Method and apparatus for performing a random access channel procedure in an unlicensed frequency band

Abstract

The present invention provides a method for a terminal to perform a random access channel procedure (RACH procedure) in an unlicensed frequency band. Specifically, the method may include: sending a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) to a base station; and receiving a contention resolution related message B from the base station in response to message A, wherein a power ramp counter is used to configure the transmission power of message A, and the power ramp counter has a value that increases based on a transmission spatial beam used for the transmission of message A being configured to be the same as a transmission spatial beam related to the transmission of a PRACH before message A.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for a user equipment to perform a random access procedure on an unlicensed frequency band, and more particularly, to a method and apparatus for setting a transmission power of a signal for the user equipment to perform a random access procedure. Background Art

[0002] As more and more communication devices require greater communication services with the development of the times, a next-generation system called the fifth generation (5G) is needed to provide improved wireless broadband communication relative to traditional LTE systems. In the 5G system, which is also referred to as New Radio Access Technology (NewRAT or NR), communication scenarios are classified into enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC).

[0003] eMBB is a next-generation mobile communication scenario characterized by high spectral efficiency, high user experience data rate, and high peak data rate. URLLC is a next-generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency, and ultra-high availability (e.g., vehicle-to-everything (V2X), emergency services, and remote control). mMTC is a next-generation mobile communication scenario characterized by low cost, low power consumption, short packets, and massive connectivity (e.g., Internet of Things (IoT)). Summary of the Invention

[0004] Technical Task

[0005] One technical task of the present disclosure is to provide a method and apparatus for a user equipment to perform a random access procedure on an unlicensed frequency band.

[0006] Additional aspects will be set forth in part in the following description, and in part will be obvious from the description, or may be learned by practice of the presented embodiments of the present disclosure.

[0007] Technical Solution

[0008] In one technical aspect of the present disclosure, there is provided a method for a user equipment to perform a random access channel (RACH) procedure on an unlicensed frequency band, the method including the steps of: transmitting a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) to a base station; and receiving a message B related to contention resolution from the base station in response to message A, wherein a power ramp counter can be used to configure a transmission power of message A, and wherein, based on a transmission spatial beam used for transmission of message A being configured to be the same as a transmission spatial beam related to transmission of a PRACH before message A, a value of the power ramp counter can be increased.

[0009] Based on the clear channel assessment (CCA) for Message A not failing, the value of the power ramp counter can be incremented.

[0010] The transmission of Message A can correspond to a retransmission of Message A.

[0011] The clear channel assessment (CCA) related to the Physical Random Access Channel (PRACH) may fail.

[0012] Based on the transmission spatial beam used for the transmission of Message A being configured differently from the transmission spatial beam related to the transmission of the PRACH before Message A, the value of the power ramp counter may not be incremented.

[0013] Based on the first PRACH and the first Physical Uplink Shared Channel (PUSCH) being sent together by Message A, the power ramp counter can be used to configure the transmission power.

[0014] In another technical aspect of the present disclosure, there is provided a user equipment for performing a Random Access Channel (RACH) procedure on an unlicensed frequency band, the user equipment including: at least one transceiver; at least one processor; and at least one memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to be capable of performing specific operations, the specific operations including: sending, to a base station, a Message A including a first Physical Random Access Channel (PRACH) and a first Physical Uplink Shared Channel (PUSCH); and receiving, in response to Message A from the base station, a Message B related to contention resolution, wherein the power ramp counter can be used to configure the transmission power of Message A, and wherein, based on the transmission spatial beam used for the transmission of Message A being configured to be the same as the transmission spatial beam related to the transmission of the PRACH before Message A, the value of the power ramp counter can be incremented.

[0015] Based on the clear channel assessment (CCA) for Message A not failing, the value of the power ramp counter can be incremented.

[0016] The transmission of Message A can correspond to a retransmission of Message A.

[0017] The clear channel assessment (CCA) related to the PRACH may fail.

[0018] Based on the transmission spatial beam used for the transmission of Message A being configured differently from the transmission spatial beam related to the transmission of the PRACH before Message A, the value of the power ramp counter may not be incremented.

[0019] Based on the first PRACH and the first PUSCH being sent together by Message A, the power ramp counter can be used to configure the transmission power.

[0020] In another technical aspect of the present disclosure, there is provided a device for performing a random access channel (RACH) procedure on an unlicensed frequency band. The device includes: at least one transceiver; at least one processor; and at least one memory, which is operatively connected to the at least one processor and stores instructions that, when executed, enable the at least one processor to perform specific operations. The specific operations include: sending, to a base station, a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH); and receiving, in response to message A from the base station, a message B related to contention resolution. Wherein, a power ramp counter can be used to configure the transmission power of message A, and wherein, based on the transmission spatial beam used for the transmission of message A being configured to be the same as the transmission spatial beam related to the transmission of the PRACH before message A, the value of the power ramp counter can be increased.

[0021] In another technical aspect of the present disclosure, there is provided a method for a base station to support a user equipment in a random access channel (RACH) procedure on an unlicensed frequency band. The method includes the steps of: receiving, from the user equipment, a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH); and sending, in response to message A to the user equipment, a message B related to contention resolution. Wherein, the transmission power of message A can be configured based on a power ramp counter, and wherein, based on the transmission spatial beam used for the transmission of message A being configured to be the same as the transmission spatial beam related to the transmission of the PRACH before message A, the value of the power ramp counter can be increased.

[0022] In another technical aspect of the present disclosure, there is provided a computer-readable storage medium storing at least one computer program including instructions that, when executed by at least one processor, enable the at least one processor to perform operations of a user equipment. The operations include: sending, to a base station, a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH); and receiving, in response to message A from the base station, a message B related to contention resolution. Wherein, a power ramp counter can be used to configure the transmission power of message A, and wherein, based on the transmission spatial beam used for the transmission of message A being configured to be the same as the transmission spatial beam related to the transmission of the PRACH before message A, the value of the power ramp counter can be increased.

[0023] Beneficial effects

[0024] According to the present disclosure, the transmission power of the signal for the user equipment to perform the random access procedure can be efficiently set.

[0025] The effects achievable through the embodiments of the present disclosure are not limited to those specifically described above, and those skilled in the art can derive other effects not described herein from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a diagram showing a control plane protocol stack and a user plane protocol stack in a radio interface protocol architecture conforming to the 3rd Generation Partnership Project (3GPP) radio access network standard between a user equipment (UE) and an evolved UMTS terrestrial radio access network (E-UTRAN).

[0027] Figure 2 is a diagram showing physical channels in a 3GPP system and a general signal transmission method using these physical channels.

[0028] Figures 3 to 5 is a diagram depicting channel transmission on an unlicensed frequency band.

[0029] Figure 6 is a diagram depicting an embodiment of a process for controlling uplink transmission power.

[0030] Figure 7 and Figure 8 is a diagram depicting an implementation example of operations of a user equipment and a base station according to an embodiment of the present disclosure.

[0031] Figure 9 is a diagram showing the basic processing of a two-step RACH.

[0032] Figure 10 is a diagram showing an embodiment of Msg A transmission according to the LBT success or failure of a user equipment and a transmission beam direction configuration.

[0033] Figure 11 is a diagram showing maintaining or increasing a power ramp counter according to a transmission direction of a user equipment according to an embodiment of the present disclosure.

[0034] Figure 12 is a diagram showing an operation flow of a two-step RACH process performed by a user equipment and a base station based on an embodiment of the present disclosure.

[0035] Figure 13 shows an example of a communication system to which an embodiment of the present disclosure is applied.

[0036] Figures 14 to 17 is a diagram showing various exemplary wireless devices to which an embodiment of the present disclosure is applicable. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The configurations, operations, and other features of the present disclosure will be readily understood from the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The following embodiments are examples in which the technical features of the present disclosure are applied to a 3rd Generation Partnership Project (3GPP) system.

[0038] Although the embodiments of the present disclosure are described in the context of Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), and New Radio Access Technology (NewRAT or NR) systems, they are merely examples. The embodiments of the present disclosure are applicable to any communication system corresponding to the above definitions.

[0039] In addition, the term "base station (BS)" as used herein covers "remote radio head (RRH)", "evolved Node B (eNode B or eNB)", "transmission point (TP)", "reception point (RP)", "repeater", etc.

[0040] The 3GPP communication standard defines a downlink (DL) physical channel corresponding to a resource element (RE) carrying information from a higher layer and a DL physical signal corresponding to an RE used in the physical (PHY) layer but not carrying information from a higher layer. For example, the DL physical channels include 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 automatic repeat request indicator channel (PHICH). The DL physical signals include, for example, reference signals (RS) and synchronization signals (SS). The RS, also known as a pilot, is a signal of a predefined special waveform known to both the next-generation Node B (gNB) and the user equipment (UE). For example, the RS includes cell-specific RS, UE-specific RS (UE-RS), positioning RS (PRS), and channel state information (CSI) RS (CSI-RS). The 3GPP LTE / LTE-A standard defines an uplink (UL) physical channel corresponding to an RE carrying information from a higher layer and a UL physical signal corresponding to an RE used in the PHY layer but not carrying information from a higher layer. For example, the UL physical channels include the physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), and physical random access channel (PRACH). The UL physical signals include the demodulation reference signal (DMRS) for UL control and data signals and the sounding reference signal (SRS) for UL channel measurement.

[0041] In the present disclosure, PDCCH, PCFICH, PHICH, and PDSCH respectively refer to a set of time-frequency resources or REs that carry downlink control information (DCI), control format indicator (CFI), DL acknowledgment / negative acknowledgment (ACK / NACK), and DL data. In addition, PUCCH, PUSCH, and PRACH respectively refer to a set of time-frequency resources or REs that carry uplink control information (UCI), UL data, and random access signals. In the present disclosure, specifically, the time-frequency resources or REs allocated to or belonging to PDCCH, PCFICH, PHICH, PDSCH, PUCCH, PUSCH, and PRACH are respectively referred to as PDCCH, PCFICH, PHICH, PDSCH, PUCCH, PUSCH, and PRACH resources or REs. When it is said that the UE transmits PUCCH, PUSCH, or PRACH, this means that the UE transmits UCI, UL data, or random access signals on or through PUSCH, PUCCH, or PRACH. In addition, when it is said that the gNB transmits PDCCH, PCFICH, PHICH, or PDSCH, this means that the gNB transmits DL data or DCI on or through PDCCH, PCFICH, PHICH, or PDSCH.

[0042] The OFDM symbols, carriers, subcarriers, and REs allocated to or configured with CRS, DMRS, CSI-RS, SRS, and UE-RS are respectively referred to as CRS, DMRS, CSI-RS, SRS, and UE-RS symbols, carriers, subcarriers, and REs. For example, the OFDM symbol allocated to or configured with the tracking reference signal (TRS) is referred to as the TRS symbol, the subcarrier allocated to or configured with the TRS is referred to as the TRS subcarrier, and the RE allocated to or configured with the TRS is referred to as the TRS RE. In addition, the subframe configured for TRS transmission is referred to as the TRS subframe. The subframe carrying the broadcast signal is referred to as the broadcast subframe or PBCH subframe, and the subframe carrying SS (e.g., the primary synchronization signal (PSS) and / or the secondary synchronization signal (SSS)) is referred to as the SS subframe or PSS / SSS subframe. The OFDM symbols, subcarriers, and REs allocated to or configured with PSS / SSS are respectively referred to as PSS / SSS symbols, subcarriers, and REs.

[0043] In the present disclosure, a CRS port, a UE-RS port, a CSI-RS port, and a TRS port are an antenna port configured for CRS transmission, an antenna port configured for UE-RS transmission, an antenna port configured for CSI-RS transmission, and an antenna port configured for TRS transmission, respectively. The antenna ports configured for CRS transmission can be distinguished from each other according to the positions of the REs occupied by the CRS through the CRS port. The antenna ports configured for UE-RS transmission can be distinguished from each other according to the positions of the REs occupied by the UE-RS through the UE-RS port. The antenna ports configured for CSI-RS transmission can be distinguished from each other according to the positions of the REs occupied by the CSI-RS through the CSI-RS port. Therefore, the terms CRS port, UE-RS port, CSI-RS port, and TRS port are used in the meaning of the patterns of the REs occupied by the CRS, UE-RS, CSI-RS, and TRS, respectively.

[0044] <Artificial Intelligence (AI)>

[0045] AI refers to the field of studying AI or its manufacturing methods, and machine learning refers to the field of defining various problems processed in the field of AI and studying methods for solving these various problems. Machine learning is defined as an algorithm that enhances the performance of a specific task through consistent experience with the task.

[0046] An artificial neural network (ANN) is a model used in machine learning and can mean the entire model of problem-solving ability composed of artificial neurons (nodes) that form a network through synaptic connections. An ANN can be defined by the connection pattern between neurons in different layers, the learning process for updating model parameters, and the activation function for generating output values.

[0047] An ANN can include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and an ANN can include synapses that link the neurons. In an ANN, each neuron can output the function value of the activation function for the input signal, weight, and bias input through the synapse.

[0048] Model parameters refer to the parameters determined through learning and include the weight values of synaptic connections and the biases of neurons. Hyperparameters mean the parameters to be set in a machine learning algorithm before learning and include the learning rate, the number of repetitions, the mini-batch size, and the initialization function.

[0049] The learning objective of an ANN can be to determine the model parameters that minimize the loss function. In the learning process of an ANN, the loss function can be used as an index for determining the optimal model parameters.

[0050] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning according to the learning mechanism.

[0051] Supervised learning may refer to a method of training an ANN in a state where labels of learning data are given, and the labels may mean the correct answers (or result values) that the ANN must infer when the learning data is input to the ANN. Unsupervised learning may refer to a method of training an ANN in a state where labels of learning data are not given. Reinforcement learning may refer to a method of learning an agent defined in a specific environment to select behaviors or sequences of behaviors that maximize the cumulative reward in each state.

[0052] Machine learning implemented with a deep neural network (DNN) including multiple hidden layers between ANNs is called deep learning. Deep operation is a part of machine operation. Machine learning used in this article includes deep operation.

[0053] <Robot>

[0054] A robot may refer to a machine that automatically processes or operates a given task based on its own capabilities. Specifically, a robot with the functions of recognizing the environment and making self-determinations may be called an intelligent robot.

[0055] Robots can be classified into industrial robots, medical robots, household robots, military robots, etc. according to the purpose of use or field.

[0056] A robot may include a drive unit having an actuator or a motor and perform various physical operations such as moving the robot joints. In addition, a mobile robot may include a drive unit having wheels, brakes, thrusters, etc., and may travel on the ground or fly in the air through the drive unit.

[0057] <Autonomous driving (self-driving)>

[0058] Autonomous driving refers to the technology of driving by itself. An autonomous driving vehicle refers to a vehicle that moves without user manipulation or with minimal user manipulation.

[0059] For example, autonomous driving may include technologies for maintaining the current lane, for automatically adjusting the speed (e.g., adaptive cruise control), for automatically moving along a predetermined route, and for automatically setting a route and driving along the route when determining a destination.

[0060] Vehicles may include vehicles having only an internal combustion engine, hybrid vehicles having both an internal combustion engine and an electric motor, and electric vehicles having only an electric motor. In addition, vehicles may include not only automobiles but also trains, motorcycles, etc.

[0061] An autonomous driving vehicle may be regarded as a robot having an autonomous driving function.

[0062] <Extended reality (XR)>

[0063] Extended reality is collectively referred to as virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology provides real-world objects and backgrounds as CG images. AR technology provides virtual CG images on real object images. MR technology is a computer graphics technology that mixes and combines virtual objects with the real world.

[0064] MR technology is similar to AR technology in that real objects and virtual objects are shown together. However, MR technology is different from AR technology in that AR technology uses virtual objects to supplement real objects, while MR technology treats virtual objects and real objects in the same way.

[0065] XR technology can be applied to head-mounted displays (HMDs), head-up displays (HUDs), mobile phones, tablet PCs, laptops, desktop computers, TVs, digital signage, etc. Devices applying XR technology can be called XR devices.

[0066] 5G communication related to the new radio access technology (NR) system will be described below.

