Method and apparatus for receiving a downlink signal by a terminal based on a random access channel procedure in an unlicensed frequency band

Abstract

The present disclosure discloses a method by which a terminal receives a downlink signal based on a random access channel procedure (RACH procedure) in an unlicensed frequency band. Specifically, in the method, a first physical random access channel (PRACH) preamble is transmitted through message A; a random access response (RAR) is received through message B related to contention resolution in response to message A; information about setting at least one DRX timer for discontinuous reception (DRX) operation is received; and a downlink signal is received during an on-duration based on the at least one DRX timer, wherein the first PRACH preamble is a PRACH preamble mapped to a physical uplink shared channel (PUSCH) opportunity for message A, and a window for receiving message B can start at least one symbol after the last symbol of the PUSCH opportunity.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for receiving a downlink signal by a terminal based on a random access procedure in an unlicensed frequency band, and more particularly, to a method and apparatus for receiving a downlink signal by a terminal based on a two-step random access procedure and a DRX (discontinuous reception) operation in an unlicensed frequency band. Background Art

[0002] 5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS) as a means of delivering streams ranging from hundreds of megabits per second to gigabits per second. These high speeds are needed to deliver TV at 4K and higher resolutions (6K, 8K, and beyond), as well as virtual and augmented reality. Virtual reality (VR) and augmented reality (AR) applications encompass almost all immersive sports events. Some applications may require specialized network settings. For example, for VR gaming, gaming companies may need to integrate core servers with network operators' edge network servers to minimize latency.

[0003] Automobiles are expected to become a significant new driver of 5G, with numerous use cases for mobile communications in vehicles. For example, passenger entertainment requires mobile broadband with both high capacity and high mobility. The rationale is that future users will continue to expect high-quality connectivity regardless of their location and speed. Another use case in the automotive industry is augmented reality dashboards. These identify objects in the dark and overlay information about the object's distance and movement on the object the driver is viewing through the front window. In the future, wireless modules will enable communication between vehicles, information exchange between vehicles and supporting infrastructure, and information exchange between cars and other connected devices (such as those carried by pedestrians). Safety systems can help drivers drive safely by guiding alternative courses of action, thereby helping them reduce the risk of accidents. The next step is remotely controlled or autonomous vehicles. This requires extremely reliable and fast communication between different autonomous vehicles and between vehicles and infrastructure. In the future, autonomous vehicles will perform all driving activities, allowing drivers to focus solely on traffic anomalies that the vehicle itself cannot identify. The technical requirements for autonomous vehicles require ultra-low latency and ultra-fast reliability to improve traffic safety to a level unattainable by humans.

[0004] Smart cities and smart homes (referred to as smart societies) will be embedded with high-density wireless sensor networks. Distributed networks of smart sensors will identify the conditions for cost and energy efficiency maintenance in a city or house. Similar settings can be implemented for each home. Temperature sensors, window and heating controls, burglar alarms, and appliances will all be wirelessly connected. Many of these sensors are typically low-data-rate, low-power, and low-cost. However, in certain types of installations, for example, real-time HD video may be required for surveillance.

[0005] The consumption and distribution of energy (including heat or gas) is highly decentralized, requiring automated control via distributed sensor networks. Smart grids use digital information and communication technologies to interconnect these sensors to collect and act on information. This information can include supplier and consumer behavior, enabling smart grids to improve the efficiency, reliability, affordability, and sustainability of the production and distribution of fuels (such as electricity) in an automated manner. Smart grids can also be viewed as another low-latency sensor network.

[0006] The health sector has many applications that can benefit from mobile communications. Communication systems can support telemedicine, which provides clinical care from remote locations. This can help reduce distance barriers and improve healthcare services in remote rural areas that have historically been underserved. It can also be 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.

[0007] Wireless and mobile communications are becoming increasingly important in industrial applications. Cabling is expensive to install and maintain. Therefore, the possibility of replacing cables with reconfigurable wireless links presents an attractive opportunity for many industries. However, achieving this requires wireless connections to operate with cable-like latency, reliability, and capacity, and to be simplified in management. Low latency and very low error rates are new requirements for 5G connectivity.

[0008] Logistics and cargo tracking are important use cases for mobile communications, which enable the use of location-based information systems to track inventory and packages from anywhere. Logistics and cargo tracking use cases typically require low data rates but wide range and reliable location information. Summary of the Invention

[0009] Technical issues

[0010] An object of the present disclosure is to provide a method for performing a two-step random access procedure by a terminal and receiving a downlink signal based on a discontinuous reception (DRX) operation, and an apparatus therefor.

[0011] Technical objectives to be achieved in the present disclosure are not limited to the above-mentioned technical objectives, and other technical objectives not mentioned can be clearly understood from the following description by those having ordinary skill in the art to which the present disclosure pertains.

[0012] Technical Solution

[0013] According to an embodiment of the present disclosure, a method for receiving a downlink signal by a terminal based on a random access channel (RACH) process in an unlicensed frequency band is provided, and the method may include the following steps: sending a first physical random access channel (PRACH) preamble code to a base station through message A; receiving a random access response (RAR) from the base station through a message B related to contention resolution in response to message A; receiving information of at least one DRX timer configured for discontinuous reception (DRX) operation from the base station; and receiving a downlink signal from the base station during an on duration (on duration) based on the at least one DRX timer, wherein the first PRACH preamble code may be a PRACH preamble code of a physical uplink shared channel (PUSCH) opportunity mapped to message A, and the window for receiving message B may start at least one symbol after the last symbol of the PUSCH opportunity.

[0014] Here, the first PUSCH and the first PRACH preamble code based on the PUSCH opportunity can be sent through message A.

[0015] Additionally, the RAR may be a successful RAR including information about contention resolution.

[0016] In addition, only the first PRACH preamble code can be sent through message A.

[0017] Additionally, the RAR may be a fallback RAR including uplink (UL) grant information.

[0018] Alternatively, the window may start at the first symbol of a resource associated with monitoring of message B.

[0019] In addition, the PUSCH opportunity may be a valid PUSCH opportunity associated with the RACH opportunity of the first PRACH preamble.

[0020] According to the present disclosure, a device for receiving a downlink signal based on a random access channel (RACH) process in an unlicensed band is provided, the device may include: at least one processor; and at least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions, and performing specific operations based on the execution of the instructions by the at least one processor, wherein the specific operations may include: sending a first physical random access channel (PRACH) preamble through message A; receiving a random access response (RAR) through message B related to contention resolution in response to message A; receiving information of at least one DRX timer configured for discontinuous reception (DRX) operation; and receiving a downlink signal during an on-duration based on the at least one DRX timer, wherein the first PRACH preamble may be a PRACH preamble of a physical uplink shared channel (PUSCH) opportunity mapped to message A, and a window for receiving message B may start at least one symbol after the last symbol of the PUSCH opportunity.

[0021] Here, the first PUSCH and the first PRACH preamble code based on the PUSCH opportunity can be sent through message A.

[0022] Additionally, the RAR may be a successful RAR including information about contention resolution.

[0023] In addition, only the first PRACH preamble code can be sent through message A.

[0024] Additionally, the RAR may be a fallback RAR including uplink (UL) grant information.

[0025] Alternatively, the window may start at the first symbol of a resource associated with monitoring of message B.

[0026] In addition, the PUSCH opportunity may be a valid PUSCH opportunity associated with the RACH opportunity of the first PRACH preamble.

[0027] According to the present disclosure, a terminal for receiving a downlink signal based on a random access channel (RACH) process in an unlicensed band is provided, the terminal may include: 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 storing instructions, and performing specific operations based on the execution of the instructions by the at least one processor, wherein the specific operations may include: sending a first physical random access channel (PRACH) preamble to a base station through a message A; receiving a random access response (RAR) from the base station through a message B related to contention resolution in response to the message A; receiving information about at least one DRX timer configured for discontinuous reception (DRX) operation from the base station; and receiving a downlink signal from the base station during an on-duration based on the at least one DRX timer, wherein the first PRACH preamble may be a PRACH preamble mapped to a physical uplink shared channel (PUSCH) opportunity of the message A, and a window for receiving the message B may start at least one symbol after the last symbol of the PUSCH opportunity.

[0028] Beneficial effects

[0029] According to the present disclosure, a terminal in an unlicensed band can easily perform reception of a downlink signal through a two-step random access procedure.

[0030] Effects obtainable from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood from the following description by those having ordinary skill in the art to which the present disclosure pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figures 1 to 4 Examples of various wireless devices to which the embodiments of the present disclosure are applied are shown.

[0032] Figure 5 An example of a signal processing circuit to which an embodiment of the present disclosure is applied is shown.

[0033] Figure 6 This is a diagram illustrating the control plane and user plane structures of a radio interface protocol between a terminal and E-UTRAN based on the 3GPP radio access network standard.

[0034] Figure 7 This is a diagram for explaining physical channels used in the 3GPP system and a general signal transmission method using these physical channels.

[0035] Figures 8 to 10 This is a diagram used to illustrate the physical downlink control channel (PDCCH) in the NR system.

[0036] Figure 11 This is a diagram for explaining an embodiment of a discontinuous reception (DRX) operation.

[0037] Figures 12 to 14 This is a diagram for explaining channel transmission in an unlicensed band.

[0038] Figure 15 is a diagram illustrating an example of a random access procedure.

[0039] Figure 16 This is a diagram used to illustrate the multiplexing of long physical uplink control channel (PUCCH) and short PUCCH in the NR system.

[0040] Figure 17 The ACK / NACK transmission process is illustrated.

[0041] Figures 18 to 23 This is a diagram used to explain the composition and transmission method of the SS / PBCH block.

[0042] Figures 24 to 26 This diagram illustrates the structure of radio frames and time slots used in the NR system.

[0043] Figures 27 and 28 It is a diagram for explaining a specific operation implementation example of a terminal and a base station according to an embodiment of the present disclosure.

[0044] Figure 29 This is a diagram illustrating the basic processing of 2-step RACH.

[0045] Figure 30 is a diagram illustrating an example of configuring a reception window of Msg B according to success or failure of LBT for Msg A PUSCH transmission.

[0046] Figure 31 : is a diagram illustrating an example of configuring the reception window of Msg B regardless of the success or failure of LBT for Msg A PUSCH transmission.

[0047] Figure 32 : is a diagram illustrating an example of configuring the reception window of MsgB according to a PUSCH opportunity in which LBT has succeeded among a plurality of PUSCH opportunities.

[0048] Figure 33 : is a diagram illustrating an example of configuring the reception window of Msg B according to the last PUSCH opportunity regardless of the success or failure of LBT among multiple PUSCH opportunities.

[0049] Figure 34 An example of a wireless communication environment to which embodiments of the present disclosure may be applied is shown. DETAILED DESCRIPTION

[0050] The configuration, operation, and other features of the present disclosure can be easily understood by the embodiments of the present disclosure described below with reference to the accompanying drawings. The embodiments described below are examples of applying the technical features of the present disclosure to a 3GPP system.

[0051] Although the present disclosure uses an LTE system, an LTE-A system, and an NR system to describe the embodiments of the present disclosure, these are merely examples, and the embodiments of the present disclosure may be applied to any communication system falling within the above definitions.

[0052] In addition, in the present disclosure, the name of the base station may be used as a general term including remote radio head (RRH), eNB, transmission point (TP), reception point (RP), relay, etc.

[0053] 3GPP-based communication standards define downlink physical channels corresponding to resource elements that carry information originating from higher layers, as well as downlink physical signals corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. For example, the Physical Downlink Shared Channel (PDSCH), Physical Broadcast Channel (PBCH), Physical Multicast Channel (PMCH), Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), and Physical Hybrid ARQ Indicator Channel (PHICH) are defined as downlink physical channels, and reference signals and synchronization signals are defined as downlink physical signals. Reference signals (RS), also known as pilots, are signals with predefined waveforms known to both the gNB and the UE. For example, cell-specific RS, UE-specific RS (UE-RS), positioning RS (PRS), and channel state information RS (CSI-RS) are defined as downlink reference signals. 3GPP LTE / LTE-A standards define uplink physical channels corresponding to resource elements that carry information originating from higher layers, as well as uplink physical signals corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. For example, the physical uplink shared channel (PUSCH), the physical uplink control channel (PUCCH), and the physical random access channel (PRACH) are defined as uplink physical channels, and a demodulation reference signal (DMRS) for uplink control / data signals and a sounding reference signal (SRS) for uplink channel measurement are defined.

[0054] In the present disclosure, PDCCH (Physical Downlink Control Channel) / PCFICH (Physical Control Format Indicator Channel) / PHICH (Physical Hybrid Automatic Repeat Request Indicator Channel) / PDSCH (Physical Downlink Shared Channel) refers to a set of time-frequency resources or a set of resource elements that carry DCI (Downlink Control Information) / CFI (Control Format Indicator) / downlink ACK / NACK (Acknowledgement / Negative ACK) / downlink data, respectively. In addition, PUCCH (Physical Uplink Control Channel) / Physical Uplink Shared Channel (PUSCH) / Physical Random Access Channel (PRACH) refers to a set of time-frequency resources or a set of resource elements that carry uplink control information (UCI) / uplink data / random access signals, respectively. Specifically, the time-frequency resources or resource elements (REs) allocated to or belonging to the PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH are referred to as PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH REs or PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH resources, respectively. Hereinafter, the expression "a user equipment transmits PUCCH / PUSCH / PRACH" is used in the same sense as transmitting uplink control information / uplink data / random access signals on or through the PUSCH / PUCCH / PRACH. Furthermore, the expression "a gNB transmits PDCCH / PCFICH / PHICH / PDSCH" is used in the same sense as transmitting downlink data / control information on or through the PDCCH / PCFICH / PHICH / PDSCH.

[0055] In the following, the OFDM symbol / subcarrier / RE to which CRS / DMRS / CSI-RS / SRS / UE-RS is assigned or configured is referred to as CRS / DMRS / CSI-RS / SRS / UE-RS symbol / carrier / subcarrier / RE. For example, the OFDM symbol to which the tracking RS (TRS) is assigned or configured is referred to as the TRS symbol, the subcarrier to which the TRS is assigned or configured is referred to as the TRS subcarrier, and the RE to which the TRS is assigned or configured is referred to as the TRS RE. In addition, the subframe configured to be sent by TRS is referred to as the TRS subframe. In addition, the subframe in which the broadcast signal is sent is referred to as the broadcast subframe or the PBCH subframe, and the subframe in which the synchronization signal (e.g., PSS and / or SSS) is sent is referred to as the synchronization signal subframe or the PSS / SSS subframe. The OFDM symbol / subcarrier / RE to which the PSS / SSS is assigned or configured is referred to as the PSS / SSS symbol / subcarrier / RE, respectively.

[0056] In the present disclosure, CRS port, UE-RS port, CSI-RS port and TRS port respectively mean an antenna port configured to send CRS, an antenna port configured to send UE-RS, an antenna port configured to send CSI-RS and an antenna port configured to send TRS. Antenna ports configured to send CRS can be distinguished from each other according to the position of RE occupied by CRS based on the CRS port; antenna ports configured to send UE-RS can be distinguished from each other according to the position of RE occupied by UE-RS based on the UE-RS port; antenna ports configured to send CSI-RS can be distinguished from each other according to the position of RE occupied by CSI-RS based on the CSI-RS port. Therefore, the term CRS / UE-RS / CSI-RS / TRS port is also used as a term to mean the pattern of RE occupied by CRS / UE-RS / CSI-RS / TRS within a specific resource area.

[0057] Figure 1 A wireless device to which the present disclosure is applied is exemplified.

[0058] Reference Figure 1 , the first wireless device 100 and the second wireless device 200 can transmit / receive wireless signals through various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device 100, the second wireless device 200} can be connected to Figure 30 The wireless device 100x and the base station 200 correspond to each other.

