details.

[0028] In some cases, known structures and devices can be omitted or can be shown in the form of a block diagram based on each core function in order to facilitate the prevention of obscuring the concept of the disclosure.

[0029] In the disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it can include an indirect connection relationship between the other element and a further element in addition to a direct connection relationship. In addition, in the disclosure, the term "include" or "have" designates the existence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0030] In the disclosure, terms such as "first", "second", and the like are used only to distinguish one element from another element, and do not limit the order or importance of the elements, unless otherwise specified, and do not limit the order or importance of the elements. Therefore, within the scope of the disclosure, a first element in an embodiment can be referred to as a second element in another embodiment, and likewise, a second element in an embodiment can be referred to as a first element in another embodiment.

[0031] The terms used in the present disclosure are to describe specific embodiments, not to limit the claims. As used in the description of embodiments and the appended claims, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and / or" used in the present disclosure can refer to one of the relevant listed items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, " / " between words in the present disclosure has the same meaning as "and / or".

[0032] The present disclosure describes a wireless communication network or a wireless communication system, and operations performed in a wireless communication network can be performed in a process in which a device (e.g., a base station) controlling a network and transmitting or receiving a signal controls the corresponding wireless communication network, or can be performed in a process in which a terminal associated with the corresponding wireless network transmits or receives a signal between the network or the terminal.

[0033] In the present disclosure, a transmission or reception channel includes the meaning of transmitting or receiving information or a signal through a corresponding channel. For example, transmitting a control channel means transmitting control information or a control signal through a control channel. Similarly, transmitting a data channel means transmitting data information or a data signal through a data channel.

[0034] Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, a transmitter can be a part of a base station, and a receiver can be a part of a terminal. In the uplink, a transmitter can be a part of a terminal, and a receiver can be a part of a base station. The base station can be expressed as a first communication device, and the terminal can be expressed as a second communication device. The base station (BS) can be replaced with terms such as a fixed station, a Node B, an eNB (evolved Node B), a gNB (next-generation Node B), a BTS (base transceiver system), an access point (AP), a network (5G network), an AI (artificial intelligence) system / module, an RSU (roadside unit), a robot, a drone (UAV: unmanned aerial vehicle), an AR (augmented reality) device, a VR (virtual reality) device, etc. In addition, the terminal can be fixed as well as mobile, and can be replaced with terms such as a UE (user equipment), a MS (mobile station), a UT (user terminal), a MSS (mobile subscriber station), a SS (subscriber station), an AMS (advanced mobile station), a WT (wireless terminal), an MTC (machine type communication) device, an M2M (machine to machine) device, a D2D (device to device) device, a vehicle, an RSU (roadside unit), a robot, an AI (artificial intelligence) module, a drone (UAV: unmanned aerial vehicle), an AR (augmented reality) device, a VR (virtual reality) device, etc.

[0035] The following description can be used for various radio access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and the like. CDMA can be implemented by such a radio technology as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented by such a radio technology as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented by such a radio technology as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (Evolved UTRA), and the like. UTRA is a part of UMTS (Universal Mobile Telecommunications System). 3GPP (Third Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) using E-UTRA and LTE-A (Advanced) / LTE-A pro is a high-speed version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is a high-speed version of 3GPP LTE / LTE-A / LTE-A pro.

[0036] For the sake of clearer description, based on a 3GPP communication system (e.g., LTE-A, NR), but the technical idea of the disclosure is not limited thereto. LTE means a technology after Release 8 of 3GPP TS (Technical Specification) 36.xxx. Specifically, LTE technology in or after Release 10 of 3GPP TS 36.xxx or after Release 13 of 3GPP TS 36.xxx is referred to as LTE-A, and LTE technology in or after Release 13 of 3GPP TS 36.xxx is referred to as LTE-A pro. 3GPP NR means a technology in or after Release 15 of TS 38.xxx. LTE / NR can be referred to as a 3GPP system. "xxx" means a detailed number of a standard document. LTE / NR can be generally referred to as a 3GPP system. For the background art, terms, abbreviations, etc. used to describe the disclosure, matters described in standard documents disclosed before the disclosure can be referred to. For example, the following documents can be referred to.

[0037] For 3GPP LTE, TS 36.211 (Physical Channels and Modulation), TS 36.212 (Multiplexing and Channel Coding), TS 36.213 (Physical Layer Procedures), TS 36.300 (Overall Description), TS 36.331 (Radio Resource Control) can be referred to.

[0038] For 3GPP NR, reference can be made to TS 38.211 (Physical channels and modulation), TS 38.212 (Multiplexing and channel coding), TS 38.213 (Physical layer procedures for control), TS 38.214 (Physical layer procedures for data), TS 38.300 (NR and NG-RAN (New Generation-Radio Access Network) overall description), TS 38.331 (Radio Resource Control protocol specification).

[0039] Abbreviations of terms that can be used in this disclosure are defined as follows.

[0040] -BM: Beam Management

[0041] -CQI: Channel Quality Indicator

[0042] -CRI: Channel State Information-Reference Signal Resource Indicator

[0043] -CSI: Channel State Information

[0044] -CSI-IM: Channel State Information-Interference Measurement

[0045] -CSI-RS: Channel State Information-Reference Signal

[0046] -DMRS: Demodulation Reference Signal

[0047] -FDM: Frequency Division Multiplexing

[0048] -FFT: Fast Fourier Transform

[0049] -IFDMA: Interleaved Frequency Division Multiple Access

[0050] -IFFT: Inverse Fast Fourier Transform

[0051] -L1-RSRP: Layer 1 Reference Signal Received Power

[0052] -L1-RSRQ: Layer 1 Reference Signal Received Quality

[0053] -MAC: Medium Access Control

[0054] -NZP: Non-Zero Power

[0055] -OFDM: Orthogonal Frequency Division Multiplexing

[0056] -PDCCH: Physical Downlink Control Channel

[0057] -PDSCH: Physical Downlink Shared Channel

[0058] -PMI: Precoding Matrix Indicator

[0059] -RE: Resource Element

[0060] - RI: Rank Indicator

[0061] - RRC: Radio Resource Control

[0062] - RSSI: Received Signal Strength Indicator

[0063] - Rx: Reception

[0064] - QCL: Quasi Co-Location

[0065] - SINR: Signal to Interference Noise Ratio

[0066] - SSB (or SS / PBCH block): Synchronization Signal Block (including PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel))

[0067] - TDM: Time Division Multiplexing

[0068] - TRP: Transmission and Reception Point

[0069] - TRS: Tracking Reference Signal

[0070] - Tx: Transmission

[0071] - UE: User Equipment

[0072] - ZP: Zero Power

[0073] Overall system

[0074] As more communication devices require higher capacity, there has been a demand for improved mobile broadband communication compared to existing radio access technologies (RATs). In addition, massive MTC (Machine Type Communication) that provides various services anytime anywhere by connecting multiple devices and things is also one of the main issues to be considered in the next-generation communication. In addition, communication system design considering services / terminals sensitive to reliability and latency is also discussed. Therefore, the introduction of the next-generation RAT considering eMBB (enhanced mobile broadband communication), mMTC (massive MTC), URLLC (ultra-reliable and low-latency communication), etc. is discussed, and for convenience, the corresponding technology is referred to as NR in the present disclosure. NR is an expression indicating an example of a 5G RAT.

[0075] A new RAT system including the NR uses an OFDM transmission method or a transmission method similar thereto. The new RAT system can follow OFDM parameters different from those of the LTE. Alternatively, the new RAT system follows the parameters of the existing LTE / LTE-A as they are, but can support a wider system bandwidth (for example, 100 MHz). Alternatively, one cell can support multiple numerologies. In other words, terminals operating according to different numerologies can coexist in one cell.

[0076] A numerology corresponds to one subcarrier spacing in a frequency domain. Different numerologies can be defined as the reference subcarrier spacing is scaled by an integer N.

[0077] Figure 1 The structure of a wireless communication system to which the disclosure can be applied is illustrated.

[0078] Reference Figure 1 , the NG-RAN is configured with gNBs providing control plane (RRC) protocol endpoints for NG-RA (NG Radio Access) user plane (i.e., new AS (Access Stratum) sublayer / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC / PHY) and UE. The gNBs are interconnected with each other over an Xn interface. Further, the gNBs are connected to a NGC (Next Generation Core) through an NG interface. More specifically, the gNBs are connected to an AMF (Access and Mobility Management Function) through an N2 interface and to a UPF (User Plane Function) through an N3 interface.

[0079] Figure 2 The frame structure in a wireless communication system to which the disclosure can be applied is illustrated.

[0080] The NR system can support multiple numerologies. Here, a numerology can be defined by a subcarrier spacing and a cyclic prefix (CP) overhead. Here, multiple subcarrier spacings can be derived by scaling a basic (reference) subcarrier spacing by an integer N (or, μ). Further, although it is assumed that a very low subcarrier spacing is not used in a very high carrier frequency, a numerology to be used can be selected independently of a frequency band. Further, various frame structures according to multiple numerologies can be supported in the NR system.

[0081] Hereinafter, OFDM numerologies and frame structures that can be considered in the NR system will be described. Multiple OFDM numerologies supported in the NR system can be defined as in Table 1 below.

[0082] [Table 1]

[0083] μ Δf = 2 μ · 15 [kHz] ] > CP 0 15 Normal 1 30 Normal 2 60 Normal, extended 3 120 Normal 4 240 Normal

[0084] NR supports multiple parameter sets (or subcarrier spacing (SCS)) to support various 5G services. For example, a 15kHz SCS supports wide-area coverage of traditional cellular bands; a 30kHz / 60kHz SCS supports dense urban areas, lower latency, and wider carrier bandwidth; and a 60kHz or higher SCS supports bandwidths exceeding 24.25GHz to overcome phase noise. NR bands are defined as frequency ranges of two types (FR1, FR2). FR1 and FR2 can be configured as shown in Table 2 below. Additionally, FR2 can refer to millimeter wave (mmW).

[0085] [Table 2]

[0086] Frequency range designation Corresponding frequency range Subcarrier spacing FR1 410 MHz - 7125 MHz 15, 30, 60 kHz FR2 24250 MHz - 52600 MHz 60, 120, 240 kHz

[0087] Regarding the frame structure in the NR system, the size of various fields in the time domain is expressed as T. c =1 / (Δf) max ·N f A multiple of the time unit. Here, Δf max i is 480·10 3 Hz, and N f The value is 4096. Downlink and uplink transmissions are configured (organized) to have a duration T. f＝ 1 / (Δf max N f / 100)·T c A radio frame of 10ms. Here, the radio frame is configured with 10 subframes, each with a T... sf =(Δf max N f / 1000)·T c The duration. In this case, there may be one set of frames for the uplink and one set of frames for the downlink. Furthermore, the transmission in the i-th uplink frame from the terminal should begin T earlier than the corresponding downlink frame in the corresponding terminal. TA =(N TA +N TA,offset )T c Begin. For the subcarrier spacing configuration μ, the time slots are arranged in n-order within the subframe. s μ ∈{0,...,N slot subframe,μ The numbers are numbered in ascending order from -1, and in the radio frames, they are numbered in n... s,f μ ∈{0,...,N slot frame,μ The time slot is configured with N in ascending order of -1. symb slotone continuous OFDM symbol, and N symb slot is determined according to the CP. The start of the slot n s μ in the same subframe as the OFDM symbol n s μ N symb slot are arranged in time. All terminals can not perform transmission and reception at the same time, which means that all OFDM symbols of a downlink slot or an uplink slot can not be used. Table 3 represents the number of OFDM symbols (N symb slot ) per slot, the number of slots (N slot frame,μ ) per radio frame, and the number of slots (N slot subframe,μ ) per subframe in normal CP, and Table 4 represents the number of OFDM symbols per slot, the number of slots per radio frame, and the number of slots per subframe in extended CP.

[0088] [Table 3]

[0089] μ N symb slot ]]> N slot frame,μ ]]> N slot subframe,μ ]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

[0090] [Table 4]

[0091] μ N symb slot ]]> N slot frame,μ ]]> N slot subframe,μ ]]> 2 12 40 4

[0092] Figure 2 is an example of μ = 2 (SCS is 60 kHz), referring to Table 3, 1 subframe can include 4 slots. As shown in 1 subframe = {1, 2, 4} in Figure 2 is an example, the number of slots that can be included in 1 subframe is defined as in Table 3 or Table 4. In addition, a mini-slot can include 2, 4, or 7 symbols or more or less symbols. With respect to physical resources in an NR system, an antenna port, a resource grid, a resource element, a resource block, a carrier part, etc. can be considered.

