Method and device for evaluating radio link quality in a wireless communication system

Abstract

A method and apparatus for evaluating radio link quality in a wireless communication system are disclosed. The method for evaluating radio link quality according to one embodiment of the disclosure can include the steps of receiving configuration information related to a control resource set (CORESET) from a base station, and evaluating radio link quality based on one or more reference signals (RSs) for a CORESET related to a physical downlink control channel (PDCCH) monitored with a terminal. The radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which a quasi co-location (QCL) related to a spatial reception parameter for the CORESET has been set.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for evaluating radio link quality 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 demanded 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 evaluating radio link quality for performing a beam failure detection or radio link monitoring operation.

[0006] In addition, another technical object of the disclosure is to provide a method and apparatus for determining a reference signal for evaluating radio link quality.

[0007] The technical objects to be achieved 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] The method for evaluating radio link quality in a wireless communication system according to one aspect of the disclosure can include receiving configuration information related to a control resource set (CORESET) from a base station and evaluating radio link quality based on one or more reference signals (RSs) for a CORESET related to a physical downlink control channel (PDCCH) monitored by a terminal. The radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which a quasi co-location (QCL) related to a spatial reception parameter for the CORESET is configured.

[0010] A terminal evaluating radio link quality in a wireless communication system according to an additional aspect of the disclosure can include one or more transceivers for transmitting and receiving wireless signals, and one or more processors controlling the one or more transceivers. The one or more processors can be configured to receive, from a base station, configuration information related to a control resource set (CORESET), and evaluate radio link quality based on one or more reference signals (RSs) for the CORESET related to a physical downlink control channel (PDCCH) monitored by the terminal. The radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which quasi co-location (QCL) related to spatial reception parameters for the CORESET is configured.

[0011] One or more non-transitory computer-readable media storing one or more instructions to control a device evaluating radio link quality according to an additional aspect of the disclosure can receive, from a base station, configuration information related to a control resource set (CORESET), and evaluate radio link quality based on one or more reference signals (RSs) for the CORESET related to a physical downlink control channel (PDCCH) monitored by the terminal. The radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which quasi co-location (QCL) related to spatial reception parameters for the CORESET is configured.

[0012] A processing apparatus configured to control a terminal evaluating radio link quality in a wireless communication system according to an additional aspect of the disclosure can include one or more processors and one or more computer memories operatively connected to the one or more processors and storing instructions that, based on being executed by the one or more processors, perform operations. The operations can include receiving, from a base station, configuration information related to a control resource set (CORESET), and evaluating radio link quality based on one or more reference signals (RSs) for the CORESET related to a physical downlink control channel (PDCCH) monitored by the terminal. The radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which quasi co-location (QCL) related to spatial reception parameters for the CORESET is configured.

[0013] A method of supporting evaluation of radio link quality by a terminal in a wireless communication system according to an additional aspect of the disclosure can include transmitting, to the terminal, configuration information related to a control resource set (CORESET). The terminal can evaluate the radio link quality based on one or more reference signals (RSs) for a CORESET related to a physical downlink control channel (PDCCH) monitored by the terminal, and can evaluate the radio link quality based on one or more reference signals among a plurality of reference signals for which a quasi co-location (QCL) related to a spatial reception parameter for the CORESET is configured.

[0014] A base station for supporting evaluation of radio link quality by a terminal according to an additional aspect of the disclosure can include one or more transceivers for transmitting and receiving wireless signals, and one or more processors that control the one or more transceivers. The one or more processors can be configured to transmit, to the terminal, configuration information related to a control resource set (CORESET). The terminal can evaluate the radio link quality based on one or more reference signals (RSs) for a CORESET related to a physical downlink control channel (PDCCH) monitored by the terminal, and can evaluate the radio link quality based on one or more reference signals among a plurality of reference signals for which a quasi co-location (QCL) related to a spatial reception parameter for the CORESET is configured.

[0015] Advantageous Effects

[0016] According to embodiments of the disclosure, when a plurality of reference signals are configured for one control resource set, particularly, reference signals for which a QCL (quasi co-location) related to a spatial reception parameter is configured, a reference signal for evaluating radio link quality can be determined.

[0017] In addition, according to embodiments of the disclosure, even when a plurality of base stations / TRPs / panels / beams participate in PDCCH transmission, beam failure detection and radio link monitoring operations for beam failure recovery can be performed.

[0018] Effects that can be achieved by the disclosure are not limited to the above-mentioned effects and other effects not described herein can be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are included as part of the detailed description to understand the disclosure, provide embodiments of the disclosure and describe technical features of the disclosure through the detailed description.

[0020] Figure 1 FIG. 1 illustrates a structure of a wireless communication system to which the disclosure can be applied.

[0021] Figure 2A frame structure in a wireless communication system to which the disclosure of the present disclosure can be applied is illustrated.

[0022] Figure 3 A resource grid in a wireless communication system to which the disclosure of the present disclosure can be applied is illustrated.

[0023] Figure 4 A physical resource block in a wireless communication system to which the disclosure of the present disclosure can be applied is illustrated.

[0024] Figure 5 A slot structure in a wireless communication system to which the disclosure of the present disclosure can be applied is illustrated.

[0025] Figure 6 A physical channel used in a wireless communication system to which the disclosure of the present disclosure can be applied, and a general signal transmission and reception method using the same are illustrated.

[0026] Figure 7 FIG. is a diagram illustrating a beam failure recovery operation of a Pcell in a wireless communication system to which the disclosure of the present disclosure can be applied.

[0027] Figure 8 A signaling method for a method for evaluating radio link quality according to an embodiment of the disclosure is illustrated.

[0028] Figure 9 FIG. is a diagram illustrating an operation of a terminal for a method for evaluating radio link quality according to an embodiment of the disclosure.

[0029] Figure 10 FIG. is a diagram illustrating an operation of a base station for supporting radio link quality evaluation according to an embodiment of the disclosure.

[0030] Figure 11 FIG. is a diagram illustrating a block configuration of a wireless communication device according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed by the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to represent the only embodiments in which the disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the disclosure. However, it will be apparent to those skilled in the art that the disclosure can be implemented without these specific details.

[0032] In some cases, known structures and devices can be omitted, or can be shown in a block diagram form to facilitate the prevention of obscuring the concept of the disclosure based on the core function of each structure and device.

[0033] 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 existing therebetween as well as a direct connection relationship. In addition, in the disclosure, the term "comprising" or "having" specifies 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.

[0034] In the disclosure, the term "comprising" or "having" specifies 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.

[0035] The terms used in the disclosure are intended to describe specific embodiments, not to limit the claims. As used in the description of embodiments and the appended claims, the singular form is intended to include the plural form, unless the context clearly dictates otherwise. The term "and / or" used in the 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 specified, " / " between words in the disclosure has the same meaning as "and / or".

[0036] The disclosure describes a wireless communication network or a wireless communication system, and operations performed in the wireless communication network can be performed in a process in which a device (e.g., a base station) controlling the 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.

[0037] In the disclosure, a transmission or reception channel includes the meaning of transmitting or receiving information or a signal through the corresponding channel. For example, transmitting a control channel means transmitting control information or a control signal through the control channel. Similarly, transmitting a data channel means transmitting data information or a data signal through the data channel.

[0038] 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.

[0039] The following description can be used for various radio access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA can be implemented by such as UTRA (Universal Terrestrial Radio Access), or CDMA2000. TDMA can be implemented by such as a radio technology of GSM (Global System for Mobile communication) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented by such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (Evolved UTRA), etc. 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.

[0040] For a clearer description, description is made 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 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 background technology, 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.

[0041] 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.

[0042] For 3GPP NR, 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) can be referred to.

[0043] Abbreviations of terms that can be used in the disclosure are defined as follows.

[0044] -BM: Beam Management

[0045] -CQI: Channel Quality Indicator

[0046] -CRI: Channel State Information-Reference Signal Resource Indicator

[0047] –CSI: Channel State Information

[0048] -CSI-IM: Channel State Information-Interference Measurement

[0049] -CSI-RS: Channel State Information-Reference Signal

[0050] -DMRS: Demodulation Reference Signal

[0051] –FDM: Frequency Division Multiplexing

[0052] - FFT: Fast Fourier Transform

[0053] - IFDMA: Interleaved Frequency Division Multiple Access

[0054] - IFFT: Inverse Fast Fourier Transform

[0055] - L1-RSRP: Layer 1 Reference Signal Received Power

[0056] - L1-RSRQ: Layer 1 Reference Signal Received Quality

[0057] - MAC: Medium Access Control

[0058] - NZP: Non-Zero Power

[0059] - OFDM: Orthogonal Frequency Division Multiplexing

[0060] - PDCCH: Physical Downlink Control Channel

[0061] - PDSCH: Physical Downlink Shared Channel

[0062] - PMI: Precoding Matrix Indicator

[0063] - RE: Resource Element

[0064] - RI: Rank Indicator

[0065] - RRC: Radio Resource Control

[0066] - RSSI: Received Signal Strength Indicator

[0067] - Rx: Reception

[0068] - QCL: Quasi Co-Location

[0069] - SINR: Signal to Interference and Noise Ratio

[0070] - SSB (or SS / PBCH Block): Synchronization Signal Block (including PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal) and PBCH (Physical Broadcast Channel))

[0071] - TDM: Time Division Multiplexing

[0072] - TRP: Transmission and Reception Point

[0073] - TRS: Tracking Reference Signal

[0074] - Tx: Transmission

[0075] - UE: User Equipment

[0076] - ZP: Zero Power

[0077] Overall system

[0078] 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 a plurality of devices and things is also one of 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, 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 representing an example of a 5G RAT.

[0079] A new RAT system including NR uses an OFDM transmission method or a transmission method similar thereto. The new RAT system can follow OFDM parameters different from those of 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.

[0080] A numerology corresponds to one subcarrier spacing in a frequency domain. Different numerologies can be defined as a reference subcarrier spacing is scaled by an integer N.

[0081] Figure 1 The structure of a wireless communication system to which the present disclosure is applicable is illustrated.

[0082] Reference Figure 1 , the NG-RAN is configured with gNBs that provide the 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 control plane (RRC) protocol termination for UE. The gNBs are interconnected with each other over an Xn interface. In addition, 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.

[0083] Figure 2 The frame structure in a wireless communication system to which the present disclosure is applicable is illustrated.

[0084] 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). Also, 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. Also, various frame structures according to multiple numerologies can be supported in the NR system.

[0085] 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.

[0086] [Table 1]

[0087] μ Δf = 2 μ · 15 [kHz]] CP 0 15 Normal 1 30 Normal 2 60 Normal, extended 3 120 Normal 4 240 Normal

[0088] The NR supports multiple numerologies (or subcarrier spacings (SCSs)) for supporting various 5G services. For example, when the SCS is 15 kHz, a wide area of a legacy cellular band is supported; and when the SCS is 30 kHz / 60 kHz, a dense city, lower latency, and a wider carrier bandwidth are supported; and when the SCS is 60 kHz or more, a bandwidth exceeding 24.25 GHz is supported to overcome phase noise. The NR band is defined as two types of frequency ranges (FR1, FR2). The FR1, FR2 can be configured as in Table 2 below. In addition, the FR2 can mean a millimeter wave (mmW).

