Method and device for performing beam recovery in wireless communication system

Abstract

The present invention relates to a method and apparatus for performing beam restoration in a wireless communication system. This specification provides a method for restoring a beam in a wireless communication system. In this specification, the method for restoring a beam by a terminal may include: receiving a beam reference signal (BRS) from a base station to be used for beam management; when a beam failure event is detected based on the received BRS, transmitting a control signal for a beam restoration request to the base station; and when a beam report is triggered, reporting beam measurement results to the base station in specific resources.

Description

[0001] This application is a divisional application of a patent application filed on October 9, 2019, with an application date of August 21, 2017, application number 201780089430.7 (PCT / KR2017 / 009084), and invention name “Method and device for performing beam recovery in a wireless communication system”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is a national phase filing of International Application No. PCT / KR2017 / 009084, filed on August 21, 2017, under 35 U.S.C. §371, claiming the benefit of U.S. Provisional Application No. 62 / 469,507, filed on March 9, 2017, the entire contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] The present disclosure relates to a wireless communication system, and more particularly, to a method for performing beam recovery and a device supporting the method. Background Art

[0005] Mobile communication systems are typically developed to provide voice services while ensuring user mobility. These mobile communication systems have gradually expanded their coverage from voice services to data services, and ultimately to high-speed data services. However, as current mobile communication systems suffer from resource shortages and users demand even higher-speed services, there is a need to develop more advanced mobile communication systems.

[0006] The requirements for next-generation mobile communication systems may include supporting huge data traffic, significantly increasing the transmission rate per user, accommodating a significant increase in the number of connected devices, very low end-to-end latency, and high energy efficiency. To this end, various technologies such as small cell enhancement, dual connectivity, massive multiple-input multiple-output (MIMO), in-band full-duplex, non-orthogonal multiple access (NOMA), support for ultra-wideband, and device networking are being studied. Summary of the Invention

[0007] Technical issues

[0008] This specification will provide a method for performing beam restoration by sending a beam restoration request message when a beam failure event occurs due to movement of a UE or the like.

[0009] In addition, the present specification will provide a method for notifying the eNB whether a replacement beam exists, and thereby triggering the aperiodic beam RS and / or aperiodic beam report by the eNB.

[0010] The technical objectives to be achieved in the present disclosure are not limited to the above-mentioned technical objectives, and a person skilled in the art in the art to which the present disclosure belongs can obviously understand other technical objectives not described above from the following description.

[0011] Technical Solution

[0012] In one general aspect, a method for performing beam recovery in a wireless communication system is provided, the method being performed by a user equipment (UE) and comprising: receiving a beam reference signal (BRS) for beam management from an enhanced Node B (eNB); sending a control signal for a beam failure recovery request to the eNB when a beam failure event is detected; and reporting beam measurement results to the eNB in ​​specific resources when a beam report is triggered, wherein the control signal includes indication information indicating whether a replacement beam exists, wherein the replacement beam is a reference signal having a channel quality greater than a specific channel quality among reference signals configured for beam management.

[0013] The indication information may be information about a preferred link associated with a preset non-periodic beam reporting setting, information about a preferred resource setting associated with a preset non-periodic beam reporting setting, or information about a preferred resource set associated with a preset non-periodic beam reporting setting.

[0014] The control signal uses the same time resource as the physical random access channel (PRACH), and the control signal can be code division multiplexed (CDM) or frequency division multiplexed (FDM) with the PRACH in the time resource.

[0015] The control signal can be sent through the Physical Uplink Control Channel (PUCCH), and depending on whether there is an alternative beam, the control signal can use different time / frequency resources, different sequence sets and / or different uplink control information (UCI).

[0016] Different sequence sets can be distinguished by root sequence index or cyclic shift value.

[0017] The method may further include receiving an indication message from the eNB indicating triggering of beam reporting, and may trigger the beam reporting based on the indication message.

[0018] The indication message may include at least one of the following: information about valid or invalid links among the settings pre-associated as measurement settings, information about valid or invalid resource settings among the settings pre-associated as measurement settings, information about valid or invalid resource sets among the settings pre-associated as measurement settings, and beam reporting mode setting information.

[0019] In the measurement setup, one report setup and two resource setups may be connected via a link, or one report setup and one resource setup may be connected via a link.

[0020] The beam reporting mode setting information may be a first mode in which aperiodic reference signal transmission and aperiodic beam reporting are triggered together, or a second mode in which only aperiodic beam reporting is triggered.

[0021] When the beam reporting mode setting information is set to the first mode, the specific resource may be an aperiodic resource setting or an aperiodic resource set among resource settings or resource sets configured by radio resource control (RRC).

[0022] The specific resource may be a resource activated in the same time slot as the time slot in which the indication message is received, or a resource activated after the time slot in which the indication message is received.

[0023] When the beam reporting mode setting information is set to the second mode, the specific resource may be a periodic or semi-persistent resource setting or resource set in a resource setting or resource set configured by RRC.

[0024] The specific resource may be a resource activated before the time slot in which the indication message is received.

[0025] In another general aspect, a user equipment (UE) for performing beam recovery in a wireless communication system is provided, the UE comprising: a radio frequency (RF) module configured to send and receive radio signals; and a processor functionally connected to the RF module, wherein the processor is configured to: receive a beam reference signal (BRS) for beam management from an enhanced Node B (eNB); send a control signal for a beam failure recovery request to the eNB when a beam failure event is detected; and report beam measurement results to the eNB in ​​specific resources when a beam report is triggered, wherein the control signal includes information indicating whether there is a replacement beam, wherein the replacement beam is a reference signal having a channel quality greater than a specific channel quality among the reference signals configured for beam management.

[0026] Beneficial effects

[0027] This specification defines a beam recovery process when a beam failure event occurs, thereby solving the beam blocking problem caused by the movement of UE, etc.

[0028] In addition, the present specification has an advantageous effect in efficiently performing beam recovery by notifying an enhanced Node B (eNB) whether there is an alternative beam for a UE and thereby performing different operations by the eNB.

[0029] Effects obtainable in the present disclosure are not limited to the above-described effects, and other technical effects not described above can be apparently understood by those skilled in the art to which the present disclosure pertains from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

[0031] Figure 1 is a diagram showing an example of a system structure of New Rat (NR) to which the method proposed in the present disclosure can be applied.

[0032] Figure 2 The relationship between uplink frames and downlink frames in a wireless communication system to which the method proposed in the present disclosure can be applied is shown.

[0033] Figure 3 An example of a resource grid supported by a wireless communication system to which the method proposed in the present disclosure can be applied is shown.

[0034] Figure 4 An example of a resource grid for each antenna parameter set to which the method proposed in this disclosure can be applied is shown.

[0035] Figure 5 An example of a block diagram showing an analog beamformer and transmitter configured as an RF chain.

[0036] Figure 6 An example of a block diagram showing a digital beamformer and transmitter configured as an RF chain.

[0037] Figure 7 An example of an analog beam scanning method according to various embodiments of the present disclosure is shown.

[0038] Figure 8 is a diagram showing an example of a PUSCH CSI reporting mode.

[0039] Figure 9 is a diagram showing the PUCCH CSI reporting mode.

[0040] Figure 10 An example of network operation proposed in the specification according to whether a replacement beam exists is shown.

[0041] Figure 11 is a diagram illustrating an example of a beam correlation setting method that can be applied to the method proposed in this specification.

[0042] Figure 12 is a flowchart illustrating a method for performing beam recovery proposed in this specification.

[0043] Figure 13 An example of a block diagram of a wireless communication device according to an embodiment of the present disclosure is shown.

[0044] Figure 14 An example of a block diagram of a communication device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0045] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description disclosed below with reference to the accompanying drawings is intended to describe illustrative embodiments of the present invention and is not intended to represent the only embodiment of the present invention. The following detailed description includes specific details to provide a complete understanding of the present invention. However, it should be understood by those skilled in the art that the present invention can be practiced without introducing these specific details.

[0046] In some cases, to avoid obscuring the subject matter of the present invention, well-known structures and devices may be omitted, or may be depicted in the form of block diagrams with regard to the core functions of each structure and device.

[0047] In this document, a base station is considered a terminal node of a network that performs direct communication with a user equipment terminal (UE). In this document, specific operations that are considered to be performed by a base station may be performed by a higher-level node of the base station, depending on the situation. In other words, it is apparent that in a network composed of multiple network nodes including a base station, various operations performed for communication with a user equipment terminal (UE) may be performed by the base station or by network nodes other than the base station. The term base station (BS) may be replaced by terms such as fixed station, Node B, evolved Node B (eNB), base transceiver system (BTS), access point (AP), or generalized NB (gNB). Furthermore, a terminal may be fixed or mobile, and the term may be replaced by terms such as user equipment (UE), mobile station (MS), user terminal (UT), mobile subscriber station (MSS), subscriber station (SS), advanced mobile station (AMS), wireless terminal (WT), machine type communication (MTC) device, machine-to-machine (M2M) device, or device-to-device (D2D) device.

[0048] In the following, downlink (DL) refers to communication from a base station to a terminal, while uplink (UL) refers to communication from a terminal to a base station. In downlink transmission, the transmitter can be part of the base station, and the receiver can be part of the terminal. Similarly, in uplink transmission, the transmitter can be part of the terminal, and the receiver can be part of the base station.

[0049] Specific terms used in the following description are introduced to help understanding of the present invention, and the specific terms may be used in different ways as long as they do not depart from the technical scope of the present invention.

[0050] The techniques described below can be used for various types of wireless access systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), or non-orthogonal multiple access (NOMA). CDMA can be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM (EDGE). OFDMA can be implemented using radio technologies such as IEEE 802.11 (WiFi), IEEE 802.16 (WiMAX), IEEE 802-20, or Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA, which employs OFDMA for downlink and SC-FDMA for uplink transmission. LTE-A (Advanced) is an evolved version of the 3GPP LTE system.

