Method and apparatus for multicast reception in wireless communication system

Abstract

A method and apparatus for multicast reception in a wireless communication system are provided. The method comprises the following steps: joining an MBS session indicated by a group identifier (ID); when the RRC release message including the pause configuration is received, entering the RRCINACTIVE; receiving a paging message including a group ID and an indicator, the indicator notifying whether multicast reception under RRCINACTIVE is allowed for the MBS session; and informing that the multicast reception under the RRCINACTIVE is not allowed based on the indicator, and initiating an RRC connection recovery process.

Description

Technical Field

[0001] The present disclosure relates to methods and apparatus for multicast reception in a wireless communication system. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology that allows high-speed packet communications. Many solutions have been proposed for the LTE goal, including those aimed at reducing user and supplier costs, improving service quality, and expanding and improving coverage and system capacity. As upper layer requirements, 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of frequency bands, simple structure, open interfaces, and appropriate power consumption of terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work on developing requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components required for successful standardization of new RATs that will meet both urgent market needs and longer-term requirements set forth by the ITU Radiocommunication Sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process in a timely manner. In addition, NR should be able to use any spectrum band up to at least the 100 GHz range that can be used for wireless communications even in the more distant future.

[0004] The goal of NR is to be a single technology framework that addresses all use cases, requirements and deployment scenarios, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable and low latency communications (URLLC), etc. NR should be inherently forward compatible. Summary of the invention

[0005] Technical issues

[0006] When the transmission of the multicast session is resumed, the gNB sends a paging including the multicast session ID to inform the UE in RRC_INACTIVE that the multicast session is resumed.

[0007] If the UE is allowed to receive the multicast session in RRC_INACTIVE, the UE resumes receiving the multicast session in RRC_INACTIVE when receiving the paging message.

[0008] If the UE is not allowed to receive the multicast session in RRC_INACTIVE, the UE initiates the RRC recovery procedure when receiving a paging message for receiving the multicast session after entering RRC_CONNECTED.

[0009] However, when RAN congestion is slightly alleviated, the gNB may wish to transition all UEs receiving multicast sessions in RRC_INACTIVE to RRC_CONNECTED, regardless of whether they are allowed to receive multicast sessions in RRC_INACTIVE, to provide UE feedback-based multicast retransmissions that are only available in RRC_CONNECTED.

[0010] Therefore, there is a need for research on multicast reception in wireless communication systems.

[0011] Solution to the problem

[0012] In one aspect, a method performed by a wireless device in a wireless communication system is provided. The method includes the following steps: joining a multicast and broadcast service (MBS) session indicated by a group identification (ID); entering radio resource control (RRC)_INACTIVE when an RRC release message including a suspension configuration is received; receiving a paging message including the group ID and an indicator, wherein the indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and initiating an RRC connection recovery procedure based on the indicator notifying that the multicast reception under RRC_INACTIVE is not allowed.

[0013] In another aspect, a device for implementing the above method is provided.

[0014] Advantageous Effects of the Invention

[0015] The present disclosure may have various beneficial effects.

[0016] According to some embodiments of the present disclosure, a wireless device may efficiently perform an RRC recovery procedure and save resources.

[0017] For example, by including the new indicator in the paging message, when RAN congestion is alleviated and the network wants all UEs receiving the multicast session to enter RRC_CONNECTED, the network can use group paging to command UEs in RRC_INACTIVE to enter RRC_CONNECTED, although UEs are allowed to receive multicast sessions in RRC_INACTIVE.

[0018] In other words, the paging message may include a new indicator. When RAN congestion is alleviated, the network may want all UEs receiving the multicast session to enter RRC_CONNECTED. In this case, even if the UE is allowed to receive the multicast session in RRC_INACTIVE, the network can use the new indication included in the group paging to command the UE in RRC_INACTIVE to enter RRC_CONNECTED.

[0019] According to some embodiments of the present disclosure, a wireless communication system may provide an efficient solution for multicast reception.

[0020] The beneficial effects that can be obtained by the specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, there may be various technical effects that a person of ordinary skill in the relevant field can understand and / or derive from the present disclosure. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0022] Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0023] Figure 3 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0024] Figure 4 Another example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0025] Figure 5 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0026] Figure 6 and Figure 7 An example of a protocol stack in a 3GPP-based wireless communication system to which an implementation of the present disclosure is applied is shown.

[0027] Figure 8 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0028] Fig. 9 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0029] Fig.10 An example of a bandwidth part (BWP) configuration to which an implementation of the present disclosure is applied is shown.

[0030] Fig.11 Examples of continuous BWP and non-continuous BWP to which the embodiments of the present disclosure are applied are shown.

[0031] Fig.12 An example of bandwidth adaptation to which the implementation of the present disclosure is applied is shown.

[0032] Fig.13 An example of paging is shown.

[0033] Fig.14 An example of a method for multicast reception in a wireless communication system according to some embodiments of the present disclosure is shown.

[0034] Fig.15 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0035] Fig.16 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0036] Fig.17 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0037] Fig.18 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0038] Fig.19 An example of base station (BS) operation for multicast reception in a wireless communication system according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0039] The following techniques, devices and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented by radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented by radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE adopts OFDMA in DL and SC-FDMA in UL. LTE-Advanced (LTE-A) is an evolved version of 3GPP LTE.

[0040] For ease of description, the implementation of the present disclosure is mainly described with respect to a 3GPP-based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP-based wireless communication system, aspects of the present disclosure that are not limited to a 3GPP-based wireless communication system are applicable to other mobile communication systems.

[0041] For terms and techniques not specifically described in the terms and techniques adopted in the present disclosure, reference may be made to wireless communication standard documents issued prior to the present disclosure.

[0042] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B". For example, in the present disclosure, "A, B or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0043] In the present disclosure, a slash ( / ) or a comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0044] In the present disclosure, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, the expression "at least one of A or B" or "at least one of A and / or B" in the present disclosure may be interpreted as being the same as "at least one of A and B".

[0045] In addition, in the present disclosure, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B and / or C" may mean "at least one of A, B, and C".

[0046] In addition, the brackets used in the present disclosure may mean "for example". In detail, when it is shown as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, in the present disclosure, "control information" is not limited to "PDCCH", and "PDCCH" may be proposed as an example of "control information". In addition, even when it is shown as "control information (ie, PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0047] The technical features described separately in one figure in the present disclosure can be implemented separately or simultaneously.

[0048] Although not limited thereto, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein may be applied to various fields requiring wireless communication and / or connection between devices (e.g., 5G).

[0049] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise specified, the same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks and / or functional blocks.

[0050] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0051] exist Figure 1 The 5G usage scenarios shown in the present disclosure are only exemplary, and the technical features of the present disclosure may be applied to Figure 1 Other 5G usage scenarios shown in .

[0052] The three main demand categories for 5G include: (1) enhanced mobile broadband (eMBB) category, (2) massive machine type communication (mMTC) category, and (3) ultra-reliable and low-latency communication (URLLC) category.

[0053] Some use cases may require multiple categories for optimization, and other use cases may focus on only one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable approach.

[0054] eMBB goes far beyond basic mobile Internet access and covers rich two-way work and media and entertainment applications in the cloud and augmented reality. Data is one of the core driving forces of 5G, and in the 5G era, dedicated voice services may not be provided for the first time. In 5G, it is expected that voice will be simply processed as an application using a data connection provided by the communication system. The main reason for increasing business capacity is due to the increase in content size and the increase in the number of applications requiring high data transfer rates. As more and more devices are connected to the Internet, streaming services (audio and video), conversational video, and mobile Internet access will be more widely used. Many of these applications require a connection that is always on in order to push real-time information and alerts to users. Cloud storage and applications are rapidly increasing in mobile communication platforms and can be applied to both work and entertainment. Cloud storage is a special use case that accelerates the growth of uplink data transfer rates. 5G is also used for remote work in the cloud. When using a tactile interface, 5G requires much lower end-to-end latency to maintain a good user experience. Entertainment, such as cloud gaming and video streaming, is another core element that increases the demand for mobile broadband capabilities. Entertainment is essential for smartphones and tablets anywhere including high mobility environments such as trains, vehicles and airplanes. Other use cases are augmented reality for entertainment and information search. In this case, augmented reality requires very low latency and instantaneous data capacity.

[0055] Additionally, one of the most anticipated 5G use cases involves the ability to smoothly connect embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential Internet of Things (IoT) devices will reach 204 billion by 2020. Industrial IoT is one of the categories that performs a major role in enabling smart cities, asset tracking, smart utilities, agriculture, and security infrastructure through 5G.

[0056] URLLC includes remote control and ultra-reliable / available low-latency links over the main infrastructure that will transform new services in industry (such as autonomous vehicles). The level of reliability and latency is necessary to control smart grids, automate industry, enable robotics, and control and adjust drones.

[0057] 5G is a means of providing streams estimated to be hundreds of megabits per second to gigabits per second, and can complement fiber to the home (FTTH) and cable-based broadband (or DOCSIS). Such fast speeds are needed to deliver TV at a resolution of 4K or more (6K, 8K and more), as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games. Specific applications may require special network configurations. For example, for VR games, game companies need to merge core servers into the network operator's edge network servers to minimize latency.

[0058] It is expected that cars, together with many use cases for mobile communications for vehicles, are new and important motivating forces in 5G. For example, the entertainment of passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect high-quality connections, regardless of their location and speed. Another use case in the automotive field is the AR dashboard. The AR dashboard enables the driver to identify objects in the dark in addition to the objects seen from the front window, and displays the distance to the object and the movement of the object by overlapping the information told by the driver. In the future, the wireless module realizes the communication between vehicles, the information exchange between the vehicle and the supporting infrastructure, and the information exchange between the vehicle and other connected devices (e.g., devices accompanied by pedestrians). The safety system guides the alternative route of the behavior so that the driver can drive more safely, thereby reducing the risk of accidents. The next stage will be remotely controlled or self-driving vehicles. This requires very high reliability 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, and the driver will only focus on abnormal traffic that the vehicle cannot recognize. The technical requirements of self-driving vehicles require ultra-low latency and ultra-high reliability, so that traffic safety is increased to a level that cannot be achieved by humans.

[0059] Smart cities and smart homes / buildings, referred to as smart societies, will be embedded in high-density wireless sensor networks. Distributed networks of smart sensors will identify conditions for cost and energy efficient maintenance of cities or homes. Similar configurations can be performed for corresponding homes. All temperature sensors, window and heating controllers, burglar alarms and home appliances are wirelessly connected. Many of these sensors are typically low in data transfer rate, power and cost. However, certain types of devices may require real-time HD video to perform monitoring.