[0089] [Table 2]

[0090] 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

[0091] Regarding a frame structure in the NR system, the size of various fields in the time domain is expressed as a multiple of a time unit of T c = 1 / (Δf max · N f ). Here, Δf max is 480·10 3 Hz, and N f is 4096. Downlink and uplink transmissions are configured (organized) as radio frames having a duration T f = 1 / (Δf max · N f / 100)· T c = 10 ms. Here, a radio frame is configured with 10 subframes, each having T sf = (Δf max · N f / 1000)· T cIn this case, there may be one frame set for uplink and one frame set for downlink. In addition, the transmission in the uplink frame numbered i from the terminal should start T earlier than the corresponding downlink frame in the corresponding terminal. TA =(N TA +N TA,offset )T c For subcarrier spacing configuration μ, the time slots in the subframe are n s μ ∈{0,...,N slot subframe,μ -1} and are numbered in increasing order in the radio frame by n s,f μ ∈{0,...,N slot frame,μ -1}. A time slot is configured with N symb slot consecutive OFDM symbols, and N symb slot Determined by CP. Time slot n in a subframe s μ The beginning of the OFDM symbol n in the same subframe s μ N symb slot All terminals may not perform transmission and reception at the same time, which means that all OFDM symbols of a downlink time slot or an uplink time slot may not be used. Table 3 shows the number of OFDM symbols per time slot in a normal CP (N symb slot ), the number of time slots per radio frame (N slot frame,μ ) and the number of time slots per subframe (N slot subframe,μ ), 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 the extended CP.

[0092] [Table 3]

[0093] 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

[0094] [Table 4]

[0095] μ N symb slot ]]> <![CDATA[N slot frame,μ ]]> N slot subframe,μ ]]> 2 12 40 4

[0096] Figure 2 This is an example of μ=2 (SCS is 60kHz), see Table 3, 1 subframe can include 4 time slots. Figure 2The number of slots that can be included in one 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. Hereinafter, the physical resources that can be considered in the NR system will be described in detail.

[0097] 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 carrying a symbol in one antenna port can be inferred from a channel carrying a symbol of another antenna port, 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.

[0098] Figure 3 A resource grid in a wireless communication system to which the disclosure can be applied is illustrated.

[0099] Reference Figure 3 , a resource grid is illustratively described as being configured with N RB μ N sc RB subcarriers, and one subframe is configured with 14·2 μ OFDM symbols, but is not limited thereto. In the NR system, a transmitted signal is described by one or more resource grids of N μ N symb (μ) OFDM symbols and configured with N RB μ N sc RB subcarriers. Here, N RB μ ≤ N RB max,μ . N RB max,μ denotes a maximum transmission bandwidth, which can be different between uplink and downlink and between numerologies. In this case, one resource grid can be configured per μ and antenna port p. Each element of the resource grid for μ and antenna port p is called a resource element and is uniquely identified by the index pair (k, l'). Here, k = 0,..., N RB μ N sc RB - 1 is an index in the frequency domain, and l' = 0,..., 2 μ Nsymb (μ) -1 refers to the symbol position in a subframe. When referring to a resource element in a time slot, the index pair (k, l) is used. Here, l = 0,..., N symb μ -1. The resource element pair (k, l') 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 no specific antenna port or numerology is specified, the indices p and μ can be dropped, and the complex value can be a k,l' (p) or a k,l' In addition, a resource block (RB) is defined as N sc RB = 12 consecutive subcarriers in the frequency domain.

[0100] A point serves as a common reference point of the resource block grid and is obtained as follows.

[0101] - offsetToPointA of a primary cell (PCell) downlink indicates the 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 a subcarrier spacing of 15 kHz for FR1 and 60 kHz for FR2.

[0102] - absoluteFrequencyPointA indicates the frequency location of point A, expressed in ARFCN (absolute radio frequency channel number).

[0103] For a subcarrier spacing configuration μ, the 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 "point A". The common resource block number n CRB μ The relationship between the resource element (k, l) and the subcarrier (n, i) is given as Equation 1 below.

[0104] [Equation 1]

[0105]

[0106] In Equation 1, k is defined with respect to point A such that k = 0 corresponds to the subcarrier centered at point A. The physical resource blocks are numbered from 0 to N BWP,i size,μ - 1 and i is the number of the BWP. The physical resource block n PRB and the common resource block n CRB The relationship between them is given by Equation 2 below.

[0107] [Equation 2]

[0108]

[0109] N BWP,i start,μ is a common resource block where a BWP starts with respect to common resource block 0.

[0110] Figure 4 FIG. illustrates a physical resource block in a wireless communication system to which the disclosure can be applied. Also, Figure 5 FIG. illustrates a slot structure in a wireless communication system to which the disclosure can be applied.

[0111] 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 includes 6 symbols for an extended CP.

[0112] A carrier includes a plurality of subcarriers in the frequency domain. An RB (Resource Block) is defined as a plurality (e.g., 12) of contiguous subcarriers in the frequency domain. A BWP (Bandwidth Part) is defined as a plurality of contiguous (physical) resource blocks in the 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.

[0113] 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 a plurality of 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 a maximum bandwidth. In consideration of this, a base station can instruct a terminal to operate only in a partial bandwidth, rather than in the full bandwidth of a wideband CC, and for convenience, the corresponding partial bandwidth is defined as a bandwidth part (BWP). A BWP can be configured with contiguous RBs on the frequency axis and can correspond to one numerology (e.g., subcarrier spacing, CP length, slot / micro-slot duration).

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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).

[0119] 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 a PDCCH and a corresponding PDSCH (S604 and S606). A contention-based RACH can additionally perform a contention resolution procedure.

[0120] 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 a PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and the format varies according to its use purpose.

[0121] Meanwhile, control information transmitted by the terminal to the base station through an 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 a 3GPP LTE system, the terminal can transmit the above-described control information of CQI / PMI / RI, etc. through a PUSCH and / or a PUCCH.

[0122] Table 5 represents an example of a DCI format in an NR system.

[0123] [Table 5]

[0124]

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] Quasi co-location (QCL)

[0133] The antenna ports are defined such that the channel that transmits a symbol in an antenna port can be inferred from the channel that transmits other symbols in the same antenna port. When a property of the channel that carries a symbol in one antenna port can be inferred from the channel that carries a symbol in another antenna port, it can be said that the 2 antenna ports are in a QC / QCL (Quasi Co-Location) relationship.

[0134] Here, the channel properties include at least one of delay spread, Doppler spread, frequency / Doppler shift, average received power, received timing / average delay, or spatial RX parameter. Here, the spatial Rx parameter means a spatial (Rx) channel property parameter such as an angle of arrival.

[0135] The terminal can be configured in a list of up to M TCI-State configurations in a higher layer parameter PDSCH-Config to decode PDSCH according to a detected PDCCH with an intended DCI for the corresponding terminal and a given serving cell. M depends on the UE capability.

[0136] Each TCI-State includes parameters for configuring a quasi co-location relationship between the ports of one or two DL reference signals and the DM-RS of PDSCH.

[0137] The quasi co-location relationship is configured by a higher layer parameter qcl-Type1 for the first DL RS and qcl-Type2 for the second DL RS if configured. For both DL RSs, the QCL types are not the same regardless of whether the reference is the same DL RS or different DL RSs.

[0138] The quasi co-location type corresponding to each DL RS is given by a higher layer parameter qcl-Type of QCL-Info and can take one of the following values.

[0139] - "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}

[0140] - "QCL-TypeB": {Doppler shift, Doppler spread}

[0141] - "QCL-TypeC": {Doppler shift, average delay}

[0142] - "QCL-TypeD": {spatial Rx parameters}

[0143] For example, when the target antenna port is a specific NZP CSI-RS, it can be indicated / configured that the corresponding NZP CSI-RS antenna port is quasi-collocated with a specific TRS with respect to QCL-TypeA and is quasi-collocated with a specific SSB with respect to QCL-TypeD. A terminal receiving such indication / configuration can measure the delay value in the QCL-TypeA TRS by using Doppler reception for the reception of the corresponding NZP CSI-RS and apply the Rx beam for the reception of the QCL-TypeD SSB to the reception of the corresponding NZP CSI-RS.

[0144] A UE can receive an activation command through MAC CE signaling for mapping up to 8 TCI states to the codepoints of the DCI field "Transmission Configuration Indication".

[0145] Beam failure recovery

[0146] In performing a DL / UL beam management procedure, a beam mismatch problem can occur according to a configured beam management period. In particular, when a terminal moves or rotates or when a wireless channel environment changes due to movement of surrounding objects (for example, a beam is blocked to change an LoS (Line of Sight) environment into a non-LoS environment), an optimal DL / UL beam pair can change. Due to such a change, when tracking fails in a beam management procedure that is usually performed as indicated by a network, a beam failure event can be considered to have occurred. A terminal can determine whether such a beam failure event has occurred through reception quality of a downlink reference signal (RS). Also, a report message for such a case or a message for a beam recovery request (referred to as a BFRQ (Beam Failure Recovery Request) message) should be transmitted from the terminal. A base station that receives such a beam failure recovery request message can perform beam recovery for beam recovery through various procedures such as beam RS transmission, beam report request, etc. This series of beam recovery procedures is referred to as a beam failure recovery (BFR). The version 15 NR has standardized a BFR (Beam Failure Recovery) procedure for a primary cell (PCell) or a primary secondary cell (PScell) (both collectively referred to as a special cell (SpCell)) based on a contention-based PRACH resource that has existed. As an operation in a serving cell, a corresponding BFR procedure is configured with a beam failure detection (BFD) procedure of a terminal, a BFRQ procedure, and a procedure in which the terminal monitors a response of a base station to the BFRQ.

[0147] Figure 7 FIG. 1 is a diagram illustrating a beam failure recovery operation for a Pcell in a wireless communication system to which the disclosure can be applied.

[0148] Hereinafter, a beam failure recovery operation is described with reference to Figure 7

[0149] 1) BFD (Beam Failure Detection)

[0150] When all PDCCH beams are below a predetermined quality value (Q_out), it can be said that a beam failure instance has occurred. Here, the quality is based on a hypothetical block error rate (BLER). In other words, this indicates a probability of demodulation failure of corresponding information when it is assumed that control information is transmitted to a corresponding PDCCH.

[0151] Here, one or more search spaces for monitoring a PDCCH can be configured to a terminal. Here, a beam can be differently configured per search space. In this case, this means a case in which all PDCCH beams of all search spaces are below a BLER threshold. As a method of a terminal determining a BFD RS, the following two methods are supported.

[0152] ​Implicit configuration of BFD RS: CORESET (Control Resource Set) ID (identifier) (a resource area where PDCCH can be transmitted) is configured in each search space. Also, RS information for QCL (Quasi Co-Location) of spatial RX parameters (e.g., CSI-RS resource ID, SSB ID) can be indicated / configured per CORESET ID. For example, the RS for QCL is indicated / configured by TCI (Transmission Configuration Information) indication in the NR standard. Here, the RS for QCL of spatial RX parameters (e.g., QCL Type D in TS 38.214) means that the base station informs the terminal to use (or can use) the same beam for receiving the corresponding spatial QCL RS (i.e., receive using the same spatial domain filter) when receiving the corresponding PDCCH DMRS. Finally, from the perspective of the base station, it is a method of informing the terminal to perform transmission by applying the same transmission beam or a similar transmission beam (e.g., when the beam direction is the same / similar, but the beam width is different) between the antenna ports of the spatial QCL. In other words, as described above, the terminal can determine the RS for QCL (Quasi Co-Location) of spatial RX parameters configured to the CORESET for PDCCH reception as the BFD RS (i.e., consider as "all PDCCH beams").

[0153] Explicit configuration of BFD RS: The base station can explicitly configure the beam RS to the terminal for the purpose (beam failure detection). In this case, the corresponding configured beam RS corresponds to "all PDCCH beams".

