State transitions based on multicast measurements

Abstract

Methods and apparatus are provided for state transitions based on multicast measurements. A wireless device receives a multicast session from a network while in an inactive state, and initiates a connection resume procedure that transitions from the inactive state to a connected state based on a result of a measurement related to the multicast session satisfying a specific condition.

Description

Technical Field

[0001] The present disclosure relates to state transitions based on multicast measurements. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology for implementing high-speed packet communications. Many solutions have been proposed for the LTE goal, including those aimed at reducing user and provider costs, improving service quality, and expanding and improving coverage and system capacity. 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 as higher-level requirements.

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

[0004] NR targets 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 low latency communications (URLLC), etc. NR should be inherently forward compatible.

[0005] 5G Multicast and Broadcast Services (MBS) is an attempt to combine the world of broadcast services with the voice / data world of cellular mobile communications. Operators want additional revenue streams and are therefore looking at including broadcast services to their offerings. Consumers are looking for additional ways to stay immersed to their mobile screens in a cost-effective manner, and live TV is an obvious extension. Summary of the invention

[0006] Technical Solution

[0007] In one aspect, a method performed by a wireless device adapted to operate in a wireless communication system is provided, the method comprising the steps of receiving a multicast session from a network while in an inactive state, and initiating a connection recovery process for transitioning from the inactive state to a connected state based on results of measurements related to the multicast session satisfying a specific condition.

[0008] In another aspect, a device for implementing the above method is provided.

[0009] Beneficial Effects

[0010] The present disclosure may have various beneficial effects.

[0011] For example, when the reception quality of a multicast session in the RRC_IDLE / INACTIVE state is not good enough, the reception quality of the multicast session can be improved by entering the RRC_CONNECTED state.

[0012] 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 are 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 effects explicitly described herein, but can include various effects that can be understood or derived from the technical features of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0014] Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0015] Figure 3 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0016] Figure 4 and Figure 5 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.

[0017] Figure 6 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0018] Figure 7 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0019] Figure 8 An example of a method performed by a wireless device to which an implementation of the present disclosure is applied is shown.

[0020] Fig. 9 An example of a method executed by a base station to which an implementation of the present disclosure is applied is shown.

[0021] Fig.10 An example of state transition based on PDCP measurement to which an implementation of the present disclosure is applied is shown.

[0022] Fig.11 An example of state transition based on RRC measurement to which an implementation of the present disclosure is applied is shown. DETAILED DESCRIPTION

[0023] The following techniques, devices and systems can be applied to various wireless multiple access systems. Examples of these 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 Rate for GSM Evolution (EDGE). OFDMA can be implemented by radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (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 the downlink (DL) and SC-FDMA in the uplink (UL). The evolutions of 3GPP LTE include LTE Advanced (LTE-A), LTE-A Pro and / or 5G New Radio (NR).

[0024] For ease of description, the embodiments of the present disclosure are 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.

[0025] 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.

[0026] 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".

[0027] 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".

[0028] 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".

[0029] 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".

[0030] 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 "PDDCH" 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".

[0031] The technical features described separately in one figure in the present disclosure can be implemented separately or simultaneously.

[0032] Although not limited to this, 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).

[0033] 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.

[0034] Figure 1 An example of a communication system to which an embodiment of the present disclosure is applied is shown.

[0035] 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 .

[0036] 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.

[0037] 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 the embodiments of the present disclosure are not limited to the 5G system and may be applied to future communication systems other than the 5G system.

[0038] 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.

[0039] The wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G 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 Internet of Things (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 augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television, a 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.

[0040] 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 field of the fourth industrial revolution.

[0041] 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., sidelink 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., sensors) or other wireless devices 100a to 100f.

[0042] 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 BS 200 and / or between BS 200. 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 BS 200 / 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 may be performed based on various proposals of the present disclosure.

[0043] NR supports multiple parameter sets (and / or multiple subcarrier spacing (SCS)) to support various 5G services. For example, if the SCS is 15kHz, wide areas can be supported in traditional cellular bands, and if the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidths can be supported. If the SCS is 60kHz or higher, bandwidths greater than 24.25GHz can be supported to overcome phase noise.

[0044] The NR frequency band may be defined as two types of frequency ranges, namely, frequency range 1 (FR1) and frequency range 2 (FR2). The numerical values ​​of the frequency ranges may be changed. For example, the two types of frequency ranges (FR1 and FR2) may be as shown in Table 1 below. For ease of explanation, in the frequency range used in the NR system, FR1 may mean "a range below 6 GHz", FR2 may mean "a range above 6 GHz", and may be referred to as millimeter wave (mmW).

[0045] [Table 1]

[0046] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz–6000MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0047] As mentioned above, the value of the frequency range of the NR system can be changed. For example, FR1 may include 410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above included in FR1 may include an unlicensed frequency band. The unlicensed frequency band can be used for various purposes, for example, communication of vehicles (e.g., autonomous driving).

[0048] [Table 2]

[0049] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz–7125MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0050] Here, the radio communication technology implemented in the wireless device in the present disclosure may include narrowband IoT (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of a 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 names mentioned above. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may be based on LTE-M technology for communication. For example, LTE-M technology may be an example of LPWAN technology and is referred to as various names such as enhanced MTC (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 considering low-power communication, and may not be limited to the names mentioned above. 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.