[0060] The consumption and distribution of energy, including heat or gas, is distributed at a higher level, making it necessary to automatically control the distribution sensor network. Smart grids collect information and use digital information and communication technologies to connect sensors to each other, so as to act according to the collected information. Since this information can include the behavior of supply companies and consumers, smart grids can improve the distribution of fuels such as electricity by methods with efficiency, reliability, economic feasibility, production sustainability and automation. Smart grids can also be considered as another sensor network with low latency.

[0061] Mission-critical applications (e.g., e-health) are one of the 5G use cases. The health section includes many applications that can enjoy the benefits of mobile communications. Communication systems can support telemedicine that provides clinical treatment in remote locations. Telemedicine can help reduce barriers to distance and improve access to medical services that are not continuously available in remote rural areas. Telemedicine is also used to perform important treatments and save lives in emergency situations. Wireless sensor networks based on mobile communications can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0062] Wireless and mobile communications are becoming increasingly important in the field of industrial applications. Cabling is expensive in terms of installation and maintenance. Therefore, the possibility of replacing cables with reconfigurable radio links is an attractive opportunity in many industrial fields. However, in order to achieve this replacement, wireless connections need to be established with latency, reliability and capacity similar to cables, and the management of wireless connections needs to be simplified. When it comes to connecting to 5G, low latency and very low error probability are new requirements.

[0063] Logistics and freight tracking are important use cases for mobile communications, which allow inventory and packages to be tracked anywhere using location-based information systems. The use cases for logistics and freight tracking typically require low data rates but require location information with wide range and reliability.

[0064] Reference Figure 1 , the communication system 1 includes wireless devices 100a to 100f, a base station (BS) 200, and a network 300. Figure 1 A 5G network is illustrated as an example of a network of the communication system 1, but implementations of the present disclosure are not limited to the 5G system and may be applied to future communication systems other than the 5G system.

[0065] BS 200 and network 300 may be implemented as wireless devices, and a specific wireless device may operate as a BS / network node relative to other wireless devices.

[0066] The wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G new RAT (NR) or LTE), and may be referred to as communication / wireless / 5G devices. The wireless devices 100a to 100f may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. A vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an AR / 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 smart phone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart tablets, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebooks). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0067] In the present disclosure, the wireless devices 100a to 100f may be referred to as user equipment (UE). For example, the UE may include a cellular phone, a smart phone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a plate-shaped personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with an autonomous driving function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a weather / environmental device, a device related to 5G services, or a device related to the fourth industrial evolution field.

[0068] A UAV may be, for example, an aerial vehicle that is piloted by wireless control signals without a human on board.

[0069] VR devices may include, for example, devices for realizing objects or backgrounds of a virtual world. AR devices may include, for example, devices realized by connecting objects or backgrounds of a virtual world to objects or backgrounds of a real world. MR devices may include, for example, devices realized by merging objects or backgrounds of a virtual world into objects or backgrounds of a real world. Hologram devices may include, for example, devices for realizing a 360-degree stereoscopic image by recording and reproducing stereoscopic information, which uses the interference phenomenon of light generated when two lasers meet, which is called holographic imaging.

[0070] Public safety devices may include, for example, image relay devices or image devices wearable on a user's body.

[0071] MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation, for example. For example, MTC devices and IoT devices may include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0072] The medical device may be, for example, a device for the purpose of diagnosing, treating, alleviating, curing or preventing a disease. For example, the medical device may be a device for the purpose of diagnosing, treating, alleviating or correcting an injury or harm. For example, the medical device may be a device for the purpose of inspecting, replacing or modifying a structure or function. For example, the medical device may be a device for the purpose of regulating pregnancy. For example, the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid or a device for surgery.

[0073] The safety device may be, for example, a device installed to prevent possible danger and maintain safety. For example, the safety device may be a camera, a closed-circuit TV (CCTV), a recorder, or a black box.

[0074] Fintech devices may be devices that can provide financial services such as mobile payments, for example. For example, Fintech devices may include payment devices or point-of-sale (POS) systems.

[0075] Weather / environmental devices may include, for example, devices for monitoring or predicting weather / environmental conditions.

[0076] 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, a 5G (e.g., NR) network, and a super 5G network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without passing through the BS 200 / network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0077] Wireless communication / connection 150a, 150b, and 150c may be established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and BS200 and / or between BS200. In this document, wireless communication / connection may be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)), etc. Wireless devices 100a to 100f and BS200 / wireless devices 100a to 100f may send / receive radio signals to each other through wireless communication / connection 150a, 150b, and 150c. For example, wireless communication / connection 150a, 150b, and 150c may send / receive signals through various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of the resource allocation process can be performed based on various proposals of the present disclosure.

[0078] Here, the radio communication technology implemented in the wireless device in the present disclosure may include narrowband Internet of Things (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of low-power wide area network (LPWAN) technology, which may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the above names. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology, and may be referred to as various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of various specifications such as 1) LTE Cat 0, 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, and may not be limited to the above names. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN considered as low-power communication, and may not be limited to the above names. For example, ZigBee technology may generate a personal area network (PAN) associated with small / low-power digital communication based on various specifications such as IEEE 802.15.4, and may be referred to as various names.

[0079] Figure 2An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0080] Reference Figure 2 , the first wireless device 100 and the second wireless device 200 can transmit / receive radio signals to / from an external device through various RATs (eg, LTE and NR). Figure 2 In the embodiment, {the first wireless device 100 and the second wireless device 200} may correspond to the attached Figure 1 At least one of {wireless devices 100a to 100f and BS200}, {wireless devices 100a to 100f and wireless devices 100a to 100f} and / or {BS200 and BS200}.

[0081] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and 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, suggestions, methods, and / or operational flowcharts described in the present disclosure. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver 106. The processor 102 may receive a radio signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including commands for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts described in the present disclosure. In this document, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0082] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts described in the present disclosure. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including commands for executing part or all of the processes controlled by the processor 202 or for executing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts described in the present disclosure. Herein, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0083] In the following, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). According to the description, function, process, suggestion, method, and / or operation flowchart disclosed in the present disclosure, 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). One or more processors 102 and 202 may generate messages, control information, data, or information according to the description, function, process, suggestion, method, and / or operation flowchart disclosed in the present disclosure. One or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, function, process, suggestion, method, and / or operational flowchart disclosed in the present disclosure, and provide the generated signal to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106 and 206, and obtain the PDU, SDU, message, control information, data, or information according to the description, function, process, suggestion, method, and / or operational flowchart disclosed in the present disclosure.

[0084] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure may be included in one or more processors 102 and 202, or stored in one or more memories 104 and 204, thereby being driven by one or more processors 102 and 202. The descriptions, functions, processes, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software in the form of codes, commands and / or command sets.

[0085] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard 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 of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 by various technologies such as wired or wireless connections.

[0086] One or more transceivers 106 and 206 can send user data, control information and / or radio signals / channels mentioned in the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure to one or more other devices. One or more transceivers 106 and 206 can receive user data, control information and / or radio signals / channels mentioned in the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106 and 206 can 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 can perform control so that one or more transceivers 106 and 206 can send user data, control information or radio signals to one or more other devices. One or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can receive user data, control information or radio signals from one or more other devices.

[0087] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure through one or more antennas 108 and 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0088] One or more transceivers 106 and 206 can convert the received radio signal / channel, etc. from the RF band signal to the baseband signal in order to process the received user data, control information, radio signal / channel, etc. One or more transceivers 106 and 206 can convert the user data, control information, radio signal / channel, etc. processed by one or more processors 102 and 202 from the baseband signal to the RF band signal. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, transceivers 106 and 206 can up-convert the OFDM baseband signal to the carrier frequency through their (analog) oscillators and / or filters under the control of processors 102 and 202, and send the up-converted OFDM signal of the carrier frequency. Transceivers 106 and 206 can receive the OFDM signal of the carrier frequency, and down-convert the OFDM signal to the OFDM baseband signal through their (analog) oscillators and / or filters under the control of processors 102 and 202.

[0089] In an implementation of the present disclosure, a UE may operate as a transmitting device in an uplink (UL) and as a receiving device in a downlink (DL). In an implementation of the present disclosure, a BS may operate as a receiving device in an UL and as a transmitting device in a DL. Hereinafter, for the convenience of description, it is mainly assumed that the first wireless device 100 acts as a UE and the second wireless device 200 acts as a BS. For example, a processor 102 connected to the first wireless device 100, installed on the first wireless device 100, or started in the first wireless device 100 may be configured to perform UE behavior according to an implementation of the present disclosure, or control the transceiver 106 to perform UE behavior according to an implementation of the present disclosure. A processor 202 connected to the second wireless device 200, installed on the second wireless device 200, or started in the second wireless device 200 may be configured to perform BS behavior according to an implementation of the present disclosure, or control the transceiver 206 to perform BS behavior according to an implementation of the present disclosure.

[0090] In the present disclosure, the BS is also referred to as a Node B (NB), an eNodeB (eNB) or a gNB.

[0091] Figure 3 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0092] The wireless device may be implemented in various forms depending on the use case / service (see Figure 1 ).

[0093] Reference Figure 3 , the wireless devices 100 and 200 may correspond to Figure 2 The wireless devices 100 and 200 of the present invention may be configured by 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 an additional component 140. The communication unit 110 may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Figure 2 One or more processors 102 and 202 and / or Figure 2 One or more memories 104 and 204. For example, the transceiver 114 may include Figure 2 One or more transceivers 106 and 206 and / or Figure 2The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional components 140, and controls the overall operation of each of the wireless devices 100 and 200. For example, the control unit 120 may control the electrical / mechanical operation of each of the wireless devices 100 and 200 based on the program / code / command / information stored in the memory unit 130. The control unit 120 may transmit information stored in the memory unit 130 to the outside (e.g., other communication devices) through a wireless / wired interface via the communication unit 110, or store information received from the outside (e.g., other communication devices) through a wireless / wired interface in the memory unit 130 via the communication unit 110.