[0059] The first wireless device 100 includes one or more processors 102 and one or more memories 104, and may also include one or more transceivers 106 and / or one or more antennas 108. The processor 102 controls the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed herein. For example, the processor 102 may process 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. In addition, the processor 102 may receive a wireless signal including second information / signals through the transceiver 106, and then store information obtained from the signal processing of 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 code including instructions for performing some or all of the processing controlled by the processor 102, or for performing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this document. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver 106 may be connected to the processor 102 and may send and / or receive wireless signals via one or more antennas 108. The 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, a wireless device may refer to a communication modem / circuit / chip.

[0060] In detail, instructions and / or operations controlled by the processor 102 of the first wireless device 100 and stored in the memory 104 according to an embodiment of the present disclosure will be described.

[0061] The following operations are described based on control operations of the processor 102 from the perspective of the processor 102 , but may be stored in the memory 104 as software codes for executing the operations.

[0062] The processor 102 may control the transceiver 106 to transmit a first physical random access channel (PRACH) preamble using message A. Furthermore, the processor 102 may control the transceiver 106 to receive a random access response (RAR) using message B related to contention resolution. In this case, the specific method by which the processor 102 controls the transceiver 106 to transmit message A and to receive message B may be based on the following example.

[0063] Specifically, instructions and / or operations controlled by the processor 202 of the second wireless device 200 and stored in the memory 204 according to an embodiment of the present disclosure will be described.

[0064] The following operations are described based on the control operations of the processor 202 from the perspective of the processor 202 , but software codes for executing these operations may be stored in the memory 204 .

[0065] The processor 202 may control the transceiver 206 to receive a first physical random access channel (PRACH) preamble using message A. Furthermore, the processor 202 may control the transceiver 206 to transmit a random access response (RAR) using message B related to contention resolution. In this case, the specific method by which the processor 202 controls the transceiver 206 to receive message A and to transmit message B may be based on the following example.

[0066] In the following, the hardware components of the wireless devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or flowcharts disclosed herein. The one or more processors 102 and 202 generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed herein and provide them to the one or more transceivers 106 and 206. The one or more processors 102, 202 may receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and may obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flow charts disclosed herein.

[0067] One or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or flowcharts of the operations disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. The firmware or software configured to perform the descriptions, functions, processes, suggestions, methods, and / or flowcharts disclosed herein may be included in one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions of operations, functions, processes, suggestions, methods, and / or flow diagrams disclosed herein may be implemented using firmware or software in the form of codes, instructions, and / or instruction sets.

[0068] One or more memories 104, 204 can be coupled to one or more processors 102, 202 and can store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104, 204 can be comprised of ROM, RAM, EPROM, flash memory, a hard drive, registers, cache memory, a computer-readable storage medium, and / or a combination thereof. One or more memories 104, 204 can be located internally and / or externally to one or more processors 102, 202. In addition, one or more memories 104, 204 can be coupled to one or more processors 102, 202 via various technologies, such as wired or wireless connections.

[0069] One or more transceivers 106, 206 can transmit user data, control information, radio signals / channels, etc., as described in the methods and / or operational flowcharts herein, to one or more other devices. The one or more transceivers 106, 206 can receive user data, control information, radio signals / channels, etc., as described, functions, processes, suggestions, methods, and / or flowcharts disclosed herein, from one or more other devices. For example, one or more transceivers 106, 206 can be coupled to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 can be connected to one or more antennas 108, 208 and can be configured to transmit and receive user data, control information, radio signals / channels, etc. mentioned in the description, function, process, proposal, method and / or operation flow chart through the one or more antennas 108, 208. In this document, one or more antennas can be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 convert the received radio signals / channels, etc. from RF band signals to baseband signals so as to process the received user data, control information, radio signals / channels, etc. using the one or more processors 102, 202. The one or more transceivers 106 and 206 can convert the user data, control information, radio signals / channels, etc. processed using the one or more processors 102 and 202 from baseband signals to RF band signals. To this end, the one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0070] Figure 2 Another example of a wireless device applied to the present disclosure is shown. The wireless device can be implemented in various forms according to use cases / services (see Figure 34 ).

[0071] Reference Figure 2 , wireless devices 100 and 200 can communicate with Figure 1The wireless devices 100 and 200 correspond to each other and may be composed of various elements, components, units / components and / or modules. For example, the wireless devices 100 and 200 may include: a communication unit 110, a control unit 120, a memory unit 130 and an additional element 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Figure 1 The one or more processors 102, 202 and / or the one or more memories 104, 204 of the present invention may include: Figure 1 The one or more transceivers 106, 206 and / or one or more antennas 108, 208 of the wireless device are connected to the communication unit 110, the memory unit 130, and the additional element 140, and controls the general operation of the wireless device. For example, the controller 120 can control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit 130. In addition, the control unit 120 can transmit the information stored in the memory unit 130 to the outside (e.g., another communication device) via the wireless interface / wired interface through the communication unit 110, or can store information received from the outside (e.g., another communication device) via the wireless interface / wired interface through the communication unit 110 in the memory unit 130. Therefore, the specific operation process of the control unit 120 according to the present disclosure and the program / code / instruction / information stored in the memory unit 130 may correspond to Figure 2 The operation of at least one of the processors 102 and 202 and the operation of at least one of the memories 104 and 204 are performed.

[0072] The additional element 140 may be configured differently depending on the type of wireless device. For example, the additional element 140 may include at least one of a power supply unit / battery, an input / output unit (I / O unit), a drive unit, and a computing unit. Although not limited thereto, the wireless device may include a robot ( Figure 34 100a), vehicle ( Figure 34 100b-1, 100b-2), XR device ( Figure 34 100c in), mobile devices ( Figure 34 100d) and household appliances ( Figure 34 100e in), IoT devices ( Figure 34 100f in), digital broadcast terminals, holographic devices, public safety devices, MTC devices, medical devices, financial technology (fintech) devices (or financial devices), security devices, climate / environmental devices, which can be AI servers / devices ( Figure 34 400 in), base station ( Figure 34Depending on the use case / service, the wireless device may be mobile or used in a fixed location.

[0073] exist Figure 2 In the wireless devices 100 and 200, the various elements, components, units / parts, and / or modules may all be interconnected via wired interfaces, or at least some of them may be wirelessly connected via the communication unit 110. For example, in the wireless devices 100 and 200, the control unit 120 and the communication unit 110 are connected via wiring, and the control unit 120 and the first unit (e.g., 130, 140) may be wirelessly connected to the communication unit 110 via the communication unit 110. In addition, each element, component, unit / part, and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the controller 120 may be configured with one or more processor groups. For example, the control unit 120 may be configured as a group of communication control processors, application processors, electronic control units (ECUs), graphics processing processors, memory control processors, etc. As another example, the memory unit 130 may include random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), flash memory, volatile memory, non-volatile memory, and / or combinations thereof.

[0074] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. Figure 2 Implementation example.

[0075] Figure 3 The present disclosure is illustrated as a portable device. Portable devices may include smartphones, smart tablets, wearable devices (e.g., smart watches, smart glasses), and portable computers (e.g., laptop computers). A mobile device may be referred to as a mobile station (MS), user terminal (UT), mobile subscriber station (MSS), subscriber station (SS), advanced mobile station (AMS), or wireless terminal (WT).

[0076] Reference Figure 3 , the portable device 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a memory unit 130, a power supply unit 140a, an interface unit 140b, and an input / output unit 140c. The antenna unit 108 may be configured as a part of the communication unit 110. The blocks 110 to 130 / 140a to 140c are respectively Figure 2 Corresponding to blocks 110 to 130 / 140.

[0077] The communication unit 110 can send and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The controller 120 can perform various operations by controlling the components of the portable device 100. The controller 120 may include an application processor (AP). The memory unit 130 can store data / parameters / programs / codes / commands required to drive the portable device 100. In addition, the memory unit 130 can store input / output data / information. The power supply unit 140a supplies power to the portable device 100 and may include wired / wireless charging circuits, a battery, etc. The interface unit 140b can support connections between the portable device 100 and other external devices. The interface unit 140b may include various ports for connecting to external devices (e.g., audio input / output ports and video input / output ports). The input / output unit 140c can receive or output image information / signals, audio information / signals, data, and / or information input from the user. The input / output unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and / or a haptic module.

[0078] For example, in the case of data communication, the input / output unit 140c obtains information / signals (e.g., touch, text, voice, image, video) input from the user and can store the obtained information / signals in the memory unit (130). The communication unit 110 can convert the information / signals stored in the memory into wireless signals and directly transmit the converted wireless signals to another wireless device or base station. In addition, after receiving a radio signal from another wireless device or base station, the communication unit 110 can restore the received radio signal to the original information / signal. After the restored information / signal is stored in the memory unit 130, it can be output in various forms (e.g., text, voice, image, video, tactile) through the input / output unit 140c.

[0079] Figure 4 The vehicle or autonomous driving vehicle to which the present disclosure is applied is exemplified. The vehicle or autonomous driving vehicle can be implemented as a mobile robot, a transportation vehicle, a train, an aircraft (AV), a ship, etc.

[0080] Reference Figure 4 , the vehicle or autonomous 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 drive unit 140d. The antenna unit 108 may be configured as a part of the communication unit 110. The blocks 110 / 130 / 140a to 140d are respectively Figure 2 Corresponding to blocks 110 / 130 / 140.

[0081] The communication unit 110 can send and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations, etc.), servers, etc. The controller 120 can control the elements of the vehicle or autonomous driving vehicle 100 to perform various operations. The controller 120 may include an electronic control unit (ECU). The drive unit 140a can enable the vehicle or autonomous driving vehicle 100 to travel on the ground. The drive unit 140a may include: an engine, an electric motor, a powertrain, wheels, brakes, a steering device, etc. The power supply unit 140b supplies power to the vehicle or autonomous driving vehicle 100, and may include a wired / wireless charging circuit, a battery, etc. The sensor unit 140c can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit 140 c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a tilt sensor, a weight sensor, a heading sensor, a location module, a vehicle forward / reverse movement sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, etc. The autonomous driving unit 140 d may implement a technology for maintaining a driving lane, a technology for automatically adjusting a speed (e.g., adaptive cruise control), a technology for autonomous driving along a predetermined route, and a technology for automatically setting a route when a destination is set.

[0082] For example, the communication unit 110 can receive map data, traffic information data, and the like from an external server. The autonomous driving unit 140d can generate an autonomous driving route and driving plan based on the acquired data. The controller 120 can control the drive unit 140a to move the vehicle or autonomous driving vehicle 100 along the autonomous driving path (e.g., speed / direction adjustment) according to the driving plan. During autonomous driving, the communication unit 110 can aperiodically or periodically obtain the latest traffic information data from the external server and can obtain surrounding traffic information data from surrounding vehicles. In addition, during autonomous driving, the sensor unit 140c can obtain vehicle status and surrounding environment information. The autonomous driving unit 140d can update the autonomous driving route and driving plan based on the latest acquired data / information. The communication unit 110 can send information about the vehicle's location, autonomous driving route, driving plan, and the like to the external server. The external server can use AI technology, etc., based on information collected from the vehicle or autonomous driving vehicle to predict traffic information data in advance and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0083] Figure 5 A signal processing circuit for transmitting a signal is illustrated.

[0084] Reference Figure 5, the signal processing circuit 1000 may include a scrambler 1010, a modulator 1020, a layer mapper 1030, a precoder 1040, a resource mapper 1050, and a signal generator 1060. Although not limited, Figure 5 The operations / functions can be performed by Figure 1 The processors 102 and 202 and / or the transceivers 106 and 206 are executed. Figure 5 The hardware components can be Figure 1 For example, blocks 1010 to 1060 may be implemented in the processor 102, 202 and / or the transceiver 106, 206 of Figure 1 In addition, blocks 1010 to 1050 may be implemented in processors 102 and 202 of Figure 1 1 and 202, and block 1060 may be implemented in Figure 1 is implemented in the transceivers 106 and 206.

[0085] Codewords can be passed Figure 5 The signal processing circuit 1000 is converted into a wireless signal. Here, a codeword is a coded bit sequence of an information block. An information block may include a transport block (e.g., UL-SCH transport block, DL-SCH transport block). Radio signals can be transmitted via various physical channels (e.g., PUSCH, PDSCH).

[0086] Specifically, the codeword can be converted into a scrambled bit sequence by the scrambler 1010. A scrambling sequence for scrambling is generated based on an initialization value, and the initialization value may include ID information of the wireless device, etc. The scrambled bit sequence can be modulated into a modulation symbol sequence by the modulator 1020. Modulation methods may include: pi / 2-binary phase shift keying (pi / 2-BPSK), m-phase shift keying (m-PSK), m-quadrature amplitude modulation (m-QAM), etc. The complex modulation symbol sequence can be mapped to one or more transmission layers by the layer mapper 1030. The modulation symbol (precoding) of each transmission layer can be mapped to the corresponding antenna port by the precoder 1040. The output z of the precoder 1040 can be obtained by multiplying the output y of the layer mapper 1030 by the N*M precoding matrix W. Here, N is the number of antenna ports and M is the number of transmission layers. Here, the precoder 1040 can perform precoding after performing transform precoding (e.g., DFT transform) on the complex modulation symbols. In addition, the precoder 1040 may perform precoding without performing transform precoding.

[0087] The resource mapper 1050 may map the modulation symbols for each antenna port to time-frequency resources. The time-frequency resources may include multiple symbols in the time domain (e.g., CP-OFDMA symbols, DFT-s-OFDMA symbols) and multiple subcarriers in the frequency domain. The signal generator 1060 generates a radio signal from the mapped modulation symbols and may transmit the generated radio signal to another device via each antenna. To this end, the signal generator 1060 may include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), a frequency uplink converter, and the like.

[0088] Can be used with Figure 5 The signal processing processes 1010 to 1060 of the wireless device are oppositely configured to process the signal received in the wireless device. For example, the wireless device (eg, Figure 1 100 and 200 in ) can receive a wireless signal from the outside through an antenna port / transceiver. The received radio signal can be converted into a baseband signal by a signal restorer. To this end, the signal restorer may include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Thereafter, the baseband signal can be restored to a codeword through resource demapper processing, post-coding processing, demodulation processing, and descrambling processing. The codeword can be restored to the original information block by decoding. Therefore, the signal processing circuit (not shown) for the received signal may include a signal restorer, a resource demapper, a post-coder, a demodulator, a descrambler, and a decoder.

[0089] Figure 6 This diagram illustrates the control plane and user plane structures of the radio interface protocol between a terminal and E-UTRAN based on the 3GPP radio access network standard. The control plane is a path through which control messages used by user equipment (UE) and the network to manage calls are transmitted. The user plane is a path through which data generated in the application layer (e.g., voice data or internet packet data) is transmitted.

[0090] The physical layer, as the first layer, provides information transmission services to upper layers using physical channels. The physical layer is connected to the upper-layer medium access control layer via a transport channel. Data moves between the medium access control layer and the physical layer via the transport channel. Data moves between the physical layer on the transmitting side and the physical layer on the receiving side via the physical channel. The physical channel uses time and frequency as radio resources. Specifically, the physical channel is modulated using an orthogonal frequency division multiple access (OFDMA) scheme in the downlink and a single-carrier frequency division multiple access (SC-FDMA) scheme in the uplink.

[0091] The Medium Access Control (MAC) layer of the second layer provides services to the upper layer (Radio Link Control (RLC) layer) via logical channels. The RLC layer of the second layer supports reliable data transmission. The functions of the RLC layer can be implemented as a functional block within the MAC. The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function that reduces unnecessary control information to facilitate efficient transmission of IP packets such as IPv4 or IPv6 over a narrow-bandwidth air interface.

[0092] The Radio Resource Control (RRC) layer at the bottom of the third layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transport channels, and physical channels related to the configuration, reconfiguration, and release of radio bearers. Radio bearers refer to services provided by the second layer for data transmission between the UE and the network. To this end, the RRC layer of the UE and the RRC layer of the network exchange RRC messages with each other. If there is an RRC connection between the UE and the RRC layer of the network (RRC connected), the UE is in an RRC connected state (connected mode), otherwise the UE is in an RRC idle state (idle mode). The NAS (Non-Access Stratum) layer above the RRC layer performs functions such as session management and mobility management.