[0067] The three key requirement areas of 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine-type communication (mMTC), and (3) ultra-reliable low-latency communication (URLLC).

[0068] Some use cases may require multiple dimensions for optimization, while other use cases may focus only on one key performance indicator (KPI). 5G supports these different use cases in a flexible and reliable manner.

[0069] eMBB far exceeds basic mobile Internet access and encompasses rich interactive work, media, and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers of 5G, and in the 5G era, for the first time, we can see the absence of dedicated voice services. In 5G, simply using the data connection provided by the communication system, voice is expected to be processed as an application. The main drivers of increased traffic are the size of the content and the increase in the number of applications that require high data rates. As more devices are connected to the Internet, streaming services (audio and video), interactive video, and mobile Internet connections will continue to be used more widely. Many of these applications require always-on connections to push real-time information and notifications to users. For the mobile communication platform, cloud storage and applications are increasing rapidly. This applies to both work and entertainment. Cloud storage is a specific use case that drives the growth of uplink data rates. 5G will also be used for remote work in the cloud, which, when implemented with a haptic interface, requires much lower end-to-end latency to maintain a good user experience. Entertainment (e.g., cloud gaming and video streaming) is another key driver of the demand for increased mobile broadband capacity. Entertainment on smartphones and tablets anywhere will be very important, including in highly mobile environments (e.g., trains, cars, and airplanes). Another use case is AR for entertainment and information search, which requires very low latency and a large amount of instant data volume.

[0070] One of the most anticipated 5G use cases is the ability to actively connect embedded sensors in various fields, i.e., mMTC. It is expected that by 2020, there will be 20.4 billion potential Internet of Things (IoT) devices. In industrial IoT, 5G is one of the key areas that play a crucial role in realizing smart cities, asset tracking, smart utilities, agriculture, and security infrastructure.

[0071] URLLC includes services that will transform industries with ultra-reliable / available, low-latency links (e.g., remote control of critical infrastructure and self-driving vehicles). The reliability level and latency are crucial for smart grid control, industrial automation, robotics, drone control and coordination, etc.

[0072] Now, multiple use cases in the 5G communication system including the NR system will be described in detail.

[0073] As a means of providing streams at data rates ranging from several hundred megabits per second to several gigabits per second, 5G can complement fiber to the home (FTTH) and cable broadband (or Data Over Cable Service Interface Specification (DOCSIS)). TV broadcasts with a resolution of 4K or above (6K, 8K, and higher), as well as virtual reality (VR) and augmented reality (AR), require such high speeds. VR applications and AR applications mainly include immersive sports games. Specific applications may require special network configurations. For example, for VR games, game companies may have to integrate the core server with the edge network server of the network operator to minimize latency.

[0074] The automotive industry is expected to become a very important new driver of 5G, with many use cases for mobile communications in vehicles. For example, passengers' entertainment requires mobile broadband with both high capacity and high mobility, as future users expect to continue their good-quality connections regardless of their location and speed. Other use cases in the automotive industry are AR dashboards. These display overlay information on top of what the driver sees through the front window, thus identifying objects in the dark and telling the driver the distance and movement of these objects. In the future, wireless modules will allow communication between vehicles themselves, between vehicles and supporting infrastructure, and between vehicles and other connected devices (such as those carried by pedestrians). Safety systems can guide drivers on alternative courses of action to allow them to drive more safely and reduce the risk of accidents. The next stage will be remotely controlled or self-driving vehicles. These require very reliable and very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will perform all driving activities, while the driver focuses on traffic anomalies that the vehicle itself cannot explain. The technical requirements for self-driving vehicles require ultra-low latency and ultra-high reliability, raising traffic safety to a level that humans cannot achieve.

[0075] Smart cities and smart homes (often referred to as the smart society) will be embedded with dense wireless sensor networks. A distributed network of smart sensors will identify the conditions for cost-effective and energy-efficient maintenance of a city or a home. Similar setups can be made for individual homes, where temperature sensors, window and heating controllers, burglar alarms, and household appliances are all wirelessly connected. Many of these sensors typically have the characteristics of low data rate, low power, and low cost, but for example, real-time high-definition (HD) video may be required in some types of monitoring devices.

[0076] The consumption and distribution of energy, including heat or gas, are becoming highly decentralized, thus requiring the automated control of very distributed sensor networks. The smart grid interconnects these sensors and uses digital information and communication technologies to collect information and take actions. This information can include information on the behavior of suppliers and consumers, thus allowing the smart grid to improve the efficiency, reliability, economy, and sustainability of the production and distribution of fuel (e.g., electricity) in an automated manner. The smart grid can be regarded as another sensor network with low latency.

[0077] There are many applications in the health sector that can benefit from mobile communication. Communication systems allow for telemedicine, which provides clinical care over long distances. It helps to eliminate distance barriers and can improve access to medical services that are often not continuously available in remote rural communities. It is also used to save lives in emergency care and emergencies. Wireless sensor networks based on mobile communication can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0078] For industrial applications, wireless communication and mobile communication are becoming increasingly important. The installation and maintenance of wires are expensive, and for many industries, the possibility of replacing cables with reconfigurable wireless links is an attractive opportunity. However, achieving this requires the wireless connection to work with similar latency, reliability, and capacity as cables and its management to be simplified. Low latency and a very low error probability are new requirements that 5G needs to address.

[0079] Finally, logistics and freight tracking are important use cases of mobile communication, which allows the use of location-based information systems to track inventory and packages wherever they are. Logistics and freight tracking use cases generally require lower data rates, but require large coverage and reliable location information.

[0080] Figure 1 Shows the control plane protocol stack and the user plane protocol stack in the radio interface protocol that complies with the 3GPP radio access network standard between the UE and the evolved UMTS terrestrial radio access network (E-UTRAN). The control plane is the path for the UE and the E-UTRAN to send control messages to manage calls, and the user plane is the path for sending data generated from the application layer (e.g., voice data or Internet packet data).

[0081] The physical (PHY) layer at layer 1 (L1) provides an information transfer service to its higher layer, the medium access control (MAC) layer. The PHY layer is connected to the MAC layer via a transport channel. The transport channel transfers data between the MAC layer and the PHY layer. Data is transmitted on a physical channel between the PHY layers of the transmitter and the receiver. The physical channel uses time and frequency as radio resources. Specifically, the physical channel is modulated according to orthogonal frequency division multiple access (OFDMA) for the downlink (DL), and according to single carrier frequency division multiple access (SC-FDMA) for the uplink (UL).

[0082] The MAC layer at layer 2 (L2) provides services to its higher layer, the radio link control (RLC) layer, via logical channels. The RLC layer at L2 supports reliable data transfer. The RLC function can be implemented in the functional blocks of the MAC layer. The packet data convergence protocol (PDCP) layer at L2 performs header compression to reduce the amount of unnecessary control information, and thus efficiently transmits Internet protocol (IP) packets (such as IP version 4 (IPv4) or IP version 6 (IPv6) packets) via an air interface with a narrow bandwidth.

[0083] The radio resource control (RRC) layer at the lowest part of layer 3 (or L3) is only defined on the control plane. The RRC layer controls logical channels, transport channels, and physical channels related to the configuration, reconfiguration, and release of radio bearers. A radio bearer refers to the service provided at L2 for data transfer between the UE and the E-UTRAN. For this purpose, the RRC layers of the UE and the E-UTRAN exchange RRC messages with each other. If an RRC connection is established between the UE and the E-UTRAN, the UE is in the RRC connected mode; otherwise, the UE is in the RRC idle mode. The non-access stratum (NAS) layer above the RRC layer performs functions including session management and mobility management.

[0084] The DL transport channels for transferring data from the E-UTRAN to the UE include the broadcast channel (BCH) carrying system information, the paging channel (PCH) carrying paging messages, and the shared channel (SCH) carrying user traffic or control messages. DL multicast traffic or control messages or DL broadcast traffic or control messages can be transmitted on the DL SCH or a separately defined DL multicast channel (MCH). The UL transport channels for transferring data from the UE to the E-UTRAN include the random access channel (RACH) carrying initial control messages and the UL SCH carrying user traffic or control messages. The logical channels defined above the transport channels and mapped to the transport channels include the broadcast control channel (BCCH), the paging control channel (PCCH), the common control channel (CCCH), the multicast control channel (MCCH), the multicast traffic channel (MTCH), etc.

[0085] Figure 2 Illustrate the physical channels in the 3GPP system and the general method of transmitting signals on these physical channels.

[0086] Refer to Figure 2 , when the UE is powered on or enters a new cell, the UE performs initial cell search (S201). The initial cell search involves obtaining synchronization with the eNB. Specifically, by receiving the Primary Synchronization Channel (P-SCH) and the Secondary Synchronization Channel (S-SCH) from the eNB, the UE synchronizes its timing to the eNB and obtains the cell identifier (ID) and other information. Then, the UE can obtain the information broadcast in the cell by receiving the Physical Broadcast Channel (PBCH) from the eNB. During the initial cell search, the UE can monitor the DL channel status by receiving the Downlink Reference Signal (DLRS).

[0087] After the initial cell search, the UE can obtain detailed system information (S202) by receiving the Physical Downlink Control Channel (PDCCH) and receiving the Physical Downlink Shared Channel (PDSCH) based on the information included in the PDCCH.

[0088] If the UE initially accesses the eNB or does not have radio resources for signal transmission to the eNB, the UE can perform a random access procedure with the eNB (S203 to S206). During the random access procedure, the UE can send a predetermined sequence as a preamble on the Physical Random Access Channel (PRACH) (S203 and S205), and can receive a response message for the preamble on the PDCCH and the PDSCH associated with the PDCCH (S204 and S206). In the case of contention-based RACH, the UE can additionally perform a contention resolution procedure.

[0089] After the above process, the UE can receive the PDCCH and / or PDSCH from the eNB (S207), and send the Physical Uplink Shared Channel (PUSCH) and / or the Physical Uplink Control Channel (PUCCH) to the eNB (S208), which is a general DL and UL signal transmission process. Specifically, the UE receives Downlink Control Information (DCI) on the PDCCH. Here, the DCI includes control information (e.g., resource allocation information for the UE). Different DCI formats are defined according to different uses of the DCI.

[0090] The control information sent by the UE on the UL to the eNB or received from the eNB on the DL includes DL / UL acknowledgement / negative acknowledgement (ACK / NACK) signals, channel quality indicator (CQI), precoding matrix index (PMI), rank indicator (RI), etc. In the 3GPP LTE system, the UE can send control information (e.g., CQI, PMI, RI, etc.) on the PUSCH and / or PUCCH.

[0091] In the NR system, it is being considered to use ultra-high frequency bands (i.e., millimeter frequency bands of 6 GHz or above) to send data in a wide frequency band while maintaining high transmission rates for multiple users. 3GPP refers to this system as NR. In this disclosure, this system will also be referred to as the NR system.

[0092] In NR, various parameter sets or subcarrier spacings (SCS) can be supported to support various 5G services. For example, for an SCS of 15 kHz, a wide area in the traditional cellular band can be supported, while for an SCS of 30 kHz or 60 kHz, dense urban areas, low latency, and wide carrier bandwidths can be supported. For an SCS of 60 kHz or higher, a bandwidth greater than 24.25 kHz can be supported to overcome phase noise.

[0093] The NR frequency band can be defined by two types of frequency ranges, FR1 and FR2. FR1 can be the Sub-6 GHz range, and FR2 can be the range above 6 GHz called millimeter wave (mmW).

[0094] Table 1 below defines the NR frequency band.

[0095] [Table 1]

[0096] Frequency range designation Corresponding frequency range Subcarrier spacing (SCS) FR1 410 MHz–7125 MHz 15, 30, 60 kHz FR2 24250 MHz - 52600 MHz 60, 120, 240 kHz

[0097] <License-Free Band / Shared Spectrum System>

[0098] Figure 3 is a diagram showing an exemplary wireless communication system supporting a license-free band to which various embodiments of the present disclosure are applicable.

[0099] In the following description, a cell operating in an authorized band (hereinafter referred to as the L band) is defined as an L cell, and the carrier of the L cell is defined as (DL / UL) LCC. In addition, a cell operating in a license-free band (hereinafter referred to as the U band) is defined as a U cell, and the carrier of the U cell is defined as (DL / UL) UCC. The carrier / carrier frequency of a cell can refer to the operating frequency of the cell (e.g., the center frequency). Cells / carriers (e.g., component carriers (CCs)) are collectively referred to as cells.

[0100] As Figure 3As shown in (a) of FIG. , when the UE and the BS transmit and receive signals in the LCC and UCC of carrier aggregation, the LCC can be configured as the primary CC (PCC), and the UCC can be configured as the secondary CC (SCC).

[0101] As Figure 3 As shown in (b) of FIG. , the UE and the BS can transmit and receive signals in one UCC or multiple carrier-aggregated LCCs and UCCs. That is, the UE and the BS can transmit and receive signals only in the UCC without an LCC. The operations of transmitting and receiving signals in the unlicensed frequency band described in various embodiments of the present disclosure can be performed based on all the above deployment scenarios (unless otherwise specified).

[0102] 1. Radio frame structure for unlicensed bands

[0103] LTE frame structure type 3 or NR frame structure can be used for operations in the unlicensed frequency band. The configuration of the OFDM symbols occupied by UL / DL signal transmission in the frame structure for the unlicensed frequency band can be configured by the BS. Herein, the OFDM symbols can be replaced by SC-FDM(A) symbols.

[0104] For DL signal transmission in the unlicensed frequency band, the BS can indicate to the UE via signaling the configuration of the OFDM symbols used in subframe #n. In the following description, the subframe can be replaced by a time slot or a TU.

[0105] Specifically, in a wireless communication system supporting the unlicensed frequency band, the UE can assume (or identify) the configuration of the OFDM symbols occupied by a specific field in DCI received from the BS in subframe #n-1 or subframe #n (e.g., the configuration field of the LAA subframe).

[0106] Table 2 shows an exemplary method of indicating the configuration of the OFDM symbols used for transmitting DL physical channels and / or physical signals in the current and / or next subframe through the LAA subframe configuration field in a wireless communication system.

[0107] [Table 2]

[0108]

[0109] For UL signal transmission in the unlicensed frequency band, the BS can send information about the UL transmission period to the UE via signaling.

[0110] Specifically, in an LTE system supporting the unlicensed frequency band, the UE can obtain the “UL duration” and “UL offset” information of subframe #n from the “UL duration and offset” field in the detected DCI.

[0111] Table 3 shows an exemplary method of indicating UL offset and UL duration configuration through UL duration and offset fields in a wireless communication system.

[0112] [Table 3]

[0113]

[0114] 2. Overview of the channel access procedure

[0115] Unless otherwise indicated, the following definitions apply to the terms used in the following description of various embodiments of the present disclosure.

[0116] - A channel refers to a carrier or a part of a carrier that includes a set of consecutive RBs that perform a channel access procedure in a shared spectrum.

[0117] - A channel access procedure can be a sensing-based procedure that evaluates the availability of a channel for performing a transmission. The basic unit of sensing is a sensing time slot with a duration of T sl = 9 us. If the BS or UE senses the channel during the sensing time slot duration and determines that the power detected within at least 4 us during the sensing time slot duration is less than the energy detection threshold X Thresh , then the sensing time slot duration can be considered idle. Otherwise, the sensing time slot duration T sl can be considered busy.

[0118] - Channel occupancy refers to the transmission on a channel from the BS / UE after performing the corresponding channel access procedure in this subclause.

[0119] - Channel occupancy time refers to the total time that the BS / UE and any BS / UE sharing the channel occupancy perform transmissions on the channel after the BS / UE performs the corresponding channel access procedure described in this subclause. To determine the channel occupancy time, if the transmission gap is less than or equal to 25 us, the gap duration can be included in the channel occupancy time. The channel occupancy time can be shared for transmissions between the BS and the corresponding UE.

[0120] 3. Downlink channel access procedure

[0121] For DL signal transmission in an unlicensed band, the BS can perform a DL channel access procedure (CAP) for the unlicensed band as follows.