[0051] Figure 2 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0052] exist Figure 2 In the embodiment, the first wireless device 100 and / or the second wireless device 200 may be implemented in various forms according to the usage / service. For example, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1At 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}. The first wireless device 100 and / or the second wireless device 200 may be configured by various elements, devices / components and / or modules.

[0053] The first wireless device 100 may include at least one transceiver, such as the transceiver 106 ; at least one processing chip, such as the processing chip 101 ; and / or one or more antennas 108 .

[0054] The processing chip 101 may include at least one processor, such as the processor 102, and at least one memory, such as the memory 104. Additionally and / or alternatively, the memory 104 may be placed outside the processing chip 101.

[0055] The processor 102 may control the memory 104 and / or the transceiver 106 and may be adapted to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts described in the present disclosure. For example, the processor 102 may process the information in the memory 104 to generate a first information / signal, and then transmit a radio signal including the first information / signal through the transceiver 106. The processor 102 may receive a radio signal including a second information / signal through the transceiver 106 and then store information obtained by processing the second information / signal in the memory 104.

[0056] 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 firmware and / or software code 105 that implements codes, commands, and / or sets of commands that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 105 may control the processor 102 to execute one or more protocols. For example, the firmware and / or software code 105 may control the processor 102 to execute one or more layers of a radio interface protocol.

[0057] 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 send 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.

[0058] The second wireless device 200 may include at least one transceiver, such as the transceiver 206 ; at least one processing chip, such as the processing chip 201 ; and / or one or more antennas 208 .

[0059] 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. Additionally and / or alternatively, the memory 204 may be placed outside the processing chip 201.

[0060] The processor 202 may control the memory 204 and / or the transceiver 206 and may be adapted to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts 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.

[0061] 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 firmware and / or software code 205 that implements codes, commands, and / or sets of commands that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 205 may control the processor 202 to execute one or more protocols. For example, the firmware and / or software code 205 may control the processor 202 to execute one or more layers of a radio interface protocol.

[0062] In this document, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and send 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.

[0063] 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 physical (PHY), layer, medium access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP) layer). One or more processors 102 and 202 may generate one or more protocol data units (PDUs), one or more service data units (SDUs), messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operation flow charts disclosed in the present disclosure. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure.

[0064] 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. For example, one or more processors 102 and 202 may be configured by a collection of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphics processing unit (GPU), and a memory control processor. 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.

[0065] The one or more memories 104 and 204 may be configured by random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EPROM), flash memory, volatile memory and non-volatile memory, hard disk drive, register, cache memory, computer-readable storage medium and / or a combination thereof. The one or more memories 104 and 204 may be located inside and / or outside the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connections.

[0066] One or more transceivers 106 and 206 may 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 may 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 may be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may send user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

[0067] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208. Additionally and / or alternatively, one or more transceivers 106 and 206 may include one or more antennas 108 and 208. One or more transceivers 106 and 206 may be adapted 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. In the present disclosure, one or more antennas 108 and 208 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0068] The one or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc. from RF band signals to baseband signals so as to process the received user data, control information, radio signals / channels, etc. using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals / channels, etc. processed using the one or more processors 102 and 202 from baseband signals to RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, the one or more transceivers 106 and 206 may up-convert OFDM baseband signals to OFDM signals through their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The one or more transceivers 106 and 206 may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal through their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 .

[0069] Although in Figure 2 140, but the wireless devices 100 and 200 may further include additional components. The additional components 140 may be configured differently depending on the type of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a drive device, and a computing device. The additional components 140 may be coupled to the one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0070] In an embodiment of the present disclosure, a UE may operate as a transmitting device in UL and as a receiving device in DL. In an embodiment of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. In the following, for the convenience of description, it is mainly assumed that the first wireless device 100 is a UE and the second wireless device 200 is a BS. For example, a processor 102 connected to, installed on, or started in the first wireless device 100 may be suitable for executing a UE behavior according to an embodiment of the present disclosure or controlling a transceiver 106 to execute a UE behavior according to an embodiment of the present disclosure. A processor 202 connected to, installed on, or started in the second wireless device 200 may be suitable for executing a BS behavior according to an embodiment of the present disclosure or controlling a transceiver 206 to execute a BS behavior according to an embodiment of the present disclosure.

[0071] In this disclosure, a BS is also referred to as a Node B (NB), an eNode B (eNB), or a gNB.

[0072] Figure 3 An example of a UE to which an embodiment of the present disclosure is applied is shown.

[0073] refer to Figure 3 , UE 100 may correspond to Figure 2 A first wireless device 100 is provided.

[0074] UE 100 includes a processor 102 , a memory 104 , a transceiver 106 , one or more antennas 108 , a power management module 141 , a battery 142 , a display 143 , a keypad 144 , a subscriber identity module (SIM) card 145 , a speaker 146 , and a microphone 147 .

[0075] 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 DSP, a CPU, a GPU, a modem (modulator and demodulator). Examples of the processor 102 may be found at MANUFACTURED BY SNAPDRAGON TM Series processors, Manufactured by EXYNOS TM Series processors, A series processors manufactured by Made by HELIO TM Series processors, ATOM manufactured TM series processors or the corresponding next-generation processors.

[0076] The memory 104 is operably 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 technology described herein can 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 can be stored in the memory 104 and executed by the processor 102. The memory 104 can be implemented within the processor 102 or outside the processor 102, in which case the memory 104 can be communicatively coupled to the processor 102 via various means known in the art.

