State transition based on multicast measurement

Abstract

A method and apparatus for state transition based on multicast measurement are provided. A wireless device receives a multicast session from a network while in an inactive state, and discloses a connection resumption procedure for transitioning to a connected state in the inactive state based on measurement results related to the multicast session satisfying certain conditions.

Description

Technical Field

[0001] The present disclosure relates to state transition based on multicast measurement.

Background Art

[0002] 3GPP (Registered Trademark) (3rd Generation Partnership Project) LTE (Long-Term Evolution) is a technology for enabling high-speed packet communication. Many methods have been proposed for cost reduction for users and operators, improvement of service quality, coverage expansion, and system capacity increase, which are the goals of LTE. 3GPP LTE requires cost reduction per bit, improvement of service usability, flexible use of frequency bands, simple structure, open interface, and appropriate power consumption of terminals as upper-level requirements.

[0003] Work has been started to develop requirements and specifications for the NR (New Radio) system in ITU (International Telecommunication Union) and 3GPP. 3GPP needs to identify and develop the technical components necessary to successfully standardize NR that can timely satisfy all the urgent market requirements and the more long-term requirements presented by the ITU-R (ITU Radio Communication Sector) IMT (International Mobile Telecommunications)-2020 process. Also, NR must be able to utilize any spectrum band up to at least 100 GHz for wireless communication even in the far future.

[0004] NR targets a single technical framework that addresses all deployment scenarios, usage scenarios, and requirements, including eMBB (enhanced Mobile BroadBand), mMTC (massive Machine Type-Communications), URLLC (Ultra-Reliable and Low Latency Communications), etc. NR should be essentially forward compatible.

[0005] 5G Multicast and Broadcast Service (MBS) is an attempt to combine the world of broadcast services with the voice / data world of cellular mobile communications. Since operators want additional revenue sources, they are exploring ways to include broadcast services in their offerings. Consumers are looking for additional ways to continuously connect to the mobile screen in a cost-effective manner, and live TV is an extension of this.

Summary of the Invention

Means for Solving the Problems

[0006] In one form, a method is provided that is executed by a wireless device adapted to operate in a wireless communication system. The method includes receiving a multicast session from a network during an inactive state, and disclosing a connection resume procedure for transitioning to a connected state in the inactive state based on the results of measurements related to the multicast session satisfying certain conditions.

[0007] In other aspects, an apparatus for implementing the method is provided.

Advantages of the Invention

[0008] The present disclosure has various advantages.

[0009] For example, when the reception quality of a multicast session is not good in the RRC_IDLE / INACTIVE state, it is possible to enter the RRC_CONNECTED state to improve the reception quality of the multicast session.

[0010] The effects obtained through specific examples of the present disclosure are not limited to the effects listed above. For example, there are various technical effects that can be understood or induced by a person having ordinary skill in the related art from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to what is explicitly described in the present disclosure, and can include various effects that can be understood or induced from the technical features of the present disclosure.

Brief Description of the Drawings

[0011]

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Best Mode for Carrying Out the Invention

[0012] The following techniques, apparatuses, and systems are applicable to various wireless multiple access systems. Examples of multiple access systems include CDMA (Code Division Multiple Access) systems, FDMA (Frequency Division Multiple Access) systems, TDMA (Time Division Multiple Access) systems, OFDMA (Orthogonal Frequency Division Multiple Access) systems, SC-FDMA (Single Carrier Frequency Division Multiple Access) systems, and MC-FDMA (Multi-Carrier Frequency Division Multiple Access) systems. CDMA is implemented via a wireless technology such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA is implemented via a wireless technology such as GSM (Global System for Mobile communications), GPRS (General Packet Radio Service), or EDGE (Enhanced Data rates for GSM Evolution). OFDMA is implemented via a wireless technology such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802.20, or E-UTRA (Evolved UTRA). UTRA is part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long-Term Evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA. 3GPP LTE uses OFDMA in the downlink (DL; Downlink) and SC-FDMA in the uplink (UL; Uplink).The evolution of 3GPP LTE includes LTE-A (Advanced), LTE-A Pro, and / or 5G NR (New Radio).

[0013] For the sake of convenience in description, the implementations of the present disclosure will mainly be described in relation to 3GPP-based wireless communication systems. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is provided based on a mobile communication system corresponding to a 3GPP-based wireless communication system, aspects of the present disclosure that are not limited to 3GPP-based wireless communication systems are applicable to other mobile communication systems.

[0014] Regarding the terms and techniques used in the present disclosure for which no specific description is given, wireless communication standard documents issued prior to the present disclosure can be referred to.