[0093] Hereinafter, physical resources that can be considered in an NR system will be described in detail. First, with respect to an antenna port, an antenna port is defined such that a channel carrying a symbol in the antenna port can be inferred from a channel carrying other symbols in the same antenna port. When a large-scale property of a channel in which a symbol in one antenna port is carried can be inferred from a channel in which a symbol of another antenna port is carried, it can be said that 2 antenna ports are in a QC / QCL (Quasi Co-Location or Quasi Co-located) relationship. In this case, the large-scale property includes at least one of a delay spread, a Doppler spread, a frequency shift, an average received power, a received timing.

[0094] Figure 3The illustration shows a resource grid in a wireless communication system to which this disclosure can be applied. (Reference) Figure 3 The diagram illustrates the resource grid configuration with N in the frequency domain. RB μ N sc RB There are 14.2 subcarriers, and one subframe is configured with 14.2 μ The number of OFDM symbols is not limited to this. In an NR system, the transmitted signal consists of 2 OFDM symbols. μ N symb (μ) Each OFDM symbol and configuration has N RB μ N sc RB It is described by one or more resource grids of N subcarriers. Here, N RB μ ≤N RB max,μ N RB max,μ This represents the maximum transmission bandwidth, which may differ between uplink and downlink, and between parameter sets. In this case, each μ and antenna port p can be configured with a resource grid. Each element of the resource grid used for μ and antenna port p is called a resource element and is uniquely identified by an index pair (k, l'). Here, k = 0, ..., N RB μ N sc RB -1 is the index in the frequency domain, and l' = 0, ..., 2 μ N symb (μ) -1 indicates the symbol position within the subframe. When referencing resource elements in a time slot, the index pair (k, l) is used. Here, l = 0,...,N symb μ -1. The resource element (k,l') used for μ and antenna port p corresponds to the complex value a. k,l' (p,μ) When there is no risk of confusion or when a specific antenna port or parameter set is not specified, the indices p and μ may be discarded, and the complex value may be a. k,l' (p) or a k,l' Furthermore, a resource block (RB) is defined as N in the frequency domain. sc RB = 12 consecutive subcarriers.

[0095] Point A serves as a common reference point for the resource block grid and is obtained as follows.

[0096] - offsetToPointA for primary cell (PCell) downlink indicates a frequency offset between point A and the lowest subcarrier of the lowest resource block overlapping with the SS / PBCH block used by the terminal for initial cell selection. It is expressed in units of resource blocks assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

[0097] - absoluteFrequencyPointA indicates a frequency location of point A expressed in ARFCN (absolute radio frequency channel number).

[0098] For subcarrier spacing configuration μ, common resource blocks are numbered from 0 upwards in the frequency domain. The center of subcarrier 0 of common resource block 0 for subcarrier spacing configuration μ is the same as in "point A". The common resource block number n for subcarrier spacing configuration μ in the frequency domain is given by CRB μ The relationship between resource element (k, l) and

[0099] [Equation 1]

[0100]

[0101] In Equation 1, k is defined with respect to point A such that k = 0 corresponds to the subcarrier centered at point A. Physical resource blocks are numbered from 0 to N BWP,i size,μ - 1 and i is the number of the BWP. Physical resource block n PRB in BWP i is given by CRB The relationship between resource element (k, l) and

[0102] [Equation 2]

[0103]

[0104] N BWP,i start,μ is the common resource block where the BWP starts with respect to common resource block 0.

[0105] Figure 4 A wireless communication system in which the present disclosure can be applied is illustrated. Also, Figure 5 A slot structure in a wireless communication system in which the present disclosure can be applied is illustrated.

[0106] Referring to Figure 4 and Figure 5 , a slot includes a plurality of symbols in the time domain. For example, 1 slot includes 7 symbols for a normal CP, but 1 slot includes 6 symbols for an extended CP.

[0107] A carrier includes multiple subcarriers in a frequency domain. A RB (Resource Block) is defined as multiple (e.g., 12) consecutive subcarriers in a frequency domain. A BWP (Bandwidth Part) is defined as multiple consecutive (physical) resource blocks in a frequency domain and can correspond to one numerology (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed through an activated BWP, and only one BWP can be activated for one terminal. In a resource grid, each element is referred to as a resource element (RE) and one complex symbol can be mapped.

[0108] In an NR system, each component carrier (CC) can support up to 400 MHz. If a terminal operating in such a wideband CC always operates to turn on a radio frequency (RF) chip for the entire CC, terminal battery consumption can increase. Alternatively, when considering multiple application cases operating in one wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.), different numerologies (e.g., subcarrier spacing, etc.) can be supported in each frequency band in the corresponding CC. Alternatively, each terminal can have different capabilities for the maximum bandwidth. In consideration of this, a base station can instruct a terminal to operate only in part of the bandwidth, rather than in the full bandwidth of the wideband CC, and for convenience, the corresponding part of the bandwidth is defined as a bandwidth part (BWP). A BWP can be configured with consecutive RBs on a frequency axis and can correspond to one numerology (e.g., subcarrier spacing, CP length, slot / min-slot duration).

[0109] Meanwhile, even in one CC configured to a terminal, the base station can configure multiple BWPs. For example, a BWP occupying a relatively small frequency domain can be configured in a PDCCH monitoring slot, and a PDSCH indicated by a PDCCH can be scheduled in a larger BWP. Alternatively, when UEs are congested in a specific BWP, some terminals can be configured with other BWPs for load balancing. Alternatively, considering frequency domain inter-cell interference cancellation between neighboring cells, etc., some middle frequency spectrum of the full bandwidth can be excluded, and BWPs on both edges can be configured in the same slot. In other words, the base station can configure at least one DL / UL BWP to a terminal associated with a wideband CC. The base station can activate at least one of the configured DL / UL BWPs at a specific time (through L1 signaling or MAC CE (Control Element) or RRC signaling, etc.). In addition, the base station can indicate switching to other configured DL / UL BWPs (through L1 signaling or MAC CE or RRC signaling, etc.). Alternatively, based on a timer, when the timer value expires, switching to a determined DL / UL BWP can be made. Here, the activated DL / UL BWP is defined as an active DL / UL BWP. However, before the terminal performs an initial access procedure or sets up an RRC connection, a configuration on the DL / UL BWP can not be received, so the DL / UL BWP assumed by the terminal in these cases is defined as an initial active DL / UL BWP.

[0110] Figure 6 A physical channel used in a wireless communication system to which the disclosure is applicable and a general signal transmission and reception method using the same are illustrated.

[0111] In a wireless communication system, a terminal receives information from a base station through a downlink and transmits information to the base station through an uplink. The information transmitted and received by the base station and the terminal includes data and various control information, and there are various physical channels according to the type / use of the information they transmit and receive.

[0112] When a terminal is turned on or newly enters a cell, it performs an initial cell search including synchronization with a base station, etc. (S601). For the initial cell search, the terminal can synchronize with the base station by receiving a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station and acquire information such as a cell identifier (ID), etc. Then, the terminal can acquire broadcast information in the cell by receiving a physical broadcast channel (PBCH) from the base station. Meanwhile, the terminal can check a downlink channel state by receiving a downlink reference signal (DL RS) in the initial cell search stage.

[0113] The terminal that completes the initial cell search can acquire more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried in the PDCCH (S602).

[0114] Meanwhile, when the terminal first accesses to the base station or does not have a radio resource for signal transmission, it can perform a random access (RACH) procedure to the base station (S603 to S606). For the random access procedure, the terminal can transmit a specific sequence as a preamble through a physical random access channel (PRACH) (S603 and S605), and can receive a response message to the preamble through the PDCCH and the corresponding PDSCH (S604 and S606). The contention-based RACH can additionally perform a contention resolution procedure.

[0115] The terminal that performs the above-described procedure later can perform PDCCH / PDSCH reception (S607) and PUSCH (physical uplink shared channel) / PUCCH (physical uplink control channel) transmission (S608) as a general uplink / downlink signal transmission procedure. Specifically, the terminal receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and the format varies according to its use purpose.

[0116] Meanwhile, control information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station includes a downlink / uplink ACK / NACK (acknowledgement / non-acknowledgement) signal, a CQI (channel quality indicator), a PMI (precoding matrix indicator), an RI (rank indicator), etc. For the 3GPP LTE system, the terminal can transmit the control information of the CQI / PMI / RI, etc. described above through the PUSCH and / or the PUCCH.

[0117] Table 5 represents an example of a DCI format in the NR system.

[0118] [Table 5]

[0119]

[0120] Referring to Table 5, the DCI formats 0_0, 0_1, and 0_2 can include resource information (e.g., UL / SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), information related to a transport block (TB) (e.g., MCS (Modulation Coding and Scheme), NDI (New Data Indicator), RV (Redundancy Version), etc.), information related to HARQ (Hybrid-Automatic Repeat and Request) (e.g., process number, DAI (Downlink Assignment Index), PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), power control information related to scheduling of PUSCH (e.g., PUSCH power control, etc.), and control information included in each DCI format can be predefined. The DCI format 0_0 is used to schedule PUSCH in one cell. Information included in the DCI format 0_0 is CRC (Cyclic Redundancy Check) scrambled by C-RNTI (Cell Radio Network Temporary Identifier) or CS-RNTI (Configured Scheduling RNTI) or MCS-C-RNTI (Modulation Coding Scheme Cell RNTI) and is transmitted.

[0121] The DCI format 0_1 is used to indicate scheduling of one or more PUSCHs or to configure grant (CG) downlink feedback information to a terminal in one cell. Information included in the DCI format 0_1 is scrambled by C-RNTI or CS-RNTI or SP-CSI-RNTI (Semi-Persistent CSI RNTI) or MCS-C-RNTI and is transmitted.

[0122] The DCI format 0_2 is used to schedule PUSCH in one cell. Information included in the DCI format 0_2 is scrambled by C-RNTI or CS-RNTI or SP-CSI-RNTI or MCS-C-RNTI and is transmitted.

[0123] Next, the DCI formats 1_0, 1_1, and 1_2 can include resource information (e.g., frequency resource allocation, time resource allocation, VRB (Virtual Resource Block)-PRB (Physical Resource Block) mapping, etc.), information related to a transport block (TB) (e.g., MCS, NDI, RV, etc.), information related to HARQ (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., antenna port, TCI (Transmission Configuration Indicator), SRS (Sounding Reference Signal) request, etc.), information related to PUCCH with respect to scheduling of PDSCH (e.g., PUCCH power control, PUCCH resource indicator, etc.), and control information included in each DCI format can be predefined.

[0124] The DCI format 1_0 is used for scheduling of PDSCH in one DL cell. The information included in the DCI format 1_0 is CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI and transmitted.

[0125] The DCI format 1_1 is used for scheduling of PDSCH in one cell. The information included in the DCI format 1_1 is CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI and transmitted.

[0126] The DCI format 1_2 is used for scheduling of PDSCH in one cell. The information included in the DCI format 1_2 is CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI and transmitted.

[0127] Operations related to multiple TRPs

[0128] A coordinated multipoint (CoMP) scheme refers to a scheme in which multiple base stations exchange or utilize channel information (e.g., RI / CQI / PMI / LI (layer indicator), etc.) fed back by a terminal (e.g., using an X2 interface) and cooperatively transmit to the terminal to effectively control interference. According to the scheme used, CoMP can be classified into joint transmission (JT), coordinated scheduling (CS), coordinated beamforming (CB), dynamic point selection (DPS), dynamic point blanking (DPB), etc.

[0129] An M-TRP transmission scheme in which M TRPs transmit data to one terminal can be mainly classified into i) eMBB M-TRP transmission, a scheme for improving a transmission rate, and ii) URLLC M-TRP transmission, a scheme for increasing a reception success rate and reducing latency.

[0130] In addition, with respect to DCI transmission, the M-TRP transmission scheme can be classified into i) M-DCI (multiple DCI) based M-TRP transmission in which different DCIs are transmitted per TRP, and ii) S-DCI (single DCI) based M-TRP transmission in which one TRP transmits a DCI. For example, for S-DCI based M-TRP transmission, all scheduling information about data transmitted by M TRPs should be delivered to a terminal through one DCI, which can be used in an environment of ideal backhaul (ideal BH) in which dynamic cooperation between two TRPs is possible.

[0131] For TDM-based URLLC M-TRP transmission, Scheme 3 / 4 is being discussed for standardization. Specifically, Scheme 4 refers to a scheme in which one TRP transmits a transport block (TB) in one slot, and it has the effect of improving the probability of data reception by receiving the same TB from multiple TRPs in multiple slots. Meanwhile, Scheme 3 refers to a scheme in which one TRP transmits a TB through a consecutive number of OFDM symbols (i.e., a symbol group), and the TRP can be configured to transmit the same TB through different symbol groups in one slot.

