Method for performing a channel access procedure and apparatus for the method

Abstract

The present disclosure discloses a method for transmitting an uplink signal by a user equipment in a wireless communication system. Specifically, the method includes the following features: receiving first information related to an uplink (UL) transmit beam; determining a listen-before-talk (LBT) beam based on the first information; and transmitting the uplink signal via the UL transmit beam based on the LBT according to the LBT beam having been successfully transmitted.

Description

Technical Field

[0001] The present disclosure relates to a method of performing a channel access procedure and an apparatus for the method, and more particularly, to a method of configuring a directional listen-before-talk (LBT) beam for performing LBT on a user equipment and an apparatus for the method. Background Art

[0002] As more and more communication devices require greater communication traffic in line with the current trend, the next generation, the 5th generation (5G) system is needed to provide enhanced wireless broadband communication compared to the traditional LTE system. In the next generation 5G system, communication scenarios are divided into enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), massive machine type communication (mMTC), etc.

[0003] In this article, eMBB is a next-generation mobile communication scenario characterized by high spectral efficiency, high user experience data rate and high peak data rate, URLLC is a next-generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency and ultra-high availability (for example, vehicle-to-everything (V2X), emergency services and remote control), and mMTC is a next-generation mobile communication scenario characterized by low cost, low energy, short packets and large-scale connections (for example, the Internet of Things (IoT)). Summary of the invention

[0004] Technical issues

[0005] An object of the present disclosure is to provide a method of performing a channel access procedure and an apparatus for the method.

[0006] Those skilled in the art will understand that the objects that can be achieved by the present disclosure are not limited to those specifically described above, and the above and other objects that can be achieved by the present disclosure will be more clearly understood from the following detailed description.

[0007] Technical Solution

[0008] According to an aspect of the present disclosure, a method for sending an uplink signal by a user equipment (UE) in a wireless communication system is provided, the method comprising the following steps: receiving first information related to an uplink (UL) transmit beam, determining a listen-before-talk (LBT) beam based on the first information, and sending the uplink signal through the UL transmit beam based on success of LBT performed according to the LBT beam.

[0009] The LBT beam may include the UL transmit beam.

[0010] The LBT beam may include the UL transmit beam based on receiving second information related to the LBT beam, and an area of ​​the LBT beam may be larger than an area of ​​the UL transmit beam.

[0011] Based on not receiving the second information related to the LBT beam, the LBT beam can be the same as the UL transmission beam.

[0012] The LBT beam may be re-determined based on M1 failures in performing LBT, where M1 is a positive integer.

[0013] The UL bandwidth part (BWP) may be switched based on failure M1 of performing LBT according to the re-determined LBT beam.

[0014] In another aspect of the present disclosure, a user equipment (UE) for transmitting an uplink signal in a wireless communication system is provided herein, the UE comprising: at least one transceiver; at least one processor; and at least one memory, the at least one memory being operatively connected to the at least one processor and configured to store instructions, the instructions causing the at least one processor to perform operations when executed. The operations include: receiving first information related to an uplink (UL) transmit beam through the at least one transceiver, determining a listen-before-talk (LBT) beam based on the first information, and transmitting the uplink signal through the UL transmit beam through the at least one transceiver based on success of LBT performed according to the LBT beam.

[0015] The LBT beam may include the UL transmit beam.

[0016] The LBT beam may include the UL transmit beam based on receiving second information related to the LBT beam, and an area of ​​the LBT beam may be greater than an area of ​​the UL transmit beam.

[0017] Based on not receiving the second information related to the LBT beam, the LBT beam can be the same as the UL transmission beam.

[0018] The LBT beam may be re-determined based on M1 failures in performing LBT, where M1 is a positive integer.

[0019] The UL bandwidth part (BWP) may be switched based on failure M1 of performing LBT according to the re-determined LBT beam.

[0020] In another aspect of the present disclosure, a device for transmitting an uplink signal in a wireless communication system is provided herein, the device comprising: at least one processor; and at least one memory, the at least one memory being operatively connected to the at least one processor and configured to store instructions, the instructions causing the at least one processor to perform operations when executed. The operations include: receiving first information related to an uplink (UL) transmit beam, determining a listen-before-talk (LBT) beam based on the first information, and transmitting the uplink signal through the UL transmit beam based on success of LBT performed according to the LBT beam.

[0021] In another aspect of the present disclosure, a computer-readable storage medium including at least one computer program is provided herein, the computer program causing at least one processor to perform operations. The operations include receiving first information related to an uplink (UL) transmit beam, determining a listen-before-talk (LBT) beam based on the first information, and transmitting an uplink signal through the UL transmit beam based on success of LBT performed according to the LBT beam.

[0022] In another aspect of the present disclosure, a method for receiving an uplink signal by a base station (BS) in a wireless communication system is provided herein, the method comprising the steps of: transmitting first information related to an uplink (UL) transmit beam, and receiving the uplink signal through the UL transmit beam. A listen-before-talk (LBT) beam for the UL signal may be determined based on the UL transmit beam.

[0023] In another aspect of the present disclosure, a base station (BS) for receiving an uplink signal in a wireless communication system is provided herein, the BS comprising: at least one transceiver; at least one processor; and at least one memory, the at least one memory being operatively connected to the at least one processor and configured to store instructions, the instructions causing the at least one processor to perform operations when executed. The operations include: transmitting first information related to an uplink (UL) transmit beam through the at least one transceiver, and receiving the uplink signal through the UL transmit beam through the at least one transceiver. A listen-before-talk (LBT) beam for the uplink signal may be determined based on the UL transmit beam.

[0024] Beneficial Effects

[0025] According to the present disclosure, a base station (BS) may effectively configure an LBT beam through which a user equipment (UE) will perform LBT according to a mode of the UE (eg, idle / inactive mode or connected mode).

[0026] The UE can perform efficient LBT according to the UE's mode using the LBT beam configured by the BS.

[0027] Those skilled in the art will understand that the effects that can be achieved by the present disclosure are not limited to the contents specifically described above, and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Physical channels in a 3rd Generation Partnership Project (3GPP) system as an exemplary wireless communication system and a general signal transmission method using the physical channels are shown.

[0029] Figure 2 , Figure 3 and Figure 4 is a diagram illustrating the structure of a radio frame and a time slot used in a New RAT (NR) system.

[0030] Figure 5 and Figure 6 is a diagram illustrating a configuration of a synchronization signal / physical broadcast channel (SS / PBCH) block and a method of transmitting the SS / PBCH block;

[0031] Figure 7 is a diagram illustrating an exemplary 4-step RACH procedure;

[0032] Figure 8 is a diagram illustrating an exemplary 2-step RACH procedure;

[0033] Fig. 9 is a diagram illustrating an exemplary contention-free RACH procedure;

[0034] Fig.10 and Fig.11 is a diagram illustrating transmission of a synchronization signal block (SSB) and a physical random access channel (PRACH) resource linked to the SSB;

[0035] Fig.12 An exemplary uplink (UL) transmission operation of a user equipment (UE) is illustrated;

[0036] Fig.13 An exemplary repeated transmission based on a configured grant is illustrated;

[0037] Fig.14 A wireless communication system supporting an unlicensed frequency band is illustrated;

[0038] Fig.15 An exemplary method of occupying resources in an unlicensed frequency band is illustrated;

[0039] Fig.16An exemplary channel access procedure of a UE for UL signal transmission and / or DL ​​signal transmission in an unlicensed band applicable to the present disclosure is illustrated;

[0040] Fig.17 is a diagram for illustrating a plurality of listen-before-talk sub-bands (LBT-SBs) applicable to the present disclosure;

[0041] Fig.18 is a diagram illustrating analog beamforming in an NR system;

[0042] Fig.19 is a diagram illustrating beam management in an NR system;

[0043] Fig. 20 and Fig.21 is a diagram for explaining a sounding reference signal (SRS) applicable to the present disclosure;

[0044] Fig. 22 is a diagram for explaining a beam-based LBT and a beam group-based LBT according to an embodiment of the present disclosure;

[0045] Fig.23 and Fig.24 is a diagram for explaining a problem that occurs while performing directional LBT (D-LBT) according to an embodiment of the present disclosure;

[0046] Figure 25 to Figure 27 is a diagram for explaining the overall operation process of a UE and a BS according to an embodiment of the present disclosure;

[0047] Fig.28 An exemplary communication system applicable to the present disclosure is illustrated;

[0048] Fig.29 An exemplary wireless device suitable for use with the present disclosure is illustrated; and

[0049] Fig.30 An exemplary vehicle or autonomous driving vehicle suitable for use with the present disclosure is illustrated. DETAILED DESCRIPTION

[0050] The following technologies may be used in various wireless access systems such as 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), etc. CDMA may be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented as a radio technology such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented as a radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wireless Fidelity (WiFi)), IEEE802.16 (Worldwide Interoperability for Microwave Access (WiMAX)), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA, and LTE-advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP New Radio or New Radio Access Technology (NR) is an evolved version of 3GPP LTE / LTE-A.

[0051] Although the following description is given in the context of a 3GPP communication system (e.g., NR) for the sake of clarity, the technical spirit of the present disclosure is not limited to the 3GPP communication system. For the background technology, terms and abbreviations used in the present disclosure, reference is made to the technical specifications (e.g., 38.211, 38.212, 38.213, 38.214, 38.300, 38.331, etc.) published before the present disclosure.

[0052] Hereinafter, 5G communication involving a new radio access technology (NR) system will be described.

[0053] The three key demand areas for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine type communications (mMTC), and (3) ultra-reliable low-latency communications (URLLC).

[0054] Some use cases may require multiple dimensions for optimization, while others may focus on just one key performance indicator (KPI). 5G supports these various use cases in a flexible and reliable manner.

[0055] eMBB goes far beyond basic mobile Internet access and covers rich interactive work, media and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers of 5G, and in the 5G era, we may not see dedicated voice services for the first time. In 5G, it is expected that voice will be processed as an application using only the data connectivity provided by the communication system. The main driving force for the increase in traffic is the increase in the size of content and the number of applications that require high data rates. As more and more devices are connected to the Internet, streaming services (audio and video), interactive video, and mobile Internet connections will continue to be more widely used. Many of these applications require always-on connectivity to push real-time information and notifications to users. Cloud storage and applications for mobile communication platforms are increasing rapidly. This applies to both work and entertainment. Cloud storage is a specific use case that drives the growth of uplink data rates. 5G will also be used for remote work in the cloud, and when this remote work is done with a tactile interface, much lower end-to-end latency is required to maintain a good user experience. Entertainment (e.g., cloud gaming and video streaming) is another key driver for increasing demand for mobile broadband capabilities. Entertainment will be essential on smartphones and tablets anywhere, including high mobility environments such as trains, cars and airplanes. Another use case is AR for entertainment and information search, which requires very little latency and a large amount of real-time data.

[0056] One of the most anticipated 5G use cases is the ability to actively connect embedded sensors in every field (i.e., mMTC). It is expected that there will be 20.4 billion potential Internet of Things (IoT) devices by 2020. In industrial IoT, 5G is one of the areas that will play a key role in enabling smart cities, asset tracking, smart utilities, agriculture, and secure infrastructure.

[0057] URLLC includes services that will revolutionize industries using ultra-reliable / available low-latency links such as remote control of critical infrastructure and autonomous vehicles. The levels of reliability and latency are critical for smart grid control, industrial automation, robotics, drone control and tuning, etc.

[0058] Now, multiple use cases in a 5G communication system including an NR system will be described in detail.

[0059] 5G can complement fiber to the home (FTTH) and cable-based broadband (or cable data service interface specification (DOCSIS)) as a means of delivering streaming data rates of hundreds of megabits per second to gigabits per second. Such high speeds are also needed for TV broadcasts with a resolution of 4K or higher (6K, 8K or higher) as well as virtual reality (VR) and AR. VR and AR applications mainly include immersive sports events. Specific applications may require special network configurations. For example, for VR games, gaming companies may have to integrate the network operator's core servers with edge network servers in order to minimize latency.

[0060] The automotive industry is expected to become a very important new driver of 5G in the case of many use cases for mobile communications for vehicles. For example, entertainment for passengers requires mobile broadband with both high capacity and high mobility, as future users will expect to continue their high-quality connection regardless of their location and speed. Other use cases in the automotive industry are AR dashboards. These dashboards will overlay information on what the driver is seeing through the front window, identify objects in the dark, and inform the driver of the distance and movement of objects. In the future, wireless modules will enable communication between the vehicles themselves, information exchange between the vehicle and the supporting infrastructure, and information exchange between the vehicle and other connected devices (e.g., devices carried by pedestrians). Safety systems can guide drivers to take alternative courses of action to enable them to drive more safely and reduce the risk of accidents. The next stage will be remotely controlled or autonomous vehicles. This requires very reliable and very fast communication between different autonomous vehicles and between vehicles and infrastructure. In the future, driverless vehicles will perform all driving activities, while the driver will focus on traffic anomalies that are difficult for the vehicle itself to detect. The technical requirements for autonomous vehicles require ultra-low latency and ultra-high reliability, thereby increasing traffic safety to a level that cannot be achieved by humans.

[0061] Smart cities and smart homes, often referred to as smart societies, will be embedded with dense wireless sensor networks. Distributed networks of smart sensors will identify cost and energy efficiency maintenance conditions for cities or homes. Similar settings can be made for each household, in which temperature sensors, window and heating controls, burglar alarms, and home appliances are all connected wirelessly. Many of these sensors are typically characterized by low data rates, low power, and low cost, but real-time high-definition (HD) video may be required in certain types of devices for monitoring, for example.

[0062] The consumption and distribution of energy, including heat or gas, is becoming highly decentralized, giving rise to the need for automatic control of very distributed sensor networks. Smart grids interconnect these sensors using digital information and communication technologies to collect and act on information. This information can include information about the behavior of suppliers and consumers, enabling smart grids to improve the efficiency, reliability, economic viability, and sustainability of the production and distribution of fuels such as electricity in an automated manner. Smart grids can be viewed as another sensor network with less latency.

[0063] The health sector has many applications that can benefit from mobile communications. Communication systems enable telemedicine, which provides clinical care at a distance. It helps to eliminate distance barriers and improve access to medical services, which are often not permanently available in remote rural communities. It is also used to save lives in critical care and emergency situations. Wireless sensor networks based on mobile communications can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0064] Wireless and mobile communications are becoming increasingly important for industrial applications. Wires are expensive to install and maintain, and the possibility of replacing cables with reconfigurable wireless links is an attractive opportunity for many industries. However, to achieve this, wireless connections need to operate with latency, reliability, and capacity similar to cables, and to simplify their management. Low latency and very low error probability are new requirements that 5G needs to address.

[0065] Finally, logistics and freight tracking are important use cases for mobile communications, i.e. enabling tracking of inventory and packages wherever they are located by using location-based information systems. Logistics and freight tracking use cases typically require lower data speeds, but require wider coverage and reliable location information.

[0066] Figure 1 Physical channels in a 3GPP system and a general signal transmission method using the physical channels are shown.

[0067] When the UE is powered on or enters a new cell, the UE performs an initial cell search (S11). The initial cell search involves acquiring synchronization with the BS. To this end, the UE receives a synchronization signal block (SSB) from the BS. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes its timing with the BS and obtains information such as a cell identifier (ID) based on the PSS / SSS. In addition, the UE can obtain information broadcast in the cell by receiving a PBCH from the BS. During the initial cell search, the UE can also monitor the DL channel status by receiving a downlink reference signal (DL RS).

[0068] After the initial cell search, the UE may acquire more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) corresponding to the PDCCH (S12).

[0069] Subsequently, in order to complete the connection with the BS, the UE may perform a random access procedure with the BS (S13 to S16). Specifically, the UE may send a preamble on a physical random access channel (PRACH) (S13), and may receive a PDCCH and a random access response (RAR) to the preamble on a PDSCH corresponding to the PDCCH (S14). The UE may then use the scheduling information in the RAR to send a physical uplink shared channel (PUSCH) (S15) and perform a contention resolution procedure, including receiving a PDCCH and a PDSCH signal corresponding to the PDCCH (S16).

[0070] When the random access procedure is performed in two steps, steps S13 and S15 may be performed as one step (wherein message A is transmitted by the UE), and steps S14 and S16 may be performed as one step (wherein message B is transmitted by the BS).

[0071] After the above process, in the general UL / DL signal transmission process, the UE may receive PDCCH and / or PDSCH from the BS (S17) and send a physical uplink shared channel (PUSCH) and / or a physical uplink control channel (PUCCH) to the BS (S18). The control information sent by the UE to the BS is generally referred to as uplink control information (UCI). UCI includes hybrid automatic repeat request acknowledgment / negative acknowledgment (HARQ-ACK / NACK), scheduling request (SR), channel state information (CSI), etc. CSI includes channel quality indicator (CQI), precoding matrix index (PMI), rank indication (RI), etc. Typically, UCI is sent on PUCCH. However, if control information and data should be sent simultaneously, the control information and data may be sent on PUSCH. In addition, the UE may send UCI aperiodically on PUSCH when receiving a request / command from the network.

[0072] Figure 2 Shows the radio frame structure.

[0073] In NR, UL and DL transmissions are configured on a frame basis. Each radio frame has a length of 10 ms and is divided into two 5-ms half frames. Each half frame is divided into five 1-ms subframes. A subframe is divided into one or more time slots, and the number of time slots in a subframe depends on the subcarrier spacing (SCS). Depending on the cyclic prefix (CP), each time slot includes 12 or 14 OFDM (A) symbols. When a normal CP is used, each time slot includes 14 OFDM symbols. When an extended CP is used, each time slot includes 12 OFDM symbols. Symbols may include OFDM symbols (or CP-OFDM symbols) and SC-FDMA symbols (or discrete Fourier transform-extended-OFDM (DFT-s-OFDM) symbols).

[0074] Table 1 exemplarily shows that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to the SCS in the normal CP case.

[0075] [Table 1]

[0076] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 15KHz(u=0) 14 10 1 30KHz(u=1) 14 20 2 60KHz(u=2) 14 40 4 120KHz(u=3) 14 80 8 240KHz(u=4) 14 160 16

[0077] *N slot symb : The number of symbols in a time slot; *N frame,u slot : Number of time slots in a frame; *N subframe,u slot : Number of time slots in a subframe

[0078] Table 2 shows that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCS in the case of extended CP.