[0077] The transceiver 106 is operably 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.

[0078] The power management module 141 manages the power of the processor 102 and / or the transceiver 106. The battery 142 supplies power to the power management module 141.

[0079] The display 143 outputs the result processed by the processor 102. The keyboard 144 receives input to be used by the processor 102. The keyboard 144 may be shown on the display 143.

[0080] The SIM card 145 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.

[0081] The speaker 146 outputs sound related results processed by the processor 102. The microphone 147 receives sound related input to be used by the processor 102.

[0082] Figure 4 and Figure 5 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.

[0083] Specifically, Figure 4An example of a radio interface user plane protocol stack between a UE and a BS is illustrated, and Figure 5 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 4 , the user plane protocol stack can be divided into layer 1 (ie, PHY layer) and layer 2. Figure 5 , 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).

[0084] 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.

[0085] 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) on transport channels for delivery to / from the physical layer; 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.

[0086] 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.

[0087] 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).

[0088] 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 reporting for RLC AM; PDCP PDU duplication 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; PDCP PDU duplication and duplicate discard indication to lower layers.

[0089] 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.

[0090] 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 the 5G core network (5GC) or the next generation radio access network (NG-RAN); establishment, maintenance and release of the RRC connection between the UE and the 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.

[0091] Figure 6 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0092] Figure 6The 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., 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 a cyclic prefix (CP)-OFDM symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

[0093] Reference Figure 6 , downlink and uplink transmissions are organized into frames. Each frame has T f = 10ms duration. Each frame is divided into two half-frames, where each half-frame has a duration of 5ms. Each half-frame includes 5 sub-frames, where the duration of each sub-frame is T sf is 1ms. Each subframe is divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on the CP. In a normal CP, each slot includes 14 OFDM symbols, and in an extended CP, each slot includes 12 OFDM symbols. The parameter set is based on an exponentially scalable subcarrier spacing Δf=2 u *15kHz.

[0094] Table 3 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 .

[0095] [Table 3]

[0096] 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

[0097] Table 4 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 slots N per subframe for the extended CPsubframe,u slot .

[0098] [Table 4]

[0099] u <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 2 12 40 4

[0100] 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 sc 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.

[0101] In 3GPP-based wireless communication systems, an RB is defined by 12 consecutive subcarriers in the frequency domain. In 3GPP NR systems, 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 3GPP NR systems, PRBs are defined within bandwidth parts (BWPs) 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 is as follows:PRB =n CRB +N size 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.

[0102] 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.

[0103] 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 physical uplink control channel (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.

[0104] Figure 7 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0105] Reference Figure 7 , "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.

[0106] In the PHY layer, the uplink transport channel UL-SCH and the random access channel (RACH) are mapped to their physical channels, the physical uplink shared channel (PUSCH) and the physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to the physical downlink shared channel (PDSCH), the physical broadcast channel (PBCH) and the PDSCH, respectively. In the PHY layer, the uplink control information (UCI) is mapped to the physical PUCCH, and the downlink control information (DCI) is mapped to the physical downlink control channel (PDCCH). The MAC PDU related to the UL-SCH is sent by the UE via the PUSCH based on the UL grant, and the MAC PDU related to the DL-SCH is sent by the BS via the PDSCH based on the DL assignment.

[0107] The NR system enables resource-efficient delivery of multicast / broadcast services (MBS).

[0108] For broadcast communication services, the same service and the same specific content data are provided to all UEs in a geographic area at the same time (i.e., all UEs in the broadcast service area are authorized to receive the data). Broadcast communication services are delivered to UEs using broadcast sessions. UEs can receive broadcast communication services in RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states.

[0109] For multicast communication services, the same service and the same specific content data are provided to a dedicated set of UEs at the same time (i.e., not all UEs in the multicast service area are authorized to receive data). Multicast communication services are delivered to UEs using multicast sessions. UEs can receive multicast communication services using mechanisms such as point-to-point (PTP) and / or point-to-multipoint (PTM) delivery in the RRC_CONNECTED state. HARQ feedback / retransmission can be applied to PTP transmissions and PTM transmissions.

[0110] Describe the multicast service in detail.

[0111] There are two delivery modes:

[0112] -5GC shares MBS service delivery;

[0113] -5GC individual MBS service delivery.

[0114] If the gNB node supports MBS, the network can use 5GC to share MBS service delivery. In this case, when the first UE joins the multicast session, an MBS session resource context for the multicast session is established in the gNB.

[0115] For MBS shared delivery mode, shared NG-U resources are used to provide MBS user data to the gNB. The gNB node initiates a multicast distribution establishment procedure towards the 5GC to allocate shared NG-U resources for a multicast session. In case multiple MBS session areas are associated with an MBS session for location-dependent MBS services, multiple NG-U shared resources are established for the same multicast session per MBS area session ID served by the gNB.

[0116] Shared NG-U resources use one of the following transport options:

[0117] -Unicast transmission;

[0118] -Multicast transmission.

[0119] For 5GC shared MBS service delivery, the MBS session resources include one or more MBS radio bearers (MRBs). If data loss minimization is applied for a given MRB, synchronization of PDCP SN allocation is applied by one or a combination of the following methods:

[0120] - derive the PDCP SN with the help of the DL MBS QFI sequence number provided on the NG-U;

[0121] - A shared NG-U terminal is deployed at the NG-RAN and shared among the gNBs, which includes a common entity for assigning PDCP SN.