[0051] The embodiments of the present invention may be supported by standard documents published for at least one wireless access system, such as IEEE 802, 3GPP, and 3GPP2. In other words, the aforementioned documents provide backup for steps or parts of the embodiments of the present invention that are not described in order to clearly illustrate the technical principles of the present invention. Furthermore, all terms disclosed in this document may be described by the aforementioned standard documents.

[0052] For the purpose of clarity, description is mainly given about 3GPP LTE / LTE-A, but technical features of the present invention are not limited to a specific system.

[0053] Definition of terms

[0054] eLTE eNB: eLTE eNB is an evolution of eNB that supports connections to EPC and NGC.

[0055] gNB: A node that supports NR in addition to connectivity with NGC

[0056] New RAN: Radio access network that supports NR or E-UTRA or interacts with NGC

[0057] Network Slicing: Network slicing is a network defined by an operator to provide solutions optimized for specific market scenarios that require specific requirements and ranges between devices.

[0058] Network Function: A network function is a logical node in the network infrastructure with a well-defined external interface and well-defined functional operations.

[0059] NG-C: Control plane interface for the NG2 reference point between the new RAN and NGC NG-U: User plane interface for the NG3 reference point between the new RAN and NGC

[0060] Non-standalone NR: A deployment configuration where the gNB requires an LTE eNB as the anchor point for the control plane connection to the EPC or an eLTE eNB as the anchor point for the control plane connection to the NGC.

[0061] Non-standalone E-UTRA: A deployment configuration where the eLTE eNB requires a gNB as the anchor point for the control plane connection to the NGC.

[0062] User Plane Gateway: Termination point of the NG-U interface

[0063] General system

[0064] Figure 1 is a block diagram illustrating an example of an overall structure of a New Radio (NR) system in which the method proposed in the present disclosure may be implemented.

[0065] refer to Figure 1 NG-RAN is composed of gNBs that provide NG-RA user plane (new AS sublayer / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol terminals for UE (user equipment).

[0066] gNBs are connected to each other via the Xn interface.

[0067] The gNB is also connected to the NGC via the NG interface.

[0068] More specifically, the gNB is connected to the Access and Mobility Management Function (AMF) via the n2 interface and to the User Plane Function (UPF) via the n3 interface.

[0069] NR (New RAT) parameter set and frame structure

[0070] In NR systems, multiple parameter sets can be supported. The parameter set can be defined by subcarrier spacing and CP (cyclic prefix) overhead. The spacing between multiple subcarriers can be derived by scaling the basic subcarrier spacing by an integer N (or μ). In addition, although it is assumed that very low subcarrier spacing is not used at very high subcarrier frequencies, the parameter set to be used can be selected independently of the frequency band.

[0071] In addition, in the NR system, various frame structures based on multiple parameter sets can be supported.

[0072] Hereinafter, an Orthogonal Frequency Division Multiplexing (OFDM) parameter set and a frame structure that can be considered in the NR system will be described.

[0073] Table 1 defines the multiple OFDM parameter sets supported in the NR system.

[0074]

Table 1

[0075]

[0076] Regarding the frame structure in the NR system, the size of each field in the time domain is expressed as a multiple of the time unit. In this case, Δf max =480·10 3 and / N r =4096, DL and UL transmissions are configured with T f =(Δf max N f / 100)·T s =10ms portion of the radio frame. A radio frame consists of ten subframes, each with T sf =(Δf max N f / 1000)·T s =1 ms portion. In this case, there are UL frame sets and DL frame sets.

[0077] Figure 2 The diagram illustrates the relationship between UL frames and DL frames in a wireless communication system in which the method proposed in the present disclosure can be implemented.

[0078] like Figure 2 As shown, a UL frame number I from a user equipment (UE) needs to be sent before the start of the corresponding DL frame in the UE.

[0079] Regarding the parameter set μ, according to the subframe in ascending order and according to the The time slots are numbered in ascending order. A time slot is composed of Consecutive OFDM symbols, and It is determined based on the parameter set and time slot configuration in use. The time slot in the subframe The start of the OFDM symbol in the same subframe in time Start alignment.

[0080] Not all UEs are capable of transmitting and receiving simultaneously, and this means that not all OFDM symbols in a DL slot or a UL slot are available.

[0081] Table 2 shows the number of OFDM symbols per slot of the normal CP in the parameter set μ, and Table 3 shows the number of OFDM symbols per slot of the extended CP in the parameter set μ.

[0082]

Table 2

[0083]

[0084]

Table 3

[0085]

[0086] NR Physics Resources

[0087] Regarding the physical resources in the NR system, we can consider antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc.

[0088] In the following, the above-mentioned physical resources that can be considered in the NR system will be described in more detail.

[0089] First, regarding antenna ports, the antenna ports are defined so that the channel through which symbols on one antenna port are transmitted can be inferred from the channel through which symbols on the same antenna port are transmitted. When the large-scale properties of the channel through which symbols on one antenna port are received can be inferred from the channel through which symbols on the other antenna port are transmitted, the two antenna ports can be in a QC / QCL (quasi-co-located or quasi-co-located) relationship. Here, the large-scale properties may include at least one of delay spread, Doppler spread, Doppler shift, average gain, and average delay.

[0090] Figure 3 An example of a resource grid supported in a wireless communication system in which the method proposed in the present disclosure can be implemented is illustrated.

[0091] refer to Figure 3 , the resource grid is in the frequency domain subcarriers, and each subframe is composed of 14·2μ OFDM symbols, but the present disclosure is not limited thereto.

[0092] In the NR system, the signal is transmitted by subcarriers and OFDM symbols are described by one or more resource grids. Indicates the maximum transmission bandwidth and may vary not only between parameter sets, but also between uplink and downlink.

[0093] In this case, if Figure 4 As shown in FIG, one resource grid may be configured for each parameter set μ and antenna port p.

[0094] Figure 4 The diagram shows an example of a resource grid for each antenna port and parameter set applicable to the method proposed in this specification.

[0095] Each element of the resource grid for parameter set μ and antenna port p is called a resource element and is uniquely identified by an index pair (k, l). is an index in the frequency domain, and Refers to the position of the symbol on the subframe. The index pair (k, l) is used to refer to the resource element in the time slot. Here,

[0096] Resource elements for numerology set μ and antenna port p Corresponding to complex values When there is no risk of confusion, or when no particular antenna port or parameter set is specified, the indices p and μ may be dropped, and thus the complex values ​​may be or

[0097] In addition, physical resource blocks are defined as In the frequency domain, the physical resource blocks are from 0 to Number. Number of physical resource blocks in the frequency domain n PRB The relationship between and resource element (k, l) can be given by Equation 1.

[0098] [Equation 1]

[0099]

[0100] Regarding carrier parts, the UE can be configured to receive or transmit a carrier part using only a subset of the resource grid. In this case, the set of resource blocks that the UE is configured to receive or transmit ranges from 0 to Start numbering.

[0101] Uplink control channel

[0102] The physical uplink control signaling should at least be able to carry hybrid ARQ acknowledgments, CSI reports (including beamforming information if possible) and scheduling requests.

[0103] For the UL control channel supported by the NR system, at least two transmission methods are supported.

[0104] An uplink control channel can be transmitted within a short duration around the last transmitted uplink symbol of a time slot. In this case, the uplink control channel is time-division multiplexed and / or frequency-division multiplexed with the uplink (UL) data channel in the time slot. For short-duration uplink control channels, one symbol unit of the time slot is supported.

[0105] - In the case where the physical resource blocks (PRBs) used for short UCI and data do not overlap, short uplink control information (UCI) and data are frequency-division multiplexed at least between UEs.

[0106] - To support time division multiplexing (TDM) of short PUCCHs from different UEs in the same slot, a mechanism is supported for informing the UE whether the symbols of short PUCCHs are supported in the slot at least at 6 GHz or higher.

[0107] Regarding 1 symbol duration, at least: 1) when the reference signal (RS) is multiplexed, UCI and RS are multiplexed into a given OFDM symbol through a frequency division multiplexing (FDM) scheme, and 2) in the same time slot, the subcarrier spacing and short duration PUCCH between downlink (DL) and uplink (UL) data are the same as each other.

[0108] At least, short-duration PUCCH during 2-symbol duration is supported. In this case, the subcarrier spacing between downlink (DL) and uplink (UL) data and short-duration PUCCH are the same as each other in the same time slot.

[0109] - At least, semi-static configuration is supported, where the PUCCH resources of a given UE in a timeslot can be time-division multiplexed within a given duration, ie, short PUCCHs of different UEs.

[0110] -PUCCH resources include time domain and frequency domain, and if applicable, PUCCH resources include code domain.

[0111] - From the UE's perspective, the short-duration PUCCH may extend to the end of the slot. In this case, no explicit gap symbol is required after the short-duration PUCCH.

[0112] - Regarding time slots with a short UL part (ie, time slots centered on DL), when data is scheduled in the short uplink part, "short UCI" and data can be frequency-division multiplexed by one UE.

[0113] To improve coverage, the uplink control channel may be sent over multiple uplink symbols for a long duration. In this case, the uplink control channel is frequency-division multiplexed with the uplink data channel in a time slot.

[0114] - At least, with a design with low peak-to-average power ratio (PAPR), UCI carried by a long-duration UL control channel can be transmitted in one time slot or multiple time slots.

[0115] - In at least some cases, transmissions using multiple time slots within a total duration (e.g., 1 ms) are allowed.

[0116] - For long duration uplink control channels, time division multiplexing (TDM) between RS and UCI is supported for DFT-S-OFDM.

[0117] - The long UL part of a slot can be used to transmit long duration PUCCH. That is, long duration PUCCH is supported both for UL-only slots and for slots with a variable number of symbols consisting of a minimum of four symbols.

[0118] - At least for 1 or 2-bit UCI, the UCI may be repeated in N (N>1) slots, and the N slots may be contiguous or non-contiguous in slots where long-duration PUCCH is allowed.

[0119] At least for long PUCCH, simultaneous transmission of PUSCH and PUCCH is supported. That is, uplink control for PUCCH resources is sent even when data is present. In addition to simultaneous transmission of PUCCH and PUSCH, UCI in PUSCH is also supported.