[0079] [Table 2]

[0080] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 60KHz(u=2) 12 40 4

[0081] This frame structure is only an example, and the number of subframes, the number of time slots, and the number of symbols in a frame can be changed in various ways. In the NR system, different OFDM (A) parameter sets (e.g., SCS, CP length, etc.) can be configured for multiple cells aggregated for one UE. Therefore, the (absolute time) duration of a time resource (e.g., a subframe, a time slot, or a transmission time interval (TTI)) (for convenience, referred to as a time unit (TU)) consisting of the same number of symbols can be configured differently between the aggregated cells. In NR, various parameter sets (or SCSs) can be supported to support various fifth generation (5G) services. For example, with an SCS of 15kHz, a wide area in a traditional cellular band can be supported, while with an SCS of 30kHz or 60kHz, dense urban areas, less waiting time, and a wide carrier bandwidth can be supported. With an SCS of 60kHz or higher, a bandwidth greater than 24.25kHz can be supported to overcome phase noise.

[0082] The NR band may be defined by two types of frequency ranges FR1 and FR2. FR1 and FR2 may be configured as described in Table 3 below. FR2 may be millimeter wave (mmW).

[0083] [Table 3]

[0084] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz–7125MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0085] Figure 3 A resource grid is shown during the duration of a time slot. A time slot includes multiple symbols in the time domain. For example, a time slot includes 14 symbols in the normal CP case and 12 symbols in the extended CP case. A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) may be defined by multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) may be defined by multiple consecutive (physical) RBs ((P)RBs) in the frequency domain and corresponds to a parameter set (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., five) BWPs. Data communication may be performed in an active BWP, and only one BWP may be enabled for a UE. Each element in the resource grid may be referred to as a resource element (RE), to which a complex symbol may be mapped. Figure 4 An exemplary mapping of physical channels in time slots is shown.

[0086] DL control channel, DL or UL data and UL control channel can all be included in one time slot. For example, the first N symbols in the time slot (hereinafter referred to as the DL control area) can be used to send the DL control channel, and the last M symbols in the time slot (hereinafter referred to as the UL control area) can be used to send the UL control channel. N and M are integers equal to or greater than 0. The resource area (hereinafter referred to as the data area) between the DL control area and the UL control area can be used for DL ​​data transmission or UL data transmission. A time gap for DL ​​to UL or UL to DL switching can be defined between the control area and the data area. PDCCH can be sent in the DL control area, and PDSCH can be sent in the DL data area. Some symbols when switching from DL to UL in a time slot can be configured as time gaps.

[0087] Now, a detailed description will be given of physical channels.

[0088] DL channel structure

[0089] The eNB transmits a relevant signal to the UE on a DL channel described later, and the UE receives a relevant signal from the eNB on the DL channel.

[0090] (1) Physical Downlink Shared Channel (PDSCH)

[0091] PDSCH carries DL data (e.g., DL shared channel transport block (DL-SCH TB)) and adopts modulation schemes such as quadrature phase shift keying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64-ary QAM (64QAM) or 256-ary QAM (256QAM). TB is encoded as a codeword. PDSCH can transmit up to two codewords. The codewords undergo scrambling and modulation mapping independently, and the modulation symbols from each codeword are mapped to one or more layers. An OFDM signal is generated by mapping each layer to a resource together with a DMRS, and the OFDM signal is sent through a corresponding antenna port.

[0092] (2) Physical Downlink Control Channel (PDCCH)

[0093] PDCCH transmits DCI. For example, PDCCH (i.e., DCI) may carry information about the transmission format and resource allocation of the DL shared channel (DL-SCH), resource allocation information of the uplink shared channel (UL-SCH), paging information about the paging channel (PCH), system information about DL-SCH, information about resource allocation of high-level control messages (e.g., RAR sent on PDSCH), transmit power control commands, information about the activation / release of the configured scheduling, etc. DCI includes a cyclic redundancy check (CRC). The CRC is masked using various identifiers (IDs) (e.g., radio network temporary identifier (RNTI)) according to the owner or purpose of the PDCCH. For example, if the PDCCH is used for a specific UE, the CRC is masked by the UE ID (e.g., cell-RNTI (C-RNTI)). If the PDCCH is used for a paging message, the CRC is masked by the paging-RNTI (P-RNTI). If the PDCCH is for system information (eg, system information block (SIB)), the CRC is masked by a system information RNTI (SI-RNTI). When the PDCCH is for RAR, the CRC is masked by a random access-RNTI (RA-RNTI).

[0094] PDCCH uses a fixed modulation scheme (e.g., QPSK). One PDCCH includes 1, 2, 4, 8, or 16 control channel elements (CCEs) depending on its aggregation level (AL). One CCE includes 6 resource element groups (REGs), each REG being defined by one OFDM symbol x one (P)RB.

[0095] The PDCCH is sent in a control resource set (CORESET). A CORESET corresponds to a set of physical resources / parameters used to transmit PDCCH / DCI in a BWP. For example, a CORESET is defined as a set of REGs with a given set of parameters (e.g., SCS, CP length, etc.). A CORESET may be configured by system information (e.g., a master information block (MIB)) or UE-specific high-level signaling (e.g., RRC signaling). For example, the following parameters / information may be used to configure a CORESET, and multiple CORESETs may overlap with each other in the time / frequency domain.

[0096] -controlResourceSetId: indicates the ID of the CORESET.

[0097] -frequencyDomainResources: Indicates the frequency domain resources of the CORESET. The frequency domain resources are indicated by a bitmap, and each bit of the bitmap corresponds to an RB group (i.e., six consecutive RBs). For example, the most significant bit (MSB) of the bitmap corresponds to the first RB group of the BWP. The RB group corresponding to the bit set to 1 is allocated as the frequency domain resource of the CORESET.

[0098] -duration: Indicates the time domain resource of the CORESET. It indicates the number of consecutive OFDMA symbols in the CORESET. For example, duration is set to one of 1 to 3.

[0099] -cce-REG-MappingType: indicates the CCE to REG mapping type. Both interleaved and non-interleaved types are supported.

[0100] -precoderGranularity: Indicates the precoder granularity in the frequency domain.

[0101] -tci-StatesPDCCH: Provides information indicating the Transmission Configuration Indication (TCI) state of the PDCCH (eg, TCI-StateID). The TCI state is used to provide a quasi-co-location relationship between the DL RS in the RS set (TCI-state) and the PDCCH DMRS port.

[0102] -tci-PresentInDCI: Indicates whether the TCI field is included in the DCI.

[0103] -pdcch-DMRS-ScramblingID: Provides information for initializing the PDCCH DMRS scrambling sequence.

[0104] To receive the PDCCH, the UE may monitor (e.g., blindly decode) a set of PDCCH candidates in a CORESET. A PDCCH candidate is a CCE that the UE monitors for PDCCH reception / detection. PDCCH monitoring may be performed in one or more CORESETs in an active DL BWP on each active cell configured with PDCCH monitoring. The set of PDCCH candidates monitored by the UE is defined as a PDCCH search space (SS) set. The SS set may be a common search space (CSS) set and a UE-specific search space (USS) set.

[0105] Table 4 lists exemplary PDCCH SSs.

[0106] [Table 4]

[0107]

[0108] The SS set may be configured by system information (e.g., MIB) or UE-specific high-layer signaling (e.g., RRC signaling). S or fewer SS sets may be configured in each DL BWP of a serving cell. For example, the following parameters / information may be provided for each SS set. Each SS set may be associated with a CORESET, and each CORESET configuration may be associated with one or more SS sets. -searchSpaceId: indicates the ID of the SS set. -controlResourceSetId: indicates the CORESET associated with the SS set.

[0109] - monitoringSlotPeriodicityAndOffset: indicates the PDCCH monitoring period (in time slots) and the PDCCH monitoring offset (in time slots).

[0110] -monitoringSymbolsWithinSlot: Indicates the first OFDMA symbol for PDCCH monitoring in a slot configured with PDCCH monitoring. The OFDMA symbols are indicated by a bitmap, and each bit of the bitmap corresponds to an OFDM symbol in the slot. The MSB of the bitmap corresponds to the first OFDM symbol of the slot. The OFDMA symbol corresponding to the bit set to 1 corresponds to the first symbol of the CORESET in the slot.

[0111] -nrofCandidates: indicates the number of PDCCH candidates for each AL={1,2,4,8,16} (eg, one of 0, 1, 2, 3, 4, 5, 6, and 8).

[0112] -searchSpaceType: Indicates whether the SS type is CSS or USS.

[0113] -DCI format: indicates the DCI format of the PDCCH candidate.

[0114] The UE may monitor PDCCH candidates in one or more SS sets in a time slot based on the CORESET / SS set configuration. The timing (e.g., time / frequency resource) at which the PDCCH candidates should be monitored is defined as the PDCCH (monitoring) timing. One or more PDCCH (monitoring) timings may be configured in a time slot.

[0115] Table 5 shows an exemplary DCI format transmitted on the PDCCH.

[0116] [Table 5]

[0117]

[0118] DCI format 0_0 can be used to schedule TB-based (or TB-level) PUSCH, and DCI format 0_1 ​​can be used to schedule TB-based (or TB-level) PUSCH or code block group (CBG)-based (or CBG-level) PUSCH. DCI format 1_0 can be used to schedule TB-based (or TB-level) PDSCH, and DCI format 1_1 can be used to schedule TB-based (or TB-level) PDSCH or CBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0 / 0_1 can be referred to as UL grant DCI or UL scheduling information, and DCI format 1_0 / 1_1 can be referred to as DL grant DCI or DL ​​scheduling information. DCI format 2_0 is used to transmit dynamic slot format information (e.g., dynamic slot format indicator (SFI)) to the UE, and DCI format 2_1 is used to transmit DL preemptive information to the UE. DCI format 2_0 and / or DCI format 2_1 can be transmitted to a corresponding group of UEs on a group common PDCCH (PDCCH pointing to a group of UEs). DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCI formats, while DCI format 0_1 ​​and DCI format 1_1 may be referred to as non-fallback DCI formats. Under the fallback DCI format, the DCI size / field configuration remains the same regardless of the UE configuration. In contrast, under the non-fallback DCI format, the DCI size / field configuration varies according to the UE configuration.

[0119] UL channel structure

[0120] The UE transmits a relevant signal to the BS on a UL channel to be described later, and the BS receives a relevant signal from the UE through the UL channel to be described later.

[0121] (1) Physical Uplink Control Channel (PUCCH)

[0122] The PUCCH carries UCI, HARQ-ACK and / or Scheduling Request (SR), and is divided into a short PUCCH and a long PUCCH according to a PUCCH transmission length.

[0123] The UCI includes the following information.

[0124] -SR: Information used to request UL-SCH resources.

[0125] -HARQ-ACK: A response to a DL data packet (e.g., a codeword) on the PDSCH. HARQ-ACK indicates whether the DL data packet is successfully received. In response to a single codeword, a 1-bit HARQ-ACK may be sent. In response to two codewords, a 2-bit HARQ-ACK may be sent. The HARQ-ACK response includes a positive ACK (abbreviated as ACK), a negative ACK (NACK), a discontinuous transmission (DTX), or NACK / DTX. The term "HARQ-ACK" may be used interchangeably with HARQ ACK / NACK and ACK / NACK.

[0126] -CSI: Feedback information for DL ​​channels. Multiple-input multiple-output (MIMO) related feedback information includes RI and PMI.

[0127] Table 6 shows an exemplary PUCCH format. Based on PUCCH transmission duration, the PUCCH format may be divided into short PUCCH (formats 0 and 2) and long PUCCH (formats 1, 3, and 4).

[0128] [Table 6]

[0129]

[0130] PUCCH format 0 transmits up to 2 bits of UCI and is mapped in a sequence-based manner for transmission. Specifically, the UE sends a specific UCI to the BS by sending one of multiple sequences on the PUCCH of PUCCH format 0. Only when the UE sends a positive SR, the UE sends the PUCCH of PUCCH format 0 in the PUCCH resource for the corresponding SR configuration. PUCCH format 1 transmits up to 2 bits of UCI and the modulation symbol of the UCI is extended in the time domain using an orthogonal cover code (OCC) (configured differently depending on whether frequency hopping is performed). DMRS is sent in symbols where modulation symbols are not sent (i.e., sent in time division multiplexing (TDM)). PUCCH format 2 transmits more than 2 bits of UCI and the modulation symbol of the DCI is sent with the DMRS in frequency division multiplexing (FDM). DMRS is located in symbols #1, #4, #7 and #10 of a given RB with a density of 1 / 3. Pseudo-noise (PN) sequences are used for DMRS sequences. For 2-symbol PUCCH format 2, frequency hopping can be enabled.

[0131] PUCCH format 3 does not support UE multiplexing in the same PRBS and transmits UCI of more than 2 bits. In other words, the PUCCH resources of PUCCH format 3 do not include OCC. The modulation symbols and DMRS are sent in TDM.

[0132] PUCCH format 4 supports multiplexing of up to 4 UEs in the same PRBS and transmits more than 2 bits of UCI. In other words, the PUCCH resources of PUCCH format 3 include OCC. The modulation symbols and DMRS are sent in TDM.

[0133] (2) Physical Uplink Shared Channel (PUSCH)

[0134] The PUSCH carries UL data (e.g., UL shared channel transport block (UL-SCH TB)) and / or UL control information (UCI), and transmits the PUSCH based on a cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) waveform or a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) waveform. When transmitting the PUSCH based on the DFT-s-OFDM waveform, the UE transmits the PUSCH by applying transform precoding. For example, when transform precoding is not allowed (e.g., transform precoding is disabled), the UE may transmit the PUSCH based on the CP-OFDM waveform. When transform precoding is allowed (e.g., transform precoding is enabled), the UE may transmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmission may be dynamically scheduled by a UL grant in the DCI or may be semi-statically scheduled based on higher layer (e.g., RRC) signaling (and / or layer 1 (L1) signaling (e.g., PDCCH)) (configured grant). PUSCH transmission may be performed in a codebook-based or non-codebook-based manner.

[0135] System information acquisition

[0136] Figure 5 The system information (SI) acquisition process is illustrated. The UE can acquire access stratum (AS) / non-access stratum (NAS) information in the SI acquisition process. The SI acquisition process can be applied to UEs in RRC_IDLE, RRC_INACTIVE and RRC_CONNECTED states.

[0137] SI is divided into a master information block (MIB) and multiple system information blocks (SIBs). MIB and multiple SIBs are further divided into minimum SI and other SI. Minimum SI may include MIB and systemInformationBlock1 (SIB1), thereby carrying basic information required for initial access and information required to obtain other SI. SIB1 may also be referred to as remaining minimum system information (RMSI). For details, please refer to the following.

[0138] -MIB includes information / parameters related to the reception of SIB1 and is sent on the PBCH of the SSB. The UE assumes that the half-frame including the SSB is repeated every 20ms during the initial cell selection. The UE can determine from the MIB whether there is any control resource set (CORESET) for the Type0-PDCCH common search space. The Type0-PDCCH common search space is a type of PDCCH search space and is used to send a PDCCH that schedules SI messages. In the presence of a Type0-PDCCH common search space, the UE can determine (i) multiple consecutive RBs and one or more consecutive symbols included in the CORESET and (ii) the PDCCH timing (e.g., the time domain position where the PDCCH will be received) based on the information included in the MIB (e.g., pdcch-ConfigSIB1). In the absence of a Type0-PDCCH common search space, pdcch-ConfigSIB1 provides information about the frequency location where the SSB / SIB1 exists and about the frequency range in the absence of any SSB / SIB1.

[0139] -SIB1 includes information related to the availability and scheduling (e.g., transmission period and SI window size) of the remaining SIBs (hereinafter referred to as SIBx, where x is an integer equal to or greater than 2). For example, SIB1 may indicate whether SIBx is broadcast periodically or on demand according to UE request. If SIBx is provided on demand, SIB1 may include information required for the UE to send an SI request. The PDCCH that schedules SIB1 is sent in the Type0-PDCCH common search space, and SIB1 is sent on the PDSCH indicated by the PDCCH.

[0140] - SIBx is included in the SI message and sent on the PDSCH. Each SI message is sent within a periodic time window (ie, SI window).

[0141] Beam Alignment

[0142] Figure 6 An exemplary multi-beam transmission of SSB is illustrated.

[0143] Beam scanning refers to changing the beam (direction) of a wireless signal over time at a transmit receive point (TRP) (eg, BS / cell) (hereinafter, the terms beam and beam direction are used interchangeably). Fig.10, SSBs can be sent periodically by beam scanning. In this case, the SSB index is implicitly linked to the SSB beam. The SSB beam can be changed on an SSB (index) basis or on an SS (index) group basis. In the latter case, the same SSB beam is maintained in the SSB (index) group. That is, for multiple consecutive SSBs, the transmission beam direction of the SSB is repeated. Depending on the frequency band of the carrier, the maximum number of SSB transmissions L allowed in the SSB burst set is 4, 8, or 64. The maximum number of SSB beams in the SSB burst set can be given according to the frequency band of the carrier as follows.

[0144] - For frequency range up to 3 GHz, maximum number of beams = 4

[0145] - For the frequency range of 3 GHz to 6 GHz, maximum number of beams = 8

[0146] - For the frequency range of 6 GHz to 52.6 GHz, maximum number of beams = 64

[0147] In the absence of multi-beam transmission, the number of SSB beams is 1.

[0148] When a UE attempts to initially access a BS, the UE may align the beam with the BS based on the SSB. For example, the UE performs SSB detection and then identifies the best SSB. Subsequently, the UE may send a RACH preamble in a PRACH resource linked to / corresponding to the index (i.e., beam) of the best SSB. Even after initial access, the SSB may be used for beam alignment between the BS and the UE.

[0149] Random Access Channel (RACH) Procedure

[0150] When the UE first accesses the BS or has no radio resources for signal transmission, the UE may perform a RACH procedure for the BS.

[0151] The RACH procedure can be used for various purposes. For example, the RACH procedure can be used for initial network access starting from RRC_IDLE, RRC connection reestablishment procedure, handover, UE-triggered UL data transmission, transition starting from RRC_INACTIVE, time alignment establishment in SCell addition, other system information (OSI) requests and beam failure recovery, etc. The UE can obtain UL synchronization and UL transmission resources from the RACH procedure.