[0154] Whenever an event occurs in which the hypothetical BLER degradation based on the BFD RS measurement exceeds a certain threshold, the physical layer of the terminal informs the MAC sublayer of the occurrence of a beam failure instance (BFI). In the MAC sublayer of the terminal, when a certain number (e.g., the value of a higher layer parameter, beamFailureInstanceMaxCount) of BFIs occur within a certain time (i.e., within the BFD timer), it is determined (considered) that beam failure occurs and the related RACH operation is initiated.

[0155] The MAC object operates as follows:

[0156] 1> If a BFI is received from a lower layer (e.g., physical layer):

[0157] 2> Start or restart the BFD timer (beamFailureDetectionTimer);

[0158] 2> Increase (increment) the BFI counter (BFI_COUNTER) by 1;

[0159] 2> if the BFI counter (BFI_COUNTER) is equal to or larger than the maximum number of BFIs (beamFailureInstanceMaxCount):

[0160] 3> initiate a random access procedure in the SpCell (refer to the above random access related procedures).

[0161] 1> if the BFD timer (beamFailureDetectionTimer) expires; or

[0162] 1> if the BFD timer (beamFailureDetectionTimer), the maximum number of BFIs (beamFailureInstanceMaxCount), or any reference signal used for beam failure detection is reconfigured by a higher layer (e.g., RRC layer):

[0163] 2> set the BFI counter (BFI_COUNTER) to 0.

[0164] 1> if the random access procedure is successfully completed:

[0165] 2> set the BFI counter (BFI_COUNTER) to 0;

[0166] 2> stop the beam failure recovery timer (beamFailureRecoveryTimer) if configured;

[0167] 2> consider the beam failure recovery procedure successfully completed

[0168] 2) (PRACH-based) beam failure recovery request (BFRQ): new beam identification + PRACH transmission

[0169] As described in 1) beam failure detection (BFD), when a certain number or more of BFIs occur, the terminal can determine that a beam failure has occurred and perform a beam failure recovery operation. As an example of the beam failure recovery operation, a beam failure recovery request (BFRQ) operation based on a RACH procedure (i.e., PRACH) can be performed. The corresponding BFRQ procedure is described in detail below.

[0170] The base station can configure a list of RSs (e.g., candidateBeamRSList) corresponding to candidate beams that can be replaced when beam failure (BF) occurs through higher layer signaling (e.g., RRC) for the corresponding terminal. In addition, dedicated PRACH resources can be configured for the corresponding candidate beams. Here, the dedicated PRACH resources are non-contention-based PRACH (also referred to as contention-free PRACH) resources. If the terminal does not find an (appropriate) beam in the corresponding list, the terminal selects a contention-based PRACH among the pre-configured SSB resources and transmits it to the base station. The detailed procedure is as follows.

[0171] Step 1) The terminal finds a beam having a quality greater than a predetermined quality value (Q_in) among the RSs configured by the base station as a candidate beam RS set.

[0172] - If one beam RS exceeds the threshold, the terminal selects the corresponding beam RS.

[0173] - If multiple beam RSs exceed the threshold, the terminal selects any one of the corresponding beam RSs.

[0174] - If no beam exceeds the threshold, the terminal performs the following Step 2.

[0175] Here, the beam quality can be based on RSRP.

[0176] In addition, the RS beam set configured by the base station can include the following three cases. For example, all beam RSs in the RS beam set can be configured with SSB. Alternatively, all beam RSs in the RS beam set can be configured with CSI-RS resources. Alternatively, the beam RSs in the RS beam set can be configured with SSB and CSI-RS resources.

[0177] Step 2) The terminal finds a beam having a quality exceeding a predetermined quality value (Q_in) or more among the SSBs (associated with contention-based PRACH resources).

[0178] - If one SSB exceeds the threshold, the terminal selects the corresponding beam RS.

[0179] - If multiple SSBs exceed the threshold, the terminal selects any one of the corresponding beam RSs.

[0180] - If no beam exceeds the threshold, the terminal performs the following Step 3.

[0181] Step 3) The terminal selects any SSB among the SSBs (associated with contention-based PRACH resources).

[0182] The terminal transmits the PRACH resource and preamble directly or indirectly associated with and configured with the beam RS (CSI-RS or SSB) selected in the procedure to the base station.

[0183] - Here, the direct association configuration is used in the following case.

[0184] When contention-free PRACH resource and preamble is configured for a specific RS in the candidate beam RS set configured for BFR separately

[0185] When (contention-based) PRACH resource and preamble mapped one-to-one with SSB is configured, these SSBs are usually configured for other purposes such as random access

[0186] - Alternatively, here, the indirect association configuration is used in the following case.

[0187] When contention-free PRACH resource and preamble is not configured for a specific CSI-RS in the candidate beam RS set configured for BFR separately

[0188] Here, the terminal selects (contention-free) PRACH resource and preamble associated with SSB (i.e., in terms of spatial Rx parameter QCL (Quasi Co-Location) with the corresponding CSI-RS) designated as receivable with the same Rx beam as the corresponding CSI-RS.

[0189] 3) Monitoring the base station's response to BFRQ

[0190] - The terminal monitors the base station (gNB) response to the corresponding PRACH transmission.

[0191] Here, the response to contention-free PRACH resource and preamble is transmitted to the PDCCH masked by C-RNTI, and the response is received in the search space (SS) configured for BFR separately by RRC.

[0192] Here, the search space is configured for a specific CORESET (for BFR).

[0193] For the response to contention PRACH, the search space and CORESET (e.g., CORESET 0 or CORESET 1) configured for the general contention PRACH-based random access procedure are reused as is.

[0194] - If there is no response for a certain period of time, the process of 2) identifying and selecting a new beam and 3) monitoring the base station's response to BFRQ is repeated.

[0195] This procedure can be performed until the PRACH transmission reaches the pre-configured maximum number (N_max) or the configured timer (BFR timer) expires.

[0196] If the timer expires, the terminal stops the contention-free PRACH transmission, but can perform contention-based PRACH transmission through SSB selection until N_max is reached.

[0197] Improved beam failure recovery (Rel-16)

[0198] As described above, the version 15 NR standardizes the PRACH-based BFR procedure. However, due to the technical limitation that any SCell can not have an UL carrier in CA (Carrier Aggregation), and although there is an UL carrier but can not configure contention-based PRACH, it is applied only to PCell or PSCell. This limitation has a limitation, especially, when operating SCell in a high frequency band (e.g., 30 GHz) and operating PCell in a low frequency band (e.g., below 6 GHz), BFR can not be supported in a high frequency band where BFR is actually needed. For this reason, standardization of support for BFR on SCell is performed in the version 16 NR MIMO work item. So far, as a result of the standardization discussion, UL transmission to the corresponding SCell is not possible at least for DL-only SCell, and thus a (dedicated) PUCCH resource is planned to be configured, which is used to notify the base station of SCell beam failure occurring in SpCell and used to perform BFRQ for SCell. Hereinafter, for convenience, the PUCCH will be referred to as BFR-PUCCH.

[0199] As described above, the purpose of the BFR-PRACH standardized in version 15 is to transmit "beam failure occurrence + new beam RS (set) information" together to the base station. At the same time, the purpose of the BFR-PUCCH is to only notify "beam failure occurrence to SCell". And, which SCell the beam failure occurred to (e.g., CC index), whether there is a new beam for the corresponding SCell, and when there is a new beam (and the quality (e.g., RSRP or SINR) of the corresponding beam RS) can be reported as a subsequent MAC-CE (or UCI). Here, the subsequent beam report is not necessarily triggered all the time, and the SCell for which BFR is configured for the corresponding terminal can be deactivated after the base station receives the BFR-PUCCH. The reason for this design is because several tens of SCells can be associated with one PCell / PSCell, and because from the perspective of the base station, there can be many terminals sharing one PCell / PSCell UL, and even considering this case, it is desirable to minimize the amount of UL resources reserved for SCell BFRQ for each terminal in PCell / PSCell.

[0200] CORESET (control resource set)

[0201] The CORESET information element (IE) is used to configure time / frequency CORESETs for searching for downlink control information.

[0202] Table 6 shows the CORESET IE.

[0203] [Table 6]

[0204]

[0205]

[0206] Table 7 below is a table describing the fields in the CORESET IE.

[0207] [Table 7]

[0208]

[0209]

[0210] The CORESET identifier (ControlResourceSetId) IE is related to a short identifier (short ID) for identifying a CORESET in a serving cell. ControlResourceSetId = 0 identifies ControlResourceSet #0 configured by PBCH (MIB) and controlResourceSetZero (ServingCellConfigCommon). The ID space is for a BWP of a serving cell. The number of CORESETs per BWP is limited to 3 (including common CORESET and UE-specific CORESET). Table 8 illustrates the ControlResourceSetId IE.

[0211] [Table 8]

[0212]

[0213]

[0214] The CORESET zero (ControlResourceSetZero) IE is used to configure CORESET #0 of a first BWP. Table 9 illustrates the ControlResourceSetZero IE.

[0215] [Table 9]

[0216]

[0217] Multi-TRP (MTRP) URLLC

[0218] In the disclosure, DL MTRP-URLLC means that multiple TRPs transmit the same data (e.g., same TB) / DCI by using different layers / time / frequency resources. For example, TRP 1 transmits the same data / DCI in resource 1, while TRP 2 transmits the same data / DCI in resource 2. A UE configured with the DL MTRP-URLLC transmission method receives the same data / DCI by using different layers / time / frequency resources. Here, the UE is configured with which QCL RS / type (i.e., DL TCI (state)) should be used in the layer / time / frequency resource in which the same data / DCI is received from the base station. For example, when the same data / DCI is received in resource 1 and resource 2, the DL TCI state used in resource 1 and the DL TCI state used in resource 2 can be configured. The UE can achieve high reliability because it receives the same data / DCI through resource 1 and resource 2. This DL MTRP-URLLC can be applied to PDSCH / PDCCH.

[0219] In addition, in the disclosure, UL MTRP-URLLC means that multiple TRPs receive the same data / UCI (uplink control information) from a UE by using different layers / time / frequency resources. For example, TRP 1 receives the same data / DCI from the UE in resource 1, while TRP 2 receives the same data / DCI from the UE in resource 2, and shares the received data / DCI through a backhaul link connected between the TRPs. A UE configured with the UL MTRP-URLLC transmission method transmits the same data / UCI by using different layers / time / frequency resources. Here, the UE is configured from the base station with which Tx beam and which Tx power (i.e., UL TCI state) should be used in the layer / time / frequency resource in which the same data / DCI is transmitted. For example, when the same data / UCI is received in resource 1 and resource 2, the UL TCI state used in resource 1 and the UL TCI state used in resource 2 can be configured. This UL MTRP-URLLC can be applied to PUSCH / PUCCH.

[0220] In addition, in the disclosure, the meaning of using (or mapping) a certain TCI state (or TCI) when receiving data / DCI / UCI for any frequency / time / space resource is as follows. For DL, this can mean estimating a channel from DMRS by using QCL type and QCL RS indicated by the corresponding TCI state in the frequency / time / space resource, and receiving / demodulating data / DCI based on the estimated channel. In addition, for UL, this can mean transmitting / modulating DMRS and data / UCI by using a Tx beam and / or Tx power indicated by the corresponding TCI state in the frequency / time / space resource.