[0120] -Supports time slot hopping within TTI.

[0121] -Support for DFT-s-OFDM waveform.

[0122] Supports transmit antenna diversity.

[0123] TDM and FDM between short-duration PUCCH and long-duration PUCCH are supported for other UEs in at least one time slot. In the frequency domain, PRB (or multiple PRBs) is the minimum resource unit size for UL control channels. When hopping is used, frequency resources and hopping may not extend to the carrier bandwidth. In addition, UE-specific RS is used for NR-PUCCH transmission. The set of PUCCH resources is configured by high-layer signaling, and the PUCCH resources within the configured set are indicated by downlink control information (DCI).

[0124] As part of the DCI, the timing between data reception and hybrid ARQ acknowledgment transmission should be dynamically indicated (at least in conjunction with RRC). A combination of semi-static configuration and dynamic signaling (at least for some types of UCI information) is used to determine the PUCCH resources for "long and short PUCCH formats." Here, PUCCH resources include the time domain and frequency domain, and, if applicable, the code domain. In the case of simultaneous transmission of UCI and data, UCI is used on the PUSCH, i.e., a portion of the scheduling resources used for UCI is supported.

[0125] In addition, at least a single HARQ-ACK bit uplink transmission is supported. In addition, a mechanism is supported that implements frequency diversity. In addition, in the case of ultra-reliable and low-latency communication (URLLC), the time interval between scheduling (SR) resources configured for a UE can be less than one time slot.

[0126] Beam management

[0127] Beam management in the RN system is defined as follows.

[0128] Beam management: A set of L1 / L2 procedures used to acquire and maintain a set of TRPs and / or UE beams that can be used for DL ​​and UL transmission and reception, including at least the following:

[0129] -Beam determination: The operation by which the TRP or UE selects its own transmit / receive beam

[0130] -Beamformation: The operation by which the TRP or UE measures the received beamformed signal

[0131] - Beam reporting: An operation in which the UE reports information about the beamformed signal based on beam measurements.

[0132] - Beam scanning: An operation in which a spatial domain is covered using a transmitted and / or received beam during a time interval by a predetermined method

[0133] In addition, the correspondence between TRP and Tx / Rx beam in UE is defined as follows.

[0134] -Maintain Tx / Rx beam correspondence in TRP when at least one of the following is met.

[0135] –TRP can determine the TRP Rx beam used for DL ​​reception based on the UE's DL measurements of one or more Tx beams of the TRP.

[0136] –TRP can determine the TRPTx beam used for DL ​​transmission based on the UL measurement of TRP of one or more Rx beams of TRP.

[0137] -Maintain Tx / Rx beam correspondence in the UE when at least one of the following is satisfied:

[0138] -The UE may determine the UE Tx beam to use for UL transmission based on the UE's DL measurements for one or more Rx beams of the UE.

[0139] -The UE may determine the UE Rx beam to use for DL ​​reception based on the TRP indication based on UL measurements of one or more Tx beams.

[0140] -TRP supports performance indication of UE beam corresponding related information.

[0141] The following DL L1 / L2 beam management procedures are supported in a single TRP or multiple TRPs.

[0142] P-1: used to enable UE measurements on different beams to support TRP Tx beam / UE Rx beam selection

[0143] - In case of beamforming in TRP, different beam sets typically include intra / inter TRP Tx beam scanning. For beamforming in UE, it typically includes UE Rx beam scanning from different beam sets.

[0144] P-2: UE measurements for different TRP Tx beams are used to change inter / intra TRP Tx beams.

[0145] P-3: When the UE uses beamforming, the measurement of the same TRP Tx beam is used to change the UE Tx beam.

[0146] In operations related to P-1, P-2 and P-3, at least non-periodic reporting triggered by the network is supported.

[0147] The UE measurements for beam management based on RS (at least CSI-RS) consist of K (total number of beams), and the UE reports the measurement results of N selected Tx beams. Here, N is not necessarily a fixed number. Mobility procedures based on RS are not excluded. The reported information includes information indicating the measurement quality of N beams, where at least N < K, and N DL Tx beams. In particular, the UE may report N' CRIs (CSI-RS resource indicators) for K' > 1 non-zero power (NZP) CSI-RS resources.

[0148] For beam management, the UE can be configured with higher layer parameters as described below.

[0149] - N ≥ 1 reporting settings, M ≥ 1 resource settings

[0150] - The link between the reporting settings and the resource settings is set in the agreed CSI measurement settings.

[0151] - The resources and reporting settings support P-1 and P2 based on CSI-RS.

[0152] - P-3 can be supported regardless of the reporting settings.

[0153] - The reporting settings at least include the following.

[0154] - Information including the selected beams

[0155] - L1 measurement reports

[0156] - Time domain operations (e.g., aperiodic operations, periodic operations, and semi-persistent operations)

[0157] - Frequency granularity in the case of supporting various frequency granularities

[0158] - The resource settings at least include the following

[0159] - Time domain operations (e.g., aperiodic operations, periodic operations, semi-persistent operations)

[0160] - RS type: at least NZP CSI-RS

[0161] - At least one CSI-RS resource set, each CSI-RS resource set including K > 1 RS resources (some parameters of the K CSI-RS resources may be the same. For example, port number, time domain operation, density, and period).

[0162] In addition, considering L groups where L > 1, NR supports the following beam reporting.

[0163] - Information indicating the smallest group

[0164] - Measurement quantity of N1 beam (supports L1 RSRP and CSI reporting) (when using CSI-RS to obtain CSI)

[0165] -When applicable, indicates information of N1 DL Tx beams.

[0166] As described above, group-based beam reporting can be configured on a UE-by-UE basis. Additionally, group-based beam reporting can be disabled on a UE-by-UE basis (e.g., when L=1 or Nl=1).

[0167] NR can trigger the mechanism for UE to recover from beam failure.

[0168] When the quality of the associated control channel beam pair link is sufficiently low (e.g., compared to a threshold, an associated timer expires), a beam failure event occurs. When a beam error occurs, a mechanism for recovering from beam failure (or error) is triggered.

[0169] The network is explicitly configured for the UE with resources to send UL signals for recovery purposes. Configuration of resources is supported in the point where the eNB is listening from all or some directions (eg random access).

[0170] The UL Tx / resource reporting the beam error may be in the same time instance as PRACH (resources orthogonal to PRACH) or in a different instance than PRACH (configurable for the UE). Transmission of a DL signal may be supported to enable the UE to monitor the beam in order to identify new potential beams.

[0171] NR supports beam management regardless of the beam-related indication. When a beam-related indication is provided, information about UE-side beamforming for CSI-RS-based measurement / reception processing can be indicated to the UE through QCL. As QCL parameters to be supported in NR, not only parameters about delay, Doppler, average gain, etc. used in the LTE system are scheduled to be added, but also spatial parameters for beamforming at the Tx end are scheduled to be added, and may include arrival angle-related parameters according to UE Rx beamforming and departure angle-related parameters according to eNB Rx beamforming. NR supports the use of the same or different beams in control channel and corresponding data channel transmissions.

[0172] To transmit NR-PDCCH that supports robustness against beam pair blocking, the UE may be configured to simultaneously monitor NR-PDCCH on M beam pair links, where M ≥ 1 and the maximum value of M depends at least on the UE capability.

[0173] The UE may be configured to monitor NR-PDCCH on different beam-pair links in different NR-PDCCH OFDM symbols. Parameters related to the UE beam setting for monitoring NR-PDCCH on multiple beam-pair links may be configured via higher layer signaling or via MAC CE and / or may be considered in the search space design.

[0174] At least, NR supports the indication of the spatial QCL hypothesis between the DL RS antenna ports and the DL RS antenna ports to demodulate the DL control channel. Candidate signaling methods for beam indication of NR-PDCCH (i.e., methods for monitoring the configuration of NR-PDCCH) are MAC CE signaling, RRC signaling, DCI signaling, a combination of standardized transparent and / or implicit methods, and a combination of methods for signaling the above.

[0175] To receive unicast DL data channels, NR supports the indication of spatial QCL assumption between the DL RS antenna port and the DMRS antenna port of the DL data channel.

[0176] Information indicating the RS antenna port is displayed through DCI (Downlink Grant). In addition, this information indicates the RS antenna port, which is QCL with the DMRS antenna port. Different sets of DMRS antenna ports for DL ​​data channels can be expressed as different sets of RS antenna ports QCL.

[0177] Hybrid Beamforming

[0178] Existing beamforming technology using multiple antennas can be roughly divided into analog beamforming technology and digital beamforming technology according to locations, to which a beamforming weight vector / precoding vector is applied.

[0179] The analog beamforming method is a representative beamforming method applied to the initial multi-antenna structure. The analog beamforming method may refer to a technology that divides a digitally processed analog signal into multiple paths and performs beamforming through a phase shifter (PS) and a power amplifier (PA) for each path.

[0180] For analog beamforming, analog signals derived from a single digital signal need to be processed by the PA and PS connected to each antenna. That is, in the analog stage, complex weights are processed by the PS and PA.

[0181] Figure 5 An example of a block diagram showing a transmitter consisting of an analog beamformer and RF chain is shown. This diagram is for explanatory purposes only. Figure 5 , and does not limit the scope of the present disclosure.

[0182] exist Figure 5In the figure, the radio frequency (RF) chain refers to the processing block for converting baseband (BB) signals into analog signals, and its structure is shown in the figure. In the analog beamforming method, the beamforming accuracy is determined by the device characteristics of the PS and PA, and due to the control characteristics of the devices, the analog beamforming method can be advantageous in narrowband transmission.

[0183] In addition, in the analog beamforming method, since it is difficult to implement the hardware structure of multi-stream transmission, the multiplexing gain for increasing the transmission rate is relatively low. In this case, it may be difficult to perform beamforming for each UE based on orthogonal resource assignment.