[0132] In addition, the UE can recognize PUSCH (or PUCCH) scheduled by DCI received in different control resource sets (CORESETs) (or CORESETs belonging to different CORESET groups) as PUSCH (or PUCCH) transmitted to different TRPs, or can recognize PDSCH (or PDCCH) from different TRPs. In addition, the method described below for UL transmission (e.g., PUSCH / PUCCH) transmitted to different TRPs can be equally applied to UL transmission (e.g., PUSCH / PUCCH) transmitted to different panels belonging to the same TRP.

[0133] Hereinafter, a multi-DCI-based non-coherent joint transmission (NCJT) / single-DCI-based NCJT will be described.

[0134] NCJT (non-coherent joint transmission) is a scheme in which multiple transmission points (TPs) transmit data to one terminal by using the same time-frequency resource, and the TPs transmit data using different DMRSs (demodulation reference signals) between the TPs through different layers (i.e., through different DMRS ports).

[0135] The TPs deliver data scheduling information to a terminal receiving NCJT through DCI. Here, a scheme in which each TP participating in NCJT delivers scheduling information about data transmitted by itself through DCI is referred to as "multi-DCI-based NCJT". Since each of the N TPs participating in NCJT transmission transmits a DL grant DCI and a PDSCH to the UE, the UE receives N DCIs and N PDSCHs from the N TPs. Meanwhile, a scheme in which one representative TP delivers scheduling information about data transmitted by itself and data transmitted by different TPs (i.e., TPs participating in NCJT) through one DCI is referred to as "single-DCI-based NCJT". Here, the N TPs transmit one PDSCH, but each TP transmits only some of the multiple layers included in one PDSCH. For example, when 4 layers of data are transmitted, TP 1 can transmit 2 layers to the UE, and TP 2 can transmit 2 remaining layers to the UE.

[0136] By using any one of the following two schemes, multiple TRPs (MTRP) performing NCJT transmission can transmit DL data to a terminal.

[0137] First, a "single-DCI-based MTRP scheme" is described. MTRPs cooperatively transmit one common PDSCH, and each TRP participating in cooperative transmission divides and transmits the corresponding PDSCH into different layers (i.e., different DMRS ports) in space by using the same time-frequency resource. Here, scheduling information about the PDSCH is indicated to the UE through one DCI, and which DMRS (group) port uses which QCL RS and QCL type information is indicated by the corresponding DCI (which is different from the DCI indicating the QCL RS and type to be commonly applied to all DMRS ports as indicated in the existing scheme). In other words, M TCI states (e.g., M=2 for 2-TRP cooperative transmission) can be indicated through the TCI (Transmission Configuration Indicator) field in the DCI, and QCL RS and type can be indicated by using M different TCI states for M DMRS port groups. In addition, DMRS port information can be indicated by using a new DMRS table.

[0138] Next, a "multiple-DCI-based MTRP scheme" is described. Each MTRP transmits a different DCI and PDSCH, and the corresponding PDSCH (part or all) overlaps each other and is transmitted in a frequency-time resource. The corresponding PDSCH can be scrambled by different scrambling IDs (identifiers), and the DCI can be transmitted by CORESETs belonging to different CORESET groups. (Here, the CORESET group can be identified by an index defined in the CORESET configuration of each CORESET. For example, when index = 0 is configured for CORESET 1 and 2 and index = 1 is configured for CORESET 3 and 4, CORESET 1 and 2 are CORESET group 0, and CORESET 3 and 4 belong to CORESET group 1. Furthermore, when the index is not defined in the CORESET, it can be interpreted as index = 0.) When multiple scrambling IDs are configured in one serving cell or two or more CORESET groups are configured, the UE can note that it receives data according to the multiple-DCI-based MTRP operation.

[0139] Alternatively, it can be indicated to the UE through separate signaling whether it is a single-DCI based MTRP scheme or a multiple-DCI based MTRP scheme. In an example, for one serving cell, multiple CRS (Cell Reference Signal) patterns for MTRP operation can be indicated to the UE. In this case, depending on the single-DCI based MTRP scheme or the multiple-DCI based MTRP scheme, the PDSCH rate matching for the CRS can be different (as the CRS patterns are different).

[0140] Hereinafter, the CORESET group ID described / referred to in the disclosure can refer to index / identification information (e.g., ID, etc.) for CORESETs distinguished per TRP / panel. In addition, the CORESET group can be a group / union of CORESETs distinguished by index / identification information (e.g., ID) / CORESET group ID, etc. for CORESETs distinguished per TRP / panel. In an example, the CORESET group ID can be specific index information defined in the CORESET configuration. In this case, the CORESET group can be configured / indicated / defined by the index defined in the CORESET configuration for each CORESET. Additionally / alternatively, the CORESET group ID can refer to index / identification information / indicator, etc. for distinguishing / identifying between CORESETs configured / associated with each TRP / panel. Hereinafter, the CORESET group ID described / referred to in the disclosure can be expressed by replacing with a specific index / a specific identification information / a specific indicator for distinguishing / identifying between CORESETs configured / associated with each TRP / panel. The CORESET group ID, i.e., the specific index / the specific identification information / the specific indicator for distinguishing / identifying between CORESETs configured / associated with each TRP / panel, can be configured / indicated to the terminal through higher layer signaling (e.g., RRC signaling) / L2 signaling (e.g., MAC-CE) / L1 signaling (e.g., DCI), etc. In an example, it can be configured / indicated so that PDCCH detection is performed per TRP / panel in units of the corresponding CORESET group, i.e., per TRP / panel belonging to the same CORESET group. Additionally / alternatively, it can be configured / indicated so that uplink control information (e.g., CSI, HARQ-A / N (ACK / NACK), SR (scheduling request)) and / or uplink physical channel resources (e.g., PUCCH / PRACH / SRS resources) are separated and managed / controlled per TRP / panel in units of the corresponding CORESET group, i.e., per TRP / panel belonging to the same CORESET group. Additionally / alternatively, HARQ A / N (processing / retransmission) for PDSCH / PUSCH, etc. scheduled per TRP / panel can be managed per the corresponding CORESET group, i.e., per TRP / panel belonging to the same CORESET group.

[0141] Hereinafter, a method for improving reliability in multi-TRP will be described.

[0142] In addition, the NCJT can be classified into a full overlap NCJT in which time-frequency resources transmitted by each TP are fully overlapped and a partial overlap NCJT in which only some time-frequency resources are overlapped. In other words, for the partial overlap NCJT, data of both TP 1 and TP 2 is transmitted in some time-frequency resources, and data of only one of TP 1 or TP 2 is transmitted in the remaining time-frequency resources.

[0143] Hereinafter, a method for improving reliability in a multi-TRP will be described.

[0144] The following two methods can be considered as transmission / reception methods for improving reliability using transmission in a multi-TRP.

[0145] Figure 7 A method of multi-TRP transmission in a wireless communication system to which the disclosure can be applied is illustrated.

[0146] Reference Figure 7 (a) shows a case in which layer groups transmitting the same codeword (CW) / transport block (TB) correspond to different TRPs. Here, the layer group can refer to a predetermined layer set including one or more layers. In this case, there is an advantage that the amount of transmission resources increases due to the number of layers, so that a robust channel coding with a low coding rate can be used for the TB, and additionally, because the multiple TRPs have different channels, it can be expected to improve the reliability of the received signal based on a diversity gain.

[0147] Reference Figure 7 (b) shows an example of transmitting different CWs through layer groups corresponding to different TRPs. Here, it can be assumed that TBs corresponding to CW#1 and CW#2 in the figure are the same as each other. In other words, CW#1 and CW#2 refer to the same TB being transformed into different CWs by different TRPs through channel coding, etc., respectively. Thus, it can be seen as an example of repeatedly transmitting the same TB. In Figure 7 (b), compared to Figure 7 (a), has a disadvantage that the coding rate corresponding to the TB is higher. However, it has an advantage that the coding rate can be adjusted by indicating different RV (redundancy version) values, or the modulation order of each CW generated from the coded bits of the same TB can be adjusted according to the channel environment.

[0148] According to the above Figure 7 (a) and Figure 7(b) The method shown can improve the data reception probability of the UE, because the same TB is repeatedly sent by different layer groups, and each layer group is sent by different TRP / panel. This is called an M-TRP URLLC transmission method based on spatial division multiplexing (SDM). The layers belonging to different layer groups are respectively sent by DMRS ports belonging to different DMRS CDM groups.

[0149] In addition, the above-mentioned content related to multiple TRPs is described based on the SDM (spatial division multiplexing) method using different layers, but it can be naturally extended and applied to the FDM (frequency division multiplexing) method based on different frequency domain resources (for example, RB / PRB (set), etc.) and / or the TDM (time division multiplexing) method based on different time domain resources (for example, time slots, symbols, sub-symbols, etc.).

[0150] Regarding the method for multiple TRP-based URLLC scheduled by a single DCI, the following methods are discussed.

[0151] 1) Method 1 (SDM): Time and frequency resource allocation is overlapped, and n (n<=Ns) TCI states in a single slot

[0152] 1-a) Method 1a

[0153] - The same TB is sent in one layer or layer set at each transmission time (occasion), and each layer or each layer set is associated with one TCI and one DMRS port set.

[0154] - A single code word with one RV is used in all spatial layers or all layer sets. Regarding the UE, different coded bits are mapped to different layers or layer sets by using the same mapping rule.

[0155] 1-b) Method 1b

[0156] - The same TB is sent in one layer or layer set at each transmission time (occasion), and each layer or each layer set is associated with one TCI and one DMRS port set.

[0157] - A single code word with one RV is used in each spatial layer or each layer set. The RV(s) corresponding to each spatial layer or each layer set can be the same or different.

[0158] 1-c) Method 1c

[0159] - The same TB with one DMRS port associated with multiple TCI state indexes is sent in one layer at one transmission time (occasion), or the same TB with multiple DMRS ports one-to-one associated with multiple TCI state indexes is sent in one layer.

[0160] In case of the above methods 1a and 1c, the same MCS is applied to all layers or all layer sets.

[0161] 2) Method 2 (FDM): Frequency resource allocations are not overlapped and n (n<=Nf) TCI states in a single slot

[0162] - Each non-overlapping frequency resource allocation is associated with one TCI state.

[0163] - The same single / multiple DMRS port is associated with all non-overlapping frequency resource allocations.

[0164] 2-a) Method 2a

[0165] - A single codeword with one RV is used for all resource allocations. With respect to the UE, a common RB matching (codeword-to-layer mapping) is applied to all resource allocations.

[0166] 2-b) Method 2b

[0167] - A single codeword with one RV is used for each non-overlapping frequency resource allocation. The RVs corresponding to each non-overlapping frequency resource allocation can be the same or different.

[0168] For the above method 2a, the same MCS is applied to all non-overlapping frequency resource allocations.

[0169] 3) Method 3 (TDM): Time resource allocations are not overlapped and n (n<=Nt1) TCI states in a single slot

[0170] - Each transmission time (occasion) of the TB has a time granularity of a mini-slot and has one TCI and one RV.

[0171] - A common MCS is used with single or multiple DMRS ports at all transmission times (occasions) in a slot.

[0172] - The RV / TCI can be the same or different at different transmission times (occasions).

[0173] 4) Method 4 (TDM): n (n<=Nt2) TCI states in K (n<=K) different slots

[0174] - Each transmission time (occasion) of the TB has one TCI and one RV.

[0175] - A common MCS is used with single or multiple DMRS ports across all transmission times (occasions) of the K slots.

[0176] - RV / TCI can be the same or different at different transmission times (occasions).

[0177] Basic beam failure recovery

[0178] The UE and / or the base station can perform uplink / downlink beam management (BM) for data transmission / reception. Here, the BM can refer to a procedure of obtaining and maintaining a set of beams that can be used for downlink and uplink transmission / reception.

[0179] Specifically, the BM can include a beam measurement procedure of measuring characteristics of a beamformed signal received from a base station or a UE, a beam determination procedure of determining a transmission beam (Tx beam) and a reception beam (Rx beam) of the base station or the terminal itself, a beam sweeping procedure of covering a spatial region using a transmission beam and / or a reception beam in a predetermined time interval in a predetermined manner, and a beam reporting procedure of a UE reporting information of a beam signal to a base station based on a beam measurement result.

[0180] When the above-described uplink / downlink BM procedure is performed, a beam mismatch problem can occur due to various factors. For example, when the UE moves or rotates, or when a radio channel environment changes due to the movement of a nearby object (for example, when it is a line of sight (LoS) environment and then changes to a non-LoS environment as the beam is blocked), the best uplink / downlink beam pair can change. At this time, when the UE or the base station fails to track the changed best uplink / downlink beam pair (i.e., BM tracking), it can be considered that a beam failure has occurred.