[0122] Synchronization of MBS QoS flows to MRB mapping within the gNB is achieved with the help of network implementation.

[0123] If the PDCP SN is derived from the DL MBS QFI sequence number provided on NG-U and only one QoS flow is mapped to an MRB, the gNB may set the PDCP SN of the PDCP PDU to the value of the DL MBS QFI sequence number provided with the packet received on NG-U. If the PDCP SN is derived from the DL MBS QFI sequence number provided on NG-U and multiple QoS flows are mapped to an MRB, the gNB may derive the PDCP SN of the PDCP PDU from the sum of the DL MBS QFI sequence numbers of the QoS flows mapped to that MRB.

[0124] A 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.

[0125] 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. A gNB supporting MBS uses a group notification mechanism to notify UEs in the RRC Idle / Inactive state when a multicast session has been activated by the Core Network (CN) or the gNB has multicast session data to be delivered. Upon receiving the group notification, the UE reconnects to the network. The group notification is addressed with the Paging Radio Network Temporary Identity (P-RNTI) on the PDCCH and the paging channel is monitored by the UE. The paging message for the group notification contains the MBS session ID, which is used to page all UEs in RRC_IDLE and RRC_INACTIVE states that are joined to the associated MBS multicast session, i.e., the UEs are not paged individually. The UE stops monitoring the group notification related to a specific multicast session once the UE leaves that multicast session.

[0126] If a UE in RRC_IDLE state that is participating in an MBS multicast session is residing 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, where the CN pages each UE individually. If a UE in RRC_INACTIVE state that is participating in an MBS multicast session is residing on a gNB that does not support MBS, the UE may be notified of the data availability through RAN initiated paging.

[0127] The gNB may use the RRC reconfiguration message to configure or reconfigure a multicast MRB, e.g., to add / release / modify the RLC entity of an MRB. To minimize data loss due to MRB reconfiguration, the gNB may configure the UE to send a PDCP status report during reconfiguration that results in a change of MRB type.

[0128] For multicast services, the gNB can use the following methods to deliver multicast MBS data packets:

[0129] -PTP transmission: The gNB delivers a separate copy of the MBS data packet to each UE independently, i.e., the gNB uses a UE-specific PDCCH with a cyclic redundancy check (CRC) scrambled by a UE-specific RNTI (e.g., cell RNTI (C-RNTI)) to schedule a UE-specific PDSCH scrambled with the same UE-specific RNTI.

[0130] -PTM transmission: The gNB delivers a single copy of the MBS data packet to a set of UEs, e.g., the gNB uses a group-common PDCCH with a CRC scrambled by the group-common RNTI to schedule a group-common PDSCH scrambled with the same group-common RNTI.

[0131] If a UE is configured with both PTM and PTP transmissions, the gNB dynamically decides based on the protocol stack whether to deliver multicast data over PTM branches and / or PTP branches for a given UE based on information such as MBS session QoS requirements, number of joined UEs, UE individual feedback on reception quality, and other criteria. The same QoS requirements apply regardless of the decision.

[0132] It has been studied that a UE in RRC_IDLE state and / or RRC_INACTIVE state can receive a multicast session. A UE in RRC_IDLE state and / or RRC_INACTIVE state can receive a multicast session on a BWP dedicated multicast (ie, a multicast BWP). The multicast BWP may be referred to as a multicast common frequency resource (CFR).

[0133] The multicast CFR may not overlap with the initial BWP. The initial BWP is used to perform the initial access process. The UE may perform cell reselection based on the measurement of the initial BWP. That is, the UE may measure the initial BWP of the cell and compare the measurement results of the initial BWP of each cell. If the measurement result of the initial BWP of a specific cell meets a specific condition, the UE may reselect the specific cell.

[0134] If the UE performs cell reselection based on the measurement of the initial BWP, the reception quality of the multicast session sent in the multicast CFR cannot be guaranteed. If the reception quality of the multicast session in the RRC_INACTIVE state and / or the RRC / inactive state is not satisfactory (for example, not good enough), the UE needs to enter the RRC_CONNECTED state to receive the multicast session using HARQ retransmission. That is, if the reception quality of the multicast session is poor, the UE needs to be able to transition to the RRC_CONNECTED state to receive the multicast session based on HARQ feedback. Therefore, a solution is proposed that specifies the ability for the UE to restore the RRC connection when the reception quality of the multicast session in the RRC_INACTIVE state is not satisfactory.

[0135] According to an implementation of the present disclosure, for a UE that is receiving, has joined, or wants to receive a multicast session, if a measurement result of the multicast session meets a specific condition, the UE may initiate an RRC connection establishment process and / or an RRC connection recovery process.

[0136] The following figures are created to explain the 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, so the technical features of the present disclosure are not limited to the specific names used in the following figures.

[0137] Figure 8An example of a method performed by a wireless device to which an implementation of the present disclosure is applied is shown.

[0138] At step S800 , the method includes transitioning from a connected state (eg, RRC_CONNECTED state) to an inactive state (eg, RRC_INACTIVE state).

[0139] At step S810 , the method includes receiving a multicast session from a network while in an inactive state.