[0152] The RACH procedure may be divided into a contention-based RACH procedure and a contention-free RACH procedure. The contention-based RACH procedure may be divided into a 4-step RACH procedure (4-step RACH) and a 2-step RACH procedure (2-step RACH).

[0153] (1) 4-step RACH: Type 1 random access procedure

[0154] Figure 7 is a diagram illustrating an exemplary 4-step RACH procedure.

[0155] If the (contention-based) RACH procedure is performed in four steps (i.e., a 4-step RACH procedure), the UE may send a message (message 1 (Msg1)) including a preamble associated with a specific sequence on a physical random access channel (PRACH) (701), and may receive a response message (random access response (RAR) message) to the preamble on a PDCCH and a PDSCH associated therewith (message 2 (Msg2)) (703). The UE may send a message (message 3 (Msg3)) including a PUSCH based on scheduling information in the RAR (705). The UE may perform a contention resolution procedure by receiving a PDCCH signal and a PDSCH signal associated therewith. For this purpose, the UE may receive a message (message 4 (Msg4)) (707) containing contention resolution information regarding the contention resolution procedure from the BS.

[0156] The 4-step RACH procedure of the UE can be summarized as shown in Table 7 below.

[0157] [Table 7]

[0158]

[0159] First, the UE may send a random access preamble on the PRACH in the UL as Msg1 of the RACH procedure.

[0160] Two different lengths of random access preamble sequences are supported: the long sequence length 839 is suitable for SCSs of 1.25kHz and 5kHz, and the short sequence length 139 is suitable for SCSs of 15kHz, 30kHz, 60kHz, and 120kHz.

[0161] Multiple preamble formats are defined by one or more RACH OFDM symbols and different cyclic prefixes (and / or guard times). The RACH configuration of the initial bandwidth of the primary cell (Pcell) may be included in the system information of the cell and provided to the UE. The RACH configuration includes information about the SCS of the PRACH, available preambles, preamble formats, etc. The RACH configuration includes information about the association between the SSB and the RACH (time-frequency) resources. The UE sends a random access preamble on the RACH time-frequency resource associated with the detected or selected SSB.

[0162] The threshold of the SSB may be configured by the network to be associated with the RACH resource. The RACH preamble may be sent or resent based on an SSB having a reference signal received power (RSRP) measured thereon that satisfies the threshold. For example, the UE may select one of the SSBs that satisfies the threshold and send or resend the RACH preamble based on the RACH resource associated with the selected SSB. For example, after resending the RACH preamble, the UE may reselect one of the SSBs and resend the RACH preamble based on the RACH resource associated with the reselected SSB. That is, the RACH resource used to resend the RACH preamble may be the same and / or different from the RACH resource used to send the RACH preamble.

[0163] When the BS receives a random access preamble from the UE, the BS sends a RAR message (Msg2) to the UE. The PDCCH that schedules the PDSCH carrying the RAR is cyclically redundancy checked (CRC) scrambled by the random access (RA) radio network temporary identifier (RNTI) (RA-RNTI) and then transmitted. After detecting the PDCCH scrambled by the RA-RNTI for CRC, the UE can receive the RAR from the PDSCH scheduled by the DCI carried on the PDCCH. The UE checks whether the RAR includes RAR information in response to the preamble (ie, Msg1) sent by the UE. The presence or absence of RAR information in response to Msg1 sent by the UE can be determined based on whether there is a random access preamble ID of the preamble sent by the UE. If there is no response to Msg1, the UE can resend the RACH preamble within a predetermined number of times while performing power boosting. The UE can calculate the PRACH transmit power for resending the preamble based on the most recent transmit power, power increment, and power boost counter.

[0164] The RAR information may include a preamble sequence sent by the UE, a temporary cell RNTI (TC-RNTI) assigned by the BS to the UE attempting random access, and UL transmission time alignment information, UL transmission power adjustment information, and UL radio resource allocation information. If the UE receives its own RAR information on the PDSCH, the UE can obtain time advance information, initial UL grant, and TC-RNTI for UL synchronization. The timing advance information can be used to control the UL signal transmission timing. In order to better align the UE's PUSCH / PUCCH transmission with the subframe timing at the network, the network (e.g., BS) can obtain the timing advance information based on the timing information detected from the PRACH preamble received from the UE, and send the timing advance information to the UE. The UE can send a UL signal as Msg3 of the RACH process on the UL shared channel based on the RAR information. Msg3 may include an RRC connection request and a UE identifier. In response to Msg3, the network may send Msg4, which may be regarded as a contention resolution message on the DL. After receiving Msg4, the UE may enter the RRC_CONNECTED state.

[0165] As described above, the UL grant in the RAR may schedule the PUSCH transmission to the BS. The PUSCH carrying the initial UL transmission based on the UL grant in the RAR is also referred to as Msg3 PUSCH. The content of the RAR UL grant may start from the MSB and end at the LSB, and the content may be as given in Table 8.

[0166] [Table 8]

[0167]

[0168] The transmit power of Msg3 PUSCH is determined using the TPC command. For example, the TPC command may be interpreted as shown in Table 9.

[0169] [Table 9]

[0170] TPC Command Value [dB] 0 -6 1 -4 2 -2 3 0 4 2 5 4 6 6 7 8

[0171] (2) 2-step RACH: Type 2 random access procedure

[0172] Figure 8 is a diagram illustrating an exemplary 2-step RACH procedure.

[0173] A 2-step RACH procedure that performs a (contention-based) RACH procedure in two steps has been proposed to simplify the RACH procedure, ie, to achieve low signaling overhead and low latency.

[0174] The operation of sending Msg1 and Msg3 in the 4-step RACH process can be performed as an operation in which the UE sends a message (message A (MsgA)) including PRACH and PUSCH in the 2-step RACH process. The operation of the BS sending Msg2 and Msg4 in the 4-step RACH process can be performed as an operation in which the BS sends a message (message B (MsgB)) including RAR and contention resolution information in the 2-step RACH process.

[0175] That is, in the 2-step RACH procedure, the UE may combine Msg1 and Msg3 of the 4-step RACH procedure into one message (eg, MsgA) and send the one message to the BS (801).

[0176] In addition, in the 2-step RACH procedure, the BS may combine Msg2 and Msg4 of the 4-step RACH procedure into one message (eg, MsgB), and send the one message to the UE (S803).

[0177] Based on the combination of these messages, a 2-step RACH procedure can provide a low latency RACH procedure.

[0178] Specifically, MsgA of the 2-step RACH process may include the PRACH preamble included in Msg1 and the data included in Msg3. MsgB of the 2-step RACH process may include the RAR included in Msg2 and the contention resolution information included in Msg4.

[0179] (3) Non-contention RACH

[0180] Fig. 9 is a diagram illustrating an exemplary contention-free RACH procedure.

[0181] The contention-free RACH process can be performed when the UE switches to another cell or BS or when requested by a command from the BS. The basic steps of the contention-free RACH process are similar to those of the contention-based RACH process. However, in the contention-free RACH process, the BS allocates the preamble to be used by the UE (hereinafter, the dedicated random access preamble) to the UE (901), which is different from the contention-based RACH process in which the UE arbitrarily selects the preamble to be used from a plurality of random access preambles. Information about the dedicated random access preamble can be included in an RRC message (e.g., a handover command) or provided to the UE via a PDCCH command. When the RACH process is started, the UE sends the dedicated random access preamble to the BS (903). When the UE receives the RAR from the BS, the RACH process is completed (905).

[0182] In the contention-free RACH procedure, the CSI request field in the RAR UL grant indicates whether the UE includes aperiodic CSI reporting in the corresponding PUSCH transmission. The SCS for Msg3 PUSCH transmission is provided by RRC parameters. The UE can transmit PRACH and Msg3 PUSCH on the same UL carrier of the same serving cell. The UL BWP for Msg3 PUSCH transmission is indicated by System Information Block 1 (SIB1).

[0183] (4) Mapping between SSB and PRACH resources (timing)

[0184] Fig.10 and Fig.11 is a diagram illustrating transmission of an SSB and a PRACH resource linked to the SSB according to various embodiments of the present disclosure.

[0185] In order to communicate with one UE, the BS may need to find out what the best beam direction between the BS and the UE is. Since it is expected that the best beam direction will change according to the movement of the UE, the BS needs to continuously track the best beam direction. The process of finding out the best beam direction between the BS and the UE is called a beam acquisition process, and the process of continuously tracking the best beam direction between the BS and the UE is called a beam tracking process. The beam acquisition process may be required in the following situations: 1) initial access when the UE first attempts to access the BS; 2) handover when the UE switches from one BS to another BS; and 3) beam recovery for recovering beam failure. Beam failure means that when performing beam tracking to find out the best beam between the UE and the BS, the UE loses the best beam and is therefore unable to maintain the best communication state with the BS or is unable to communicate with the BS.

[0186] In the NR system, a multi-stage beam acquisition process for acquiring a beam in an environment using multiple beams is being discussed. In the multi-stage beam acquisition process, the BS and the UE perform connection establishment by using a wide beam in the initial access phase. After the connection establishment is completed, the BS and the UE perform the highest quality communication by using a narrow beam. The beam acquisition process in the NR system applicable to various embodiments of the present disclosure can be performed as follows.

[0187] -1) The BS sends a synchronization block for each wide beam to allow the UE to discover the BS in the initial access phase, i.e., so that the UE finds the best wide beam to be used in the first stage of beam acquisition by performing cell search or cell acquisition and measuring the channel quality of each wide beam.

[0188] -2) The UE performs a cell search on the synchronization block of each beam and acquires a DL beam based on the detection result of each beam.

[0189] -3) The UE performs a RACH procedure to inform the BS that the UE discovers that the UE intends to access the BS.

[0190] -4) The BS connects or associates the synchronization block transmitted for each beam with the PRACH resource to be used for PRACH transmission to allow the UE to simultaneously inform the RACH process and DL beam acquisition results (e.g., beam index) at the wide beam level. If the UE performs a RACH process on the PRACH resource associated with the best beam direction found by the UE, the BS obtains information about the DL beam suitable for the UE by receiving the PRACH preamble.

[0191] In a multi-beam environment, whether the UE and / or TRP can accurately determine the direction of the transmit (TX) and / or receive (RX) beam between the UE and the TRP is a question. In a multi-beam environment, reception for signal transmission or beam scanning for signal reception may be considered based on the TX / RX reciprocal capability of the TRP (e.g., BS) or the UE. The TX / RX reciprocal capability of the TRP and the UE is also referred to as the TX / RX beam correspondence of the TRP and the UE. In a multi-beam environment, if the TX / RX reciprocal capability of the TRP and the UE is invalid (i.e., not maintained), the UE may not be able to send UL signals in the beam direction in which the UE receives DL signals. This is because the UL optimal path may be different from the DL optimal path. If the TRP is able to determine the TRP RX beam for UL reception based on the DL measurement results of the UE's measurement of one or more TX beams of the TRP and / or if the TRP is able to determine the TRP TX beam for DL ​​transmission based on the UL measurement results of the TRP's measurement of one or more RX beams of the TRP, the TX / RX beam correspondence of the TRP can be valid (maintained). If the UE is able to determine the UE RX beam for UL transmission based on the DL measurement results of the UE's measurement of one or more RX beams of the UE and / or if the UE is able to determine the UE TX beam for DL ​​reception based on an indication from the TRP related to the UL measurement results of one or more TX beams of the UE, the TX / RX beam correspondence of the UE can be valid (maintained).

[0192] On the DL, the BS can dynamically allocate resources for DL ​​transmission to the UE through PDCCH (including DCI format 1_0 or DCI format 1_1). In addition, the BS can indicate to a specific UE through PDCCH (including DCI format 2_1) that some resources pre-scheduled for the UE have been preempted for signal transmission to another UE. In addition, the BS can configure the DL assignment period through high-layer signaling in a semi-persistent scheduling (SPS) scheme and configure the signal activation / deactivation of the configured DL assignment through PDCCH to provide the UE with the DL assignment for initial HARQ transmission. When retransmission of the initial HARQ transmission is required, the BS explicitly schedules the retransmission resources through PDCCH. When a DCI-based DL assignment conflicts with an SPS-based DL assignment, the UE may give priority to the DCI-based DL assignment.

[0193] Similar to DL, for UL, the BS can dynamically allocate resources for UL transmission to the UE through PDCCH (including DCI format 0_0 or DCI format 0_1). In addition, the BS can allocate UL resources for initial HARQ transmission to the UE based on the configured grant (CG) method (similar to SPS). Although dynamic scheduling involves PDCCH for PUSCH transmission, the configured grant does not involve PDCCH for PUSCH transmission. However, UL resources for retransmission are explicitly allocated through PDCCH. In this way, the operation of the BS pre-configuring UL resources without dynamic grant (DG) (for example, by scheduling UL grant of DCI) is called "CG". Two types of CG are defined.

[0194] - Type 1: UL grant with a predetermined period is provided through higher layer signaling (without L1 signaling).

[0195] -Type 2: The period of UL grant is configured through higher layer signaling, and the activation / deactivation of CG is signaled through PDCCH to provide UL grant.

[0196] Fig.12 The exemplary UL transmission operation of the UE is illustrated. The UE can be based on DG( Fig.12 (a)) or based on CG( Fig.12 (b)) to send the expected packet.

[0197] Resources for CG can be shared among multiple UEs. UL signal transmission based on CG from each UE can be identified by time / frequency resources and RS parameters (e.g., different cyclic shifts, etc.). Therefore, when a UE cannot send a UL signal due to a signal conflict, the BS can identify the UE and explicitly send a retransmission authorization for the corresponding TB to the UE.

[0198] CG supports K repetitions including initial transmission for the same TB. Based on the resources used for the initial transmission, the same HARQ process ID is determined for the K-repetition UL signals. The redundancy version (RV) of the K-repetition TB has one of the modes {0,2,3,1}, {0,3,0,3}, and {0,0,0,0}.

[0199] Fig.13 An exemplary CG-based repeated transmission is illustrated.

[0200] The UE continues to perform repeated transmission until one of the following conditions is met:

[0201] - Successfully received UL grant for the same TB;

[0202] -TB is repeated K times; and

[0203] - (In option 2) the end time of period P is reached.

[0204] Similar to License Assisted Access (LAA) in the conventional 3GPP LTE system, the use of unlicensed bands for cellular communications is also being considered in the 3GPP NR system.

[0205] Unlike LAA, standalone (SA) operation is for NR cells in unlicensed bands (hereinafter referred to as NR unlicensed cells (UCells)). For example, PUCCH, PUSCH, and PRACH transmissions can be supported in NR UCells.

[0206] On LAA UL, with the introduction of asynchronous HARQ process, there is no additional channel such as Physical HARQ Indicator Channel (PHICH) for indicating HARQ-ACK information for PUSCH to the UE. Therefore, accurate HARQ-ACK information cannot be used to adjust the contention window (CW) size in the UL LBT process. In the UL LBT process, when a UL grant is received in the nth subframe, the first subframe of the most recent UL transmission burst before the (n-3)th subframe has been configured as a reference subframe, and the CW size is adjusted based on the New Data Indicator (NDI) of the HARQ process ID corresponding to the reference subframe. That is, when the BS switches the NDI or indicates retransmission of one or more transport blocks (TBs) based on one or more TBs, the following method is introduced: when it is assumed that the PUSCH cannot be sent in the reference subframe due to a conflict with other signals, the CW size is increased to the next maximum CW size of the currently applied CW size in a set of pre-agreed CW sizes, or when it is assumed that the PUSCH has been successfully sent in the reference subframe without any conflict with other signals, the CW size is initialized to the minimum value (e.g., CWmin).

[0207] In an NR system to which various embodiments of the present disclosure are applicable, up to 400 MHz per component carrier (CC) may be allocated / supported. When a UE operating in such a wideband CC always operates with a radio frequency (RF) module turned on in all CCs, the battery power consumption of the UE may increase.

[0208] Alternatively, considering various use cases (e.g., eMBB, URLLC, mMTC, etc.) operating within a single wideband CC, different parameter sets (e.g., SCS) may be supported for each frequency band within the CC.

[0209] Alternatively, each UE may have a different maximum bandwidth capability.

[0210] In this regard, the BS may indicate to the UE to operate only in a partial bandwidth, rather than operating in the total bandwidth of the wideband CC. The partial bandwidth may be defined as a wideband part (BWP).

[0211] A BWP may be a subset of continuous RBs on the frequency axis. One BWP may correspond to one parameter set (eg, SCS, CP length, slot / mini-slot duration, etc.).

[0212] The BS may configure multiple BWPs in one CC configured for the UE. For example, the BS may configure a BWP that occupies a relatively small frequency region in the PDCCH monitoring slot and schedule the PDSCH indicated (or scheduled) by the PDCCH with a larger BWP. Alternatively, when the UEs are concentrated on a specific BWP, the BS may configure another BWP for some of the UEs for load balancing. Alternatively, the BS may exclude a certain spectrum of the entire bandwidth and configure BWPs on both sides of the cell in the same slot in consideration of frequency domain inter-cell interference elimination between adjacent cells.

[0213] The BS may configure at least one DL / UL BWP for a UE associated with a wideband CC, activate at least one of the DL / UL BWPs configured at a specific time point (through L1 signaling (e.g., DCI, etc.), MAC signaling, or RRC signaling), and instruct switching to another configured DL / UL BWP (through L1 signaling, MAC signaling, or RRC signaling). In addition, when a timer value (e.g., a BWP inactivity timer value) expires, the UE may switch to a predetermined DL / UL BWP. The activated DL / UL BWP may be referred to as an active DL / UL BWP. During initial access or before an RRC connection is established, the UE may not receive a configuration for a DL / UL BWP from the BS. The DL / UL BWP assumed by the UE in this situation is defined as the initial active DL / UL BWP.

[0214] Fig.14An exemplary wireless communication system supporting an unlicensed frequency band applicable to the present disclosure is illustrated.

[0215] In the following description, a cell operating in a licensed band (L band) is defined as an L cell, and a carrier of the L cell is defined as (DL / UL) LCC. A cell operating in an unlicensed band (U band) is defined as a U cell, and a carrier of the U cell is defined as (DL / UL) UCC. A carrier / carrier frequency of a cell may refer to an operating frequency (e.g., center frequency) of the cell. Cells / carriers (e.g., CCs) are collectively referred to as cells.