[0184] In contrast, in the digital beamforming method, in order to maximize diversity and multiplexing gain in a Multiple Input Multiple Output (MIMO) environment, beamforming is performed using BB processing in the digital stage.

[0185] Figure 6 FIG is a block diagram showing a transmitter including a digital beamformer and a radio frequency (RF) chain. FIG is shown for convenience of explanation only. Figure 6 , and does not limit the scope of the present disclosure.

[0186] exist Figure 6 In the case of , precoding can be performed during the BB process, making beamforming possible. Here, the RF chain includes the PA. This is because the complex weights derived for beamforming are directly applied to the transmitted data.

[0187] Furthermore, because beamforming can be performed differently for each user, simultaneous beamforming for multiple users is supported. Furthermore, because beamforming is performed independently for each user assigned orthogonal resources, scheduling flexibility is high and a transmitter tailored to the system's objectives can be employed. Furthermore, if MIMO orthogonal frequency division multiplexing (OFDM) technology is applied in a broadband transmission environment, independent beams can be formed for each subcarrier.

[0188] Therefore, the digital beamforming method can optimize the maximum single-user transmission rate based on enhanced beam gain and system capacity enhancement. Based on the above characteristics, MIMO technology based on digital beamforming has been introduced in current 3G / 4G systems.

[0189] In NR systems, a massive MIMO environment can be considered, in which the number of transmit and receive antennas increases significantly. Typically, in cellular communications, the maximum number of transmit and receive antennas used in a MIMO environment is assumed to be eight. However, in a massive MIMO environment, the number of transmit and receive antennas may increase to dozens or even hundreds.

[0190] In this case, if the above-mentioned digital beamforming technology is applied to a massive MIMO environment, the transmitter needs to perform signal processing for hundreds of antennas through BB processing for digital signal processing. Therefore, the complexity of signal processing increases significantly, and as many RF chains as antennas are required, and therefore the complexity of hardware implementation may increase significantly.

[0191] Furthermore, the transmitter needs to perform independent channel estimation for each antenna. In addition, in FDD systems, because the transmitter requires feedback information about the massive MIMO channel including all antennas, the pilot and / or feedback overhead may increase significantly.

[0192] On the other hand, if the above analog beamforming technology is applied to a massive MIMO environment, the hardware complexity of the transmitter is relatively low.

[0193] In contrast, the performance enhancement of using multiple antennas is very low, and the flexibility of resource allocation may be reduced. In particular, in broadband transmission, it may be difficult to control the beam of each frequency.

[0194] Therefore, in a massive MIMO environment, a hybrid type configuration of transmission is required in which an analog beamforming structure and a digital beamforming structure are combined, rather than a configuration of a transmitter in which one of the analog beamforming structure and the digital beamforming structure is selected.

[0195] Analog beam scanning

[0196] Typically, pure analog beamforming transceivers and hybrid beamforming transceivers can employ analog beamforming. In this regard, analog beam scanning can enable the simultaneous estimation of a single beam. Therefore, the training time required for beam scanning is proportional to the total number of beam candidates.

[0197] As mentioned above, in analog beamforming, it is necessary to perform beam scanning in the time domain for transceiver beam estimation. In this case, the estimated time t of all transceiver beams can be calculated as s It is expressed as the following equation 2.

[0198] Equation 2

[0199] T S =t s ×(K T ×K R )

[0200] In Equation 2, t s represents the time required for one beam scan, K T represents the number of transmit beams, and K R Indicates the number of receive beams.

[0201] Figure 7 An example of an analog beam scanning method according to various embodiments of the present disclosure is shown. Figure 7 , and the Figure 7 It does not limit the scope of the present disclosure.

[0202] exist Figure 7 In the case of T is L, and the total number of receiving beams is K R is 1. In this case, the total number of candidate beams is L, and therefore, a time interval L is required in the time domain.

[0203] In other words, for analog beam estimation, 1 beam estimation can be performed in a single time interval, and therefore, as Figure 7 As shown in , the total L beam estimations (P1 to PL) require L time intervals. After the simulated beam estimation process is complete, the UE feeds back an identifier (e.g., ID) of the beam with the strongest signal strength to the eNB. That is, as the number of beams increases due to an increase in the number of transmit and receive antennas, a longer training time may be required.

[0204] Because analog beamforming changes the magnitude and phase angle of a continuous waveform in the time domain after the DAC, unlike digital beamforming, a training interval must be maintained for each beam. Therefore, a longer training interval minimizes system efficiency degradation (in other words, increases system loss).

[0205] Channel State Information (CSI) feedback

[0206] In most cellular systems including the LTE system, a UE receives a pilot signal or a reference signal for channel estimation from an eNB to calculate CSI, and reports the calculated CSI to the eNB.

[0207] The eNB transmits a data signal based on the CSI fed back from the UE.

[0208] The CSI fed back from the UE in the LTE system includes CQI (Channel Quality Information), PMI (Precoding Matrix Index), and RI (Rank Indicator).

[0209] CQI feedback is radio channel quality information reported for the purpose of providing guidance on whether to apply a modulation and coding scheme (MCS) when the eNB transmits data (for the purpose of link adaptation).

[0210] If the channel quality between the eNB and the UE is high, the UE can feed back a higher CQI value, so that the eNB will send data by applying a relatively high modulation order and a low coding rate; conversely, the UE can feed back a low CQI value, so that the eNB will send data by applying a relatively low modulation order and a high coding rate.

[0211] PMI feedback is the preferred precoding matrix information that is provided to the eNB to provide guidance on which MIMO precoding scheme to adopt if the eNB is equipped with multiple antennas.

[0212] The UE estimates the downlink MIMO channel between the eNB and UE based on the reference signal, and thus suggests the eNB to apply a MIMO precoding scheme through PMI feedback.

[0213] In the LTE system, only linear MIMO precoders that can be expressed in matrix form are considered in PMI configuration.

[0214] The eNB and the UE share a codebook including multiple precoding matrices, and each MIMO precoding matrix in the codebook has a unique index.

[0215] Therefore, the UE minimizes the amount of feedback information by feeding back the index corresponding to the most preferred MIMO precoding matrix within the codebook.

[0216] The PMI value does not necessarily consist of one index. For example, when the number of transmitter antenna ports in the LTE system is 8, it is configured so that the final 8tx MIMO precoding matrix can be derived only when two indices (the first PMI and the second PMI) are combined.

[0217] RI feedback is information about the preferred number of transmission layers provided to the eNB to provide guidance on the number of transmission layers preferred by the UE if multiple antennas are installed in the eNB and UE, thereby enabling multi-layer transmission through spatial multiplexing.

[0218] RI is highly correlated with PMI. This is because the eNB should know which precoding to apply to each layer based on the number of transmission layers.

[0219] When PMI / RI feedback configuration is achieved, feedback can be enabled by defining PMI for each layer after configuring the PMI codebook with reference to a single-layer transmission. However, the disadvantage of this approach is that the amount of PMI / RI feedback information increases significantly due to the increase in the number of transmission layers.

[0220] Therefore, in the LTE system, a PMI is defined for each number of transmission layers. That is, for R-layer transmission, N Nt×R matrices are defined in the codebook (where R represents the number of layers, N represents the number of layers, and N represents the number of layers). tdenotes the number of transmit antenna ports, and N denotes the size of the codebook).

[0221] Therefore, in the LTE system, the size of the PMI codebook is defined regardless of the number of transmission layers. As a result, since PMI.RI is defined in this configuration, the number of transmission layers (R) coincides with the rank value of the precoding matrix (Nt XR matrix), and the terminology of the rank indicator (RI) is therefore used.

[0222] Unlike PMI / RI in the LTE system, PMI / RM used in this specification is not limited to an index value indicating a precoding matrix represented as an NT×R matrix and a rank value of the precoding matrix.

[0223] The PMI used in this specification indicates information related to the preferred MIMO precoder among the MIMO precoders that can be applied to the transmitter, and the form of the precoder is not limited to the linear precoder that can be represented in matrix form in the LTE system. In addition, the RI used in this specification has a broader meaning than the RI used in LTE and includes all feedback information indicating the preferred number of transmission layers.

[0224] CSI information may be acquired in the entire system frequency domain or in certain frequency domains. Particularly in a wideband system, it may be useful for each UE to acquire CSI information on certain preferred frequency domains (eg, subbands) and provide feedback on the acquired CSI information.

[0225] In the LTE system, CSI feedback is performed through an uplink channel, and generally, periodic CSI feedback is performed through a Physical Uplink Control Channel (PUCCH), while aperiodic CSI feedback is performed through a Physical Uplink Shared Channel (PUSCH) which is an uplink data channel.

[0226] Aperiodic CSI feedback refers to providing feedback temporarily only when the eNB needs CSI feedback information, and in this case, the eNB triggers CSI feedback through a downlink control channel such as PDCCH / ePDCCH.

[0227] In the LTE system, Figure 8 The PUSCH reporting mode shown in identifies which information the UE needs to feed back when CSI feedback is triggered, and notifies the UE in advance through the uplink layer which PUSCH CSI reporting mode the UE needs to operate.

[0228] Figure 8 is a diagram showing an example of a PUSCH CSI reporting mode.

[0229] A PUCCH CSI reporting mode for periodic CSI feedback over the PUCCH is also defined.

[0230] Figure 9 is a diagram showing an example of a PUCCH CSI reporting mode.

[0231] The PUCCH has a smaller payload size than the PUSCH, and thus it is difficult to transmit CSI information all at once.

[0232] Therefore, in each reporting mode, the timing for transmitting CQI and PMI is different from the timing for transmitting RI. For example, in reporting mode 1-0, RI is transmitted separately at the PUCCH transmission timing, and wideband CQI is transmitted at another PUCCH transmission timing. The PUCCH report type is defined according to the type of CSI information configured at a specific PUCCH transmission timing. For example, in the above example, the report type in which RI is transmitted separately corresponds to type 3, and the report type in which wideband CQI is transmitted separately corresponds to type 4. The periodicity and offset value of RI feedback and the periodicity and offset value of CQI / PMI feedback are set to the UE through uplink messages.