[0093] The downlink transport channels used to send data from the network to the UE include the BCH (broadcast channel) for transmitting system information, the PCH (paging channel) for transmitting paging messages, and the downlink SCH (shared channel) for transmitting user services or control messages. In the case of downlink multicast or broadcast service services or control messages, they can be transmitted through the downlink SCH, or can be transmitted through a separate downlink multicast channel (MCH). In addition, as uplink transport channels for transmitting data from the UE to the network, there is a random access channel (RACH) for transmitting initial control messages and an uplink shared channel (SCH) for sending user services or control messages. The logical channels located above the transport channel and mapped to the transport channel include the broadcast control channel (BCCH), the paging control channel (PCCH), the common control channel (CCCH), the multicast control channel (MCCH), and the multicast traffic channel (MTCH).

[0094] Figure 7 This is a diagram for explaining physical channels used in the 3GPP system and a general signal transmission method using these physical channels.

[0095] When the UE is powered on or enters a new cell, it performs an initial cell search operation (such as synchronization with a base station) (S701). To this end, the UE may receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station, synchronize with the base station, and obtain information such as a cell ID. Thereafter, the UE may receive a physical broadcast channel (PBCH) from the base station to obtain intra-cell broadcast information. In addition, the UE may receive a downlink reference signal (DL RS) during the initial cell search step to check the downlink channel status.

[0096] The UE that has completed the initial cell search may receive a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried on the PDCCH and obtain more specific system information ( S702 ).

[0097] In addition, when there are no radio resources for initial access to the base station or for signal transmission, the UE can perform a random access procedure (RACH procedure) with respect to the base station (S703 to S706). To this end, the UE can transmit a specific sequence as a preamble through the physical random access channel (PRACH) (S703 and S705) and receive a response message (random access response (RAR) message) in response to the preamble through the PDCCH and the corresponding PDSCH. In the case of a contention-based RACH, a contention resolution procedure (S706) can be additionally performed.

[0098] After performing the above-described process, the UE may perform PDCCH / PDSCH reception (S707) and physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) transmission (S708) as a general uplink / downlink signal transmission process. Specifically, the UE may receive downlink control information (DCI) via the PDCCH. Here, the DCI includes control information such as resource allocation information for the UE, and may be in different formats depending on the purpose of use.

[0099] In addition, the control information transmitted by the UE to the base station through the uplink or received by the UE from the base station may include downlink / uplink ACK / NACK signals, CQI (channel quality indicator), PMI (precoding matrix index), RI (rank indicator), etc. The UE can transmit the above control information such as CQI / PMI / RI through the PUSCH and / or PUCCH.

[0100] In addition, the NR system is considering using a method of using a high ultra-high frequency band (i.e., a millimeter wave band of 6 GHz or higher) to transmit data to a large number of users using a wide frequency band while maintaining a high data rate. In 3GPP, this is called NR, and in this disclosure, it is referred to as an NR system.

[0101] NR supports multiple OFDM (Orthogonal Frequency Division Multiplexing) numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15kHz, it supports wide areas in traditional cellular bands, when the SCS is 30kHz / 60kHz, it supports dense cities, lower latency, and wider carrier bandwidth, and when the SCS is 60kHz or higher, it supports bandwidth greater than 24.25kHz to overcome phase noise.

[0102] The NR band is defined as two types of frequency ranges (FR1, FR2). FR1 is a range below 6 GHz, and FR2 is a range above 6 GHz, which may mean millimeter waves (mmW).

[0103] Table 1 below shows the definition of NR frequency bands.

[0104] [Table 1]

[0105] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15kHz, 30kHz, 60kHz FR2 24250MHz-52600MHz 60kHz, 120kHz, 240kHz

[0106] Downlink channel structure

[0107] The base station transmits a relevant signal to the UE through a downlink channel to be described later, and the UE receives a relevant signal from the base station through a downlink channel to be described later.

[0108] (1) Physical Downlink Shared Channel (PDSCH)

[0109] The PDSCH carries downlink data (e.g., DL shared channel transport block, DL-SCH TB) and applies modulation methods such as QPSK (quadrature phase shift keying), 16QAM (quadrature amplitude modulation), 64QAM, 256QAM, etc. A codeword is generated by encoding the TB. The PDSCH can carry up to two codewords. Scrambling and modulation mapping are performed for each codeword, and the modulation symbols generated from each codeword are mapped to one or more layers (layer mapping). Each layer is mapped to a resource together with a demodulation reference signal (DMRS), generated as an OFDM symbol signal, and transmitted through the corresponding antenna port.

[0110] (2) Physical Downlink Control Channel (PDCCH)

[0111] The PDCCH carries downlink control information (DCI) and uses the QPSK modulation method. A PDCCH consists of 1, 2, 4, 8, or 16 control channel elements (CCEs) depending on the aggregation level (AL). A CCE consists of six resource element groups (REGs). A REG is defined as one OFDM symbol and one (P)RB.

[0112] Figure 8 A REG structure is shown in Figure 8 In [ ], D represents the resource element (RE) to which DCI is mapped, and R represents the RE to which DMRS is mapped. DMRS is mapped to RE#1, RE#5, and RE#9 along the frequency domain within one symbol.

[0113] The PDCCH is transmitted through a control resource set (CORESET). A CORESET is defined as a set of REGs with a given parameter set (e.g., SCS, CP length, etc.). Multiple CORESETs for a UE can overlap in the time / frequency domain. The CORESET can be configured through system information (e.g., MIB) or UE-specific higher-layer (e.g., radio resource control RRC layer) signaling. Specifically, the number of RBs and the number of symbols (up to 3) that constitute the CORESET can be configured by higher-layer signaling.

[0114] The precoder granularity of each CORESET in the frequency domain is configured by higher layer signaling to be one of the following:

[0115] -sameAsREG-bundle: same as REG bundle size in frequency domain

[0116] -allContiguousRBs: equal to the number of contiguous RBs in the frequency domain within CORESET

[0117] The REGs in the CORESET are numbered based on a time-first mapping scheme, that is, starting from the first OFDM symbol in the lowest-numbered resource block in the CORESET, and numbering the REGs sequentially from 0.

[0118] The mapping type from CCE to REG is configured as one of a non-interleaved CCE-REG mapping type or an interleaved CCE-REG mapping type. Figure 9 (a) illustrates a non-interleaved CCE-REG mapping type, and Figure 9 (b) illustrates an interleaved CCE-REG mapping type.

[0119] - Non-interleaved CCE-REG mapping type (or localized mapping type): 6 REGs for a given CCE constitute one REG bundle, and all REGs for a given CCE are continuous. One REG bundle corresponds to one CCE

[0120] - Interleaved CCE-REG mapping type (or distributed mapping type): 2, 3, or 6 REGs for a given CCE constitute a REG bundle, and the REG bundle is interleaved within the CORESET. Within a CORESET consisting of 1 OFDM symbol or 2 OFDM symbols, the REG bundle consists of 2 or 6 REGs, and within a CORESET consisting of 3 OFDM symbols, the REG bundle consists of 3 or 6 REGs. The REG bundle size is configured per CORESET.

[0121] Figure 10 The block interleaver is illustrated. The number of rows (A) of the (block) interleaver used for the above interleaving operation is configured to be one of 2, 3, or 6. When the number of interleaving units for a given CORESET is P, the number of columns of the block interleaver is equal to P / A. The write operation on the block interleaver is as follows: Figure 10 The interleaving operation is performed in a row-first direction as shown, and the readout operation is performed in a column-first direction. The cyclic shift (CS) of the interleaving unit is applied based on an ID that can be configured independently of the ID that can be configured for the DMRS.

[0122] The UE obtains the DCI transmitted via the PDCCH by performing decoding (referred to as blind decoding) on ​​the PDCCH candidate set. The PDCCH candidate set decoded by the UE is defined as a PDCCH search space set. The search space set can be a common search space or a UE-specific search space. The UE can acquire DCI by monitoring PDCCH candidates in one or more search space sets configured by the MIB or higher layer signaling. Each CORESET configuration is associated with one or more search space sets, and each search space set is associated with one CORESET configuration. A search space set is determined based on the following parameters.

[0123] -controlResourceSetId: Indicates the control resource set associated with the search space set

[0124] -monitoringSlotPeriodicityAndOffset: Indicates the PDCCH monitoring periodicity duration (in time slots) and the PDCCH monitoring duration offset (in time slots)

[0125] - monitoringSymbolsWithinSlot: indicates the PDCCH monitoring pattern within the slot used for PDCCH monitoring (e.g., indicating the first symbol of the control resource set)

[0126] -nrofCandidates: indicates the number of PDCCH candidates per AL = {1, 2, 4, 8, 16} (one of 0, 1, 2, 3, 4, 5, 6, 8)

[0127] Table 2 illustrates the characteristics of each search space type.

[0128] [Table 2]

[0129]

[0130] Table 3 illustrates DCI formats transmitted through the PDCCH.

[0131] [Table 3]

[0132]

[0133] 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) (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 (or CBG-level) PDSCH. DCI format 2_0 can be used to convey dynamic time slot format information (e.g., dynamic SFI) to the UE, and DCI format 2_1 can be used to convey downlink preemption information to the UE. DCI format 2_0 and / or DCI format 2_1 can be delivered to the UEs in the group via a group-common PDCCH, which is a PDCCH delivered to UEs defined as a group.

[0134] Discontinuous Reception (DRX) Operation

[0135] The UE may perform DRX operation while executing the procedures and / or methods described / proposed above. A UE configured with DRX can reduce power consumption by discontinuously receiving DL signals. DRX can be performed in the RRC (Radio Resource Control)_IDLE state, the RRC_INACTIVE state, and the RRC_CONNECTED state. In the RRC_IDLE state and the RRC_INACTIVE state, DRX is used to discontinuously receive paging signals. Hereinafter, DRX performed in the RRC_CONNECTED state (RRC_CONNECTED DRX) will be described.

[0136] Figure 11 This is a diagram for explaining an embodiment of a discontinuous reception (DRX) operation.

[0137] Reference Figure 11 , the DRX cycle consists of the on-duration and opportunity of DRX. The DRX cycle defines the time interval of the periodically repeated on-duration. The on-duration indicates the period during which the UE monitors to receive the PDCCH. When DRX is configured, the UE performs PDCCH monitoring during the on-duration. If the PDCCH is successfully detected during the PDCCH monitoring, the UE operates the inactivity timer and maintains the awake state. On the other hand, if the PDCCH is not successfully detected during the PDCCH monitoring, the UE enters the sleep state after the on-duration ends. Therefore, when DRX is configured, when performing the process and / or method described / proposed above, PDCCH monitoring / reception can be performed discontinuously in the time domain. For example, when DRX is configured, in the present disclosure, PDCCH reception opportunities (e.g., time slots with PDCCH search space) can be configured discontinuously according to the DRX configuration. On the other hand, when DRX is not configured, when performing the process and / or method described / proposed above, PDCCH monitoring / reception can be performed continuously in the time domain. For example, when DRX is not configured, the PDCCH reception opportunities (eg, time slots with PDCCH search spaces) of the present disclosure may be configured continuously. In addition, regardless of whether DRX is configured, PDCCH monitoring may be limited to time intervals configured as measurement gaps.

[0138] Table 4 shows the processing of UE (RRC_CONNECTED state) related to DRX. Referring to Table 4, DRX configuration information is received through higher layer (e.g., RRC) signaling, and whether DRX is turned on / off is controlled by the DRX command of the MAC layer. If DRX is configured, Figure 11 As illustrated, the UE may perform PDCCH monitoring discontinuously when performing the procedures and / or methods proposed / described in this disclosure.

[0139] [Table 4]

[0140]

[0141] Here, MAC-CellGroupConfig includes the configuration information required to configure the MAC (Media Access Control) parameters of the cell group. MAC-CellGroupConfig may also include configuration information related to DRX. For example, MAC-CellGroupConfig may include the following information to define DRX. -drx-OnDurationTimer value: defines the length of the start duration of the DRX cycle

[0142] -drx-InactivityTimer value: defines the length of time that the UE remains awake after detecting a PDCCH opportunity indicating a PDCCH for initial UL or DL ​​data.

[0143] -drx-HARQ-RTT-TimerDL value: defines the maximum duration from the reception of a DL initial transmission until the reception of a DL retransmission.

[0144] - Value of drx-HARQ-RTT-TimerDL: defines the length of the maximum duration from when a grant for UL initial transmission is received until a grant for UL retransmission is received.

[0145] -drx-LongCycleStartOffset: defines the duration and starting point of the DRX cycle.

[0146] -DRX-ShortCycle (optional): defines the duration of the short DRX cycle

[0147] Here, if any one of drx-OnDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is in operation, the UE performs PDCCH monitoring at every PDCCH opportunity while maintaining an awake state.

[0148] Unlicensed band / shared spectrum system

[0149] Figure 12 is a diagram illustrating an example of a wireless communication system supporting an unlicensed band to which various embodiments of the present disclosure can be applied.

[0150] In the following description, a cell operating in a licensed frequency band (hereinafter referred to as the L-band) is defined as an L-cell, and a carrier of the L-cell is defined as a (DL / UL) LCC. Furthermore, a cell operating in an unlicensed frequency band (hereinafter referred to as the U-band) is defined as a U-cell, and a carrier of the U-cell is defined as a (DL / UL) UCC. A cell's carrier / carrier frequency may refer to the cell's operating frequency (e.g., center frequency). A cell / carrier (e.g., CC) may be referred to as a cell.

[0151] like Figure 12 As shown in (a), when the UE and the base station transmit and receive signals through the LCC and UCC via carrier aggregation, the LCC may be set as a primary CC (PCC) and the UCC may be set as a secondary CC (SCC).

[0152] like Figure 12 As shown in (b), the UE and the base station can send and receive signals through one UCC or multiple LCCs and UCCs via carrier aggregation. That is, the UE and the base station can send and receive signals only through the UCC without the LCC. Hereinafter, the signal transmission / reception operations in the unlicensed band described in various embodiments of the present disclosure can be performed based on all the deployment scenarios described above (unless otherwise described).

[0153] 1. Radio frame structure for unlicensed bands

[0154] For operation in the unlicensed band, the LTE frame structure type 3 or the NR frame structure can be used. The configuration of the OFDM symbols occupied for uplink / downlink signal transmission in the frame structure for the unlicensed band can be configured by the base station. Here, the OFDM symbols can be replaced with SC-FDM (A) symbols.

[0155] For downlink signal transmission through the unlicensed band, the base station may notify the UE of the configuration of OFDM symbols used in subframe #n through signaling. In the following description, subframe may be replaced with a slot or a time unit (TU).

[0156] Specifically, in the case of a wireless communication system that supports an unlicensed frequency band, the UE can assume (or identify) the configuration of the OFDM symbols occupied in subframe #n based on a specific field in the DCI received from the base station in subframe #n-1 or subframe #n (for example, the subframe configuration for the LAA field, etc.).

[0157] Table 5 illustrates a method of indicating configuration of OFDM symbols used for transmission of downlink physical channels and / or physical signals in a current subframe and / or a next subframe through a subframe configuration of an LAA field in a wireless communication system.

[0158] [Table 5]

[0159]

[0160] For uplink signal transmission through the unlicensed frequency band, the base station may notify the UE of information about uplink transmission duration through signaling.

[0161] Specifically, in the case of an LTE system supporting an unlicensed band, the UE may obtain "UL duration" and "UL offset" information for subframe #n through the "UL duration and offset" field in the detected DCI.

[0162] Table 6 illustrates a method in which the UL Duration and Offset fields indicate a UL offset and a UL duration configuration in a wireless communication system.

[0163] [Table 6]

[0164]

[0165] 2. General channel access process

[0166] Unless otherwise described, the following definitions may be applied to terms used in the description of various embodiments of the present disclosure to be described later.

[0167] A channel may mean a carrier or a portion of a carrier consisting of a set of consecutive RBs on which a channel access procedure is performed in a shared spectrum.