[0216] When Figure 7 As illustrated in (a) of FIG. 1 , when the BS and the UE send and receive signals on the LCC and UCC of carrier aggregation, the LCC and the UCC may be configured as a primary CC (PCC) and a secondary CC (SCC), respectively. Figure 7 As illustrated in (b), the BS and the UE can send and receive signals on one UCC or on a carrier-aggregated UCC. In other words, the BS and the UE can send and receive signals only on the UCC without using any LCC. For SA operation, PRACH, PUCCH, PUSCH, and SRS transmission can be supported on the UCell.

[0217] Signal transmission and reception operations in a license-exempt band as described in the present disclosure may be applied to the above-mentioned deployment scenarios (unless otherwise specified).

[0218] Unless otherwise stated, the following definitions apply to the following terms used in this disclosure.

[0219] - Channel: A carrier or a portion of a carrier consisting of a set of contiguous RBs on which a channel access procedure (CAP) is performed in a shared spectrum,

[0220] - Channel Access Procedure (CAP): A procedure to evaluate channel availability based on sensing before signal transmission in order to determine whether other communication nodes are using the channel. The basic sensing unit is a duration of T sl = 9us sensing time slot. The BS or UE senses the time slot during the sensing time slot duration. When the power detected within at least 4us within the sensing time slot duration is less than the energy detection threshold X Thresh The sensing time slot duration is T sl is considered idle. Otherwise, the sensing time slot duration T sl is considered busy. CAP can also be called Listen Before Talk (LBT).

[0221] - Channel occupancy: Transmissions on the channel from BS / UE after CAP.

[0222] - Channel Occupancy Time (COT): The total time that the BS / UE and any BS / UEs sharing the channel occupancy perform transmissions on the channel after the CAP. Regarding COT determination, if the transmission gap is less than or equal to 25us, the gap duration may be accounted for in the COT.

[0223] In addition, the COT may be shared for transmission between the BS and the corresponding UE.

[0224] Specifically, sharing the UE-initiated COT with the BS may mean the following operation: the UE assigns a portion of the occupied channel to the BS through LBT based on random backoff (e.g., Category 3 (Cat-3) LBT or Category 4 (Cat-4) LBT), and when the channel is successfully confirmed to be idle through LBT after performing LBT without random backoff in a timing gap occurring before the UL transmission end timing of the UE starts using DL transmission (e.g., Category 1 (Cat-1) LBT or Category 2 (Cat-2) LBT), the BS performs DL transmission using the remaining COT of the UE.

[0225] In addition, sharing the gNB-initiated COT with the UE may mean the following operation: the BS assigns a portion of the occupied channel to the UE through LBT based on random backoff (e.g., Cat-3 LBT or Cat-4 LBT), and when the channel is successfully confirmed to be idle through LBT after performing LBT without random backoff in a timing gap occurring before the DL transmission end timing of the BS is started using UL transmission (e.g., Cat-1 LBT or Cat-2 LBT), the UE performs UL transmission using the remaining COT of the BS.

[0226] -DL transmit burst: A collection of transmissions from a BS without any gap greater than 16us. Transmissions from a BS separated by gaps greater than 16us are considered separate DL transmit bursts. The BS may perform transmissions after a gap without sensing channel availability within a DL transmit burst.

[0227] -UL transmit burst: A collection of transmissions from a UE without any gap greater than 16us. Transmissions from a UE separated by gaps greater than 16us are considered separate UL transmit bursts. The UE may perform transmissions after a gap without sensing channel availability within a DL transmit burst.

[0228] -Discovery burst: A DL transmission burst including a set of signals and / or channels confined within a window and associated with a duty cycle. The discovery burst may include transmissions initiated by the BS including PSS, SSS, and cell-specific RS (CRS) and also including non-zero power CSI-RS. In an NR system, the discovery burst may include transmissions initiated by the BS including at least SS / PBCH blocks and also including PDCCH for scheduling PDSCH carrying SIB1, PDSCH carrying SIB1, and / or CORESET transmissions of non-zero power CSI-RS.

[0229] Fig.15 An exemplary method of occupying resources in a license-exempt band is illustrated.

[0230] Reference Fig.15 , a communication node (e.g., BS or UE) operating in an unlicensed band should determine whether other communication nodes are using the channel before sending a signal. For this purpose, the communication node can perform CAP to access the channel to be sent in the unlicensed band. CAP can be performed based on sensing. For example, a communication node can determine whether other communication nodes are sending signals on the channel by carrier sensing (CS) before sending a signal. Determining that other communication nodes are not sending signals is defined as a confirmation of clear channel assessment (CCA). In the presence of a CCA threshold (e.g., Xthresh) predefined or configured by high-level (e.g., RRC) signaling, when energy above the CCA threshold is detected in the channel, the communication node can determine that the channel is busy. Otherwise, the communication node can determine that the channel is idle. When it is determined that the channel is idle, the communication node can start sending signals in the unlicensed band. CAP can be replaced by LBT.

[0231] Table 10 describes an exemplary CAP supported in NR-U.

[0232] [Table 10]

[0233]

[0234] In a wireless communication system supporting an unlicensed band, a cell (or carrier (e.g., CC)) or BWP configured for a UE may be a broadband with a larger bandwidth (BW) than conventional LTE. However, the BW of a CCA that requires independent LBT operation may be limited according to regulations. A subband (SB) for independently performing LBT is defined as an LBT-SB. Then, multiple LBT-SBs may be included in one broadband cell / BWP. The RB set included in the LBT-SB may be configured by a high-layer (e.g., RRC) signaling. Accordingly, one or more LBT-SBs may be included in one cell / BWP based on (i) the BW of the cell / BWP and (ii) the RB set allocation information. Multiple LBT-SBs may be included in the BWP of a cell (or carrier). The LBT-SB may be, for example, a 20-MHz band. The LBT-SB may include multiple consecutive (P) RBs in the frequency domain, and may therefore be referred to as a (P) RB set. In Europe, two LBT operations are defined: frame-based equipment (FBE) and load-based equipment (LBE). In FBE, a fixed frame consists of a channel occupancy time (e.g., 1 to 10ms) (a time period during which a communication node can continue to transmit once it has successfully accessed the channel) and an idle period corresponding to at least 5% of the channel occupancy time, and CCA is defined as an operation of observing the channel during a CCA time slot (at least 20us) at the end of the idle period. The communication node periodically performs CCA based on the fixed frame. When the channel is not occupied, the communication node transmits during the channel occupancy time, and when the channel is occupied, the communication node postpones transmission and waits until the CCA time slot in the next cycle.

[0235] In LBE, the communication node can set q∈{4,5,…,32} and then perform CCA for one CCA slot. When the channel is not occupied in the first CCA slot, the communication node can ensure a time period of at most (13 / 32)q ms and send data in the time period. When the channel is occupied in the first CCA slot, the communication node randomly selects N∈{1,2,…,q}, stores the selected value as the initial value, and then senses the channel state based on the CCA slot. Each time the channel is not occupied in the CCA slot, the communication node subtracts 1 from the stored counter value. When the counter value reaches 0, the communication node can ensure a time period of at most (13 / 32)q ms and send data.

[0236] The eNB / gNB or UE of the LTE / NR system should also perform LBT to transmit signals in an unlicensed band (referred to as the U band for convenience). When the eNB or UE of the LTE / NR system transmits a signal, other communication nodes such as Wi-Fi nodes should also perform LBT to avoid causing interference with the transmission of the eNB or UE. For example, in the Wi-Fi standard (801.11ac), the CCA threshold is defined as -62dBm for non-Wi-Fi signals and -82dBm for Wi-Fi signals. For example, when a non-Wi-Fi signal is received by a station (STA) or access point (AP) at a power greater than -62dBm, the STA or AP does not send other signals so as not to cause interference.

[0237] The UE performs type 1 or type 2 CAP for UL signal transmission in the U band. Generally, the UE can perform the CAP (e.g., type 1 or type 2) configured by the BS for UL signal transmission. For example, the CAP type indication information can be included in the UL grant (e.g., DCI format 0_0 or DCI format 0_1) for scheduling PUSCH transmission.

[0238] In the Type 1 UL CAP, the length of the time period spanned by the sensing slots sensed as idle before transmission is random. The Type 1 UL CAP may be applied to the following transmissions.

[0239] -PUSCH / SRS transmission scheduled and / or configured by the BS

[0240] - PUCCH transmission scheduled and / or configured by the BS

[0241] - Transmissions related to the Random Access Procedure (RAP)

[0242] Fig.16 A Type 1 CAP among CAPs of a UE for UL signal transmission and / or DL ​​signal transmission in a U band applicable to the present disclosure is illustrated.

[0243] First, refer to Fig.16 Describes UL signaling in the U-band.

[0244] The UE may delay for a duration T d The UE senses whether the channel is idle during the sensing time slot duration in the UE. After the counter N is decremented to 0, the UE may perform transmission (S934). According to the following process, the counter N is adjusted by sensing the channel during another time slot duration.

[0245] Step 1) Let N = N init , where N init is evenly distributed between 0 and CW pA random number between , go to step 4 (S1620).

[0246] Step 2) If N>0 and the UE chooses to decrement the counter, let N=N-1 (S1640).

[0247] Step 3) Sense the channel during the additional time slot duration, and if the additional time slot duration is idle (Yes), go to step 4. Otherwise (No), go to step 5 (S1650).

[0248] Step 4) If N=0 (Yes) (S1630), stop CAP (S1632). Otherwise (No), go to step 2.

[0249] Step 5) Sense the channel until a busy sensing time slot is detected or an additional delay duration T is sensed. d until all time slots are idle (S1660).

[0250] Step 6) If the additional delay duration T d If the channel is sensed to be idle during the duration of all time slots (yes), go to step 4. Otherwise (no), go to step 5 (S1670).

[0251] Table 11 shows an example of m applied to CAP p , minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW size vary according to the channel access priority category.

[0252] [Table 11]

[0253]

[0254] Delay duration T d According to the duration T f (16us)+m p The duration of each time slot is 9us, and T f The 16-us duration starts and includes the sensing time slot duration T sl .CW Wmin,p <=CW p <=CW max,p .CW p Set to CW min,p , and may be updated (CW size update) based on an explicit / implicit reception response to a previous UL burst (e.g., PUSCH) before step 1. p Can be initialized to CW based on explicit / implicit reception response to previous UL burst min，p, may be increased to the next higher allowed value, or may be maintained at the existing value. In a Type 2 UL CAP, the length of the time period spanned by the sensing slots sensed as idle before transmission is deterministic. Type 2 UL CAPs are classified into Type 2A UL CAP, Type 2B UL CAP, and Type 2C UL CAP. In a Type 2A UL CAP, the UE may select a sensing slot for at least the sensing duration T. short_dl The signal is sent immediately after the channel is sensed as idle during (=25us). short_dl Including duration T f (=16us) and the duration immediately following the sensing slot duration. In Type 2A UL CAP, T f The sensing time slot is included at the beginning of the duration. In a Type 2B UL CAP, the UE may f The signal is sent immediately after the channel is sensed as idle during (=16us). In Type 2B UL CAP, T f Includes a sensing slot in the last 9us of duration. In Type 2C UL CAP, the UE does not sense the channel before transmitting.

[0255] In order to allow the UE to send UL data in the U-band, the BS should successfully perform an LBT operation to send an UL grant in the U-band, and the UE should also successfully perform an LBT operation to send UL data. That is, the UE can attempt UL data transmission only when both the BS and the UE successfully perform their LBT operations. In addition, because a delay of at least 4 milliseconds is involved between the UL grant and the scheduled UL data in the LTE system, the earlier access of another transmitting node coexisting in the U-band during this time period can postpone the scheduled UL data transmission of the UE. In this context, a method of improving the efficiency of UL data transmission in the U-band is being discussed.

[0256] In order to support UL transmission with relatively high reliability and relatively low time delay, NR also supports CG type 1 and CG type 2 in which the BS pre-configures time, frequency and code resources for the UE through high-layer signaling (e.g., RRC signaling) or both high-layer signaling and L1 signaling (e.g., DCI). In the absence of a UL grant received from the BS, the UE can perform UL transmission in resources configured with type 1 or type 2. In type 1, the period of the CG, the offset from SFN=0, the time / frequency resource allocation, the number of repetitions, the DMRS parameters, the MCS / TB size (TBS), the power control parameters, etc. are all configured only by high-layer signaling such as RRC signaling (without L1 signaling). Type 2 is a scheme in which the period and power control parameters of the CG are configured through high-layer signaling such as RRC signaling and information about the remaining resources (e.g., the offset of the initial transmission timing, the time / frequency resource allocation, the DMRS parameters and the MCS / TBS) are indicated through active DCI as L1 signaling.

[0257] The AUL of LTE LAA and the CG of NR show large differences in the method of sending HARQ-ACK feedback for the PUSCH that the UE has sent without receiving UL grant, and in the presence or absence of UCI sent together with PUSCH. Although the HARQ process is determined by the equation of the symbol index, symbol period and number of HARQ processes in the CG of NR, explicit HARQ-ACK feedback information is sent in the AUL downlink feedback information (AUL-DFI) in LTE LAA. In addition, in LTE LAA, whenever AUL PUSCH transmission is performed, UCI including information such as HARQ ID, NDI and RV is also sent in the AUL UCI. In the case of NR's CG, the BS identifies the UE by the time / frequency resources and DMRS resources used by the UE for PUSCH transmission, while in the case of LTE LAA, the BS identifies the UE by the UEID explicitly included in the AUL UCI sent together with the PUSCH and the DMRS resources.

[0258] In a wireless communication system supporting the U-band, a cell (or carrier (e.g., CC)) or BWP configured for a UE may be broadband with a larger bandwidth (BW) than in conventional LTE. However, according to the specification, the BW of a CCA that requires independent LBT operation may be limited. If a subband (SB) for independently performing LBT is defined as an LBT-SB, multiple LBT-SBs may be included in one broadband cell / BWP. The RB set included in the LBT-SB may be configured by high-layer (e.g., RRC) signaling. Accordingly, one or more LBT-SBs may be included in one cell / BWP based on (i) the BW of the cell / BWP and (ii) RB set allocation information.

[0259] Fig.17 It is illustrated that a plurality of LBT-SBs are included in the U band.

[0260] Reference Fig.17 , multiple LBT-SBs may be included in the BWP of a cell (or carrier). The LBT-SB may be, for example, a 20MHz band. The LBT-SB may include multiple consecutive (P)RBs in the frequency domain and may therefore be referred to as a (P)RB set. Although not illustrated, a guard band (GB) may be included between the LBT-SBs. Therefore, the BWP may be configured in the form of {LBT-SB#0 (RB set #0) + GB#0 + LBT-SB#1 (RB set #1 + GB#1) + ... LBT-SB#(K-1) (RB set (#K-1))}. For convenience, the LBT-SB / RB index may be configured / defined to increase as the frequency band becomes higher starting from the low frequency band.

[0261] In the NR system, a massive multiple-input multiple-output (MIMO) environment in which the number of transmit / receive (Tx / Rx) antennas is significantly increased can be considered. That is, when considering a massive MIMO environment, the number of Tx / Rx antennas can be increased to tens or hundreds. The NR system supports communications in frequency bands above 6 GHz (i.e., millimeter bands). However, the millimeter band is characterized by a frequency characteristic in which the signal decays very quickly according to the distance due to the high frequency band used. Therefore, in NR systems equal to or higher than 6 GHz, beamforming (BF) is considered, in which the signal is sent in a specific direction (rather than omnidirectionally) with concentrated energy to compensate for the rapid propagation attenuation. Accordingly, for the purpose of improving performance, flexible resource allocation, and ease of beam control in frequency in a massive MIMO environment, a hybrid BF with analog BF and digital BF is required according to a combination of the positions of the applied BF weight vector / precoding vector.

[0262] Fig.18 is a block diagram illustrating an exemplary transmitter and receiver for hybrid BF.

[0263] In order to form a narrow beam in the millimeter frequency band, the following BF method is mainly considered: the BS or UE sends the same signal through multiple antennas by applying an appropriate phase difference to the antenna, thereby increasing the energy in a specific direction only. This BF method includes a digital BF for generating a phase difference for a digital baseband signal, an analog BF for generating a phase difference by using a time delay (i.e., a cyclic shift) for a modulated analog signal, and a hybrid BF with a digital BF and analog beamforming combined. The use of a radio frequency (RF) unit (or transceiver unit (TXRU)) for antenna elements to control the transmit power and phase control based on the antenna element enables independent BF for each frequency resource. However, it is not feasible to install TXRU in all of the approximately 100 antenna elements in terms of cost. That is, a large number of antennas are required to compensate for the rapid propagation attenuation in the millimeter frequency, and the digital BF requires as many RF components as the number of antennas (e.g., digital-to-analog converters (DACs), mixers, power amplifiers, and linear amplifiers). Therefore, the implementation of digital BF in the millimeter frequency band increases the price of the communication device. Therefore, when a large number of antennas are required as in the case of millimeter frequency bands, consider analog BF or hybrid BF. In analog BF, multiple antenna elements are mapped to a single TXRU and the beam direction is controlled by analog phase shifters. Because only one beam direction is generated within the total frequency band in analog BF, frequency-selective BF may not be achieved with analog BF. Hybrid BF is an intermediate form of digital BF and analog BF using B RF units that are fewer than Q antenna elements. In hybrid BF, the number of beam directions that can be used for simultaneous transmission is limited to B or less, depending on how the B RF units are connected to the Q antenna elements.

[0264] Beam Management (BM)

[0265] BM refers to a series of processes for acquiring and maintaining a set of BS beams (transmission and reception point (TRP) beams) and / or a set of UE beams that can be used for DL ​​and UL transmission / reception. BM may include the following processes and terms.

[0266] - Beamforming: An operation where a BS or UE measures the characteristics of a received beamforming signal

[0267] -Beam determination: The operation by which the BS or UE selects its Tx / Rx beam

[0268] -Beam scanning: An operation that covers a spatial area by using Tx and / or Rx beams within a specified time slot according to a predetermined method

[0269] -Beam reporting: The UE reports information about the beamformed signal based on beam measurement operations.

[0270] The BM procedure may be divided into (1) a DL BM procedure using SSB or CSI-RS and (2) a UL BM procedure using SRS. In addition, each BM procedure may include Tx beam scanning for determining a Tx beam and Rx beam scanning for determining an Rx beam.