[0015] In this specification, "A or B" can mean "only A", "only B", or "both A and B". Also, in this specification, "A or B" can be interpreted as "A and / or B". For example, in this specification, "A, B, or C" can mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0016] The slashes ( / ) and commas used in this specification can mean "and / or". For example, "A / B" can mean "A and / or B". Thereby, "A / B" can mean "only A", "only B", or "both A and B". For example, "A, B, C" can mean "A, B, or C".

[0017] In this specification, "at least one of A and B" can mean "only A", "only B", or "both A and B". Also, in this specification, expressions such as "at least one of A or B" and "at least one of A and / or B" can be interpreted in the same way as "at least one of A and B".

[0018] Also, in this specification, "at least one of A, B, and C" can mean "only A", "only B", "only C", or "any combination of A, B, and C". Also, "at least one of A, B, or C" and "at least one of A, B, and / or C" can mean "at least one of A, B, and C".

[0019] Also, the parentheses used in this specification can mean "for example". Specifically, when displayed as "control information (PDCCH)", "PDCCH" is proposed as an example of "control information". Also, the "control information" in this specification is not limited to "PDCCH", but "PDCCH" is proposed as an example of "control information". Also, when displayed as "control information (i.e., PDCCH)", "PDCCH" is proposed as an example of "control information".

[0020] In the present disclosure, the technical features separately described within one drawing may be implemented individually or simultaneously.

[0021] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure are applicable to various fields where wireless communication and / or connection between devices (e.g., 5G) are required.

[0022] Hereinafter, the present disclosure will be described in more detail with reference to the drawings. In the following drawings and / or description, the same reference numerals can refer to the same or corresponding hardware blocks, software blocks, and / or functional blocks unless otherwise indicated.

[0023] FIG. 1 shows an example of a communication system to which the implementation of the present disclosure is applied.

[0024] The 5G usage scenario shown in FIG. 1 is merely an example, and the technical features of the present disclosure are applicable to other 5G usage scenarios not shown in FIG. 1.

[0025] The three main requirement ranges for 5G are (1) the enhanced Mobile Broad Band (eMBB) range, (2) the massive Machine Type Communication (mMTC) range, and (3) the Ultra-Reliable and Low Latency Communications (URLLC) range.

[0026] Referring to FIG. 1, the communication system (1) includes wireless devices 100a to 100f, a base station (BS; 200), and a network 300. Although FIG. 1 describes a 5G network as an example of the network of the communication system (1), the implementation of the present disclosure is not limited to 5G systems and is applicable to future communication systems beyond 5G systems.

[0027] The base station 200 and the network 300 are implemented in the wireless devices, and a specific wireless device can operate as a base station / network node in relation to other wireless devices.

[0028] Wireless devices 100a to 100f represent devices that use radio access technology (RAT) (e.g., 5G NR or LTE) to perform communication and can also be called communication / wireless / 5G devices. Wireless devices 100a to 100f can include, but are not limited to, robot 100a, vehicles 100b-1 and 100b-2, extended reality (XR) device 100c, portable device 100d, home appliance 100e, Internet-of-Things (IoT) device 100f, and artificial intelligence (AI) device / server 400. For example, vehicles can include vehicles with wireless communication functions, autonomous driving vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Vehicles can include unmanned aerial vehicles (UAVs) (e.g., drones). The XR device can include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of a head-mounted device (HMD) or a head-up display (HUD) mounted on vehicles, TVs, smartphones, computers, wearable devices, home appliances, digital signs, vehicles, robots, etc. Portable devices can include smartphones, smart pads, wearable devices (e.g., smartwatches or smart glasses), and computers (e.g., laptops). Home appliances can include TVs, refrigerators, and washing machines. IoT devices can include sensors and smart meters.

[0029] In the present disclosure, the wireless devices 100a to 100f can be referred to as user equipment (UE). The UE can include, for example, a mobile phone, a smartphone, a notebook computer, a digital broadcast terminal, a PDA (Personal Digital Assistant), a PMP (Portable Multimedia Player), a navigation system, a slate PC, a tablet PC, an ultrabook, a vehicle, a vehicle with an autonomous driving function, a connected vehicle, 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 financial device), a security device, a weather / environment device, a 5G service-related device, or a fourth industrial revolution-related device.