[0221] Here, the UL TCI state has Tx beam and / or Tx power information of the UE, and spatial relation information, etc. instead of the TCI state can be configured to the UE through other parameters. The UL TCI state can be directly indicated by the UL grant DCI or can mean spatial relation information of the SRS resource indicated by the SRI (SRS resource indicator) field of the UL grant DCI. Alternatively, it can mean an OL (open loop) Tx power control parameter (e.g., j: index of open loop parameters Po and alpha (α) (up to 32 parameter value sets per cell), q_d: index of DL RS resource for PL (path loss) measurement (up to 4 measurement per cell), l: closed loop power control process index (up to 2 processes per cell)) corresponding to the value indicated by the SRI field of the UL grant DCI.

[0222] In the disclosure, MTRP-eMBB means that multiple TRPs transmit other data (e.g., other TBs) by using different layers / time / frequency. The UE configured with the MTRP-eMBB transmission method is indicated multiple TCI states by DCI and assumes that data received by using the QCL RS of each TCI state is different data.

[0223] Meanwhile, by classifying and using RNTIs for MTRP-URLLC and RNTIs for MTRP-eMBB separately, the UE can understand whether MTRP URLLC transmission / reception or MTRP eMBB transmission / reception. In other words, when CRC masking of DCI is performed by using RNTI for URLLC, the UE considers it as URLLC transmission, and when CRC masking of DCI is performed by using RNTI for eMBB, the UE considers it as eMBB transmission. Alternatively, the base station can configure the UE with MTRP URLLC transmission / reception or MTRP eMBB transmission / reception through other new signaling.

[0224] In the disclosure, for convenience of description, the proposal is applied by assuming the cooperative transmission / reception between 2 TRPs, but it can be extended and applied in a 3 or more multi-TRP environment and also can be extended and applied in a multi-panel (i.e., a TRP corresponds to a panel) environment. In addition, different TRPs can be recognized as different TCI states by the UE. Thus, when the UE receives / transmits data / DCI / UCI by using TCI state 1, it means receiving / transmitting data / DCI / UCI from / to TRP 1.

[0225] In addition, in the disclosure, when a plurality of base stations (i.e., MTRP) repeatedly transmit the same PDCCH, it can mean that the same DCI is transmitted by a plurality of PDCCH candidates and it can mean that the same DCI is repeatedly transmitted by a plurality of base stations. The same DCI can mean two DCIs having the same DCI format / size / payload. Alternatively, although two DCIs have different payloads, they can be considered as the same DCI when the scheduling results are the same. For example, the TDRA (Time Domain Resource Allocation) field of the DCI relatively determines the slot / symbol position of data and the slot / symbol position of A / N (ACK / NACK) based on the reception time of the DCI, and if the DCI received at time n and the DCI received at time n+1 indicate the same scheduling result to the UE, the TDRA fields of the two DCIs are different, and thus, the DCI payloads are different. The repetition number R can be directly indicated by the base station to the UE or agreed upon by the base station and the UE. Alternatively, although the payloads of two DCIs are different and the scheduling results are not the same, they can be considered as the same DCI when the scheduling result of one DCI is a subset of the scheduling result of the other DCI. For example, when the same data is repeatedly transmitted N times by TDM, DCI 1 received before the first data indicates N times of data repetition, and DCI 2 received after the first data and before the second data indicates N-1 times of data repetition. The scheduling data of DCI 2 becomes a subset of the scheduling data of DCI 1 and the two DCIs are scheduling for the same data, so in this case, they can be considered as the same DCI.

[0226] In addition, in the disclosure, when a plurality of base stations (i.e., MTRP) partially transmit the same PDCCH, it means that one DCI is transmitted by one PDCCH candidate and some resources defined for the PDCCH candidate are transmitted by TRP 1 and the remaining resources are transmitted by TRP 2.

[0227] Additionally, in the present disclosure, when a UE repeatedly transmits the same PUSCH so that multiple base stations (i.e., MTRP) can receive it, this can mean that the UE transmits the same data through multiple PUSCHs. Here, each PUSCH can be optimized for the UL channel of a different TRP and transmitted. For example, when a UE repeatedly transmits the same data through PUSCH 1 and 2, PUSCH 1 is transmitted by using UL TCI state 1 for TRP 1, here link adaptation such as precoder / MCS, etc. can also be applied / scheduled in values optimized for the channel of TRP 1. PUSCH 2 is transmitted by using UL TCI state 2 for TRP 2, and link adaptation such as precoder / MCS, etc. can also be applied / scheduled in values optimized for the channel of TRP 2. The repeatedly transmitted PUSCH 1 and 2 in this case can be transmitted at different times so as to be TDMed, FDMed, SDMed.

[0228] Additionally, in the present disclosure, when a UE partially transmits the same PUSCH so that multiple base stations (i.e., MTRP) will receive it, this means that the UE transmits one data through one PUSCH, but the resources allocated to the PUSCH can be partitioned to optimize and transmit it to the UL channels of different TRPs. For example, when a UE transmits the same data through a 10-symbol PUSCH, the data is transmitted in the first 5 symbols by using UL TCI state 1 for TRP 1, and here, link adaptation such as precoder / MCS, etc. can also be applied / scheduled in values optimized for the channel of TRP 1. The remaining data is transmitted in the remaining 5 symbols by using UL TCI state 2 for TRP 2, and here, link adaptation such as precoder / MCS, etc. can also be applied / scheduled in values optimized for the channel of TRP 2. In this example, the transmission for TRP 1 and the transmission for TRP 2 are TDMed by dividing one PUSCH into time resources, but it can be transmitted by other FDM / SDM methods.

[0229] Similar to the PUSCH transmission described above, a UE can repeatedly transmit or partially transmit the same PUCCH so that multiple base stations (i.e., MTRP) can receive the PUCCH.

[0230] Method for BFD (beam failure detection) and RLM (radio link monitoring) in MTRP PDCCH transmission

[0231] First, BFD (Beam Failure Detection) should be performed so that the terminal will perform beam failure recovery in a beamformed-based communication environment. In the BFD procedure, the terminal generally determines whether there is a beam failure based on the expected quality of the PDCCH. In other words, the terminal determines whether there is a BF by calculating a hypothetical BLER (Block Error Rate) through a DL RS in a QCL relationship with the PDCCH. NR Release 17 is considering a method of supporting multiple base stations / TRPs / panels / beams participating in PDCCH transmission to improve the reliability or reception quality of the PDCCH. In this case, unlike before, there are multiple DL RSs in a QCL relationship with the PDCCH, so there can be an ambiguity as to how the terminal should perform BFD based on which DL RS. In the present disclosure, a method in which the terminal performs BFD / RLM in such an environment is proposed.

[0232] Hereinafter, the proposal of the present disclosure can be extended and applied to various channels such as PUSCH / PUCCH / PDSCH / PDCCH, etc.

[0233] In Release 16 eNR MIMO, standardization for single-DCI-based PDSCH transmission and multi-DCI-based PDSCH transmission is performed for multi-TRP PDSCH transmission. In Release 17 FeNR MIMO, standardization for multi-TRP transmission excluding PDSCH (e.g., PDCCH, PUCCH, PUSCH, etc.) will be performed (hereinafter, multi-TRP is abbreviated as M-TRP, MTRP, etc.).

[0234] In the present disclosure, " / " means "and" or "or" or "and / or" in context. In the present disclosure, the proposal is mainly described based on PDCCH, but it is not limited thereto, and it can also be applied to channels transmitted by multiple base stations / TRPs / panels / beams together as CoMP (Coordinated Multi-Point) operation.

[0235] As described above, a variety of methods can be considered as methods of multiple base stations / TRPs / panels / beams participating in PDCCH transmission to improve the reliability or reception quality of the PDCCH. For example, a method in which each base station / TRP / panel / beam respectively encodes the same DCI and repeatedly transmits it through different time / frequency / space (antenna port or layer) can be considered. Alternatively, a method in which the same PDCCH is repeatedly transmitted through different time / frequency / space (antenna port or layer) can be considered. Alternatively, a method in which one PDCCH or encoded DCI bits are divided and transmitted through different time / frequency / space (antenna port or layer) can be considered. Alternatively, a variety of methods including a method in which one DCI is divided, respectively encoded, and transmitted through different time / frequency / space (antenna port or layer) can be considered.

[0236] The explanation / determination of whether the base station / TRP / panel / beam is the same or different can be explained / determined by whether the QCL reference RS for each transmission signal is the same or whether the QCL relationship between the QCL reference RSs is established. Finally, the configuration / indication of multiple QCL reference RSs for the same QCL parameter on any unit for PDCCH transmission and reception (e.g., CORESET / search space / CCE / REG / PDCCH occasion, etc.) can be considered a common feature.

[0237] Hereinafter, for convenience of description, it is described under the assumption that multiple QCL reference RSs for the same QCL parameter (not in QCL relationship with) are configured / indicated for a CORESET (or CORESET group), but the method proposed by the present disclosure is not limited thereto and can also be extended and applied to the above-mentioned other PDCCH transmission configuration / indication units (e.g., search space / CCE / REG / PDCCH occasion, etc.).

[0238] In addition, for convenience of description, it is assumed that multiple TCI states defined in the NR system are configured / indicated for the CORESET (or CORESET group) as the "method of configuring / indicating multiple QCL reference RSs for the same QCL parameter".

[0239] There are two methods in which a terminal determines a BFD (Beam Failure Detection) RS (Reference Signal) mainly. In one method, a base station can explicitly configure / indicate a BFD RS. Also, in another method, a terminal determines a BFD RS through PDCCH-related configuration / indication (i.e., implicit determination of a BFD RS). For the latter, a terminal confirms (calculates) a hypothetical BLER with respect to a QCL (Type D) reference RS of each CORESET, and increases a counter of a BFI (Beam Failure Instance) one by one when all hypothetical BLERs are equal to or greater than a threshold value. And, when the BFI counter (number of times) is equal to or greater than a certain value (within a certain period of time), the terminal declares (determines) a BF (Beam Failure) and the terminal initiates transmission of a BFR-PRACH (a version 15 BFR method, i.e., BFR for a SpCell) or a BFR-PUCCH / BFR-MAC-CE (a version 16 BFR method, i.e., BFR for an SCell). Here, when a plurality of QCL (Type D) reference RSs are configured for a certain CORESET (or a CORESET group), a method of determining a BFD RS is not specified. For example, a threshold value related to a hypothetical BLER can be predefined between a base station / TRP, and / or the threshold value can be configured / transmitted to a terminal by a base station / TRP. A method of determining an RLM RS for RLM (Radio Link Monitoring) is similar to BFD, and likewise in this case, as above, when a plurality of QCL (Type D, i.e., QCL configuration / type related to a spatial Rx parameter) reference RSs are configured for a certain CORESET (or a CORESET group), a method of determining an RLM RS is not specified.

[0240] Hereinafter, for the convenience of description, the proposal is described based on BFD, but it is obvious that the same method can be applied to RML likewise.

[0241] Hereinafter, in the present disclosure, when a terminal confirms a hypothetical BLER, it can be interpreted in the same meaning as comparing the hypothetical BLER with a threshold value. Also, in the present disclosure, when a terminal confirms a hypothetical BLER, it can be interpreted in the same meaning as evaluating a radio link quality. Also, as described above, a terminal can perform BFD (i.e., detect a BF) based on a method of evaluating a radio link quality according to the proposal of the present disclosure, and in addition, the method of evaluating a radio link quality according to the proposal of the present disclosure can be used for RLM.

[0242] Proposal 1: When multiple QCL (TypeD) reference RSs are configured for a specific CORESET (or CORESET group) and BFD RS (or RLM RS) is not separately configured through higher layer signaling (e.g., RRC, MAC CE), the terminal confirms hypothetical BLER (i.e., evaluates radio link quality) based on one designated / pre-configured / pre-determined QCL (TypeD) reference RS.