[0140] At step S820, the method includes performing measurements related to the multicast session. That is, if the wireless device is receiving, has joined, or wants to receive a multicast session, the wireless device may perform multicast measurements.

[0141] In some implementations, the measurement related to the multicast session may be a PDCP measurement including counting the number of lost PDCP SDUs or PDUs for an MRB associated with the multicast session. That is, for an MRB associated with a multicast session that the wireless device is receiving, has joined, or wants to receive, the wireless device (the PDCP entity) may detect and count the lost PDCP SDUs or PDUs.

[0142] In some implementations, a measurement window may be configured for PDCP measurement. The number of lost PDCP SDUs or PDUs may be counted within the measurement window. The measurement window may be configured by the network.

[0143] In some implementations, the measurements related to the multicast session may be radio resource management (RRM) measurements that include measurements of at least one of an SSB or a CSI-RS associated with a multicast CFR of the receiving multicast session. That is, the wireless device may perform SSB / CSI-RS based measurements based on the SSB / CSI-RS associated with the multicast CFR of the multicast session that the receiving wireless device is receiving, has joined, or wants to receive.

[0144] In some implementations, for RRM measurements, a configuration for at least one of an SSB or CSI-RS associated with a multicast CFR may be provided by the network for an SSB / CSI-RS associated with a multicast CFR and / or a multicast session. For example, the configuration may include an SSB measurement timing configuration (SMTC). An SSB associated with a multicast CFR may be received within or outside the multicast CFR.

[0145] At step S830, the method includes initiating a connection recovery process of transitioning from an inactive state (e.g., RRC_INACTIVE state) to a connected state (e.g., RRC_CONNECTED state) based on the result of the measurement related to the multicast session satisfying a specific condition. That is, if the wireless device is receiving, has joined, or wants to receive a multicast session, the wireless device evaluates whether the multicast measurement satisfies a specific condition, and if the specific condition is satisfied, the wireless device in the inactive state (e.g., RRC_INACTIVE state) initiates a connection recovery process (e.g., RRC connection recovery process).

[0146] In some implementations, for PDCP measurement, the specific condition may include that the number of lost PDCP SDUs or PDUs within the measurement window is greater than or equal to a threshold. That is, if the number of lost PDCP SDUs or PDUs within the measurement window is greater than or equal to a threshold, it may be determined / evaluated that the specific condition is met. The threshold may be configured by the network. The threshold may be configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

[0147] In some implementations, for PDCP measurement, the specific condition may include that the number of consecutive lost PDCP SDUs or PDUs is greater than or equal to a threshold. That is, if a specific number (e.g., N) of consecutive PDCP SDUs or PDUs are lost, it may be determined / evaluated that the specific condition is met. The specific number (e.g., N) may be configured by the network. The specific number (e.g., N) may be configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

[0148] In some implementations, for RRM measurement, the specific condition may include that the result of the measurement of at least one of the SSB or CSI-RS is lower than a threshold. That is, if the measurement result based on the SSB / CSI-RS becomes lower than the threshold, it can be determined / evaluated that the specific condition is met. The threshold may be configured by the network. The threshold may be configured per multicast session, per multicast session group, or publicly for all multicast sessions provided by the cell.

[0149] In some implementations, information about a specific condition may be obtained. That is, the wireless device may obtain information about a specific condition. For example, the wireless device may receive information about a specific condition from a network.

[0150] In some implementations, the connection recovery process may include sending a connection recovery request message including a new recovery cause to the network. The connection recovery process may include setting a new recovery cause based on the result of the measurement related to the multicast session satisfying a specific condition. For example, if the restoration of the RRC connection is a result of the multicast measurement, the wireless device may set the recovery cause to a new recovery cause (e.g., 'multicast reception') and may send an RRC recovery request message, wherein the recovery cause is set to the new recovery cause.

[0151] In some implementations, the new resumption reason may be notified to the upper layer. For example, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that the resumption reason is 'multicast reception'. In addition, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that the RRC connection needs to be resumed to receive the multicast session in the RRC_CONNECTED state.

[0152] In some implementations, a new access type associated with transitioning from an inactive state to a connected state to receive a multicast session in the connected state may be defined. For example, the new access type may be 'multicast reception'. In addition, the (RRC layer) of the wireless device may inform the NAS layer of the wireless device that the access type is 'multicast reception'.

[0153] In some implementations, the wireless device may communicate with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle.

[0154] Figure 8 The following embodiments of the present disclosure are described: for a UE that is receiving, has joined, or wants to receive a multicast session, if the measurement result of the multicast session meets a specific condition, the UE initiates an RRC connection recovery procedure. However, this is merely exemplary, and the present disclosure may be applied to the following embodiments: for a UE that is receiving, has joined, or wants to receive a multicast session, if the measurement result of the multicast session meets a specific condition, the UE initiates an RRC connection establishment procedure.

[0155] For example, the wireless device may transition from a connected state (e.g., RRC_CONNECTED state) to an idle state (e.g., RRC_IDLE state). The wireless device may receive a multicast session from the network while in the idle state. The wireless device may initiate a connection establishment procedure for transitioning from the idle state (e.g., RRC_IDLE state) to the connected state (e.g., RRC_CONNECTED state) based on the result of the measurement related to the multicast session satisfying a specific condition. That is, if the wireless device is receiving, has joined, or wants to receive a multicast session, the wireless device evaluates whether the multicast measurement satisfies a specific condition, and if the specific condition is satisfied, the wireless device in the idle state (e.g., RRC_IDLE state) initiates a connection establishment procedure (e.g., RRC connection establishment procedure).