[0030] The wireless devices 100a to 100f are connected to the network 300 via the base station 200. AI technology can be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f are connected to the AI server 400 via the network 300. The network 300 is configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a network after 5G. The wireless devices 100a to 100f can communicate with each other via the base station 200 / network 300, but can also communicate directly (e.g., sidelink communication) without going through the base station 200 / network 300. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle-to-Vehicle) / V2X (Vehicle-to-everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0031] Wireless communications / connections 150a, 150b, and 150c are established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and base station 200 and / or between base stations 200. Here, the wireless communications / connections are established via various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, side link communication 150b (or D2D (Device-To-Device) communication), and inter-base station communication 150c (e.g., relay, IAB (Integrated Access and Backhaul)). The wireless devices 100a to 100f and the base station 200 can transmit / receive wireless signals to / from each other via the wireless communications / connections 150a, 150b, and 150c. For example, the wireless communications / connections 150a, 150b, and 150c can transmit / receive signals via various physical channels. Therefore, based on various proposals of the present disclosure, at least a part of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes are executed.

[0032] NR supports a number of numerologies (and / or sub-carrier spacings (SCS)) for supporting various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands; when the SCS is 30 kHz / 60 kHz, it supports dense-urban, lower latency, and a wider carrier bandwidth; when the SCS is 60 kHz or higher, it supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0033] The NR frequency band is defined in two types of frequency ranges (FR1 (Frequency Range 1) and FR2 (Frequency Range 2)). The numerical values of the frequency ranges can be changed. For example, the frequency ranges of the two types (FR1, FR2) are as shown in Table 1 below. For the convenience of explanation, among the frequency ranges used in the NR system, FR1 means "sub 6GHz range" and FR2 means "above 6GHz range", which can be called millimeter wave (mmW).

[0034]

Table 1

[0035] As described above, the numerical values of the frequency ranges of the NR system can be changed. For example, FR1 can include a band from 410 MHz to 7125 MHz together with Table 2 below. For example, FR1 can include a frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 can include an unlicensed band. The unlicensed band can be used for various applications, for example, it can be used for communication for vehicles (e.g., autonomous driving).

[0036]

Table 2

[0037] Here, the wireless communication technology implemented in the wireless device of the present disclosure can include not only LTE, NR, and 6G but also narrowband IoT (NB-IoT, Narrow Band IoT) for low-power communication. For example, NB-IoT technology is an example of LPWAN (Low Power Wide Area Network) technology, and is implemented according to standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-mentioned names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present disclosure can perform communication based on LTE-M technology. For example, LTE-M technology is an example of LPWAN technology and can be called by various names such as eMTC (enhanced MTC). For example, LTE-M technology is implemented in at least one of various standards such as 1) LTE CAT0, 2) LTE CAT M1, 3) LTE CAT M2, 4) LTE non-BL (Non-Bandwidth Limited), 5) LTE-MTC, 6) LTE MTC, and / or 7) LTE M, and is not limited to the above-mentioned names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present disclosure can include at least one of ZigBee (registered trademark), Bluetooth (registered trademark), and / or LPWAN considering low-power communication, and is not limited to the above-mentioned names. For example, ZigBee technology can generate PAN (Personal Area Networks) related to small / low-power digital communication based on various standards such as IEEE802.15.4, and can be called by various names.

[0038] Figure 2 shows an example of a wireless device to which the implementation of the present disclosure is applied.

[0039] In FIG. 2, the first wireless device 100 and / or the second wireless device 200 are implemented in various forms depending on usage examples / services. For example, {the first wireless device 100 and the second wireless device 200} can correspond to at least one of {the wireless devices 100a to 100f and the base station 200} of FIG. 1, {the wireless devices 100a to 100f and the wireless devices 100a to 100f}, and / or {the base station 200 and the base station 200}. The first wireless device 100 and / or the second wireless device 200 are composed of various components, devices / parts, and / or modules.

[0040] The first wireless device 100 can include at least one transceiver such as transceiver 106, at least one processing chip such as processing chip 101, and / or one or more antennas 108.

[0041] The processing chip 101 can include at least one processor such as processor 102 and at least one memory such as memory 104. Further and / or alternatively, the memory 104 can be disposed outside the processing chip 101.

[0042] The processor 102 can control the memory 104 and / or the transceiver 106 and is configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. For example, the processor 102 can process the information in the memory 104 to generate a first information / signal and transmit a wireless signal including the first information / signal via the transceiver 106. The processor 102 can receive a wireless signal including a second information / signal via the transceiver 106 and store the information obtained by processing the second information / signal in the memory 104.