[0168] The channel access procedure may be a sensing-based procedure for evaluating the availability of a channel for transmission. The basic unit of sensing may be a sensing slot of duration Ts1 = 9 us. When the base station or UE senses the channel during the sensing slot duration and determines that the detected power sensed for at least 4 us within the sensing slot duration is less than the energy detection threshold XThresh, the sensing slot duration Ts1 may be considered idle. Otherwise, the sensing slot duration Ts1 may be considered busy.

[0169] - Channel occupancy may mean transmission in a channel by a base station / UE after performing a channel access procedure corresponding to the present section.

[0170] Channel occupancy time may refer to the total time that a base station / UE and any base station / UE sharing the channel transmit on a channel after the base station / UE performs the channel access procedure described in this section. To determine the channel occupancy time, if a transmission gap is 25 µs or less, the gap duration may be counted as the channel occupancy time. The channel occupancy time may be shared for transmissions between a base station and the corresponding UE.

[0171] 3. Downlink channel access process

[0172] The base station may perform the following downlink channel access procedure (channel access procedure; CAP) for the unlicensed band for downlink signal transmission in the unlicensed band.

[0173] 3.1. Type 1 Downlink (DL) Channel Access Procedure

[0174] In this section, the channel access procedure performed by the base station is described based on the fact that the duration of the sensing slots sensed as idle before the downlink transmission is random. This section can be applied to the following transmissions:

[0175] - a transmission initiated by the base station including PDSCH / PDCCH / EPDCCH, or,

[0176] - a transmission initiated by the base station comprising a unicast PDSCH with user plane data or a unicast PDSCH with user plane data and a unicast PDCCH scheduling user plane data, or

[0177] - Transmission initiated by a base station with only a discovery burst or with a discovery burst multiplexed with non-unicast information. Here, the transmission duration may be greater than 1 ms, or the transmission may cause the discovery burst duty cycle to exceed 1 / 20.

[0178] The base station is delayed for a duration of T d The channel is sensed during the additional sensing slot duration to see if it is in an idle state, and the transmission may be sent after the counter N becomes 0 in the subsequent step 4. In this case, the counter N is adjusted by channel sensing during the additional sensing slot duration according to the following procedure:

[0179] 1) Set N = N init Here, N init is evenly distributed between 0 and CW p Then, proceed to step 4.

[0180] 2) If N>0 and the base station chooses to decrement the counter, then set N=N-1.

[0181] 3) Sense the channel during the additional sensing slot duration. Here, if the additional sensing slot duration is idle, the process moves to step 4. If the additional sensing slot duration is not idle, proceed to step 5.

[0182] 4) If N=0, stop the corresponding process. Otherwise, go to step 2.

[0183] 5) Sense the channel until the additional delay duration T d A busy sensing time slot is detected within 1 second, or an additional delay duration T is added d All sensing slots are detected as idle.

[0184] 6) If the corresponding channel is in the additional delay duration T d If the sensor is sensed as idle during all sensing slot durations of the sensor, the process moves to step 4. Otherwise, proceed to step 5.

[0185] Figure 13 FIG. 4 is a diagram for explaining a DL CAP for unlicensed band transmission to which various embodiments of the present disclosure are applicable.

[0186] A type 1 downlink channel access procedure for unlicensed band transmission, to which various embodiments of the present disclosure are applicable, may be summarized as follows.

[0187] For downlink transmissions, a transmitting node (eg, a base station) may initiate a channel access procedure (CAP) (2010).

[0188] The base station may randomly select a backoff counter N within the contention window (CW) according to step 1. Here, the value of N is set to an initial value Ninit (2020). Ninit is selected to be any value between 0 and CWp.

[0189] Next, according to step 4, if the backoff counter value (N) is 0 (2030; Y), the base station ends the CAP process (2032). Then, the base station can perform Tx burst transmission (2034). In addition, if the backoff counter value is not 0 (2030; N), according to step 2, the base station decreases the backoff counter value by 1 (2040).

[0190] Next, the base station checks whether the channel is in an idle state (2050), and if the channel is in an idle state (2050; Y), checks whether the backoff counter value is 0 (2030).

[0191] Furthermore, in operation 2050, if the channel is not in an idle state (i.e., if the channel is in a busy state) (2050; N), the base station checks whether the corresponding channel is in an idle state during a delay duration (Td; 25 usec or more) longer than the sensing slot time (e.g., 9 usec) according to step 5 (2060). If the channel is in an idle state during the delay duration (2070; Y), the base station may resume the CAP process again.

[0192] For example, when the backoff counter value Ninit is 10 and the channel is determined to be in a busy state after the backoff counter value is reduced to 5, the base station senses the channel during the delay duration to determine whether it is in an idle state. Here, if the channel is in an idle state during the delay duration, the base station does not set the backoff counter value Ninit, but performs the CAP process again from the backoff counter value 5 (or from 4 after reducing the backoff counter value by 1).

[0193] Furthermore, if the channel is busy during the delay duration (2070; N), the base station re-executes step 2060 to check again whether the channel is idle during the new delay period.

[0194] In the event that the base station does not transmit after step 4 in the above process, the base station may transmit on the channel if the following conditions are met:

[0195] The base station prepares to transmit and the corresponding channel is sensed as idle for at least the sensing slot duration Ts1 and the channel is sensed as idle for all sensing slot durations of the delay duration Td immediately preceding the transmission.

[0196] In addition, when the base station senses the channel after preparing to transmit, the channel is not sensed as idle during the sensing slot duration Ts1, or when the channel is not sensed as idle during any one of the sensing slot durations of the delay duration Td immediately before the expected transmission, the base station proceeds to step 1 after sensing that the channel is idle during the sensing slot duration of the delay duration Td.

[0197] The delay duration Td consists of a period Tf (=16 us) immediately following mp consecutive sensing slot durations. Here, each sensing slot duration Ts1 is 9 us, and Tf includes an idle sensing slot duration Ts1 at the starting point of Tf.

[0198] Table 7 illustrates that mp, minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW size applied to CAP vary according to channel access priority class.

[0199] [Table 7]

[0200]

[0201] 3.2. Type 2 Downlink (DL) Channel Access Procedure

[0202] 3.2.1. Type 2A DL Channel Access Procedure

[0203] The base station may transmit immediately after the corresponding channel is sensed to be idle for at least the sensing duration Tshort d1 = 25 us. Here, Tshort d1 consists of the duration Tf (= 16 us) immediately following the duration of one sensing slot. Tf includes the sensing slot at the starting point of Tf. When two sensing slots in Tshort d1 are sensed to be idle, the channel is considered idle during Tshort d1.

[0204] 3.2.2. Type 2B DL ​​Channel Access Procedure

[0205] The base station may transmit immediately after the corresponding channel is sensed to be idle for Tf = 16 us. Tf includes the sensing slots occurring within the last 9 us of Tf. If the channel is sensed to be idle for at least 5 us in total and at least 4 us of sensing occurs in the sensing slots, then the channel is considered idle during Tf.

[0206] 3.2.3. Type 2C DL Channel Access Procedure

[0207] When the base station follows the procedure of this section to send a transmission, the base station does not sense the channel before sending the transmission. The duration corresponding to the transmission is up to 584 μs.

[0208] 4. Channel access procedure for transmission on multiple channels

[0209] A base station may have access to multiple channels through which transmissions are performed by one of the following Type A or Type B procedures.

[0210] 4.1. Type A multi-carrier access procedure

[0211] According to the process disclosed in this section, the base station i Channel access is performed on ∈ C. Here, C is a set of channels that the base station intends to transmit, i=0, 1, ..., q-1, and q is the number of channels that the base station intends to transmit.

[0212] For each channel c i Determine the counter N considered in the CAP and in this case the counter for each channel is given by Nc i To express.

[0213] 4.1.1. Type A1 Multi-channel Access Procedure

[0214] For each channel c i The counter N considered in the CAP is determined, and the counter for each channel is represented by Nc i express.

[0215] If the base station stops any channel c j ∈C, if it can be guaranteed in the long term (e.g., by adjusting the level) that there is no other technology sharing the channel, then for each channel c i (Here, c i with c j Different, c i ≠c j ), waiting for 4T s1 After an interval of i When an idle sensing time slot is detected later, the base station can restore Nc i of decreasing.

[0216] 4.1.2. Type A2 Multi-channel Access Procedure

[0217] According to the above description, the c for each channel can be determined j ∈C, and in this case, the counter for each channel is Nc j Here, c j It can mean having the maximum CW p For each channel c j , it can be configured as Nc i =Nc j .

[0218] When the base station stops targeting the determined Nc i When any channel of the base station sends, the base station reinitializes Nc for all channels i .

[0219] 4.2. Type B Multi-channel Access Procedure

[0220] The base station can select channel c as follows j ∈C.

[0221] - In multi-channel c j Before each transmission on ∈C, the base station uniformly randomly selects c from C j ,or,

[0222] - The base station selects c every 1 second j Not more than or equal to once.

[0223] Here, C is a set of channels that the base station intends to transmit, i=0, 1, ..., q-1, and q is the number of channels that the base station intends to transmit.

[0224] For channel c j The base station transmits on channel c according to the dedicativity described in Section 4.2.1 or Section 4.2.2 above and the process described in Section 3.1. j Perform channel access on the

[0225] For channel c i ≠c j On the transmission, on channel c j ∈C,

[0226] For each channel c i , the base station is in channel c i Sense channel c immediately before sending i Up to at least the sensing interval T mc = 28us. Then, the base station can sense channel c j Immediately after being idle for at least the sensing interval, i When the channel is sensed as idle for a given interval T mc Inner channel c j During all time intervals of idle sensing, channel c j Can be considered idle for T mc .

[0227] The base station is in channel c i ≠c j (Here, c i ∈C) does not execute the sending of T exceeding the above table 10 mcot,p Here, the channel c is used j The channel access parameters are used to determine T mcot,p .

[0228] In the procedures of this section, the channel frequencies of the channel set C selected by the gNB are a subset of one of the predefined channel frequency sets.

[0229] 4.2.1. Type B1 Multi-channel Access Procedure

[0230] Maintain a single CW for channel set C p value.

[0231] In order to determine the channel c j CW on channel access p , modify step 2 of the process described in Section 3.1 above as follows.

[0232] - When with all channels c jWhen at least Z=80% of the HARQ-ACK values ​​corresponding to the PDSCH transmissions in the reference subframe k of ∈C are determined to be NACKs, increment CW for all priority classes p∈{1, 2, 3, 4} p To the next higher allowed value. Otherwise, go to step 1.

[0233] 4.2.2. Type B2 Multi-channel Access Procedure

[0234] For each channel c i ∈C independently maintains CW p In order to determine the channel c i The CW p , can be used with channel c i Any PDSCH that is fully or partially overlapped. In order to determine the channel c j N init , using channel c j1 CW of ∈C p Here, c j1 is the channel with the largest CW among all channels in set C p channel.

[0235] 5. Uplink channel access process

[0236] The UE and the base station that schedules or configures UL transmission for the UE perform the following procedure for accessing the channel (performing LAAScell ​​transmission). In the following description, it is assumed that the UE and the base station are basically configured with a Pcell as a licensed frequency band and a Scell ​​as one or more unlicensed frequency bands, and the uplink CAP operation to which various embodiments of the present disclosure can be applied is described in detail. However, the uplink CAP operation can be similarly applied to the case where only the unlicensed frequency band is configured for the UE and the base station.

[0237] The UE may access a channel performing UL transmission according to a Type 1 or Type 2 UL channel access procedure.

[0238] Table 8 illustrates that mp, minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW size applied to CAP vary according to channel access priority class.

[0239] [Table 8]

[0240]

[0241] 5.1. Type 1 UL Channel Access Procedure

[0242] This section describes the channel access procedure performed from a UE where the duration spanned by the sensing slots sensed as idle prior to an uplink transmission is random. This section may apply to the following transmissions:

[0243] - PUSCH / SRS transmission scheduled and / or configured by the base station

[0244] - PUCCH scheduled and / or configured by the base station

[0245] - Random Access Procedure (RAP) related transmission

[0246] Figure 14 is a diagram for explaining a UL CAP for unlicensed band transmission to which various embodiments of the present disclosure can be applied.

[0247] A Type 1 UL CAP for a UE for unlicensed band transmission to which various embodiments of the present disclosure are applicable may be summarized as follows.

[0248] For uplink transmission, a transmitting node (eg, UE) may initiate a channel access procedure (CAP) to operate in an unlicensed band (2110).

[0249] The UE may randomly select a backoff counter N within the contention window (CW) according to step 1. Here, the value of N is set to an initial value Ninit (2120). Ninit is selected as any value between 0 and CWp.

[0250] Next, according to step 4, if the backoff counter value (N) is 0 (2130; Y), the UE terminates the CAP process (2132). Then, the UE can perform Tx burst transmission (2134). In addition, if the backoff counter value is not 0 (2130; N), according to step 2, the UE decreases the backoff counter value by 1 (2140).

[0251] Next, the UE checks whether the channel is in an idle state ( 2150 ), and if the channel is in an idle state ( 2150 ; Y), checks whether the backoff counter value is 0 ( 2130 ).

[0252] Furthermore, in operation 2150, if the channel is not in the idle state, that is, if the channel is in the busy state (2150; N), the UE checks whether the corresponding channel is in the idle state for a delay duration (Td; 25 usec or more) longer than the slot time (e.g., 9 usec) according to step 5 (2160). If the channel is in the idle state during the delay duration (2170; Y), the UE may resume the CAP process again.

[0253] For example, when the backoff counter value Ninit is 10 and the channel is determined to be in a busy state after the backoff counter value is reduced to 5, the UE senses the channel during the delay duration to determine whether it is in an idle state. Here, if the channel is in an idle state during the delay duration, the UE does not set the backoff counter value Ninit, but may perform the CAP process again from the backoff counter value 5 (or from 4 after decrementing the backoff counter value by 1).

[0254] Furthermore, if the channel is busy during the delay period (2170; N), the UE re-executes step 2160 to check again whether the channel is in an idle state during the new delay duration.

[0255] In the above process, if after step 4 of the above process, the UE does not send an UL transmission on the channel on which the transmission is performed, the UE may send an UL transmission on the channel if the following conditions are met:

[0256] - the UE is ready to transmit and the corresponding channel is sensed as idle for at least the sensing slot duration Tsl, and

[0257] - The channel is sensed as idle during all time slot durations of the delay duration Td immediately preceding the transmission.

[0258] In addition, if the channel is not sensed as idle within the sensing slot duration Ts1 when the UE first senses the channel after being ready to perform transmission, or if the corresponding channel is not sensed as idle during any sensing slot duration of the delay duration Td immediately before the intended transmission, the UE proceeds to step 1 after sensing the corresponding channel as idle during the slot duration of the delay duration Td.

[0259] The delay duration Td consists of a period Tf (=16 us) immediately following the mp continuous time slot duration. Here, each time slot duration Ts1 is 9 us, and Tf includes an idle time slot duration Ts1 at the starting point of Tf.

[0260] 5.2. Type 2 UL Channel Access Procedure

[0261] 5.2.1. Type 2A UL Channel Access Procedure

[0262] If the UE is instructed to perform a Type 2A UL channel access procedure, the UE uses a Type 2A channel access procedure for UL transmission. The UE may sense that the channel is idle for at least the sensing duration T short_ul =Send immediately after 25us. short_ul Includes a sensing time slot duration Tsl =9us followed by duration T f =16us. T f Included in T f The sensing time slot at the starting point of short_u1 If two sensing time slots in T are sensed as idle, the channel is short_ul The period is considered idle.

[0263] 5.2.2. Type 2B UL Channel Access Procedure

[0264] If the UE is instructed to perform a Type 2B UL channel access procedure, the UE uses the Type 2B channel access procedure for UL transmissions. The UE may transmit immediately after the corresponding channel is sensed to be idle for Tf = 16 us. Tf includes the sensing slots occurring within the last 9 us of Tf. If the channel is sensed to be idle for a total of at least 5 us, and at least 4 us of sensing occurs in the sensing slots, then the channel is considered idle during Tf.