[0181] The UE can determine whether a beam failure has occurred based on the reception quality of a downlink reference signal (RS). In addition, the UE must report a report message to the base station about whether a beam failure has occurred or a message for a beam recovery request (beam failure recovery request message, BFRQ message). Upon receiving this message, the base station can perform a beam recovery procedure through various procedures such as a beam RS transmission or a beam reporting request for beam recovery. This series of beam recovery procedures is referred to as a beam failure recovery (BFR) procedure.

[0182] The basic BFR operation includes a BFR procedure for a special cell (SpCell) (i.e., a primary cell PCell) or a primary secondary cell (PScell) for which a contention-based PRACH resource exists. The BFR procedure can be composed of a beam failure detection (BFD) procedure of the UE, a BFRQ transmission procedure, and a procedure of monitoring the response of the base station to the BFRQ, and each procedure can be performed in a serving cell.

[0183] Beam failure detection (BFD)

[0184] When the quality value of all PDCCH beams (Q_out) is lower than a predefined value, it can be considered that a beam failure instance has occurred. Here, the quality value can be determined based on a hypothetical block error rate (BLER). That is, the theoretical BLER can represent the probability of demodulation failure of control information when transmitting the control information on a specific PDCCH.

[0185] In addition, one or more search spaces for monitoring PDCCH can be configured in the UE, and the PDCCH beams can be differently configured for each search space. In this case, when the quality value of all PDCCH beams is lower than a predefined value, it means that the quality value of all PDCCH beams is lower than a BLER threshold.

[0186] Two methods that will be described later can be supported as a method for the UE to receive an indication / configuration of a BFD-RS from the base station to determine whether a beam failure instance has occurred.

[0187] As a first method, an implicit configuration method of a BFD-RS can be supported. A control resource set (CORESET) ID that is a resource area in which PDCCH can be transmitted is configured in each search space, and RS information (e.g., CSI-RS resource ID, SSB ID) that is QCLed in terms of spatial RX parameters can be indicated / configured for each CORESET ID. The RS that is QCLed can be indicated or configured by transmission configuration information (TCI) in consideration of the spatial reception parameters. That is, the BFD-RS can be implicitly configured / indicated to the UE based on the QCL information indicated or configured by the TCI.

[0188] Here, when the base station indicates or configures the RS that is QCLed in terms of spatial reception parameters (i.e., QCL Type D RS) to the UE, when the UE receives a specific PDCCH DMRS, a beam for receiving the RS that is QCLed in terms of spatial reception parameters can be used. That is, signals can be transmitted between antenna ports that are spatially QCLed by the same transmission beam or a similar transmission beam (e.g., when the beam width is different but the beam direction is the same / similar).

[0189] As a second method, an explicit configuration method of a BFD-RS can be supported. The base station can explicitly configure or indicate the UE to use a beam RS for BFD. In this case, the beam RS can correspond to "all PDCCH beams".

[0190] Whenever an event occurs that the theoretical BLER degradation based on the configured (or indicated) BFD-RS measurement exceeds a certain threshold, the UE physical layer can inform the MAC sublayer that a BFI (Beam Failure Instance) has occurred. In addition, the UE MAC sublayer can determine that a beam failure has occurred and initiate the related RACH operation when the BFI occurs a predetermined number of times (e.g., “beamFailureInstanceMaxCount”) within a predetermined time (e.g., “BFD timer”).

[0191] In the following, the operation of the MAC layer related to BFD will be described.

[0192] The MAC entity can:

[0193] 1> if a beam failure instance indication is received from lower layers:

[0194] 2> start or restart the beamFailureDetectionTimer

[0195] 2> increment BFI_COUNTER by 1

[0196] 2> if BFI_COUNTER >= beamFailureInstanceMaxCount:

[0197] initiate a random access procedure on SpCell

[0198] 1> if the beamFailureDetectionTimer expires; or

[0199] 1> if the beamFailureDetectionTimer, beamFailureInstanceMaxCount or any reference signal used for beam failure detection is reconfigured by upper layers

[0200] 2> set BFI_COUNTER to 0

[0201] 1> if the random access procedure is successfully completed:

[0202] 2> set BFI_COUNTER to 0

[0203] 2> stop the (configured) beamFailureRecoveryTimer

[0204] 2> consider that the beam failure recovery procedure has been successfully completed

[0205] BFRQ (PRACH-based): new beam identification and PRACH transmission

[0206] As described above, when more than a certain number of BFIs are generated, the UE can determine that a beam failure has occurred, and can perform a beam failure recovery operation. As an example of the beam failure recovery operation, the UE can perform a BFRQ procedure based on RACH (i.e., PRACH). Hereinafter, the corresponding BFRQ procedure will be described in detail.

[0207] When a beam failure occurs, the base station can configure a terminal with a candidate beam RS list including alternative candidate beam RSs through RRC signaling ("candidateBeamRSList"). Also, the base station can configure a dedicated PRACH resource for the candidate beam RS. In this case, the dedicated PRACH resource can be a non-contention-based PRACH resource (or contention-free PRACH resource). When an alternative beam RS is not found in the candidate beam RS list, the UE can select at least one of the pre-configured SSB resources. Also, the UE can transmit a contention-based PRACH to the base station based on the selected at least one. The detailed procedure for transmitting the contention-based PRACH is as follows.

[0208] The UE can determine a beam RS having a quality value Q_in equal to or greater than a predefined value among a plurality of beam RSs included in the candidate beam RS list configured by the base station (step 1). Here, the quality value of the beam RS can be determined based on a reference signal received power (RSRP).

[0209] In addition, the candidate beam RS list configured by the base station to the UE can be all configured by SSB, all configured by CSI-RS resources, or configured by a combination of SSB and CSI-RS resources.

[0210] If the quality value of one beam RS among the plurality of beam RSs included in the candidate beam RS list exceeds the threshold value (i.e., the predefined value), the UE can select the beam RS. Also, when the quality values of a plurality of beam RSs in the candidate beam RS list exceed the threshold value, the UE can select any one of the plurality of beam RSs.

[0211] If there is no beam RS whose quality value exceeds the threshold value among the plurality of beam RSs included in the candidate beam RS list, the UE can perform an operation according to step 2 described later.

[0212] The UE can determine a beam RS having a quality value (Q_in) greater than or equal to a predefined value among SSBs (connected to contention-based PRACH resources) (step 2).

[0213] If the quality value of one of the SSBs exceeds the threshold value, the UE can select the SSB. Also, when the quality values of a plurality of SSBs among the SSBs exceed the threshold value, the UE can select any one of the plurality of SSBs.

[0214] If there is no SSB whose quality value exceeds the threshold value among the SSBs, the UE can perform an operation according to Step 3 which will be described later.

[0215] The UE can select any SSB from among the SSBs (connected to the contention-based PRACH resource) (Step 3).

[0216] In addition, the UE can transmit, to the base station, a PRACH resource and a preamble configured to be directly or indirectly connected to the beam RS (CSI-RS or SSB) selected in the above-described step (Step 1 or Step 2).

[0217] For example, when the contention-free PRACH resource and the preamble are configured for the beam RS in the candidate beam RS list for BFR, or when the contention-based PRACH resource and the preamble are configured in a generally configured SSB such as random access, the UE can transmit the PRACH resource and the preamble configured to be directly connected to the selected beam RS to the base station.

[0218] As another example, when the contention-free PRACH resource and the preamble are not configured for the CSI-RS in the candidate beam RS list for BFR, the UE can transmit the PRACH resource and the preamble configured to be indirectly connected to the selected beam RS to the base station. Specifically, the UE can select and transmit, to the base station, the contention-free PRACH resource and the preamble associated with the SSB indicated as being capable of being received with a reception beam corresponding to the corresponding CSI-RS (i.e., QCLed for spatial reception parameters).

[0219] Monitoring the gNB response to the BFRQ

[0220] The UE can monitor the response of the base station to the PRACH and preamble transmission.

[0221] If the UE transmits the contention-free PRACH resource and the preamble to the base station, the base station can transmit a response to the UE through a PDCCH masked with a C-RNTI. The UE receives the response in a search space configured for BFR use (via RRC signaling). In this case, the search space is configured in a specific CORESET for BFR use.

[0222] And, when the UE transmits a contention-based PRACH and preamble to the base station, the base station can transmit a response to the UE by reusing a CORESET (e.g., CORESET 0 or CORESET 1) and a search space configured for a random access procedure on the basis of the contention-based PRACH.

[0223] If there is no response from the base station for a certain period of time (i.e., if the response of the base station is not monitored for a certain period of time), the UE performs a new candidate beam identification and selection procedure, and repeats the procedure of monitoring the BFRQ and the response of the base station.

[0224] The above-described new candidate beam identification and selection procedure can be performed until the PRACH transmission is performed a maximum number of times N_max configured in advance, or until a configured timer (BFR timer) expires. When the timer expires, the UE can stop the contention-free PRACH transmission or perform the contention-based PRACH transmission through SSB selection until N_max is reached.

[0225] Enhanced beam failure recovery

[0226] When carrier aggregation (CA) is applied, there can be no uplink (UL) carrier in a certain SCell. That is, in the case where the SCell has only a downlink carrier, uplink transmission is not possible. And, even if there is an uplink carrier in the SCell, a contention-based PRACH cannot be configured. Therefore, a PRACH-based BFR procedure applied to CA can be applied only to an SpCell (PCell or PSCell) in a limited manner, and the BFR procedure can not be supported for an SCell. That is, according to the basic BFR operation, a PRACH-based BFR operation in the SpCell can not be supported in the SCell.

[0227] Specifically, when a high frequency band requiring BFR is configured to an SCell, a PRACH-based BFR procedure can not be supported in the corresponding high frequency band. For example, when a PCell operates in a low frequency band (e.g., 6 GHz or less) and an SCell operates in a high frequency band (e.g., 30 GHz), there is a problem that a PRACH-based BFR procedure is not supported in the high frequency band requiring more BFR support.

[0228] To solve the above-described problem, an improved BFR operation includes an operation for BFR of an SCell. For example, a UE can perform a BFRQ for an SCell by using a dedicated PUCCH resource for the BFRQ configured in an SpCell. Hereinafter, for convenience of description, the "dedicated PUCCH resource" will be referred to as a BFR-PUCCH.

[0229] The role of the BFR-PRACH introduced in the basic BFR is to report "beam failure (BF) occurrence information and new candidate beam RS (set) information" to the base station together. On the other hand, the role of the BFR-PUCCH is to report only "BF occurrence information for SCell" to the base station. In addition, detailed information related to the generated BF can be transmitted to the base station as a subsequent report through the BFR MAC-CE or UCI.

[0230] Here, the detailed information transmitted as a subsequent report can include information on the SCell(s) in which BF occurs (for example, CC (component carrier) index information), whether there is a new candidate beam for the SCell(s) in which BF occurs, and the corresponding beam RS ID when there is a new candidate beam.

[0231] In addition, the BFR-PUCCH can use the same PUCCH format as the SR (scheduling request), and can be defined by the ID of a specific SR for BFR use. If there is an UL-SCH allocated from the base station when the UE detects BF for the SCell, the UE can omit the BFR-PUCCH transmission procedure like the SR transmission procedure, and directly transmit the BFR MAC-CE to the base station through the allocated UL-SCH.

[0232] Method for performing TRP-specific BFR in MTRP environment

[0233] When performing a PRACH-based BFR operation in a multiple-DCI-based NCJT environment among MTRP environments, if BF occurs in all CORESETs belonging to a specific TRP, but there is a CORESET in which BF does not occur among the CORESETs belonging to the other TRP, the UE can determine that the current situation is not a BF situation.

[0234] At this time, if the TRP in which BF occurs in all CORESETs is a TRP (for example, a primary TRP) responsible for transmitting important control information (for example, SIB, RA, paging information, etc.), even if beam failure does not occur in a specific beam of another TRP (for example, a secondary TRP), a problem that the UE cannot receive important control information can occur.

[0235] To solve the above problem, a method of performing BFR only for a specific TRP can be applied. The operation of performing BFR only for a specific TRP can include a TRP-specific BFD operation, a TRP-specific BFRQ operation, an operation of receiving a response to the BFRQ from the base station, a BFR MAC-CE transmission operation, an operation of receiving a response to the BFR MAC-CE from the base station, and an operation of resetting the beam of the specific TRP to a new candidate beam.

[0236] First, the UE can perform a BFD operation only for a specific TRP (i.e., a TRP-specific BFD operation).