[0043] Memory 104 is connected to processor 102 so as to be operable. Memory 104 can store various types of information and / or instructions. Memory 104 can store firmware and / or software code 105 that implements code, instructions, and / or sets of instructions for executing the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in the present disclosure when executed by processor 102. For example, firmware and / or software code 105 can implement instructions for executing the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in the present disclosure when executed by processor 102. For example, firmware and / or software code 105 can control processor 102 to execute one or more protocols. For example, firmware and / or software code 105 can control processor 102 to execute one or more wireless interface protocol layers.

[0044] Here, processor 102 and memory 104 can be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). Transceiver 106 is connected to processor 102 and can transmit and / or receive wireless signals via one or more antennas 108. Each transceiver 106 can include a transmitter and / or a receiver. Transceiver 106 can be used interchangeably with an RF (Radio Frequency) section. In the present disclosure, the first wireless device 100 can represent a communication modem / circuit / chip.

[0045] The second wireless device 200 can include at least one transceiver such as transceiver 206, at least one processing chip such as processing chip 201, and / or one or more antennas 208.

[0046] Processing chip 201 can include at least one processor such as processor 202 and at least one memory such as memory 204. Additionally and / or alternatively, memory 204 can be disposed outside processing chip 201.

[0047] Processor 202 can control memory 204 and / or transceiver 206 and is configured to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in the present disclosure. For example, processor 202 can process information in memory 204 to generate a third piece of information / signal and transmit a wireless signal including the third piece of information / signal via transceiver 206. Processor 202 can receive a wireless signal including a fourth piece of information / signal via transceiver 206 and store the information obtained by processing the fourth piece of information / signal in memory 204.

[0048] Memory 204 is connected to processor 202 so as to be operable. Memory 204 can store various types of information and / or instructions. Memory 204 can store firmware and / or software code 205 that implements code, instructions, and / or sets of instructions for executing the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in the present disclosure when executed by processor 202. For example, firmware and / or software code 205 can implement instructions for executing the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in the present disclosure when executed by processor 202. For example, firmware and / or software code 205 can control processor 202 to execute one or more protocols. For example, firmware and / or software code 205 can control processor 202 to execute one or more wireless interface protocol layers.

[0049] Here, the processor 202 and the memory 204 can be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 is connected to the processor 202 and can transmit and / or receive wireless signals via one or more antennas 208. Each transceiver 206 can include a transmitter and / or a receiver. The transceiver 206 can be used interchangeably with the RF section. In the present disclosure, the second wireless device 200 can represent a communication modem / circuit / chip.

[0050] Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers are implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 can implement one or more layers (e.g., functional layers such as a PHY (physical) layer, a MAC (Media Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, an RRC (Radio Resource Control) layer, an SDAP (Service Data Adaptation Protocol) layer). One or more processors 102 and 202 can generate one or more PDUs (Protocol Data Units), one or more SDUs (Service Data Units), messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of operations disclosed in this disclosure. One or more processors 102 and 202 can generate a signal (e.g., a baseband signal) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of operations disclosed in this disclosure, and provide it to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive a signal (e.g., a baseband signal) from one or more transceivers 106 and 206, and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of operations disclosed in this disclosure.

[0051] One or more processors 102, 202 can be referred to as a controller, microcontroller, microprocessor, and / or microcomputer. One or more processors 102, 202 are implemented by hardware, firmware, software, and / or combinations thereof. As an example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), and / or one or more FPGAs (Field Programmable Gate Arrays) are included in one or more processors 102, 202. As an example, one or more processors 102, 202 are composed of a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphic processing unit (GPU), and a memory control processor.

[0052] One or more memories 104, 204 are connected to one or more processors 102, 202 and can store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104, 204 are composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read-Only Memory), EPROM (Erasable Programmable ROM), flash memory, volatile memory, non-volatile memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories 104, 204 can be located inside and / or outside the one or more processors 102, 202. Also, the one or more memories 104, 204 are connected to the one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0053] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of the operations disclosed in the present disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of the operations disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 are connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, wireless signals, etc. to one or more other devices. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, wireless signals, etc. from one or more other devices.

[0054] One or more transceivers 106, 206 are connected to one or more antennas 108, 208. Further and / or alternatively, one or more transceivers 106, 206 can include one or more antennas 108, 208. One or more transceivers 106, 206 are configured to transmit and receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or flow diagrams of operations disclosed in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas 108, 208 can be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).