[0094] The additional component 140 may be configured differently depending on the type of the wireless device 100 and 200. For example, the additional component 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit (e.g., an audio I / O port, a video I / O port), a driving unit, and a computing unit. The wireless device 100 and 200 may be in the form of, but not limited to, a robot ( Figure 1 100a), vehicles ( Figure 1 100b-1 and 100b-2), XR devices ( Figure 1 100c), handheld device ( Figure 1 100d), household appliances ( Figure 1 100e), IoT devices ( Figure 1 100f), digital broadcast terminal, hologram device, public safety device, MTC device, medical device, Fintech device (or financial device), security device, climate / environmental device, AI server / device ( Figure 1 400), BSS( Figure 1 The wireless devices 100 and 200 may be implemented in the form of a wireless device 200 , a network node, etc. The wireless devices 100 and 200 may be used in a mobile or fixed location depending on the usage example / service.

[0095] exist Figure 3In the wireless devices 100 and 200, the entirety of the various elements, components, units / parts and / or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface, or at least a portion thereof may be wirelessly connected 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 connected by wire, and the control unit 120 and the first unit (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit / part and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a group of one or more processors. As an example, the control unit 120 may be configured by a group of communication control processors, application processors (APs), electronic control units (ECUs), graphics processing units, and memory control processors. As another example, the memory unit 130 may be configured by RAM, DRAM, ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0096] Figure 4 Another example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0097] Reference Figure 4 , the wireless devices 100 and 200 may correspond to Figure 2 The wireless devices 100 and 200 may be configured by various elements, components, units / portions and / or modules.

[0098] The first wireless device 100 may include at least one transceiver such as a transceiver 106, and at least one processing chip such as a processing chip 101. The processing chip 101 may include at least one processor such as a processor 102 and at least one memory such as a memory 104. The memory 104 may be operably connected to the processor 102. The memory 104 may store various types of information and / or instructions. The memory 104 may store software code 105, which implements instructions for executing the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure when executed by the processor 102. For example, the software code 105 may implement instructions for executing the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure when executed by the processor 102. For example, the software code 105 may control the processor 102 to execute one or more protocols. For example, the software code 105 may control the processor 102 to execute one or more layers of the radio interface protocol.

[0099] The second wireless device 200 may include at least one transceiver such as the transceiver 206 and at least one processing chip such as the processing chip 201. The processing chip 201 may include at least one processor such as the processor 202 and at least one memory such as the memory 204. The memory 204 may be operably connected to the processor 202. The memory 204 may store various types of information and / or instructions. The memory 204 may store software code 205, which implements instructions for executing the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure when executed by the processor 202. For example, the software code 205 may implement instructions for executing the description, function, process, suggestion, method and / or operation flow chart disclosed in the present disclosure when executed by the processor 202. For example, the software code 205 may control the processor 202 to execute one or more protocols. For example, the software code 205 may control the processor 202 to execute one or more layers of the wireless interface protocol.

[0100] Figure 5 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0101] Reference Figure 5 , UE 100 may correspond to the attached Figure 2 The first wireless device 100 and / or Figure 4 A first wireless device 100 is provided.

[0102] UE 100 includes a processor 102 , a memory 104 , a transceiver 106 , one or more antennas 108 , a power management module 110 , a battery 1112 , a display 114 , a keypad 116 , a subscriber identity module (SIM) card 118 , a speaker 120 , and a microphone 122 .

[0103] The processor 102 may be configured to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor 102 may be an application processor. The processor 102 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). Examples of the processor 102 can be found at MANUFACTURED BY SNAPDRAGON TM Series processors, Manufactured by EXYNOSTM Series processors, A series processors manufactured by Made by HELIO TM Series processors, ATOM manufactured TM series processors or corresponding to the next generation processors.

[0104] The memory 104 is operatively coupled to the processor 102 and stores a variety of information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium, and / or other storage devices. When the embodiment is implemented in software, the techniques described herein may be implemented with modules (e.g., processes, functions, etc.) that execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. The modules may be stored in the memory 104 and executed by the processor 102. The memory 104 may be implemented within the processor 102 or outside the processor 102, in which case the memory 104 may be communicatively coupled to the processor 102 via various means known in the art.

[0105] The transceiver 106 is operatively coupled to the processor 102 and transmits and / or receives radio signals. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include a baseband circuit for processing radio frequency signals. The transceiver 106 controls one or more antennas 108 to transmit and / or receive radio signals.

[0106] The power management module 110 manages power to the processor 102 and / or the transceiver 106. The battery 112 provides power to the power management module 110.

[0107] The display 114 outputs the results processed by the processor 102. The keyboard 116 receives input to be used by the processor 102. The keyboard 116 may be displayed on the display 114.

[0108] The SIM card 118 is an integrated circuit designed to securely store an International Mobile Subscriber Identity (IMSI) number and its associated keys, which are used to identify and authenticate subscribers on mobile telephony devices such as mobile phones and computers. Contact information can also be stored on many SIM cards.

[0109] Speaker 120 outputs sound related results processed by processor 102. Microphone 122 receives sound related input to be used by processor 102.

[0110] Figure 6 and Figure 7 An example of a protocol stack in a 3GPP-based wireless communication system to which an implementation of the present disclosure is applied is shown.

[0111] Specifically, Figure 6 An example of a radio interface user plane protocol stack between a UE and a BS is illustrated, and Figure 7 An example of a radio interface control plane protocol stack between a UE and a BS is illustrated. The control plane refers to a path through which control messages for managing calls made between a UE and a network are transmitted. The user plane refers to a path through which data generated in an application layer (e.g., voice data or Internet packet data) is transmitted. Figure 6 , the user plane protocol stack can be divided into layer 1 (ie, PHY layer) and layer 2. Figure 7 , the control plane protocol stack can be divided into layer 1 (ie, PHY layer), layer 2, layer 3 (eg, RRC layer), and non-access stratum (NAS) layer. Layer 1, layer 2, and layer 3 are called access stratum (AS).

[0112] In the 3GPP LTE system, Layer 2 is separated into the following sublayers: MAC, RLC, and PDCP. In the 3GPP NR system, Layer 2 is separated into the following sublayers: MAC, RLC, PDCP, and SDAP. The PHY layer provides transport channels to the MAC sublayer, the MAC sublayer provides logical channels to the RLC sublayer, the RLC sublayer provides RLC channels to the PDCP sublayer, and the PDCP sublayer provides radio bearers to the SDAP sublayer. The SDAP sublayer provides Quality of Service (QoS) flows to the 5G core network.

[0113] In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing / demultiplexing MAC SDUs belonging to one or different logical channels to / from transport blocks (TBs) delivered to / from the physical layer on the transport channel; scheduling information reporting; error correction through hybrid automatic repeat request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA); priority handling between UEs through dynamic scheduling; priority handling between logical channels of one UE through logical channel prioritization; padding. A single MAC entity can support multiple parameter sets, transmission timings, and cells. The mapping restrictions in the logical channel prioritization control which parameter set(s), cell, and transmission timing can be used by the logical channel.

[0114] MAC provides different kinds of data transmission services. In order to accommodate different kinds of data transmission services, multiple types of logical channels are defined, that is, each logical channel supports the transmission of a specific type of information. Each logical channel type is defined by what type of information is transmitted. Logical channels are divided into two groups: control channels and traffic channels. Control channels are used only for the transmission of control plane information, and traffic channels are used only for the transmission of user plane information. The broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, the paging control channel (PCCH) is a downlink logical channel for transmitting paging information, system information change notifications, and indications of ongoing public warning services (PWS) broadcasts, the common control channel (CCCH) is a logical channel used to send control information between the UE and the network and is used by UEs that do not have an RRC connection with the network, and the dedicated control channel (DCCH) is a point-to-point bidirectional logical channel used by UEs with RRC connections to send dedicated control information between the UE and the network. The dedicated traffic channel (DTCH) is a point-to-point logical channel dedicated to one UE for transmitting user information. DTCH can exist in both the uplink and downlink. In the downlink, there are the following connections between logical channels and transport channels: BCCH can be mapped to the broadcast channel (BCH); BCCH can be mapped to the downlink shared channel (DL-SCH); PCCH can be mapped to the paging channel (PCH); CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In the uplink, there are the following connections between logical channels and transport channels: CCCH can be mapped to the uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0115] The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). The RLC configuration is per logical channel without dependency on parameter sets and / or transmission duration. In 3GPP NR systems, the main services and functions of the RLC sublayer depend on the transmission mode and include: delivery of upper layer PDUs; sequence numbering independent of sequence numbering in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDUs (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).

[0116] In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression using robust header compression (ROHC); transmission of user data; reordering and duplicate detection; in-sequence delivery; PDCP PDU routing (in the case of split bearers); retransmission of PDCP SDU; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status report for RLC AM; duplication of PDCP PDU and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transmission of control plane data; reordering and duplicate detection; in-sequence delivery; duplication of PDCP PDU and duplicate discard indication to lower layers.

[0117] In 3GPP NR system, the main services and functions of SDAP include: mapping between QoS flows and data radio bearers; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

[0118] In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance and release of RRC connection between UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility); QoS management functions; UE measurement reporting and control of reporting; detection and recovery of radio link failures; NAS message transmission from UE to NAS / from NAS to UE.

[0119] Figure 8 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0120] Figure 8The frame structure shown in is merely exemplary, and the number of subframes, the number of time slots, and / or the number of symbols in a frame may vary. In a 3GPP-based wireless communication system, OFDM parameter sets (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) may be configured differently between multiple cells aggregated for one UE. For example, if the UE is configured with different SCSs for cells aggregated for the cell, the (absolute time) duration of time resources (e.g., subframes, time slots, or TTIs) including the same number of symbols may be different among the aggregated cells. In this article, the symbol may include an OFDM symbol (or CP-OFDM symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

[0121] Reference Figure 8 , downlink and uplink transmissions are organized into frames. Each frame has a duration of Tf = 10 ms. Each frame is divided into two half-frames, where each half-frame has a duration of 5 ms. Each half-frame includes 5 sub-frames, where the duration of each sub-frame is T sf is 1ms. Each subframe is divided into time slots, and the number of time slots in a subframe depends on the subcarrier spacing. Each time slot includes 14 or 12 OFDM symbols based on the cyclic prefix (CP). In a normal CP, each time slot includes 14 OFDM symbols, and in an extended CP, each time slot includes 12 OFDM symbols. The parameter set is based on an exponentially scalable subcarrier spacing Δf=2u*15kHz.

[0122] Table 1 shows the subcarrier spacing Δf=2 u *N is the number of OFDM symbols per time slot of 15kHz slot symb , the number of time slots per frame N frame，u slot , and the number of time slots N per subframe for normal CP subframe，u slot .