[0122] 3.1. Type 1 DL channel access procedure

[0123] This subclause describes the CAP to be performed by the BS, where the duration spanned by the sensing time slots sensed as idle before DL transmission is random. This subclause applies to the following transmissions:

[0124] - Transmissions initiated by the BS, including PDSCH / PDCCH / EPDCCH, or

[0125] - Transmissions initiated by the BS, including unicast PDSCH with user plane data or unicast PDSCH with user plane data and unicast PDCCH scheduling user plane data, or

[0126] - Transmissions initiated by the BS, having only discovery bursts or discovery bursts multiplexed with non-unicast information, where the duration of the transmission is greater than 1 ms or the transmission results in a discovery burst duty cycle exceeding 1 / 20.

[0127] The BS can sense whether the channel is idle during the sensing slot period with a postponement duration Td and perform the transmission after the counter N becomes 0 in the subsequent step 4. In this case, the counter N is adjusted for the additional sensing slot duration through channel sensing according to the following procedure.

[0128] 1) Set N = Ninit. Here, Ninit is a random number uniformly distributed between 0 and CWp. Then, move to step 4.

[0129] 2) If N > 0 and the BS selects to decrease the counter, set N = N - 1.

[0130] 3) Sense the channel during the additional sensing slot duration. In this case, when the additional sensing slot duration is idle, move to step 4. If not, move to step 5.

[0131] 4) If N = 0, stop the corresponding process. Otherwise, move to step 2.

[0132] 5) Sense the channel if a busy sensing slot in the additional postponement duration Td is detected or all sensing slots in the additional postponement duration Td are detected as idle until.

[0133] 6) If the corresponding channel is sensed as idle during all sensing slot durations of the additional postponement duration Td, move to step 4. Otherwise, move to step 5.

[0134] Figure 4 It is a diagram showing the DL CAP for transmission in an unlicensed band to which various embodiments of the present disclosure are applicable.

[0135] The type 1 DL CAP for transmission in an unlicensed band to which various embodiments of the present disclosure are applicable can be summarized as follows.

[0136] For DL transmission, a transmission node (e.g., BS) can initiate the CAP (2010).

[0137] The BS can randomly select a backoff counter N within the contention window (CW) according to step 1. N is set to an initial value N init (2020). N init is a random value selected between 0 and CW p .

[0138] Subsequently, when the backoff counter value N is 0 (2030; yes) according to step 4, the BS terminates the CAP (2032). Then, the BS can perform a transmission (Tx) burst (2034). Conversely, when the backoff counter value N is not 0 (2030; no), the BS decrements the backoff counter value by 1 according to step 2 (2040).

[0139] Subsequently, the BS checks whether the channel is idle (2050). If the channel is idle (2050; yes), the BS determines whether the backoff counter value is 0 (2030).

[0140] Conversely, when the channel is not idle, i.e., the channel is busy in operation 2050 (2050; no), the BS determines whether the channel is idle during a postponement duration T longer than the sensing slot duration (e.g., 9 us) d (25 us or longer) (2060). If the channel is idle during the postponement duration (2070; yes), the BS can resume the CAP.

[0141] For example, when the backoff counter value N init is 10 and the channel is determined to be idle after the backoff counter value is decremented to 5, the BS senses the channel during the postponement duration and determines whether the channel is idle. If the channel is idle during the postponement duration, the BS can resume the CAP from the backoff counter value 5 (or from the backoff counter value 4 obtained by decrementing the backoff counter value 5 by 1), rather than setting the backoff counter value N init .

[0142] On the other hand, when the channel is busy during the postponement duration (2070; no), the BS determines again whether the channel is idle during a new postponement duration by performing step 2060 again.

[0143] If the BS has not performed a transmission after step 4 in the above process, the BS can perform a transmission on the channel if the following conditions are met:

[0144] If the BS is ready to send and the channel has been sensed idle for at least the sensing slot duration T sl and if the channel has been sensed idle for all sensing slot durations of the postponement duration T d immediately preceding this transmission.

[0145] Conversely, if the channel is not sensed as idle when the BS first senses the channel after it is ready to transmit during the sensing slot duration T sl or if the channel is not sensed as idle during any sensing slot duration of the deferral duration T d immediately preceding this expected transmission, then the BS proceeds to step 1 after sensing the channel idle during the sensing slot duration of the deferral duration T sl .

[0146] The deferral duration T d includes a duration T p equal to m f consecutive sensing slot durations (=16 us). Each sensing slot duration T sl is 9 us and the duration T f includes an idle sensing slot duration T f at the start of the duration T sl .

[0147] Table 4 shows that mp, minimum CW, maximum CW, maximum channel occupancy time (MCOT), and the allowed CW size applied to the CAP vary according to the channel access priority class.

[0148] [Table 4]

[0149]

[0150] 3.2. Type 2 DL channel access procedure

[0151] 3.2.1. Type 2A DL channel access procedure

[0152] The BS can perform a DL transmission immediately after sensing the corresponding channel idle for at least a sensing duration T short dl (=25 us). T short dl includes a duration T f (=16 us) after one sensing slot duration. T f includes a sensing slot at the start of T f . If two sensing slots within T short dl are sensed as idle, the channel is considered idle within T short dl .

[0153] 3.2.2. Type 2B DL channel access procedure

[0154] The BS can perform a transmission immediately after the channel is sensed idle during Tf = 16 μs. Tf includes a sensing time slot that occurs within the last 9 μs of Tf. The channel is considered idle during Tf when the channel is sensed to be in the idle state for at least a total of 5 μs or longer and for at least 4 μs of the sensing that occurs during the sensing time slot.

[0155] 3.2.3. Type 2C DL channel access procedure

[0156] When the BS follows the procedures in this section to perform a transmission, the BS does not sense the channel before performing the transmission. The duration corresponding to the transmission is at most 584 μs.

[0157] 4.1. Channel access procedure for transmission on multiple channels

[0158] The BS can access multiple channels for performing a transmission in one of the following Type A and Type B procedures.

[0159] 4.1. Type A multi-carrier access procedure

[0160] According to the procedures described in this subclause, the BS performs channel access on each channel c i ∈ C, where C is the set of channels that the BS intends to transmit on, i = 0, 1,... q - 1, and q is the number of channels that the BS is going to transmit on.

[0161] For each channel c i determine the counter N considered in the CAP, and in this case, the counter for each channel is denoted as

[0162] 4.1.1. Type A1 multi-carrier access procedure

[0163] For each channel c i independently determine the counter N considered in the CAP, and the counter for each channel is denoted as

[0164] In the case where the BS stops the transmission on a channel c j ∈ C, if it can be guaranteed long - term that there are no other technologies sharing the channel (e.g., according to regulations), then when for each channel ci (where ci is different from cj (c i ≠ c j )) and an idle time slot is detected after a waiting duration of 4·T sl or re - initialization then the BS can resume decrease.

[0165] 4.1.2. Type A2 multi-carrier access procedure

[0166] Each channel cj The counter N ∈ C can be determined according to Subclause 1.8.3 above and is represented by . Here, c j can mean the channel with the maximum CWp value. For each channel c j ,

[0167] When the BS stops transmission on any of the determined channels, the BS re-initializes for all channels

[0168] 4.2. Type B multi-channel access procedure

[0169] The BS can select the channel c j ∈ C as follows.

[0170] - The BS randomly selects c uniformly from C before each transmission on multiple channels c i ∈ C j .

[0171] - Or the BS does not select c j more than once per second.

[0172] In this document, C is the set of channels that the BS intends to transmit on, i = 0, 1,... q - 1, and q is the number of channels that the BS is to transmit on.

[0173] For transmission on channel c j , the BS performs channel access on channel c j according to the procedure described in Subclause 1.8.3.1 and the modifications described in Subclause 1.8.4.2.1 or Subclause 1.8.4.2.2.

[0174] For transmission on the channel c i ∈ C among the channels c i ≠ c j ,

[0175] For each channel c i , the BS senses channel c i at least within the sensing interval T mc = 25 us immediately before transmission on channel c i . The BS can perform transmission on channel c mc immediately after sensing that channel c i is idle during at least the sensing interval T i . When the channel is sensed as idle during all time periods when idle sensing of channel c mc is performed within a given interval T j , channel c i can be considered to be idle at Tmc Idle internally.

[0176] The BS does not transmit continuously on channel c mcot,p for a period exceeding T as given in Table 15. i ≠c j (c i ∈ C). T is determined using the channel access parameters for channel c. mcot,p Use the channel access parameters for channel c j to determine.

[0177] During the course of this subclause, the channel frequencies of the channel set C selected by the gNB are a subset of a predefined set of channel frequencies.

[0178] 4.2.1. Type B1 multi-channel access procedure

[0179] Maintain a single CWp value for the channel set C.

[0180] To determine CWp for channel access on channel c j the steps in the procedure described in Subclause 1.8.3.1 are modified as follows.

[0181] - If at least 80% (Z = 80%) of the HARQ-ACK values corresponding to PDSCH transmissions in the reference subframe k for all channels c i ∈ C are determined to be NACK, CWp for all priority classes p ∈ {1, 2, 3, 4} is increased to the next highest allowed value. Otherwise, the procedure goes to step 1.

[0182] 4.2.2. Type B2 multi-channel access procedure

[0183] Maintain the CWp value independently for each channel c i ∈ C. To determine Ninit for channel c j use the CWp value of channel c j1 ∈ C. Here, c j1 is the channel among all channels in the set C that has the maximum CWp.

[0184] 5. Uplink channel access procedure

[0185] The UE and the BS that schedules UL transmissions for the UE perform the following procedure to access the channel (on which LAA SCell transmission is performed). Assume that the UE and the BS are substantially configured with a PCell as an authorized band and one or more SCells as an unlicensed band. The UL CAP operation applicable to this disclosure will be described in detail below, where the unlicensed band is denoted as LAA SCell. Even when only the unlicensed band is configured for the UE and the BS, the UL CAP operation can be applied in the same manner.

[0186] The UE can perform UL transmission according to the channel accessed by Type 1 or Type 2 UL CAP.

[0187] Table 5 shows that mp, minimum CW, maximum CW, MCOT, and allowed CW size applied to CAP vary according to the channel access priority class.

[0188] [Table 5]

[0189]

[0190] 5.1. Type 1 UL channel access procedure

[0191] This subclause describes the CAP performed by the UE, where the duration spanned by the sensing time slots sensed as idle before UL transmission is random. This subclause applies to the following transmissions:

[0192] - PUSCH / SRS transmissions scheduled and / or configured by the BS

[0193] - PUCCH transmissions scheduled and / or configured by the BS

[0194] - Transmissions related to the random access procedure (RAP)

[0195] Figure 5 It is a diagram showing the UL CAP for transmissions in the unlicensed band to which various embodiments of the present disclosure are applicable.

[0196] Type 1 UL CAP for transmissions in the unlicensed band to which various embodiments of the present disclosure are applicable can be summarized as follows.

[0197] For UL transmission, a transmission node (e.g., UE) can initiate CAP to operate in the unlicensed band (2110).

[0198] The UE can randomly select a backoff counter N within the CW according to step 1. N is set to the initial value N init (2120). N init is a value randomly selected between 0 and CW p inclusive.

[0199] Subsequently, when according to step 4, the backoff counter value N is 0 (2130; yes), the UE ends the CAP (2132). The UE can then send a Tx burst (2134). On the other hand, if the backoff counter value is not 0 (2130; no), the UE decrements the backoff counter value by 1 according to step 2 (2140).

[0200] Subsequently, the UE checks whether the channel is idle (2150). If the channel is idle (2150; yes), the UE checks whether the backoff counter value is 0 (2130).

[0201] Conversely, if the channel is not idle, i.e., the channel is busy (2150; No), the UE checks whether the channel is idle (2160) according to step 5 during a deferral duration T that is longer than the slot duration (e.g., 9 us). If the channel becomes idle within the deferral duration (2170; Yes), the UE may resume the CAP. d (25 us or longer). If the channel becomes idle within the deferral duration, the UE may resume the CAP.

[0202] For example, if the backoff counter value N init is 10 and the channel is determined to be idle after the backoff counter value is decremented to 5, the UE senses the channel during the deferral duration and determines whether the channel is idle. If the channel is idle during the deferral duration, the UE may perform the CAP again from the backoff counter value 5 (or the backoff counter value 4 after decrementing the backoff counter value by 1), rather than setting the backoff counter value N init .

[0203] On the other hand, if the channel is busy during the deferral duration (2170; No), the UE checks again whether the channel is idle during a new deferral duration by performing operation 2160 again.

[0204] If the UE has not yet performed a UL transmission on the channel for UL transmission after step 4 in the above process, the UE may perform a UL transmission on the channel if the following conditions are met.

[0205] - If the UE is ready to perform the transmission and the channel is sensed as idle for at least the sensing slot duration Tsl, and

[0206] - If the channel has been sensed as idle for all slot durations of the deferral duration T d immediately before the transmission.

[0207] Conversely, if the channel has not been sensed as idle during the sensing slot duration T sl when the UE first senses the channel after being ready to send, or if the channel has not been sensed as idle during any sensing slot duration of the deferral duration T d immediately before the expected transmission, then after the channel is sensed as idle during the slot duration of the deferral duration T d , the UE proceeds to step 1.

[0208] The deferral duration T d includes a duration T p that follows m f (= 16 us) consecutive slot durations, where each slot duration T sl is 9 us, and Tf including T f The idle slot duration T at the start sl .

[0209] 5.2. Type 2 UL channel access procedure

[0210] 5.2.1 Type 2A UL channel access procedure

[0211] If the UE is instructed to perform type 2A UL CAP, the UE uses type 2A UL CAP for UL transmission. The UE can perform transmission immediately after sensing the channel idle for at least the sensing duration T short_ul = 25 us. T short_ul includes a sensing slot duration T sl = 9 us immediately following a slot f = 16 us, and T f includes the sensing slot at the start. If both of the sensing slots within T f are sensed as idle, the channel is considered idle within T short_ul . short_ul within.

[0212] 5.2.2. Type 2B UL channel access procedure

[0213] If the UE is instructed to perform type 2B UL channel access procedure, the UE uses type 2B channel access procedure to perform UL transmission. The UE can perform transmission immediately after the corresponding channel is sensed idle during Tf = 16 us. Tf includes a sensing slot occurring within the last 9 us of Tf. The channel is considered idle during Tf when the channel is sensed to be in the idle state for at least a total of 5 us or longer and for at least 4 us of sensing occurring within the sensing slot.

[0214] 5.2.3. Type 2C UL channel access procedure

[0215] If the UE is instructed to perform type 2C UL channel access procedure, the UE does not sense the channel before performing transmission for transmission. The maximum duration corresponding to the transmission is 584 us.

[0216] 6. Channel access procedure for UL multi-channel transmission

[0217] If the UE:

[0218] - Scheduled to transmit on the channel set C, then the UL scheduling grant indication type 1 CAP for the UL transmission on the channel set C, and the UL transmission is scheduled to start simultaneously for all channels in the channel set C, and / or - If the UE intends to perform UL transmission in the resources configured on the channel set C by type 1 CAP, and

[0219] The channel frequencies of the channel set C are a subset of the preconfigured channel frequency set:

[0220] - The UE can perform transmission on channel c i ∈C by type 2 CAP.

[0221] -- If type 2 CAP was performed on channel c j ∈C (herein, i≠j) immediately before the UE transmission on channel c i and

[0222] -- If the UE has accessed channel c j using type 1 CAP,

[0223] --- Before performing type 1 CAP on any channel in the channel set C, the UE randomly selects channel c j from the channel set C uniformly at random.

[0224] - If the UE fails to access any channel, the UE may not perform transmission on channel c i ∈C within the carrier bandwidth, and the carrier bandwidth is scheduled or configured by UL resources.

[0225] <Uplink Power Control>

[0226] In a wireless communication system, it may be necessary to increase or decrease the transmission (Tx) power of a terminal (e.g., a user equipment (UE) and / or a mobile device) according to the situation. As described above, controlling the transmission power of the UE and / or the mobile device can be referred to as uplink power control. For example, a transmission (Tx) power control method can be applied at a base station (e.g., a gNB, an eNB, etc.) to meet requirements (e.g., signal-to-noise ratio (SNR), bit error rate (BER), block error rate (BLER), etc.).