[0055] One or more transceivers 106, 206 can convert received user data, control information, radio signals / channels, etc. into baseband signals in RF band signals in order to process the received user data, control information, radio signals / channels, etc. using one or more processors 102, 202. One or more transceivers 106, 206 can convert user data, control information, radio signals / channels, etc. processed using one or more processors 102, 202 into RF band signals in baseband signals. For that purpose, one or more transceivers 106, 206 can include an (analog) oscillator and / or a filter. For example, one or more transceivers 106, 206 can up-convert an OFDM baseband signal to an OFDM signal via an (analog) oscillator and / or a filter under the control of one or more processors 102, 202 and transmit the up-converted OFDM signal at a carrier frequency. One or more transceivers 106, 206 can receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal via an (analog) oscillator and / or a filter under the control of one or more processors 102, 202.

[0056] Although not shown in FIG. 2, the wireless devices 100 and 200 can further include additional components. The additional component 140 is variously configured depending on the types of the wireless devices 100 and 200. For example, the additional component 140 can include at least one of a power device / 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 component 140 is connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0057] In an implementation of the present disclosure, the UE can operate as a transmitting device in the uplink and as a receiving device in the downlink. In an implementation of the present disclosure, the base station can operate as a receiving device in the UL and as a transmitting device in the DL. Hereinafter, for technical convenience, it is mainly assumed that the first wireless device 100 operates as a UE and the second wireless device 200 operates as a base station. For example, the processor 102 connected to, mounted on, or sold with the first wireless device 100 is configured to execute UE operations according to an implementation of the present disclosure or to control the transceiver 106 to execute UE operations according to an implementation of the present disclosure. The processor 202 connected to, mounted on, or sold with the second wireless device 200 is configured to execute base station operations according to an implementation of the present disclosure or to control the transceiver 206 to execute base station operations according to an implementation of the present disclosure.

[0058] In the present disclosure, the base station can be referred to as a Node B, an eNode B (eNB), or a gNB.

[0059] FIG. 3 shows an example of a UE to which an implementation of the present disclosure is applied.

[0060] Referring to FIG. 3, the UE 100 can correspond to the first wireless device 100 in FIG. 2.

[0061] UE100 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 SIM (Subscriber Identification Module) card 145, a speaker 146, and a microphone 147.

[0062] The processor 102 is configured to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in this disclosure. The processor 102 is configured to control one or more other components of the UE100 to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in this disclosure. Layers of the radio interface protocol are implemented in the processor 102. The processor 102 can include an ASIC, other chip sets, logic circuits, and / or data processing devices. The processor 102 can be an application processor. The processor 102 can include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator). Examples of the processor 102 are Qualcomm's SNAP DRAGON TM series processors, Samsung's EXYNOS TM series processors, Apple's A-series processors, Media Tek's HELIO TM series processors, Intel's ATOM TM series processors or corresponding next-generation processors.

[0063] Memory 104 is combined with the processor 102 to operate and stores various information for operating the processor 102. The memory 104 can include a ROM, a RAM, a flash memory, a memory card, a storage medium, and / or other storage devices. When the implementation is in software, the technologies described herein are implemented using modules (e.g., procedures, functions, etc.) that execute the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this disclosure. The modules are stored in the memory 104 and executed by the processor 102. The memory 104 is implemented within or outside the processor 102 and in this case is communicatively combined with the processor 102 via various methods known in the art.

[0064] The transceiver 106 is combined with the processor 102 to operate and transmits and / or receives wireless signals. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 can include a baseband circuit for processing radio frequency signals. The transceiver 106 controls one or more antennas 108 to transmit and / or receive wireless signals.

[0065] The power management module 141 manages the power supply of the processor 102 and / or the transceiver 106. The battery 142 supplies power to the power management module 141.

[0066] The display 143 outputs the results processed by the processor 102. The keypad 144 receives inputs used in the processor 102. The keypad 144 is displayed on the display 143.

[0067] The SIM card 145 is an integrated circuit for securely storing an IMSI (International Mobile Subscriber Identity) and related keys and is used to identify and authenticate subscribers in mobile phone devices such as mobile phones and computers. Also, contact information can be stored in many SIM cards.

[0068] Speaker 146 outputs the sound-related results processed by processor 102. Microphone 147 receives the sound-related inputs used by processor 102.

[0069] Figures 4 and 5 show examples of protocol stacks in a 3GPP-based wireless communication system to which the implementations of the present disclosure are applied.