[0156] In some implementations, the connection establishment process may include sending a connection establishment request message including a new establishment cause to the network. The connection establishment process may include setting a new establishment cause based on the result of the measurement related to the multicast session satisfying a specific condition. For example, if the establishment of the RRC connection is a result of the multicast measurement, the wireless device may set the establishment cause to a new establishment cause (e.g., 'multicast reception') and may send an RRC establishment request message, wherein the establishment cause is set to the new establishment cause.

[0157] In some implementations, the new establishment cause may be notified to the upper layer. For example, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that the establishment cause is 'multicast reception'. In addition, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that an RRC connection needs to be established to receive the multicast session in the RRC_CONNECTED state.

[0158] In some implementations, a new access type associated with transitioning from an inactive state to a connected state to receive a multicast session in the connected state may be defined. For example, the new access type may be 'multicast reception'. In addition, the (RRC layer) of the wireless device may inform the NAS layer of the wireless device that the access type is 'multicast reception'.

[0159] In addition, the above Figure 8 The method described in the angle of the wireless device can be obtained by Figure 2 The first wireless device 100 and / or Figure 3 The UE 100 shown is used for execution.

[0160] The wireless device includes at least one transceiver, at least one processor, and at least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions, the instructions being executed based on execution by the at least one processor Figure 8 The method described in .

[0161] More specifically, the wireless device transitions from a connected state (eg, RRC_CONNECTED state) to an inactive state (eg, RRC_INACTIVE state).

[0162] The wireless device receives a multicast session from the network while in an inactive state.

[0163] The wireless device performs measurements related to the multicast session. That is, if the wireless device is receiving, has joined, or wants to receive a multicast session, the wireless device may perform multicast measurements.

[0164] In some implementations, the measurement related to the multicast session may be a PDCP measurement, which includes counting the number of lost PDCP SDUs or PDUs of the MRBs associated with the multicast session. That is, for the MRBs associated with the multicast session that the wireless device is receiving, has joined, or wants to receive, the wireless device (the PDCP entity) may detect the number of lost PDCP SDUs or PDUs and count the lost PDCP SDUs or PDUs.

[0165] In some implementations, a measurement window may be configured for PDCP measurement. The number of lost PDCP SDUs or PDUs may be counted within the measurement window. The measurement window may be configured by the network.

[0166] In some implementations, the measurements related to the multicast session may be RRM measurements that include measurements of at least one of an SSB or a CSI-RS associated with a multicast CFR of the receiving multicast session. That is, the wireless device may perform SSB / CSI-RS based measurements based on the SSB / CSI-RS associated with the multicast CFR of the multicast session that the receiving wireless device is receiving, has joined, or wants to receive.

[0167] In some implementations, for RRM measurements, a configuration for at least one of an SSB or CSI-RS associated with a multicast CFR may be provided by the network for an SSB / CSI-RS associated with a multicast CFR and / or a multicast session. For example, the configuration may include an SMTC. An SSB associated with a multicast CFR may be received within or outside the multicast CFR.

[0168] Based on the result of the measurement related to the multicast session satisfying a specific condition, the wireless device initiates a connection recovery process of transitioning from an inactive state (e.g., RRC_INACTIVE state) to a connected state (e.g., RRC_CONNECTED state). That is, if the wireless device is receiving, has joined, or wants to receive a multicast session, the wireless device evaluates whether the multicast measurement satisfies a specific condition, and if the specific condition is satisfied, the wireless device in the inactive state (e.g., RRC_INACTIVE state) initiates a connection recovery process (e.g., RRC connection recovery process).

[0169] In some implementations, for PDCP measurement, the specific condition may include that the number of lost PDCP SDUs or PDUs within the measurement window is greater than or equal to a threshold. That is, if the number of lost PDCP SDUs or PDUs within the measurement window is greater than or equal to a threshold, it may be determined / evaluated that the specific condition is met. The threshold may be configured by the network. The threshold may be configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

[0170] In some implementations, for PDCP measurement, the specific condition may include that the number of consecutive lost PDCP SDUs or PDUs is greater than or equal to a threshold. That is, if a specific number (e.g., N) of consecutive PDCP SDUs or PDUs are lost, it may be determined / evaluated that the specific condition is met. The specific number (e.g., N) may be configured by the network. The specific number (e.g., N) may be configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

[0171] In some implementations, for RRM measurement, the specific condition may include that the result of the measurement of at least one of the SSB or CSI-RS is lower than a threshold. That is, if the measurement result based on the SSB / CSI-RS becomes lower than the threshold, it can be determined / evaluated that the specific condition is met. The threshold may be configured by the network. The threshold may be configured per multicast session, per multicast session group, or publicly for all multicast sessions provided by the cell.

[0172] In some implementations, information about a specific condition may be obtained. That is, the wireless device may obtain information about a specific condition. For example, the wireless device may receive information about a specific condition from a network.