[0265] 5.2.3. Type 2C UL Channel Access Procedure

[0266] If the UE is instructed to perform a Type 2C UL channel access procedure, the UE does not sense the channel before sending a transmission in order to send the transmission. The duration corresponding to the transmission is up to 584 us.

[0267] 6. Channel Access Procedure for UL Multi-Channel Transmission

[0268] If the UE:

[0269] - is scheduled to transmit on channel set C, then if the UL scheduling grant for UL transmission on channel set C indicates a Type 1 channel access procedure, if the UL transmission is scheduled to start transmission simultaneously for all channels in channel set C, and / or

[0270] - intends to perform uplink transmissions on resources configured on channel set C using a Type 1 channel access procedure, and

[0271] If the channel frequencies of channel set C are a subset of one of the pre-configured channel frequency sets, then:

[0272] -UE can use type 2 channel access procedure on channel c i ∈C and execute the sending.

[0273] --If adjacent to channel c j ∈C (where i≠j) before the UE on c i Type 2 channel access procedure is performed on

[0274] --If the UE has accessed channel c using the Type 1 channel access procedure j ,but

[0275] Before performing the Type 1 channel access procedure on any channel in channel set C, the UE uniformly randomly selects channel c from channel set C. j .

[0276] - If the UE fails to access any channel, the UE may select a channel c that is not within the bandwidth of the carrier whose bandwidth is scheduled or configured by the UL resource. i ∈C for sending.

[0277] Random Access (RA) Procedure

[0278] Figure 15 An example of a random access procedure is illustrated. Specifically, Figure 15 A contention-based random access procedure is illustrated.

[0279] First, the UE may transmit a random access preamble of Msg 1 as a random access procedure in UL through the PRACH.

[0280] Two different random access preamble sequence lengths are supported: a long sequence length of 839 for subcarrier spacings of 1.25 kHz and 5 kHz, and a short sequence length of 139 for subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, and 120 kHz.

[0281] Multiple preamble formats are defined by one or more RACH OFDM symbols and different cyclic prefixes (and / or guard times). The RACH configuration for the initial bandwidth of the primary cell (Pcell) is included in the system information of the cell and provided to the UE. The RACH configuration includes information about the subcarrier spacing 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 in the RACH time-frequency resource associated with the detected SSB or the selected SSB.

[0282] The threshold of the SSB associated with the RACH resource may be configured by the network, and the transmission or retransmission of the RACH preamble is performed based on the SSB, wherein the measured reference signal received power (RSRP) satisfies the threshold based on the SSB. For example, the UE may select one of the SSBs that meets the threshold and transmit or retransmit the RACH preamble based on the RACH resource associated with the selected SSB. For example, when retransmitting the RACH preamble, the UE may reselect one of the SSBs and retransmit the RACH preamble based on the RACH resource associated with the reselected SSB. That is, the RACH resource used for the retransmission of the RACH preamble may be the same as and / or different from the RACH resource used to transmit the RACH preamble.

[0283] When the base station (BS) receives a random access preamble from a UE, the BS sends a random access response (RAR) message (Msg 2) to the UE. The PDCCH that schedules the PDSCH carrying the RAR is CRC-scrambled and sent using the random access (RA) radio network temporary identifier (RNTI) (RA-RNTI). The UE that detects the PDCCH that is CRC-scrambled using the RA-RNTI can receive the RAR from the PDSCH scheduled by the DCI carried by the PDCCH. The UE checks whether the random access response information (i.e., Msg 1) of the preamble sent by the UE itself is in the RAR. Whether the random access information of Msg 1 sent by the UE itself exists can be determined by whether the random access preamble ID of the preamble sent by the UE exists. If there is no response to Msg 1, the UE can retransmit the RACH preamble within a predetermined number of times while performing power ramping. The UE calculates the PRACH transmit power for the retransmission of the preamble based on the most recent transmit power, power increment, and power ramp counter.

[0284] The random access response information includes a preamble sequence sent by the UE, a temporary cell RNTI (TC-RNTI) assigned by the base station to the UE that has attempted random access, uplink transmission time alignment information, uplink transmission power adjustment information, and uplink radio resource allocation information. When the UE receives its own random access response information on the PDSCH, the UE can obtain the timing advance information, initial UL grant, and TC-RNTI for UL synchronization. The timing advance information is used to control the uplink signal transmission timing. In order to better align the UE's PUSCH / PUCCH transmission with the subframe timing of the network side, the network (e.g., BS) obtains the timing advance information based on the timing information detected in the PRACH preamble received from the UE, and can send the corresponding timing advance information to the UE. The UE can send UL transmission as a random access procedure on the uplink shared channel based on the random access response information. Msg 3 may include an RRC connection request and a UE identifier. In response to Msg 3, the network may send Msg 4, which may be regarded as a contention resolution message on the DL. By receiving Msg 4, the UE can enter the RRC connected state.

[0285] In addition, a contention-free random access procedure can be used when the UE is in the process of switching to another cell or BS, or a contention-free random access procedure can be performed when requested by a command of the BS. The basic process of the contention-free random access procedure is similar to the contention-based random access procedure. However, unlike the contention-based random access procedure in which the UE randomly selects the preamble to be used from a plurality of random access preambles, in the case of a contention-free random access procedure, the preamble to be used by the UE (hereinafter, a dedicated random access preamble) is determined by the BS and allocated to the UE. Information about the dedicated random access preamble can be included in an RRC message (e.g., a handover command) or can be provided to the UE via a PDCCH command. When the random access procedure is initiated, the UE sends a dedicated random access preamble to the BS. When the UE receives a random access response from the BS, the random access procedure is completed.

[0286] As mentioned above, the UL grant in the RAR schedules the PUSCH transmission for the UE. The PUSCH that carries the initial UL transmission via the UL grant in the RAR is also called Msg 3 PUSCH. The content of the RAR UL grant starts at the MSB and ends at the LSB and is given in Table 9.

[0287] [Table 9]

[0288] RAR UL Permit Field Number of bits Frequency Hopping Flag 1 Msg 3PUSCH frequency resource allocation 12 Msg 3PUSCH time resource allocation 4 Modulation and Coding Scheme (MCS) 4 Transmit power control (TPC) for Msg 3PUSCH 3 CSI Request 1

[0289] The TPC command is used to determine the transmission power of Msg 3 PUSCH and is interpreted according to Table 10, for example.

[0290] [Table 10]

[0291] TPC Command Value [dB] 0 -6 1 -4 2 -2 3 0 4 2 5 4 6 6 7 8

[0292] During contention-free random access, the CSI request field in the RAR UL grant indicates whether the UE includes aperiodic CSI reporting in the corresponding PUSCH transmission. The subcarrier spacing for Msg 3 PUSCH transmissions is provided by RRC parameters. The UE will transmit PRACH and Msg 3 PUSCH on the same uplink carrier in the same serving cell. The UL BWP for Msg 3 PUSCH transmissions is indicated by System Information Block 1 (SIB1).

[0293] Multiplexing of short PUCCH and long PUCCH

[0294] Figure 16 A multiplexing configuration of a long Physical Uplink Control Channel (PUCCH) and a short PUCCH is illustrated.

[0295] PUCCH (e.g., PUCCH format 0 / 2) and PUSCH can be multiplexed using TDM or FDM schemes. Short PUCCH and long PUCCH from different UEs can be multiplexed using TDM or FDM schemes. Short PUCCH in one slot from a single UE can be multiplexed using TDM schemes. Short PUCCH and long PUCCH in one slot from a single UE can be multiplexed using TDM or FDM schemes.

[0296] ACK / NACK sending

[0297] Figure 17 This example illustrates the ACK / NACK sending process. Figure 17 , the UE can detect the PDCCH in time slot #n. Here, the PDCCH includes downlink scheduling information (e.g., DCI formats 1_0 and 1_1), and the PDCCH indicates the DL assignment to the PDSCH offset (K0) and the PDSCH-HARQ-ACK report offset (K1). For example, DCI formats 1_0 and 1_1 can include the following information.

[0298] - Frequency domain resource assignment: It indicates the RB set allocated to PDSCH.

[0299] - Time domain resource assignment: K0, which indicates the starting position (eg, OFDM symbol index) and length (eg, number of OFDM symbols) of the PDSCH in a slot.

[0300] -PDSCH to HARQ_feedback timing indicator: It indicates K1

[0301] Thereafter, the UE may send UCI in slot #(n+K1) through the PUCCH after receiving the PDSCH in slot #(n+K0) according to the scheduling information of slot #n. Here, the UCI includes a HARQ-ACK response for the PDSCH. If the PDSCH is configured to send up to 1 TB, the HARQ-ACK response may be configured with 1 bit. If the PDSCH is configured to send up to two TBs, the HARQ-ACK response may be configured with 2 bits when no spatial bundle is configured, and with 1 bit when spatial bundling is configured. When the HARQ-ACK transmission time for multiple PDSCHs is designated as slot #(n+K1), the UCI sent in slot #(n+K1) includes HARQ-ACK responses for multiple PDSCHs.

[0302] Figure 18 The SSB structure is illustrated. The UE can perform cell search, system information acquisition, beam alignment for initial access, DL measurement, etc. based on the SSB. SSB and SS / PBCH (Synchronization Signal / Physical Broadcast Channel) blocks can be used interchangeably.

[0303] Reference Figure 18 , SSB consists of PSS, SSS and PBCH. SSB is configured with four consecutive OFDM symbols, and PSS, PBCH, SSS / PBCH and PBCH are transmitted for each OFDM symbol. PSS and SSS are composed of 1 OFDM symbol and 127 subcarriers respectively, while PBCH is composed of 3 OFDM symbols and 576 subcarriers. Polarity coding and quadrature phase shift keying (QPSK) are applied to PBCH. PBCH consists of data RE and demodulation reference signal (DMRS) RE for each OFDM symbol. There are three DMRS REs for each RB, and there are three data REs between DMRS REs.

[0304] Cell Search

[0305] Cell search refers to the process in which the UE acquires time / frequency synchronization with a cell and detects the cell ID (e.g., physical layer cell ID (PCID)) of the cell. The PSS is used to detect a cell ID within a cell ID group, and the SSS is used to detect a cell ID group. The PBCH is used for SSB (time) index detection and half-frame detection.

[0306] The cell search process of the UE may be organized as shown in Table 11 below.

[0307] [Table 11]

[0308]

[0309] Figure 19 SSB transmission is illustrated.

[0310] The SSB is sent periodically according to the SSB periodicity. The SSB basic period assumed by the UE during the initial cell search is defined as 20ms. After cell access, the SSB periodicity can be set to one of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} by the network (e.g., base station). An SSB burst set is configured at the beginning of the SSB periodicity. The SSB burst set group is configured as a 5ms time window (i.e., half a frame), and the SSB can be sent up to L times within the SS burst set. The maximum number of SSB transmissions L can be given as follows according to the frequency band of the carrier. One time slot includes up to two SSBs.

[0311] - For the frequency range up to 3 GHz, L = 4

[0312] - For the frequency range from 3 GHz to 6 GHz, L = 8

[0313] - For the frequency range from 6 GHz to 52.6 GHz, L = 64

[0314] The temporal positions of SSB candidates in an SS burst set may be defined according to the SCS as follows: The temporal positions of SSB candidates are indexed in temporal order from 0 to L-1 (SSB index) within an SSB burst set (ie, half-frame).

[0315] - Case A - 15kHz SCS: The index of the starting symbol of the candidate SSB is given as {2, 8} + 14*n. If the carrier frequency is 3 GHz or less, n = 0, 1. If the carrier frequency is 3 GHz to 6 GHz, n = 0, 1, 2, 3.

[0316] - Case B - 30kHz SCS: The index of the starting symbol of the candidate SSB is given as {4, 8, 16, 20} + 28*n. If the carrier frequency is 3 GHz or less, n = 0. When the carrier frequency is 3 GHz to 6 GHz, n = 0, 1.

[0317] - Case C - 30kHz SCS: The index of the starting symbol of the candidate SSB is given as {2, 8} + 14*n. If the carrier frequency is 3 GHz or less, then n = 0, 1. If the carrier frequency is 3 GHz to 6 GHz, then n = 0, 1, 2, 3.

[0318] - Case D - 120kHz SCS: The indices of the starting symbols of the candidate SSBs are given as {4, 8, 16, 20} + 28*n. For carrier frequencies greater than 6GHz, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

[0319] - Case E - 240kHz SCS: The indices of the starting symbols of the candidate SSBs are given as {8, 12, 16, 20, 32, 36, 40, 44} + 56*n. For carrier frequencies greater than 6GHz, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0320] Figure 20 This illustrates how the UE obtains information about DL time synchronization.

[0321] The UE can acquire DL synchronization by detecting SSBs. The UE can identify the structure of the SSB burst set based on the detected SSB index and thus detect the symbol / time slot / half-frame boundary. The SFN information and half-frame indication information can be used to identify the frame / half-frame number to which the detected SSB belongs.

[0322] Specifically, the UE can obtain 10-bit SFN (System Frame Number) information (s0 to s9) from the PBCH. Of the 10-bit SFN information, 6 bits are obtained from the Master Information Block (MIB) and the remaining 4 bits are obtained from the PBCH Transport Block (TB).

[0323] Next, the UE can obtain 1-bit half-frame indication information (c0). When the carrier frequency is 3 GHz or lower, the half-frame indication information can be implicitly signaled using the PBCH DMRS. The PBCH DMRS indicates 3 bits of information by using one of the eight PBCH DMRS sequences. Therefore, in the case of L=4, after indicating the SSB index among the 3 bits that can be indicated using the 8 PBCH DMRS sequences, the remaining one bit can be used for the half-frame indication.

[0324] Finally, the UE can obtain the SSB index based on the DMRS sequence and the PBCH payload. The SSB candidates are indexed from 0 to L–1 in time order within the SSB burst set (i.e., half-frame). When L=8 or 64, 8 different PBCH DMRS sequences can be used to indicate the LSB (least significant bit) 3 bits (b0 to b2) of the SSB index. When L=64, the MSB (most significant bit) 3 bits (b3 to b5) of the SSB index are indicated by PBCH. When L=2, four different PBCH DMRS sequences can be used to indicate the LSB2 bits (b0, b1) of the SSB index. When L=4, after indicating the SSB index among the 3 bits that can be indicated using 8 PBCH DMRS sequences, the remaining one bit can be used for half-frame indication (b2).

[0325] Get system information

[0326] Figure 21 The system information (SI) acquisition process is illustrated. The UE can acquire AS / NAS information through the SI acquisition process. The SI acquisition process can be applied to UEs in the RRC_IDLE state, RRC_INACTIVE state, and RRC_CONNECTED state.

[0327] SI is divided into MIB (Master Information Block) and multiple SIBs (System Information Blocks). MIB and multiple SIBs can be divided into minimum SI and other SI. Here, minimum SI can be composed of MIB and SIB1, and includes information for obtaining basic information and other information required for initial access. Here, SIB1 can be called remaining minimum system information (RMSI). For more details, please refer to the following.

[0328] -MIB includes information / parameters related to SIB1 (SystemInformationBlockType1) reception and is transmitted through the PBCH of the SSB. For initial cell selection, the UE assumes that the half-frame with the SSB is repeated with a periodicity of 20ms. The UE can check whether there is a control resource set (CORESET) for the Type0-PDCCH common search space based on the MIB. The Type0-PDCCH common search space is a type of PDCCH search space and is used to send PDCCHs that schedule SI messages. When a Type0-PDCCH common search space exists, the UE can determine, based on information in the MIB (e.g., pdcch-ConfigSIB1), (i) multiple consecutive RBs and one or more consecutive symbols constituting the CORESET, and (ii) the PDCCH timing (i.e., the time domain position for receiving the PDCCH). When there is no Type0-PDCCH common search space, pdcch-ConfigSIB1 provides information about the frequency positions where SSB / SIB1 exists and the frequency ranges where SSB / SIB1 does not exist.