[0233] The CSI feedback information is included in uplink control information (UCI).

[0234] Reference Signals in LTE

[0235] In an LTE system, the use of pilots or reference signals (RS) can be roughly divided as follows.

[0236] 1. Measurement RS: pilot for channel state estimation

[0237] A. CSI measurement / reporting purpose (short-term measurement): for purposes such as link adaptation, rank adaptation, and closed-loop MIMO precoding.

[0238] B. Long-term measurement / reporting purposes: handover, cell selection / reselection, etc.

[0239] 2. Demodulation RS: pilot for physical channel reception

[0240] 3. Positioning RS: pilot signal used for UE position estimation

[0241] 4.MBSFN RS: Pilot for Multicast / Broadcast Services

[0242] In LTE Release-8, cell-specific RS (CRS) is used for measurement (Purpose 1A / B) and demodulation (Purpose 2) of most downlink physical channels, but to address the RS overhead problem caused by the increase in the number of antennas, starting from LTE Advanced (Release-10), CSI-RS is only used for CSI measurement (Purpose 1A), and UE-specific RS is only used for receiving downlink data channels (PDSCH).

[0243] CSI-RS is an RS designed specifically for CSI measurement and feedback. It features significantly lower RS ​​overhead compared to CRS, and while CRS supports four antenna ports, CSI-RS is designed to support up to eight antenna ports. Because UE-specific RSs are specifically designed for demodulation of data channels, they apply the MIMO precoding technology used in data transmission to pilot signals (precoded RSs).

[0244] Therefore, unlike CRS and CSI-RS, UE-specific RSs do not have to be transmitted as many as the number of antenna ports, and UE-specific RSs as many as the number of transmission layers (transmission ranks) can be transmitted.

[0245] In addition, the UE-specific RS is transmitted in the same resource region as the data channel resource region allocated to each UE by the scheduler of the eNB in ​​order to receive the data channel of the corresponding UE, and thus, the UE-specific RS is a UE-specific RS.

[0246] CRS is always sent in the same pattern in the system bandwidth to be used by every UE for measurement and demodulation, and is therefore cell-specific.

[0247] In LTE UL, a sounding RS (SRS) is designed as a measurement RS, a demodulation RS (DMRS) is designed for an uplink data channel (PUSCH), and a DMRS is designed for an uplink control channel (PUCCH) for ACK / NACK and CSI feedback.

[0248] Beam management and beam restoration

[0249] The eNB may request periodic CSI reporting, semi-persistent CSI reporting (which means that periodic CSI reporting is activated only during a specific time period, or continuous and multiple CSI reporting is performed), or aperiodic CSI reporting from the UE.

[0250] Here, in a period in which periodic and semi-persistent (SP) CSI reporting are activated, uplink (UL) resources (eg, PUCCH in LTE) for CSI reporting in a specific period are allocated to the UE.

[0251] For UE's CSI estimation, the eNB is required to transmit a downlink (DL) reference signal (RS).

[0252] In the case of a beamforming system to which (analog) beamforming is applied, it is necessary to determine a DL transmit (Tx) / receive (Rx) beam pair for DL ​​RS transmission / reception and a UL Tx / Rx beam pair for transmission / reception of UCI (uplink control information: e.g., CSI, ACK / NACK).

[0253] The process of determining a DL beam pair may include: step (1), the eNB sends DL RSs corresponding to multiple TRP Tx beams to the UE; a TRP Tx beam selection step (2), at which the UE selects and / or reports one of the multiple TRP Tx beams; step (3), the eNB repeatedly sends the same RS signal corresponding to each TRP Tx beam; and step (4), the UE selects a UE Rx beam by measuring different UE Rx beams for the repeatedly transmitted signal.

[0254] In addition, the process of determining the UL beam pair includes: step (1), where the UE sends UL RS corresponding to multiple UE Tx beams to the eNB; a UE Tx beam selection step (2), at which the eNB selects and / or signals one of the multiple UE Tx beams; step (3), at which the UE repeatedly sends the same RS signal corresponding to each UE Tx beam to the eNB; and step (4), at which the eNB selects a TRP Rx beam by measuring different TRP Rx beams for the repeatedly transmitted signals.

[0255] When DL / UL beam reciprocity (or beam correspondence) is satisfied, that is, when it can be assumed that the eNB DL Tx beam and the eNB UL Rx beam are consistent with each other and the UE UL Tx beam and the UE DL Rx beam are consistent with each other in communication between the eNB and the UE, if one of the DL beam pair and the UL beam pair is determined, the process of determining the other can be omitted.

[0256] The process of determining DL and / or UL beam pairs may be performed periodically or aperiodically.

[0257] In the case where there are a large number of candidate beams, the required RS overhead may be large, and therefore, it is undesirable to frequently perform the process of determining DL and / or UL beam pairs.

[0258] It is assumed that the UE periodically performs SP (semi-persistent) CSI reporting after completing the process of DL / UL beam pair.

[0259] Here, the CSI-RS beam including a single antenna port or multiple antenna ports for CSI measurement by the UE can be formed into a TRP Tx beam determined as a DL beam and then transmitted, and the transmission period of the CSI-RS can be equal to the CSI reporting period, or can be transmitted more frequently.

[0260] Alternatively, the UE may transmit aperiodic CSI-RS more frequently according to the CSI reporting period.

[0261] The terminal (eg, UE) may periodically transmit measured CSI information as a predetermined UL Tx in the process of determining a UL beam pair.

[0262] When DL / UL beam management is performed, beam mismatch may occur depending on the set beam management period.

[0263] In particular, the optimal DL / UL beam pair can be changed when the UE moves in a position where the UE is rotated, or the radio channel environment changes due to the movement of objects around the UE (for example, the radio channel environment changes from a line-of-sight (LoS) environment to a non-LoS environment because the beam is blocked).

[0264] This change can be described as a beam failure event, which occurs when the beam management process executed by the network command fails to track.

[0265] Whether a beam failure event occurs can be determined by the UE through the reception quality of the DL RS, and a report message about this situation or a message for requesting beam restoration (hereinafter referred to as a "beam restoration request message") should be sent from the UE.

[0266] The beam recovery request message can be expressed in various ways, for example, a beam failure recovery request message, a control signal, a control message, a first message, etc.

[0267] After receiving the beam restoration request message from the UE, the eNB performs beam restoration through various procedures, such as transmitting a beam RS to the UE and requesting a beam report.

[0268] The above series of beam recovery processes are called "beam recovery"

[0269] In 3GPP, a new communication system called New Radio or New Rat (NR) is being standardized, and the following description is included in terms of beam management.

[0270] (Description 1)

[0271] NR supports the ability for the UE to trigger a mechanism to recover from beam failure.

[0272] For recovery purposes, the network explicitly configures resources for UL transmission of signals.

[0273] Supports configuration of resources (e.g., random access regions) on which the eNB listens in all or some directions.

[0274] (To be discussed later) Regarding the conditions for UE operation triggering resumption of signal RS / control channel / data channel monitoring.

[0275] Supports DL signals that allow the UE to monitor beams in order to identify new potential beams.

[0276] The transmission of beam scanning control channels is not excluded (to be discussed later).

[0277] This mechanism should consider the trade-off between performance and DL signaling overhead.

[0278] (Description 2)

[0279] The delayed beam management overhead should be considered in the design of CSI-RS for NR beam management, considering the following possible candidate solutions.

[0280] Option 1. IFDMA

[0281] Option 2. Large subcarrier spacing

[0282] Other aspects to consider in designing CSI-RS for NR beam management include, for example, CSI-RS multiplexing, UE beam switching delay, UE implementation complexity (e.g., AGC training time), CRS-RS coverage, etc.

[0283] (Description 3)

[0284] CSI-RS supports DL Tx beam scanning and UE Rx beam scanning.

[0285] NR CSI-RS supports the following mapping structures.

[0286] A NP CSI-RS port may be mapped for each (sub) time unit.

[0287] The same CSI-RS antenna port may be mapped on a (sub)time unit.

[0288] Here, "time unit" indicates n>=1 OFDM symbol in the configuration / reference parameter set.

[0289] Each time unit can be divided into sub-time units.

[0290] Such a mapping structure can be used to support multiple panels / Tx chains.

[0291] (Option 1)

[0292] The Tx beams are the same across time units.

[0293] The Tx beams across time units are different.

[0294] (Option 2)

[0295] The Tx beam is different in each time unit.

[0296] The Tx beams are the same across time units.

[0297] (Option 3): A combination of Option 1 and Option 2

[0298] Within a time unit, the Tx beams across sub-time units are the same.

[0299] In another time unit, the Tx beam of each sub-time unit is different.

[0300] Hereinafter, a beam failure recovery mechanism of a UE with respect to the method proposed in this specification will be briefly described.

[0301] The UE's beam failure recovery mechanism includes the following processes (1) to (4).

[0302] (1) Detection beam failure

[0303] (2) Identifying new candidate beams

[0304] (3) Sending beam failure recovery request

[0305] (4) The UE monitors the gNB’s response to the beam failure recovery request.

[0306] First, in the process of detecting beam failure, the UE monitors the beam failure detection RS to check whether the beam failure triggering condition is met.

[0307] The beam failure detection RS includes at least a periodic CSI-RS for beam management. Here, a synchronization signal (SS) block can also be used for beam management, and when the SS block is used for beam management, the SS block in the service call can be considered.

[0308] Here, the SS block may be interpreted as allowing the SS to be transmitted in slot units or specific time units.

[0309] Here, beam failure detection RS may include not only the case of measuring the quality of the corresponding RS, but also the case of measuring the detection / demodulation quality of the associated radio channel using the corresponding RS and the quasi co-location (QCL) indicator. For example, the CSI-RS or SS block-related ID indicated for (primary) PDCCH monitoring may be understood as a beam failure detection RS, and in this case, whether a beam failure event occurs may be defined as a case where the detection / demodulation performance of the corresponding PDCCH is equal to or lower than a preset level.