[0243] In other words, the terminal can confirm hypothetical BLER (i.e., evaluate radio link quality) based on a specific QCL (TypeD) reference RS (i.e., RS configured with QCL related to spatial Rx parameter) among multiple QCL (TypeD) reference RSs (i.e., RS configured with QCL related to spatial Rx parameter) for a relevant CORESET for monitoring PDCCH.

[0244] As an example of "one designated / pre-configured / pre-determined QCL (TypeD) reference RS" in the above-described Proposal 1, a QCL (TypeD) reference RS corresponding to a specified / pre-configured / pre-determined specific TCI state among multiple TCI states configured / indicated to the corresponding CORESET can be considered.

[0245] For example, a QCL (TypeD) reference RS corresponding to a first TCI state among multiple TCI states configured / indicated to the corresponding CORESET can be considered. In another example, a QCL (TypeD) reference RS corresponding to a last TCI state among multiple TCI states configured / indicated to the corresponding CORESET can be considered.

[0246] In other words, when multiple TCI states (e.g., TCI state IE) for a specific CORESET are configured, multiple QCL (TypeD) reference RSs can be configured. In other words, each of the multiple TCI states can include information on QCL (TypeD) RS. Here, the multiple TCI states configured for a specific CORESET respectively provide a QCL relationship between a DL RS (i.e., QCL reference RS) in the TCI state and a PDCCH DMRS port.

[0247] In other words, the terminal can confirm hypothetical BLER (i.e., evaluate radio link quality) based on an RS configured as QCL TypeD through a specific TCI state indication / configuration among multiple RSs (i.e., RS configured with QCL related to spatial Rx parameter) configured as QCL TypeD through multiple TCI state indications / configurations for a relevant CORESET for monitoring PDCCH.

[0248] As described above, one or more search spaces can be configured for a terminal. A hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on RS for CORESETs related to all search spaces configured for the terminal. Here, when multiple QCL (TypeD) reference RSs (i.e., RSs for which QCLs related to spatial Rx parameters are configured) are configured for any CORESET, a hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on any one of the QCL (TypeD) reference RSs among them. In one example, when multiple TCI states are configured for any CORESET, a hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on a QCL (TypeD) reference RS (i.e., RS for which QCLs related to spatial Rx parameters are configured) in a specific TCI state among the multiple TCI states. And, when the hypothetical BLERs of all search spaces are equal to or greater than a threshold (i.e., when the radio link quality is worse than the threshold), the physical layer of the terminal can provide an indication (i.e., beam failure instance indication) to a higher layer (e.g., MAC layer).

[0249] In addition, when the hypothetical BLERs of all resources for RLM are equal to or greater than a threshold (i.e., when the radio link quality is worse than the threshold), the physical layer of the terminal can provide an out-of-sync to a higher layer (e.g., MAC layer). Here, when multiple QCL (TypeD) reference RSs are configured, the terminal can use a specific QCL (TypeD) reference RS for RLM as in the proposal.

[0250] An advantage of this proposal is low terminal complexity, but frequent RRC reconfiguration for TCI can occur depending on changes in the TRP (or beam, wireless link) corresponding to the best / worst quality.

[0251] For example, for PDCCH / DCI repetition transmission, if the TRP (or beam, wireless link) corresponding to the specified QCL (TypeD) reference RS is not the best TRP (or beam, wireless link), it can be determined as BF although it can be successfully received by other TRP (or beam, wireless link), so the first TCI state should be changed to the RS corresponding to the best TRP (or beam, wireless link) persistently.

[0252] Proposal 2: When multiple QCL (TypeD) reference RSs are configured for a specific CORESET (or CORESET group) and BFD RS (or RLM RS) is not separately configured through higher layer signaling (e.g., RRC, MAC CE), the terminal confirms a hypothetical BLER (i.e., evaluates radio link quality) based on one QCL (TypeD) reference RS specified / configured by the base station.

[0253] In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., RS configured with QCL related to spatial Rx parameter) designated / configured by the base station among the multiple QCL (TypeD) reference RSs (i.e., RS configured with QCL related to spatial Rx parameter) for the relevant CORESET for monitoring PDCCH.

[0254] In Proposal 2, various signaling methods (e.g., RRC message, MAC-CE message, and / or DCI signaling) can be considered as more specific methods than the "method of designating QCL (TypeD) RS by the base station."

[0255] For example, the order of the TCI state for performing BFD can be designated by the MAC-CE indicating / configuring the TCI state of the CORESET. In other words, among the multiple TCI states for the relevant CORESET for monitoring PDCCH, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., RS configured with QCL related to spatial Rx parameter) indicated / configured in the TCI state designated by the MAC-CE.

[0256] In another example, the terminal performs BFD based on the first TCI state, but an indicator (e.g., an indicator for whether the first TCI state and the second TCI state are exchanged) that can change the order of the multiple TCI states can be introduced by a separate MAC-CE or a MAC-CE indicating / configuring the CORESET TCI state. In other words, the order of the multiple TCI states for the relevant CORESET for monitoring PDCCH can be determined by the indicator that changes the order of the multiple TCI states. And, based on the determined order of the TCI state, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., RS configured with QCL related to spatial Rx parameter) indicated / configured in the first.

[0257] As described above, one or more search spaces can be configured for a terminal. The hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on RS for CORESETs related to all search spaces configured for the terminal. Here, when multiple QCL (TypeD) reference RSs (i.e., RSs for which QCLs related to spatial Rx parameters are configured) are configured for any CORESET, the hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on any one of the QCL (TypeD) reference RSs among them. In one example, when multiple TCI states are configured for any CORESET, the hypothetical BLER (i.e., radio link quality can be evaluated) can be confirmed based on a QCL (TypeD) reference RS (i.e., RS for which QCLs related to spatial Rx parameters are configured) in a specific TCI state among the multiple TCI states. And, when the hypothetical BLERs of all search spaces are equal to or greater than a threshold (i.e., when the radio link quality is worse than the threshold), the physical layer of the terminal can provide an indication (i.e., beam failure instance indication) to a higher layer (e.g., MAC layer).

[0258] In addition, when the hypothetical BLERs of all resources for RLM are equal to or greater than a threshold (i.e., when the radio link quality is worse than the threshold), the physical layer of the terminal can provide out-of-sync to a higher layer (e.g., MAC layer). Here, when multiple QCL (TypeD) reference RSs are configured, the terminal can use a specific QCL (TypeD) reference RS for RLM as in this proposal.

[0259] The advantage of this method is low terminal complexity and the base station can respond more flexibly (or faster) than Proposal 1, because the QCL (TypeD) RS specified by the base station can be changed according to changes in the TRP corresponding to the best / worst TRP (or beam, wireless link) quality. However, the signaling overhead following the base station's QCL (TypeD) RS specification / configuration can increase and the base station can burden continuous quality tracking per TRP.

[0260] Proposal 3: When multiple QCL (TypeD) reference RSs are configured for a specific CORESET (or CORESET group) and BFD RSs (or RLM RSs) are not separately configured through higher layer signaling (e.g., RRC, MAC CE), the terminal confirms the hypothetical BLER (i.e., evaluates the radio link quality) based on the QCL (TypeD) reference RS corresponding to the best quality.

[0261] The method of Proposal 3 is that the terminal determines the QCL (TypeD) reference RS corresponding to the TRP of high quality and selects it as the BFD RS in order to reduce the method in which the base station burdens tracking quality per TRP in Proposal 2 (and Proposal 1).

[0262] For example, the terminal can determine whether the hypothetical BLER of the QCL (TypeD) reference RS corresponding to the lowest hypothetical BLER is equal to or greater than a threshold value. In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., the RS configured with the QCL related to the spatial Rx parameter) corresponding to the lowest hypothetical BLER among the plurality of QCL (TypeD) reference RSs (i.e., the RS configured with the QCL related to the spatial Rx parameter) for the relevant CORESET for monitoring the PDCCH.

[0263] As described above, since a plurality of TCI states (e.g., TCI state IE) of a specific CORESET is configured, a plurality of QCL (TypeD) reference RSs can be configured. In other words, each of the plurality of TCI states can include information on the QCL (TypeD) RS.

[0264] As a result, in the method of the present embodiment, the terminal confirms the hypothetical BLER for all QCL (TypeD) reference RSs, respectively, but it can be considered to be equivalent to a method of determining whether at least one hypothetical BLER is equal to or less than a threshold value (i.e., evaluating the radio link quality).

[0265] In another example, it can be determined whether the hypothetical BLER of the QCL (TypeD) reference RS corresponding to the highest RSRP is equal to or greater than a threshold value. In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., the RS configured with the QCL related to the spatial Rx parameter) corresponding to the highest RSRP among the plurality of QCL (TypeD) reference RSs (i.e., the RS configured with the QCL related to the spatial Rx parameter) for the relevant CORESET for monitoring the PDCCH. This method is a method in which the BF probability prediction is less accurate than the first embodiment, but the complexity of the terminal is reduced by using the RSRP value instead of the BLER estimation.

[0266] To reduce terminal complexity, the QCL (TypeD) RS (corresponding to the lowest BLER / highest RSRP) can not be changed during the BFD duration. In other words, the lowest BLER / highest RSRP value can be changed over time, but it can be fixed to a single QCL (TypeD) RS during the BFD duration. For example, within the BFD duration, it can be determined based on the QCL (TypeD) RS (corresponding to the lowest BLER / highest RSRP) of the first BFI (beam failure indication). This method has the advantage that the base station does not need to perform separate operations according to the change of the best TRP. In addition, this method focuses on avoiding determining it as a BF even if one TRP is normally operating, so it can be more suitable for a case in which the PDCCH / DCI repetition method is applied. However, there is a limitation that the terminal complexity is higher than that of Proposal 1 or 2.

[0267] Proposal 4: When multiple QCL (TypeD) reference RSs are configured for a specific CORESET (or CORESET group) and BFD RSs (or RLM RSs) are not separately configured through higher layer signaling (e.g., RRC, MAC CE), the terminal confirms the hypothetical BLER (i.e., evaluates the radio link quality) based on the QCL (TypeD) reference RS corresponding to the worst quality.

[0268] Proposal 3 focuses on avoiding determining it as a BF even if one TRP is normally operating, but it can not be suitable for the PDCCH / DCI partial transmission because the terminal can normally receive the PDCCH / DCI only when all TRPs are normally operating. Proposal 4 is a method of selecting the BFD RS based on the TRP of the lowest quality in such an environment (e.g., in particular, a DCI partial transmission environment).

[0269] For example, the terminal can determine whether the hypothetical BLER of the QCL (TypeD) reference RS corresponding to the highest hypothetical BLER is equal to or greater than a threshold value. In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., the RS configured with the QCL related to the spatial Rx parameter) corresponding to the highest hypothetical BLER among the multiple QCL (TypeD) reference RSs (i.e., the RS configured with the QCL related to the spatial Rx parameter) of the relevant CORESET for monitoring the PDCCH. As a result, in this method, the hypothetical BLER of all QCL (TypeD) reference RSs is confirmed respectively, but it can be considered to be equivalent to a method of determining whether all hypothetical BLERs are equal to or less than a threshold value.