[0329] -SIB1 includes information related to the availability and scheduling (e.g., transmission periodicity, SI window size) of the remaining SIBs (hereinafter, SIBx, x is an integer greater than or equal to 2). For example, SIB1 can inform whether SIBx is broadcast periodically or provided by an on-demand method based on the UE's request. When SIBx is provided by the on-demand method, SIB1 may include information required for the UE to perform the SI request. SIB1 is transmitted through PDSCH, the PDCCH that schedules SIB1 is transmitted through the Type0-PDCCH common search space, and SIB1 is transmitted through the PDSCH indicated by the PDCCH.

[0330] - SIBx is included in the SI message and transmitted through the PDSCH. Each SI message is transmitted within a periodically occurring time window (ie, SI window).

[0331] Beam alignment

[0332] Figure 22 Multi-beam transmission of SSB is illustrated.

[0333] Beam scanning refers to the transmission reception point (TRP) (e.g., base station / cell) changing the beam (direction) of the radio signal according to time (hereinafter, beam and beam direction can be used interchangeably). Beam scanning can be used to periodically transmit SSBs. In this case, the SSB index is implicitly linked to the SSB beam. The SSB beam can be changed in units of SSB (index) or in units of SSB (index) groups. In the latter case, the SSB beam remains the same within the SSB (index) group. That is, the transmission beam direction of the SSB is repeated in multiple consecutive SSBs. Depending on the frequency band to which the carrier belongs, the maximum number of transmissions L of the SSB in the SSB burst set has a value of 4, 8, or 64. Therefore, the maximum number of SSB beams in the SSB burst set can also be given as follows according to the frequency band of the carrier.

[0334] -For frequency range up to 3 GHz, maximum number of beams = 4

[0335] -For the frequency range from 3 GHz to 6 GHz, the maximum number of beams = 8

[0336] -For the frequency range from 6 GHz to 52.6 GHz, the maximum number of beams = 64

[0337] *When multi-beam transmission is not applied, the number of SSB beams is one.

[0338] When a UE attempts to initially access a base station, the UE can align the beam with the base station based on the SSB. For example, the UE identifies the best SSB after performing SSB detection. Thereafter, the UE can use the PRACH resource linked to the index (i.e., beam) of the best SSB / corresponding to the index (i.e., beam) of the best SSB to send a RACH preamble to the base station. Even after initial access, the SSB can be used to align the beam between the base station and the UE.

[0339] Channel measurement and rate matching

[0340] Figure 23 A method of notifying the actually transmitted SSB (SSB_tx) is illustrated.

[0341] A maximum of L SSBs can be transmitted in an SSB burst set, and the number / position of SSBs actually transmitted may vary for each base station / cell. The number / position of SSBs actually transmitted is used for rate matching and measurement, and information about the SSBs actually transmitted is indicated as follows.

[0342] - Cases related to rate matching: It can be indicated by UE-specific RRC signaling or RMSI. UE-specific RRC signaling includes a complete (e.g., length L) bitmap in both the frequency range below 6 GHz and above 6 GHz. In addition, as shown in the figure, RMSI includes a complete bitmap below 6 GHz and a compressed bitmap above 6 GHz. Specifically, a group bitmap (8 bits) + an intra-group bitmap (8 bits) can be used to indicate information about the SSB actually transmitted. Here, the resources (e.g., REs) indicated by UE-specific RRC signaling or RMSI are reserved for SSB transmission, and PDSCH / PUSCH, etc. can consider the SSB resources for rate matching.

[0343] - Measurement-related cases: In the case of RRC connected mode, the network (e.g., base station) can indicate the SSB set to be measured during the measurement period. The SSB set can be indicated for each frequency layer. If there is no indication related to the SSB set, the default SSB set is used. The default SSB set includes all SSBs in the measurement period. The SSB set can be indicated using a full (e.g., length L) bitmap of RRC signaling. In the case of RRC idle mode, the default SSB set is used.

[0344] Figure 24 This section illustrates the structure of a radio frame used in NR.

[0345] In NR, uplink and downlink transmissions are configured as frames. A radio frame has a length of 10 ms and is defined as two half frames (HF) of 5 ms. A half frame is defined as 5 subframes (SF) of 1 ms. 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). Each time slot includes 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP). 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. Here, the symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or DFT-s-OFDM symbols).

[0346] Table 12 illustrates 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 when a normal CP is used.

[0347] [Table 12]

[0348] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot <!-- 30 -->]]> 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

[0349] *N slot symb : Number of symbols in a time slot * N frame,u slot: Number of time slots in a frame

[0350] *N subframe,u slot : Number of time slots in a subframe

[0351] Table 13 illustrates that when the extended CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to the SCS.

[0352] [Table 13]

[0353] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 60KHz (u=2) 12 40 4

[0354] In NR systems, OFDM(A) parameter sets (e.g., SCS, CP length, etc.) can be configured differently between multiple cells aggregated into one UE. Therefore, the (absolute time) duration (for convenience, referred to as TU (time unit)) of a time resource (e.g., SF, time slot, or TTI) consisting of the same number of symbols can be configured differently between the aggregated cells.

[0355] Figure 25 The time slot structure of the NR frame is illustrated. A time slot includes multiple symbols in the time domain. For example, in the case of normal CP, one time slot includes 14 symbols, but in the case of extended CP, one time slot includes 12 symbols. A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) is defined as a plurality of (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) is defined as a plurality of consecutive (P)RBs in the frequency domain and can correspond to a parameter set (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 4) BWPs. Data communication is performed through activated BWPs, and only one BWP can be activated for one UE. Each element in the resource grid is called a resource element (RE) and can map a complex symbol.

[0356] Figure 26The structure of a self-contained slot is illustrated. In the NR system, a frame is characterized by a self-contained structure in which a DL control channel, DL or UL data, and a UL control channel can all be included in one slot. For example, the first N symbols in a slot can be used to send a DL control channel (hereinafter referred to as a DL control region), and the last M symbols in a slot can be used to send a UL control channel (hereinafter referred to as a UL control region). N and M are each integers greater than or equal to 0. The resource region between the DL control region and the UL control region (hereinafter referred to as the data region) can be used for DL ​​data transmission or UL data transmission. As an example, the following configuration can be considered. Each duration is listed in chronological order.

[0357] 1. DL configuration only

[0358] 2. UL configuration only

[0359] 3. Hybrid UL-DL configuration

[0360] -DL region + guard period (GP) + UL control region

[0361] -DL control area + GP + UL area

[0362] *DL area: (i) DL data area, (ii) DL control area + DL data area

[0363] *UL area: (i) UL data area, (ii) UL data area + UL control area

[0364] The PDCCH may be sent in the DL control region, and the PDSCH may be sent in the DL data region. The PUCCH may be sent in the UL control region, and the PUSCH may be sent in the UL data region. In the PDCCH, downlink control information (DCI) (e.g., DL data scheduling information, UL data scheduling information, etc.) may be sent. In the PUCCH, uplink control information (UCI) (e.g., ACK / NACK (positive acknowledgement / negative acknowledgement) information for DL ​​data, CSI (channel state information) information, SR (scheduling request), etc.) may be sent. The GP provides a time gap in the process of the base station and the UE switching from a transmit mode to a receive mode or in the process of switching from a receive mode to a transmit mode. Some symbols of the time of switching from DL to UL in the subframe may be configured as GPs.

[0365] Bandwidth Part (BWP)

[0366] In the NR system, up to 400MHz per carrier can be supported. If a UE operating on such a wideband carrier always operates with the radio frequency (RF) module turned on for the entire carrier, the UE battery consumption may increase. Alternatively, when considering multiple use cases operating on one wideband carrier (e.g., eMBB, URLLC, mMTC, V2X, etc.), different parameter sets (e.g., subcarrier spacing) for each frequency band within the corresponding carrier may be supported. Alternatively, the capacity of the maximum bandwidth may be different for each UE. Taking the above into account, the base station may instruct the UE to operate only in part of the bandwidth rather than the entire bandwidth of the wideband carrier, and the part of the bandwidth is called a bandwidth part (BWP). In the frequency domain, a BWP is a subset of contiguous common resource blocks defined by a parameter set μi in a bandwidth part i on a carrier, and a parameter set (e.g., subcarrier spacing, CP length, slot / mini-slot duration) may be configured.

[0367] In addition, the base station can configure one or more BWPs in a carrier configured for the UE. Alternatively, when UEs are concentrated in a specific BWP, some UEs can be moved to another BWP for load balancing. Alternatively, considering frequency-domain inter-cell interference cancellation between adjacent cells, the middle portion of the spectrum from the entire bandwidth can be excluded, and two edge BWPs of the cell can be configured in the same time slot. That is, the base station can configure at least one DL / UL BWP for a UE associated with a wideband carrier, and at a specific time activate (via L1 signaling as a physical layer control signal, a MAC control element (CE) as a MAC layer control signal, or RRC signaling, etc.) at least one DL / UL BWP among the configured DL / UL BWPs, instruct (via L1 signaling, MAC CE, or RRC signaling, etc.) to switch to another configured DL / UL BWP, or set a timer value and cause the UE to switch to the determined DL / UL BWP when the timer expires. Here, to instruct switching to another configured DL / UL BWP, DCI format 1_1 or DCI format 0_1 ​​can be used. The activated DL / UL BWP is specifically referred to as the active DL / UL BWP. In situations such as when the UE is in the initial access process or before the UE's RRC connection is established, the UE may not receive a configuration for the DL / UL BWP. In this situation, the DL / UL BWP assumed by the UE is referred to as the initial active DL / UL BWP.

[0368] Furthermore, here, the DL BWP is a BWP for transmitting and receiving downlink signals such as PDCCH and / or PDSCH, and the UL BWP is a BWP for transmitting and receiving uplink signals such as PUCCH and / or PUSCH.

[0369] In an NR system, downlink channels and / or downlink signals may be transmitted / received within an active DL downlink bandwidth part (BWP). Additionally, uplink channels and / or uplink signals may be transmitted / received within an active UL uplink bandwidth part (BWP).

[0370] Before describing in detail, reference will be made to Figures 27 and 28 An example of operations of a UE and a base station according to an embodiment of the present disclosure will be described.

[0371] Figure 27 1 is a diagram for explaining an example of an operation implementation of a UE according to the present disclosure. Figure 27 , the UE may transmit a first physical random access channel (PRACH) preamble via message A (S2701). And in response to message A, it may receive a random access response (RAR) via message B related to contention resolution (S2703). Here, the specific method by which the UE performs the random access procedure in S2701 to S2703 may be based on the embodiments and features to be described below.

[0372] also, Figure 27 The UE can be Figures 1 to 4 Any of the various wireless devices disclosed. For example, Figure 27 The UE can be Figure 1 The first wireless device 100 or Figure 2 In other words, Figure 27 The operation processing can be done by Figures 1 to 4 The invention may be executed and implemented by any of the various wireless devices illustrated.

[0373] Figure 28 1 is a diagram for explaining an example of an operation implementation of a base station according to the present disclosure. Figure 28 , the base station may receive a first physical random access channel (PRACH) preamble code through message A (S2801), and in response to message A, may send a random access response (RAR) through message B related to contention resolution (S2803). Here, the specific method of the base station performing the random access procedure in S2801 to S2803 may be based on the embodiments and features described below.

[0374] also, Figure 28 The base station can be Figures 1 to 4 Any of the various wireless devices disclosed. For example, Figure 28 The base station can be Figure 1 The second wireless device 200 or Figure 2 In other words, Figure 28 The operation processing can be done by Figures 1 to 4 The invention may be executed and implemented by any of the various wireless devices illustrated.

[0375] In LTE and / or NR networks, a UE can perform UL transmission through a random access procedure (RACH procedure) without receiving a direct uplink (UL) transmission schedule from a given base station or cell. From the UE's perspective, the random access process in LTE and / or NR systems is a four-step process, including the following steps: 1) transmission of a random access preamble, 2) reception of a message (Msg) 2 corresponding to a random access response (RAR), 3) transmission of a Msg 3 including a physical uplink shared channel (PUSCH), and 4) reception of a Msg 4 including information on contention resolution.

[0376] Here, Msg 2 is a message for the base station that receives the random preamble to allocate such UL resources, that is, the UL resources are to be used by the UE that has sent the corresponding preamble for sending Msg 3. Through Msg 3, the UE can send information related to the connection request, etc. and its own identification information (for example, the International Mobile User Identity (IMSI) or the Temporary Mobile User Identity (TMSI)). Upon receiving Msg 3, the base station can send the identification information of the corresponding UE and the information required for random access through Msg 4, thereby preventing possible conflicts between different UEs during the random access procedure and completing the random access procedure of the corresponding UE.

[0377] Unlike the RACH procedure in existing LTE and NR rel-15, which is configured in four steps as described above, the newly introduced NR rel-16 is studying a two-step RACH procedure to simplify the processing delay of the four steps and utilize the RACH procedure even in small cells or unlicensed bandwidth. In the two-step RACH, the steps of transmitting Message 3 (Msg 3) containing the Physical Uplink Shared Channel (PUSCH) and transmitting Msg 4 containing the contention resolution message, which are required in the existing four-step RACH, are omitted. Instead, in the first step of the random access procedure, the UE directly transmits a message corresponding to the preamble together with Msg 3 as Msg A to the base station. In response to Msg A, the base station transmits a message corresponding to the RAR together with Msg 4 as Msg B to the UE. Upon receiving Msg B, the UE decodes Msg B and completes the random access procedure, thereafter performing data transmission / reception.

[0378] Figure 29 This is a diagram illustrating the basic process of 2-step RACH. Figure 29, the UE may receive 2-step RACH-related configuration information included in the broadcast system information from the base station (S2901). Upon receiving the 2-step RACH-related configuration information, the UE sends Msg A including a RACH preamble (or PRACH preamble) and a PUSCH based on the configuration information to perform a random access procedure for the base station (S2903). Here, the RACH preamble and the PUSCH may be sent at predetermined intervals in the time domain or may be sent continuously, and the corresponding PUSCH includes the identifier (ID) information of the UE. The base station may detect the preamble and may predict and receive the PUSCH at corresponding intervals or continuously. After receiving an access request and / or response from an upper layer based on the ID information of the UE sent through the PUSCH, the base station sends Msg B including information such as RAR and contention resolution as a response to Msg A to the UE (S2905). Thereafter, depending on whether the UE receives Msg B, the UE completes access to the base station in the same or similar manner as after receiving Msg 4 in the existing 4-step RACH procedure, and can transmit and receive data with the base station.

[0379] In NR, since the UE can perform a random access procedure in an unlicensed band, the Listen Before Talk (LBT) process required for signal transmission and reception in the unlicensed band can also be applied to the signal transmission and reception of the random access procedure. That is, in the NR-Unlicensed Spectrum (NR-U) system, before the base station and the UE transmit / receive signals, LBT is always performed to check the idle or busy state of the transmission / reception channel, and for the 2-step RACH procedure in the unlicensed band, LBT can also be performed during the transmission and reception of Msg A and Msg B.

[0380] Specifically, since the transmission of Msg A in the 2-step RACH procedure includes the transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH, the random access procedure performed thereafter may be changed depending on the success or failure of the LBT for the Msg A PUSCH after the transmission of the Msg A PRAPRACH preamble. For example, if the UE transmits the Msg A PRACH preamble, then successfully performs LBT on the Msg A PUSCH and transmits the Msg A PUSCH without any particular problem, the base station correctly receives both the Msg A PRACH preamble and the Msg A PUSCH, and transmits Msg B including contention resolution information to the UE, thereby completing the 2-step RACH procedure. Otherwise, if the UE fails to perform LBT on MsgA PUSCH after sending the Msg A PRACH preamble, the UE cannot send Msg A PUSCH, and the base station that only receives the Msg A PRACH preamble but does not receive the Msg A PUSCH can indicate to fall back to Msg 3 through Msg B, so that the UE can switch to the 4-step RACH process.