[0070] In particular, FIG. 4 shows an example of a user plane protocol stack of a radio interface between a UE and a BS, and FIG. 5 shows an example of a control plane protocol stack of a radio interface between a UE and a BS. The control plane means a path through which control messages used to manage a call between a UE and a network are transmitted. The user plane means a path through which data generated in the application layer, such as voice data or Internet packet data, is transferred. Referring to FIG. 4, the user plane protocol stack can be divided into layer 1 (i.e., the PHY layer) and layer 2. Referring to FIG. 5, the control plane protocol stack can be divided into layer 1 (i.e., the PHY layer), layer 2, layer 3 (e.g., the RRC layer), and the NAS (Non-Access Stratum) layer. Layers 1, 2, and 3 are referred to as the AS (Access Stratum).

[0071] In the 3GPP LTE system, layer 2 is divided into sub-layers of MAC, RLC, and PDCP. In the 3GPP NR system, layer 2 is divided into sub-layers of MAC, RLC, PDCP, and SDAP. The PHY layer provides a transport channel to the MAC sub-layer, the MAC sub-layer provides a logical channel to the RLC sub-layer, the RLC sub-layer provides an RLC channel to the PDCP sub-layer, and the PDCP sub-layer provides a radio bearer to the SDAP sub-layer. The SDAP sub-layer provides a QoS (Quality Of Service) flow to the 5G core network.

[0072] In the 3GPP NR system, the main services and functions of the MAC layer include mapping between logical channels and transport channels, multiplexing / demultiplexing MAC SDUs belonging to one or other logical channels into / from transport blocks (TBs; Transport Blocks) transferred to / from the physical layer on the transport channel, scheduling information reporting, error correction via HARQ (Hybrid Automatic Repeat Request) (one HARQ entity per cell in the case of CA (Carrier Aggregation)), priority handling between UEs by dynamic scheduling, priority handling between logical channels of one UE by logical channel priority assignment, and padding. A single MAC entity can support multiple numerologies, transmission timings, and cells. The mapping restrictions of logical channel priority assignment control the numerologies, cells, and transmission timings available for the logical channels.

[0073] The MAC provides various types of data transmission services. To receive other types of data transmission services, various 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 the type of information to be transmitted. Logical channels are divided into two groups: control channels and traffic channels. Control channels are only used for the transmission of control plane information, and traffic channels are only used for the transmission of user plane information. The BCCH (Broadcast Control Channel) is a downlink logical channel for the broadcast of system control information. The PCCH (Paging Control Channel) is a downlink logical channel that transmits paging information, system information change notifications, and the display of the ongoing Public Warning Service (PWS) broadcast. The CCCH (Common Control Channel) is a logical channel for transmitting control information between the UE and the network and is used for UEs without an RRC connection to the network. The DCCH (Dedicated Control Channel) is a point-to-point bidirectional logical channel for transmitting dedicated control information between the UE and the network and is used by UEs with an RRC connection. The DTCH (Dedicated Traffic Channel) is a point-to-point logical channel dedicated to one UE for the transmission of user information. The DTCH exists in both the uplink and the downlink. The following connections exist between the logical channels and the transport channels in the downlink. The BCCH is mapped to the BCH (Broadcast Channel), the BCCH is mapped to the DL-SCH (Downlink Shared Channel), the PCCH is mapped to the PCH (Paging Channel), the CCCH is mapped to the DL-SCH, the DCCH is mapped to the DL-SCH, and the DTCH is mapped to the DL-SCH. The following connections exist between the logical channels and the transport channels in the uplink.The CCCH is mapped to the UL-SCH (Uplink Shared Channel), the DCCH is mapped to the UL-SCH, and the DTCH is mapped to the UL-SCH.

[0074] The RLC layer supports three transmission modes: TM (Transparent Mode), UM (Unacknowledged Mode), and AM (Acknowledged Mode). RLC configurations can be made for each logical channel independent of numerology and / or transmitters. In the 3GPP NR system, the main services and functions of the RLC layer vary depending on the transmission mode and include the transmission of upper layer PDUs, sequence numbering independent of what is in the PDCP (UM and AM), error correction via ARQ (AM only), segmentation (AM and UM) and reassembly (AM only) of RLC SDUs, reassembly of SDUs (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, protocol error detection (AM only).

[0075] In the 3GPP NR system, the main services and functions of the PDCP layer for the user plane include sequence numbering, header compression and decompression using ROHC (Robust Header Compression), user data transmission, reordering and duplicate detection, in-order delivery, PDCP PPDU routing (in the case of split bearers), retransmission of PDCP PSDUs, encryption, decryption and integrity protection, PDCP PSDU discard, PDCP re-establishment and data recovery for RL CAM, PDCP status reporting for RL CAM, duplication of PDCP PPDUs and indication of duplicate discard to the lower layer. The main services and functions of the PDCP layer for the control plane include sequence numbering, encryption, decryption and integrity protection, control plane data transmission, reordering and duplicate detection, in-order delivery, duplication of PDCP PPDUs and indication of duplicate discard to the lower layer.