[0237] The UE can perform BFD on a CORESET group (or a BFD RS set) associated with a specific TRP to which important information such as system information is to be transmitted. At this time, the CORESET group associated with the specific TRP (or the BFD RS set) can be a pre-configured CORESET group (e.g., a CORESET group having a CORESET group ID of 0) or a CORESET group (or a BFD RS set) individually configured by the base station to perform BFD.

[0238] Specifically, the base station can implicitly configure (BFD) RS to the UE to perform BFD. That is, if the base station does not explicitly set (BFD) RS to perform BFD, the UE can perform BFD only on a (type D) QCL RS indicated by a TCI state corresponding to a CORESET group associated with a specific TRP.

[0239] Additionally or alternatively, the base station can explicitly configure one or more CORESET groups (or BFD RS sets) associated with a specific TRP to the UE to perform BFD. The UE can perform BFD in units of one or more configured CORESET groups (or BFD RS sets).

[0240] When it is detected that BF has occurred in a specific TRP (or one of the CORESET groups associated with the specific TRP), the UE can transmit a TRP-specific BFRQ to the base station.

[0241] Specifically, the base station can configure a BFRQ resource (e.g., a scheduling request (SR) PUCCH resource) to the UE. That is, when BF occurs in a specific TRP, the UE can transmit the configured BFRQ (e.g., SR PUCCH) to the base station. At this time, the UE can transmit the BFRQ to a TRP in which BF does not occur. Also, when transmitting the BFRQ, the UE can explicitly or implicitly report to the base station which BFD RS set (or CORESET group) is associated with the BFRQ.

[0242] In addition, the base station can configure a separate BFRQ resource for each TRP, but is not limited thereto, and a plurality of TRPs can be configured to share one BFRQ resource. For example, when performing BFR for an SCell, each TRP can share a BFRQ resource based on a plurality of spatial relation parameters.

[0243] The UE can receive a response to the BFRQ from the base station. Specifically, the UE can receive a response to the BFRQ including an uplink grant DCI from the base station that has received the BFRQ.

[0244] Also, the UE can transmit a BFR MAC-CE to the base station. Specifically, the UE can transmit the BFR MAC-CE to the base station through a PUSCH scheduled by the received uplink grant DCI. In this case, the BFR MAC-CE can include an ID of a component carrier (CC) in which BF occurs, information on whether a new candidate beam is found in the CC, an ID of the found new candidate beam, and information on a TRP ID (e.g., CORESET group ID or BFD RS set ID, etc.) in which BF occurs.

[0245] The UE can receive a response to the BFR MAC-CE from the base station. Specifically, the response to the BFR MAC-CE can be a DCI indicating that the BFR MAC-CE has been normally received. At this time, the DCI is a DCI transmitted when the base station successfully decodes the PUSCH, and can include at least one of a HARQ process ID, a new data indicator (NDI), a redundancy version (RV), and CGG transmission information (CBGTI).

[0246] The UE can reset a beam related to a TRP in which BF has occurred to a new candidate beam. Specifically, the DCI indicating that the BFR MAC-CE has been normally received is received from the base station, and after a certain time (e.g., 28 symbols), the UE can reset a beam (e.g., a PDDCH beam) related to a TRP that transmitted the DCI or a TRP that reported new candidate beam information through the BFR MAC-CE to a new candidate beam RS.

[0247] BFR operation when BF occurs in a specific TRP or all TRPs

[0248] The enhanced BFR operation as described above can include a BFR operation for one or more CCs / BWPs. When the BFR operation for one or more CCs / BWPs is performed, the BFR MAC-CE transmitted by the UE to the base station can include information indicating whether the BFR operation is a BFR operation for an SpCell (i.e., a PCell or a PSCell) (e.g., a BFR operation based on a contention-based RACH for the SpCell) or a BFR operation for a Scell, a list of CCs / BWPs in which BF occurs (a list of CCs / BWPs in which beam failure occurs), information on whether a new candidate beam RS is found in each of the CCs / BWPs in which BF occurs, and a new candidate beam RS ID found when a new candidate beam RS is found in the CC / BWP, etc.

[0249] Here, if the size of the UL-SCH allocated to the UE is not sufficient to transmit the BFR MAC-CE, the UE can transmit the BFR MAC-CE omitting some information (i.e., a truncated BFR MAC-CE) to the base station. For example, in the truncated BFR MAC-CE, information on whether a new candidate beam RS is found in the list of CCs / BWPs in which BF has occurred can be omitted, but is not limited thereto. The type of information omitted can be variously configured.

[0250] Additionally or alternatively, as described above, the UE can perform a BFR operation for each TRP (i.e., a TRP-specific BFR operation). The present disclosure includes embodiments of a BFR scheme that can be applied to both a case where BF occurs for a specific TRP (e.g., a specific CORESET group or a specific BFD RS group) (hereinafter, referred to as "event 1 occurrence") and a case where BF occurs for all TRPs in a specific frequency band (e.g., a CC / BWP) (hereinafter, referred to as "event 2 occurrence"). Here, event 2 can be considered a BF event defined in the existing UE operation (e.g., Rel-15 / 16) because BF occurs in the corresponding CC / BWP (i.e., BF occurs in all TRPs of the CC / BWP).

[0251] Embodiment 1

[0252] When event 1 or event 2 occurs, the UE can use a BFRQ resource commonly configured for event 1 and event 2. In addition, the UE can report information on whether event 1 and / or event 2 has occurred to the base station.

[0253] Here, the BFRQ resource configured commonly for the event 1 and the event 2 can be a resource for BFR for one or more CCs / BWPs. For example, the BFRQ resource can include a PUCCH resource configured for BFRQ use (i.e., a BFRQ-PUCCH resource). In this case, the BFRQ-PUCCH resource can use the same PUCCH format as a scheduling request (SR) included in uplink control information (UCI), and an SR ID for the BFRQ can be configured.

[0254] The UE can reduce the overhead of the reserved uplink resource by using the BFRQ resource configured commonly for the event 1 and the event 2.

[0255] Here, the event 1 can be divided into detailed events according to an index of a TRP (e.g., a CORESET group or a BFD RS group) in which BF occurs. For example, the event 1 can be divided into event 1-1, which is a case where BF occurs for TRP 1, and event 1-2, which is a case where BF occurs for TRP 2. That is, information about whether the event 1 has occurred can be divided into detailed events according to the occurrence of BF for each TRP and reported.

[0256] In addition, information about whether the event 2 has occurred can be omitted based on the configuration of the information about whether the event 1 has occurred. For example, when BF occurs for two TRPs, the UE can omit information about whether the event 2 occurs by reporting information that the event 1-1 and the event 1-2 have occurred.

[0257] Additionally or alternatively, when the event 1 occurs for a specific CC / BWP and the event 2 occurs for another specific CC / BWP, the information about the event 1 or / and the event 2 can include an indicator indicating that both the event 1 and the event 2 have occurred.

[0258] For example, when the indicator is included in the information about whether the event 1 and / or the event 2 has occurred, the UE can report at least one of information about CCs / BWPs in which the event 1 and the event 2 have occurred, information about whether a new candidate beam RS is found in the CC / BWP in which BF occurs, or new candidate beam RS ID information to the base station separately.

[0259] In addition, the information about whether the event 1 and / or the event 2 has occurred can be reported by being included in a predefined BFR MAC-CE. That is, the UE can report to the base station by including the information about whether the event 1 and / or the event 2 has occurred on a MAC-CE for BFR use.

[0260] Additionally or alternatively, a separate MAC-CE can be defined for each event 1 (or detailed event according to event 1) and event 2. Thus, when a specific event occurs, the UE can report the MAC-CE corresponding to the specific event (i.e., the MAC-CE defined in the specific event) to the base station. And, the base station can determine what event has occurred through the format / header of the reported MAC-CE.

[0261] For example, when event 2 occurs, the UE can report a predefined BFR MAC-CE to the base station, or can report a MAC-CE separately defined in event 2 to the base station.

[0262] And, when the MAC-CE is separately defined for each event, the TRP for reporting the MAC-CE for a specific event can be separately limited (or configured). For example, when the MAC-CE is reported as a TRP in which BF has occurred, there is a high probability that the corresponding MAC-CE cannot be decoded by the TRP. Thus, the UE can be limited (or configured) to report the corresponding MAC-CE only to the TRP in which BF has not occurred.

[0263] In addition, the (TRP-specific) MAC-CE generation / triggering method can be changed so that the TRP that limits (configures) the UE to report the (TRP-specific) MAC-CE.

[0264] For example, the (TRP-specific) BFR MAC-CE can be generated / triggered only when there is an UL-SCH (i.e., if available) for the TRP in which BF has not occurred.

[0265] As another example, the BFR MAC-CE can be generated / triggered when scheduling DCI / grant is received from the TRP in which BF has not occurred (e.g., CORESET group, etc.) (i.e., when BF is implicitly detected), or when PDCCH / PDSCH TCI is included in the DL RS on the TRP in which BF has not occurred (i.e., when BF is explicitly detected) (TRP-specific).

[0266] In reporting information to the base station about whether event 1 or / and event 2 has occurred, the UE can define whether each event has occurred as a separate state (i.e., a BF state). In addition, the UE can report the BF state corresponding to each CC / BWP in which BF has occurred (using the same BFRQ resource to perform BFR) to the base station.

[0267] Here, the bit width of the BF status can vary according to the number of TRPs. For example, when the number of TRPs is 3, the BF status can consist of 2 bits as shown in Table 6 below. In Table 6, BF occurs in TRP #x can mean that BF occurs in CORESET group #x or BFD RS group #x.

[0268] [Table 6]

[0269] BF status Description 00 Event 2 (if BF occurs in all TRPs) 01 Event 1-1 (i.e., if BF occurs only in TRP #0) 10 Event 1-2 (i.e., if BF occurs only in TRP #1) 11 Event 1-3 (i.e., if BF occurs only in TRP #2)

[0270] As another example, the UE can use a BF bitmap instead of a BF status to indicate whether each event has occurred. Specifically, the UE can map values indicating whether BF has occurred to each bit of the BF bitmap in the order of the TRP ID of a specific CC / BWP. For example, if the bit corresponding to TRP #1 in the BF bitmap is 1, this means that BF has occurred for TRP #1, and when the bit is 0, this can mean that BF has not occurred for TRP #1. Also, if BF has occurred for all TRPs (i.e., event 2 has occurred), since 1 is mapped to each bit included in the BF bitmap, a separate identifier for indicating whether event 2 has occurred can not be needed.

[0271] Additionally or alternatively, the UE can map values indicating whether BF has occurred to each bit of the BF bitmap in the order of the CORESET pool index value associated with the CORESET of a specific CC / BWP, and report the BF bitmap to the base station.

[0272] As described above, when reporting the BF status or the BF bitmap for each CC / BWP (or the CC / BWP in which BF has occurred) to the base station, the BFR MAC-CE reported to the base station can include information on whether the BFR operation is a BFR operation for a SpCell or a BFR operation for a Scell, a list of CC / BWPs in which BF has occurred, a BF status or a BF bitmap for the CC / BWP in which BF has occurred, information on whether a new candidate beam RS is found in each of the CC / BWPs in which BF has occurred, and a new candidate beam RS ID found when a new candidate beam RS is found in the CC / BWP, etc.

[0273] At this time, with respect to the list of CC / BWPs in which BF has occurred, the UE can report not only the CC / BWP in which beam failure has occurred when event 2 has occurred, but also the CC / BWP in which beam failure has occurred with respect to the CC / BWP in which event 1 has occurred.

[0274] Additionally or alternatively, the BF status and the BF bitmap can be information indicating whether BF has occurred in all of the CC / BWPs reported by the UE, rather than information reported for each CC / BWP.

[0275] At this time, the BFR MAC-CE reported to the base station can include information on whether the BFR operation is a BFR operation for the SpCell or a BFR operation for the SCell, a BF status or a BF bitmap, a list of CCs / BWPs in which BF has occurred, information on whether a new candidate beam RS is found in each CC / BWP in which BF has occurred, and a new candidate beam RS ID found when a new candidate beam RS is found in the CC / BWP, etc.

[0276] In this case, the list of CCs / BWPs in which BF has occurred can include only a BF status in which BF has occurred or a list of CCs / BWPs of an event reported through a BF bitmap. For example, when a BF status or a BF bitmap is used to report that BF has occurred for TRP #0, the list of CCs / BWPs in which BF has occurred can include only a list of CCs / BWPs in which BF has occurred for TRP #0.

[0277] Additionally or alternatively, the BF status or the BF bitmap can be extended so that a plurality of BF statuses or BF bitmaps indicating whether BF has occurred for each CC / BWP can be reported together. For example, the BF status can be extended to include a status indicating that event 1 has occurred in a specific CC / BWP and event 2 has occurred in another CC / BWP.