[0123] [Table 1]

[0124] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot ]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

[0125] Table 2 shows the subcarrier spacing according to Δf=2 u *N is the number of OFDM symbols per time slot of 15kHz slot symb , the number of time slots per frame N frame，u slot , and the number of time slots N per subframe for the extended CP subframe，u slot.

[0126] [Table 2]

[0127] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u s1ot ]]> <![CDATA[N subframe，u slot ]]> 2 12 40 4

[0128] A slot includes a plurality of symbols (e.g., 14 or 12 symbols) in the time domain. For each parameter set (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N indicated by higher layer signaling (e.g., RRC signaling) is allocated. start，u grid To begin, we define N size，u grid，x *N RB sc subcarriers and N subframe，u symb OFDM symbol resource grid, where N size，u grid，x is the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for the downlink and UL for the uplink. N RB se is the number of subcarriers per RB. In 3GPP-based wireless communication systems, N RB sc Typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u size，u grid Given by high-level parameters (e.g., RRC parameters). Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one complex symbol can be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index 1 representing the symbol position relative to a reference point in the time domain. In a 3GPP-based wireless communication system, an RB is defined by 12 consecutive subcarriers in the frequency domain.

[0129] In the 3GPP NR system, RBs are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered upwards from 0 in the frequency domain for subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with "point A" used as a common reference point for the resource block grid. In the 3GPP NR system, PRBs are defined within a bandwidth part (BWP) and are numbered from 0 to N. size BWP，i -1 numbering, where i is the number of the bandwidth part. Physical resource block n in bandwidth part i PRB With common resource block n CRB The relationship between them is as follows: PRB =n CRB +Nsize BWP，i , where N size BWP，i It is a common resource block where the bandwidth part starts relative to CRB 0. A BWP includes multiple consecutive RBs. A carrier can include up to N (e.g., 5) BWPs. A UE can be configured with one or more BWPs on a given component carrier. Only one BWP can be activated at a time among the BWPs configured for a UE. The active BWP defines the operating bandwidth of the UE within the operating bandwidth of the cell.

[0130] The NR frequency band may be defined as two types of frequency ranges, namely, FR1 and FR2. The numerical values ​​of the frequency ranges may vary. For example, the two types of frequency ranges (FR1 and FR2) may be as shown in Table 3 below. For ease of explanation, in the frequency range used in the NR system, FR1 may mean "sub-6 GHz range", FR2 may mean "above 6 GHz range" and may be referred to as millimeter wave (mmW).

[0131] [Table 3]

[0132] Frequency range name Corresponding frequency range Subcarrier spacing FR1 450MHz-6000MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0133] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz, as shown in Table 4 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more included in FR1 may include an unlicensed frequency band. The unlicensed frequency band may be used for various purposes, such as for communication of vehicles (e.g., autonomous driving).

[0134] [Table 4]

[0135] Frequency range name Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0136] In the present disclosure, the term "cell" may refer to a geographical area where one or more nodes provide a communication system or to a radio resource. "Cell" as a geographical area can be understood as a coverage range in which a node can provide services using a carrier, and "cell" as a radio resource (e.g., time-frequency resource) is associated with a bandwidth, which is a frequency range configured by a carrier. A "cell" associated with a radio resource is defined by a combination of downlink resources and uplink resources (e.g., a combination of DL component carriers (CCs) and UL CCs). A cell may be configured only by downlink resources, or may be configured by downlink resources and uplink resources. Since the DL coverage (which is the range in which a node can send a valid signal) and the UL coverage (which is the range in which a node can receive a valid signal from a UE) depend on the carrier that carries the signal, the coverage of a node may be associated with the coverage of a "cell" of a radio resource used by the node. Therefore, the term "cell" may be used to sometimes represent the service coverage of a node, to represent a radio resource at other times, or to represent the range in which a signal using a radio resource can reach with effective strength at other times.

[0137] In CA, two or more CCs are aggregated. The UE can receive or transmit on one or more CCs simultaneously according to its capabilities. CA is supported for both continuous CCs and non-contiguous CCs. When CA is configured, the UE has only one RRC connection with the network. When the RRC connection is established / reestablished / switched, one serving cell provides NAS mobility information, and when the RRC connection is reestablished / switched, one serving cell provides security input. This cell is called the primary cell (PCell). PCell is a cell operating on the primary frequency, where the UE performs an initial connection establishment process or initiates a connection reestablishment process. Depending on the UE capabilities, the secondary cell (SCell) can be configured to form a set of serving cells together with the PCell. SCell is a cell that provides additional radio resources on top of a special cell (PCell). Therefore, the set of configured serving cells for the UE always consists of one PCell and one or more SCells. For dual connection (DC) operation, the term "PCell" refers to the PCell of the primary cell group (MCG) or the primary SCell (PSCell) of the secondary cell group (SCG). SpCell supports PUCCH transmission and contention-based random access and is always activated. MCG is a set of serving cells associated with the master node, which includes SpCell (PCell) and optionally one or more SCells. For UEs configured with DC, SCG is a subset of serving cells associated with the secondary node, which includes PSCell and zero or more SCells. For UEs in RRC_CONNECTED that are not configured with CA / DC, there is only one serving cell consisting of PCell. For UEs in RRC_CONNECTED that are configured with CA / DC, the term "serving cell" is used to refer to the set of cells consisting of SpCell and all SCells. In DC, two MAC entities are configured in the UE: one for MCG and one for SCG.

[0138] Fig. 9 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0139] Reference Fig. 9 , "RB" means radio bearer, and "H" means header. Radio bearers are classified into two groups: DRB for user plane data and SRB for control plane data. MAC PDU is transmitted / received to / from an external device through the PHY layer using radio resources. MAC PDU arrives at the PHY layer in the form of a transport block.

[0140] In the PHY layer, uplink transport channels UL-SCH and RACH are mapped to their physical channels PUSCH and PRACH, respectively, and downlink transport channels DL-SCH, BCH and PCH are mapped to PDSCH, PBCH and PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to physical PUCCH, and downlink control information (DCI) is mapped to PDCCH. MAC PDU related to UL-SCH is sent by UE via PUSCH based on UL grant, and MAC PDU related to DL-SCH is sent by BS via PDSCH based on DL assignment.

[0141] Fig.10 An example of a bandwidth part (BWP) configuration to which an implementation of the present disclosure is applied is shown.

[0142] Reference Fig.10 , a BWP consists of a set of consecutive physical resource blocks (PRBs). The bandwidth (BW) of a BWP cannot exceed the component carrier (CC) BW configured for the UE. The BW of a BWP must be at least as large as one synchronization signal (SS) block BW, but a BWP may or may not contain SS blocks. Each BWP is associated with a specific set of parameters, i.e., subcarrier spacing (SCS) and cyclic prefix (CP) type. Therefore, a BWP is also a means to reconfigure a UE with a specific set of parameters.

[0143] like Fig.10 As shown in the right figure of , the network can configure multiple BWPs to the UE via radio resource control (RRC) signaling, which can overlap in frequency. The granularity of BWP configuration is one PRB. For each serving cell, DL and UL BWPs are separated and independently configured for paired spectrum, and up to four BWPs can be configured for DL ​​and UL respectively. For unpaired spectrum, DL BWP and UL BWP are configured together as a pair, and up to 4 pairs can be configured. Up to 4 UL BWPs can also be configured for supplementary UL (SUL).

[0144] Fig.11 Examples of continuous BWP and non-continuous BWP using implementations of the present disclosure are shown.

[0145] Reference Fig.11 For serving cell measurement, the UE may be configured with multiple BWPs, either continuously or non-continuously. To derive the quality of the serving cell, the UE measures only the configured BWPs, not all BWPs belonging to the serving cell.

[0146] Each configured DL BWP includes at least one control resource set (CORESET) with a UE-specific search space (USS). The USS is a search space where the UE monitors possible receptions of control information destined for the UE. In the primary carrier, at least one of the configured DL BWPs includes a CORESET with a common search space (CSS). The CSS is a search space used for the UE to monitor possible receptions of control information common to all UEs or destined for a specific UE. If the CORESET of the active DL BWP is not configured with a CSS, the UE does not need to monitor it. Note that it is expected that the UE only receives and transmits within the frequency range configured for the active BWP with the associated parameter set. However, there are exceptions. The UE can perform radio resource management (RRM) measurements or send sounding reference signals (SRS) outside its active BWP via measurement gaps.

[0147] Fig.12 An example of bandwidth adaptation to which the implementation of the present disclosure is applied is shown.

[0148] With bandwidth adaptation (BA), the receive and transmit bandwidth of the UE need not be as large as the bandwidth of the cell, and can be adjusted: the width can be commanded to change (e.g., shrink during low activity periods to save power); the position can be moved in the frequency domain (e.g., to increase scheduling flexibility); and the subcarrier spacing can be commanded to change (e.g., to allow different services). A subset of the total cell bandwidth of a cell is called a bandwidth part (BWP), and BA is implemented by configuring the UE with a BWP and telling the UE which of the configured BWPs is the currently active BWP.

[0149] Fig.12 Describes scenarios with 3 different BWP configurations:

[0150] - BWP1, which has a width of 40 MHz and a subcarrier spacing of 15 kHz;

[0151] - BWP2, which has a width of 10 MHz and a subcarrier spacing of 15 kHz;

[0152] -BWP3 has a width of 20MHz and a subcarrier spacing of 60kHz.

[0153] To enable BA on PCell, the gNB configures both UL and DL BWP for the UE. To enable BA on SCell in case of CA, the gNB configures at least DL BWP for the UE (i.e., there may be no DL BWP in UL). For PCell, the BWP for initial access is configured via system information. For SCell, the BWP used after initial activation is configured via dedicated RRC signaling.

[0154] In paired spectrum, DL and UL can switch BWPs independently. In unpaired spectrum, DL and UL switch BWPs simultaneously. Switching between configured BWPs occurs with the help of RRC signaling, DCI, inactivity timer or when random access is initiated. When an inactivity timer is configured for a serving cell, the expiration of the inactivity timer associated with that cell switches the active BWP to the default BWP configured by the network. There can be at most one active BWP per cell, except when the serving cell is configured with SUL, in which case there can be at most one active BWP on each UL carrier.

[0155] In the following, technical features related to the bandwidth part are described. Reference may be made to Section 4.4.5 of 3GPP TS 38.211 v16.1.0.