[0271] The DL BM process may include (1) sending a beamformed DL RS (eg, CSI-RS or SSB) from the BS and (2) beam reporting from the UE.

[0272] The beam report may include a preferred DL RS ID and a reference signal received power (RSRP) corresponding to the preferred DL RS ID. The DL RS ID may be a SSB resource indicator (SSBRI) or a CSI-RS resource indicator (CRI).

[0273] Fig.19 is a diagram illustrating an exemplary BF using SSB and CSI-RS.

[0274] Reference Fig.19 , SSB beam and CSI-RS beam can be used for beam measurement. The measurement indicator is RSRP for each resource / block. SSB can be used for coarse beam measurement, while CSI-RS can be used for fine beam measurement. SSB can be used for both Tx beam scanning and Rx beam scanning. SSB-based Rx beam scanning can be performed by trying to receive SSB for the same SSBRI while changing the Rx beam across multiple SSB bursts at the UE. An SS burst includes one or more SSBs, and an SS burst set includes one or more SSB bursts.

[0275] Quasi Co-Localization (QCL)

[0276] A UE may receive a list of up to M TCI state configurations to decode the PDSCH from a detected PDCCH carrying DCI intended for a given cell. M depends on the UE capabilities.

[0277] Each TCI state includes parameters for establishing a QCL relationship between one or more DL RSs and PDSCH DM-RS ports as described in Table 10. The QCL relationship is established using RRC parameters qcl-Type1 for the first DL RS and RRC parameters qcl-Type2 for the second DL RS (if configured).

[0278] The QCL type of each DL RS is given by the parameter "qcl-Type" included in QCL-Info and can have one of the following values:

[0279] - "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}

[0280] - "QCL-TypeB": {Doppler shift, Doppler spread}

[0281] - "QCL-TypeC": {Doppler shift, average delay}

[0282] - "QCL-TypeD": {spatial Rx parameters}

[0283] For example, if the target antenna port is for a specific NZP CSI-RS, the NZP CSI-RS antenna port may be indicated / configured to perform QCL with a specific TRS from the perspective of QCL-Type A or with a specific SSB from the perspective of QCL-Type D. Upon receiving the indication / configuration, the UE may receive the NZP CSI-RS using the Doppler value and delay value measured in the QCL-TypeA TRS, and apply the Rx beam for the received QCL-Type D SSB to receive the NZP CSI-RS.

[0284] *UL BM process

[0285] In the UL BM, beam reciprocity (or beam correspondence) between Tx and Rx beams may or may not be established according to the implementation of the UE. If Tx-Rx beam reciprocity is established at both the BS and the UE, the UL beam pair may be obtained from the DL beam pair. However, if Tx-Rx beam reciprocity is established neither at the BS nor at the UE, a process for determining the UL beam may be required that is separate from the determination of the DL beam pair.

[0286] Furthermore, even when both the BS and the UE maintain beam correspondence, the BS may apply the UL BM procedure to determine the DL Tx beam without requesting the UE to report its preferred beam.

[0287] UL BM may be performed based on beamformed UL SRS transmission. Whether to perform UL BM on an SRS resource set may be determined by using a parameter (RRC parameter). If the use is determined to be BM, only one SRS resource may be transmitted for each of multiple SRS resource sets at a given time.

[0288] The UE may be configured with one or more SRS resource sets (via RRC signaling), where one or more SRS resource sets are configured by SRS-ResourceSet (RRC parameter). For each SRS resource set, the UE may be configured with K ≥ 1 SRS resources, where K is a natural number and the maximum value of K is indicated by SRS_capability.

[0289] Similar to DL BM, the UL BM process can also be divided into Tx beam scanning at the UE and Rx beam scanning at the BS.

[0290] Fig. 20 An example of an SRS-based UL BM procedure is illustrated.

[0291] Fig. 20 (a) shows a process in which the BS determines the Rx beamforming, and Fig. 20 (b) shows the process of UE performing Tx beam scanning.

[0292] Fig.21 is a flow chart illustrating an example of an SRS-based UL BM procedure.

[0293] -The UE receives RRC signaling (e.g., SRS-Config IE) including a usage parameter (RRC parameter) set as BM from the BS (S2110). The SRS-Config IE is used to configure SRS transmission. The SRS-Config IE includes a list of SRS resources and a list of SRS resource sets. Each SRS resource set refers to a collection of SRS resources.

[0294] -The UE determines Tx beamforming of the SRS resource to be transmitted based on the SRS-SpatialRelation Info included in the SRS-Config IE (S2120). Here, the SRS-SpatialRelation Info is configured for each SRS resource and indicates whether the same beamforming as that for SSB, CSI-RS or SRS is applied for each SRS resource.

[0295] -If SRS-SpatialRelationInfo is configured for the SRS resource, the same beamforming as that for SSB, CSI-RS, or SRS is applied and transmitted. However, if SRS-SpatialRelationInfo is not configured for the SRS resource, the UE randomly determines Tx beamforming and transmits the SRS based on the determined Tx beamforming (S2130).

[0296] For P-SRS with "SRS-ResourceConfigType" set to "Periodic":

[0297] i) If SRS-SpatialRelationInfo is set to "SSB / PBCH", the UE transmits the corresponding SRS by applying the same spatial domain transmit filter as the spatial domain receive filter used to receive SSB / PBCH (or a spatial domain transmit filter generated from the spatial domain receive filter);

[0298] ii) if SRS-SpatialRelationInfo is set to "CSI-RS", the UE transmits the SRS by applying the same spatial domain transmit filter as that used to receive the CSI-RS; or

[0299] iii) If SRS-SpatialRelationInfo is set to 'SRS', the UE transmits the corresponding SRS by applying the same spatial domain transmit filter as that used to transmit the SRS.

[0300] - In addition, as in the following three cases, the UE may or may not receive feedback on the SRS from the BS (S2140).

[0301] i) When Spatial_Relation_Info is configured for all SRS resources in an SRS resource set, the UE transmits the SRS on the beam indicated by the BS. For example, if Spatial_Relation_Info indicates the same SSB, CRI, or SRI, the UE repeatedly transmits the SRS on the same beam.

[0302] ii) Spatial_Relation_Info cannot be configured for all SRS resources in an SRS resource set. In this case, the UE can transmit while randomly changing the SRS beamforming.

[0303] iii) Spatial_Relation_Info may be configured only for some SRS resources in an SRS resource set. In this case, the UE may transmit SRS on the beam indicated for the configured SRS resource, but for SRS resources for which Spatial_Relation_Info is not configured, the UE may perform transmission by applying random Tx beamforming.

[0304] Fig. 22 An exemplary directional LBT and an exemplary omnidirectional LBT are illustrated.

[0305] Fig. 22(a) illustrates a directional LBT including a specific beam direction LBT and / or a beam group unit LBT, and Fig. 22 (b) illustrates omnidirectional LBT.

[0306] Reference Fig. 22 (a), when a beam group consists of beams #1 to #5, performing LBT based on beams #1 to #5 can be referred to as beam group unit LBT. In addition, performing LBT by any one of beams #1 to #5 (e.g., beam #3) can be referred to as specific beam direction LBT. In this case, beams #1 to #5 can be continuous (or adjacent) beams, but can also be discontinuous (or non-adjacent) beams. In addition, the number of beams included in a beam group is not necessarily multiple, and a single beam can form a beam group.

[0307] Fig. 22 (b) illustrates omnidirectional LBT. When omnidirectional beams constitute one beam group and LBT is performed in units of the corresponding beam group, this can be interpreted as performing omnidirectional LBT. In other words, if beams in all directions (i.e., omnidirectional beams as a beam set covering a specific sector in a cell) are included in one beam group, this may mean omnidirectional LBT.

[0308] In the proposed method to be described later, a beam may mean an area where a specific operation (e.g., LBT or transmission) is performed by concentrating power in a specific direction and / or in a specific space. In other words, the UE or BS can perform operations such as LBT or transmission by aiming at a specific area (i.e., beam) corresponding to a specific space and / or a specific direction. Therefore, each beam may correspond to each space and / or each direction. In addition, the UE or BS may use a spatial domain filter corresponding to each space and / or each direction in order to use each beam. That is, one spatial domain filter may correspond to one or more beams. The UE or BS may perform operations such as LBT or transmission using a spatial domain filter corresponding to the beam (or space and / or direction) to be used.

[0309] For example, the UE or BS may perform LBT using a spatial domain filter corresponding to an LBT beam in the space and / or direction of the corresponding LBT beam, or perform DL / UL transmission using a spatial domain filter corresponding to a Tx beam in the space and / or direction of the corresponding Tx beam.

[0310] In high frequency bands of 52.6 GHz or higher, due to the relatively larger path loss than in low frequency bands, omnidirectional LBT (hereinafter, O-LBT) for performing LBT in all directions, omnidirectional transmission and reception, directional LBT (hereinafter, D-LBT) for performing LBT only in a specific beam direction, and directional transmission and reception by techniques such as analog beamforming using multiple antennas can be considered.

[0311] Accordingly, the BS needs to indicate to the UE the type of LBT to be used during UL signal / channel transmission and the direction in which the LBT will be performed. In the present disclosure, a method is described in which the BS configures the direction of the beam in which the LBT will be performed according to the mode of the UE. In other words, the present disclosure proposes a method for configuring the direction of the beam in which the LBT will be performed (hereinafter, the LBT beam) according to whether the UE is in idle / inactive mode or in connected mode.

[0312] A typical CAP performed for transmission in the U band is LBT. LBT is a mechanism for preventing collisions between transmissions by allowing the corresponding signal to be transmitted when the noise level is below a certain level as a result of comparing the surrounding interference level measured by the BS and / or UE to transmit the signal with a specific threshold such as an ED threshold.

[0313] In the case of high frequency bands, coverage may be limited due to significant path loss. To overcome this coverage problem, multiple antenna techniques may be used. For example, narrow beam transmission may be performed to transmit a signal by concentrating energy in a specific direction, rather than omnidirectional transmission.

[0314] In the high-frequency U-band, together with the above-mentioned CAP such as LBT, it is necessary to consider beam-based transmission in combination therewith. For example, in order to perform D-LBT in a specific direction, D-LBT can be performed only in the corresponding direction, or LBT can be performed as a group including the corresponding direction beam. Then, if it is determined that the channel is idle, transmission can be performed. Here, the beam group can include a single beam or multiple beams. If the beam group includes an omnidirectional beam, D-LBT can be extended to O-LBT.

[0315] Since the above-mentioned beam-based transmission transmits a signal by concentrating energy in a specific direction, the interference affecting the neighboring BS / UE (except for the nodes located in the transmission direction) can be relatively small compared to omnidirectional transmission. That is, it can be considered that spectrum sharing is naturally formed in beam-based transmission because beam-based transmission only causes interference in a specific direction. Therefore, if specific conditions are met, the channel access opportunity can be increased and the system performance can be improved by performing beam-based transmission without performing LBT.

[0316] Information about the beam group including each beam therein and information about at least one beam included in each beam group may be configured, and the CWS and backoff counter values ​​may be managed separately for each independent beam or each independent beam group. Therefore, when performing LBT, events such as CWS reset / increase or backoff counter reduction may affect each beam and the beam group including each beam. For example, if the feedback for data transmitted through LBT in a specific beam direction is NACK and thus the CWS value of the corresponding beam direction increases, the increase in the CWS value is also reflected in the CWS managed by the beam group including the corresponding beam, so that the CWS value of the beam group may increase. On the other hand, even if the CWS value of the corresponding beam direction increases, the CWS value of the beam group may be managed independently without affecting the beam group including the corresponding beam. In addition, the backoff counter value managed on a per-beam or per-beam group basis may also be configured as described above, so that the backoff counter value of each beam and the backoff counter value of each beam group are managed independently or according to each other, thereby affecting each other.

[0317] Beam-based LBT and beam-group-based LBT can be interchanged under specific conditions. In the case of UL transmission, the BS can indicate the LBT type to be used among the two LBT types (i.e., beam-based LBT and beam-group-based LBT). In the case of CG UL transmission, when configuring resources for CG UL transmission, the type of LBT to be performed on each resource can also be configured. If delay-sensitive data transmission is indicated together with LBT in a specific beam direction, data cannot be sent due to LBT failure. Therefore, channel access opportunities can be increased by allocating multiple LBT opportunities to other beams in the beam group including the corresponding beam.

[0318] In the present disclosure, a beam-based LBT process or a beam group-based LBT process may basically mean a Cat-3 or Cat-4 LBT based on random backoff. In beam-based LBT, energy measured by performing carrier sensing in a specific direction is compared with an ED threshold. Next, if the energy measured by performing carrier sensing is lower than the ED threshold, the channel in the corresponding beam direction may be considered idle, and if the energy measured by carrier sensing is higher than the ED threshold, the channel in the corresponding beam may be considered busy.

[0319] The beam group-based LBT process is to perform the above-mentioned LBT process in all beam directions included in the beam group, and perform a random backoff-based LBT process as a representative using the corresponding beam through multi-CC LBT similar to when a pre-configured / indicated beam in a specific direction (e.g., a representative beam) exists in the beam group, and perform Cat-1 or Cat-2 LBT based on non-random backoff on the remaining beams included in the beam group to send a signal when LBT succeeds. In the beam group-based LBT process, according to the regulations of each country / region, the random backoff-based LBT process may be performed through the representative beam, and LBT (no-LBT) may not be performed on the remaining beams included in the beam group to send a signal through each of the remaining beams.

[0320] Before describing the proposed method, the NR-based channel access scheme for the U-band to be used in the present disclosure is classified as follows.

[0321] - Category 1 (Cat-1): After a switching gap within the COT, the next transmission is immediately after the previous transmission, and the switching gap is shorter than 16us, including even the operating time of the transceiver. Cat-1 LBT can correspond to the above-mentioned Type 2 CCAP.

[0322] - Category 2 (Cat-2): LBT method without fallback. Once it is confirmed that the channel is idle during a specific time period shortly before transmission, the transmission can be performed immediately. Cat-2 LBT can be subdivided according to the length of the minimum sensing duration required for channel sensing just before transmission. For example, a Cat-2 LBT with a minimum sensing duration of 25us may correspond to the above-mentioned Type 2A CAP, and a Cat-2 LBT with a minimum sensing duration of 16us may correspond to the above-mentioned Type 2B CAP. The minimum sensing duration is merely exemplary, and a minimum sensing duration less than 25us or 16us (e.g., a minimum sensing duration of 9us) may also be available.

[0323] -Cat-3: LBT method based on fallback of fixed contention window size (CWS). The transmitting entity selects a random number N in the range of 0 to the (fixed) maximum CWS value and decrements the counter value whenever it determines that the channel is idle. When the counter value reaches 0, the transmitting entity is allowed to perform transmission.

[0324] -Category 4 (Cat-4): LBT method with variable CWS-based fallback. The transmitting entity selects a random number N in the range of 0 to a (variable) maximum CWS value and decrements the counter value whenever the channel is determined to be idle. When the counter value reaches 0, the transmitting entity is allowed to perform the transmission. If the transmitting entity receives feedback indicating a reception failure of the transmission, the transmitting entity increases the maximum CWS value by one level, selects a random number again within the increased CWS value, and performs the LBT process. Cat-4 LBT can correspond to the above-mentioned Type 1 CAP.

[0325] Furthermore, each proposed method, which will be described later, may be combined with other proposed methods and applied together unless each proposed method conflicts with other proposed methods.

[0326] The BS transmits information required when the UE (initially) accesses the corresponding cell through a synchronization signal (SS) / physical broadcast channel (PBCH) block (hereinafter, referred to as SSB). The SSB includes timing information such as the SS, the system frame number (SFN) and the most significant bit (MSB) of the SSB index, an SSB carrier offset value for physical resource block (PRB) grid alignment, a PDCCH configuration for subcarrier spacing and SIB1, RMSI CORESET / search space such as a demodulation reference signal (DMRS) type A position, information about the initial active DL BWP, and prohibition information.

[0327] Such an SSB is transmitted with a specific index by performing beam scanning at a determined time domain position. For example, the direction of the beam transmitted relative to the corresponding SSB index may be different. Before transmitting the PRACH for corresponding cell access (msgA in the case of 2-step RACH), the UE may select an SSB with the best receiving sensitivity among the SSBs received in each beam direction. Alternatively, the UE may select an SSB with a reference signal received power (RSRP) of a specific threshold or higher among the received SSBs.

[0328] When there is no SSB with RSRP of the threshold or higher, the UE may select an SSB to receive in any SSB direction and send PRACH (msgA in the case of 2-step RACH) in the direction associated with the RACH opportunity (RO) associated with the selected SSB index.

[0329] In an area where a spectrum sharing mechanism for channel access such as LBT in the U band is necessarily required, both the BS and the UE should perform transmission after confirming whether the channel is idle. A CAP such as the above-mentioned LBT is applied even to transmission of PRACH (or msgA).

[0330] Therefore, the UE should perform LBT before sending PRACH (or msgA). As described above, in a high frequency band of 52.6 GHz or higher, due to a relatively larger path loss than in a low frequency band, a technique such as analog beamforming using multiple antennas is used, and omnidirectional LBT (hereinafter, O-LBT) for performing LBT in all directions, omnidirectional transmission and reception, directional LBT (hereinafter, D-LBT) for performing LBT only in a specific beam direction, and directional transmission and reception can be considered.

[0331] In order for the UE to perform D-LBT in a specific beam direction, the beam direction in which LBT is to be performed should be previously configured / indicated by the BS. The BS may configure / indicate the direction of the beam in which LBT is to be performed differently depending on the mode of the UE. In other words, the BS may configure / indicate the direction of the beam in which LBT is to be performed (hereinafter, LBT beam) differently depending on whether the mode of the UE is an idle / inactive mode or a connected mode.

[0332] Fig.23 FIG. 2 shows an example of the Rx strength of the SSB signal in each Rx beam direction from the perspective of UE 1 and UE 2 when the BS sequentially transmits SSBs by performing beam scanning for each SSB index within a window of 5 ms with a 20 ms out-of-band period. Fig.23 , UE 1 and UE 2 may determine the SSB beam direction received with the highest Rx sensitivity as the best beam, and transmit PRACH or msgA in the corresponding beam direction in the RO to which the SSB beam is mapped. Fig.23 , UE1 can determine SSB index #2 as the best beam and send PRACH or msgA in the RO mapped to SSB index #2, and UE2 can determine SSB index #L as the best beam and send PRACH or msgA in the RO mapped to SSB index #L.