[0310] A beam failure event may occur when the quality of the beam-pair link of the associated control channel drops to a preset level or lower.

[0311] Specifically, the quality of the beam-pair link of the associated control channel may be determined through PDCCH detection performance.

[0312] For example, in the process of UE monitoring PDCCH (or blind decoding), when the PDCCH detection performance is poor according to the result of CRC check, the UE can detect beam failure.

[0313] Alternatively, in the case where multiple PDCCHs are transmitted through multiple beams (or multiple PDCCHs are transmitted through different beams), whether a beam failure event occurs may be determined by the detection performance of a specific PDCCH (e.g., a serving beam and associated PDCCH).

[0314] Here, each of the plurality of PDCCHs may be transmitted and / or received for a different beam through a different control channel (eg, symbol, slot, subframe, etc.).

[0315] In this case, the control channel region of each beam may be predefined, or the control channel region may be transmitted and received through higher layer signaling.

[0316] In addition, in the case where whether a beam failure event occurs is determined by the quality of the beam pair link of the associated control channel, whether a beam failure event occurs can be determined based on whether the quality of the DL beam is reduced to a preset level or lower, or whether the quality of the UL beam is reduced to a preset level or lower, or whether the quality of both the DL beam and the UL beam is reduced to a preset level or lower.

[0317] Here, being below a preset level may mean being below a preset value, having an associated timer timed out, or the like.

[0318] In addition, as a signal for detecting beam failure, BRS, RS for fine timing / frequency tracking, SS block, DM-RS for PDCCH, DM-RS for PDSCH, etc. can be used.

[0319] Next, in the process of identifying new candidate beams, the UE discovers new candidate beams by monitoring the beam identification RS.

[0320] The beam identification RS may include 1) a periodic CSI-RS for beam management when the beam identification RS is configured by the NW, and may include information about the periodic CSI-RS and the SS block in the serving cell when the SS block is used for beam management.

[0321] Next, in the process of sending a beam failure recovery request, the information transmitted in the beam failure recovery request includes at least one of the following: 1) explicit / implicit information for identifying the UE and new gNB TX beam information; or 2) explicit / implicit information about whether there is a new candidate beam after identifying the UE.

[0322] In addition, the transmission of the beam failure recovery request can select one of PRACH, PUCCH and PRACH-like (for example, parameters for preamble sequences different from PRACH).

[0323] -Beam failure recovery request resources / signals may be used additionally in scheduling requests.

[0324] Next, the UE monitors the channel search space to receive the gNB’s response to the beam failure recovery request.

[0325] In addition, regarding the transmission of beam failure recovery request, the following conditions are supported.

[0326] -Condition: Detecting beam failure and identifying the failed beam when only CSI-RS is used to identify new candidate beams

[0327] In addition, the following channels are supported for sending beam failure recovery requests.

[0328] - For a PRACH-based non-contention-based channel, FDM is used at resources that are orthogonal to resources used for transmission of at least a different PRACH.

[0329] Supports PUCCH for transmitting beam failure recovery requests.

[0330] As described above, in the case of NR, the beam restoration request message can support (1) a (first) mechanism in which the beam restoration request message is sent using the same symbols as PRACH, and (2) a (second) mechanism in which the beam restoration request message is sent using symbols other than PRACH.

[0331] The first mechanism may be a useful mechanism when uplink synchronization is lost due to beam failure (when the beam quality is relatively significantly degraded or when there is no replacement beam) and / or when the timing of the beam failure event and the preset PRACH resource are close to each other in time.

[0332] The second mechanism may be a useful mechanism when beam failure or uplink synchronization is not lost (when beam quality is degraded relatively little or when there is any replacement beam), and / or when the timing of the beam failure event and the preset PRACH resources are far apart in time from each other, so that fast beam recovery is difficult to wait for PRACH resources (e.g., symbols).

[0333] In addition, upon beam failure, the UE may send a beam failure request message to the eNB a predetermined number of times, and when no response to the request is received from the eNB, the UE may perform a radio link failure (RLF).

[0334] Hereinafter, a method for restoring a beam when a beam failure occurs due to movement of a UE, proposed in this specification, will be described.

[0335] In particular, in this specification, a method for restoring a beam may be performed according to whether a replacement beam exists, and a detailed description thereof will be provided later.

[0336] A Beam RS (Reference Signal) (BRS) used in this specification is a DL physical signal for beam management, and a CSI-RS, a Mobile RS (MRS), a synchronization signal, etc. can be used as the Beam RS.

[0337] The beam RS can be set through resource settings (as an RRC layer) on the beam management framework (or CSI framework). That is, the beam RS can be preset through resource settings.

[0338] As described below, the beam management frame is a structure showing associated relationships beam report settings, beam resource settings, beam resource sets, and measurement settings. A further detailed description thereof will be provided later.

[0339] In addition, the beam report used in this specification indicates beam-related feedback information of the UE and may include information related to beam quality and / or beam indication information.

[0340] “A and / or B,” “A and / or B,” and “A / B” in this specification may be interpreted as being the same as the expression “including at least one of A or B.”

[0341] The information related to the beam quality may be channel quality information (CQI), layer 3 reference signal received power (RSRP), layer 1 RSRP, etc.

[0342] In addition, the beam indication information can be a CSI-RS resource indicator (CRI), a precoding matrix indicator (PMI), an RS port index, etc.

[0343] Beam-related feedback information, parameters, reporting period, frequency unit (granularity (e.g., wideband feedback, subband feedback), etc.) can be set through report settings (as RRC layer messages) on the beam management frame (or CSI frame).

[0344] That is, beam-related feedback information, reporting frequency units, etc. can be pre-set through report settings.

[0345] When the UE sends a beam restoration request to the network (e.g., eNB), the network may perform the following two operations (method 1 and method 2).

[0346] (Method 1)

[0347] Method 1 indicates network operation in the absence of a replacement beam (eg, a replacement DL beam pair).

[0348] That is, method 1 relates to a method for sending a (non-periodic) beam RS (or triggered beam RS) and sending a (non-periodic) beam report trigger to the UE when the network receives a beam recovery request from the UE.

[0349] The replacement beam can be understood as an RS set set by the eNB for periodic beam management or monitoring, and can be provided in a number equal to or smaller than the number of beam sets that the UE can measure.

[0350] That is, the replacement beam may be an RS having a specific quality among the RSs set for beam management.

[0351] For example, the network may configure N CSI-RS resources for periodic beam management or monitoring of the UE.

[0352] However, the UE can measure the signal quality not only from the N CSI-RS resources, but also from the M beamformed SS blocks (with wider coverage). Therefore, a UE may not be able to find a replacement beam from the N CSIRS, and may be able to find a replacement beam from the M SS blocks, i.e., a signal with a certain quality or higher. However, in this case, because the SS blocks are cell-specific and periodic, the SS blocks are not suitable for being included in the scope of the above-mentioned (non-periodic) beam RS that must be sent UE-specifically on demand. Therefore, in this case, although there is a replacement SS block beam, it can be considered that the subsequent process for sending (non-periodic) beam RS (e.g., CSI-RS) to the UE falls within the scope of method 1.

[0353] Figure 10 An example of network operation according to whether or not a replacement beam proposed by this specification exists is shown.

[0354] Specifically, Figure 10 The upper part is a diagram showing method 1 proposed in this specification.

[0355] Here, the beam RS trigger and the beam report trigger may be sent by signal or may be sent jointly by signal.

[0356] For example, the network can use one DCI to trigger beam RS and beam reporting together.

[0357] refer to Figure 10 On top of , the network sends (periodic) beam RS to DL.

[0358] Next, when the network receives a beam restoration request from the UE, the network jointly triggers (aperiodic) beam RS and (aperiodic) beam reporting to the UE (according to method 1).

[0359] Therefore, the UE performs beam measurement through the reference resource and reports the result of the beam measurement to the network.

[0360] A specific method for determining the reference resource will be described later.

[0361] (Method 2)

[0362] Method 2 shows the network operation when there are alternative DL beam pairs.

[0363] That is, in method 2, when the network receives a beam recovery request from the UE, the network performs (non-periodic) beam report triggering, such as Figure 10 shown in the lower part of .

[0364] Figure 10The lower part is a diagram showing method 2 proposed in this specification.

[0365] refer to Figure 10 In the lower part, the network sends (periodic) beam RS to DL.

[0366] Then, when the network receives a beam restoration request from the UE, the network triggers (aperiodic) reporting of the beam to the UE.

[0367] Here, in method 2, unlike method 1, since the UE knows the replacement beam pair, the network does not additionally send (or does not trigger) a (non-periodic) beam RS to the corresponding UE.

[0368] Therefore, the UE performs beam measurement through the reference resource and reports the result of the beam measurement to the network.

[0369] Here, the preferred Tx beam indicator and beam quality metric may be sent together in the beam reporting process.

[0370] As described above, in Method 2, when the UE knows information about the DL Tx beam (or DL ​​beam pair) to replace from the channel measured by the preset RS, beam RS transmission by the network and beam RS reception by the UE can be omitted, and therefore Method 2 is a useful method.

[0371] In contrast, the above-mentioned method 1 is a method useful when there is no replacement beam or when the eNB cannot know whether there is a replacement beam.

[0372] Additionally, regarding Method 1 and Method 2, the (beam) reporting settings may not be differentiated.

[0373] That is, in Method 1 and Method 2, beam reporting can be configured with the same feedback information, have the same time domain behavior (e.g., non-periodic reporting), and have the same frequency granularity.

[0374] The same feedback information may include, for example, a preferred DL Tx beam indicator and a beam quality metric.

[0375] The preferred DL Tx beam indicator may be, for example, a beam ID, a CSI resource indicator (CRI), an RS port index, etc.

[0376] The beam quality metric may be, for example, L1 RSRP, CQI, etc.

[0377] In the beam recovery method proposed in this specification, the network can support at least one setting method for the UE through RRC signaling.