[0076] In the 3GPP NR system, the main services and functions of SDAP include the mapping between QoS flows and data radio bearers, and the indication of QoS flow IDs (QFIs; Qos Flow IDs) for all DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

[0077] In the 3GPP NR system, the main services and functions of the RRC layer include the broadcast of system information related to AS and NAS, paging initiated by the 5GC or NG-RAN, the establishment, maintenance, and release of the RRC connection between the UE and the NG-RAN, security functions including key management, the 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 reporting control, detection and recovery of radio link failures, and NAS message transmission in / from / to the UE / NAS.

[0078] FIG. 6 shows the frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied.

[0079] The frame structure shown in FIG. 6 is merely an example, and the number of sub-frames, the number of slots, and / or the number of symbols in a frame can be variously changed. In a 3GPP-based wireless communication system, the OFDM numerology (e.g., SCS (Sub-Carrier Spacing), TTI (Transmission Time Interval) period) can be set differently between a plurality of cells integrated for one UE. For example, when the UE is set to different SCSs for the integrated cells, the (absolute time) duration of a time resource (e.g., sub-frame, slot, or TTI) including the same number of symbols may be different between the integrated cells. Here, the symbol can include an OFDM symbol (or CP-OFDM symbol), an SC-FDMA symbol (or DFT-s-OFDM (Discrete Fourier Transform-Spread-OFDM) symbol).

[0080] Referring to FIG. 6, downlink and uplink transmissions are composed of frames. Each frame has a duration of T f = 10 ms. Each frame is divided into two half-frames, and the duration of each half-frame is 5 ms. Each half-frame is composed of 5 sub-frames, and the duration T sf per sub-frame is 1 ms. Each sub-frame is divided into slots, and the number of slots in a sub-frame depends on the sub-carrier spacing. Each slot includes 14 or 12 OFDM symbols based on the CP (Cyclic Prefix). In the case of normal CP, each slot includes 14 OFDM symbols, and in the case of extended CP, each slot includes 12 OFDM symbols. The numerology is based on the exponentially scalable sub-carrier spacing Δf = 2 u * 15 kHz.

[0081] Table 3 shows the number of OFDM symbols N u per slot for normal CP, the number of slots N slot symb per frame, and the number of slots N frame、uslot and the number of slots per subframe, N subframe、u slot are shown.

[0082] [Table 3]

[0083] Table 4 shows the number of OFDM symbols per slot, N u *15 kHz for the extended CP, the number of slots per frame, N slot symb and the number of slots per subframe, N frame、u slot are shown. subframe、u slot are shown.

[0084] [Table 4]

[0085] A slot contains a plurality of symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N start、u grid starting at N size、u grid、x *N RB sc subcarriers and N subframe、u symb OFDM symbol resource grids are defined. Here, N size、u grid、x is the number of resource blocks (RB) 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 a 3GPP-based wireless communication system, N RB scis generally 12. There is one resource grid for a given antenna port p, subcarrier spacing setting u, and transmission direction (DL or UL). The carrier bandwidth N for subcarrier spacing setting u size、u grid is given by a higher layer parameter (e.g., RRC parameter). Each element of the resource grid for antenna port p and subcarrier spacing setting u is a resource element (RE), and one complex symbol is mapped to each RE. Each RE of the resource grid is uniquely identified by an index k in the frequency domain and an index l representing the symbol position relative to a reference point in the time domain. In a 3GPP-based wireless communication system, an RB is defined for 12 consecutive subcarriers in the frequency domain.

[0086] In a 3GPP NR system, an RB is divided into a CRB and a PRB (Physical Resource Block). The CRB is numbered in the increasing direction in the frequency domain for subcarrier spacing setting u. The center of subcarrier 0 of CRB0 for subcarrier spacing setting u coincides with "Point A" which serves as a common reference point for the resource block grid. In a 3GPP NR system, a PRB is defined within a bandwidth part (BWP; Band Width Part) and is numbered from 0 to N size BWP、i -1. Here, i is the BWP number. The PRBn of BWPi PRB and the CRBn CRB have the following relationship. n PRB = n CRB + N size BWP、i where N size BWP、i is the CRB at which the BWP starts with respect to CRB0. A BWP contains a plurality of consecutive RBs. A carrier can contain a maximum of N (e.g., 5) BWPs. A UE can be set to one or more BWPs on a given serving carrier. Among the BWPs set for the UE, only one BWP is activated at a time. The active BWP defines the operating bandwidth of the UE within the operating bandwidth of the cell.