[0333] In addition, when beam reciprocity is established between a DL beam and a UL beam, a process for determining a DL beam pair or a process for determining a UL beam pair may be omitted. This may also be applied similarly even when beam correspondence is established.

[0334] Here, "establishing beam reciprocity (or beam correspondence)" may mean that in communication between a BS and a UE, it is assumed that a BS Tx beam is consistent with a BS Rx beam and a UE Tx beam is consistent with a UE Rx beam. Here, a BS Tx beam and a BS Rx beam may respectively mean a DL Tx beam and a DL Rx beam, and a UE Tx beam and a UE Rx beam may respectively mean a UL Tx beam and a UL Rx beam. Here, a Tx beam may mean a transmit beam, and an Rx beam may mean a receive beam.

[0335] The CCA area is an area used to evaluate whether a channel is occupied by the LBT procedure. If the energy measured relative to a specific Rx beam direction is higher than the energy detection (ED) threshold, the BS or UE can determine that the channel is busy, because this may mean that another BS or UE near the BS or UE is occupying the channel and is transmitting a signal. When the measured energy is lower than the ED threshold, the BS or UE can consider the channel to be idle, terminate the LBT process, and start the transmission of DL / UL signals / channels.

[0336] For the following reasons, it may be desirable to configure all DL signals / channels (or all UL signals / channels) included in one Tx burst as signals / channels having a spatial (partial) QCL relationship. Fig. 20 When, as illustrated in FIG. 1 , the BS transmits a Tx burst consisting of a total of 4 time slots after successfully performing LBT, the BS may transmit signals in 3 time slots in beam direction A and then transmit signals in the fourth time slot in beam direction C.

[0337] However, when the BS transmits a signal in beam direction A, the Wi-Fi AP coexisting in the corresponding U band may not be able to detect the signal transmitted in beam direction A and determine that the channel is idle. After successfully performing LBT, the Wi-Fi AP can start sending and receiving signals. In this case, if the BS transmits a signal in beam direction C starting from time slot #k+3, the signal may act as interference with the corresponding Wi-Fi signal. Therefore, when the BS that has already performed transmission in direction A performs transmission by switching the beam direction without additional LBT, the BS may cause interference with another coexisting wireless node. Therefore, it may be desirable not to switch the Tx beam direction of the Tx burst transmitted after the BS successfully performs LBT.

[0338] In the NR system, a method of signaling beam information to be used by the UE during UL transmission and reception by associating the DL signal with the UL signal is being considered. For example, if there is a beam direction generated by the UE on a channel state information reference signal (CSI-RS) resource by associating the CSI-RS resource with a sounding reference signal (SRS) resource, when the UE sends an SRS on an SRS resource linked to the CSI-RS resource (or when the UE signals a PUSCH scheduled by a UL grant of an SRS resource linked to the CSI-RS resource), the UE can use the Tx beam corresponding to the CSI-RS Rx beam to send a UL signal. In this case, the relationship between a specific Rx beam and a specific Tx beam can be configured by the UE when it is implemented when the UE has beam correspondence capability. Alternatively, the relationship between a specific Rx beam and a specific Tx beam can be configured through training of the BS and the UE when the UE does not have beam correspondence capability.

[0339] Therefore, when the association relationship between the DL signal and the UL signal is defined, COT sharing is allowed between a DL Tx burst consisting of a DL signal / channel that has a spatial (partial) QCL relationship with the DL signal and a UL Tx burst consisting of a UL signal / channel that has a spatial (partial) QCL relationship with the associated UL signal of the DL signal.

[0340] Here, the UL signal / channel may include at least one or more of the following signals / channels:

[0341] -SRS, Demodulation Reference Signal (DMRS) for PUCCH, DMRS for PUSCH, PUCCH, PUSCH, or PRACH

[0342] Here, the DL signal / channel may include at least one or more of the following signals / channels:

[0343] -PSS, SSS, DMRS for PBCH, PBCH, Tracking Reference Signal (TRS), CSI-RS for tracking, CSI-RS for CSI acquisition, CSI-RS for Radio Resource Management (RRM) measurement, CSI-RS for BM, DMRS for PDCCH, DMRS for PDSCH, PDCCH (or control resource set (CORESET) in which PDCCH can be transmitted), PDSCH, or a signal introduced for the purpose of tracking, (fine) time / frequency synchronization, coexistence, power saving, or arrangement of frequency reuse factor = 1 before a Tx burst, as a modified signal of the signals listed above or related signals or as a newly introduced signal.

[0344] Before describing the proposed method, an overall operation procedure of a UE and a BS for implementing the proposed method to be described later will now be described.

[0345] Fig.25 is a diagram for explaining an overall operation process of a UE according to at least one proposed method.

[0346] Reference Fig.25 , the UE may receive information related to the LBT from the BS (S2501). The information related to the LBT and a detailed method of receiving the information may be based on at least one of [Proposed Method #1], [Proposed Method #3], or [Proposed Method #5].

[0347] The UE may perform LBT for transmitting a UL signal based on the received information (S2503). If it is determined that the channel is idle as a result of performing LBT, the UE may transmit a UL signal (S2505). A detailed method of the UE transmitting a UL signal by performing LBT may be based on at least one of [Proposed Method #1], [Proposed Method #2], or [Proposed Method #4].

[0348] Fig.26 is a diagram for explaining an overall operation procedure of a BS according to at least one proposed method.

[0349] Reference Fig.26 , the BS may send information related to LBT to the UE (S2601). The information related to LBT and a detailed method of receiving the information may be based on at least one of [Proposed Method #1], [Proposed Method #3], or [Proposed Method #5].

[0350] The BS may receive a UL signal from the UE (S2603). The received UL signal may be transmitted based on at least one of [Proposed Method #1], [Proposed Method #2], and [Proposed Method #4].

[0351] Fig. 27 is a diagram for explaining the overall operation process of a network according to at least one proposed method.

[0352] The BS may transmit information related to the LBT (S2701). The information related to the LBT and a detailed method of transmitting the information may be based on at least one of [Proposed Method #1], [Proposed Method #3], or [Proposed Method #5].

[0353] The UE may perform LBT for transmitting a UL signal based on information received from the BS (S2703). If it is determined that the channel is idle as a result of performing LBT, the UE may transmit a UL signal to the BS (S2705). The method in which the UE transmits a UL signal by performing LBT may be based on at least one of [Proposed Method #2] or [Proposed Method #4].

[0354] [Proposed Method #1]

[0355] Method for configuring LBT beam for UE for initial access or UE in idle / inactive mode

[0356] 1. Implementation Method #1-1

[0357] The type of LBT to be used for a RACH procedure such as PRACH or msgA transmission may be configured through a higher layer signal such as a SIB (eg, a radio resource control (RRC) signal).

[0358] (1) In the initial access step before RRC connection, O-LBT may be used by default, and after RRC connection, the BS may configure / indicate to the UE whether O-LBT or D-LBT is to be used.

[0359] 2. Implementation Method #1-2

[0360] If beam correspondence is established, the UE can transmit PRACH or msgA after performing D-LBT in the Rx direction of the SSB beam. If beam correspondence is not established, the UE can transmit PRACH or msgA after performing D-LBT or O-LBT in units of beam groups.

[0361] 3. Implementation Methods #1-3

[0362] The UE may perform LBT and send PRACH or msgA according to the RSRP threshold configured to select the best beam direction as follows.

[0363] (1) Configuring a single SSB RSRP threshold

[0364] 1) The UE may perform D-LBT in the beam direction corresponding to the SSB in all ROs corresponding to all SSBs with an RSRP threshold or higher, and transmit PRACH or msgA in the beam direction in which D-LBT succeeds.

[0365] 2) Priority is configured for SSBs with an RSRP threshold or higher in a manner that assigns high priority to high Rx strength. The UE may attempt to perform D-LBT sequentially in ROs starting from the RO corresponding to the highest priority SSB, and send PRACH or msgA in the beam direction in which D-LBT succeeds. For example, the UE may attempt to perform D-LBT sequentially in ROs from the RO corresponding to the highest priority SSB to the RO corresponding to the lowest priority SSB, and send PRACH or msgA in the beam direction in which D-LBT succeeds first.

[0366] 3) After failing to perform D-LBT in all ROs corresponding to the SSB with the RSRP threshold or higher in 2) above, the UE may retry to perform D-LBT sequentially in ROs starting from the RO where D-LBT was first attempted, or may be switched to perform O-LBT to attempt to perform LBT. The UE may then send PRACH or msgA in the beam direction where LBT was successful.

[0367] (2) Configuring multiple RSRP thresholds (e.g., Th_1 and Th_2, Th_1>Th_2)

[0368] 1) When there are multiple SSBs with a first threshold (Th_1) or higher, the UE may select an arbitrary SSB from among the SSBs with Th_1 or higher, or select the highest priority SSB when a high priority is assigned to an SSB with high Rx strength. The UE may attempt to perform D-LBT only in the RO corresponding to the selected SSB. After failing to perform LBT, the UE may retry to perform D-LBT by reselecting the next highest priority SSB or an arbitrary SSB among the SSBs other than the previously selected SSB. The UE may send PRACH or msgA in the beam direction in which D-LBT succeeded.

[0369] 2) When there is no SSB with Th_1 or higher and only there is an SSB with a second threshold (Th_2) or higher, the UE may attempt to perform O-LBT in the RO corresponding to the SSB with Th_2 or higher, and after successfully performing O-LBT, the UE may send PRACH or msgA.

[0370] 4. Implementation Methods #1-4

[0371] In the case of contention-free random access (CFRA) triggered by the BS's scheduling (e.g., PDCCH order) in the UE's connected mode, the UE can perform D-LBT with respect to the RO and dedicated preamble indicated to the UE. In contrast, in the case of contention-based random access (CBRA) such as the UE's idle / inactive mode, the UE can always perform O-LBT.

[0372] Here, in [Proposed Method #1], a single LBT beam can also be mapped to multiple UL Tx beams.

[0373] Hereinafter, [Proposed Method #1] will be described in more detail.

[0374] As described above, in order to access a channel in the U band, both the UE and the BS should perform LBT in an area where a spectrum sharing mechanism such as LBT is mandatory before transmission. In order to initially access the BS, the UE can receive SSBs scanned in different beam directions to obtain basic information of the cell and RACH-related information (e.g., RACH configuration). In addition, the UE can select an SSB with high Rx strength (or RSRP) (e.g., an SSB exceeding the RSRP threshold) from the received SSBs or select an arbitrary SSB. The UE can send PRACH or msgA in the RO and beam direction associated with the selected SSB index. In order to send a UL signal in the direction associated with the selected SSB, the UE should successfully perform D-LBT or O-LBT in the corresponding direction.

[0375] In this case, the BS may be configured to transmit the type of LBT for PRACH or msgA used by the UE to attempt initial access through a higher layer signal such as SIB (e.g., RRC signal). For example, when the BS broadcasts RACH related information through SIB1, if the type of LBT to be used in RO is configured as O-LBT, the UE will perform O-LBT in a manner similar to Rel-16 NR-U, and if O-LBT is successful, the UE will transmit PRACH or msgA.

[0376] As another example, if the BS indicates D-LBT through SIB1, the UE may select an SSB exceeding the RSRP threshold from among the SSBs received in multiple beam directions, or select an arbitrary SSB. The UE may perform D-LBT on the RO and beam direction associated with the selected SSB index, and if D-LBT is successful, the UE may send PRACH or msgA.

[0377] Alternatively, before an RRC connection such as initial access, the UE may unconditionally use O-LBT to send a UL signal by default, and after the RRC connection, the BS may configure whether to continuously perform O-LBT or switch to D-LBT.

[0378] Beam correspondence may mean that in the communication between the BS and the UE, it is assumed that the BS Tx beam is consistent with the BS Rx beam and the UE Tx beam is consistent with the UE Rx beam. Here, the BS Tx beam and the BS Rx beam may respectively mean the DL Tx beam and the DL Rx beam, and the UE Tx beam and the UE Rx beam may respectively mean the UL Tx beam and the UL Rx beam.

[0379] When the UE receives SSBs (with different indices) broadcast and transmitted in multiple beam directions for initial access, if the UE's SSB Rx beam and the UE's PRACH or msgA Tx beam are consistent (i.e., beam correspondence is established), the UE can perform D-LBT in the same Tx beam as the SSB beam Rx direction, and if D-LBT is successful, the UE can send PRACH or msgA.

[0380] If the UE's SSB Rx beam is inconsistent with the UE's PRACH or msgA Tx beam (i.e., beam correspondence is not established), the UE may perform O-LBT before sending PRACH or msgA. This is because, since performing O-LBT means that beam correspondence is not established, performing transmission and D-LBT in a specific beam direction has no significant advantage to a meaningful extent compared to performing transmission and O-LBT in all directions, and if beam correspondence is not established, it is difficult for the UE to accurately determine the direction in which D-LBT will be performed.

[0381] The UE for initial access may compare the RSRP of the SSB received in the corresponding beam direction with the RSRP threshold configured by the BS and select the SSB with the RSRP threshold or higher as the optimal beam direction.

[0382] However, there may be multiple SSBs with an RSRP threshold or higher. The UE may then select an arbitrary SSB from among the SSBs with an RSRP threshold or higher. The UE may attempt to perform D-LBT on the RO and beam direction associated with the selected SSB index. Alternatively, the UE may attempt to perform D-LBT in descending order by configuring a priority starting with the SSB with the highest Rx strength, or may attempt to perform D-LBT in directions corresponding to all ROs associated with all SSBs with an RSRP threshold or higher.

[0383] However, even when a single RSRP threshold is configured for the UE and there are multiple SSBs exceeding the RSRP threshold, if the UE arbitrarily selects only one SSB among the SSBs having the RSRP threshold or higher or selects the SSB with the maximum Rx strength and attempts to perform D-LBT in the RO and beam direction corresponding to the selected SSB, the UE's channel access opportunity may be low due to the possibility of LBT failure. That is, the UE's PRACH or msgA transmission opportunity may be relatively low.

[0384] Accordingly, as in (1) of implementation #1-3, the UE may attempt to perform D-LBT in the corresponding beam directions corresponding to all ROs associated with all SSBs with an RSRP threshold or higher configured for the UE. The UE may send PRACH or msgA in the beam direction where D-LBT is successful, thereby increasing channel access opportunities.

[0385] Alternatively, the UE may configure priorities in order of SSB Rx strength and attempt to perform D-LBT sequentially in ROs and beam directions starting from the RO and beam direction corresponding to the SSB with the highest priority (e.g., the SSB with the maximum RSRP) to the RO and beam direction corresponding to the SSB with the lowest priority (e.g., the SSB with the minimum RSRP). If all related D-LBTs fail as a result of attempting to perform D-LBT in all ROs corresponding to SSBs with an RSRP threshold or higher according to 1) or 2) of (1) of implementation #1-3, the UE may retry performing D-LBT in ROs starting from the RO in which D-LBT was first attempted, or switch to O-LBT to attempt to perform O-LBT. If LBT is successful, the UE may send PRACH or msgA.

[0386] If multiple RSRP thresholds are configured, the UE may select an arbitrary SSB from among the SSBs having Th_1 or higher, or select the highest priority SSB when the priority of the SSB is configured according to the Rx strength as in 1) or 2) of (2) of implementation #1-3. In this case, if the UE fails to perform D-LBT as a result of attempting to perform D-LBT only in the RO corresponding to the selected SSB, the UE may reselect the next highest priority SSB or an arbitrary SSB from among the SSBs other than the previously selected SSB, and retry to perform D-LBT. The UE may send PRACH or msgA in the beam direction in which D-LBT succeeded.

[0387] When there is no SSB with Th_1 or greater and only there is an SSB with Th_2 or greater, the UE may attempt to perform O-LBT in the RO corresponding to the SSB with Th_2 or greater, and after successfully performing O-LBT, the UE may transmit PRACH or msgA.

[0388] Unlike the initial access of a UE in idle mode, a UE in connected mode may transmit PRACH or msgA based on CFRA triggered by scheduling (e.g., PDCCH order) of the BS. In this case, the UE may perform D-LBT on the RO and dedicated preamble indicated to the UE to transmit PRACH or msgA. In the case of CBRA in a UE in idle / inactive mode, the UE may always perform O-LBT.

[0389] [Proposed Method #2]

[0390] Method for configuring UL LBT (failure) counter value in performing D-LBT or O-LBT for UL transmission

[0391] 1. Implementation Method #2-1

[0392] The UE can manage and apply the UL LBT (failure) counter value with respect to each beam. For example, when D-LBT in a specific direction fails continuously so that the counter value reaches the maximum value M1, the UE can reselect the LBT beam and retry to perform D-LBT based on the reselected LBT beam. Here, the value M1 can be predefined by the standard or can be configured / indicated by the BS.

[0393] 2. Implementation method #2-2

[0394] The UE can manage and apply the UL LBT (failure) counter value with respect to each beam. For example, when D-LBT in a specific direction fails continuously so that the counter value reaches the maximum value, the UE can switch to O-LBT and attempt to perform O-LBT. The UE can send information indicating switching to O-LBT or falling back to O-LBT to the BS through a specific signal / channel. Here, the counter value of O-LBT and the counter value of D-LBT for each beam can be managed and applied independently.

[0395] (1) In order to inform the BS that the UE has switched to O-LBT, the UE may directly send relevant information through the PUSCH. Alternatively, the UE may inform the BS that the UE has switched to O-LBT by performing UL transmission using a pre-scheduled / pre-configured specific time-frequency resource. For example, when the UE switches to O-LBT, if the BS pre-configures the time-frequency resources to be used for the UE, the UE may perform the first UL transmission on the corresponding time-frequency resources after switching to O-LBT.

[0396] 3. Implementation Method #2-3

[0397] While the UE performs a beam reselection operation as in embodiment #2-1, when the counter value reaches a maximum value M2 due to continuous failure of D-LBT with respect to multiple beams, the UE may perform the following process. In other words, when the counter values ​​of N beams all reach the value M1 or the sum of the counter values ​​of the beams reaches the value M2, the following process may be performed. Here, N and M2 may be predefined by the standard or may be configured / indicated by the BS.