[0278] At this time, the BFR MAC-CE reported to the base station can include information on whether the BFR operation is a BFR operation for the SpCell or a BFR operation for the SCell, a BF status or a BF bitmap, a list of CCs / BWPs in which BF has occurred, information on whether a new candidate beam RS is found in each CC / BWP in which BF has occurred, and a new candidate beam RS ID found when a new candidate beam RS is found in the CC / BWP, etc.

[0279] Here, the size of the BF status or the BF bitmap can vary. Accordingly, a field indicating the size of the BF status or the BF bitmap can be added to the BFR MAC-CE.

[0280] As another example, the size of the BF status or the BF bitmap can be fixed according to the number of events that occur / reportable. At this time, if no event occurs (or no BF occurs), it can be configured to include a predefined value indicating that no event has occurred in the field indicating the BF status or the BF bitmap in the BFR MAC-CE.

[0281] In addition, the CC / BWP list in which the BF has occurred can be determined according to the number of events reported through the BF status or the BF bitmap information. For example, when the case of "BF occurs and all TRPs in TRP#0 occur" is reported using the BF status or the BF bitmap, the CC / BWP list in which the BF occurs can include the CC / BWP list in which the BF of TRP#0 occurs and the CC / BWP list in which the BF of all TRPs occurs.

[0282] Also, the field size of the information about whether a new candidate beam RS is found in each CC / BWP in which the BF has occurred and the field size of the new candidate beam RS ID can be configured as the number of CC / BWPs in which even one event has occurred, or can be separately configured according to events that have occurred.

[0283] For example, assuming that when carrier aggregation (CA) is applied, CC#0 to CC#4 are configured, the BF for TRP#0 occurs in CC#0 and CC#3, and the BF for all TRPs occurs in CC#1. The information about whether a new candidate beam RS is found in each CC / BWP in which the BF occurs and the new candidate beam RS ID can be configured in the order of CC#0, CC#1, and CC#3, or can be configured for each event. Here, configuring the information for each event can mean configuring and reporting information about CC#0 and CC#3 corresponding to event 1 (i.e., information about whether a new candidate beam RS is found in CC#0 and CC#3 and a new candidate beam RS ID), and configuring and reporting information about CC#1 corresponding to event 2.

[0284] Embodiment 1-1

[0285] The size of the CC / BWP list reported by the UE can be configured as the number of CC / BWPs in which an event can occur among all CC / BWPs in which the BFD is performed when the shared BFRQ resource is used.

[0286] When CA is applied, all CCs can be configured as MTRP or STRP, but some CCs can be configured as MTRP and some CCs can be configured as STRP. If the latter is configured (i.e., some CCs are configured as MTRP and some other CCs are configured as STRP) and BF occurs for all TRPs, BF occurrence in some CCs configured as STRP can be considered as BF occurrence in a specific TRP (i.e., occurrence of event 1) or BF occurrence in all TRPs (i.e., occurrence of event 2). That is, the size of the CC / BWP list reported by the UE can vary depending on whether BF occurrence in some CCs configured as STRP is considered as specific TRP BF occurrence or all TRP BF occurrence. Accordingly, embodiment 1-1 includes a method of configuring the size of the entire CC / BWP list to be reported by the UE as the number of CCs / BWPs in which a specific event can occur.

[0287] Specifically, when BF occurs in a specific TRP (e.g., a BFD RS set), the size of the CC / BWP list reported by the UE can be determined by the number of CCs / BWPs including a specific TRP ID (or a BFD RS set ID) among all CCs / BWPs in which BFD is performed / configured when sharing a BFRQ resource.

[0288] Also, if BF occurs in all TRPs, the size of the CC / BWP list reported by the UE can be determined by 1) the total number of CCs / BWPs in which BFD is performed / configured when sharing a BFRQ resource or 2) the number of CCs / BWPs including all BFD RS set IDs (i.e., including BFD RS sets commonly configured for each TRP) among the entire CC / BWP.

[0289] BF occurring for a specific TRP (event 1 occurs) in a CC / BWP configured only for the specific TRP (i.e., STRP) can be interpreted as the same as BF occurring for all TRPs (event 2 occurs) in the CC / BWP. Accordingly, the size of the CC / BWP list to be reported by the UE can be determined depending on whether "BF occurrence for all TRPs" is interpreted in a narrow sense (method 2) or in a broad sense (method 1).

[0290] For example, assume that, among CC#0 to CC#5, CC#0 to CC#4 are configured for a BFD RS set for TRP#0 and CC#3 to CC#5 are configured for a BFD RS set for TRP#1.

[0291] When the size of the CC list to be reported by the UE is determined based on the total number of CCs in which BFD is performed / configured (i.e., according to the above-described method 1)), the size of the CC list for event 2 can be 6 (CC#0 to CC#5). Also, when the size of the CC list to be reported by the UE is determined by the number of CCs including all BFD RS set IDs among all CCs (i.e., the above-described method 2)), the size of the CC list for event 2 can be 2 (CC#3 and CC#4).

[0292] When the above-described method 1) is applied, the CC size for event 1 can be configured to be 2 (CC#3 and CC#4). At this time, the occurrence of BF in CCs (CC#0, CC#1, CC#2, and CC#5) operating in the STRP can be interpreted as event 2 occurring.

[0293] Also, when the method 2) is applied, the CC size for event 1 can be configured to be 6 (CC#0 to CC#5). At this time, the BF report for CCs operating in the STRP can be interpreted as a TRP-specific BF report. For example, the size of the CC list for BF of TRP#0 in event 1 is 5 (CC#0 to CC#4), and the size of the CC list for BF of TRP#1 in event 1 can include 3 (CC#3 to CC#5).

[0294] In examples 1 and 1-1, a case in which the UE uses the BFRQ resource commonly configured for event 1 and event 2 has been described. However, this is only an embodiment, and the UE can use the BFRQ resource (e.g., PUCCH resource / sequence) separately configured for each of event 1 and event 2. In order to reduce the size of the CC / BWP list reported by the UE even when the method of using the separately configured BFRQ resource is applied to each of event 1 and event 2, the above-described embodiment 1-1 can be applied.

[0295] Embodiment 2

[0296] The UE can use different BFRQ resources for event 1 (or detailed events of event 1) and event 2. Also, the size of the CC / BWP list for each BFRQ resource can be defined as the number of CCs / BWPs in which a specific event can occur among all CCs / BWPs in which BFD is performed / configured while sharing the BFRQ resource.

[0297] As described in Embodiment 1-1, the size of the CC / BWP list for the BFRQ resource report for Event 2 can be determined as 1) the total number of CCs / BWPs in which BFD is performed / configured while sharing the BFRQ resource, or 2) the number of CCs / BWPs including all BFD RS set IDs (i.e., including the BFD RS set commonly configured for each TRP) among the entire CC / BWP.

[0298] For example, it is assumed that, among CC#0 to CC#5, CC#0 to CC#4 are configured for the BFD RS set of TRP#0, and CC#3 to CC#5 are configured for the BFD RS set of TRP#1.

[0299] When the size of the CC list to be reported by the UE is determined based on the total number of CCs in which BFD is performed / configured (i.e., according to the above-described method 1)), the size of the CC list for Event 2 can be 6 (CC#0 to CC#5). And, when the size of the CC list to be reported by the UE is determined by the number of CCs including all BFD RS set IDs among all CCs (i.e., the above-described method 2)), the size of the CC list for Event 2 can be 2 (CC#3 and CC#4).

[0300] When the above-described method 1) is applied, the CC size for Event 1 can be configured as 2 (CC#3 and CC#4). At this time, the occurrence of BF in the CCs (CC#0, CC#1, CC#2, and CC#5) operating in the STRP can be interpreted as the occurrence of Event 2.

[0301] And, when the method 2) is applied, the CC size for Event 1 can be configured as 6 (CC#0 to CC#5). At this time, the BF report for the CCs operating in the STRP can be interpreted as a TRP-specific BF report. For example, the size of the CC list for the BF of TRP#0 in Event 1 is 5 (CC#0 to CC#4), and the size of the CC list for the BF of TRP#1 in Event 1 can include 3 (CC#3 to CC#5).

[0302] Embodiments 1 and 2 have been described with reference to a plurality of TRPs, but this can be equally applied to transmission through a plurality of panels. In addition, Embodiments 1 and 2 can be independently applied, but can be applied in combination with the above-described BFR operation.

[0303] Figure 8 is a diagram for explaining a beam failure recovery operation of a UE according to an embodiment of the disclosure.

[0304] Based on detecting a beam failure (BF) in at least one of a plurality of resource groups, the UE can transmit a beam failure recovery request (BFRQ) to the base station (S810).

[0305] Here, the resource group can include at least one of a control resource set (CORESET) group or a beam failure detection (BFD) reference signal (RS) group. Each of the CORESET group or the BFD RS group can correspond to a TRP. For example, CORESET group 1 or BFD RS group 1 can correspond to TRP 1, and CORESET group 2 or BFD RS group 2 can correspond to TRP 2.

[0306] Here, the CORESET group includes one or more CORESETs, and the resource group can be configured based on transmission configuration indicator (TCI) states configured for the one or more CORESETs. That is, the BFD RS for performing beam failure detection can be implicitly configured based on the TCI states configured for the CORESETs. Also, the UE can detect beam failure in at least one resource group through the configured BFD RS.

[0307] The transmission of the BFRQ to the base station can mean the transmission of the BFRQ to the base station through the BFRQ resource. In this case, the BFRQ resource can be commonly configured in at least one frequency band (e.g., a component carrier (CC) or a bandwidth part). Specifically, based on the detection of beam failure in a specific resource group or a plurality of resource groups, the UE can transmit the BFRQ to the base station through the BFRQ resource commonly configured for the beam failure in the specific resource group and the beam failure in the plurality of resource groups.

[0308] In another embodiment of the disclosure, when beam failure is detected in a specific resource group and when beam failure is detected in a plurality of resource groups, the BFRQ resource corresponding to each resource group can be different. For example, a first BFRQ resource can be configured for beam failure in a specific resource group, and a second BFRQ resource can be configured for beam failure in a plurality of resource groups. Also, based on the occurrence of beam failure in the specific resource group, the UE can transmit a first BFRQ of the BFRQ to the base station through the first BFRQ resource among the BFRQ resources. Also, based on the occurrence of beam failure in the plurality of resource groups, the UE can transmit a second BFRQ of the BFRQ to the base station through the second BFRQ resource different from the first BFRQ resource among the BFRQ resources.

[0309] In addition, the UE can be configured (or allocated) with available uplink resources (e.g., UL-SCH resources, PUSCH resources, etc.). Based on the presence of the available uplink resources, the UE can transmit information related to the beam failure to the base station through the available uplink resources, without performing the operation of transmitting the BFRQ to the base station and the operation of receiving the response to the BFRQ from the base station. That is, when the available uplink resources are pre-allocated to the UE, the UE can omit the BFRQ transmission operation and the BFRQ response reception operation, and transmit information related to the beam failure to the base station using the allocated available uplink resources.

[0310] The UE can receive a response to the BFRQ from the base station (S820). The response to the BFRQ can include an uplink grant. The UE can transmit a PUSCH scheduled by the DCI including the uplink grant to the base station.

[0311] The UE can transmit information related to the beam failure to the base station (S830). Here, the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected. For example, the information related to the beam failure can include information on whether the beam failure is detected in a specific TRP or the beam failure is detected in a plurality of TRPs including the specific TRP.

[0312] Also, whether the beam failure is detected in a specific TRP or whether the beam failure is detected in a plurality of TRPs can be defined as a separate BF state. The bit width of the BF state can vary according to the number of TRPs. As another example, whether the beam failure is detected in a specific TRP or whether the beam failure is detected in a plurality of TRPs can be defined as a separate BF bitmap.

[0313] In addition, the information related to the beam failure can include at least one of a type of a cell in which the beam failure is detected, index information of at least one frequency band in which the beam failure is detected, information on whether there is a new candidate beam RS in the at least one frequency band in which the beam failure is detected, or information indicating a new candidate beam RS based on the presence of the candidate beam RS.

[0314] Here, the type of the cell in which the beam failure is detected can indicate whether the cell in which the beam failure is detected is an SpCell or an SCell. In addition, the information on the new candidate beam RS can include ID information of the new candidate beam RS when the new candidate beam RS is present in the at least one frequency band in which the beam failure is detected.