[0378] Figure 11is a diagram illustrating an example of a beam correlation configuration method to which the method proposed in this specification can be applied.

[0379] (Setting method 1)

[0380] refer to Figure 11 (a), the reporting setting may include an aperiodic CSI / beam reporting setting, and the resource setting may include an aperiodic beam RS setting (e.g., CSI-RS) and a periodic / semi-persistent beam RS setting.

[0381] Here, a plurality of report settings may be represented as report settings, and a plurality of resource settings may be represented as resource settings.

[0382] Additionally, a resource setup may include one or more resource sets.

[0383] refer to Figure 11 As shown in (a), in the measurement setting, one report setting and two resource settings are connected via links (or channels), respectively.

[0384] (Setting method 2)

[0385] refer to Figure 11 (b), as described below, the reporting setting includes an aperiodic CSI / beam reporting setting, the resource setting includes a beam RS setting, and the beam RS setting includes at least two resource sets.

[0386] – Resource sets with aperiodic RS (e.g., CSI-RS)

[0387] - Resource sets with periodic / semi-persistent beam RS (e.g., CSI-RS)

[0388] Additionally, two settings (reporting settings and resource settings) are connected to one link (or channel) in the measurement settings.

[0389] As described above, setting method 1 is useful when time domain behaviors (aperiodic, semi-persistent (SP), periodic) are collectively set based on a resource setting unit.

[0390] Additionally, setting method 2 may be useful when time domain behaviors are collectively set based on resource setting units within resource settings.

[0391] Then, a method of providing information about whether the UE prefers one of Method 1 and Method 2, or whether there is an alternative beam (or whether there is measurement) to the network (or eNB) from the pre-measured RS will be described in detail.

[0392] Information about which method the UE prefers to use to transmit to the network or information about whether there is an alternative beam will be referred to as "control information" hereinafter.

[0393] Here, the control information may be included in a beam restoration signal or a beam failure report signal.

[0394] The control information can be an indicator or indication information directly indicating whether a replacement beam exists, preferred link information associated with a preconfigured non-periodic beam reporting setting (in the case of setting method 1), preferred resource setting information (in the case of setting method 1) or preferred resource set information (in the case of setting method 2).

[0395] The control information may be transmitted to the network as physical layer control information such as uplink control information (UCI) in the LTE system, and may be transmitted in the form of a higher layer message (eg, MAC CE).

[0396] In particular, the UE may use the same resources (eg, symbols) of the PRACH to transmit control information.

[0397] When the UE uses (or transmits) a signal code division multiplexed (CDM) or frequency division multiplexed (FDM) with a PRACH as a beam recovery signal, a sequence set to be used in the PRACH may be divided and used according to whether an alternative beam exists.

[0398] For example, when a sequence set to be used in PRACH is divided and used, separate root indexes or cyclic shift values ​​may be used.

[0399] Alternatively, when the UE uses a signal code division multiplexed (CDM) or frequency division multiplexed (FDM) with the PRACH as a beam restoration request signal, the same sequence set as that used in the PRACH can be used. However, in this case, different time / frequency domain orthogonal cover codes (OCCs) can be applied to identify whether the signal is a PRACH or a beam restoration request.

[0400] In addition, when indicating the aperiodic reporting trigger to the UE as a MAC control element (CE) which is a higher layer message and downlink control information (CD) which is a physical layer message, the network (or eNB) may include at least one of the following information (1) to (4).

[0401] (1) Information about valid / invalid links in pre-association settings (in the case of method 1)

[0402] : The UE performs beam measurement and beam reporting of the beam measurement by determining as a reference source only the RS included in the resource setting indicated as a valid link (or not indicated as an invalid link) among multiple resource settings pre-associated as measurement settings.

[0403] (2) Information on valid / invalid resource settings in pre-association settings (in the case of setting method 2).

[0404] : The UE performs beam measurement and beam reporting by determining as a reference source only the RS included in the valid resource settings (or not indicated as invalid resource settings) among multiple resource settings pre-associated as measurement settings.

[0405] (3) Information on valid / invalid resource sets within the pre-association resource setting (in the case of setting method 2).

[0406] : The UE performs beam measurement and beam reporting by determining only the RS included in the valid resource set among the resource sets pre-associated as measurement settings as reference sources.

[0407] (4) Report type / mode setting method (applicable to both setting method 1 and setting method 2)

[0408] : The report type / mode setting information indicates an indicator or indication information as to whether the triggering of the aperiodic resource is jointly indicated together with the triggering of the aperiodic report or whether only the aperiodic report is triggered.

[0409] Here, when the triggering of non-periodic resources and the triggering of non-periodic reports are jointly indicated, the reporting type or mode can be expressed as a joint triggering mode or a first mode, and when only the triggering of non-periodic reports is indicated, the reporting type or mode can be expressed as a reporting-only triggering mode or a second mode.

[0410] In the joint triggering mode (or first mode), the UE performs beam measurement and beam reporting by determining only the resource setting configured by RRC (setting method 1) or the non-periodic resource setting / resource set in the resource setting (setting method 2) as the reference resource.

[0411] That is, the UE ignores the periodic resources / semi-persistent resources connected to the aperiodic report.

[0412] In addition, in the report-only trigger mode (or second mode), the UE performs beam measurement and beam reporting by determining only the periodic or semi-persistent resource settings / resource sets from the RRC configured resource settings (setting method 1) and resource sets (setting method 2) as the reference source.

[0413] That is, the UE ignores the aperiodic resources connected to the aperiodic report.

[0414] In addition, when the UE reports to the eNB information about which of method 1 and method 2 is preferred or whether there is a replacement beam from a pre-measured RS (or whether there is a measurement), the eNB can send information (acknowledgement message or ACK / NACK) to the UE indicating whether the UE's reported information is applied.

[0415] When the UE's report information is sent to the eNB before the above-mentioned aperiodic report trigger is indicated for the eNB, information on whether to apply the UE's report information may be sent together with the above-mentioned information (1) to (4) when the aperiodic report trigger is indicated.

[0416] When the UE reports to the eNB information about which of Method 1 and Method 2 is preferred or information about whether there is a replacement beam from the pre-measured RS (or whether there is measurement), the eNB can send information to the UE to confirm the reception and application of the corresponding information.

[0417] For example, when the eNB sends an acknowledgement (or ACK) message to the UE, it means that the eNB confirms the application of the information sent by the UE.

[0418] Alternatively, when the eNB does not send a confirmation message or sends a non-confirmation (or NACK) message to the UE, the eNB may request the UE to additionally send some of the above information (1) to 4) or may request the UE to resend information about which of method 1 and method 2 is preferred or information about whether there is a replacement beam (or whether there is a measurement).

[0419] As described above, information on which of Method 1 and Method 2 is preferred or information on whether there is an alternative beam (or whether there is measurement) may be referred to as "control information."

[0420] In addition, when information about which of Method 1 and Method 2 is preferred or information about whether there is a replacement beam (or whether there is measurement) is reported (in advance) to the eNB, the above information (1) to (4) can be omitted.

[0421] Next, a method for determining (or deciding) a reference resource for beam measurement and beam reporting will be described.

[0422] The UE explicitly or implicitly reports to the eNB through a beam restoration request signal (or a beam failure report signal) information about measurements indicating (i) the presence of an alternative beam (or information indicating that method 2 is preferred).

[0423] Next, when the eNB instructs the UE to perform aperiodic beam report triggering (within a specific time or before the expiration of a specific timer), the UE can determine the resources activated (or triggered or configured) before the time slot of receiving the report triggering message from the resource setting associated with the corresponding aperiodic beam report (setting method 1) and the resources (RS) included in the resource set (setting method 2) as reference resources, and can then perform beam measurement and beam reporting.

[0424] That is, the reference resource is determined to be a specific resource that is activated before the report triggering message is received.

[0425] For a description thereof, reference is made to the accompanying drawings relating to method 2 .

[0426] As another example, the UE explicitly or implicitly reports to the eNB through a beam recovery request signal (or a beam failure report signal) information indicating (ii) that there is no measurement on the replacement beam (or information indicating that method 1 is preferred).

[0427] Next, when the eNB instructs the UE to perform aperiodic beam report triggering (within a specific time or before the expiration of a specific timer), the UE can determine the resource to be activated (or triggered or configured) at the timing of the same time slot as the time slot in which the report triggering message is received (for example, the triggered / activated aperiodic RS in a later time slot) from the resource setting associated with the corresponding aperiodic beam report (setting method 1) and the resources (RS) included in the resource set (setting method 2) as the reference resource, and can then perform beam measurement and beam reporting.

[0428] That is, the reference resource may be determined as a specific resource to be activated in the same time slot as the time slot in which the report trigger message is received or in a time slot after the report trigger message is received.

[0429] Figure 12 is a flowchart illustrating a method for performing beam recovery proposed in this specification.

[0430] First, the UE receives a beam reference signal (BRS) for beam management from the eNB ( S1210 ).

[0431] Next, when the UE detects a beam failure event, the UE transmits a control signal for a beam failure recovery request to the eNB (S1220).

[0432] A beam failure event may be detected based on the received BRS.

[0433] The control signal includes indication information indicating that the replacement beam exists.

[0434] As described above, the replacement beam may refer to a reference signal having a channel quality greater than a specific channel quality among reference signals configured for beam management.

[0435] Next, when beam reporting is triggered, the UE reports beam measurement results in specific resources to the eNB (S1230).

[0436] The control signal may use the same time resources of the Physical Random Access Channel (PRACH).

[0437] In this case, the control signal may be code division multiplexed (CDM) or frequency division multiplexed (FDM) with the PRACH in the time resource.

[0438] The control signal may be transmitted through a physical uplink control channel (PUCCH).

[0439] Depending on whether an alternative beam exists, the control signal may use different time and / or frequency resources, different sequence sets, and / or different uplink control information (UCI).

[0440] In this case, different sequence sets can be distinguished by root sequence index or cyclic shift value.