[0227] As described above, power control can be performed by an open-loop power control method or a closed-loop power control method.

[0228] Specifically, an open-loop power control method refers to a method of controlling the transmission power without feedback from a TX device (e.g., a base station, etc.) to a receiving (Rx) device (e.g., a UE, etc.) and / or feedback from the Rx device to the Tx device. For example, a UE can receive a specific channel / signal (pilot channel / signal) from a base station (BS) and use it to estimate the intensity of the Rx power. Thereafter, the UE can use the estimated intensity of the Rx power to control the transmission power.

[0229] On the other hand, a closed-loop power control method refers to a method of controlling the transmission power based on feedback from the Tx device to the Rx device and / or feedback from the Rx device to the Tx device. For example, the BS receives a specific channel / signal from the UE and estimates the optimal power level of the UE based on the power level, SNR, BEER, BLER, etc. measured via the received specific channel / signal. The BS can send information (i.e., feedback) about the determined optimal power level to the UE through a control channel, etc., and the corresponding UE can use the feedback provided by the BS to control the transmission power.

[0230] Hereinafter, a power control method in the case where a UE and / or a mobile device performs an uplink transmission to a BS in a wireless communication system will be described in detail. Specifically, it describes methods for: 1) an uplink data channel (e.g., a physical uplink shared channel (PUSCH)); 2) an uplink control channel (e.g., a physical uplink control channel (PUCCH)); 3) a sounding reference signal (SRS); and 4) a random access channel (e.g., a physical random access channel (PRACH)) transmission. In this case, (i) the transmission timing (i.e., the Tx time unit) for the PUSCH, PUCCH, SRS, and / or PRACH can be defined by the slot index n_s in the frame of the system frame number (SFN), the first symbol S in the slot, the number of consecutive symbols L, etc.

[0231] (1) Power control of the UL data channel

[0232] Regarding the power control of the uplink data channel, for the sake of description, the power control method will be described below based on the case where the UE performs PUSCH transmission. However, the corresponding power control method is not limited to PUSCH transmission and can be extended and applied to other uplink data channels supported by the wireless communication system.

[0233] In the case of PUSCH transmission on the active UL bandwidth part (BWP) of the carrier (f) of the serving cell (c), the UE can calculate the linear power value of the Tx power determined by the following formula P1. Thereafter, the UE can control the Tx power based on the calculated linear power value considering the number of antenna ports, the number of SRS ports, etc.

[0234] Specifically, when the UE performs PUSCH transmission on the active UL BWP (b) of the carrier (f) of the serving cell (c) using the parameter set configuration based on index j and the PUSCH power control adjustment state based on index l, the UE can determine the PUSCH Tx power P at the PUSCH transmission occasion (i). PUSCH,b,f,c (i,j,q d, l)(dBm).

[0235] [Equation 1]

[0236]

[0237] In Equation 1, index j indicates the index of the open-loop power control parameters (e.g., Po, alpha (α), etc.), and up to 32 parameter sets can be configured per cell. Index q_d indicates the index of the DL RS resource for path loss (PL) measurement (e.g., PL b,f,c (q d ))), and up to 4 measurement values can be configured per cell. Index l indicates the index of the closed-loop power control process, and up to 2 processes can be configured per cell.

[0238] In addition, Po (e.g., P O_PUSCH,b,f,c (j)) is a parameter broadcast as part of the system information and can indicate the target Rx power at the Rx side. The corresponding Po value can be configured considering the throughput of the UE, the capacity of the cell, noise, interference, etc. In addition, α (e.g., α b,f,c (j)) can indicate the ratio for compensating the path loss. α can be configured as a value in the range of 0 to 1, and full path loss compensation or partial path loss compensation can be performed according to the configured value. In this case, the α value can be configured considering inter-UE interference, data speed, etc. In addition, P CMAX,f,c (i) can indicate the configured UE transmission power. For example, the configured UE transmission power can be interpreted as the "configured maximum UE output power" defined in 3GPP TS38.101-1 and / or TS 38.101-2. In addition, can indicate the bandwidth of the PUSCH resource allocation expressed as the number of resource blocks (RBs) for the PUSCH transmission occasion based on the subcarrier spacing (μ). In addition, f related to the PUSCH power control adjustment state can be configured or indicated based on the TPC command field of the DCI (e.g., DCI format 0_0, DCI format 0_1, DCI format 2_2, DCI format 2_3, etc.) b,f,c (i,l).

[0239] In this case, Radio Resource Control (RRC) parameters (e.g., SRI-PUSCHPowerControl-Mapping, etc.) can indicate the association between the SRI (SRS Resource Indicator) field of the Downlink Control Information (DCI) and the above indexes j, q_d, l, etc. Therefore, the above indexes j, q_d, l, etc. can be associated with beams, panels, spatial domain transmission filters, etc. based on specific information. Thus, PUSCH Tx power control can be performed in units of beams, panels, and / or spatial domain transmission filters.

[0240] The above parameters and / or information for PUSCH power control can be configured separately (i.e., independently) for each BWP. In this case, the corresponding parameters and / or information can be configured or indicated through higher layer signaling (e.g., RRC signaling, Medium Access Control - Control Element (MAC-CE), etc.), DCI, etc. For example, the parameters and / or information for PUSCH power control can be transmitted through RRC signaling such as PUSCH-ConfigCommon, PUSCH-PowerControl, etc.

[0241] (2) Power control of the uplink control channel

[0242] Regarding the power control of the uplink data channel, for the sake of convenient description, the power control method will be described below based on the case where the UE performs PUCCH transmission. However, the corresponding power control method is not limited to PUCCH transmission and can be extended and applied to other uplink data channels supported by the wireless communication system.

[0243] When the UE uses the PUCCH power control adjustment state based on index l to perform PUCCH transmission on the active UL BWP (b) of the carrier (f) of the primary cell (or secondary cell) (c), the UE can determine the PUCCH transmission power P on the PUCCH transmission occasion (i) based on the following formula 2 PUCCH,b,f,c (i,q u, q d, l)(dBm).

[0244] [Formula 2]

[0245]

[0246] In Formula 2, q_u indicates the index of the open-loop power control parameter (e.g., Po, etc.), and up to 8 parameter values can be configured for each cell. The index q_d indicates the index of the DL RS resource for path loss (PL) measurement (e.g., PL b,f,c (q d )) and up to 4 measurement values can be configured for each cell. The index l indicates the index of the closed-loop power control process, and up to 2 processes can be configured for each cell.

[0247] In addition, Po (e.g., P O_PUCCH,b,f,c (q u )) is a parameter broadcast as part of the system information and can indicate the target Rx power at the Rx side. The corresponding Po value can be configured considering the throughput of the UE, the capacity of the cell, noise, interference, etc. In addition, P CMAX,f,c (i) can indicate the configured UE transmit power. For example, the configured UE transmit power can be interpreted as the "configured maximum UE output power" defined in 3GPP TS38.101-1 and / or TS 38.101-2. In addition, can indicate the bandwidth of the PUCCH resource allocation expressed as the number of resource blocks (RBs) for the PUCCH transmission occasion based on the subcarrier spacing (μ). In addition, the Δ function (e.g., Δ F_PUCCH (F), Δ TF,b,f,c (i)) can be configured considering the PUCCH format (e.g., PUCCH format 0, 1, 2, 3, 4, etc.). In addition, g b,f,c (i, l) related to the PUCCH power control adjustment state can be configured or indicated based on the TPC command field of the DCI (e.g., etc.) received or detected by the UE.

[0248] In this case, specific RRC parameters (e.g., PUCCH-SpatialRelationInfo, etc.) and / or specific MAC-CE commands (e.g., PUCCH spatial relation enable / disable, etc.) can be used to enable or disable the association between the PUCCH resource and the above indexes q_u and q_d. For example, the PUCCH spatial relation enable / disable command in the MAC-CE can enable or disable the association between the PUCCH resource and the above indexes q_u, q_d, and l based on the RRC parameter PUCCH-SpatialRelationInfo. Therefore, the above indexes q_u, q_d, l, etc. can be associated with beams, panels, spatial domain transmission filters, etc. based on specific information. Thus, PUCCH Tx power control can be performed in units of beams, panels, and / or spatial domain transmission filters.

[0249] The above parameters and / or information for PUCCH power control can be configured separately (i.e., independently) for each BWP. In this case, the corresponding parameters and / or information can be configured or indicated through higher layer signaling (e.g., RRC signaling, Medium Access Control - Control Element (MAC-CE), etc.), DCI, etc. For example, the parameters and / or information for PUCCH power control can be transmitted through the RRC signaling PUCCH-ConfigCommon, PUCCH-PowerControl, etc.

[0250] (3) Power control of the random access channel

[0251] When the UE performs PRACH transmission on the active UL BWP (b) of the carrier (f) of the serving cell (c), the UE may determine the PRACH transmission power P at the PRACH transmission occasion (i) based on Equation 3 below PRACH,b,f,c (i) (dBm).

[0252] [Equation 3]

[0253] P PRACH,b,f,c (i) = min{P CMAX,f,c (i), P PRACH,target,f,c + PL b,f,c}}

[0254] In Equation 3, P CMAX,f,c (i) may indicate the configured UE transmission power. For example, the configured UE transmission power may be interpreted as the "configured maximum UE output power" defined in 3GPP TS 38.101-1 and / or TS38.101-2. Additionally, P PRACH,target,f,c indicates the PRACH target received power provided by the higher layer signaling (e.g., RRC signaling, MAC-CE, etc.) of the active UL BWP. Additionally, PL b,f,c indicates the path loss of the active UL BWP and may be determined based on the DL RS associated with the PRACH transmission on the active DL BWP of the serving cell (c). For example, the UE may determine the path loss related to the PRACH transmission based on the synchronization signal / physical broadcast channel (SS / PBCH) block, etc., associated with the PRACH transmission.

[0255] The above parameters and / or information for PRACH power control may be configured separately (i.e., independently) for each BWP. In this case, the corresponding parameters and / or information may be configured or indicated by higher layer signaling (e.g., RRC signaling, MAC-CE, etc.). For example, the parameters and / or information for PRACH power control may be transmitted through RRC signaling such as RACH-ConfigGeneric, etc.

[0256] (4) Tx power control procedure

[0257] Figure 6 is a diagram describing an implementation of the procedure for controlling the uplink transmission power.

[0258] First, a user equipment (UE) may receive parameters and / or information related to transmission (Tx) power from a base station (BS)

[605] . In this case, the UE may receive the parameters and / or information via higher layer signaling (e.g., RRC signaling, MAC-CE, etc.). For example, regarding PUSCH transmission, PUCCH transmission, SRS transmission, and / or PRACH transmission, the UE may receive parameters and / or information related to the above Tx power control.

[0259] Thereafter, the UE may receive a transmit power control (TPC) command related to Tx power from the BS

[610] . In this case, the UE may receive the corresponding TPC command via lower layer signaling (e.g., DCI, etc.). For example, regarding PUSCH transmission, PUCCH transmission, and / or SRS transmission, as described above, the UE may receive information on the TPC command to be used for determining a power control adjustment state, etc., via the TPC command field of a predetermined DCI format. However, in the case of PRACH transmission, the corresponding step may be skipped.

[0260] Thereafter, based on the parameters, information, and / or TPC command received from the BS, the UE may determine (or calculate) the Tx power for uplink (UL) transmission

[615] . For example, based on the above methods (e.g., Equation 1, Equation 2, Equation 3, etc.), the UE may determine the PUSCH Tx power, PUCCH Tx power, SRS Tx power, and / or PRACH Tx power. And / or, in a case similar to carrier aggregation, if two or more UL channels and / or signals need to be transmitted by overlapping each other, the UE may consider the above priorities, etc., to determine the Tx power for UL transmission.

[0261] Thereafter, based on the determined (or calculated) Tx power, the UE may perform the transmission of one or more UL channels and / or signals (e.g., PUSCH, PUCCH, SRS, PRACH, etc.) to the BS

[620] .

[0262] Before the detailed description, reference will be made to Figure 7 and Figure 8 to describe examples of implementing the operations of the UE and the BS according to embodiments of the present disclosure.

[0263] Figure 7 is a diagram illustrating an example implementation of the operation of a UE according to an embodiment of the present disclosure. Referring to Figure 7 , a message A including a first PRACH (physical random access channel) and a first PUSCH (physical uplink shared channel) may be transmitted [S701]. Thereafter, the UE may receive a message B related to contention resolution in response to message A [S703]. In this case, the specific methods for the UE to transmit message A and receive message B in S701 to S703 may be based on the embodiments and features described below.

[0264] In addition, Figure 7 the UE of Figures 14 to 17 can be any one of various wireless devices disclosed in Figure 7 the UE of Figure 14 can be the first wireless device 100 of Figure 15 or the wireless devices 100 and 200 of Figure 7 That is to say, the operation and processing of Figure 14 and Figure 15 can be executed by any one of various wireless devices disclosed in

[0265] Figure 8 is a diagram illustrating an implementation example of the operation of a base station according to an embodiment of the present disclosure. Referring to Figure 8 , the BS may receive a message A [S801] including a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel). Thereafter, the BS may send a message B [S803] related to contention resolution in response to the message A. In this case, the specific methods for the BS to receive the message A and send the message B in S801 to S803 may be based on the embodiments and features described below.

[0266] In addition, Figure 8 the BS of Figures 14 to 17 can be any one of various wireless devices disclosed in Figure 8 the BS of Figure 14 can be the second wireless device 200 of Figure 15 or the wireless devices 100 and 200 of Figure 8 That is to say, the operation and processing of Figures 14 to 17 can be executed by any one of various wireless devices disclosed in

[0267] Hereinafter, in steps S701 and S801 of sending and receiving a message A including a first PRACH and a first PUSCH, specific embodiments in which the UE determines the Tx power of the message A based on the TX beam direction will be described.

[0268] In the LTE and / or NR system, the UE can perform UL transmission through a random access process (RACH process) without receiving scheduling for direct uplink (UL) transmission from a given BS or cell. From the perspective of the UE, the random access process in the LTE and / or NR system includes a 4-step process: 1) transmission of a random access preamble; 2) reception of a message (Msg) 2 corresponding to a random access response (RAR); 3) transmission of Msg 3 including a physical uplink shared channel (PUSCH); and 4) reception of Msg 4 including information about contention resolution.

[0269] Here, Msg 2 is a message in which the BS that has received the random preamble allocates UL resources that the UE transmitting the preamble will use to transmit Msg 3. Through Msg3, the UE can send information about the connection request and its identification information, such as the International Mobile Subscriber Identity (IMSI), Temporary Mobile Subscriber Identity (TMSI), etc. The BS that has received Msg3 sends the identification information of the corresponding UE and the information required for random access through Msg4, thereby preventing possible collisions between different UEs during the random access process and completing the random access process of the corresponding UE.

[0270] Different from the RACH process configured in 4 steps as described above in traditional LTE and NR Rel-15, in NR Rel-16, efforts are being made to research and develop a 2-step RACH process to simplify the processing delay caused by the 4 steps and apply the RACH process to small cells or unlicensed bandwidth. In the 2-step RACH, the steps of sending Msg 3 (Msg3) containing the Physical Uplink Shared Channel (PUSCH) and the step of sending Msg 4 containing a contention resolution message, etc. in the existing 4-step RACH are omitted. Instead, in the first step of the random access process, the UE directly sends the message corresponding to Msg3 together with the preamble to the BS. In response to MsgA, the BS sends Msg 4 as the message corresponding to Msg4 together with the RAR to the UE. When receiving Msg B, the UE decodes Msg B to complete the random access process and then performs data transmission / reception.