[0270] In another example, the terminal can determine whether the hypothetical BLER of the QCL (TypeD) reference RS corresponding to the lowest RSRP is equal to or greater than a threshold value. In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) based on the QCL (TypeD) reference RS (i.e., the RS configured with the QCL related to the spatial Rx parameter) corresponding to the RSRP among the plurality of QCL (TypeD) reference RSs (i.e., the RS configured with the QCL related to the spatial Rx parameter) for monitoring the related CORESET of the PDCCH. This method is a method in which the BF probability prediction is less accurate than the first embodiment, but the complexity of the terminal is reduced by using the RSRP value instead of the BLER estimation.

[0271] (In the above two embodiments) To reduce the complexity of the terminal, the QCL (TypeD) RS (corresponding to the highest BLER / lowest RSRP) can not be changed during the BFD duration. In other words, the lowest BLER / highest RSRP value can change over time, but it can be fixed to a single QCL (TypeD) RS during the BFD duration. For example, during the BFD duration, it can be determined based on the QCL (TypeD) RS (corresponding to the highest BLER / lowest RSRP) of the first BFI (beam failure indication). This method has the advantage that the base station does not need to perform a separate operation according to the change of the worst TRP. However, like Proposal 3, there is a limitation that the complexity of the terminal is higher than that of Proposal 1 or 2.

[0272] Proposal 5: When multiple QCL (TypeD) reference RSs are configured for a specific CORESET (or CORESET group) and the BFD RS (or RLM RS) is not separately configured through higher layer signaling (e.g., RRC, MAC CE), the terminal calculates and confirms (combines / compounds) the hypothetical BLER (i.e., evaluates the radio link quality) by using the multiple corresponding QCL (TypeD) reference RSs.

[0273] Proposal 3 focuses on avoiding determining BF even if one TRP is normally operating, but it can not be suitable for PDCCH / DCI partial transmission because the terminal normally receives the PDCCH / DCI only when all TRPs are normally operating. Proposal 4 is a method of determining the BFD RS based on the lowest quality TRP in such an environment (e.g., especially a DCI partial transmission environment). For PDCCH partial transmission, it is more accurate to confirm the BLER by considering all QCL (TypeD) reference RSs if the TRPs divide and transmit the coded bits, so Proposal 5 is proposed.

[0274] In other words, the terminal can confirm the hypothetical BLER (i.e., evaluate the radio link quality) by fully using the multiple QCL (Type-D) reference RSs (i.e., RSs configured with QCL related to spatial Rx parameters) for monitoring the related CORESET of the PDCCH.

[0275] For example, the terminal can combine each power of each RS to calculate (derive) the signal power, combine all remaining power excluding the RS power from the RE (Resource Element) power of each RS to calculate (derive) the interference plus noise power, and calculate the SINR and the hypothetical BLER based on it.

[0276] In another example, the terminal can calculate (derive) the signal power by the (weighted) average of the power of each RS, calculate (derive) the interference plus noise power by the (weighted) average of the remaining power excluding the RS power from the RE power of each RS, and calculate the SINR and the hypothetical BLER based on it.

[0277] This method also has the advantage that the base station does not need to perform separate operations according to the quality change of the TRP, but like proposals 3 and 4, there is a limitation that the terminal complexity is higher than proposals 1 and 2.

[0278] When applying these proposals (e.g., proposals 1 / 2 / 3 / 4 / 5, etc.), different proposals can be applied according to the separate configuration of the base station or the MTRP transmission method for PDCCH / DCI. For example, it can be specified / configured that proposal 3 is applied for PDCCH / DCI repetition transmission, proposal 4 is applied for DCI partial transmission, and proposal 5 is applied for PDCCH partial transmission.

[0279] Among these proposals, various methods for the terminal to perform BFD RS determination and hypothetical BLER calculation when multiple QCL (Type-D) reference RSs are configured / indicated to one CORESET (or CORESET group) are proposed.

[0280] If multiple CORESETs are configured for one or more component carriers (CCs) / bandwidth parts (BWPs) configured for the terminal, the process of selecting a BFD RS (or RLM RS) for multiple CORESETs can be additionally performed after applying the proposals per CORESET.

[0281] For example, assume a case where M (M is a natural number) CORESETs (with different TCIs) are configured (across a certain CC / BWP or multiple CCs / BWPs). In this case, the terminal can be designated / configured to select (up to) N (N≤M, N is a natural number) CORESETs by considering the computational complexity of the terminal to perform BFD (or RLM) only for the QCL (TypeD) RS of the corresponding CORESET.

[0282] Here, N can be a designated value (e.g., N=2 for each CC / BWP) or a value configured by the base station. Alternatively, the value of N can be designated / configured differently according to the BFD (RS selection) method for each CORESET (or CORESET group). For example, when applying Proposal 3 / 4 / 5, the terminal can calculate the hypothetical BLER or RSRP for multiple RSs, which increases the computational complexity compared to the case where there is one QCL (TypeD) RS, so it can be configured to apply N=1 per CC / BWP. On the other hand, when applying proposed techniques 1 / 2 or when there is only one CORESET TCI as before, N=2 can be configured to be applied per CC / BWP.

[0283] Here, the terminal can report the maximum applicable value of N to the base station in the form of capability. In particular, the terminal can report the value of N for the case where multiple TCIs are configured for a CORESET (or CORESET group) to the base station as a separate UE capability. In addition, the terminal can report the value of N to be applied according to the BFD (RS selection) method for the CORESET (or CORESET group) (i.e., the method applied among Proposal 1 to Proposal 5) to the base station as a separate UE capability. For example, the terminal can separately report the value of N to be applied when applying Proposal 1 / 2 and the value of N to be applied when applying Proposal 3 / 4 / 5 to the base station, respectively.

[0284] As described above, when multiple QCL (Type-D) reference RSs are configured for a specific CORESET (or CORESET group), the above proposals (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.) can be applied through an RLM RS determination method for RLM (Radio Link Monitoring). In other words, the proposals of the present disclosure (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.) can also be applied when determining an RLM RS and calculating a related hypothetical BLER. In this case, the value of N (i.e., the number of CORESETs for RLM) to be applied can also be defined / configured separately from the value of N (i.e., the number of CORESETs for BFD) for BFD. In addition, for the value of N to be applied, as described above, the terminal can report the value of N for the case where multiple TCIs are configured for a CORESET to the base station as a UE capability. Alternatively, because the value of N applied according to the BFD (RS selection) method for a CORESET (or CORESET group) (i.e., a method applied among Proposal 1 to Proposal 5) can be changed, the terminal can report a separate N value to the base station according to the applied method.

[0285] Figure 8 A signaling method illustrating a method for evaluating radio link quality according to an embodiment of the present disclosure.

[0286] Figure 8 Signaling between a UE and a network (e.g., TRP 1, TRP 2) in a case where multiple TRPs (i.e., M-TRP or multiple cells, hereinafter, all TRPs can be replaced with cells) to which the methods proposed in the present disclosure (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.) can be applied is illustrated. Figure 8 This is merely for the convenience of description, and it does not limit the scope of the present disclosure. In addition, some steps illustrated in the above Figure 8 in FIG. 1.

[0287] Reference Figure 8, for convenience of description, signaling between 2 TRPs and a UE is illustrated, but a corresponding signaling method can be extended and applied to signaling between multiple TRPs and multiple UEs. In the following description, a network can be one base station including multiple TRPs or can be one cell including multiple TRPs. In an example, ideal backhaul / non-ideal backhaul can be configured between TRP 1 and TRP 2 configuring the network. In addition, the following description is described based on multiple TRPs, but it can be equally extended and applied to transmission through multiple panels. In addition, in the present disclosure, the operation of the terminal receiving a signal from TRP 1 / TRP 2 can be interpreted / described as the operation of the terminal receiving a signal from the network (or can be such an operation) through / using TRP 1 / 2, and the operation of the terminal transmitting a signal to TRP 1 / TRP 2 can be interpreted / described as the operation of the terminal transmitting a signal to the network (or can be such an operation) through / using TRP 1 / TRP 2 or can be interpreted / described in the opposite direction.

[0288] Referring to Figure 8 , it is assumed that a UE receives configuration / DCI from a representative TRP (e.g., TRP 1) in an M-TRP (or cell, hereinafter, all TRPs can be replaced with a cell / panel, or a case where multiple CORESETs are configured from one TRP can be assumed as an M-TRP) situation. This is merely for convenience of description, and the following method can be extended and applied even when the UE receives configuration / DCI from at least one TRP. In an example, the representative TRP can be a TRP that delivers / transmits a signal related to a system information block (SIB) / paging / random access (RA) to the UE.

[0289] The UE can receive configuration information related to M-TRP-based transmission and reception from the network through / using TRP 1 (and / or TRP 2) (S801). The configuration information can include information related to configuration (e.g., TRP configuration) of the network / M-TRP-based transmission and reception (e.g., resource allocation, etc.), etc. In this case, the configuration information can be transmitted through higher layer signaling (e.g., RRC signaling, MAC-CE, etc.).

[0290] For example, the configuration information may include configuration information related to the BFD process and / or the BFR process described in the above proposals (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.). In an example, the configuration information may include information about a CORESET / COREST group associated with each TRP (e.g., TCI state configuration / CORESET group identifier (ID) associated with the CORESET group, etc.). In an example, the configuration information may include information for selecting / configuring a portion of a plurality of CORESETs ( / CORESET groups) (e.g., the number of portions). In an example, the configuration information may include information about a BFD RS / BFD RS set associated with the BFD process, and, depending on the situation, may not explicitly configure / indicate the BFD RS / BFD RS set. In an example, the configuration information may include information about a plurality of RSs (reference signals) (i.e., RSs configured with QCL related to spatial Rx parameters or QCL type D RSs) configured for a spatial relationship assumption (e.g., QCL relationship) configured for a specific CORESET ( / CORESET group). In an example, the configuration information may include configuration information about BFRQ resources associated with the BFR process. In an example, the configuration information may include a CORESET configuration.

[0291] For example, the UE performs the following steps in step S801 ( Figure 11 100 / 200) from the network ( Figure 11 The operation of receiving the configuration information in 100 / 200) can be performed by the following method. Figure 11 For example, refer to Figure 11 The one or more processors 102 may control the one or more transceivers 106 and / or the one or more memories 104 to receive configuration information, and the one or more transceivers 106 may receive configuration information from the network.

[0292] The UE may receive BFD / BFR related information from the network via MAC-CE and / or DCI through / using TRP 1 (and / or TRP 2) (S802). For example, as in the above-mentioned proposals (e.g., Proposals 1 / 2 / 3 / 4 / 5, etc.), the UE may receive information related to the BFD process and / or the BFR process through MAC-CE signaling and / or DCI. For example, as described in Proposal 2, information indicating / configuring an RS to be used as a BFD RS among multiple RSs (reference signals) used for a spatial relationship assumption (e.g., QCL relationship) (i.e., RSs configured with QCL related to spatial Rx parameters or QCL type D RSs) may be received through MAC-CE and / or DCI.

[0293] For example, the UE performs the following steps in step S802 ( Figure 11100 / 200) from the network ( Figure 11 The operation of receiving BFD / BFR related information by 100 / 200) can be performed by the following method. Figure 11 For example, refer to Figure 11 The one or more processors 102 may control the one or more transceivers 106 and / or the one or more memories 104 to receive BFD / BFR related information, and the one or more transceivers 106 may receive BFD / BFR related information from the network.