[0156] A UE may be configured to have up to four bandwidth parts in the downlink, where a single downlink bandwidth part is active at a given time. The UE is not expected to receive PDSCH, PDCCH or CSI-RS (except RRM) outside the active bandwidth part.

[0157] The UE may be configured with up to four bandwidth parts in the uplink, of which a single uplink bandwidth part is active at a given time. If the UE is configured with a supplementary uplink, the UE may additionally be configured with up to four bandwidth parts in the supplementary uplink, of which a single supplementary uplink bandwidth part is active at a given time. The UE shall not send PUSCH or PUCCH outside the active bandwidth part. For an active cell, the UE shall not send SRS outside the active bandwidth part.

[0158] In the following, technical features related to bandwidth part (BWP) operation are described. Reference may be made to Section 5.15 of 3GPP TS 38.321 v16.2.1.

[0159] In particular, BWP operations related to downlink and uplink are described.

[0160] This clause sets out the requirements for the operation of the BWP.

[0161] A serving cell may be configured with one or more BWPs, and the maximum number of BWPs per serving cell may be predetermined.

[0162] BWP switching for the serving cell is used to activate the inactive BWP and deactivate the active BWP at one time. BWP switching is controlled by the PDCCH indicating downlink assignment or uplink grant, by bwp-InactivityTimer, by RRC signaling, or by the MAC entity itself when the random access procedure is started or when a persistent LBT failure on the SpCell is detected. Upon RRC (re)configuration of firstActiveDownlinkBWP-Id and / or firstActiveUplinkBWP-Id for the SpCell or activation of the SCell, the DLBWP and / or UL BWP indicated by firstActiveDownlinkBWP-Id and / or firstActiveUplinkBWP-Id, respectively, are active without receiving a PDCCH indicating downlink assignment or uplink grant. The active BWP for the serving cell is indicated by RRC or PDCCH. For unpaired spectrum, the DL BWP is paired with the UL BWP, and BWP switching is common to both UL and DL.

[0163] For each SCell, the dormant BWP can be configured with dormantBWP-Id through RRC signaling. Entering or leaving the dormant BWP of the SCell is done by BWP switching per SCell or per dormant SCell group based on instructions from the PDCCH. The dormant SCell group configuration is configured by RRC signaling. When a PDCCH indicating leaving the dormant BWP is received, the DL BWP indicated by firstOutsideActiveTimeBWP-Id or by firstWithinActiveTimeBWP-Id is activated. When a PDCCH indicating entering the dormant BWP is received, the DL BWP indicated by dormantBWP-Id is activated. Dormant BWP configuration for SpCell or PUCCH SCell is not supported.

[0164] If the MAC entity receives a PDCCH for BWP switching of the serving cell or dormant SCell group while a random access procedure associated with the serving cell is ongoing in the MAC entity, it is up to the UE implementation to switch the BWP or ignore the PDCCH for BWP switching, unless a PDCCH for BWP switching addressed to the C-RNTI for successful random access procedure completion is received, in which case the UE shall perform a BWP switch to the BWP indicated by the PDCCH. Upon receiving a PDCCH for BWP switching (instead of successful contention resolution), if the MAC entity decides to perform a BWP switch, the MAC entity shall stop the ongoing random access procedure and initiate a random access procedure after performing the BWP switch; if the MAC decides to ignore the PDCCH for BWP switching, the MAC entity shall continue the ongoing random access procedure on the serving cell.

[0165] While a random access procedure associated with a serving cell is being performed in the MAC entity, upon receiving RRC (re)configuration for BWP switching of the serving cell, the MAC entity should stop the ongoing random access procedure and initiate the random access procedure after performing the BWP switching.

[0166] Upon receiving an RRC (re)configuration for BWP handover of a serving cell, any triggered LBT failure in that serving cell is cancelled.

[0167] In the following, technical features related to paging are described. Reference may be made to Section 5.3.2 of 3GPP TS 38.331 v16.4.1.

[0168] Fig.13 An example of paging is shown.

[0169] The purpose of this process is to:

[0170] -Send paging information to UEs in RRC_IDLE or RRC_INACTIVE.

[0171] The network initiates the paging procedure by sending a paging message at the UE's paging occasion. The network can address multiple UEs by including one PagingRecord for each UE in the paging message.

[0172] UE receives paging message

[0173] Upon receiving a paging message, the UE shall:

[0174] 1> If in RRC_IDLE, for each PagingRecord (if any) included in the paging message:

[0175] 2> If the ue-Identity included in the PagingRecord matches the UE identity assigned by the upper layer:

[0176] 3> then forward ue-Identity and accessType (if any) to the upper layer;

[0177] 1> If in RRC_INACTIVE, for each PagingRecord (if any) included in the paging message:

[0178] 2> If the ue-Identity included in the PagingRecord matches the fullI-RNTI stored in the UE:

[0179] 3> If the UE is configured with access identifier 1 by the upper layer:

[0180] 4>Then initiate the RRC connection recovery process, where resumeCause is set to mps-PriorityAccess;

[0181] 3> Otherwise, if the UE is configured with access identifier 2 by the upper layer:

[0182] 4>Then initiate the RRC connection recovery process, where resumeCause is set to mcs-PriorityAccess;

[0183] 3> Otherwise, if the UE is configured by upper layers with one or more access identifiers equal to 11-15:

[0184] 4>Then initiate the RRC connection recovery process, where resumeCause is set to highPriorityAccess;

[0185] 3> Otherwise:

[0186] 4> Initiate the RRC connection recovery process, where resumeCause is set to mt-Access;

[0187] 2> Otherwise, if the ue-Identity included in the PagingRecord matches the UE identity assigned by the upper layer:

[0188] 3> then forward ue-Identity to the upper layer, and forward accessType (if any) to the upper layer;

[0189] 3> Execute actions when entering RRC_IDLE and the release reason is 'other'.

[0190] In the following, an example of paging is described. A paging message is used for notification of one or more UEs. Technical features related to the paging message are as follows.

[0191] Signaling Radio Bearer: N / A

[0192] RLC-SAP:TM

[0193] Logical channel: PCCH

[0194] Direction: Network to UE

[0195] For example, the paging message may include accessType. The accessType may indicate whether the paging message is initiated due to a PDU session from a non-3GPP access.

[0196] In the following, technical features related to short messages are described. Reference may be made to Section 6.5 of 3GPP TS 38.331v16.4.1.

[0197] A short message may be sent on the PDCCH using the P-RNTI with or without an associated paging message using the short message field of DCI format 1_0.

[0198] Table 5 defines the short message. Bit 1 is the most significant bit.

[0199] [Table 5]

[0200]

[0201] Hereinafter, technical features related to group paging (paging for multicast activation notification) are described.

[0202] The UE may receive data for an MBS multicast session only in RRC_CONNECTED state. If a UE joining a multicast session is in RRC_CONNECTED state and when the multicast session starts, the gNB sends an RRC reconfiguration message with the relevant MBS configuration for the multicast session to the UE and a separate session activation notification for the UE is not required.

[0203] The gNB may move the UE to the RRC IDLE / INACTIVE state when there is (temporarily) no data to be sent to the UE for a multicast session. The gNB supporting MBS uses the group notification mechanism to notify UEs in the RRC IDLE / INACTIVE state when a multicast session has been activated by the CN or the gNB has multicast session data to deliver. Upon receiving the group notification, the UE reconnects to the network. The group notification is addressed with the P-RNTI on the PDCCH and the UE monitors the paging channel. The paging message for the group notification contains the MBS session ID which is used to page all UEs in RRC IDLE and RRCINACTIVE states that are joined to the associated MBS multicast session, i.e., UEs are not paged individually. Once a UE leaves a particular multicast session, the UE stops monitoring the group notification related to that multicast session.

[0204] If a UE in RRC IDLE state that joins an MBS multicast session resides on a gNB that does not support MBS, the UE may be notified of the multicast session activation or data availability through CN initiated paging that pages each UE individually. If a UE in RRC INACTIVE state that joins an MBS multicast session resides on a gNB that does not support MBS, the UE may be notified of the data availability through RAN initiated paging.

[0205] For example, group paging is paging for multicast activation notification. For group paging, the following features may be applied.

[0206] - Use PCCH for multicast activation notification (for MBS support nodes).

[0207] - Confirm group paging based on MBS Session ID.

[0208] -Use of paging in traditional PO with PRNTI is the baseline assumption.

[0209] - Confirm that the unicast paging message is extended to include a new paging record list (pagingGroupList) for the group activation notification of the multicast session.

[0210] In addition, when the transmission of the multicast session is resumed, the gNB sends a paging including the multicast session ID to notify the UE in RRC_INACTIVE that the multicast session is resumed.

[0211] If the UE is allowed to receive the multicast session in RRC_INACTIVE, the UE resumes receiving the multicast session in RRC_INACTIVE when receiving the paging message.

[0212] If the UE is not allowed to receive the multicast session in RRC_INACTIVE, the UE initiates the RRC recovery procedure when receiving a paging message for receiving the multicast session after entering RRC_CONNECTED.

[0213] However, when RAN congestion is slightly alleviated, the gNB may wish to transition all UEs receiving multicast sessions in RRC_INACTIVE to RRC_CONNECTED regardless of whether they are allowed to receive multicast sessions in RRC_INACTIVE to provide UE feedback-based multicast retransmissions that are only available in RRC_CONNECTED.

[0214] Therefore, there is a need for research on multicast reception in wireless communication systems.

[0215] Hereinafter, a method for multicast reception in a wireless communication system according to some embodiments of the present disclosure will be described with reference to the following drawings.

[0216] The following figures are created to explain specific embodiments of the present disclosure. The names of specific devices or the names of specific signals / messages / fields shown in the figures are provided by way of example, and therefore the technical features of the present disclosure are not limited to the specific names used in the following figures. In this document, a wireless device may be referred to as a user equipment (UE).

[0217] Fig.14 An example of a method for multicast reception in a wireless communication system according to some embodiments of the present disclosure is shown.

[0218] Specifically, Fig.14 An example of a method performed by a wireless device in a wireless communication system is shown.

[0219] In step S1401, a wireless device may join a multicast and broadcast service (MBS) session indicated by a group identification (ID).

[0220] For example, the group ID may be a Temporary Mobile Group Identity (TMGI).

[0221] In step S1402, the wireless device may enter RRC_INACTIVE upon receiving an RRC release message including a suspension configuration.

[0222] For example, the RRC release message may include an inactive PTM configuration that notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in the serving cell.