[0441] In addition, the indication information may be information about a preferred link associated with a preset non-periodic beam reporting setting, information about a preferred resource setting associated with a preset non-periodic beam reporting setting, or information about a preferred resource set associated with a preset non-periodic beam reporting setting.

[0442] In addition, the UE may receive indication information from the eNB indicating triggering of beam reporting.

[0443] Here, beam reporting can be triggered based on the indication message.

[0444] The indication message may include at least one of the following: information about valid or invalid links among the settings pre-associated as measurement settings, information about valid or invalid resource settings among the settings pre-associated as measurement settings, information about valid or invalid resource sets among the settings pre-associated as measurement settings, and beam reporting mode setting information.

[0445] A measurement setup may be one report setup and two resource setups connected by a link, or one report setup and one resource setup connected by a link.

[0446] The beam reporting mode setting information may indicate a first mode of jointly triggering aperiodic beam reference signal transmission and aperiodic beam reporting, or a second mode of only triggering aperiodic beam reporting.

[0447] The first mode indicates the above-mentioned joint trigger mode, and the second mode indicates the above-mentioned report-only trigger mode.

[0448] If the beam reporting mode setting information is set to the first mode, the specific resource may be an aperiodic resource setting or an aperiodic resource set from among resource settings or resource sets configured by radio resource control (RRC).

[0449] In this case, the specific resource may be a resource activated to enable beam measurement in the same time slot as the time slot in which the indication message is received or in a time slot after the indication message is received.

[0450] Alternatively, when the beam reporting mode setting information is set to the second mode, the specific resource may be a periodic or semi-persistent resource setting or resource set among the RRC-configured resource setting or resource set.

[0451] In this case, the specific resource may be a resource that is activated before the time slot in which the indication message is received to enable beam measurement.

[0452] Additionally, the UE may receive a response to the report from the eNB.

[0453] If the response is NACK, the UE may retransmit information including at least one of the indication information or information included in the indication message to the eNB.

[0454] General description of devices to which the present disclosure can be applied

[0455] Figure 13 An example of a block diagram of a wireless communication device according to an embodiment of the present disclosure is shown.

[0456] refer to Figure 13 , the wireless communication system includes an eNB (or network) 1310 and a UE 1320.

[0457] The eNB 1310 includes a processor 1311 , a memory 1312 , and a communication module 1313 .

[0458] Processor 1311 implements Figures 1 to 12 The functions, processes, and / or methods proposed in the present invention may be implemented by the processor 1311. The layers of the wired / wireless interface protocol may be implemented by the processor 1311. The memory 1312 is connected to the processor 1311 and stores various types of information for driving the processor 1311. The communication module 1313 is connected to the processor 1311 and transmits and / or receives wired / wireless signals.

[0459] The communication module 1313 may be a radio frequency (RF) unit for transmitting and receiving radio signals.

[0460] UE 1320 includes a processor 1321, a memory 1322, and a communication module (or RF unit) 1323. The processor 1321 is implemented in Figures 1 to 12 The functions, processes, and / or methods proposed in the present disclosure may be implemented by the processor 1321. The memory 1322 is connected to the processor 1321 and stores information related to the operation of the processor 1321. The communication module 1323 is connected to the processor 1321 and transmits and / or receives radio signals.

[0461] The memories 1312 and 1322 may be located inside or outside the processors 1311 and 1321 and may be connected to the processors 1311 and 1321 through various well-known means.

[0462] Furthermore, the eNB 1310 and / or the UE 1320 may have a single antenna or multiple antennas.

[0463] Figure 14 An example of a block diagram of a communication device according to an embodiment of the present disclosure is shown.

[0464] In particular, Figure 14 is shown in more detail Figure 13 Figure 1.

[0465] refer to Figure 14 , the UE includes a processor (or digital signal processor) 1410, an RF module (RF unit) 1435, a power management module 1405, an antenna 1440, a battery 1455, a display 1415, a keypad 1420, a memory 1430, a subscriber identity module (SIM) card 1425 (which may be optional), a speaker 1445, and a microphone 1450. The UE may include a single antenna or multiple antennas.

[0466] Processor 1410 may be configured to implement Figures 1 to 12 The functions, processes and / or methods proposed in the present disclosure may be implemented by the processor 1410.

[0467] The memory 1430 is connected to the processor 1410 and stores information related to the operation of the processor 1410. The memory 1430 may be located inside or outside the processor 1410 and may be connected to the processor 1410 through various well-known means.

[0468] For example, a user may input instruction information, such as a phone number, by pressing a button on keypad 1420 or by voice activation using microphone 1450. Processor 1410 receives and processes the instruction information to execute an appropriate function, such as dialing a phone number. Operational data may be retrieved from SIM card 1425 or memory 1430 to execute the function. In addition, processor 1410 may display the instruction and operation information on display 1415 for the user's reference and convenience.

[0469] The RF module 1435 is connected to the processor 1410 and transmits and / or receives RF signals. The processor 1410 issues instruction information to the RF module 1435 to initiate communication, for example, to transmit a radio signal containing voice communication data. The RF module 1435 includes a receiver and a transmitter to receive and transmit radio signals. The antenna 1440 facilitates the transmission and reception of radio signals. After receiving the radio signal, the RF module 1435 can forward the signal and convert it to baseband frequency for processing by the processor 1410. The processed signal is then converted into audible or readable information output via the speaker 1445.

[0470] The above-mentioned embodiments of the present disclosure are combinations of elements and features of the present disclosure. Unless otherwise stated, these elements or features may be considered as optional. Each element or feature may be practiced without being combined with other elements or features. In addition, the embodiments of the present disclosure may be constructed by combining a part of the elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some elements or features of any one embodiment may be included in another embodiment and may be replaced by corresponding elements or features of another embodiment. It is obvious to those skilled in the art that claims that are not explicitly referenced to each other in the appended claims may be presented in combination as embodiments of the present disclosure, or may be included as new claims by subsequent amendments after filing the application.

[0471] The embodiments of the present disclosure may be implemented in various ways, for example, hardware, firmware, software, or a combination thereof. In a hardware configuration, the embodiments of the present disclosure may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

[0472] In a firmware or software configuration, the embodiments of the present disclosure may be implemented in the form of modules, procedures, functions, etc. that perform the above-described functions or operations. The software code may be stored in a storage unit and executed by a processor. The storage unit may be located inside or outside the processor to send data to and receive data from the processor through various known means.

[0473] Those skilled in the art will understand that the present disclosure may be performed in other specific ways different from those set forth herein without departing from the spirit and essential features of the present disclosure. Therefore, the above embodiments are to be construed in all respects as illustrative and not restrictive. The scope of the present invention should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes that fall within the meaning and equivalent range of the appended claims should be included therein.

[0474] Industrial Applicability

[0475] The beam management method in wireless communication of the present disclosure has been described mainly with respect to examples applied to 3GPP LTE / LTE-A systems and 5G, but the method may be applied to other wireless communication systems.

Claims

1. A method for performing a beam failure detection and recovery process by a user equipment (UE) in a wireless communication system, the method comprising: Triggering beam failure recovery (BFR) based on beam failure detection; generating a BFR medium access control (MAC) control element (CE) based on the triggered BFR; and Sending the BFR MAC CE to the network in a physical uplink shared channel (PUSCH), The BFR MAC CE includes available indication information of candidate beams. The candidate beam available indication information may indicate whether candidate reference signal (RS) identification information is present in the BFR MAC CE, The candidate RS identification information indicates the index of the RS whose reference signal received power (RSRP) is higher than the threshold among the RSs in the RS set. The RS set includes at least one of a channel state information-reference signal (CSI-RS) or a synchronization signal block (SSB), and The aperiodic beam reporting is performed based on the report triggering information, and the report triggering information triggers the aperiodic beam reporting and the RS used for measurement together.

2. The method according to claim 1, in, The UE is provided with the RS set through information indicating at least one candidate beam RS.

3. The method according to claim 1, in, A downlink control information (DCI) format includes the report triggering information.

4. The method according to claim 1, in, The report triggering information indicates a resource set associated with measurement configuration information of radio resource control (RRC).

5. The method according to claim 4, in, The resource set is related to a report configuration.

6. The method according to claim 1, in, The aperiodic beam report includes an RS resource indicator and RSRP.

7. A user equipment (UE) for performing a beam failure detection and recovery process in a wireless communication system, the UE comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: Triggering beam failure recovery (BFR) based on beam failure detection; generating a BFR medium access control (MAC) control element (CE) based on the triggered BFR; and sending, by the at least one transceiver, the BFRMAC CE to a network in a physical uplink shared channel (PUSCH), The BFR MAC CE includes available indication information of candidate beams. The candidate beam available indication information may indicate whether candidate reference signal (RS) identification information is present in the BFR MAC CE, The candidate RS identification information indicates the index of the RS whose reference signal received power (RSRP) is higher than the threshold among the RSs in the RS set. The RS set includes at least one of a channel state information-reference signal (CSI-RS) or a synchronization signal block (SSB), and The aperiodic beam reporting is performed based on the report triggering information, and the report triggering information triggers the aperiodic beam reporting and the RS used for measurement together.

8. A base station (BS) for supporting beam failure recovery of a user equipment (UE) in a wireless communication system, the BS comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: transmitting, by the at least one transceiver, to the UE, information indicating a reference signal (RS) set related to at least one candidate beam; and receiving, by the at least one transceiver, a beam failure recovery (BFR) medium access control (MAC) control element (CE) from the UE in a physical uplink shared channel (PUSCH), the BFR MAC CE being triggered based on beam failure detection at the UE, The BFR MAC CE includes available indication information of candidate beams. The candidate beam available indication information may indicate whether candidate reference signal (RS) identification information is present in the BFR MAC CE, The candidate RS identification information indicates the index of the RS whose reference signal received power (RSRP) is higher than the threshold among the RSs in the RS set. The RS set includes at least one of a channel state information-reference signal (CSI-RS) or a synchronization signal block (SSB), and The aperiodic beam report is received from the UE based on report triggering information, and the report triggering information triggers the aperiodic beam report and the RS for measurement together.

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