[0294] The UE may perform a BFD procedure with the network (via / using TRP 1 and / or TRP 2) S803. For example, the UE may perform the BFD procedure based on the above proposals (e.g., proposals 1 / 2 / 3 / 4 / 5, etc.). For example, the UE may perform the BFD procedure based on the BFD RS. For example, as described in the above proposals (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.), when multiple QCL (Type D) reference RSs are configured for a specific CORESET (or CORESET group) and the BFD RSs are not separately configured through higher layer signaling (e.g., the above configuration information), the UE can perform the BFD process based on / by using one of the following: i) one predefined QCL (Type D) RS, ii) the QCL (Type D) RS configured by the base station / TRP, iii) the QCL (Type D) RS corresponding to the best quality (e.g., the lowest hypothetical BLER / highest RSRP, etc.), iv) the QCL (Type D) RS corresponding to the worst quality (e.g., the highest hypothetical BLER / lowest RSRP), and v) multiple QCL (Type D) RSs (i.e., one of i) to v)).

[0295] For example, when multiple CORESETs ( / CORESET groups) are configured, the BFD process can be performed in some of them. For example, when the hypothetical BLER is equal to or greater than the threshold of the BFD RS (e.g., QCL (Type D) reference RS) (i.e., when the radio link quality is worse than the threshold), the terminal increases the counter of the BFI (beam failure instance) one by one. And, when the BFI counter (within a certain period of time) becomes equal to or greater than a specific value, the terminal can declare BF (beam failure) and initiate transmission of BFR-PRACH (Release 15 BFR method, i.e., BFR for SpCell) or BFR-PUCCH / BFR-MAC-CE (Release 16 BFR method, i.e., BFR for SCell).

[0296] For example, the UE performs the following steps in step S803 ( Figure 11 100 / 200) and the network ( Figure 11the operations of the BFD procedure in 100 / 200 can be implemented by the devices to be 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, etc., to perform the BFD procedure, and the one or more transceivers 106 can perform transmission and reception related to the BFD procedure with the network.

[0297] The UE can perform the BFR procedure with the network (through / using the TRP 1 and / or the TRP 2) (S804). For example, the UE can perform the BFR procedure based on the above proposals (e.g., Proposal 1 / 2 / 3 / 4 / 5, etc.).

[0298] For example, the UE performs the BFR procedure with the network (through / using the TRP 1 and / or the TRP 2) in 100 / 200 of the above step S804 Figure 11 Figure 11 The operations of the BFR procedure in 100 / 200 can be implemented by the devices to be 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, etc., to perform the BFR procedure, and the one or more transceivers 106 can perform transmission and reception related to the BFR procedure with the network.

[0299] As described above, the above network / UE signaling and operations (e.g., Proposal 1 / Proposal 2 / Proposal 3 / Proposal 4 / Proposal 5 / Figure 11 , etc.) can be implemented by the devices to be described below (e.g., Figure 8 For example, the network (e.g., the TRP 1 / TRP 2) can correspond to a first wireless device and the UE can correspond to a second wireless device, and in some cases, the reverse case can be considered.

[0300] For example, the above network / UE signaling and operations (e.g., Proposal 1 / Proposal 2 / Proposal 3 / Proposal 4 / Proposal 5 / Figure 11 , etc.) can be processed by one or more processors (e.g., 102, 202) in Figure 8 The above network / UE signaling and operations (e.g., Proposal 1 / Proposal 2 / Proposal 3 / Proposal 4 / Proposal 5 / Figure 11 , etc.) can be stored in a memory (e.g., one or more memories (e.g., 104, 204) in Figure 8 in the form of commands / programs (e.g., instructions, executable code) for operating at least one processor (e.g., 102, 202). Figure 11

[0301] Figure 11 ​​is a diagram illustrating operations of a method for evaluating radio link quality of a terminal according to an embodiment of the present disclosure.

[0302] Figure 9 The diagram shows the operation of the terminal based on Proposals 1 to 5. Figure 9 The examples in are for the convenience of description and do not limit the scope of the present disclosure. Figure 9 In addition, Figure 9 The terminals are examples only and can be represented by Figure 9 For example, Figure 11 The processor 102 / 202 may control the transmission and reception of channels / signals / data / information, etc. by using the transceiver 106 / 206 and may also control the storage of channels / signals / data / information, etc. to be transmitted or received in the memory 104 / 204.

[0303] in addition, Figure 11 The operations in Figure 9 One or more processors 102 and 202 process and Figure 11 The operations in can be used to operate Figure 9 The instructions / program (eg, instructions, executable code) of at least one processor (eg, 102, 202) are stored in a memory (eg, Figure 11 in one or more memories (104, 204)).

[0304] refer to Figure 11 , the terminal can send UE capability information to the base station (S901).

[0305] As described above, M (M is a natural number) CORESETs (or CORESET groups) are configured for the terminal and radio link quality can be evaluated based on RSs of N (N ≤ M, N is a natural number) CORESETs (or CORESET groups) among the M CORESETs. In this case, the UE capability information can include a maximum value of N that can be supported by the terminal. In addition, the value of N can be a value determined or configured in advance by the base station. In this case, step S901 can be omitted. In addition, when M (M is a natural number) CORESETs are configured for the terminal, radio link quality can be evaluated based on RSs of all M CORESETs, and in this case, step S901 can be omitted. In addition, as described above, when a plurality of TCI states are configured for a plurality of CORESETs (or CORESET groups), a maximum value of N that can be supported by the terminal can be reported to the base station as separate UE capability information. Alternatively, a value of N to be applied according to a BFD (RS selection) method for a CORESET (or CORESET group) can be reported to the base station as separate UE capability.

[0306] The terminal receives configuration information related to a CORESET (control resource set) from the base station (S902).

[0307] Here, the configuration information can include information on one or more reference signals configured per CORESET. Here, the reference signal can include a QCL (Type D) reference RS (i.e., an RS for which QCL related to spatial Rx parameters is configured). In addition, for example, the configuration information can include one or more TCI state information configured per CORESET. Also, each TCI state can include information on one or more reference signals. Here, the reference signal can include a QCL (Type D) reference RS (i.e., an RS for which QCL related to spatial Rx parameters is configured).

[0308] As described above, one or more search spaces can be configured for the terminal, and a CORESET ID can be configured per search space. In this case, the configuration information can include information on a CORESET identified by a CORESET ID related to each search space.

[0309] The terminal evaluates radio link quality based on one or more reference signals (RSs) for a CORESET related to a PDCCH monitored by the terminal (S903).

[0310] Here, evaluating radio link quality can mean comparing a hypothetical BLER (or SINR, RSRP) with a threshold as described above.

[0311] In addition, the radio link quality may be evaluated based on one or more reference signals among a plurality of reference signals configured with QCL (quasi co-location) related to the spatial Rx parameters for CORESET (ie, QCL type D).

[0312] Here, according to Proposal 1, the terminal can evaluate the radio link quality based on one reference signal selected according to a predetermined rule from among multiple reference signals for the CORESET. When multiple TCI states for the CORESET are configured and multiple reference signals are configured in each of the multiple TCI states, one reference signal can be determined based on the TCI state selected according to the predetermined rule from among the multiple TCI states.

[0313] In addition, according to Proposal 2, the radio link quality can be evaluated based on one reference signal configured by the base station among multiple reference signals for the CORESET. When multiple TCI states are configured for the CORESET and multiple reference signals are configured for each of the multiple TCI states, one reference signal can be determined by a specific (e.g., first) TCI state among the multiple TCI states. Here, the order of the multiple TCI states can be configured by the base station. In addition, the base station can configure which TCI state among the multiple TCI states determines the one reference signal.

[0314] In addition, according to Proposal 3, the radio link quality may be evaluated based on one reference signal with the best quality among multiple reference signals for CORESET. Here, the reference signal with the best quality may be a reference signal with the lowest hypothetical BLER or the highest RSRP.

[0315] In addition, according to Proposal 4, the radio link quality may be evaluated based on one reference signal with the worst quality among multiple reference signals for CORESET. Here, the reference signal with the worst quality may be a reference signal with the highest hypothetical BLER or the lowest RSRP.

[0316] In addition, according to Proposal 5, the radio link quality can be evaluated based on all of the multiple reference signals for the CORESET. Here, the signal strength can be derived by combining the strengths of the multiple reference signals for the CORESET, the interference and noise strength can be derived by combining the strengths excluding the strength of each of the multiple reference signals from the strength of each RE of the multiple reference signals for the CORESET, and the radio link quality can be evaluated based on the signal strength and the interference and noise strength. Alternatively, the signal strength can be derived by performing a weighted average on the strengths of the multiple reference signals for the CORESET, the interference and noise strength can be derived by performing a weighted average on the strengths excluding the strength of each of the multiple reference signals from the strength of each RE of the multiple reference signals for the CORESET, and the radio link quality can be evaluated based on the signal strength and the interference and noise strength.

[0317] In addition, the radio link quality can be evaluated based on a reference signal for each of a plurality of reference signals for the CORESET. In this case, the radio link quality can be evaluated based on each hypothetical BLER using each reference signal.

[0318] The terminal can use this method to evaluate the radio link quality and use (based on) such an evaluation to perform BFD or RLM operations. For example, when the terminal that evaluates the radio link quality using this method claims a beam failure, the terminal can send a BFRQ (Beam Failure Recovery Request) message to the base station. And, the base station that receives the BFRQ can perform beam recovery through various processes such as beam RS transmission for beam recovery, beam report request, etc. Alternatively, for RLM, when the terminal that evaluates the radio link quality using this method determines that it is out of synchronization, the terminal can perform operations such as RRC connection reestablishment, handover, cell reselection, cell measurement, etc.

[0319] Figure 9 is a diagram illustrating operations of a base station for supporting radio link quality evaluation according to an embodiment of the present disclosure.

[0320] refer to Figure 10 , Figure 10 The diagram shows the operations of the base station based on Proposals 1 to 5. Figure 10 The examples are for illustrative purposes only and do not limit the scope of the present invention. Figure 10 Some steps illustrated in FIG can be omitted according to circumstances and / or configurations. Figure 10 The base station is just an example. Figure 10 For example, Figure 11The processor 102 / 202 in the electronic device can control transmission and reception of a channel / signal / data / information, etc. by using the transceiver 106 / 206, and can control to store the channel / signal / data / information, etc. to be transmitted or received in the memory 104 / 204.

[0321] Further, Figure 11 The operations in the electronic device can be processed by Figure 10 one or more processors 102 and 202 in the electronic device and Figure 11 The operations in the electronic device can be stored in the form of commands / programs (e.g., instructions, executable codes) for operating Figure 11 at least one processor (e.g., 102, 202) in the memory (e.g., Figure 10 one or more memories (104, 204) in the electronic device.

[0322] Referring to Figure 11 , the base station can receive UE capability information from the terminal (S1001).

[0323] As described above, M (M is a natural number) CORESETs (or CORESET groups) are configured for the terminal, and radio link quality can be evaluated based on RSs of N (N≤M, N is a natural number) CORESETs (or CORESET groups) among the M CORESETs. In this case, the UE capability information can include a value of N that the terminal can support. In addition, the value of N can be a value determined or configured by the base station in advance. In this case, step S1001 can be omitted. In addition, when M (M is a natural number) CORESETs are configured for the terminal, radio link quality can be evaluated based on RSs of all M CORESETs, and in this case, step S1001 can be omitted. In addition, as described above, when a plurality of TCI is configured for a plurality of CORESETs (or CORESET groups), a maximum value of N that the terminal can support can be reported to the base station as separate UE capability information. Alternatively, a value of N applied to a CORESET (or CORESET group) according to a BFD (RS selection) method can be reported to the base station as separate UE capability.

[0324] The base station transmits configuration information related to a CORESET (control resource set) to the terminal (S1002).