[0223] For example, the wireless device may determine that multicast reception under RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message. In other words, when the RRC release message includes the inactive PTM configuration, the wireless device may determine that multicast reception under RRC_INACTIVE is configured.

[0224] In step S1403, the wireless device may receive a paging message including a group ID and an indicator.

[0225] For example, the indicator may inform whether multicast reception in RRC_INACTIVE is allowed for the MBS session.

[0226] For example, the indicator may indicate whether a wireless device with a valid point-to-multipoint (PTM) configuration for the group ID remains in RRC_INACTIVE to receive the MBS multicast session.

[0227] For example, the paging message may include a paging group list. For example, if the network includes a paging group list, it includes the same number of elements and is listed in the same order as in the paging group list. The first element corresponds to the first TMGI in the paging group list. The second element corresponds to the second TMGI in the paging group list, and so on. For example, the indicator may be "inactiveReceptionAllowed". inactiveReceptionAllowed may indicate whether a UE with a valid PTM configuration for a TMGI in the paging group list remains in RRC_INACTIVE to receive the corresponding MBS multicast session.

[0228] In step S1404, based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed, the wireless device may initiate an RRC connection recovery procedure.

[0229] For example, based on the indicator notifying that multicast reception in RRC_INACTIVE is allowed, the wireless device may not initiate the RRC connection recovery procedure and receive the MBS session in RRC_INACTIVE.

[0230] According to some embodiments of the present disclosure, the wireless device may join a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID.

[0231] The wireless device may receive a paging message including (i) a first group ID and a first indicator associated with the first group ID and (ii) a second group ID and a second indicator associated with the second group ID.

[0232] For example, in the first case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0233] In this case, the wireless device may initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0234] For example, in the second case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0235] In this case, the wireless device may receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0236] For example, in the third case, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0237] In this case, the wireless device may initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0238] For example, in the fourth case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

[0239] In this case, the wireless device may receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0240] For example, the wireless device may communicate with at least one of a user device other than the wireless device, a network, or an autonomous vehicle.

[0241] For example, in the RRC connection recovery process, the wireless device may send an RRC recovery request message to the network. The wireless device may receive an RRC recovery message from the wireless device. The wireless device may send an RRC recovery complete message to the wireless device.

[0242] According to some embodiments of the present disclosure, the wireless device may receive a multicast session in RRC_INACTIVE. The wireless device may receive a paging message including an ID of the multicast session and an RRC recovery indicator. The wireless device may determine whether to initiate an RRC connection recovery procedure based on the RRC recovery indicator. The wireless device may initiate an RRC connection recovery procedure based on the determination.

[0243] In the following, technical features related to the RRC recovery indicator in the group notification for the multicast session are described.

[0244] According to the present disclosure, upon receiving a paging message including an ID of a multicast session being received by the UE, the UE in RRC_INACTIVE determines whether to initiate an RRC connection recovery procedure based on an RRC recovery indicator included in the received paging.

[0245] If the RRC recovery indicator in the received paging message indicates that RRC recovery is mandatory, the UE initiates the RRC recovery procedure even though the UE is allowed / can receive the multicast session in RRC_INACTIVE. When RAN congestion is alleviated, the network may set the RRC recovery indicator to "RRC recovery is mandatory".

[0246] If the RRC recovery indicator indicates that RRC recovery is not mandatory, the UE does not initiate the RRC recovery procedure and resumes receiving the multicast session in RRC_INACTIVE.

[0247] If the RRC resumption indicator indicates that RRC resumption is not mandatory, the UE determines to initiate the RRC resumption procedure or resume receiving the multicast session in RRC_INACTIVE without state transition to RRC_CONNECTED based on whether the UE is allowed / able to receive the multicast session in RRC_INACTIVE.

[0248] For example, a UE is allowed to receive a multicast session under RRC_INACTIVE and receive a paging message under RRC_INACTIVE. If the paging message includes a multicast session ID and an RRC recovery indicator indicating that "RRC recovery is not mandatory", the UE receives the multicast session under RRC_INACTIVE without performing an RRC recovery procedure. Another UE is not allowed to receive a multicast session under RRC_INACTIVE. If the paging message includes a multicast session ID and an RRC recovery indicator indicating that "RRC recovery is not mandatory", the UE initiates an RRC recovery procedure.

[0249] When RAN congestion is not alleviated, the network may set the RRC recovery indicator to "RRC recovery is not mandatory".

[0250] When more than one multicast session ID is included in the paging message, the RRC resume indicator may be provided based on the multicast session ID. An RRC resume indicator may be associated with a single multicast session ID or more than one multicast session ID. The UE applies only the RRC resume indicator associated with the multicast session that the UE is receiving / has joined.

[0251] According to some embodiments of the present disclosure, the indicator may inform whether inactive reception is allowed. For example, the indicator may be described as "inactiveReceptionAllowed".

[0252] For example, inactiveReceptionAllowed may indicate whether a UE with valid PTM configuration for the TMGI in the PagingGroupList remains in RRC_INACTIVE to receive the corresponding MBS multicast session.

[0253] For example, when the indicator notifies that inactive reception is allowed, this may mean that RRC resumption is not mandatory. When the indicator notifies that inactive reception is not allowed, this may mean that RRC resumption is mandatory.

[0254] For example, if inactiveReceptionAllowed is included in the paging message, the wireless device may determine that RRC recovery is not mandatory. For example, if inactiveReceptionAllowed is not included in the paging message, the wireless device may determine that RRC recovery is mandatory.

[0255] For example, the UE may perform the following operations:

[0256] When a UE receives a paging message or an L2 U2N remote UE receives a PagingRecord from its connected L2 U2N relay UE, the UE shall:

[0257] 1> If in RRC_INACTIVE and the UE has joined one or more MBS sessions indicated by the TMGI included in pagingGroupList:

[0258] 2> If the UE is not configured with multicast reception in RRC_INACTIVE, or if inactiveReceptionAllowed is not included for at least one of the MBS sessions to which the UE has joined:

[0259] 3> If the ue-Identity included in any PagingRecord (if included in the paging message) does not match the UE identity assigned by the upper layer, then:

[0260] 4> Initiate the RRC connection recovery process according to 5.3.13, where resumeCause is set as follows:

[0261] 5> If the UE is configured with access identification 1 by the upper layer:

[0262] 6> resumeCause is set to mps-PriorityAccess;

[0263] 5> Otherwise, if the UE is configured with access identifier 2 by upper layers:

[0264] 6> resumeCause is set to mcs-PriorityAccess;

[0265] 5> Otherwise, if the UE is configured by upper layers with one or more access identifiers equal to 11-15:

[0266] 6> resumeCause is set to highPriorityAccess;

[0267] 5> Otherwise:

[0268] 6>resumeCause is set to mt-Access;

[0269] 3> Otherwise:

[0270] 4>Forward TMGI to the upper layer.

[0271] Fig.15 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0272] Specifically, Fig.15 An example of a method performed by a UE in a wireless communication system is shown.

[0273] In step S1500 , the UE may receive configuration regarding a multicast session under RRC_CONNECTED.

[0274] The configuration about the multicast session includes at least a g-RNTI for monitoring the multicast session.

[0275] In step S1501, the UE may receive a multicast session in RRC_CONNECTED according to the configuration.

[0276] In step S1502, the UE may receive an RRC release message including an RRC suspension configuration.

[0277] Upon receiving the RRC release message, the UE enters the RRC_INACTIVE state. The RRC release message also includes an indication that the UE may / needs to keep receiving the multicast session after the state transitions to RRC_INACTIVE.

[0278] In step S1503, the UE may receive the multicast session in RRC_INACTIVE.

[0279] In step S1504, the UE may receive a multicast suspension indication from the network.

[0280] When the transmission of the multicast session is suspended, the network notifies the UE thereof so that the UE can suspend monitoring of the multicast session.

[0281] In step S1505, the UE may receive a paging message including the ID of the multicast session. The RRC recovery indicator in the received paging message is set to "RRC recovery is mandatory".

[0282] In step S1506, the UE may initiate an RRC recovery procedure.

[0283] Although the UE is allowed to receive the multicast session in RRC_INACTIVE, since RRC recovery is indicated to be mandatory, the UE initiates RRC recovery.

[0284] According to some embodiments of the present disclosure, upon receiving a paging message including the ID of a multicast session that the UE is receiving / has joined, the UE in RRC_INACTIVE determines whether to initiate an RRC connection recovery procedure based on whether the paging message was received when the multicast session was suspended.

[0285] If the UE receives a paging message including the ID of the multicast session that the UE is receiving when the multicast session is not suspended, the UE initiates the RRC resumption procedure regardless of whether the UE is allowed to receive the multicast session in RRC_INACTIVE.

[0286] If the UE receives a paging message including the ID of the multicast session that the UE is receiving while the multicast session is suspended, the UE receives the multicast session in RRC_INACTIVE without performing RRC recovery.

[0287] Fig.16 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0288] Specifically, Fig.16 A diagram illustrating a method performed by a UE.

[0289] At S1601 , the UE may receive paging including an RRC recovery indicator.

[0290] At S1602 , the UE may check whether the RRC recovery indicator indicates that the RRC recovery is mandatory.

[0291] At S1603, if the RRC recovery indicator indicates that RRC recovery is not mandatory, the UE may check whether the UE is allocated to receive the multicast session in RRC_INACTIVE.

[0292] At S1604, if the RRC resumption indicator indicates that RRC resumption is not mandatory, and if the UE is allocated to receive the multicast session in RRC_INACTIVE, the UE may receive the multicast session in RRC_INACTIVE.

[0293] Otherwise, at S1605, if the RRC recovery indicator indicates that RRC recovery is mandatory, or if the UE is not assigned to receive the multicast session under RRC_INACTIVE, the UE may initiate RRC recovery.

[0294] Fig.17 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0295] Specifically, Fig.17 An example of a method performed by a wireless device in a wireless communication system is shown.

[0296] In step S1701 , the wireless device may join multiple MBS sessions indicated by multiple TMGIs.

[0297] For example, the plurality of MBS sessions may include a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID.

[0298] That is, the wireless device may join a first MBS session indicated by the first group ID and a second MBS session indicated by the second group ID.

[0299] In step S1702, the wireless device may enter RRC inactivity upon receiving an RRC release message including a suspension configuration.

[0300] The RRC release message may include an inactive PTM configuration notifying a PTM configuration for reception of multiple MBS sessions under RRC_INACTIVE in the serving cell.