[0271] Figure 9 is a diagram showing the basic processing of the 2-step RACH. Referring to Figure 9 , the UE can receive the 2-step RACH-related configuration information [S901] included in the system information broadcast from the BS. When receiving the 2-step RACH-related configuration information, the UE performs a random access process to the BS by sending Msg A including a RACH preamble (or PRACH preamble) and PUSCH based on the corresponding configuration information [S903]. When doing so, the RACH preamble and PUSCH can be sent with a predetermined gap therebetween or continuously in the time domain, and the identifier (ID) information of the UE is included in the corresponding PUSCH. The BS can detect the preamble, thereby predicting and receiving the PUSCH with the corresponding gap or the continuous PUSCH. The BS receives the access request and / or response from the higher layer based on the ID information of the UE sent through the PUSCH, and then sends MsgB including information such as RAR, contention resolution, etc. to the UE in response to Msg A [S905]. Thereafter, depending on whether the UE receives MsgB, the UE can complete the access to the BS and transceive data with the BS in the same or similar manner as after the operation of receiving Msg4 in the existing 4-step RACH process.

[0272] In the following disclosure, various embodiments applicable to the two-step RACH process will be reviewed. Specifically, a method for configuring the Msg-A Tx power according to the listen-before-talk (LBT) performed on the unlicensed band and a method for configuring the PUCCH resources for the HARQ-ACK transmission of the UE in response to MsgB will be described in detail.

[0273] Two-step RACH process based on LBT on the unlicensed band

[0274] In NR, since the UE can perform the random access process on the unlicensed band, the listen-before-talk (LBT) required for signal transmission / reception on the unlicensed band can also be applied to the signal transmission / reception of the random access process. That is, in the NR-unlicensed (NR-U) spectrum system, the BS and the UE always perform LBT before transmitting and receiving signals to check the idle or busy state of the Tx / Rx channel, which can be performed in the same way during the transmission / reception of Msg A and Msg B for the two-step RACH process on the unlicensed band.

[0275] Since the transmission of Msg A in the two-step RACH process includes the transmission of Msg A PUSCH and the transmission of Msg A RACH preamble, the subsequent random access process can vary according to the success or failure of the LBT for the Msg A PRACH preamble and Msg A PUSCH. For example, if the UE successfully performs LBT before the transmission of the Msg A PRACH preamble and Msg A PUSCH and transmits up to Msg A PUSCH without any problems, the BS can correctly receive both the Msg A PRACH preamble and Msg A PUSCH, send Msg B including the contention resolution information to the UE, and complete the two-step RACH process. On the contrary, if the LBT of the UE for the Msg A PRACH preamble or Msg A PUSCH fails, the UE may not be able to successfully transmit Msg A. The BS that fails to receive Msg A can give an indication to retransmit Msg A or fallback to the four-step RACH process.

[0276] In this case, considering that Msg A conceptually includes both the Msg A PRACH preamble and the Msg A PUSCH, whether to retransmit Msg A based on the LBT failure can be handled differently according to the time gap between the Msg A PRACH preamble Tx time and the Msg A PUSCH Tx time. That is, the retransmission process of Msg A can vary depending on whether the UE continuously transmits the Msg A PUSCH after transmitting the Msg A PRACH preamble or there is a time gap greater than the minimum time required for LBT before transmitting the Msg A PUSCH after transmitting the Msg A PRACH preamble.

[0277] (1) The case where the Msg A PRACH preamble and the Msg A PUSCH are transmitted continuously

[0278] In the case where the Msg A PRACH preamble and the Msg A PUSCH are transmitted continuously, it can refer to the case where the Msg A PRACH preamble and the Msg A PUSCH are transmitted continuously in a single time slot or the case where the Msg A PRACH preamble and the linked Msg A PUSCH are transmitted in consecutive time slots.

[0279] That is, the case where the Msg A PRACH preamble and the Msg A PUSCH are transmitted continuously includes the case where there is no time gap equivalent to the minimum time required for LBT between the transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH, as Figure 10 The case shown can be an example of this.

[0280] Figure 10 FIG. is a diagram showing an embodiment of Msg A transmission according to the success or failure of LBT of the UE and the transmission beam direction configuration. Figure 10 FIG. (a) shows that when the LBT is successful at a specific timing, the UE continuously transmits the Msg A PRACH preamble and the Msg A PUSCH. Figure 10 FIG. (b) shows that when the LBT fails at a specific timing and the LBT is successful at the next timing, the UE continuously transmits the Msg A PRACH preamble and the Msg A PUSCH. Since in Figure 10 FIG. (a) and Figure 10In (b) of this case, there is no time gap equivalent to the LBT required condition time between the Tx timing of the Msg A PRACH preamble and the Tx timing of the Msg A PUSCH. Therefore, the UE only performs LBT before transmitting the Msg A PRACH preamble and performs continuous transmission without performing LBT when sending the Msg A PUSCH intact. Thus, for this case, the signal transmission operations of the UE and the BS and the power control of their signal transmissions can be configured differently according to the success or failure of the LBT performed before transmitting the Msg A PRACH preamble.

[0281] If the UE fails in the LBT for the Msg A PRACH preamble transmission at a predetermined timing, the UE can perform the LBT for the Msg A PRACH preamble transmission again for the next RACH opportunity (RO) after an associated period from the LBT failure timing. Alternatively, if the UE fails in the LBT for the Msg A PRACH preamble transmission at a predetermined timing, the UE restarts the random access resource selection process, performs SSB selection based on the reference signal received power (RSRP) of the SSB (synchronization signal and physical broadcast channel (SS / PBCH)) or the channel state information-reference signal (CSI-RS), and selects the RO and the random access preamble index (RAPID) associated with the SSB, so as to send the Msg A PRACH preamble on the corresponding RO, and the UE can also continuously send the Msg A PUSCH. Additionally, since the continuously transmitted Msg A PUSCH has a transmission channel state different from the previous Tx environment, the content and modulation order included in the Msg A PUSCH can be configured differently from the previous Msg A PUSCH transmission to meet the channel environment for sending the Msg A PUSCH. For example, when the state of the channel is good at the Msg A PUSCH Tx timing, the UE can send a Msg A PUSCH including a larger amount of information and can apply a high modulation order to it.

[0282] Here, in the case of Msg A, since the Msg A PUSCH is sent after the Msg A PRACH preamble transmission and before the BS feedback, Tx factors such as the maximum Tx count, incremental step size, power increment counter, etc. of Msg A retransmission need to be configured separately. Specifically, for the configuration of the power increment counter and the maximum Tx count of Msg A among these factors, specific methods described later can be considered.

[0283] First, in the case of a power ramp counter, since Msg A PRACH preambles and Msg A PUSCH are transmitted continuously, it may be appropriate to use a common power ramp counter for Msg A PRACH preambles and Msg A PUSCH. If the UE fails to transmit a Msg A PRACH preamble on a determined RO according to LBT, the UE may perform LBT again on the next RO as shown in (b) of Figure 10 and then transmit the Msg A PRACH preamble after successful LBT. In this case, for re - performing LBT and transmitting the Msg A PRACH preamble at successful LBT, the UE may configure the power ramp counter with a value that maintains or increases by comparing it with the power ramp counter that should be configured to transmit the Msg A PRACH preamble in the case of a previous LBT failure. Here, the power ramp counter mentioned in the present disclosure may refer to the power ramp counter for general re - transmission.

[0284] 1) Method of configuring Tx power by maintaining the ramp counter with the same value as before

[0285] The UE may first maintain the value of the power ramp counter as it is. That is, if due to LBT failure on a previous RO, the UE performs LBT on the next RO and succeeds in LBT and then transmits Msg A, since from the UE's perspective, Msg A is basically not transmitted on the previous RO, randomly increasing the UE's Tx power may result in inefficient power waste. As a result, the UE may transmit Msg A by maintaining the initially expected Tx power by maintaining the value of the power ramp counter as it is.

[0286] 2) Method of configuring Tx power by configuring the ramp counter to increase to a value higher than before

[0287] The UE can determine the Tx power by increasing the value of the power ramp counter. Although the UE performs LBT successfully on the next RO by performing LBT on the next RO due to the LBT failure of the previous RO and then sends Msg A, the UE can determine the Tx power by configuring the power ramp counter in a way that increases the previous value by +1. If the Msg A Tx power is determined by applying the power ramp counter increased by +1, considering that other UEs that have attempted the same RACH at the timing of the previous RO can attempt the RACH at the timing of the next RO with the Tx power increased by ramping up the power, the problem that it is difficult to detect the Msg A PRACH preamble of the UE due to a relatively small Tx power can be prevented. Additionally, the purpose of introducing the two-step RACH procedure is to further reduce the latency that occurs in the four-step RACH procedure as much as possible. Therefore, for fast network access when the latency lags due to LBT in NR-U, different from the four-step RACH procedure, the latency can be reduced a little by increasing the detection probability by having the UE consume additional power for each retransmission. For these reasons, when the UE sends Msg A on the next RO due to the LBT failure of the previous RO, the UE can regard the LBT failure of the previous RO as a Msg A transmission failure, increase the power ramp counter by +1, and then apply it to the transmission of the Msg A PRACH preamble and the Msg A PUSCH.

[0288] 3) Method for configuring Tx power by maintaining or increasing a power ramp counter according to the Tx beam direction

[0289] Considering the advantages and disadvantages of the above methods 1) and 2), the UE can use the method of maintaining or increasing the power ramp counter according to the Tx beam direction. That is, different from method 1) of maintaining the power regardless of the beam direction and method 2) of increasing the power regardless of the beam direction, according to the corresponding method, the UE determines the LBT failure of the previous RO as a retransmission, but increases or maintains the power ramp counter according to the Tx beam of the UE.

[0290] Figure 11 is a diagram showing maintaining or increasing a power ramp counter according to the Tx direction of the UE according to an embodiment of the present disclosure. As Figure 11 (a) of shows, when the Tx spatial beam configured at the time of the LBT failure of the previous RO is different from the Tx spatial beam configured at the time of the LBT success of the next RO, the UE can send Msg A by maintaining the power ramp counter with the same value as before. On the contrary, as Figure 11 (b) of shows, when the Tx spatial beam configured at the time of the LBT failure of the previous RO is the same as the Tx spatial beam configured at the time of the LBT success of the next RO, the UE can send Msg A by increasing the power ramp counter to be higher than before.

[0291] In summary, when the LBT for the transmission or retransmission of MsgA is not indicated to the UE and fails in transmitting or retransmitting MsgA, the UE configures the Tx power by maintaining or increasing the power ramp counter according to whether the Tx spatial beam direction is equal to that of the previous transmission or retransmission of MsgA. In this case, since the Tx spatial beam direction for the transmission or retransmission of MsgA can be associated with the SSB selected by the UE for the transmission or retransmission of MsgA, the UE can be interpreted as configuring the Tx power by maintaining or increasing the power ramp counter according to whether the SSB selected by the UE for the transmission or retransmission of MsgA is the same as the SSB selected for the previous transmission or retransmission of MsgA. Additionally, considering the continuous transmission of Msg A PRACH and Msg A PUSCH, the Tx spatial beam direction for the previous transmission or retransmission of MsgA can be conceptually understood to include the Tx spatial beam direction configured for the previous transmission or retransmission of PRACH.

[0292] For example, when the UE transmits or retransmits MsgA, if it does not receive an indication of LBT failure for the transmission or retransmission of the corresponding MsgA from the lower layer, the UE compares the SSB it has selected with the SSB selected for the previous transmission or retransmission of PRACH. If the SSB it has selected has not changed, the UE can transmit MsgA by configuring the Tx power in such a way that the power ramp counter is increased by 1 compared to the previous value. Alternatively, when the UE transmits or retransmits MsgA, if it does not receive an indication of LBT failure for the transmission or retransmission of the corresponding MsgA from the lower layer, the UE compares the SSB it has selected with the SSB selected for the previous transmission or retransmission of PRACH. If the SSB it has selected has changed, the UE can transmit MsgA by configuring the Tx power in such a way that the power ramp counter is maintained at the same value as the previous one.

[0293] When the UE transmits or retransmits MsgA, if it receives an indication of LBT failure for the transmission or retransmission of the corresponding MsgA, the UE performs retransmission by determining this LBT failure as a retransmission. When doing so, if an indication of LBT failure recovery is configured in the UE, the UE can perform a random access resource selection process for the two-step RACH procedure.

[0294] 4) A method for configuring Tx power by maintaining or increasing a power ramp counter according to the relationship between the RO of the two-step RACH procedure and the RO of the four-step RACH procedure

[0295] The UE can maintain or increase the power ramp counter according to the relationship between the RO of the two-step RACH procedure and the RO of the four-step RACH procedure. That is, according to whether the RO of the two-step RACH procedure and the RO of the four-step RACH procedure are shared with each other or configured separately from each other.

[0296] The ROs for the two-step RACH procedure and the four-step RACH procedure can be basically shared. Here, if the ROs are shared, it means that the Msg 1 preamble in the four-step RACH procedure and the Msg A PRACH preamble in the two-step RACH procedure are transmitted on the same RO. Additionally, if the ROs are configured separately from each other, it means that the time / frequency resources of the Msg 1 preamble in the four-step RACH procedure and the time / frequency resources of the Msg A PRACH preamble in the two-step RACH procedure exist independently of each other.

[0297] The above methods 1) to 3) handle operations in the UE and the BS regardless of whether the ROs are shared or configured separately from each other. Therefore, the corresponding methods apply different power increment counter determination methods depending on whether the ROs are shared or configured separately from each other. That is, when the ROs for the two-step RACH procedure and the four-step RACH procedure are configured separately from each other, similar to the above methods 2) and 3), the UE performing the two-step RACH procedure increases the value of the power increment counter for retransmission by recognizing an LBT failure on the RO as a transmit / receive (Tx / Rx) failure. On the other hand, when the ROs for the two-step RACH procedure and the four-step RACH procedure are shared with each other, the UE maintains the value of the power increment counter in the same manner as the existing four-step RACH procedure in NR-U, similar to the above method 1), without separating the two-step RACH procedure and the four-step RACH procedure.

[0298] Furthermore, the maximum Tx count for Msg A in the two-step RACH procedure can be given separately from that in the four-step RACH procedure, and if no separately given value exists, the maximum Tx count configured for Msg 1 in the four-step RACH procedure can be followed. If the value of the power increment counter is configured to be 1 greater than the maximum Tx count of Msg A, the UE can perform a reconstruction procedure based on a radio link failure (RLF). Additionally, when the ROs for the two-step RACH procedure and the four-step RACH procedure are shared with each other, if the maximum Tx count of Msg1 in the four-step RACH procedure is configured to be greater than Msg A in the two-step RACH procedure, the UE can transmit Msg 1 only from the time when the power increment counter becomes 1 greater than the maximum Tx count of Msg A. Additionally, the increment step value can be used to determine the Tx power for retransmission by applying the increment step to Msg 1 from the time when the power increment counter becomes 1 greater than the maximum Tx count of Msg A. In this case, the UE's fallback and RLF operations regarding the values and maximum values of each counter can apply not only to NR-U but also to NR.

[0299] (2) Case where there is a time gap between the transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH

[0300] The corresponding situation means that there is a time gap greater than the minimum time required for LBT from after the transmission of the Msg A PRACH preamble until the UE transmits the Msg A PUSCH. Since the transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH are performed discontinuously with a predetermined gap, the UE performs LBT for both the transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH. Therefore, the operations of the UE and the BS can vary differently depending on whether the LBT at the Tx timing of each signal is successful or not. In addition, since there is a spacing between the Tx timings of each signal, the beam direction determined according to the channel state can also vary, and thus the power configuration for retransmission can also be complex. Hereinafter, the operations and Tx power configurations of the UE and the BS according to the failure timing of LBT for the transmission of the Msg A PRACH preamble and the Msg A PUSCH will be described.

[0301] Regarding the configuration of the power ramp counter in the above situation, since the Msg A PRACH preamble and the Msg A PUSCH are transmitted with a predetermined gap, it is possible to consider both a signal counter that shares the power ramp counter for use in the retransmission power configuration of the Msg A PRACH preamble and the Msg A PUSCH and a dual counter that is configured to use the power ramp counter for the respective retransmission power configurations of the Msg A PRACH preamble and the Msg A PUSCH. In addition, the maximum Tx count of Msg A is not commonly applied to the Msg A PRACH preamble and the Msg A PUSCH, but the maximum Tx count for each of the Msg A PRACH preamble and the Msg A PUSCH can be configured.