[0398] (1) When the UE has performed an initial access procedure in idle mode, the UE may perform cell reselection.

[0399] (2) When the UE is already in connected mode and there is another UL BWP configured besides the current active UL BWP, the UE may switch from the active UL BWP to the other UL BWP.

[0400] Here, a single LBT beam in [Proposed Method #2] can be mapped to multiple UL Tx beams.

[0401] Hereinafter, [Proposed Method #2] will be described in more detail.

[0402] In the U band, the UE cannot perform transmission due to continuous failure of LBT. If the UE cannot perform LBT all the time, ambiguity may occur between the UE and the BS. Therefore, in Rel-16 NR-U, a UL LBT (failure) counter is configured, and it has been stipulated that when the counter value reaches a specific maximum value by increasing the counter value every time UL LBT fails, the UL BWP is switched.

[0403] However, unlike the 6-GHz NR-U that always performs only O-LBT, D-LBT and transmission and reception in a specific beam direction can also be supported together with O-LBT in high frequency bands above 52.6 GHz. Therefore, when D-LBT is performed in the RACH process to send PRACH or msgA, the UL LBT (failure) counter that has been managed and applied to O-LBT can be defined with respect to each direction in which D-LBT is attempted, and can be managed and applied to each direction separately.

[0404] For example, the UL LBT (failure) counter value may be preconfigured with respect to a specific beam direction. For example, when as many counter values ​​as the number of beam directions in which the corresponding SSBs are transmitted are defined and the counter values ​​are managed independently for the corresponding beam directions, each time the UE attempts to perform D-LBT for transmitting PRACH or msgA in the RO associated with each SSB, the counter value associated with the corresponding direction may be applied (increased or decreased).

[0405] If D-LBT performed in a specific beam direction fails continuously so that the counter value reaches the maximum value M1, the UE may select an SSB received in another beam direction and perform LBT beam reselection to retry D-LBT in the RO corresponding to the selected SSB, which is different from the case of performing BWP switching for O-LBT in Rel-16 NR-U. In this case, the counter value of the reselected beam direction can be managed and applied independently of the counter value of the previous direction.

[0406] Here, the M1 value, which is the maximum value of the counter for each beam direction, is a value that can be predefined by the standard or configured / indicated by the BS. In addition, the M1 value can be configured differently for each beam direction. For example, the maximum value of the beam direction with the highest RSRP threshold of the SSB can be configured to be greater than the maximum values ​​of other beam directions. In other words, the maximum value of each beam direction can be configured differently according to the RSRP threshold of the SSB, and can be configured to be larger as the RSRP threshold of the SSB increases.

[0407] Alternatively, as in embodiment #2-2, when UL LBT is managed for each beam and a UL LBT (failure) counter value is applied to each beam and the counter value reaches a maximum value due to continuous failure of D-LBT in a specific beam direction, the UE may retry to perform LBT by switching from D-LBT to O-LBT. Here, the counter value of O-LBT may also be managed and applied independently of the counter value of each beam relative to D-LBT.

[0408] In addition, the reason for performing D-LBT is that there is no significant advantage to performing transmission and D-LBT in a specific direction compared to performing transmission and O-LBT in all directions to a meaningful extent, and due to the continuous failure of D-LBT, it is difficult for the UE to accurately determine the direction in which D-LBT will be performed.

[0409] However, if LBT in multiple beam directions fails continuously, BWP switching must be performed as in the UL LBT failure procedure of the conventional NR-U. Therefore, when the UE performs a beam reselection operation as in implementation #2-1, if the counter value reaches the M2 value due to continuous failure of D-LBT for multiple beams, UL BWP switching may be triggered according to the UL LBT failure procedure of Rel-16 NR-U. In addition, the case where the counter value reaches the M2 value may mean, for example, the case where the counter values ​​of N beams all reach the M1 value or the sum of the counter values ​​of the corresponding beams reaches the M2 value. Here, the N value and the M2 value may be predefined according to the standard, or may be configured / indicated by the BS.

[0410] [Proposed Method #3]

[0411] A method of configuring / indicating an LBT beam for / to a UE in connected mode will now be described.

[0412] 1. Implementation Method #3-1

[0413] When configuring a UL Tx beam for a UE, the configuration of an LBT beam may also be included together with the configuration of the UL Tx beam. For example, the BS may configure a UL Tx beam and an LBT beam for a UE through space-related information.

[0414] (1) If the configuration of the LBT beam is not included in the configuration information such as the space-related information, the LBT beam may be configured by default to be the same as the UL Tx beam. For example, if the beam correspondence is established between the Rx beam and the Tx beam of the UE, the BS may not include the configuration information of the LBT beam, and may only include the configuration information of the UL Tx beam and send the configuration of the UL Tx beam to the UE. In other words, when the beam correspondence is established between the Rx beam and the Tx beam of the UE, the BS may only send the configuration information of the UL Tx beam to the UE, without sending the configuration information of the LBT beam separately.

[0415] In this case, the UE can configure the same beam as the UL Tx beam as an LBT beam and perform LBT based on the LBT beam.

[0416] For example, the configuration of the UL Tx beam sent by the BS can be transmission configuration indication (TCI) information or SRS resource indicator (SRI), and the UE can configure an LBT beam in the same direction as the direction of the UL Tx beam obtained through the TCI information or SRI.

[0417] (2) The LBT beam can be configured by signaling that is independent of the configuration of the UL Tx beam. For example, the LBT beam and the UL Tx beam can be configured separately by a high-layer signal such as an RRC signal, a physical layer signal such as a downlink control information (DCI), or a specific signal / channel.

[0418] (1) of Implementation #3-1 may be an exception to Implementation #3-1. In other words, if the beam correspondence of the UE is established, the UE can acquire the DL Rx beam based on the UL Tx beam even when only the UL Tx beam is configured for the UE. In this case, the same beam as the UL Tx beam can be used as the LBT beam. Therefore, if the BS recognizes that the beam correspondence of the UE is established through the UE's capability report, the signaling overhead for configuring the LBT beam can be reduced by performing configuration only for the UL Tx beam.

[0419] For example, if the BS recognizes that the beam correspondence of the UE is established, it is not necessary to include information for configuring the LBT beam in the spatial related information or in the joint TCI state, or it is not necessary to include the configuration of the additional RS for indicating the LBT beam in the RS indicated by the spatial related information or the joint TCI state. Therefore, since there is no need to perform the transmission of a separate signal for indicating / configuring the LBT beam, the signaling bit size can be reduced. As another example, if the BS recognizes that the beam correspondence of the UE is established, since there is no need to perform the transmission of a separate signal for indicating / configuring the LBT beam, the signaling overhead is reduced. As a result, the decoding complexity of the UE can be reduced. This is because, if the UE informs the BS that the beam correspondence is established, the UE expects to receive only information about the UL Tx beam and only needs to select the same beam as the UL Tx beam as the LBT beam.

[0420] 2. Implementation Method #3-2

[0421] An LBT beam for a specific beam direction may be preconfigured by a high-layer signal such as an RRC signal, and when a UL signal is scheduled for a UE, an LBT beam aligned with the UL Tx beam direction may be indicated. For example, a specific number of LBT beams such as four beams obtained by dividing all directions into four may be preconfigured. Among the four beams, an LBT beam aligned with the UL Tx beam is configured for the UE / or indicated to the UE by the BS. As another example, N LBT beams obtained by dividing all directions into N may be preconfigured for the UE. Among the N beams, the UE may perform LBT using an LBT beam that covers the UL Tx beam indicated to the UE / configured for the UE.

[0422] 3. Implementation Method #3-3

[0423] It can be done by considering that multiple beams included in the CCA area can be multiplexed to configure an SSB-based beam instead of a channel state information reference signal (CSI-RS)-based beam after the UE performs D-LBT using an LBT beam in a specific beam direction.

[0424] Here, in [Proposed Method #3], a single LBT beam can be mapped to multiple UL Tx beams.

[0425] Hereinafter, [Proposed Method #3] will be described in more detail.

[0426] For a UE in connected mode that performs UL transmission using resources scheduled or configured by a BS, a spatial relationship with a reference RS for each of UL channels / signals such as PUCCH / PUSCH / SRS can be configured by using an information element (IE) such as spatial-related information in a higher-layer signal such as an RRC signal.

[0427] In order to perform D-LBT in the U band, the spatial relationship with the LBT beam can also be configured together with the spatial relationship with the reference RS for the UL Tx beam. The spatial relationship with the LBT beam can be configured to be included in the same IE as PUCCH / PUSCH / SRS. Alternatively, the spatial relationship with the LBT beam can be configured by separate signaling (e.g., high-layer signaling or DCI) for PUCCH / PUSCH / SRS from the IE.

[0428] When the spatial relationship with the LBT beam is not configured through the same IE as PUCCH / PUSCH / SRS or through separate signaling, the LBT beam can be configured by default to be the same as the UL Tx beam. That is, when the spatial relationship with the LBT beam is not configured, the UE can select the same beam as the UL Tx beam as the LBT beam based on the spatial relationship with the UL Tx beam.

[0429] For example, when the BS recognizes that the UE's beam correspondence is established through the UE's capability report, the BS may not configure the spatial relationship with the LBT beam for the UE. If the spatial relationship with the LBT beam is not configured, the UE may configure the same beam as the UL Tx beam as the LBT beam.

[0430] Here, configuring the same beam as the UL Tx beam as the LBT beam means that the spatial relationship with the reference RS configured for the UL Tx beam for each UL signal / channel is also applied to the LBT beam. For example, information related to the SRI or TCI configured for the UL Tx beam can be equally applied to the LBT beam.

[0431] When the LBT beam is configured by signaling separate from the UL Tx beam configuration, the LBT beam may be configured by a higher layer signal such as an RRC signal, a physical layer signal such as a DCI, or a specific signal / channel.

[0432] Alternatively, the BS may pre-configure an LBT beam of a corresponding specific beam direction for the UE through a high-layer signal such as an RRC signal, and when scheduling a UL signal for the UE, the BS may indicate an LBT beam aligned with the UL Tx beam direction. For example, four beams obtained by dividing all directions into four may be pre-configured through a high-layer signal. The BS may indicate the direction of one of the four beams to the UE. As another example, N LBT beams obtained by dividing all directions into N may be pre-configured for the UE. Among the N beams, the UE may perform LBT using an LBT beam that covers the UL Tx beam indicated to / configured for the UE.

[0433] The beamwidth having a spatial relationship with a specific reference RS may be relatively narrow compared to the beamwidth of a beam having a spatial relationship with an SSB.

[0434] For example, the beam width configured by SSB can be wider than the beam width configured by a specific RS such as CSI-RS. The area affected by the direction of the UL Tx beam and the transmission by the Tx beam can be included in the CCA area using the LBT beam as desired. That is, since the UL Tx beam outside the CCA area using the LBT beam cannot be allowed, when the LBT beam is relatively narrow, it may be difficult to multiplex the UL Tx beams in other directions outside the LBT beam by time division multiplexing (TDM) or space division multiplexing (SDM). Therefore, the BS can perform D-LBT using the LBT beam in a specific beam direction, and then configure the LBT beam only based on SSB rather than CSI-RS by considering that multiple beams included in the CCA area can be multiplexed.

[0435] [Proposed Method #4]

[0436] Hereinafter, a method of increasing a channel access opportunity of a UE will be described.

[0437] 1. Implementation Method #4-1

[0438] When the BS configures the LBT beam for the UE, multiple LBT beams can be configured / indicated. For example, if the number of configured / indicated LBT beams is 2, the main LBT beam and the auxiliary LBT beam can be configured / indicated according to the priority.

[0439] (1) When the UE cannot perform D-LBT using the primary LBT beam, the UE may attempt to perform D-LBT multiple times through another pre-configured LBT beam (e.g., a secondary LBT beam).

[0440] (2) When only one LBT beam (e.g., a main LBT beam) is configured for a UE to perform D-LBT, if the UE cannot perform D-LBT using the LBT beam, the UE may retry performing LBT by falling back or switching to O-LBT.

[0441] In this case, only one LBT beam may be configured for the UE. When the UE cannot perform D-LBT using the LBT beam, the UE may perform O-LBT.

[0442] (3) If the channel is determined to be busy in M ​​CCA slots during the fallback process when the UE performs D-LBT using the primary LBT beam, the UE may fallback / switch to the secondary LBT beam or O-LBT.

[0443] 2. Implementation Method #4-2

[0444] As a 2-step LBT method, when the main LBT beam is a relatively wide beam (e.g., an SSB-based LBT beam) and the auxiliary LBT beam is a relatively narrow beam (e.g., a CSI-RS-based LBT beam), if the UE cannot perform D-LBT using the main LBT beam, the UE may retry performing D-LBT using the auxiliary LBT beam. In this case, the auxiliary LBT beam may be included in the main LBT beam. That is, the main LBT beam may be an LBT beam covering the auxiliary LBT beam.

[0445] 3. Implementation Method #4-3

[0446] The BS may configure multiple candidate LBT beams for the UE. In this case, since it may be a burden for the BS to monitor all multiple candidate LBT beams at the same time, the UE may inform the BS through a specific channel / signal of information about the actual use of the multiple candidate LBT beams configured by the BS or a specific LBT beam or a specific LBT beam direction to be used by the UE.

[0447] (1) A specific channel / signal may be pre-configured / indicated by the BS. For example, the specific channel / signal may be a specific sequence mapped to each LBT beam, or may be a UL channel / signal (e.g., SRS or SR) transmitted on a pre-configured time-frequency resource.

[0448] 4. Implementation Method #4-4

[0449] When an LBT beam is pre-configured by the BS for a UE in association with a specific RS, if the Rx performance of the associated RS is degraded, the UE may attempt to perform D-LBT through another pre-configured LBT beam (e.g., another LBT beam associated with another RS). For example, when a primary LBT beam is configured in association with an SSB (or CSI-RS) and a secondary LBT beam is configured in association with a CSI-RS (or SSB), if the Rx performance of the SSB (or CSI-RS) is degraded, the UE may attempt to perform D-LBT using the secondary LBT beam.

[0450] As another example, when the primary LBT beam is associated with a first CSI-RS (or first SSB) and the secondary LBT beam is associated with a second CSI-RS (or second SSB), if the Rx performance of the first CSI-RS (or first SSB) is degraded, the UE may attempt to perform D-LBT using the secondary LBT beam.

[0451] In the above case, the beamwidth of the LBT beam associated with the SSB may be wider than the beamwidth of the LBT beam associated with the CSI-RS. In addition, the beamwidth of the LBT beam associated with the first CSI-RS (or the first SSB) may be wider than the LBT beam associated with the second CSI-RS (or the second SSB). However, conversely, the beamwidth of the LBT beam associated with the first CSI-RS (or the first SSB) may be narrower than the LBT beam associated with the second CSI-RS (or the second SSB).

[0452] In addition, the main LBT beam and the auxiliary LBT beam can be LBT beams for different directions. In contrast, any one of the main LBT beam and the auxiliary LBT beam can cover another LBT beam.

[0453] Hereinafter, [Proposed Method #4] will be described in more detail.

[0454] There is always a possibility of failure for LBT for transmission in the U-band. Specifically, if there is continuous interference in a specific beam direction, LBT may fail repeatedly. In this case, if the UE continuously attempts to perform LBT using the same LBT beam, since the UE cannot send the scheduled UL signal / channel before LBT succeeds, from the BS's point of view, ambiguity may arise as to whether the UE has not received the UL scheduling or cannot perform LBT.

[0455] Therefore, considering the possibility of consecutive LBT failures in a specific beam direction, multiple LBT beams may be configured when the LBT beams are configured for the first time.

[0456] The BS may configure multiple LBT beams for the UE. For example, a specific beam direction may be configured as a main LBT beam. For example, a beam direction having the best Rx sensitivity for the RS with which the LBT beam has a spatial relationship may be configured as a main LBT beam.

[0457] Auxiliary LBT beams and / or a third LBT beam may also be configured for the UE based on the number of configured candidate LBT beams and the Rx sensitivity of the RS. In this case, when the UE cannot perform D-LBT using the main LBT beam, the UE may attempt to perform LBT multiple times using other pre-configured LBT beams. For example, when the BS indicates LBT beams 1, 2, and 3 to the UE at the same time and S=k is indicated as the start and length indicator value (SLIV), the UE may attempt to perform D-LBT using beam 1 used in the kth symbol. If D-LBT based on beam 1 fails, the UE may attempt to perform D-LBT using beam 2 in the k+1 symbol, and if D-LBT using beam 2 also fails, the UE may retry to perform D-LBT using beam 3 in the k+2 symbol, thereby increasing channel access opportunities.

[0458] This is because, since falling back to O-LBT means that beam correspondence is not established, there is no significant advantage to performing transmission and D-LBT in a specific beam direction compared to performing transmission and LBT in all directions to a meaningful extent, and it is difficult for the UE to accurately determine the direction in which D-LBT is to be performed.

[0459] Alternatively, as a 2-step method, the UE may perform D-LBT based on a relatively wide beam as a main LBT beam, and after failing to perform D-LBT, the UE may retry to perform D-LBT using a secondary LBT beam which is a narrow beam included in the main LBT beam, thereby increasing channel access opportunities.

[0460] In this case, the area affected by the direction of the Tx beam and the transmission through the Tx beam should be included in the CCA area using the LBT beam. When D-LBT is performed through a wide beam and D-LBT is performed through a narrow beam, the ED threshold may be configured differently.

[0461] As described above, when multiple candidate LBT beams are configured, simultaneously monitoring all of the configured multiple candidate LBT beams can become a burden for the BS. Therefore, the UE can select the beam direction of the candidate LBT beam with the best Rx sensitivity of the RS among the candidate LBT beams configured for the UE as the LBT beam, and inform the BS of the selected LBT beam or the beam direction of the candidate LBT beam through a specific channel / signal. The specific channel / signal can be a specific sequence previously mapped to each LBT beam, or can be a UL channel / signal (e.g., SRS or SR) sent on a pre-configured time-frequency resource.

[0462] When the Rx performance of the associated RS is degraded based on the BS's pre-configuration of the LBT beam associated with a specific RS, the UE may attempt to perform D-LBT after switching to another pre-configured LBT beam (e.g., another LBT beam pre-associated with another RS).