[0173] In some implementations, the connection recovery process may include sending a connection recovery request message including a new recovery cause to the network. The connection recovery process may include setting a new recovery cause based on the result of the measurement related to the multicast session satisfying a specific condition. For example, if the restoration of the RRC connection is a result of the multicast measurement, the wireless device may set the recovery cause to a new recovery cause (e.g., 'multicast reception') and may send an RRC recovery request message, wherein the recovery cause is set to the new recovery cause.

[0174] In some implementations, the new resumption reason may be notified to the upper layer. For example, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that the resumption reason is 'multicast reception'. In addition, the (RRC layer) of the wireless device may notify the NAS layer of the wireless device that the RRC connection needs to be resumed to receive the multicast session in the RRC_CONNECTED state.

[0175] In some implementations, a new access type associated with transitioning from an inactive state to a connected state to receive a multicast session in the connected state may be defined. For example, the new access type may be 'multicast reception'. In addition, the (RRC layer) of the wireless device may inform the NAS layer of the wireless device that the access type is 'multicast reception'.

[0176] In addition, the above Figure 8 The method of describing the angle of the wireless device can be included in Figure 2 The processor 102 in the first wireless device 100 shown controls and / or controls the Figure 3 The processor 102 in the UE 100 shown controls the execution.

[0177] A processing device adapted to control a wireless device includes at least one processor and at least one memory operatively connectable to the at least one processor. The at least one processor is adapted to execute Figure 8 The method described in .

[0178] In addition, the above Figure 8 The method of describing the angle of the wireless device may be stored in a Figure 2 The first wireless device 100 is shown to be executed by software code 105 in the memory 104.

[0179] The technical features of the present disclosure may be implemented directly 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 RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, or any other storage medium.

[0180] Some examples of storage media can be connected to a processor so that the processor can read information from the storage medium. 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.

[0181] The computer-readable medium may include tangible and non-transitory computer-readable storage media.

[0182] For example, non-transitory computer-readable media may include RAM (e.g., synchronous DRAM (SDRAM)), ROM, non-volatile RAM (NVRAM), EEPROM, flash memory, magnetic or optical data storage media, or any other media that can be used to store instructions or data structures. Non-transitory computer-readable media may also include combinations of the above items.

[0183] 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 can be accessed, read, and / or executed by a computer.

[0184] According to some implementations of the present disclosure, a non-transitory computer readable medium (CRM) stores instructions that are executed by at least one processor. Figure 8 The method described in .

[0185] Fig. 9 An example of a method executed by a base station to which an implementation of the present disclosure is applied is shown.

[0186] At step S900 , the method includes sending an RRC release message with a suspension configuration to a wireless device.

[0187] At step S910 , the method includes sending a multicast session to a wireless device while the wireless device is in an inactive state.

[0188] At step S920 , the method includes receiving a connection restoration request message from the wireless device based on a result of the measurement related to the multicast session satisfying a specific condition.

[0189] At step S930 , the method includes sending a multicast session to the wireless device while the wireless device is in a connected state.

[0190] In addition, the above Fig. 9 The method described in the base station angle can be obtained by Figure 2 The second wireless device 200 is shown to perform.

[0191] The base station includes at least one transceiver, at least one processor and at least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions, the instructions being executed based on execution by the at least one processor Fig. 9 The method described in .

[0192] More specifically, the base station sends an RRC release message with a suspension configuration to the wireless device.

[0193] The base station sends the multicast session to the wireless device while the wireless device is in an inactive state.

[0194] Based on the result of the measurement related to the multicast session satisfying a specific condition, the base station receives a connection restoration request message from the wireless device.

[0195] The base station sends the multicast session to the wireless device while the wireless device is in a connected state.

[0196] Fig.10 An example of state transition based on PDCP measurement to which an implementation of the present disclosure is applied is shown.

[0197] At step S1000, the UE receives a PDCP measurement configuration for a multicast session that the UE is currently receiving, has joined, or wants to receive. For example, in the PDCP measurement configuration, it is assumed that the measurement window and the threshold can be set to 500ms and 5, respectively.

[0198] In step S1010 , the UE receives a multicast session via an MRB (eg, MRB# 1 ) in an RRC_IDLE / INACTIVE state.

[0199] At step S1020, the UE counts the number of lost PDCP SDUs / PDUs of an MRB (eg, MRB#1).

[0200] At step S1030, the UE initiates an RRC connection establishment / recovery procedure based on satisfying a trigger condition. For example, the UE may detect more than 5 lost PDCP SDUs / PDUs within a measurement window and may determine / evaluate that the trigger condition is satisfied.

[0201] In step S1040 , the UE receives the multicast session via an MRB (eg, MRB# 1 ) in the RRC_CONNECTED state.

[0202] Fig.11 An example of state transition based on RRC measurement to which an implementation of the present disclosure is applied is shown.

[0203] At step S1100, the UE receives a measurement configuration for a multicast session that the UE is currently receiving, has joined, or wants to receive. For example, the measurement configuration may include an SSB configuration (eg, SMTC) and a threshold.

[0204] At step S1110 , the UE receives a multicast session in a multicast CFR (eg, multicast CFR# 1 ) while being in an RRC_IDLE / INACTIVE state.

[0205] At step S1120 , the UE performs SSB-based measurement using the SSB associated with the multicast CFR (eg, multicast CFR# 1).

[0206] At step S1130, the UE initiates an RRC connection establishment / recovery procedure based on satisfying a trigger condition. For example, a measurement result based on the SSB may become worse than a threshold, and it may be determined / evaluated that the trigger condition is satisfied.