[0302] In this case, when using a single power ramp counter, the condition for increasing or maintaining the value of the counter can be whether the direction of the Tx spatial beam for the transmission of the Msg A PRACH preamble in the Msg A retransmission changes. That is, if the direction of the Tx spatial beam for the transmission of the Msg A PRACH preamble is the same as the previous transmission, the counter value is increased. If the direction of the Tx spatial beam for the transmission of the Msg A PRACH preamble is different from the previous transmission, the counter value is maintained. In addition, when using a dual power ramp counter, the condition for increasing or maintaining the value of each counter can be whether the direction of the Tx spatial beam for each of the Msg A PRACH preamble and the Msg A PUSCH changes compared to the previous transmission. That is, for the Msg A PRACH preamble and the Msg A PUSCH, if the direction of the Tx spatial beam for the transmission of each signal is the same as the previous transmission, the value of each counter is increased, or if the direction of the Tx spatial beam for the transmission of each signal is different from the previous transmission, the value of each counter is maintained.

[0303] For reference, the term "retry" as mentioned in the present disclosure means that the Msg A PRACH preamble is not sent on the original RO due to LBT failure but is sent on the next RO, or the Msg A PUSCH is not sent on the original PO due to LBT failure but is sent on the next PO. Although the originally intended Msg A PRACH preamble cannot be sent due to LBT failure, the case of sending a different Msg A PRACH preamble on the originally scheduled RO does not mean "retry" as mentioned in the present disclosure, and in this case, the counter value is not incremented either. The increment and maintenance of the power ramp counter for retransmission of each signal included in Msg A, the maximum retransmission count, and the operations of the UE and BS in case of LBT failure will be described below in a manner divided into the case of LBT failure before Msg A PRACH preamble transmission and the case of LBT failure before Msg A PUSCH transmission.

[0304] 1) LBT failure before Msg A PRACH preamble transmission

[0305] When the UE uses a single power ramp counter for both the Msg A PRACH preamble and the Msg A PUSCH, if LBT fails before Msg A PRACH preamble transmission, the UE may increment or maintain the corresponding common power ramp counter value according to the above-described embodiments for the case of continuously sending the Msg A PRACH preamble and the Msg A PUSCH. Additionally, when the UE uses dual power ramp counters for the Msg A PRACH preamble and the Msg A PUSCH, if LBT fails before Msg A PRACH preamble transmission, the values of the counters for each of the Msg A PRACH preamble and the Msg A PUSCH may be incremented or maintained independently. Specifically, if the Tx spatial beam direction configured for the transmission of each signal is the same as the previous transmission, the value of each counter is incremented. If the Tx spatial beam direction configured for the transmission of each signal is different from the previous transmission, the value of each counter is maintained.

[0306] In this case, if a UE that has experienced LBT failure before Msg A PRACH preamble transmission retries the transmission of Msg A, the UE may continuously send Msg A or fallback to sending only Msg 1 in 4 steps. Depending on each method, the operations of the UE and the BS may change.

[0307] (a) First, if the UE fails to send the Msg A PRACH preamble due to LBT failure for a specific RO, the UE may attempt to transmit the Msg A PRACH preamble again on the next RO. When doing so, the UE may attempt to transmit the Msg A PRACH preamble by differently selecting the SSB according to the channel measured for the Msg A PRACH preamble transmission and randomly selecting a RAPID from the preambles set for two steps associated with the selected SSB. When a single power ramp counter is configured, if the Msg A PRACH preamble is retransmitted according to the Tx beam direction same as the Tx beam direction used for the previous Msg A PRACH preamble transmission, the value of the corresponding counter increases. Alternatively, if the Msg A PRACH preamble is retransmitted according to a beam direction different from the Tx beam direction used for the previous Msg A PRACH preamble transmission, the value of the corresponding counter remains equal to the previous value. When a dual power ramp counter is configured, the value of the counter for each of the Msg A PRACH preamble and the Msg A PUSCH may increase or remain independently. Specifically, if the Tx spatial beam direction configured for the transmission of each signal is the same as the Tx spatial beam direction configured for the previous transmission, the value of each counter increases. If the Tx spatial beam direction configured for the transmission of each signal is different from the Tx spatial beam direction configured for the previous transmission, the value of each counter remains.

[0308] (b) If the UE fails to send the Msg A PRACH preamble due to LBT failure for a specific RO, the UE may not send the Msg A PRACH preamble but instead send only Msg 1 on the next RO. That is, the UE may fallback to the 4-step RACH procedure. In the case of a channel occupied by another UE or occupied for the transmission of a different signal, since it is likely that the channel adjacent to the next LBT is also occupied, the corresponding method is a method of efficiently using resources by sending only Msg 1 without reserving the time / frequency resources allocated for the Msg A PUSCH. In this case, although the UE sends Msg 1 using the preamble index of the 2-step RACH procedure, the BS waits until the maximum Tx available time of the Msg A PUSCH with reference to the detection time of Msg A, and if the corresponding time expires, the BS sends Msg 2 in response to Msg 1 and performs the 4-step RACH procedure. Here, similar to the target reception power of Msg 1, the Tx power of Msg 1 may be configured based on the configuration of Msg 1 used in the 4-step RACH procedure.

[0309] 2) LBT failure before Msg A PUSCH transmission

[0310] When the UE fails in LBT before Msg A PUSCH transmission, the operation of the UE may change according to whether the PO is configured to include a time gap for LBT or whether the PO is configured not to include a time gap for LBT.

[0311] In this case, if the PO is configured to include a time gap for LBT, the UE performs LBT within the time gap for the corresponding LBT. If the LBT is successful, the UE may transmit Msg A PUSCH simultaneously with the success. Alternatively, the UE performs LBT within the time gap for the corresponding LBT. If the LBT is successful, the UE may transmit a random signal preconfigured exclusively for the channel before the start symbol of Msg A PUSCH until the timing at which Msg A PUSCH was originally intended to be transmitted, and then transmit Msg A PUSCH from the start symbol of Msg A PUSCH.

[0312] On the other hand, when the PO is configured not to include a time gap for LBT, if the UE performs LBT before the corresponding PO and fails to successfully perform LBT until the start symbol of the corresponding PO, similar to the embodiments described below, the UE may perform LBT to transmit Msg A PUSCH only on the next PO and attempt transmission of Msg A PUSCH, may perform LBT again to transmit a Msg A PRACH preamble on the next RO and re-attempt transmission of Msg A, or may fallback to the 4-step RACH procedure by transmitting only Msg 1.

[0313] (a) First, considering that Msg A PRACH preambles have been sent, the UE may only send Msg A PUSCH. In this case, when the Msg A PRACH preambles and POs are in a many-to-one mapping relationship or a one-to-one mapping relationship, the Tx timing of Msg A PUSCH is performed on the resources of the next PO. In this case, since the UE does not retransmit Msg A PRACH, the resources used for Msg A PUSCH transmission are the same Msg A PUSCH resources associated with the RAPID used for the previous transmission. However, in order to distinguish whether the transmission of Msg A PUSCH is a retransmission due to a previous LBT failure or a current Msg A PUSCH transmission attempt, Msg A PUSCH should be able to include information about the retransmission, and the BS should also be able to convey via Msg B whether it is a response to the nth previous RAPID based on the corresponding information. Additionally, the UE will identify the Msg A PUSCH transmission attempt caused by an LBT failure as a retransmission, so that the UE can increase or maintain the value of the power ramp counter for the Tx power configuration of Msg A PUSCH for the case of continuously sending Msg A PRACH preambles and Msg A PUSCH according to the above embodiments.

[0314] On the other hand, when the Msg A PRACH preambles and POs are in a one-to-one mapping relationship, the UE only sends Msg A PUSCH by performing LBT before or within multiple POs. If channel estimation can be performed among multiple POs, the value of the power ramp counter for the Tx power of Msg A PUSCH increases if the Tx spatial beam direction of Msg A PUSCH is the same as the previous transmission, or is maintained if the Tx spatial beam direction of Msg A PUSCH is different from the previous transmission. In this case, if a dual power ramp counter is configured for each of Msg A PRACH and Msg A PUSCH, the corresponding counter may only indicate the retransmission counter for Msg A PUSCH.

[0315] (b) The UE may newly select a Msg A PRACH preamble for an LBT failure before Msg A PUSCH transmission and may send the Msg A PUSCH on the PO associated therewith. In the case of the above method of sending only the Msg A PUSCH, the following additional mechanism is required. Information about Msg A PRACH preamble transmission should be conveyed through the content of the Msg A PUSCH. Thereby, the BS obtains whether there is a current LBT failure of the UE, makes a response by distinguishing the UE's current Tx timing and past Tx timing, and conveys relevant information. On the other hand, according to this method, if the UE fails to send the Msg A PUSCH, the UE may select and send the Msg A PRACH preamble on the next RO, and the BS may anticipate the reception of the Msg A PUSCH by estimating the timing advance (TA) value based on the corresponding Msg A PRACH preamble. In this case, the Tx power for the Msg A PRACH preamble may be allocated based on the UE increasing or maintaining the value of the power ramp counter for the Tx power configuration of the Msg A PUSCH according to the above-described embodiment for the case of continuously sending the Msg A PRACH preamble and the Msg A PUSCH. If a dual power ramp counter is used, whether to increase or maintain the power ramp counter for each signal may be configured differently according to whether the Tx spatial beam direction for each of the Msg A PRACH preamble and the Msg A PUSCH changes.

[0316] (c) Since the Msg A PRACH preamble has been sent, the UE may anticipate receiving a response to the Msg A PRACH preamble without sending the Msg A PUSCH by determining that the BS has received only the preamble. Although the UE uses the preamble index of the two-step RACH procedure to send Msg 1, the BS waits until the maximum transmit time of the Msg A PUSCH with reference to the detection time of Msg A. If the corresponding time expires, the BS determines that the transmission has failed due to LBT, and then conveys the information required for Msg 3 transmission to the UE via Msg B. Since the UE has only sent the Msg A PRACH preamble, the UE automatically estimates a fallback to the four-step RACH procedure and anticipates receiving the information required for Msg 3 transmission via Msg B. Thereafter, the UE receives Msg B and may use the information included in Msg B to send Msg 3.

[0317] Configuration of HARQ-ACK resources for Msg B

[0318] In the case of Msg B sent by the BS to the UE, since a response for a single UE or multiple UEs is sent, the BS needs to specify the resources for the Hybrid Automatic Repeat reQuest - Acknowledgement (HARQ-ACK) transmission from the UE. Hereinafter, the PUCCH resource configuration for transmitting HARQ-ACK for the UE will be described.

[0319] In the 4-step RACH procedure on the NR system, the BS can use the PDCCH (DCI) of Msg 4 to specify the resources for the PUCCH to be sent by the UE in a UE-specific manner. When the PDCCH for scheduling Msg 4 is configured with DCI format 1_0 scrambled with a Temporary Cell - Radio Network Temporary Identifier (TC-RNTI), different from the case of DCI format 1_0 scrambled with a Random Access - RNTI (RA-RNTI), the five DCI field elements other than the 1 bit for indicating the DCI format can be additionally indicated as follows.

[0320] - TPC command for the scheduled PUCCH – 2 bits, defined in Subclause 7.2.1 of TS38.213

[0321] - PUCCH resource indicator – 3 bits, defined in Subclause 9.2.3 of TS38.213

[0322] - PDSCH-to-HARQ_feedback timing indicator – 3 bits, defined in Subclause 9.2.3 of TS38.213

[0323] - HARQ process number – 4 bits

[0324] - Downlink assignment index – 2 bits, reserved

[0325] Specifically, among the above field elements indicated by the DCI, the maximum 3-bit PUCCH resource indicator and the 3-bit PDSCH-to-HARQ_feedback timing indicator can be used to indicate the PUCCH resources.

[0326] Here, the PDSCH-to-HARQ_feedback timing indicator is used to indicate the slot interval between the PDSCH including Msg 4 and the PUCCH including the HARQ-ACK to be sent by the UE, and can indicate a value selected from {0, 1, 2, 3, 4, 5, 6, 7}. For example, when the last slot for receiving the PDSCH including Msg 4 is #n, the PDSCH-to-HARQ_feedback timing indicator indicates the value selected from {0, 1, 2, 3, 4, 5, 6, 7} as the slot interval k, and the UE sends the PUCCH including the HARQ-ACK in slot #n + k. The specific indication method of the PDSCH-to-HARQ_feedback timing indicator is described below.

[0327]

[0328] In addition, the PUCCH resource indicator is used to indicate multiple parameters of the PUCCH resource configuration, and uses the resources of the bit mapping of the dl-DataToUL-ACK sequence (size (1..8)) of the integer (0…15) according to the high-layer parameter PUCCH-Config. The PUCCH resource indicator is 3 bits. When indicating a specific one of two sets each composed of 8 resources through the remaining minimum system information (RMSI), there is a PUCCH resource indicator to configure the PUCCH of one of the corresponding sets.

[0329]

[0330] Similar to the above 4-step RACH procedure, the 2-step RACH procedure may require a method for specifying the PUCCH resource in response to Msg B. Specifically, hereinafter, as a method for indicating the transmission of the PUCCH resource, a method using DCI or MAC (Media Access Control) Msg B can be considered. Since a total of 16 PUCCH resource indices from index 0 to index 15 can be configured as PUCCH resources at a specified timing, when the BS sends Msg B, Msg B should be configured and sent by considering the corresponding PUCCH resource. In addition, in the present disclosure, when the initial PUCCH resource index is specified as n, when the UE is allocated sequentially from index n, if the PUCCH resource index exceeds 15, the UE can be allocated cyclically from index 0 to index n.

[0331] (1) Indicating the PUCCH resource only through DCI

[0332] The corresponding method is a method of specifying the PUCCH resources to be used for HARQ-ACK transmission of a UE by only using the DCI for scheduling Msg B. In this case, the BS can indicate the PDSCH-to-HARQ_feedback timing indicator only through the DCI so that the UE can implicitly calculate the PUCCH resources, or can explicitly indicate the PDSCH-to-HARQ_feedback timing indicator and the initial PUCCH resource index or PUCCH resource indicator through the DCI.

[0333] 1) First, the BS can specify the time slot for transmitting the PUCCH by indicating the time slot interval with the PDSCH-to-HARQ_feedback timing indicator in the DCI field of Msg B. All UEs related to the corresponding Msg B transmit the HARQ-ACK for the reception of Msg B in the time slot specified by the PDSCH-to-HARQ_feedback timing indicator. When doing so, the PUCCH resource index can be mapped one-to-one in sequence to the index order of the MAC sub-header. For example, after detecting its RAPID and UE-ID from the #1 sub-header, the UE transmits the HARQ-ACK through the PUCCH resource index #1. After detecting its RAPID and UE-ID from the #2 sub-header, the UE transmits the HARQ-ACK through the PUCCH resource index #2. Since the UE implicitly knows the PUCCH resource index through its sub-header index, the advantage of this method is that the signaling overhead of the BS is greatly reduced.

[0334] 2) The BS can indicate the time slot for transmitting the PUCCH by using the PDSCH-to-HARQ_feedback timing indicator in the DCI field of Msg B and can configure the initial PUCCH resource index. When doing so, the BS can directly indicate the PUCCH resources by using 4 bits of the PUCCH resource index with values from 0 to 15, or can indirectly indicate the PUCCH resources by using the PUCCH resource indicator in a manner similar to the 4-step RACH procedure.

[0335] In the case of the above method where the BS only indicates the PDSCH-to-HARQ_feedback timing indicator, the PUCCH resource indices #0 to #15 are unconditionally assigned in sequence. However, in the case of this method, the BS designates the initial value of the PUCCH resource index, and the UE receives the assignment of the PUCCH resource index in a one-to-one mapping order according to the index for the MAC sub-header with reference to the index designating the initial value. For example, if the PUCCH resource index #15 is designated in the DCI field, the UE detects its RAPID and UE-ID from the #1 sub-header of Msg B, and then sends HARQ-ACK through the PUCCH resource index #15. The UE detects its RAPID and UE-ID from the #2 sub-header, and then sends HARQ-ACK through the PUCCH resource index #0. The UE detects its RAPID and UE-ID from the #3 sub-header, and then sends HARQ-ACK through the PUCCH resource index #1.