[0315] Also, based on detecting the beam failure in the plurality of resource groups, a size of at least one frequency band in which the beam failure is detected can be determined based on a size of the entire frequency band in which the BFD is performed or a size of a frequency band including an identification (ID) of the plurality of resource groups among the entire frequency band in which the BFD is performed.

[0316] For example, it is assumed that, among CC#0 to CC#5, CC#0 to CC#4 are configured for a BFD RS set of TRP#0, CC#3 to CC#5 are configured for a BFD RS set of TRP#1, and a beam failure occurs in all TRPs.

[0317] When the size of the CC in which the beam failure is detected to be reported by the UE is determined based on the total number of CCs in which the BFD is performed, the size of the CC in which the beam failure is detected can be configured as 6 (CC#0 to CC#5). Also, when the size of the CC in which the beam failure is detected to be reported by the UE is determined by the number of CCs including the plurality of resource group IDs among all CCs in which the BFD has been performed, the size of the CC in which the beam failure occurs can be configured as 2 (CC#3 and CC#4).

[0318] Additionally or alternatively, for each of at least one frequency band in which the beam failure is detected, the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected.

[0319] Specifically, the information related to the beam failure can indicate a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected in a first frequency band among the at least one frequency band, and indicate a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected in a second frequency band among the at least one frequency band.

[0320] For example, it is assumed that a beam failure is detected in component carriers (CCs) 1 and 2. At this time, the information related to the beam failure can indicate whether the beam failure is detected in a specific TRP or a plurality of TRPs including the specific TRP in each of the CCs 1 and 2. Also, whether the beam failure is detected in the specific TRP or the plurality of TRPs including the specific TRP can be indicated by a BF state or a BF bitmap, as described above.

[0321] The information related to the beam failure can be included in one MAC-CE (e.g., a BFR MAC-CE) or a plurality of MAC-CEs configured for BFR and transmitted to the base station. Specifically, information indicating a specific resource group in which the beam failure is detected or a plurality of resource groups in which the beam failure is detected can be included in one MAC-CE and transmitted to the base station.

[0322] Here, at least one of the following can be included and transmitted in a single MAC-CE: 1) a type of a cell in which beam failure is detected, 2) index information of at least one frequency band in which beam failure is detected, 3) information on whether there is a new candidate beam RS in at least one frequency band in which beam failure is detected, or 4) information (e.g., an ID of a new candidate beam RS) indicating a new candidate beam RS based on the presence of the candidate beam RS. However, it is not limited thereto, and one MAC-CE can include only information indicating a specific resource group in which beam failure is detected or a plurality of resource groups in which beam failure is detected, and the above 1) to 4) can be separately transmitted to the base station.

[0323] Additionally or alternatively, information related to beam failure can be included in a plurality of MAC-CEs and transmitted to the base station. Specifically, when beam failure is detected in a specific resource group and when beam failure is detected in a plurality of resource groups, a MAC-CE corresponding to each resource group can be separately defined.

[0324] For example, the plurality of MAC-CEs can include a first MAC-CE and a second MAC-CE. And, based on detecting beam failure in a specific resource group, information related to beam failure can be included in the first MAC-CE and transmitted to the base station. And, based on detecting beam failure in a plurality of resource groups, information related to beam failure can be included in the second MAC-CE and transmitted to the base station.

[0325] Additionally or alternatively, information related to beam failure can be transmitted to a resource group in which beam failure is not detected. For example, based on information related to beam failure being included in one MAC-CE (e.g., a BFR MAC-CE) or a plurality of MAC-CEs (e.g., a first MAC-CE or a second MAC-CE), the UE can transmit one MAC-CE or a plurality of MAC-CEs to a resource group in which beam failure is not detected. In the case of a resource group in which beam failure is detected, information included in the MAC-CE can not be decoded. Accordingly, the UE can transmit one MAC-CE or a plurality of MAC-CEs including information related to beam failure to a resource group in which beam failure is not detected.

[0326] Figure 9 is a diagram for describing a beam failure recovery operation of a base station according to an embodiment of the disclosure.

[0327] Based on detecting beam failure (BF) in at least one of a plurality of resource groups, the base station can receive a beam failure recovery request (BFRQ) from the UE (S910).

[0328] Here, detailed examples of the resource group and the BFRQ resource are described with reference to FIGS. 9A and 9B. Figure 8The example described in step S810 of FIG. 8A is the same as that described in step S810 of FIG. 8B, and thus overlapping parts will be omitted.

[0329] The base station can transmit a response to the BFRQ to the UE (S920). The response to the BFRQ can include an uplink grant. The base station can receive, from the UE, a PUSCH scheduled by a DCI including the uplink grant.

[0330] The base station can receive, from the UE, information related to the beam failure (S930). Here, examples of the information related to the beam failure are the same as those described in relation to Figure 8 The example described in step S820 of FIG. 8A is the same as that described in step S820 of FIG. 8B, and thus overlapping parts will be omitted.

[0331] Specifically, the base station can receive, from the UE, one MAC-CE (e.g., a BFR MAC-CE) or a plurality of MAC-CEs configured for BFR use including the information related to the beam failure.

[0332] Here, examples related to one MAC-CE or a plurality of MAC-CEs are the same as those described in relation to Figure 8 The example described in step S830 of FIG. 8A is the same as that described in step S830 of FIG. 8B, and thus overlapping parts will be omitted.

[0333] Figure 10 is a diagram for describing a signaling procedure of a network side and a UE according to the present disclosure.

[0334] Figure 10 An example of signaling between a network side and a UE in an M-TRP case to which the above-described embodiments of the present disclosure (e.g., a combination of one or more of Embodiment 1, Embodiment 1-1, Embodiment 2, or detailed embodiments thereof) can be applied is illustrated. Here, the UE / network side is exemplary and can be replaced by various devices described with reference to Figure 11 . Figure 10 is for ease of description and does not limit the scope of the present disclosure. In addition, some steps shown in Figure 10 may be omitted according to circumstances and / or configurations, etc. In addition, the above-described uplink transmission and reception operations, M-TRP-related operations, etc. can be referred to or used for Figure 10 the operations of the network side / UE in

[0335] In the following description, the network side can be one base station including a plurality of TRPs, or can be one cell including a plurality of TRPs. Alternatively, the network side can include a plurality of RRHs (Remote Radio Heads) / RRUs (Remote Radio Units). In an example, ideal / non-ideal backhaul can be configured between TRP 1 and TRP 2 configuring the network side. In addition, the following description is described based on a plurality of TRPs, but it can be equally extended and applied to transmission through a plurality of panels / cells, and can be extended and applied to transmission through a plurality of RRHs / RRUs, etc.

[0336] In addition, in the following description, it is described based on "TRP", but as described above, the TRP can be applied by replacing with an expression such as a panel, an antenna array, a cell (e.g., a macro cell / a small cell / a pico cell, etc.), a TP (Transmission Point), a base station (gNB, etc.), etc. As described above, the TRP can be classified according to information (e.g., a CORESET index, an ID) on a CORESET group (or a CORESET pool). In an example, when one UE is configured to perform transmission and reception with a plurality of TRPs (or cells), this can mean that a plurality of CORESET groups (or CORESET pools) are configured for one UE. The configuration on such a CORESET group (or CORESET pool) can be performed through higher layer signaling (e.g., RRC signaling, etc.). In addition, the base station can generally mean an object that performs transmission and reception of data with a terminal. For example, the base station can be a concept including at least one TP (Transmission Point), at least one TRP (Transmission and Reception Point), etc. In addition, the TP and / or the TRP can include a panel of the base station, a transmission and reception unit, etc.

[0337] The UE can receive configuration information from the network side through / using TRP 1 and / or TRP 2 (S105). The configuration information can include system information (SI), scheduling information, CSI-related configuration (e.g., CSI reporting configuration, CSI-RS resource configuration), etc. The configuration information can include information related to network side configuration (i.e., TRP configuration), resource allocation information related to MTRP-based transmission and reception, etc. The configuration information can be transmitted through a higher layer (e.g., RRC, MAC CE). In addition, when the configuration information is predefined or configured, the corresponding step can be omitted.

[0338] For example, as in the above embodiments (e.g., Embodiment 1, Embodiment 1-1, Embodiment 2, or a combination of one or more detailed examples), the configuration information may include CORESET-related configuration information (e.g., ControlResourceSetIE). CORESET-related configuration information may include a CORESET-related ID (e.g., controlResourceSetID), an index of the CORESET pool used for the CORESET (e.g., CORESETPoolIndex), the time / frequency resource configuration of the CORESET, TCI information related to the CORESET, etc. For example, the configuration information may include information related to beam management / BFR, as described in the above embodiments (e.g., Embodiment 1, Embodiment 1-1, Embodiment 2, or a combination of one or more detailed embodiments).

[0339] For example, the UE in stage S105 above ( Figure 11 The 100 or 200 in the middle comes from the network side ( Figure 11 The operation of receiving configuration information (200 or 100) can be described below. Figure 11 This is achieved using the devices described. For example, refer to... Figure 11 At least one processor 102 can control at least one transceiver 106 and / or at least one memory 104, etc., to receive configuration information, and at least one transceiver 106 can receive configuration information from the network side.

[0340] The UE can transmit reference signals for UL transmission to the network side via / using TRP 1 and / or TRP 2 (S110). For example, the UE can receive RS 1 and / or RS 2 for beam management / BFD to the network side via / using TRP 1 and / or TRP 2.

[0341] For example, the UE in stage S110 above ( Figure 11 The 100 or 200 in the reference signal will be sent to the network side. Figure 11 The operation of 200 or 100 in the above can be described below. Figure 11 This is achieved using the devices described. For example, refer to... Figure 11 At least one processor 102 can control at least one transceiver 106 and / or at least one memory 104, etc., to transmit reference signals, and at least one transceiver 106 can transmit reference signals to the network side.

[0342] The UE can perform beam management / BFR based on the RS 1 and / or RS 2 through / using the TRP 1 and / or TRP 2 from the network side (S115). For example, the beam management / BFR performing method can be performed based on the above-described embodiments (e.g., Embodiment 1, Embodiment 1-1, Embodiment 2, or a combination of one or more of detailed examples thereof). For example, the UE can measure / estimate a hypothetical BLER based on a reception quality of the RS 1 and / or RS 2, and can determine the BF accordingly.

[0343] For example, the operation of performing beam management / BFR by the UE (100 or 200) of the above-described step S115 can be implemented by an apparatus of Figure 11 Figure 11 For example, referring to Figure 11 , the one or more processors 102 can control the one or more memories 104 to perform the beam management / BFR operation.

[0344] The UE can transmit a beam management / BFR report (e.g., BFRQ) to the network side through / using the TRP 1 and / or TRP 2 (S120). In this case, a beam management / BFR report (e.g., BFRQ, etc.) for the TRP 1 and a beam management / BFR report (e.g., BFRQ, etc.) for the TRP 2 can be transmitted respectively, or can be combined into one. In addition, the UE is configured to transmit a report (e.g., BFRQ, etc.) for beam management / BFR to a representative TRP (e.g., TRP 1), and transmission of a report (e.g., BFRQ, etc.) for beam management / BFR to another TRP (e.g., TRP 2) can be omitted. Alternatively, the UE can be configured to transmit a BFR report (e.g., BFRQ, etc.) in the same TRP as the TRP in which the beam failure occurs. Alternatively, the UE can be configured to transmit a BFR report (e.g., BFRQ, etc.) to a TRP other than the TRP in which the beam failure occurs.

[0345] For example, the beam management / BFR report (e.g., BFRQ, etc.) can be performed based on the above-described embodiments (e.g., Embodiment 1, Embodiment 1-1, Embodiment 2, or a combination of one or more of detailed examples thereof). For example, the case when the BF occurs for a specific TRP (e.g., Event 1) and the case when the BF occurs for all TRPs (e.g., Event 2) can be reported respectively. In addition, the BFR can be performed for a plurality of serving cells / BWPs. For example, the beam management / BFR report (e.g., BFRQ, etc.) can be transmitted based on a BFR MAC CE.

[0346] ​For example, the BFR MAC CE can include whether it is a BFR for a SpCell or a BFR for an SCell, a list of CCs / BWPs in which the beam failure occurs, whether a new candidate beam RS is found in the CC / BWP in which the BF occurs, a new candidate beam RS ID found in the CC / BWP in which the BF occurs, and indication information for the case when the BF occurs for a specific TRP (e.g., event 1) and / or when the BF occurs for all TRPs (e.g., event 2), etc. For example, the indication information can be configured in the form of an indication bitmap or any one of pre-defined states.

[0347] For example, the network side that receives the report / BFRQ for the BF from the UE through / using the TRP 1 and / or the TRP 2 can transmit new BM / BFR-related RS information for beam recovery to the UE.