[0381] Therefore, for the 2-step RACH procedure in the unlicensed band, whether LBT for Msg A PUSCH succeeds or fails should be considered in Msg A PUSCH transmission and subsequent Msg B reception, and in particular, it may be necessary to avoid processing delays that occur when LBT fails. Below, in order to maintain the advantage of fast access of the 2-step RACH procedure, a method of configuring a single or multiple resources for Msg A PUSCH in consideration of LBT failure will be described, and a method of configuring the receive window (or contention resolution timer; CR timer) of Msg B based on the configured resources will be described.

[0382] 1. Case where RACH timing and Msg APUSCH timing have a one-to-one mapping relationship

[0383] For the transmission of Msg A, the RACH opportunity (RO) in which the Msg A PRACH preamble is transmitted and the PUSCH opportunity (PO) in which the Msg A PUSCH is transmitted can be mapped one to one. Therefore, when the UE transmits the Msg A PRACH preamble, the Msg A PUSCH opportunity corresponding to the transmitted Msg A PRACH preamble is configured as one, and for this one Msg A PUSCH opportunity, it is determined whether to transmit the Msg A PUSCH according to the success or failure of LBT.

[0384] The window or timer for the UE to receive Msg B can be configured as follows: 1) If LBT is successful, the timer starts or the window is configured after the Msg APUSCH opportunity, or if LBT fails, the window is not configured or the timer does not start. Alternatively, it can be configured as follows: 2) Regardless of whether LBT is successful or failed, the timer always starts or the window is always configured after the Msg A PUSCH opportunity.

[0385] Here, the UE selects the Msg A PRACH preamble for the 2-step RACH procedure, and even if the UE succeeds in LBT for the Msg A PUSCH, or regardless of whether LBT succeeds or fails, in the event of a situation where the channel state deteriorates, such as at one Msg A PUSCH opportunity, the UE can predict the detection error probability for the Msg A PUSCH for itself and can transmit only the Msg A PRACH preamble without transmitting the Msg A PUSCH. That is, whether the Msg A PUSCH is transmitted can be changed according to the success or failure of LBT or according to the UE's independent determination and selection of whether to transmit or not transmit the Msg A PUSCH.

[0386] In the case where it can be determined whether to send Msg A PUSCH as described above, the start time of the window or timer for receiving Msg B can be configured as in the following example, and here, among the following examples, those examples that can be utilized regardless of the success or failure of LBT are not limited to being applied to the NR-U system and can be applied to the authorized carrier.

[0387] (1) Example 1: When LBT is successful, at least one symbol from the last symbol of the PUSCH opportunity After the first symbol, set the window or timer start time

[0388] Example 1 is a method of configuring a window or timer for receiving Msg B only when LBT succeeds and Msg A PUSCH can be transmitted, and not configuring a window or timer for receiving Msg B when LBT fails and Msg A cannot be transmitted. That is, even if there is an Msg APUSCH opportunity corresponding to the Msg A PUSCH preamble transmitted by the UE, if LBT fails, Msg A PUSCH transmission in the corresponding Msg APUSCH opportunity is not performed, and thus the window or timer for receiving Msg B is not started. In addition, if LBT succeeds, Msg A PUSCH transmission in the corresponding Msg APUSCH opportunity is performed normally, and the window or timer for receiving Msg B may also be started.

[0389] Here, the start time of the window or timer for receiving Msg B may be a symbol that is at least one symbol after the last symbol of the Msg A PUSCH opportunity corresponding to the Msg APRACH preamble transmitted by the UE. In other words, the window or timer for receiving Msg B may be configured to start at an interval of at least one symbol from the Msg A PUSCH opportunity in symbol units. In addition, under the premise of configuring resources for monitoring Msg B, the start time of the window or timer may be the first symbol of the resources for monitoring Msg B. Here, the resources for monitoring Msg B may be resources corresponding to the earliest CORESET of the Type 1-PDCCH common search space of the PDCCH set for the UE to receive Msg B.

[0390] Therefore, in the case where a UE that has sent a Msg A PRACH preamble succeeds in LBT and can then send a Msg APUSCH, the window or timer configured to receive Msg B may start from the first symbol of the resource used to monitor Msg B, and the corresponding start time may be a time point after at least one symbol from the last symbol of the Msg A PUSCH opportunity.

[0391] Figure 30 is a diagram illustrating an example of configuring the reception window of Msg B according to the success or failure of LBT for Msg A PUSCH transmission. Figure 30 In (A), for the PO corresponding to the RO related to the Msg A PRACH preamble sent by the UE, when the LBT for sending Msg A PUSCH fails, the UE does not send Msg A PUSCH and does not configure a window or timer for receiving Msg B. In addition, Figure 30 In (B), for the PO corresponding one-to-one to the RO related to the Msg A PRACH preamble sent by the UE, when the LBT for Msg A PUSCH transmission is successful, the UE transmits Msg A PUSCH and configures a window or timer for receiving Msg B. Here, the window or timer configured to receive Msg B starts from the first symbol of the resource used to monitor Msg B, and the corresponding start time is a time point after at least one symbol from the last symbol of the PUSCH opportunity.

[0392] (2) Example 2: After at least one symbol from the last symbol of the PUSCH opportunity, with LBT successful or Failure to set the start time of the window or timer from the first symbol independently

[0393] Unlike Example 1, Example 2 is a method of setting a window or timer for receiving Msg B even if the UE fails to transmit Msg A PUSCH due to LBT failure for Msg A PUSCH. That is, if there is a PUSCH opportunity corresponding to the Msg A PUSCH preamble transmitted by the UE, the reception window or timer for Msg B can be started regardless of whether LBT succeeds or fails, and the UE can expect to receive Msg B. The method of Example 2 can be applied without distinguishing between licensed carriers and unlicensed carriers.

[0394] In Example 2, the start time of the window or timer for receiving Msg B may be a symbol after at least one symbol from the last symbol of the Msg A PUSCH opportunity corresponding to the Msg A PRACH preamble transmitted by the UE. In other words, the window or timer for receiving Msg B may be configured to start at an interval of at least one symbol from the Msg APUSCH opportunity in symbol units. In addition, under the premise of configuring resources for monitoring Msg B, the start time of the window or timer may be the first symbol of the resources for monitoring Msg B. Here, the resources for monitoring Msg B may be resources corresponding to the earliest CORESET of the Type 1-PDCCH common search space of the PDCCH set for the UE to receive Msg B.

[0395] When a UE that has transmitted a Msg A PRACH preamble fails to transmit a Msg A PUSCH due to LBT failure, or does not transmit a Msg A PUSCH based on an independent determination of a channel state, the UE may expect to receive a fallback RAR including uplink (UL) grant information for transmitting a Msg 3 through Msg B. The base station also transmits a fallback RAR including UL grant information to the UE through Msg B, thereby causing the UE to fall back on the transmission of Msg 3 together with the 4-step RACH procedure. Here, even if the random access preamble index (RAPID) included in the detected Msg_A PRACH preamble is a RAPID for a 2-step RACH procedure, and if the base station fails to decode the Msg_A PSCH for a specific period of time, the base station may assume that the UE has failed LBT and has not transmitted the Msg A PSCH, and may transmit a fallback RAR to the UE.

[0396] A UE that expects to receive a fallback RAR due to failure to transmit Msg A PUSCH may ignore a successful RAR including its own RAPID even if it detects one, and may expect to receive a fallback RAR whose RAPID matches its own RAPID during a given window or timer duration. If the UE does not receive a RAR within the window or timer expiration time, the UE may perform a random access resource selection procedure for random access after a specific back-off time, up to a specified maximum number of transmissions, and then may perform a radio link failure (RLF) procedure.

[0397] On the other hand, if the UE that has transmitted the Msg A PRACH preamble succeeds in LBT and transmits Msg APUSCH, the UE can expect to receive a successful RAR including information on contention resolution through Msg B, and can expect its RAPID and a specific value (e.g., a UE-specific identifier (UE-identifier; UE-ID) to be included in the content of Msg B. The base station can also notify the UE that the 2-step RACH procedure of the UE can be successfully performed by transmitting a successful RAR including information on contention resolution to the UE through Msg B. If the UE does not identify its RAPID and UE-ID through Msg B, the UE continues to perform blind decoding until the reception window or timer of Msg B expires. Here, if the UE fails to identify the RAPID and UE-ID by the expiration time, the UE can perform a resource selection procedure for random access after a specific backoff time until the specified maximum number of transmissions, and then can perform a radio link failure procedure.

[0398] The above example can be similarly applied to a situation where multiple UEs perform a 2-step RACH procedure with respect to one base station. In the case where there are two UEs that simultaneously select the Msg A PUSCH preamble including the same RAPID, it is possible that one UE transmits Msg A PUSCH while the other UE fails to transmit Msg A PUSCH. Here, as described above, the UE that transmits Msg A PUSCH expects to receive a successful RAR and also expects its RAPID and UE-ID to be included in the content of Msg B. If the UE does not identify its RAPID and UE-ID through Msg B, the UE continues to perform blind decoding according to the time of the window or timer expiration. If the UE does not identify its RAPID and UE-ID until the expiration, the UE can perform a resource selection procedure for random access after the backoff time and the radio link failure (RLF) procedure. On the other hand, the UE that failed to transmit Msg A PUSCH expects a fallback RAR that matches its RAPID during the window or timer duration as described above, and even if it detects a successful RAR including its own RAPID, it can ignore it. A UE that fails to receive the RAR by the time of expiration of the window or timer may perform a resource selection procedure for random access after a specific backoff time and a radio link failure procedure.

[0399] Figure 31 : is a diagram illustrating an example of configuring the reception window of Msg B regardless of the success or failure of LBT for Msg A PUSCH transmission. Figure 31 In (A), for the PO corresponding to the RO related to the Msg A PRACH preamble sent by the UE, even if the LBT for Msg A PUSCH transmission fails and the UE does not send Msg A PUSCH, a window or timer for receiving Msg B can be configured. Figure 31 In (B), for the PO corresponding to the RO related to the Msg A PRACH preamble sent by the UE, if the LBT sent for Msg A PUSCH is successful, the UE sends Msg APUSCH and configures a window or timer for receiving Msg B. Here, Figure 31 (A) or Figure 31 The window or timer configured to receive Msg B in (B) starts from the first symbol of the resource used to monitor Msg B, and the corresponding start time may be a time point after at least one symbol from the last symbol of the PUSCH opportunity.

[0400] 2. RACH Timing and Msg A Case where PUSCH opportunities have a one-to-many mapping relationship

[0401] For Msg A transmission, a RACH opportunity (RO) in which a Msg A PRACH preamble is transmitted may be mapped to multiple PUSCH opportunities (PO) in which Msg A PUSCH is transmitted. Here, the multiple Msg A PUSCH opportunities may be allocated continuously in a time division multiplexing (TDM) manner without time gaps between the Msg A PUSCH opportunities. Alternatively, the multiple Msg A PUSCH opportunities may be allocated with constant time gaps.

[0402] The one-to-many mapping relationship between RACH opportunities and Msg A PUSCH opportunities can be configured according to various schemes. As a simple example, the preambles used for all 2-step RACH procedures can be mapped to all multiple Msg A PUSCH opportunities respectively.

[0403] Alternatively, as another example, the preambles used for the 2-step RACH process can be divided into N subsets, and the number of Msg A PUSCH opportunities mapped to the preambles can be configured differently for each subset. That is, with respect to the preambles divided into N subsets, 1) in the case of a subset including preambles corresponding to #0 to #A-1, each preamble can be mapped to one Msg A PUSCH opportunity to form a one-to-one mapping relationship, and 2) in the case of a subset including preambles corresponding to #A to #B-1, each preamble can be mapped to two Msg A PUSCH opportunities to form a one-to-two mapping relationship. In addition, 3) in the case of a subset including preambles corresponding to #B to #C-1, each preamble can be mapped to three Msg A PUSCH opportunities to form a one-to-three mapping relationship, and further settings for the mapping relationship are also possible.

[0404] In the above example where the number of Msg A PUSCH opportunities mapped to preambles is configured differently for each subset, the preambles included in the subset 1) have a one-to-one mapping relationship with the Msg A PUSCH opportunities. Therefore, one PUSCH opportunity corresponding to the transmitted PRACH preamble is configured, and for each corresponding PUSCH opportunity, whether to transmit the Msg A PUSCH is determined based on the success or failure of LBT. The preambles included in the subset 2) have a one-to-two mapping relationship with the Msg A PUSCH opportunities. Therefore, two PUSCH opportunities corresponding to the transmitted PRACH preamble are configured, and for each corresponding PUSCH opportunity, whether to transmit the Msg A PUSCH is determined based on the success or failure of LBT. Similarly, the preambles included in the subset 3) have a one-to-three mapping relationship with the Msg A PUSCH opportunities. Therefore, three PUSCH opportunities corresponding to the transmitted PRACH preamble are configured, and for each corresponding PUSCH opportunity, whether to transmit the Msg A PUSCH is determined based on the success or failure of LBT.

[0405] Since multiple LBT attempts can be made as the number of resources corresponding to the PUSCH opportunities transmitted corresponding to the PRACH preamble increases, the probability of Msg A PUSCH transmission can be increased despite the failure of LBT. That is, the probability of Msg APUSCH transmission can be changed for each subset, and considering the channel state or priority of the signal to be transmitted, the UE can select a subset including preambles with a relatively high Msg A PUSCH transmission probability or a low Msg A PUSCH transmission probability. For example, the UE can select a subset based on the reference signal received power (RSRP) of a reference signal such as a received synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS), or can select a subset based on a priority criterion such as the size of the Msg APUSCH to be transmitted. Based on the selected subset, the UE can perform LBT for the PUSCH opportunities corresponding to the preambles included in the subset, attempt to transmit Msg A PUSCH, and configure a window or timer for receiving Msg B.

[0406] In this case, for a preamble with a one-to-one mapping relationship, Msg A PUSCH may be transmitted according to Example 1 or Example 2 above, and a window or timer for receiving Msg B may be configured. In the case where multiple PUSCH opportunities are mapped to one preamble instead of a one-to-one mapping relationship, the possibility of collision of multiple PUSCH opportunities with multiple Msg A PUSCHs in the NR system should be considered. For example, in order to reduce the possibility of collision of multiple Msg A PUSCHs, among the multiple Msg A PUSCH opportunities corresponding to the preamble, a modulo operation of the UE-ID based on the total number (M) of the multiple Msg A PUSCH opportunities is applied, and one Msg A PUSCH opportunity is determined, and the Msg A PUSCH may be transmitted through the one Msg A PUSCH opportunity. Here, the modulo operation is (UE-ID) mod (M), and each preamble is sequentially mapped to a PUSCH opportunity based on the result value of (UE-ID) mod (M) based on the UE-ID included in each preamble, and the UE can transmit Msg A PUSCH based on the mapped Msg A PUSCH opportunity. In this case, a window or timer for receiving Msg B can be started after one mapped PUSCH opportunity.

[0407] As another method of Msg A PUSCH transmission for the case where multiple PUSCH opportunities are mapped to one preamble, even if there is a possibility of collision between multiple Msg A PUSCHs, in order to increase the diversity and transmission probability of Msg A PUSCH, the UE can transmit Msg A PUSCH in all Msg A PUSCH opportunities corresponding to the preamble. In this case, the UE attempts to transmit Msg A PUSCH in multiple PUSCH opportunities corresponding to the preamble and performs LBT on all multiple PUSCH opportunities in the NR-U system. Therefore, it is necessary to configure which PUSCH opportunities among the multiple PUSCH opportunities will become the basis for starting the window or timer for receiving Msg B, and to this end, the following example can be used.

[0408] Here, similar to Examples 1 and 2, even if the UE succeeds in LBT, or regardless of whether LBT succeeds or fails, in the event of a situation where the channel state deteriorates, such as in the one PUSCH opportunity, the UE can estimate the detection error probability for the Msg A PUSCH for itself and can transmit only the Msg APRACH preamble without transmitting the Msg APUSCH. That is, among the following examples, those that can be utilized regardless of the success or failure of LBT are not limited to being applied to the NR-U system and can be applied to the licensed carrier.