[0336] 3) In the case of the above method 1) or method 2), since all 16 PUCCH resource indices are assigned in sequence, although there are unavailable PUCCH resource indices, the BS cannot indicate the corresponding PUCCH resource indices. To compensate for this problem, bits or bitmaps equivalent to the PUCCH resource indices can be additionally used to indicate the unavailable PUCCH resource indices. That is, the PUCCH resource indicator (PRI) is assigned to the UE in sequence according to the order of the MAC protocol data unit (PDU) in such a way that the PRI is assigned by omitting the part with the value "0" from the additionally indicated bitmap. For example, when the bitmap used to indicate the unavailable PUCCH resource index is "1011111111111111", since the second bit value of the above bitmap is "0", the UE that detects its RAPID and UE-ID from the #2 sub-header of Msg B omits the PUCCH resource index #2 and sends HARQ-ACK through the PUCCH resource index #3. And, the UE that detects its RAPID and UE-ID from the #3 sub-header of Msg B sends HARQ-ACK through the PUCCH resource index #4.

[0337] (2) Indicating the PUCCH resource only through the MAC Msg B

[0338] According to the corresponding method, when sending the MAC Msg B (successful RAR), the BS configures the PDSCH-to-HARQ_feedback timing indicator (3 bits) and the PUCCH resource index (4 bits) or the PUCCH resource indicator (3 bits) for each UE, which is a method of explicitly indicating 6 or 7 bits of information through the Msg B (successful RAR).

[0339] That is, according to this method, when the RAR message received by the UE via Msg B is successRAR, the PUCCH Tx resource can be indicated by the 4-bit PUCCH resource-related indication field in successRAR, and the PUCCH Tx resource can be indicated by the 3-bit PDSCH-to-HARQ feedback timing indication field in successRAR. Although a disadvantage of this method is that the size of Msg B (successRAR) increases when Msg B (successRAR) includes multiple pieces of information, an advantage is that the BS can specify the PUCCH resources of each UE quite flexibly.

[0340] (3) Use both DCI and MAC Msg B to indicate the PUCCH resource

[0341] The corresponding method is a method that utilizes the above methods (1) and (2) by excluding extreme values and utilizes both DCI and MAC Msg B (successRAR). According to transmission parameters of information through which DCI and MAC Msg B (successRAR) are transmitted, such as the PDSCH-to-HARQ_feedback timing indicator and the PUCCH resource index or PUCCH resource indicator, this method can have various embodiments as follows.

[0342] 1) The following can be considered. First, the PDSCH-to-HARQ_feedback timing indicator (3 bits) and the PUCCH resource index (4 bits) or PUCCH resource indicator (3 bits) can be included in DCI, and a 1- or 2-bit PUCCH resource offset value can be transmitted by being included in MAC Msg B (successRAR).

[0343] In this case, since the PDSCH-to-HARQ_feedback timing indicator parameter is basically transmitted by DCI, the signaling overhead increases, which can be compensated in a manner of specifying the PUCCH resource offset value for each UE in MAC Msg B (successRAR). The PUCCH resource index or PUCCH resource indicator is also transmitted by DCI, thus specifying the initial PUCCH resource index in a similar manner to the above method. In this case, in the corresponding method, the offset value indicated by MAC Msg B (successRAR) can be N bits, and the offset can be utilized in the following manner.

[0344] (a) The offset indicated by MAC Msg B (successRAR) can be utilized in a manner of being initially applied to the PRI value of the UE itself. That is, the UE can transmit HARQ-ACK through the PUCCH resource corresponding to the PRI value to which the offset value is applied by referring to its own PRI index.

[0345] The UE receives the assignment of its own PUCCH resource index in sequence by referring to the initial PUCCH resource index specified by DCI according to the sub - header index of the MAC Msg B (successful RAR). If an offset is indicated to the UE by the MAC Msg B (successful RAR), the UE sends HARQ - ACK on the PUCCH resource with an index having an increased or decreased corresponding offset value.

[0346] For example, when the bit indicating the offset is 1, the offset value can become +1 or -1. If the bit indicating the offset is 2, the offset value can indicate the value {+2, +1, -1, -2}, the value {+4, +3, +2, +1} or the value {-4, -3, -2, -1}. If the initial PUCCH resource index is #M, the UE that detects its RAPID and UE - ID from the K - th sub - header receives the assignment of the PUCCH resource index #M + K. If the value of #M + K is greater than 15, the assignment is according to the value of the cyclic shift. By applying the above - mentioned offset value a to it, the UE sends HARQ - ACK on the PUCCH resource with index #M + K + a or #M + K - a.

[0347] (b) The offset indicated by the MAC Msg B (successful RAR) can be utilized by applying it with reference to the position of the previous UE. That is, although the offset accumulated for the previous UE is applied as it is, the PUCCH resource to be used can be determined by additionally applying the offset indicated for the UE's own MAC sub - header.

[0348] For example, when the initial PUCCH resource index is #M, if the first UE that detects its RAPID and UE - ID through the first sub - header receives an indication of an offset equivalent to 3, the corresponding first UE sends HARQ - ACK on the PUCCH resource with index #M + 3. In this case, if the second UE that detects its RAPID and UE - ID through the second sub - header receives an indication of an offset equivalent to 2, the second UE sends HARQ - ACK on the PUCCH resource with index #M + 3+2 in a state where the offset value equivalent to 3 applied to the first UE is cumulatively applied to it.

[0349] 2) As another embodiment, the following can be considered. First, only the PDSCH - to - HARQ_feedback timing indicator (3 bits) is included in the DCI, and each PRI indicating the PUCCH resource indicator (3 bits) is included in the MAC Msg B (successful RAR).

[0350] That is, the corresponding embodiment transmits a common PUCCH Tx time slot via DCI and designates a PUCCH resource index or a PUCCH resource indicator for each UE in a UE-specific manner through a MAC Msg B (successful RAR). According to this embodiment, the signaling overhead may increase more than the above method of indicating an offset in the MAC Msg B (successful RAR), but the flexibility of the PUCCH resource indication by the BS may increase.

[0351] 3) As another embodiment, the following may be considered. First, only the PUCCH resource index (4 bits) or the PUCCH resource indicator (3 bits) is included in the DCI, and each PDSCH-to-HARQ_feedback timing indicator (3 bits) is included in the MAC Msg B (successful RAR).

[0352] The corresponding embodiment is a method of classifying each PUCCH resource by differentiating the time (time slot) configuration of each PUCCH resource. That is, the BS designates a DCI common PUCCH resource index and uses the PUCCH resource according to the corresponding index. Alternatively, when the information of the PUCCH resource index is not included in the DCI, all UEs initially use the PUCCH resource according to the PUCCH resource index #0, and each UE transmits the PUCCH through the corresponding time slot with reference to the time slot timing determined according to the information included in the MAC Msg B (successful RAR).

[0353] Figure 12 FIG. is a diagram showing an operation flow of a user equipment and a base station performing a two-step RACH process according to an embodiment of the present disclosure. The UE and the BS transmit and receive RACH configuration information for performing the two-step RACH process, and information related to the embodiment of the present disclosure (for example, an incremental step and / or an incremental counter, a Tx beam, or a spatial filter, etc.) may also be included in the corresponding information [S1201]. Specifically, the BS may use a synchronization signal block (SSB) such as a master information block (MIB) and a system information block (SIB) and / or RRC signaling to transmit the RACH configuration information.

[0354] In the case where the UE has established a connection state (for example, the UE has received the RACH configuration information or the UE re-accesses the BS that transmits the RACH configuration information), step S1201 may be skipped. Since the corresponding UE has already obtained the RACH configuration information, the corresponding step may be skipped to reduce the processing delay caused by the redundant transmission / reception of the already received RACH configuration information.

[0355] The UE in step S1201 may include Figure 14 the first wireless device 100 or Figure 15 the wireless device 100 / 200, and the BS may includeFigure 14 the second wireless device 200 or Figure 15 the wireless device 100 / 200. That is, the step S1201 in which the UE receives the RACH configuration information from the BS can be implemented by various wireless devices that will be described below in Figures 14 to 17 . For example, when the UE includes Figure 14 the first wireless device 100, Figure 14 the processor 102 can control one or more transceivers 106 and / or one or more memories 104, etc. to receive the RACH configuration information, and one or more transceivers 106 can receive the RACH configuration information from the BS.

[0356] Thereafter, the UE can obtain information (content) about Msg A based on the RACH configuration information received from the BS, and can send Msg A for performing the two-step RACH process by selecting a RACH opportunity (RO) / preamble and a PUSCH opportunity (RO) / PUSCH resource unit (PRU) according to the obtained information [S1203]. Here, the UE can send Msg A based on a configuration related to the Tx power configuration for Msg A in the embodiments of the present disclosure (e.g., incremental step and / or counter, Tx beam or spatial filter, etc.).

[0357] The UE in step S1203 can include Figure 14 the first wireless device 100 or Figure 15 the wireless device 100 / 200, and the BS can include Figure 14 the second wireless device 200 or Figure 15 the wireless device 100 / 200. That is, the step S1203 in which the UE sends Msg A to the BS can be implemented by various wireless devices that will be described below in Figures 14 to 17 . For example, when the UE includes Figure 14 the first wireless device 100, Figure 14 the processor 102 can control one or more transceivers 106 and / or one or more memories 104, etc. to send Msg A, and one or more transceivers 106 can send Msg A to the BS.

[0358] In this case, for an example of the Msg A transmission in step S1203, considering the RO allocated for the four-step RACH process, the RO in the two-step RACH process can be configured as follows: i) configure independent ROs and preambles for each of the two-step RACH process and the four-step RACH process; ii) share the same RO, but configure the preambles separately for each of the two-step RACH process and the four-step RACH process; or iii) the two-step RACH process and the four-step RACH process share the same RO and preamble.

[0359] For another example of Msg A transmission in step S1203, the PRU for the transmission of Msg A PUSCH can be defined considering the PO, DMRS ports, and DMRS sequences, and the PO can be defined as the time - frequency resource for payload transmission. In this case, the PO for the PUSCH of Msg A can be configured separately from the RO or the associated RO can be configured as a relative time and / or frequency position, and one or more POs can be configured within the configuration cycle of the Msg A PUSCH.

[0360] For another example of Msg A transmission in step S1203, the PRACH and PUSCH included in Msg A can be sent in different time slots by time - division multiplexing (TDM), or can be sent in the same time slot. That is to say, the Msg A PUSCH and Msg A PRACH can be sent continuously in the time domain or with a specific gap therebetween.

[0361] For another example of Msg A transmission in step S1203, the PRACH and PUSCH included in Msg A can be sent as follows: i) using the same beam or Tx spatial filter; ii) using the same or different beams or Tx spatial filters according to the determination of the UE; or iii) using the beam or Tx spatial filter configured by the BS.

[0362] For another example of Msg A transmission in step S1203, after Msg A has been sent, the UE can configure a random access response (RAR) window for monitoring Msg B. In this case, in order to record the retry count of the two - step RACH process, the UE can configure a retransmission counter for Msg A, and the maximum value of this counter can be configured by the BS or the network.

[0363] For another example of Msg A transmission in step S1203, the BS can detect the preamble of the Msg A PRACH and process the payload / data of the Msg A PUSCH by decoding. If the BS fails to detect the preamble of the Msg A PRACH, the BS may not transmit any information to the UE.

[0364] As described above, in step S1203 where the UE sends Msg A to the BS, the embodiments of the present disclosure can be appropriately applied. Specifically, the Tx power for Msg A can be configured or indicated based on the method according to the embodiments of the present disclosure described above.

[0365] After sending Msg A, the UE may receive Msg B [S1205]. Here, Msg B may be scheduled by a PDCCH corresponding to DMRS and may be transmitted by a PDSCH corresponding to DMRS. The information (content) included in Msg B may change according to the decoding and processing results of the Msg A PUSCH.

[0366] Specifically, when the BS successfully decodes the Msg A PUSCH, Msg B may include a contention resolution ID (as a successful RAR), such as a UE identifier transmitted by the UE as a common control channel (CCCH) service data unit (SDU). If the BS fails to decode the Msg A PUSCH, Msg B may include a RAPID for retransmitting the Msg A PUSCH and UL grant information as a fallback RAR. When the BS sends a fallback RAR via Msg B, a UE that successfully decodes the RAPID and UL grant included in Msg B may fallback to a 4-step RACH procedure.

[0367] The UE in step S1205 may include Figure 14 the first wireless device 100 of Figure 15 the wireless devices 100 / 200 of Figure 14 the second wireless device 200 of Figure 15 the wireless devices 100 / 200 of. That is, the step S1205 in which the UE receives Msg B from the BS may be implemented by various wireless devices that will be described below in Figures 14 to 17 . For example, when the UE includes Figure 14 the first wireless device 100 of Figure 14 the processor 102 of may control one or more transceivers 106 and / or one or more memories 104, etc. to receive Msg B, and one or more transceivers 106 may receive Msg B from the BS.

[0368] Depending on whether there is decoding and reception of Msg B, the UE may take the same or similar actions as those of a UE that has received Msg 4 after performing the existing 4-step RACH procedure. If the UE successfully receives Msg B within the RAR window, the UE may determine that the 2-step RACH procedure is successful. Alternatively, when the UE receives a fallback RAR, the UE may perform a Msg3 transmission procedure on the 4-step RACH procedure based on the information (e.g., UL grant) included in Msg B.

[0369] On the other hand, when the UE does not receive Msg B within the RAR window, if the retransmission counter is less than the maximum value, the UE may retransmit Msg A to retry the two-step RACH procedure. If the retransmission counter reaches the maximum value, the UE may perform a backoff operation by determining that the two-step RACH procedure has failed. Here, the retransmission of Msg A may mean the retransmission of Msg A P-RACH including the reselection of the preamble and the retransmission of Msg A PUSCH. If the Tx beam or spatial filter for the retransmission of Msg A P-RACH is different from the most recently transmitted Msg A P-RACH, the power ramp counter for the retransmission of Msg A P-RACH may not be incremented.

[0370] The embodiments related to the two-step RACH procedure of the present disclosure described above may also be applicable to the RRC_INACTIVE state, the RRC_CONNECTED state, and the RRC_IDLE state, and may include general medium access control (MAC) procedures. Additionally, the embodiments related to the two-step RACH procedure disclosed above are not applied to system information (SI) requests and / or beam failure recovery (BFR) procedures without exception. Additionally, the operation of re-executing the existing four-step RACH procedure may be considered in the above two-step RACH procedure in consideration of the fallback configuration.

[0371] The various details, functions, procedures, proposals, methods, and / or operation flowcharts described in this document may be applied to various fields (e.g., 5G) that require wireless communication / connection between devices.

[0372] Hereinafter, a detailed description will be given with reference to the accompanying drawings. In the following drawings / description, unless otherwise specified, the same reference numerals may represent the same or corresponding hardware blocks, software blocks, or functional blocks.

[0373] Figure 13 A communication system 1 to which the present disclosure is applied is shown.

[0374] Refer to Figure 13, the communication system 1 applied to the present disclosure includes a wireless device, a BS, and a network. The wireless device is a device that performs communication using a RAT (e.g., 5G NR or LTE), and may be referred to as a communication / radio / 5G device. The wireless device may include (but is not limited to) a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a household appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device / server 400. For example, the vehicle may include a vehicle with wireless communication capabilities, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a household appliance, a digital sign, a vehicle, a robot, etc. The handheld device may include a smartphone, a smart tablet, a wearable device (e.g., a smartwatch or smart glasses), and a computer (e.g., a laptop computer). The household appliance may include a television, a refrigerator, and a washing machine. The IoT device may include sensors and smart meters. For example, the BS and the network may be implemented as wireless devices, and a specific wireless device 200a may operate as a BS / network node for other wireless devices.