[0463] [Proposed Method #5]

[0464] The BS may configure / indicate the channel access mode for each RACH-related signal / channel or each RO through cell-common signaling, UE-specific signaling, or a combination thereof.

[0465] 1. Implementation Method #5-1

[0466] The BS may configure / indicate through cell common signaling (eg, SIB1) that the no-LBT mode is applicable to all or part of the RACH related signals / channels.

[0467] (1) The BS may configure / indicate, through UE-specific signaling (eg, dedicated RRC signaling), that the no-LBT mode is applicable to all or part of RACH-related signals / channels only for / to one or more specific UEs.

[0468] 2. Implementation Method #5-2

[0469] The BS may configure / indicate through cell common signaling (eg, SIB1) that the no-LBT mode is applicable to all or part of the RACH-related signals / channels transmitted in a specific RO.

[0470] (1) The BS may configure / indicate, through UE-specific signaling (eg, dedicated RRC signaling), only for / to one or more specific UEs that the no-LBT mode is applicable to all or part of the RACH-related signals / channels transmitted in a specific RO.

[0471] In the above description, (1) of embodiment #5-1 and (1) of embodiment #5-2 can be applied to active BWPs other than the initial BWP after initial access. The constraint condition of the duty cycle can be configured / indicated for the signal / channel sent based on the no-LBT mode. Alternatively, if the constraint condition of the duty cycle of the signal / channel sent based on the O-LBT mode is previously indicated, (1) of embodiment #5-1 and (1) of embodiment #5-2 can be applied to the signal / channel that satisfies the condition of the duty cycle based on the condition of the duty cycle defined by the determination of the UE even without additional indication / configuration to determine whether to apply the no-LBT mode.

[0472] Hereinafter, [Proposed Method #5] will be described in more detail.

[0473] For fair coexistence between different RATs in the U band, it may be necessary to perform an appropriate spectrum sharing mechanism (e.g., LBT) before transmission. However, the spectrum sharing mechanism may be mandatory or may not be mandatory for each region / country regulation requirement. Therefore, in a specific region / country, a no-LBT mode in which transmission is performed without LBT according to regulations may be applicable.

[0474] Specifically, since RACH-related signals / channels are basic signals / channels for first cell access or synchronization, if LBT is always applied before transmission, several disadvantages such as delay in cell access due to reduced channel access opportunities for UE may occur.

[0475] Therefore, in regions / countries where spectrum sharing mechanisms such as LBT are not mandatory in regulations, a no-LBT mode in which a channel can be accessed without LBT before transmission may be useful. Specifically, the no-LBT mode may be beneficial for RACH-related signals / channels. In addition, in order to prevent congestion situations such as frequent transmission conflicts when a high-density UE in a cell always performs transmission using the no-LBT mode, a duty cycle constraint may be required to limit the ratio of the time occupied by a signal transmitted in the no-LBT mode within a specific duration.

[0476] The UE for initial access receives information about the corresponding cell and RACH configuration through the cell common signaling broadcast by the BS, and performs the RACH process based on the received information about the cell and the received RACH configuration. In this case, the BS can indicate that the no-LBT mode can be applied to part or all of the RACH-related signals / channels based on the prescribed cell common signaling such as SIB1. After receiving the information about the application of the no-LBT mode, the UE may not perform LBT on the signals / channels applicable to the no-LBT mode among the RACH-related signals / channels (e.g., Msg1, Msg3, and MsgA), thereby quickly performing transmission. Whether the no-LBT mode is applicable to Msg3 can be included in Msg2 that schedules Msg3.

[0477] A signal / channel related to the RACH procedure is an important signal / channel used when synchronization between a BS and a UE is not aligned and when initial access is performed.

[0478] Therefore, when each UE receives a RACH configuration for an active BWP other than the initial BWP through dedicated RRC signaling after initial access, a signal / channel to which no-LBT can be applied can also be configured / indicated. The UE can immediately perform transmission without LBT with respect to all or part of the RACH-related signals / channels to which no-LBT is applied based on the information about whether no-LBT is applied.

[0479] RO related information may be included in the information publicly broadcast by the BS for the UE initial access. In this case, whether no-LBT is applicable may be configured for each RO. For example, if a total of N ROs are configured in the RACH time slot in the time domain, the no-LBT mode may be applied to the first RO, the last RO, or the even-numbered / odd-numbered RO among the N ROs, so that the signal / channel sent in the corresponding RO may be configured to be sent without performing LBT.

[0480] Alternatively, when there are a total of M ROs in the frequency domain, the RACH-related signal / channel may be configured to be transmitted without performing LBT in ROs of a specific frequency band or in ROs of a specific order.

[0481] As described above, since the signals / channels related to the RACH process are not always used only for initial access, the no-LBT mode can be UE-specifically configured for each UE or indicated to each UE through dedicated RRC signaling to apply to signals / channels sent in a specific RO.

[0482] If there is a high density of UEs in the cell, so that there are frequent conflicts between signals sent in no-LBT mode, a large number of retransmissions are required and the efficiency may be reduced. Therefore, constraints such as duty cycle may be additionally imposed on the signals / channels sent in no-LBT mode.

[0483] Alternatively, if the duty cycle constraint condition is pre-configured, the UE can determine whether to apply no-LBT through the UE's determination without additional indication / configuration, and apply no-LBT to the signal / channel that meets the constraint condition. For example, in an observation period of 100ms, the time occupied by the signal / channel sent in the no-LBT mode can be configured / indicated by the BS to not exceed 10ms. Alternatively, the duty cycle constraint condition is pre-configured, and the signal / channel that meets the condition can be configured / indicated to the UE to perform transmission without LBT.

[0484] The above description of the present disclosure is not limited to device-to-device communication, and may be used on UL or DL. In this case, the BS or the relay node may use the above proposed method.

[0485] Since the example of the above-mentioned proposed method can be included in one of the implementation methods of the present disclosure, it is obvious that the example can be regarded as a proposed method. Although the above-mentioned proposed method can be implemented independently, the proposed method can also be implemented in a combined (integrated) form of parts of the proposed method. A rule can be defined so that information about whether to apply the proposed method (or information about the rule of the proposed method) is indicated by a BS to a UE or by a Tx UE to an Rx UE through a predefined signal (e.g., a physical layer signal or a high-layer signal).

[0486] The various descriptions, functions, processes, proposals, methods and / or operational flowcharts of the present disclosure described herein may be applied to, but not limited to, various fields requiring wireless communication / connection between devices (e.g., 5G).

[0487] In the following, more specific examples will be described with reference to the accompanying drawings. In the following drawings / descriptions, similar reference numerals may represent the same or corresponding hardware blocks, software blocks or functional blocks unless otherwise specified.

[0488] Fig.28 A communication system 1 applied to the present disclosure is shown.

[0489] Reference Fig.28, the communication system 1 applied to the present disclosure includes a wireless device, a BS, and a network. The wireless device is a device that performs communication using a radio access technology (RAT) (e.g., 5G NR (or new RAT) or LTE), also referred to as a communication / radio / 5G device. The wireless device may include (but is not limited to) a robot 100a, a vehicle 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of vehicle-to-vehicle (V2V) communication. Herein, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television (TV), a smart phone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptop computers). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, a BS and a network may be implemented as wireless devices, and a specific wireless device 200a may operate as a BS / network node for other wireless devices.

[0490] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without the intervention of the BS / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0491] Wireless communication / connection 150a, 150b and 150c may be established between wireless devices 100a to 100f / BS200 and between BS200. Herein, wireless communication / connection may be established through various RATs (e.g., 5G NR) such as UL / DL communication 150a, side link communication 150b (or D2D communication) or inter-BS communication (e.g., relay or integrated access backhaul (IAB)). Wireless signals may be sent and received between wireless devices, between wireless devices and BSs, and between BSs through wireless communication / connection 150a, 150b and 150c. For example, signals may be sent and received via various physical channels through wireless communication / connection 150a, 150b and 150c. To this end, at least a portion of various configuration information for configuring processes for sending / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation and resource mapping / demapping) and resource allocation processes may be performed based on various proposals of the present disclosure.

[0492] Fig.29 A wireless device suitable for use with the present disclosure is shown.

[0493] Reference Fig.29 , the first wireless device 100 and the second wireless device 200 may transmit wireless signals via various RATs (e.g., LTE and NR). {The first wireless device 100 and the second wireless device 200} may correspond to Fig.26 {wireless device 100x and BS 200} and / or {wireless device 100x and wireless device 100x}.

[0494] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and also include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the description, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals through the transceiver 106. The processor 102 may receive a wireless signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102, and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including instructions for executing all or part of the processing controlled by the processor 102 or for executing the description, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. The processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive wireless signals through one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, the wireless device may be a communication modem / circuit / chip.

[0495] Specifically, now, instructions and / or operations controlled by the processor 102 of the first wireless device 100 and stored in the memory 104 of the first wireless device 100 according to an embodiment of the present disclosure will be described.

[0496] Although the following operations will be described based on the control operations of the processor 102 in terms of the processor 102, software codes for performing such operations may be stored in the memory 104. For example, in the present disclosure, at least one memory 104 may be a computer-readable storage medium and may store instructions or programs. The instructions or programs, when executed, may cause at least one processor operatively connected to at least one memory to perform operations related to the following operations according to an embodiment or implementation of the present disclosure.

[0497] Specifically, the processor 102 may control the transceiver 106 to receive information related to LBT from the BS. The information related to LBT and a detailed method of receiving the information may be based on at least one of [Proposed Method #1], [Proposed Method #3], or [Proposed Method #5].

[0498] The processor 102 may perform LBT for transmitting a UL signal based on the received information. If it is determined through LBT that the channel is idle, the processor 102 may control the transceiver 106 to transmit the UL signal. A detailed method in which the processor 102 controls the transceiver 106 to transmit the UL signal by performing LBT may be based on at least one of [Proposed Method #1], [Proposed Method #2], or [Proposed Method #4].

[0499] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and also include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the description, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a wireless signal including the third information / signals through the transceiver 206. The processor 202 may receive a wireless signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for executing all or part of the processing controlled by the processor 202 or for executing the description, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. The processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive wireless signals through one or more antennas 208. Each transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, the wireless device may be a communication modem / circuit / chip.

[0500] Specifically, now, instructions and / or operations controlled by the processor 202 of the second wireless device 200 and stored in the memory 204 of the second wireless device 200 according to an embodiment of the present disclosure will be described.

[0501] Although the following operations will be described based on the control operations of the processor 202 in terms of the processor 202, software codes for performing such operations may be stored in the memory 204. For example, in the present disclosure, at least one memory 204 may be a computer-readable storage medium and may store instructions or programs. The instructions or programs, when executed, may cause at least one processor operatively connected to at least one memory to perform operations related to the following operations according to an embodiment or implementation of the present disclosure.

[0502] Specifically, the processor 202 may control the transceiver 106 to send the LBT-related information to the UE. The LBT-related information and the detailed method of receiving the information may be based on at least one of [Proposed Method #1], [Proposed Method #3], or [Proposed Method #5].

[0503] The processor 202 may control the transceiver 206 to receive a UL signal from the UE. The received UL signal may be transmitted based on at least one of [Proposed Method #1], [Proposed Method #2], or [Proposed Method #4].

[0504] Now, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by (but not limited to) one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), RRC, and service data adaptation protocol (SDAP)). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document, and provide these messages, control information, data, or information to one or more transceivers 106 and 206. One or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document, and provide the generated signal to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document.

[0505] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs) or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document may be included in one or more processors 102 and 202 or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document may be implemented in the form of codes, instructions and / or instruction sets using firmware or software.

[0506] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions and / or commands. One or more memories 104 and 204 may be configured to include read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drive, registers, cache memory, computer-readable storage media and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0507] One or more transceivers 106 and 206 may send user data, control information and / or wireless signals / channels mentioned in the method and / or operation flow chart of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information and / or wireless signals / channels mentioned in the description, function, process, proposal, method and / or operation flow chart disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and send and receive wireless signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may send user data, control information or wireless signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information or wireless signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to send and receive user data, control information and / or radio signals / channels mentioned in the description, functions, processes, proposals, methods and / or operation flow charts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert the received wireless signals / channels from RF band signals to baseband signals so as to process the received user data, control information and wireless signals / channels using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert the user data, control information and wireless signals / channels processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more of the transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0508] Fig.30 A vehicle or an autonomous vehicle applied to the present disclosure is shown. The vehicle or the autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0509] Reference Fig.30, the vehicle or autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a drive unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as a part of the communication unit 110. The communication unit 110 may send and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 may perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 may include an ECU. The drive unit 140a may enable the vehicle or autonomous driving vehicle 100 to travel on a road. The drive unit 140a may include an engine, a motor, a power system, wheels, brakes, a steering device, etc. The power supply unit 140b may supply power to the vehicle or autonomous driving vehicle 100, and include a wired / wireless charging circuit, a battery, etc. The sensor unit 140c may acquire information about vehicle status, surrounding environment information, user information, etc. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, a lighting sensor, a pedal position sensor, etc. The autonomous driving unit 140d may implement a technology for maintaining a lane in which the vehicle is traveling, a technology for automatically adjusting a speed (e.g., adaptive cruise control), a technology for autonomously traveling along a determined path, a technology for traveling by automatically setting a route if a destination is set, and the like.

[0510] For example, the communication unit 110 may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan from the obtained data. The control unit 120 may control the drive unit 140a so that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 may aperiodically / periodically obtain the latest traffic information data from the external server and obtain surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain information about the vehicle state and / or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and driving plan based on the newly obtained data / information. The communication unit 110 may transmit information about the vehicle position, autonomous driving route, and / or driving plan to an external server. The external server may predict traffic information data using AI technology based on information collected from the vehicle or autonomous driving vehicle, and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0511] The embodiments of the present disclosure described below are combinations of elements and features of the present disclosure in a prescribed form. Unless otherwise specified, elements or features may be considered as selective. Each element or feature may be implemented without being combined with other elements or features. In addition, the embodiments of the present disclosure may be constructed by combining parts of elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some constructions of any one embodiment may be included in another embodiment or replaced by the corresponding construction of another embodiment. It is obvious to those skilled in the art that the claims that are not clearly referenced to each other in the attached claims may be presented as embodiments of the present disclosure in combination, or may be included as new claims by subsequent amendments after submitting an application.

[0512] In the present disclosure, in some cases, a specific operation described as being performed by a BS may be performed by an upper node of the BS. That is, it is apparent that in a network including a plurality of network nodes including a BS, various operations performed for communicating with an MS may be performed by the BS or a network node other than the BS. The term "BS" may be replaced with the term "fixed station", "Node B", "enhanced Node B (eNode B or eNB)", "access point", etc.

[0513] Those skilled in the art will appreciate that the present disclosure may be implemented in other specific ways than those described herein without departing from the spirit and essential characteristics of the present disclosure. Therefore, the above-described embodiments are to be interpreted in all respects as being illustrative and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents (rather than the above description), and all changes falling within the meaning and equivalent scope of the appended claims are intended to be included therein.

[0514] Industrial Applicability

[0515] Although the above-mentioned method of performing CAP and the apparatus for the method have been described based on an example applied to a 5G NR system, the method and the apparatus are applicable to various wireless communication systems in addition to the 5G NR system.

Claims

1. A method performed by a user equipment UE, the method comprising the following steps: Receiving first information related to an uplink UL transmit beam; Determine a beam for a channel access procedure CAP based on the first information; as well as transmitting an uplink signal through the UL transmission beam based on sensing a channel as idle by performing the CAP using the beam for the CAP, Wherein, based on the UE indicating to the base station that beam correspondence does not require beam scanning, the beam used for the CAP is determined to be the same as the UL transmission beam.

2. The method according to claim 1, wherein: Based on the UE not supporting the beam correspondence without beam scanning, the beam used for the CAP is determined to cover the UL transmission beam.

3. The method according to claim 1, wherein: The beam used for the CAP is re-determined based on failing to perform the CAP M1 times, where M1 is a positive integer.

4. The method according to claim 3, wherein: The UL bandwidth part BWP is switched based on a failure M1 of performing the CAP according to the re-determined beam for the CAP.

5. A user equipment UE, the UE comprising: at least one transceiver; at least one processor; as well as at least one memory operatively connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: receiving, by the at least one transceiver, first information related to an uplink UL transmission beam, determining a beam for a channel access procedure CAP based on the first information, and transmitting, by the at least one transceiver, an uplink signal through the UL transmit beam based on success of the CAP using the beam for the CAP, Wherein, based on the UE indicating to the base station that beam correspondence does not require beam scanning, the beam used for the CAP is determined to be the same as the UL transmission beam.

6. The UE according to claim 5, wherein: The beam used for the CAP is re-determined based on failing to perform the CAP M1 times, where M1 is a positive integer.

7. The UE according to claim 6, wherein: The UL bandwidth part BWP is switched based on a failure M1 of performing the CAP according to the re-determined beam for the CAP.

8. A device, comprising: at least one processor; as well as at least one memory operatively connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: Receiving first information related to an uplink UL transmit beam; determining a beam for a channel access procedure CAP based on the first information, and transmitting an uplink signal through the UL transmission beam based on sensing a channel as idle by performing the CAP using the beam for the CAP, Wherein, based on the beam correspondence indicating to the base station that no beam scanning is required, the beam used for the CAP is determined to be the same as the UL transmission beam.

9. A computer readable medium storing instructions which, when executed by a processor, cause the processor to perform the method according to claim 1.

10. A method performed by a base station BS, the method comprising the following steps: Sending first information related to an uplink UL transmit beam to a user equipment UE; as well as receiving an uplink signal from the UE through the UL transmit beam, wherein a channel based on a channel access procedure CAP on the beam is sensed as idle, a UL signal is received, and Wherein, based on receiving information from the UE indicating beam correspondence indicating that beam scanning is not required, the beam used for the CAP is the same as the UL transmission beam.

11. A base station BS, comprising: at least one transceiver; at least one processor; as well as at least one memory operatively connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: sending first information related to an uplink UL transmission beam to a user equipment UE through the at least one transceiver, and receiving, by the at least one transceiver, an uplink signal from the UE through the UL transmit beam, wherein a channel based on a channel access procedure CAP on the beam is sensed as idle, a UL signal is received, and Wherein, based on receiving information from the UE indicating beam correspondence indicating that beam scanning is not required, the beam used for the CAP is the same as the UL transmission beam.

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