[0409] (1) Example 3: Among multiple PUSCH opportunities, the last PUSCH opportunity that has successfully performed LBT After at least one symbol from the symbol, the timer starts from the first symbol configuration window or timer

[0410] Example 3 is a method in which a UE performs LBT on each of multiple PUSCH opportunities and configures a window or timer for receiving Msg B based on the PUSCH opportunity that succeeded in LBT. Example 3 is similar to Example 1 in that the window or timer for receiving Msg B is configured based on the PUSCH opportunity that succeeded in LBT. In the case of Example 3, when the UE fails LBT for all multiple PUSCHs, the window or timer for receiving Msg B is not configured. That is, when the UE fails to transmit Msg APUSCH, the window or timer for receiving Msg B is not started.

[0411] In Example 3, if LBT for a specific PUSCH opportunity is successful, Msg A PUSCH transmission in the corresponding PUSCH opportunity is performed normally, and a window or timer for receiving Msg B may also be started. Here, the start time of the window or timer for receiving Msg B may be at least one symbol after the last symbol of the PUSCH opportunity corresponding to the Msg A PRACH preamble transmitted by the UE. In other words, the window or timer for receiving Msg B may be configured to start at an interval of at least one symbol from the PUSCH opportunity in symbol units. In addition, provided that resources for monitoring Msg B are configured, the start time of the window or timer may be the first symbol of the resources for monitoring Msg B. Here, the resources for monitoring Msg B may be resources corresponding to the earliest CORESET of the Type 1-PDCCH common search space of the PDCCH configured for receiving Msg B.

[0412] Therefore, in the case where a UE that has sent a Msg A PRACH preamble succeeds in LBT and can then send a Msg APUSCH, the window or timer configured to receive Msg B may start from the first symbol of the resource used to monitor Msg B, and the corresponding start time may be a time point after at least one symbol from the last symbol of the Msg A PUSCH opportunity.

[0413] Figure 32 : is a diagram illustrating an example of configuring a window for receiving Msg B according to a PUSCH opportunity in which LBT has succeeded among a plurality of PUSCH opportunities. Figure 32In the embodiment, for multiple POs corresponding to the RO related to the Msg APRACH preamble transmitted by the UE, when the LBT for a specific PO fails, the UE does not configure a window or timer for receiving Msg B based on the specific PO. Instead, the UE performs LBT until a PO in which LBT succeeds occurs, transmits MsgA PUSCH in the PO in which LBT succeeds, and the window or timer for receiving Msg B can be configured at a time point after at least one symbol from the last symbol of the corresponding PO. Here, Figure 32 The shown PO corresponds to one Msg APRACH preamble in a one-to-many scheme and may be a resource redundantly allocated in the form of TDM.

[0414] (2) Example 4: Regardless of whether LBT succeeds or fails, the last PUSCH among multiple PUSCH opportunities The timing is at least one symbol after the last symbol of the timing, starting from the first symbol configuration window or timer start time

[0415] Example 4 is a method of always configuring a window or timer for receiving Msg B based on the last PUSCH opportunity among the multiple PUSCH opportunities corresponding to the Msg A PRACH preamble, regardless of whether LBT for each PUSCH opportunity succeeds or fails. That is, in order to prepare for LBT failure for all corresponding multiple PUSCH opportunities and to expect reception of a fallback RAR, the window or timer for receiving Msg B is always configured to start at least one symbol after the last symbol of the last PUSCH opportunity among the multiple TDM-controlled PUSCH opportunities. The method of Example 4 is applicable without distinguishing between licensed carriers and unlicensed carriers, and the operations of the UE and base station related to Example 4 may be the same as those described in Example 2.

[0416] In Example 4, if LBT for a specific Msg A PUSCH opportunity is successful, Msg A PUSCH transmission in the corresponding Msg APUSCH opportunity is performed normally, and a reception window or timer for Msg B may also be started based on the Msg APUSCH opportunity in which LBT is successful. In this case, the UE that transmits Msg A PUSCH can expect to receive a successful RAR and can expect to successfully complete the 2-step RACH procedure.

[0417] However, if LBT continues to fail for the last Msg A PUSCH opportunity, the window or timer for receiving Msg B is configured based on the last Msg A PUSCH opportunity regardless of whether LBT succeeds or fails. If the UE fails to send Msg A PUSCH even in the last Msg A PUSCH opportunity, the UE can expect to receive fallback RAR and can expect to send Msg 3 by falling back to the 4-step RACH procedure.

[0418] In this case, as described above, the time point at which the window or timer for receiving Msg B starts may be at least one symbol after the last symbol of the corresponding last Msg A PUSCH opportunity. In other words, the window or timer for receiving Msg B may be configured to start at an interval of at least one symbol from an Msg A PUSCH opportunity in symbol units. In addition, under the premise of configuring resources for monitoring Msg B, the start time of the window or timer may be the first symbol of the resources for monitoring Msg B. Here, the resources for monitoring Msg B may be resources corresponding to the earliest CORESET of the Type 1-PDCCH common search space of the PDCCH set for the UE to receive Msg B.

[0419] Figure 33 : is a diagram illustrating an example of configuring a window for receiving Msg B according to the last Msg A PUSCH opportunity regardless of success or failure of LBT among a plurality of Msg A PUSCH opportunities. Figure 33 In the embodiment, even if LBT fails for all three POs corresponding to the RO associated with the Msg A PRACH preamble transmitted by the UE, the window or timer for receiving Msg B may be configured based on the last PO. In particular, the UE may configure the window or timer for receiving Msg B at a time point at least one symbol after the last symbol of the corresponding last PO. Here, Figure 33 The shown PO corresponds to one Msg A PRACH preamble in a one-to-many scheme and may be a resource redundantly allocated in the form of TDM.

[0420] (3) Example 5: Regardless of whether LBT succeeds or fails, the first PUSCH opportunity among multiple PUSCH opportunities is Set the start time of the window or timer at least one symbol after the last symbol

[0421] In Example 5, for multiple Msg A PUSCH opportunities corresponding to the Msg A PUSCH preamble, regardless of whether LBT for each Msg A PUSCH opportunity is successful or failed. A window or timer for receiving Msg B is always set based on the first Msg A PUSCH opportunity among the multiple Msg A PUSCH opportunities. That is, the window or timer start time for receiving Msg B is set after at least one symbol from the last symbol of the first Msg A PUSCH opportunity among the multiple TDM-transferred Msg A PUSCH opportunities. Here, after the reception window or timer of Msg B based on the first Msg A PUSCH opportunity according to Example 5 is started, the operations of the UE and the base station can be the same as those described in Example 2, and at the same time, the UE can perform LBT on the multiple remaining Msg A PUSCH opportunities thereafter.

[0422] The UE configures a window or timer for receiving Msg B after the first Msg A PUSCH opportunity and expects to receive Msg B while performing LBT for subsequent Msg A PUSCH opportunities so that the reception time of Msg B may be before or after the transmission time of Msg APUSCH depending on which Msg A PUSCH opportunity the UE successfully transmits Msg A PUSCH. For example, if the UE successfully performs LBT for the first PUSCH opportunity and transmits Msg A PUSCH through the first Msg A PUSCH opportunity, the reception time of Msg B may be after the transmission time of Msg A PUSCH. However, if the UE fails to perform LBT for multiple Msg A PUSCH opportunities including the first Msg APUSCH opportunity and transmits Msg A PUSCH only in an Msg A PUSCH opportunity after the window or timer for Msg B reception expires, the reception time of Msg B may be before the transmission time of Msg A PUSCH.

[0423] Therefore, the subsequent operation of the UE that performs LBT for multiple Msg A PUSCH opportunities may vary as follows depending on whether the UE that performs LBT finally successfully performs LBT but receives Msg B at a time before sending Msg A PUSCH or receives Msg B at a time point after PUSCH transmission. Here, as described in Example 2, depending on whether the UE has sent Msg A PUSCH or the UE has not yet sent Msg_A PUSCH, the target object (such as a successful RAR or fallback RAR signal) that each UE expects to receive may be different. In addition, the problem of repeated transmission of successful RAR or fallback RAR can also be solved by applying a method similar to the method of Example 2.

[0424] First, when the UE receives Msg B from the base station before transmitting Msg A PUSCH, the base station receives the Msg AP RACH preamble and fails to receive Msg A PUSCH. Therefore, Msg B transmitted by the base station includes a fallback RAR containing information about fallback and Msg 3 transmission. Here, if the configured Msg A PUSCH opportunities still exist, the UE stores the fallback RAR and performs LBT for the remaining Msg A PUSCH opportunities in anticipation of Msg A PUSCH transmission. If the UE fails to perform LBT before the last Msg A PUSCH opportunity and cannot finally transmit Msg A PUSCH, the UE falls back to the 4-step RACH procedure using the information included in the previously received fallback RAR and transmits Msg 3. Here, considering the fact that the base station initially allocates multiple Msg A PUSCH opportunities, transmission information such as a grant for Msg 3 transmitted via the fallback RAR of Msg B can indicate subsequent resources.

[0425] On the other hand, if the UE receives Msg B from the base station after successfully performing LBT and transmitting Msg A PUSCH, the UE's subsequent operations vary depending on the content of Msg B transmitted by the base station. From the UE's perspective, since Msg A PUSCH has already been transmitted, if Msg B includes a fallback RAR, it can ignore the fallback RAR and can expect to receive a successful RAR. If no successful RAR is received during the reception window or timer period of Msg B, the UE can fall back to the 4-step RACH procedure based on the previously received fallback RAR and transmit Msg 3. Alternatively, if no successful RAR is received during the reception window or timer period of Msg B, the UE can perform a resource selection procedure for random access after a set backoff time to avoid conflict with redundantly transmitted RAPIDs.

[0426] Regarding the example described in the present disclosure, the UE may identify an operation after the configured window or timer for receiving Msg B has expired as an operation based on unsuccessful contention resolution. In this case, the UE may select the 2-step RACH procedure or the 4-step RACH procedure again according to the channel state after a pre-configured backoff time and perform a resource selection procedure for random access.

[0427] Although not limited thereto, the various descriptions, functions, processes, proposals, methods and / or operational flowcharts of the present disclosure disclosed in this document may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0428] In the following, a more detailed illustration will be given with reference to the accompanying drawings. In the following drawings / descriptions, unless otherwise specified, the same reference numerals may represent the same or corresponding hardware blocks, software blocks or functional blocks.

[0429] Figure 34 An example of a wireless communication environment to which embodiments of the present disclosure may be applied is shown.

[0430] Reference Figure 34 , the communication system 1 applied to the present disclosure includes: a wireless device, a base station, and a network. Here, the wireless device means a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and can be referred to as a communication / wireless / 5G device. Although not limited to this, the wireless device includes: a robot 100a, a vehicle 100b-1, 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, and an AI device / server 400. For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device includes an AR (augmented reality) / VR (virtual reality) / MR (mixed reality) device and can be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) set in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. Portable devices may include smartphones, smart tablets, wearable devices (e.g., smart watches, smart glasses), computers (e.g., laptop computers), etc. Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device 200a may operate as a base station / network node for other wireless devices.

[0431] Wireless devices 100a to 100f can be connected to a network 300 via a base station 200. Artificial intelligence (AI) technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can be connected to an AI server 400 via the network 300. The network 300 can be configured using a 3G network, a 4G network (e.g., LTE), or a 5G network (e.g., NR). Wireless devices 100a to 100f can communicate with each other via the base station 200 / network 300, but can also communicate directly without going through the base station / network (e.g., sidelink communication). For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0432] Wireless communications / connections 150a, 150b, and 150c can be performed between wireless devices 100a to 100f and base station 200, and between base station 200 and base station 200. Wireless communications / connections can be performed using various radio access technologies (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication), and inter-base station communication 150c. Through wireless communications / connections 150a, 150b, and 150c, wireless devices and base stations, wireless devices and base stations, and base stations and base stations can transmit and receive radio signals with each other. For example, wireless communications / connections 150a, 150b, and 150c can transmit and receive signals via various physical channels. To this end, based on various proposals of the present disclosure, at least a portion of various configuration information configuration processes, various signal processing procedures (e.g., channel coding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, and the like can be performed.

[0433] The above examples are those in which the elements and features of the present disclosure are combined in a predetermined form. Unless expressly provided otherwise, each component or function should be considered optional. Each component or feature can be implemented in a form not combined with other components or features. In addition, the examples of the present disclosure can also be configured by combining some elements and / or features. The order of operations described in the examples of the present disclosure can be changed. Some configurations or features of an embodiment example can be included in other examples, or can be replaced with corresponding configurations or features of other examples. Obviously, claims that are not clearly cited in the claims can be combined to form examples, or can be included as new claims by amendment after submission.

[0434] In some cases, specific operations described in this disclosure as being performed by a base station may be performed by a higher-layer node. That is, it is apparent that various operations performed in a network comprising multiple network nodes (including a base station) for communicating with a terminal may be performed by a base station or other network nodes other than a base station. Base station may be replaced by terms such as fixed station, gNodeB (gNB), Node B, eNodeB (eNB), access point, etc.

[0435] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the features of the present disclosure. Therefore, the description detailed above should not be interpreted as restrictive in all aspects, but rather as exemplary. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0436] Industrial Applicability

[0437] As described above, the method for receiving a downlink signal by a terminal based on a random access procedure in an unlicensed frequency band and the device therefor have been mainly described using an example applied to the fifth-generation NewRAT system, but can also be applied to various other wireless communication systems other than the fifth-generation NewRAT system.

Claims

1. A method performed by a terminal, the method comprising the following steps: Send message A to the base station; receiving a random access response RAR from the base station via message B; receiving, from the base station, information about at least one DRX timer configured for discontinuous reception (DRX) operation; as well as receiving a downlink signal from the base station during an on-duration based on the at least one DRX timer, The physical random access channel PRACH preamble is mapped to a valid physical uplink shared channel PUSCH opportunity for the message A. wherein, for both i) in response to sending only PRACH without PUSCH via message A and ii) in response to sending the PRACH and the PUSCH via message A, the window for detecting the message B starts at least one symbol after the last symbol of the PUSCH opportunity corresponding to the PRACH preamble transmission.

2. The method according to claim 1, in, The RAR is a fallback RAR, and the fallback RAR includes uplink UL grant information.

3. The method according to claim 2, in, transmitting a PUSCH scheduled by the UL grant information included in the fallback RAR, and Among them, a PDSCH for contention resolution is received.

4. The method according to claim 1, in, The window starts at the first symbol of the resource associated with the monitoring of message B.

5. A device comprising: at least one processor; as well as at least one memory operatively connected to the at least one processor and storing instructions for performing specific operations upon execution by the at least one processor, The specific operations include: Send message A; Receiving a random access response RAR via message B; receiving information about at least one DRX timer configured for discontinuous reception (DRX) operation; and receiving a downlink signal during an on-duration based on the at least one DRX timer, The physical random access channel PRACH preamble is mapped to a valid physical uplink shared channel PUSCH opportunity for the message A. wherein, for both i) in response to sending only PRACH without PUSCH via message A and ii) in response to sending the PRACH and the PUSCH via message A, the window for detecting the message B starts at least one symbol after the last symbol of the PUSCH opportunity corresponding to the PRACH preamble transmission.

6. A terminal, 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 storing instructions that, upon execution by the at least one processor, perform specific operations, The specific operations include: Send message A to the base station; receiving a random access response RAR from the base station via message B; receiving information about at least one DRX timer configured for discontinuous reception (DRX) operation from the base station; and receiving a downlink signal from the base station during an on-duration based on the at least one DRX timer, The physical random access channel PRACH preamble is a PRACH preamble mapped to a valid physical uplink shared channel PUSCH opportunity for the message A. wherein, for both i) in response to sending only PRACH without PUSCH via message A and ii) in response to sending the PRACH and the PUSCH via message A, the window for detecting the message B starts at least one symbol after the last symbol of the PUSCH opportunity corresponding to the PRACH preamble transmission.

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