[0301] For example, the wireless device may determine that multicast reception for multiple MBS sessions under RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message. In other words, when the RRC release message includes the inactive PTM configuration for multiple MBS sessions, the wireless device may determine that multicast reception for multiple MBS sessions under RRC_INACTIVE is configured.

[0302] For example, the RRC release message may include an inactive PTM configuration notifying a PTM configuration for reception of the first MBS session and the second MBS session under RRC_INACTIVE in the serving cell.

[0303] In step S1703 , the wireless device may receive a paging message including (i) a first group ID and a first indicator associated with the first group ID and (ii) a second group ID and a second indicator associated with the second group ID.

[0304] In this example, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0305] In other words, the wireless device can receive a paging message that includes (i) at least two group IDs among multiple group IDs, (ii) at least one indicator notifying that multicast reception under RRC_INACTIVE is allowed for at least one MBS session indicated by at least one group ID, and (iii) at least one indicator notifying that multicast reception under RRC_INACTIVE is not allowed for at least one MBS session indicated by at least one group ID.

[0306] As another example, the wireless device may receive a paging message that includes (i) one or more group IDs among a plurality of group IDs and (ii) one or more indicators associated with the one or more group IDs.

[0307] For example, among the one or more indicators, at least one indicator may notify that multicast reception under RRC_INACTIVE is allowed for at least one MBS session. In addition, among the one or more indicators, at least one indicator may notify that multicast reception under RRC_INACTIVE is not allowed for at least one MBS session.

[0308] In step S1704, the wireless device may initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session based on that multicast reception for at least one MBS session is not allowed.

[0309] That is, when multicast reception for at least one MBS session is not allowed, the wireless device may perform the RRC connection recovery procedure.

[0310] Fig.18 An example of a method for an RRC recovery indicator in a group notification for a multicast session according to some embodiments of the present disclosure is shown.

[0311] Specifically, Fig.18 An example of a method performed by a wireless device in a wireless communication system is shown.

[0312] In step S1801, the wireless device may join multiple MBS sessions indicated by multiple TMGIs.

[0313] For example, the plurality of MBS sessions may include a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID.

[0314] That is, the wireless device may join a first MBS session indicated by the first group ID and a second MBS session indicated by the second group ID.

[0315] In step S1802, the wireless device may enter RRC inactivity upon receiving an RRC release message including a suspension configuration.

[0316] The RRC release message may include an inactive PTM configuration notifying a PTM configuration for reception of multiple MBS sessions under RRC_INACTIVE in the serving cell.

[0317] For example, the RRC release message may include an inactive PTM configuration notifying a PTM configuration for reception of the first MBS session and the second MBS session under RRC_INACTIVE in the serving cell.

[0318] In step S1803 , the wireless device may receive a paging message including (i) a first group ID and a first indicator associated with the first group ID and (ii) a second group ID and a second indicator associated with the second group ID.

[0319] In this example, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session, and the second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0320] In step S1804, based on that multicast reception for at least one MBS session is allowed, the wireless device may receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0321] That is, when multicast reception for at least one MBS session is allowed, the wireless device may not perform the RRC connection recovery procedure.

[0322] Fig.19 An example of base station (BS) operation for multicast reception in a wireless communication system according to some embodiments of the present disclosure is shown.

[0323] In step S1901, the BS may transmit a radio resource control (RRC) release message including a suspension configuration to the wireless device.

[0324] For example, a wireless device may join a Multicast and Broadcast Service (MBS) session indicated by a group identification (ID).

[0325] In step S1902, the BS may transmit a paging message including a group ID and an indicator.

[0326] For example, the indicator may inform whether multicast reception in RRC_INACTIVE is allowed for the MBS session.

[0327] In step S1903, the BS may receive an RRC connection recovery request message from the wireless device based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed.

[0328] For example, the BS may send an RRC recovery message to the wireless device. The BS may receive an RRC recovery complete message from the wireless device.

[0329] Fig.14 , Fig.15 , Fig.16 , Fig.17 , Fig.18 and Fig.19 Some of the detailed steps shown in the examples may not be necessary steps and may be omitted. Fig.14 , Fig.15 , Fig.16 , Fig.17 , Fig.18 and Fig.19 In addition to the steps shown, other steps may be added and the order of the steps may be changed. Some of the above steps may have their own technical meanings.

[0330] In the following, a device for multicast reception in a wireless communication system according to some embodiments of the present disclosure will be described. In this document, the device may be Figure 2 , Figure 3 and Figure 5 A wireless device (100 or 200) in.

[0331] For example, the wireless device may perform the above method. Detailed descriptions overlapping with the above content may be simplified or omitted.

[0332] Reference Figure 5 , the wireless device 100 may include a processor 102 , a memory 104 , and a transceiver 106 .

[0333] According to some embodiments of the present disclosure, the processor 102 may be configured to be operatively coupled with the memory 104 and the transceiver 106 .

[0334] The processor 102 may be adapted to join a multicast and broadcast service (MBS) session indicated by a group identification (ID). The processor 102 may be adapted to enter RRC_INACTIVE upon receiving a radio resource control (RRC) release message including a suspension configuration. The processor 102 may be adapted to control the transceiver 106 to receive a paging message including a group ID and an indicator. For example, the indicator may notify whether multicast reception under RRC_INACTIVE is allowed for the MBS session. Based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed, the processor 102 may be adapted to control the transceiver 106 to initiate an RRC connection recovery process.

[0335] For example, the indicator may indicate whether a wireless device with a valid point-to-multipoint (PTM) configuration for the group ID remains in RRC_INACTIVE to receive the MBS multicast session.

[0336] For example, the group ID may be a Temporary Mobile Group Identity (TMGI).

[0337] For example, the RRC release message may include an inactive PTM configuration that notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in the serving cell.

[0338] For example, the processor 102 may be adapted to determine that the multicast reception in RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message.

[0339] According to some embodiments of the present disclosure, the processor 102 may be adapted to join a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID. The processor 102 may be adapted to control the transceiver 106 to receive a paging message including (i) a first group ID and a first indicator associated with the first group ID and (ii) a second group ID and a second indicator associated with the second group ID.

[0340] In the first case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0341] The processor 102 may then be adapted to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0342] In the second case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0343] Then, the processor 102 may be adapted to control the transceiver 106 to receive the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0344] In the third case, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0345] The processor 102 may then be adapted to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0346] In the fourth case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

[0347] Then, the processor 102 may be adapted to control the transceiver 106 to receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0348] For example, the processor 102 may be adapted to control the transceiver 106 to communicate with at least one of a user device other than a wireless device, a network, or an autonomous vehicle.

[0349] Hereinafter, a processor of a wireless device for multicast reception in a wireless communication system according to some embodiments of the present disclosure will be described.

[0350] The processor may be adapted to control the wireless device to join a multicast and broadcast service (MBS) session indicated by a group identification (ID). The processor may be adapted to control the wireless device to enter RRC_INACTIVE upon receiving a radio resource control (RRC) release message including a suspension configuration. The processor may be adapted to control the wireless device to receive a paging message including a group ID and an indicator. For example, the indicator may notify whether multicast reception under RRC_INACTIVE is allowed for the MBS session. Based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed, the processor may be adapted to control the wireless device to initiate an RRC connection recovery procedure.

[0351] For example, the indicator may indicate whether a wireless device with a valid point-to-multipoint (PTM) configuration for the group ID remains in RRC_INACTIVE to receive the MBS multicast session.

[0352] For example, the group ID may be a Temporary Mobile Group Identity (TMGI).

[0353] For example, the RRC release message may include an inactive PTM configuration that notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in the serving cell.

[0354] For example, the processor may be adapted to control the wireless device to determine that the multicast reception in RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message.

[0355] According to some embodiments of the present disclosure, the processor may be adapted to control the wireless device to join a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID. The processor may be adapted to control the wireless device to receive a paging message including (i) the first group ID and a first indicator associated with the first group ID and (ii) the second group ID and a second indicator associated with the second group ID.

[0356] In the first case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0357] The processor may then be adapted to control the wireless device to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0358] In the second case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0359] Then, the processor may be adapted to control the wireless device to receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0360] In the third case, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0361] The processor may then be adapted to control the wireless device to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0362] In the fourth case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

[0363] Then, the processor may be adapted to control the wireless device to receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0364] For example, the processor may be configured to control the wireless device to communicate with at least one of a user device other than the wireless device, a network, or an autonomous vehicle.

[0365] Hereinafter, a non-transitory computer-readable medium having stored thereon a plurality of instructions for multicast reception in a wireless communication system according to some embodiments of the present disclosure will be described.

[0366] According to some embodiments of the present disclosure, the technical features of the present disclosure may be directly implemented in hardware, in software executed by a processor, or in a combination of the two. For example, a method performed by a wireless device in wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other storage medium.

[0367] Some examples of storage media are coupled to a processor so that the processor can read information from the storage media. In an alternative, the storage medium can be integrated into the processor. The processor and the storage medium can reside in an ASIC. For another example, the processor and the storage medium can reside as discrete components.

[0368] The computer-readable medium may include tangible and non-transitory computer-readable storage media.

[0369] For example, non-transitory computer-readable media may include random access memory (RAM) such as synchronous dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic or optical data storage media, or any other medium that can be used to store instructions or data structures. Non-transitory computer-readable media may also include combinations of the foregoing.

[0370] Additionally, the methods described herein may be implemented at least in part by a computer-readable communication medium that carries or communicates code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0371] According to some embodiments of the present disclosure, a plurality of instructions are stored on a non-transitory computer-readable medium, and the plurality of stored instructions may be executed by a processor of a wireless device.

[0372] The stored multiple instructions may cause the wireless device to join a multicast and broadcast service (MBS) session indicated by a group identification (ID). The stored multiple instructions may cause the wireless device to enter RRC_INACTIVE upon receiving a radio resource control (RRC) release message including a suspension configuration. The stored multiple instructions may cause the wireless device to receive a paging message including a group ID and an indicator. For example, the indicator may notify whether multicast reception under RRC_INACTIVE is allowed for the MBS session. Based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed, the stored multiple instructions may cause the wireless device to initiate an RRC connection recovery procedure.

[0373] For example, the indicator may indicate whether a wireless device with a valid point-to-multipoint (PTM) configuration for the group ID remains in RRC_INACTIVE to receive the MBS multicast session.

[0374] For example, the group ID may be a Temporary Mobile Group Identity (TMGI).