[0207] In step S1140 , the UE receives a multicast session in a multicast CFR (eg, multicast CFR# 1 ) while in the RRC_CONNECTED state.

[0208] The present disclosure may have various beneficial effects.

[0209] For example, when the reception quality of the multicast session in the RRC_IDLE / INACTIVE state is not good enough, the reception quality of the multicast session can be improved by entering the RRC_CONNECTED state.

[0210] The beneficial effects obtained by the specific examples of this specification are not limited to the effects listed above. For example, there may be a variety of technical effects that a person of ordinary skill in the art can understand or derive from this specification. 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.

[0211] The claims in this disclosure can be combined in various ways. For example, the technical features in the method claims of this disclosure can be combined to be implemented or performed in a device, and the technical features in the device claims can be combined to be implemented or performed in a method. In addition, the technical features in the method claims and the device claims can be combined to be implemented or performed in a device. In addition, the technical features in the method claims and the device claims can 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 adapted to operate in a wireless communication system, the method comprising the steps of: Transition from connected state to inactive state; receiving a multicast session from a network while in said inactive state; performing measurements associated with the multicast session; as well as A connection recovery procedure for transitioning from the inactive state to the connected state is initiated based on a result of the measurement related to the multicast session satisfying a specific condition.

2. The method according to claim 1, wherein: The measurement related to the multicast session is a Packet Data Convergence Protocol PDCP measurement, comprising counting a number of lost PDCP Service Data Units SDUs or Protocol Data Units PDUs for a Multicast and Broadcast Service MBS Radio Bearer MRB associated with the multicast session.

3. The method according to claim 2, wherein: The specific condition includes that the number of lost PDCP SDUs or PDCP PDUs within a measurement window is higher than or equal to a threshold.

4. The method according to claim 3, wherein: The measurement window is configured by the network.

5. The method according to claim 2, wherein: The specific condition includes that the number of consecutive lost PDCP SDUs or PDCP PDUs is higher than or equal to a threshold.

6. The method according to any one of claims 3 to 5, wherein: The threshold is configured by the network.

7. The method according to any one of claims 3 to 6, wherein: The threshold is configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

8. The method according to any one of claims 1 to 7, wherein: The measurements related to the multicast session are radio resource management, RRM, measurements including measurements of at least one of a channel state information reference signal, CSI-RS, or a synchronization signal block, SSB, associated with receiving a multicast common frequency resource, CFR, of the multicast session.

9. The method according to claim 8, wherein: Configuration for at least one of the SSB or the CSI-RS associated with the multicast CFR is provided by the network.

10. The method according to claim 8 or 9, wherein: The SSB associated with the multicast CFR is received within the multicast CFR or outside the multicast CFR.

11. The method according to any one of claims 8 to 10, wherein: The specific condition includes that a result of the measurement of at least one of the SSB or the CSI-RS is lower than a threshold.

12. The method according to claim 11, wherein: The threshold is configured by the network.

13. The method according to claim 11 or 12, wherein: The threshold is configured per multicast session, per multicast session group, or commonly for all multicast sessions provided by a cell.

14. The method according to any one of claims 1 to 13, wherein: Information about the specific condition is obtained.

15. The method according to any one of claims 1 to 14, wherein: The connection restoration process includes sending a connection restoration request message including a new restoration reason to the network.

16. The method according to claim 15, wherein: The connection restoration process includes setting the new restoration cause based on the result of the measurement related to the multicast session satisfying the specific condition.

17. The method according to claim 15 or 16, wherein: The new resumption reason is 'multicast reception'.

18. The method according to any one of claims 15 to 17, wherein: The new restoration reason is notified to the upper layer.

19. The method according to any one of claims 1 to 18, wherein: The upper layer is notified of the need to restore the connection to receive the multicast session in the connection state.

20. The method according to any one of claims 1 to 19, wherein: An upper layer is notified of a new access type, the new access type being associated with transitioning from the inactive state to the connected state to receive the multicast session in the connected state.

21. The method according to any one of claims 1 to 20, wherein: The wireless device communicates with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle.

22. A wireless device adapted to operate in a wireless communication system, the wireless device comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory being operatively connectable to the at least one processor and storing instructions, the instructions being executed upon being executed by the at least one processor to perform the method according to any one of claims 1 to 21.

23. A processing device adapted to control a wireless device in a wireless communication system, the processing device comprising: at least one processor; as well as at least one memory operatively connectable to the at least one processor, Wherein, the at least one processor is adapted to perform the method according to any one of claims 1 to 21.

24. A non-transitory computer readable medium (CRM) storing instructions for executing, upon being executed by at least one processor, the method according to any one of claims 1 to 21.

25. A method performed by a base station adapted to operate in a wireless communication system, the method comprising the steps of: sending a radio resource control (RRC) release message with a suspension configuration to the wireless device; sending a multicast session to the wireless device while the wireless device is in an inactive state; receiving a connection restoration request message from the wireless device based on a result of the measurement related to the multicast session satisfying a specific condition; as well as The multicast session is sent to the wireless device while the wireless device is in a connected state.

26. A base station adapted to operate in a wireless communication system, the base station comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory being operatively connectable to the at least one processor and storing instructions, the instructions performing the method according to claim 25 upon being executed by the at least one processor.

Images