[0325] Here, the configuration information can include information on one or more reference signals configured per CORESET. Here, the reference signal can include a QCL (Type D) reference RS (i.e., an RS for which QCL related to spatial Rx parameters is configured). In addition, for example, the configuration information can include one or more TCI state information configured per CORESET. Also, each TCI state can include information on one or more reference signals. Here, the reference signal can include a QCL (Type D) reference RS (i.e., an RS for which QCL related to spatial Rx parameters is configured).

[0326] As described above, one or more search spaces can be configured for the terminal, and a CORESET ID can be configured per search space. In this case, the configuration information can include information on a CORESET identified by a CORESET ID related to each search space.

[0327] Subsequently, the terminal evaluates the radio link quality based on one or more reference signals (RSs) for a CORESET related to a PDCCH to be monitored by the terminal according to the proposal. Here, evaluating the radio link quality can mean comparing a hypothetical BLER (or SINR, RSRP) with a threshold as described above. In addition, the radio link quality can be evaluated based on one or more reference signals among a plurality of reference signals for which QCL (Quasi Co-Location) related to spatial Rx parameters for the CORESET is configured (i.e., QCL Type D).

[0328] Here, according to Proposal 1, the terminal can evaluate the radio link quality based on one reference signal selected from among a plurality of reference signals for the CORESET according to a predetermined rule. When a plurality of TCI states for the CORESET is configured and each of the plurality of TCI states is configured with a plurality of reference signals, one reference signal can be determined according to a TCI state selected from among the plurality of TCIs according to the predetermined rule.

[0329] In addition, according to Proposal 2, the radio link quality can be evaluated based on one reference signal among a plurality of reference signals for the CORESET configured by the base station. When a plurality of TCI states for the CORESET is configured and a plurality of reference signals is configured by each of the plurality of TCI states, one reference signal can be determined by a specific (e.g., first) TCI state among the plurality of TCI states. Here, the order of the plurality of TCI states can be configured by the base station. In addition, which TCI state among the plurality of TCI states determines one reference signal can be configured by the base station.

[0330] In addition, according to Proposal 3, the radio link quality can be evaluated based on one reference signal having the best quality among the plurality of reference signals for the CORESET. Here, the reference signal having the best quality can be the reference signal having the lowest hypothetical BLER or the highest RSRP.

[0331] In addition, according to Proposal 4, the radio link quality can be evaluated based on one reference signal having the worst quality among the plurality of reference signals for the CORESET. Here, the reference signal having the worst quality can be the reference signal having the highest hypothetical BLER or the lowest RSRP.

[0332] In addition, according to Proposal 5, the radio link quality can be evaluated based on all of the plurality of reference signals for the CORESET. Here, the signal strength can be derived by combining the strengths of the plurality of reference signals for the CORESET, the interference and noise strength can be derived by combining the strengths excluding the strength of each of the plurality of reference signals from the strength of each RE of the plurality of reference signals for the CORESET, and the radio link quality can be evaluated based on the signal strength and the interference and noise strength. Alternatively, the signal strength can be derived by performing a weighted average on the strengths of the plurality of reference signals for the CORESET, the interference and noise strength can be derived by performing a weighted average on the strengths excluding the strength of each of the plurality of reference signals from the strength of each RE of the plurality of reference signals for the CORESET, and the radio link quality can be evaluated based on the signal strength and the interference and noise strength.

[0333] In addition, the radio link quality can be evaluated based on each of the plurality of reference signals for the CORESET. In this case, the radio link quality can be evaluated based on each hypothetical BLER through each reference signal.

[0334] When a terminal that evaluates the radio link quality by using this method declares a beam failure, the base station can receive a BFRQ (Beam Failure Recovery Request) message from the terminal. Also, the base station that receives the BFRQ can perform a beam recovery through various procedures such as a beam RS transmission, a beam report request, etc. to perform a beam recovery. In other words, the base station can perform a BFR. Alternatively, for RLM, when a terminal that evaluates the radio link quality by using this method determines that it is out of synchronization, the terminal can perform an operation such as an RRC connection reestablishment, a handover, a cell reselection, a cell measurement, etc. and the base station can perform a related operation according to the procedure determined by the terminal.

[0335] General purpose device to which the present disclosure can be applied

[0336] Figure 11FIG. 1 is a diagram illustrating a block diagram of a wireless communication device according to an embodiment of the disclosure.

[0337] Referring to Figure 11 The first wireless device 100 and the second wireless device 200 can transmit and receive wireless signals through various radio access technologies (e.g., LTE, NR).

[0338] The first wireless 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 disclosure. For example, the processor 102 can transmit, after generating first information / signal by processing information in the memory 104, a wireless signal including the first information / signal through the transceiver 106. Also, the processor 102 can receive, through the transceiver 106, a wireless signal including second information / signal, 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 various information related to the operation of the processor 102. For example, the memory 104 can store software code including commands for executing all or part of processes controlled by the processor 102 or for executing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the disclosure. Here, the processor 102 and the memory 104 can be a part of a communication modem / circuit / 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 wireless signals 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 disclosure, a wireless device can mean a communication modem / circuit / chip.

[0339] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then transmit a wireless signal including the third information / signals through the transceiver 206. In addition, the processor 202 may receive a wireless signal including fourth information / signals through the transceiver 206, and then store information obtained by signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including commands for executing all or part of the processes controlled by the processor 202 or for executing the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In this disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0340] Hereinafter, the hardware elements of the wireless devices 100, 200 will be described in more detail. They are not limited thereto, and one or more protocol layers can be implemented by the one or more processors 102, 202. For example, the one or more processors 102, 202 can implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). The 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. The 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. The one or more processors 102, 202 can generate signals (e.g., baseband signals) including the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure to provide the same to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure.

[0341] 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, and the like. 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.

[0342] The one or more memories 104, 204 may be connected to the one or more processors 102, 202 and may store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. The one or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, a hard drive, registers, cash memory, a computer-readable storage medium, and / or a combination thereof. The one or more memories 104, 204 may be located internally and / or externally to the one or more processors 102, 202. Furthermore, the one or more memories 104, 204 may be connected to the one or more processors 102, 202 via a variety of technologies, such as wired or wireless connections.

[0343] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, and the like mentioned in the methods and / or operational flowcharts, etc., disclosed herein to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, and the like mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc., disclosed herein from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. 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 description, functions, processes, proposals, methods and / or operational flowcharts of the present disclosure through one or more antennas 108, 208. In the present invention, one or more antennas can be multiple physical antennas or multiple 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 using one or more processors 102, 202 to process received user data, control information, wireless signals / channels, etc. 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. Therefore, one or more transceivers 106, 206 can include (analog) oscillators and / or filters.

[0344] The above-described embodiments of the present disclosure are combinations of elements and features of the present disclosure. Unless otherwise mentioned, each element or feature of the present disclosure should be considered optional. Each element or feature of the present disclosure can be implemented in a form not to be combined with other elements or features. Further, embodiments of the present disclosure can include a combination of one or more elements 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 another embodiment or can replace an corresponding element or feature in another embodiment. It is apparent that claims that are not explicitly dependent on each other can be combined in the implementation of embodiments of the present disclosure. It is further apparent that embodiments can be included through modification of the existing claims by the application based on the claims depending on each other, as the scope of the claims of the present disclosure should be determined not by the application but by the claims and their equivalents.

[0345] It will be 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 construed in a limiting sense as to the scope of the present disclosure, but should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims and all changes within the equivalent scope of the present disclosure are included in the scope of the present invention.

[0346] 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 storage media or computer-readable storage media, and the features described in the present disclosure can be implemented by using a computer program product including such storage media. The storage media can include a high-speed random access memory such as a DRAM, SRAM, DDR RAM, or other random access solid state storage device, 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 device in the memory includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any one of machine-readable media 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 with results from the 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.

[0347] 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.

[0348] Industrial applicability

[0349] 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 evaluating radio link quality in a wireless communication system, the method performed by a terminal comprising: receiving configuration information associated with one or more control resource sets (CORESETs) from a base station; determining one or more reference signals for the one or more CORESETs associated with a physical downlink control channel (PDCCH) to evaluate radio link quality based on that a specific reference signal for beam failure detection is not configured for the terminal; as well as evaluating the radio link quality based on the one or more reference signals, Wherein, based on configuring multiple transmission configuration indication (TCI) states for a CORESET among the one or more CORESETs by the configuration information, multiple reference signals associated with the multiple TCI states of the CORESET are used to evaluate the radio link quality.

2. The method according to claim 1, wherein The radio link quality is evaluated based on each of the plurality of reference signals for the CORESET.

3. The method according to claim 2, wherein: The radio link quality is evaluated based on each hypothetical block error rate (BLER) calculated from each of the plurality of reference signals.

4. The method according to claim 1, wherein The radio link quality is evaluated based on all the plurality of reference signals for the CORESET.

5. The method according to claim 4, wherein deriving a signal strength by combining the strengths of the plurality of reference signals for the CORESET, wherein the interference and noise strengths are derived by combining the strengths excluding the strength of each reference signal of the plurality of reference signals from the strength of each resource element of the plurality of reference signals for the CORESET, The radio link quality is evaluated based on the signal strength and the interference and noise strengths.

6. The method according to claim 4, wherein: deriving a signal strength by performing a weighted average of the strengths of the plurality of reference signals for the CORESET, wherein the interference and noise strength is derived by performing a weighted average on a strength excluding a strength of each reference signal of the plurality of reference signals from a strength of each resource element of the plurality of reference signals for the CORESET, The radio link quality is evaluated based on the signal strength and the interference and noise strengths.

7. The method according to claim 1, wherein Configure M CORESETs for the terminal, where M is a natural number. The radio link quality is evaluated based on RSs for N CORESETs among the M CORESETs, where N≤M, and N is a natural number.

8. The method according to claim 7, wherein: The value of N is a value predetermined or configured by the base station.

9. The method according to claim 7, further comprising: UE capability information including a maximum value of N that the terminal can support is sent to the base station.

10. The method according to claim 1, wherein Based on the evaluation of the radio link quality, a beam failure detection (BFD) or radio link monitoring (RLM) operation is performed.

11. A terminal for evaluating radio link quality in a wireless communication system, the terminal comprising: one or more transceivers for transmitting and receiving wireless signals; and one or more processors, the one or more processors controlling the one or more transceivers; wherein the one or more processors are configured to: receiving configuration information associated with one or more control resource sets (CORESETs) from a base station; determining one or more reference signals for the one or more CORESETs related to a physical downlink control channel (PDCCH) to evaluate radio link quality based on that a specific reference signal for beam failure detection is not configured for the terminal; and evaluating the radio link quality based on the one or more reference signals, Wherein, based on configuring multiple transmission configuration indication (TCI) states for a CORESET among the one or more CORESETs by the configuration information, multiple reference signals associated with the multiple TCI states of the CORESET are used to evaluate the radio link quality.

12. A method for supporting evaluation of radio link quality by a terminal in a wireless communication system, the method performed by a base station comprising: Sending configuration information related to one or more control resource sets (CORESETs) to the terminal; wherein, based on the fact that a specific reference signal for beam failure detection is not configured for the terminal, one or more reference signals for the one or more CORESETs related to a physical downlink control channel (PDCCH) among the multiple reference signals are determined for the terminal to evaluate radio link quality; and wherein, based on configuring a plurality of transmission configuration indication (TCI) states for a CORESET among the one or more CORESETs by the configuration information, a plurality of reference signals associated with the plurality of TCI states of the CORESET are used to evaluate the radio link quality; and Based on evaluating the radio link quality, an uplink channel for beam failure recovery is received from the terminal.

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