[0375] For example, the RRC release message may include an inactive PTM configuration that notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in the serving cell.

[0376] For example, the stored plurality of instructions may enable the wireless device to determine that multicast reception in RRC_INACTIVE is configured based on an inactive PTM configuration included in the RRC release message.

[0377] According to some embodiments of the present disclosure, the stored multiple instructions may enable the wireless device to join a first MBS session indicated by a first group ID and a second MBS session indicated by a second group ID. The stored multiple instructions may enable the wireless device to receive a paging message including (i) the first group ID and a first indicator associated with the first group ID and (ii) the second group ID and a second indicator associated with the second group ID.

[0378] In the first case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0379] The stored plurality of instructions may then cause the wireless device to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0380] In the second case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0381] The stored plurality of instructions may then cause the wireless device to receive both the first MBS session and the second MBS session in RRC_INACTIVE without performing the RRC connection recovery procedure.

[0382] In the third case, the first indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

[0383] The stored plurality of instructions may then cause the wireless device to initiate an RRC connection recovery procedure to receive both the first MBS session and the second MBS session.

[0384] In the fourth case, the first indicator may notify that multicast reception under RRC_INACTIVE is allowed for the first MBS session. The second indicator may notify that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

[0385] The stored plurality of instructions may then cause the wireless device to receive both the first MBS session and the second MBS session in RRC_IN ACTIVE without performing an RRC connection recovery procedure.

[0386] For example, the stored plurality of instructions may cause the wireless device to communicate with at least one of a user device other than the wireless device, a network, or an autonomous vehicle.

[0387] Hereinafter, a base station (BS) for multicast reception in a wireless communication system according to some embodiments of the present disclosure will be described.

[0388] The BS may include a transceiver, a memory, and a processor operatively coupled to the transceiver and the memory.

[0389] The processor may be adapted to join a multicast and broadcast service (MBS) session indicated by a group identification (ID). The processor may be adapted to enter RRC_INACTIVE upon receiving a radio resource control (RRC) release message including a suspension configuration. The processor may be adapted to receive a paging message including a group ID and an indicator. For example, the indicator may notify whether multicast reception under RRC_INACTIVE is allowed for the MBS session. Based on the indicator notifying that multicast reception under RRC_INACTIVE is not allowed, the processor may be adapted to initiate an RRC connection recovery procedure.

[0390] The present disclosure may have various beneficial effects.

[0391] According to some embodiments of the present disclosure, a wireless device may efficiently perform an RRC recovery procedure and save resources.

[0392] For example, by including the new indicator in the paging message, when RAN congestion is alleviated and the network wants all UEs receiving the multicast session to enter RRC_CONNECTED, the network can use group paging to command UEs in RRC_INACTIVE to enter RRC_CONNECTED, although UEs are allowed to receive multicast sessions in RRC_INACTIVE.

[0393] In other words, the paging message may include a new indicator. When RAN congestion is alleviated, the network may want all UEs receiving the multicast session to enter RRC_CONNECTED. In this case, even if the UE is allowed to receive the multicast session in RRC_INACTIVE, the network can use the new indication included in the group paging to command the UE in RRC_INACTIVE to enter RRC_CONNECTED.

[0394] According to some embodiments of the present disclosure, a wireless communication system may provide an efficient solution for multicast reception.

[0395] The beneficial effects that can be obtained by the specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, there may be various technical effects that can be understood by a person skilled in the relevant art and / or inferred from the present disclosure. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or inferred from the technical features of the present disclosure.

[0396] The claims in this disclosure may be combined in various ways. For example, the technical features in the method claims of this disclosure may be combined to be implemented or performed in a device, and the technical features in the device claims may be combined to be implemented or performed in a method. In addition, the technical features in the method claims and the device claims may be combined to be implemented or performed in a device. In addition, the technical features in the method claims and the device claims may be combined to be implemented or performed in a method. Other implementations are within the scope of the appended claims.

Claims

1. A method performed by a wireless device in a wireless communication system, the method comprising the following steps: Join the multicast and broadcast service MBS session indicated by the group identifier ID; Upon receiving a Radio Resource Control (RRC) release message including a suspension configuration, entering RRC_INACTIVE; receiving a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and Based on the indicator notifying that the multicast reception under RRC_INACTIVE is not allowed, an RRC connection recovery process is initiated.

2. The method according to claim 1, in, The indicator indicates whether the wireless device with a valid point-to-multipoint PTM configuration for the group ID remains in RRC_INACTIVE to receive an MBS multicast session.

3. The method according to claim 1, in, The group ID is a temporary mobile group identity TMGI.

4. The method according to claim 1, wherein: The method further comprises the following steps: joining a first MBS session indicated by the first group ID and a second MBS session indicated by the second group ID; and A paging message is received, the paging message including (i) the first group ID and a first indicator associated with the first group ID and (ii) the second group ID and a second indicator associated with the second group ID.

5. The method according to claim 4, in, The first indicator notifies that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

6. The method according to claim 5, An RRC connection recovery procedure is initiated to receive both the first MBS session and the second MBS session.

7. The method according to claim 5, Without performing the RRC connection recovery procedure, both the first MBS session and the second MBS session are received in RRC_INACTIVE.

8. The method according to claim 4, in, The first indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

9. The method according to claim 8, An RRC connection recovery procedure is initiated to receive both the first MBS session and the second MBS session.

10. The method according to claim 4, in, The first indicator notifies that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

11. The method according to claim 10, Without performing the RRC connection recovery procedure, both the first MBS session and the second MBS session are received in RRC_INACTIVE.

12. The method according to claim 1, in, The RRC release message includes an inactive PTM configuration, and the inactive PTM configuration notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in a serving cell.

13. The method according to claim 12, wherein: The method further comprises the following steps: Determining that the multicast reception in RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message.

14. The method according to claim 1, in, The wireless device communicates with at least one of a user device other than the wireless device, a network, or an autonomous vehicle.

15. A wireless device in a wireless communication system, the wireless device comprising: Transceiver; Memory; as well as at least one processor operatively coupled to the transceiver and the memory and adapted to: Join the multicast and broadcast service MBS session indicated by the group identifier ID; Upon receiving a Radio Resource Control (RRC) release message including a suspension configuration, entering RRC_INACTIVE; receiving a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and Based on the indicator notifying that the multicast reception under RRC_INACTIVE is not allowed, an RRC connection recovery process is initiated.

16. The wireless device according to claim 15, in, The indicator indicates whether the wireless device with a valid point-to-multipoint PTM configuration for the group ID remains in RRC_INACTIVE to receive an MBS multicast session.

17. The wireless device according to claim 15, in, The group ID is a temporary mobile group identity TMGI.

18. The wireless device of claim 15, wherein: The at least one processor is further adapted to: Joining a first MBS session indicated by the first group ID and a second MBS session indicated by the second group ID; and A paging message is received, the paging message including (i) the first group ID and a first indicator associated with the first group ID and (ii) the second group ID and a second indicator associated with the second group ID.

19. The wireless device according to claim 18, in, The first indicator notifies that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

20. The wireless device of claim 19, wherein: The at least one processor is further adapted to: An RRC connection recovery procedure is initiated to receive both the first MBS session and the second MBS session.

21. The wireless device of claim 19, wherein: The at least one processor is further adapted to: Without performing the RRC connection recovery procedure, both the first MBS session and the second MBS session are received in RRC_INACTIVE.

22. The wireless device according to claim 18, in, The first indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is not allowed for the second MBS session.

23. The wireless device of claim 22, wherein: The at least one processor is further adapted to: An RRC connection recovery procedure is initiated to receive both the first MBS session and the second MBS session.

24. The wireless device according to claim 18, in, The first indicator notifies that multicast reception under RRC_INACTIVE is allowed for the first MBS session, and The second indicator notifies that multicast reception under RRC_INACTIVE is allowed for the second MBS session.

25. The wireless device of claim 24, wherein: The at least one processor is further adapted to: Without performing the RRC connection recovery procedure, both the first MBS session and the second MBS session are received in RRC_INACTIVE.

26. The wireless device according to claim 15, in, The RRC release message includes an inactive PTM configuration, and the inactive PTM configuration notifies a PTM configuration for MBS multicast reception under RRC_INACTIVE in a serving cell.

27. The wireless device of claim 26, wherein: The at least one processor is further adapted to: Determining that the multicast reception in RRC_INACTIVE is configured based on the inactive PTM configuration included in the RRC release message.

28. The wireless device of claim 15, wherein: The at least one processor is further adapted to: The transceiver is controlled to communicate with at least one of a user device other than the wireless apparatus, a network, or an autonomous vehicle.

29. A processor for a wireless device in a wireless communication system, wherein: The processor is configured to control the wireless device to perform operations including: Join the multicast and broadcast service MBS session indicated by the group identifier ID; Upon receiving a Radio Resource Control (RRC) release message including a suspension configuration, entering RRC_INACTIVE; receiving a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and Based on the indicator notifying that the multicast reception under RRC_INACTIVE is not allowed, an RRC connection recovery process is initiated.

30. A non-transitory computer readable medium having stored thereon a plurality of instructions that, when executed by a processor of a wireless device, cause the wireless device to perform operations comprising: Join the multicast and broadcast service MBS session indicated by the group identifier ID; Upon receiving a Radio Resource Control (RRC) release message including a suspension configuration, entering RRC_INACTIVE; receiving a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and Based on the indicator notifying that the multicast reception under RRC_INACTIVE is not allowed, an RRC connection recovery process is initiated.

31. A method performed by a base station in a wireless communication system, the method comprising the following steps: sending a radio resource control (RRC) release message including a suspension configuration to the wireless device, wherein the wireless device joins a multicast and broadcast service MBS session indicated by a group identifier ID; sending a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and An RRC connection recovery request message is received from the wireless device based on the indicator notifying that the multicast reception in RRC_INACTIVE is not allowed.

32. A base station in a wireless communication system, the base station comprising: Transceiver; Memory; as well as a processor operatively coupled to the transceiver and the memory, and adapted to: sending a radio resource control (RRC) release message including a suspension configuration to the wireless device, wherein the wireless device joins a multicast and broadcast service MBS session indicated by a group identifier ID; sending a paging message including the group ID and an indicator, The indicator notifies whether multicast reception under RRC_INACTIVE is allowed for the MBS session; and An RRC connection recovery request message is received from the wireless device based on the indicator notifying that the multicast reception in RRC_INACTIVE is not allowed.

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