[0375] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 or the network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without the intervention of the BS or the network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V / V2X communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0376] Wireless communication / connections 150a, 150b, or 150c can be established between wireless devices 100a to 100f and BS 200 or between BS 200s. The wireless communication / connections can be established via various RATs (e.g., 5G NR) such as UL / DL communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication 150c (e.g., relay and integrated access backhaul (IAB)). Radio signals can be transmitted and received between wireless devices, between a wireless device and a BS, and between BSs via the wireless communication / connections 150a, 150b, and 150c. For example, signals can be transmitted and received on various physical signals via the wireless communication / connections 150a, 150b, and 150c. To this end, at least a part of the various configuration information for configuring processes for transmitting / receiving radio signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes can be executed based on the various proposals of the present disclosure.

[0377] Figure 14 A wireless device applicable to the present disclosure is shown.

[0378] Referring Figure 14 , the first wireless device 100 and the second wireless device 200 can transmit radio signals via various RATs (e.g., LTE and NR). Herein, {the first wireless device 100 and the second wireless device 200} can correspond to Figure 13 {wireless device 100x and BS 200} and / or {wireless device 100x and wireless device 100x}.

[0379] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit radio signals including the first information / signals through the transceiver 106. The processor 102 may receive radio signals including second information / signals through the transceiver 106, and then store the information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including commands for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. Herein, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with the RF unit. In the present disclosure, the wireless device may refer to a communication modem / circuit / chip.

[0380] Specifically, the commands stored in the memory 104 and / or the operations controlled by the processor 102 of the second wireless device 100 according to the embodiments of the present disclosure will be described below.

[0381] Although the following operations are described in the context of the control operations of the processor 102 from the perspective of the processor 102, the software codes for performing these operations may be stored in the memory 104.

[0382] The processor 102 may control the transceiver 106 to transmit a PRACH and a PUSCH in Msg A. The processor 102 may control the transceiver 106 to receive Msg B related to contention resolution. The specific methods for the processor 102 to control the transceiver 106 to transmit Msg A and receive Msg B may be based on the above embodiments.

[0383] Specifically, the commands stored in the memory 204 and / or the operations controlled by the processor 202 of the second wireless device 200 according to the embodiments of the present disclosure will be described below.

[0384] Although the following operations are described in the context of the control operations of the processor 202 from the perspective of the processor 202, the software code for performing these operations may be stored in the memory 204.

[0385] The processor 202 may control the transceiver 206 to receive the PRACH and PUSCH in Msg A. The processor 202 may control the transceiver 206 to send Msg B related to contention resolution. The specific method for the processor 202 to control the transceiver 106 to receive Msg A and send Msg B may be based on the above embodiments.

[0386] The hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by (but not limited to) one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (such as functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors 102 and 202 may generate signals (such as baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (such as baseband signals) from one or more transceivers 106 and 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document.

[0387] One or more processors 102 and 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processor devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. The firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 to be driven by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or instruction sets.

[0388] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories 104 and 204 may be configured by read only memory (ROM), random access memory (RAM), electrically erasable programmable read only memory (EPROM), flash memory, hard disk drive, register, cache memory, computer readable storage medium, and / or a combination thereof. One or more memories 104 and 204 may be located inside and / or outside one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 through various technologies such as wired or wireless connections.

[0389] One or more transceivers 106 and 206 may send user data, control information, and / or radio signals / channels mentioned in the methods and / or operational flowcharts of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 may execute controls such that one or more transceivers 106 and 206 may send user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may control one or more transceivers 106 and 206 to receive user data, control information, or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208 and are configured to send and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert the received radio signals / channels from RF band signals to baseband signals in order to process the received user data, control information, and radio signals / channels using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert the user data, control information, and radio signals / channels processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0390] Figure 15 Another exemplary wireless device applied to the present disclosure is shown. The wireless device may be implemented in various forms according to usage / services (refer to Figure 13 ).

[0391] Refer to Figure 15 , the wireless devices 100 and 200 may correspond to Figure 14 's wireless devices 100 and 200 and may be configured with various elements, components, units / parts, and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may includeFigure 14 one or more processors 102 and 202 and / or one or more memories 104 and 204. For example, the transceiver 114 may include Figure 15 one or more transceivers 106 and 206 and / or one or more antennas 108 and 208. The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140, and controls the overall operation of the wireless device. For example, the control unit 120 may control the electrical / mechanical operations of the wireless device based on programs / codes / commands / information stored in the memory unit 130. The control unit 120 may send the information stored in the memory unit 130 to the outside (e.g., other communication devices) via the wireless / wired interface through the communication unit 110, or store the information received from the outside (e.g., other communication devices) through the communication unit 110 in the memory unit 130 via the wireless / wired interface. Therefore, the specific operations of the control unit 120 according to the present disclosure and the programs / codes / commands / information stored in the memory unit 130 may correspond to Figure 15 at least one operation of the processors 102 and 202 and at least one operation of the memories 104 and 204 shown.

[0392] The additional components 140 may be configured in various ways according to the type of the wireless device. For example, the additional components 140 may include at least one of a power unit / battery, an input / output (I / O) unit, a driving unit, or a computing unit. The wireless device may be implemented as (but not limited to) a robot ( Figure 13 100a), a vehicle ( Figure 13 100b-1 and 100b-2), an XR device ( Figure 13 100c), a handheld device ( Figure 13 100d), a household appliance ( Figure 13 100e), an IoT device ( Figure 13 100f), a digital broadcast terminal, a holographic device, a public safety device, an MTC device, a medical device, a fintech device (or financial machine), a security device, a climate / environment device, an AI server / device ( Figure 13 400), a BS ( Figure 13 200), a network node, etc. According to the usage / service, the wireless device may be used in a mobile or fixed location.

[0393] In Figure 15In [the figure], various elements, components, units / parts, and / or modules in the wireless devices 100 and 200 may all be interconnected through a wired interface, or at least a part of them may be wirelessly interconnected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be wired-connected, and the control unit 120 and the first units (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit / part, and / or module in the wireless devices 100 and 200 may further include one or more elements. For example, the control unit 120 may be configured as a set of one or more processors. For example, the control unit 120 may be configured as a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit, and a memory control processor. In another example, the memory unit 130 may be configured as a RAM, a DRAM, a ROM, a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0394] Now, a detailed description of implementation examples of the devices shown in Figure 15 the figure will be given with reference to the accompanying drawings.

[0395] Figure 16 A handheld device to which the present disclosure is applied is shown. The handheld device may include a smart phone, a smart tablet, a wearable device (e.g., a smart watch or smart glasses), or a portable computer (e.g., a laptop computer, etc.). The handheld device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

[0396] Referring to Figure 16 , the handheld device 100 may include 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 I / O unit 140c. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110 to 130 / 140a to 140c respectively correspond to Figure 15 blocks 110 to 130 / 140 of

[0397] The communication unit 110 can send and receive signals (e.g., data and control signals) to and from other wireless devices or a BS. The control unit 120 can perform various operations by controlling the components of the handheld device 100. The control unit 120 can include an application processor (AP). The memory unit 130 can store data / parameters / programs / codes / commands required to drive the handheld device 100. The memory unit 130 can store input / output data / information. The power supply unit 140a can supply power to the handheld device 100 and includes a wired / wireless charging circuit, a battery, etc. The interface unit 140b can support the connection between the handheld device 100 and other external devices. The interface unit 140b can include various ports (e.g., audio I / O ports and video I / O ports) for connecting to external devices. The I / O unit 140c can input or output video information / signals, audio information / signals, data, and / or information input by the user. The I / O unit 140c can include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and / or a haptic module.

[0398] For example, in the case of data communication, the I / O unit 140c can acquire information / signals (e.g., touch, text, voice, image, or video) input by the user, and the acquired information / signals can be stored in the memory unit 130. The communication unit 110 can convert the information / signals stored in the memory into a radio signal and directly send the radio signal to other wireless devices or to the BS. The communication unit 110 can receive a radio signal from other wireless devices or the BS, and then restore the received radio signal to the original information / signals. The restored information / signals can be stored in the memory unit 130 and output through the I / O unit 140c as various types (e.g., text, voice, image, video, or haptic).

[0399] Figure 17 A vehicle or an autonomous driving vehicle to which the present disclosure is applied is shown. The vehicle or the autonomous driving vehicle can be implemented as a mobile robot, an automobile, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0400] Refer to Figure 17 , the vehicle or the autonomous driving vehicle 100 can include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 can be configured as a part of the communication unit 110. Blocks 110 / 130 / 140a to 140d respectively correspond to Figure 15 blocks 110 / 130 / 140 of

[0401] The communication unit 110 can send signals (e.g., data and control signals) to and receive signals from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 can perform various operations by controlling components of the vehicle or the autonomous driving vehicle 100. The control unit 120 can include an ECU. The driving unit 140a can cause the vehicle or the autonomous driving vehicle 100 to travel on the road. The driving unit 140a can include an engine, a motor, a power system, wheels, brakes, a steering device, etc. The power supply unit 140b can supply power to the vehicle or the autonomous driving vehicle 100 and includes a wired / wireless charging circuit, a battery, etc. The sensor unit 140c can acquire information about the vehicle state, surrounding environment information, user information, etc. The sensor unit 140c can include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / backward 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 140d can implement technologies for maintaining the lane in which the vehicle is traveling, technologies for automatically adjusting the speed (e.g., adaptive cruise control), technologies for autonomously traveling along a determined path, technologies for traveling by automatically setting a path if a destination is set, etc.

[0402] For example, the communication unit 110 can receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d can generate an autonomous driving path and a driving plan based on the obtained data. The control unit 120 can control the driving unit 140a to drive the vehicle or the autonomous driving vehicle 100 along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 can acquire the latest traffic information data from an external server non-periodically or periodically, and acquire surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c can obtain information about the vehicle state and / or surrounding environment information. The autonomous driving unit 140d can update the autonomous driving path and the driving plan based on the newly obtained data / information. The communication unit 110 can transmit information about the vehicle position, the autonomous driving path, and the driving plan to an external server. The external server can use AI technology to predict traffic information data based on the information collected from the vehicle or the autonomous driving vehicle and provide the predicted traffic information data to the vehicle or the autonomous driving vehicle.

[0403] The described embodiments of the present disclosure are combinations of elements and features of the present disclosure. Unless otherwise mentioned, an element or feature may be considered optional. Each element or feature may be practiced without being combined with other elements or features. In addition, embodiments of the present disclosure may be constructed by combining some of the elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some configurations of any one embodiment may be included in another embodiment and may be replaced by corresponding configurations of another embodiment. It will be apparent to those skilled in the art that claims that are not explicitly referenced to each other in the appended claims may be presented as combinations of embodiments of the present disclosure or may be included as new claims by subsequent amendments after the filing of the application.

[0404] Here, the wireless communication technologies implemented in the wireless devices 100 and 200 in this specification may include NarrowBand Internet of Things (NB-IoT) for low-power communication, as well as LTE, NR, and 6G. In this case, for example, the NB-IoT technology may be an example of a Low-Power Wide-Area Network (LPWAN) technology and may be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, but is not limited to the above names. Additionally or alternatively, the wireless communication technologies implemented in the wireless devices 100 and 200 in this specification may perform communication based on the LTE-M technology. In this case, as an example, the LTE-M technology may be an example of an LPWAN technology and may be referred to by various names such as enhanced Machine-Type Communication (eMTC), etc. For example, the LTE-M technology may be implemented by at least one of various standards such as 1) LTE CAT0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE Machine-Type Communication, and / or 7) LTE M, but is not limited to the above names. Additionally or alternatively, considering low-power communication, the wireless communication technologies implemented in the wireless devices 100 and 200 in this specification may include at least one of ZigBee, Bluetooth, and Low-Power Wide-Area Network (LPWAN), but is not limited to the above names. For example, the ZigBee technology may generate a Personal Area Network (PAN) related to small / low-power digital communication based on various specifications such as IEEE 802.15.4, etc., and may be referred to by various names.

[0405] Specific operations described as being performed by the BS may be performed by an upper-layer node of the BS. That is, it is obvious that in a network composed of multiple network nodes including the BS, various operations performed for communicating with the UE may be performed by the BS or a network node other than the BS. The term BS may be replaced by terms such as fixed station, gNode B (gNB), Node B, enhanced Node B (eNode B or eNB), access point, etc.

[0406] Those skilled in the art will understand that, without departing from the spirit and basic characteristics of the present disclosure, the present disclosure can be implemented in other specific ways than those described herein. Therefore, the above-described embodiments are to be construed as illustrative in all respects and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents (rather than the above description), and all changes falling within the meaning and scope of the appended claims are intended to be covered therein.

[0407] Industrial applicability

[0408] The method and device for performing a random access procedure on an unlicensed frequency band are described based on examples applied to the 5th generation New RAT system, but are applicable to various wireless communication systems as well as the 5th generation New RAT system.

Claims

1. A method for a user equipment to perform a random access channel (RACH) procedure on an unlicensed frequency band, the method comprises the following steps: Sending a first message A to a base station via a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH); Based on not receiving a message in response to the first message A from the base station, sending a second message A via the PRACH and the PUSCH; And Receiving a message B related to contention resolution from the base station in response to the second message A, wherein, based on the PRACH and the PUSCH being continuous in the time domain, determining the transmission power of the second message A based on a single power ramping counter configured for message A, and wherein, based on there being a time gap between the PRACH and the PUSCH, determining the transmission power of the second message A based on both a first power ramping counter configured for the PRACH and a second power ramping counter configured for the PUSCH.

2. The method according to claim 1, the method further comprises the following steps: Performing a listen-before-talk (LBT) procedure related to the transmission of the first message.

3. The method according to claim 1, wherein, the transmission of the second message A corresponds to a retransmission of the first message A.

4. The method according to claim 1, wherein, the single power ramping counter increases based on the transmission spatial filter of the PRACH related to the second message A being the same as the transmission spatial filter of the PRACH related to the first message A.

5. The method according to claim 1, wherein, the single power ramping counter is maintained based on the transmission spatial filter of the PRACH related to the second message A being different from the transmission spatial filter of the PRACH related to the first message A.

6. A user equipment for performing a random access channel (RACH) procedure on an unlicensed frequency band, the user equipment comprises: At least one transceiver; At least one processor; And At least one memory, the at least one memory is operatively connected to the at least one processor and stores instructions, the instructions when executed enable the at least one processor to perform specific operations, the specific operations include: Sending a first message A to a base station via a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH); Based on not receiving a message in response to the first message A from the base station, sending a second message A via the PRACH and the PUSCH; and Receiving a message B related to contention resolution from the base station in response to the second message A, wherein, based on the PRACH and the PUSCH being continuous in the time domain, determining the transmission power of the second message A based on a single power ramping counter configured for message A, and Among them, based on there being a time gap between the PRACH and the PUSCH, the transmission power of the second Message A is determined based on both the first power ramp counter configured for the PRACH and the second power ramp counter configured for the PUSCH.

7. The user equipment according to claim 6, wherein, the specific operation further includes: performing a listen-before-talk LBT process related to the transmission of the first message.

8. The user equipment according to claim 6, wherein, the transmission of the second Message A corresponds to a retransmission of the first Message A.

9. The user equipment according to claim 6, wherein, the single power ramp counter increases based on the transmission spatial filter of the PRACH related to the second Message A being the same as the transmission spatial filter of the PRACH related to the first Message A.

10. The user equipment according to claim 6, wherein, the single power ramp counter is maintained based on the transmission spatial filter of the PRACH related to the second Message A being different from the transmission spatial filter of the PRACH related to the first Message A.

11. A computer-readable storage medium storing at least one computer program including instructions that, when executed by at least one processor, enable the at least one processor to perform operations of a user equipment, the operations including: sending a first Message A to a base station via a physical random access channel PRACH and a physical uplink shared channel PUSCH; based on not receiving a message in response to the first Message A from the base station, sending a second Message A via the PRACH and the PUSCH; and in response to receiving a message B related to contention resolution from the base station for the second Message A, wherein, based on the PRACH and the PUSCH being continuous in the time domain, the transmission power of the second Message A is determined based on a single power ramp counter configured for Message A, and wherein, based on there being a time gap between the PRACH and the PUSCH, the transmission power of the second Message A is determined based on both the first power ramp counter configured for the PRACH and the second power ramp counter configured for the PUSCH.

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