[0348] For example, the UE (100 / 200) of step S120 described above Figure 11 may transmit a report on beam management / BFR (e.g., BFRQ, etc.) to the network side (100 / 200) described above Figure 11 may be implemented by the apparatus described below Figure 11 . For example, referring to Figure 11 , the one or more processors 102 can control the one or more transceivers 106 and / or the one or more memories 104 to transmit a report for beam management / BFR, etc. (e.g., BFRQ, etc.), and the one or more transceivers 106 can transmit the beam management / BFR report (e.g., BFRQ, etc.) to the network side.

[0349] Through the beams determined based on the above-described procedure, the UE can receive DCI 1 and data 1 scheduled by the corresponding DCI 1 from the network side through / using the TRP 1. In addition, the UE can receive DCI 2 and data 2 scheduled by the corresponding DCI 2 from the network side through / using the TRP 2. The DCI (e.g., DCI 1, DCI 2) and the data (e.g., data 1, data 2) can be transmitted through a control channel (e.g., PDCCH, etc.) and a data channel (e.g., PDSCH, etc.), respectively. For example, the DCI 1 can be received based on a first CORESET configured to 0 or not configured, and the DCI 2 can be received based on a second CORESET configured to 1. For example, the DCI (e.g., DCI 1, DCI 2) and / or the data (e.g., data 1, data 2) can include control information / data related to the operations described in the above-described methods (e.g., embodiment 1, embodiment 1-1, embodiment 2, or a combination of one or more detailed examples thereof).

[0350] As described above, the above network side / UE signaling and embodiments (e.g., embodiment 1, embodiment 1-1, embodiment 2, or a combination of one or more detailed embodiments thereof) can be implemented by a first device 100 to be referred to as a Figure 11 apparatus implementation described. For example, the network side (e.g., TRP 1 / TRP 2) can correspond to the first device 100, and the UE can correspond to the second device 200, and in some cases vice versa can be considered.

[0351] For example, the above network side / UE signaling and operations (e.g., embodiment 1, embodiment 1-1, embodiment 2, or a combination of one or more detailed embodiments thereof) can be processed by Figure 11 one or more processors (e.g., 102, 202), and the above network side / UE signaling and operations (e.g., embodiment 1, embodiment 1-1, embodiment 2, or a combination of one or more detailed embodiments thereof) can be stored in the form of instructions / programs (e.g., instructions, executable code) in one or more memories (e.g., 104, 204) of Figure 11 at least one processor (e.g., 102 and 202) of Figure 11

[0352] Figure 11

[0353] Figure 11 is a diagram illustrating a block diagram of a wireless communication device according to an embodiment of the disclosure.

[0354] Referring to Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 Figure 11 , the first device 100 and the second device 200 can transmit and receive wireless signals through a variety of radio access technologies (e.g., LTE, NR).

[0355] ​The first device 100 can include one or more processors 102 and one or more memories 104, and can additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 can control the memory 104 and / or the transceiver 106 and can be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. For example, the processor 102 can generate first information / signal by processing information in the memory 104, and then transmit a wireless signal including the first information / signal through the transceiver 106. Also, the processor 102 can receive a wireless signal including second information / signal through the transceiver 106, and then store information obtained by signal processing of the second information / signal in the memory 104. The memory 104 can be connected to the processor 102 and can store a variety of information related to the operation of the processor 102. For example, the memory 104 can store software code including commands for performing all or part of the processes controlled by the processor 102 or for performing the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. Here, the processor 102 and the memory 104 can be part of a communication modem / circuitry / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 106 can be connected to the processor 102 and can transmit and / or receive a wireless signal through the one or more antennas 108. The transceiver 106 can include a transmitter and / or a receiver. The transceiver 106 can be used together with an RF (Radio Frequency) unit. In the present disclosure, a wireless device can mean a communication modem / circuitry / chip.

[0356] The second device 200 can include one or more processors 202 and one or more memories 204, and can additionally include one or more transceivers 206 and / or one or more antennas 208. The processor(s) 202 can control the memory(s) 204 and / or the transceiver(s) 206 and can be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. For example, the processor(s) 202 can generate third information / signals by processing information in the memory(s) 204, and then transmit wireless signals including the third information / signals through the transceiver(s) 206. Also, the processor(s) 202 can receive wireless signals including fourth information / signals through the transceiver(s) 206, and then store information obtained by signal processing of the fourth information / signals in the memory(s) 204. The memory(s) 204 can be connected to the processor(s) 202 and can store various information related to operations of the processor(s) 202. For example, the memory(s) 204 can store software code including commands for executing all or part of the processes controlled by the processor(s) 202 or for executing the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. Here, the processor(s) 202 and the memory(s) 204 can be part of a communication modem / circuitry / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver(s) 206 can be connected to the processor(s) 202 and can transmit and / or receive wireless signals through the one or more antennas 208. The transceiver(s) 206 can include a transmitter and / or a receiver. The transceiver(s) 206 can be used together with an RF unit. In the present disclosure, a wireless device can mean a communication modem / circuitry / chip.

[0357] Hereinafter, the hardware elements of the devices 100, 200 will be described in more detail. They are not limited thereto, and one or more protocol layers can be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 can implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts included in the present disclosure. One or more processors 102, 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102, 202 can generate a signal (e.g., a baseband signal) including the PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure to provide the same to one or more transceivers 106, 206. One or more processors 102, 202 can receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 and obtain the PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure.

[0358] The one or more processors 102, 202 can be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 can be implemented by hardware, firmware, software, or a combination thereof. In an example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) can be included in the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure can be implemented by using firmware or software and the firmware or software can be implemented as including modules, procedures, functions, etc. The firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure can be included in the one or more processors 102, 202 or can be stored in the one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure can be implemented in the form of codes, commands, and / or command sets by firmware or software.

[0359] One or more memories 104, 204 can be connected to one or more processors 102, 202 and can be capable of storing data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 can be configured with ROM, RAM, EPROM, flash memory, a hard disk drive, a register, a cash memory, a computer-readable storage medium, and / or a combination thereof. One or more memories 104, 204 can be positioned inside and / or outside one or more processors 102, 202. In addition, one or more memories 104, 204 can be connected to one or more processors 102, 202 through various technologies such as a wired or wireless connection.

[0360] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operational flowcharts, etc. of the disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc. disclosed in the disclosure from one or more other devices. For example, one or more transceivers 106, 206 can be connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 can be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 can be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc. disclosed in the disclosure through one or more antennas 108, 208. In the disclosure, one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers 106, 206 can convert received wireless signals / channels, etc. from RF band signals to baseband signals to process received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 can convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals to RF band signals. Accordingly, one or more transceivers 106, 206 can include (analog) oscillators and / or filters.

[0361] The above-described embodiments of the present disclosure can be combined in a predetermined form to assemble elements and features of the present disclosure. Unless explicitly mentioned otherwise, each element or feature should be considered optional. Each element or feature can be implemented in a form that is not combined with other elements or features. Furthermore, embodiments of the present disclosure can include combining partial elements and / or features. The order of operations described in embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced with corresponding elements or features of other embodiments. It is clear that embodiments can include combining claims without explicit dependency, or can be included as new claims by modification after the application.

[0362] It is obvious to those skilled in the art that the present disclosure can be implemented in other specific forms without departing from the essential characteristics of the present disclosure. Therefore, the above detailed description should not be interpreted in a limiting manner in every aspect, but should be considered as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all variations within the scope of equivalents of the present disclosure are included in the scope of the present invention.

[0363] The scope of the present disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to the methods of various embodiments in a device or computer, and non-transitory computer-readable media that store such software or commands, etc., and can be executed in a device or computer. Commands that can be used to program a processing system to perform the features described in the present disclosure can be stored in a storage medium or computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium can include a high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid state storage devices, but is not limited thereto, and can include a non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices located remotely from the processor. The memory or, alternatively, the non-volatile memory devices in the memory include a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any one machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using results from embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0364] Here, the wireless communication technology implemented in the wireless devices 100, 200 of the present disclosure can include narrowband Internet of Things for low-power communication and LTE, NR, and 6G. Here, for example, the NB-IoT technology can be an example of LPWAN (Low Power Wide Area Network) technology, can be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-mentioned names. In addition or alternatively, the wireless communication technology implemented in the wireless devices 100, 200 of the present disclosure can perform communication based on LTE-M technology. Here, in an example, the LTE-M technology can be an example of LPWAN technology and can be referred to by various names such as eMTC (enhanced Machine Type Communication) or the like. For example, the LTE-M technology can be implemented in at least any one of various standards including 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-bandwidth limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-mentioned names. In addition or alternatively, the wireless communication technology implemented in the wireless devices 100, 200 of the present disclosure can include at least any one of ZigBee, Bluetooth, and low-power wide area network (LPWAN) considering low-power communication, and it is not limited to the above-mentioned names. In an example, the ZigBee technology can generate a PAN (Personal Area Network) related to small / low-power digital communication based on various standards such as IEEE 802.15.4 or the like, and can be referred to by various names.

[0365] [Industrial applicability]

[0366] The method proposed by the present application is mainly described by taking the application to 3GPP LTE / LTE-A, 5G system as an example, but can also be applied to various wireless communication systems other than 3GPP LTE / LTE-A, 5G system.

Claims

1. A method for a user equipment (UE) to perform beam fault recovery (BFR) in a wireless communication system, comprising: Receive radio resource control (RRC) signaling from the base station related to the BFR procedure for configuring multiple serving cells with two beam fault detection-reference signals (BFD-RS) sets; Based on the detection of a beam fault in at least one of the two BFD-RS sets configured for at least one of the plurality of serving cells, the BFR procedure is performed on at least one of the two BFD-RS sets based on the RRC signaling; as well as Send an enhanced BFR Media Access Control-Control Element (MAC-CE) to the base station. The enhanced MAC CE includes: i) information relating to whether the beam fault was detected for a single BFD-RS set or for both BFD-RS sets; ii) information relating to whether the beam fault was detected for at least one of the two BFD-RS sets configured for a special cell (SpCell) among the plurality of serving cells; and iii) information relating to whether the beam fault was detected for a first secondary cell (SCell) among the plurality of serving cells.

2. The method according to claim 1, wherein: The enhanced BFR MAC-CE includes information indicating whether the index of the candidate beam RS exists in the enhanced BFR MAC-CE.

3. The method according to claim 1, wherein: Each of the two BFD-RS sets includes at least one BFD-RS associated with at least one Transport Configuration Indicator (TCI) state configured for each of the multiple Control Resource Sets (CORESETs).

4. The method according to claim 1, wherein: The RRC signaling includes information related to the beam fault recovery timer and information related to the candidate beam RS list.

5. The method according to claim 2, wherein: The candidate beam RS includes RSs from the at least one candidate beam list that have a quality value greater than or equal to a predefined value.

6. A user equipment (UE) for performing beam fault recovery (BFR) in a wireless communication system, comprising: At least one transceiver, the at least one transceiver being used to transmit and receive wireless signals; as well as At least one processor, said at least one processor being used to control the one or more transceivers, Wherein, the at least one processor is configured to: The at least one transceiver receives radio resource control (RRC) signaling from the base station related to the BFR procedure for configuring multiple serving cells with two beam fault detection-reference signals (BFD-RS) sets; Based on the detection of a beam fault in at least one of the two BFD-RS sets configured for at least one of the plurality of serving cells, the BFR procedure is performed on at least one of the two BFD-RS sets based on the RRC signaling; and The enhanced BFR Media Access Control-Control Element (MAC-CE) is transmitted to the base station via the at least one transceiver. The enhanced BFR MAC-CE includes: i) information relating to whether the beam fault was detected for a single BFD-RS set or for all of the two BFD-RS sets; ii) information relating to whether the beam fault was detected for at least one of the two BFD-RS sets configured for a special cell (SpCell) among the plurality of serving cells; and iii) information relating to whether the beam fault was detected for a first secondary cell (SCell) among the plurality of serving cells.

7. The UE according to claim 6, wherein: The enhanced BFR MAC-CE includes information indicating whether the index of the candidate beam RS exists in the enhanced BFR MAC-CE.

8. The UE according to claim 6, wherein: Each of the two BFD-RS sets includes at least one BFD-RS associated with at least one Transport Configuration Indicator (TCI) state configured for each of the multiple Control Resource Sets (CORESETs).

9. The UE according to claim 6, wherein: The RRC signaling includes information related to the beam fault recovery timer and information related to the candidate beam RS list.

10. The UE according to claim 7, wherein: The candidate beam RS includes RSs from the at least one candidate beam list that have a quality value greater than or equal to a predefined value.

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