[0087] In the present disclosure, the term "cell" can mean a geographical area where one or more nodes provide a communication system or can mean radio resources. A "cell" as a geographical area is understood as the coverage in which a node can use a carrier wave to provide services, and a "cell" in terms of radio resources (e.g., time-frequency resources) is related to the bandwidth which is the frequency range set by the carrier wave. A "cell" related to radio resources is defined as a combination of a downlink resource and an uplink resource, for example, a combination of a DLCC (Component Carrier) and a ULCC. A cell may be composed of only downlink resources or may be composed of downlink resources and uplink resources. Since the DL coverage which is the range where a node can transmit an effective signal and the UL coverage which is the range where a node can receive an effective signal from a UE depend on the carrier wave carrying the signal, the coverage of a node may be related to the coverage of a "cell" of the radio resources used by the node. Therefore, the term "cell" is sometimes used to indicate the service coverage of a node, sometimes used to indicate radio resources, or sometimes used to indicate the range where a signal using radio resources can reach an effective strength.

[0088] In CA, two or more CCs are aggregated. The UE can receive or transmit simultaneously in one or various CCs depending on its capabilities. CA is supported for all continuous and discontinuous CCs. Once CA is configured, the UE has only one RRC connection with the network. At RRC connection establishment / re - establishment / handover, one serving cell provides NAS mobility information, and at RRC connection re - establishment / handover, one serving cell provides security input. This cell is called the P Cell (Primary Cell). The P Cell is the cell operating on the primary frequency where the UE executes the initial connection establishment procedure or starts the connection re - establishment procedure. Depending on the UE capabilities, S Cells (Secondary Cells) can be configured to form a set of serving cells together with the P Cell. The S Cell is a cell that provides additional radio resources on the special cell (Sp Cell). Therefore, the set of serving cells configured for the UE always consists of one P Cell and one or more S Cells. In the case of dual - connectivity (DC) operation, the term Sp Cell means the P Cell of the master cell group (MCG; Master Cell Group) or the primary S Cell (PS Cell) of the secondary cell group (SCG; Secondary Cell Group). The Sp Cell supports PUCCH (Physical Uplink Control Channel) transmission and contention - based random access and is always active. The MCG is a group of serving cells related to the master node composed of the Sp Cell (P Cell) and optionally one or more S Cells. The SCG is a group of serving cells related to the secondary node composed of the PS Cell and zero or more S Cells for a UE configured for DC. For a UE in RRC_CONNECTED that is not configured for CA / DC, only one serving cell composed of the P Cell exists. For a UE in RRC_CONNECTED configured for CA / DC, the term "serving cell" is used to indicate the set of cells composed of the Sp Cell(s) and all S Cells.In DC, two MAC entities are configured for the UE. One is for the MCG and the other is for the SCG.

[0089] FIG. 7 shows an example of data flow in a 3GPP NR system to which the implementation of the present disclosure is applied.

[0090] Referring to FIG. 7, "RB" indicates a radio bearer and "H" indicates a header. The radio bearer is divided into two groups: DRB for user plane data and SRB for control plane data. The MAC PDU is transmitted and received with an external device via the PHY layer using radio resources. The MAC PDU arrives at the PHY layer in the form of a transmission block.

[0091] In the PHY layer, the uplink transmission channels UL-SCH and RACH (Random Access Channel) are mapped to the physical channels PUSCH (Physical Uplink Shared Channel) and PRACH (Physical Random Access Channel) respectively, and the downlink transmission channels DL-SCH, BCH, and PCH are mapped to PDSCH (Physical Downlink Shared Channel), PBCH (Physical Broadcast Channel), and PDSCH respectively. In the PHY layer, the uplink control information (UCI; Uplink Control Information) is mapped to the PUCCH (Physical Uplink Control Channel), and the downlink control information (DCI; Downlink Control Information) is mapped to the PDCCH (Physical Downlink Control Channel). The MAC PDU related to the UL-SCH is transmitted by the UE via the PUSCH based on the UL grant, and the MAC PDU related to the DL-SCH is transmitted by the BS via the PDSCH based on the DL allocation.

[0092] The NR system enables efficient transmission of multicast / broadcast services (MBS).

[0093] In the case of a broadcast communication service, the same service and the same specific content data are provided to all UEs simultaneously in a geographical area (i.e., all UEs in the broadcast service area are given the right to receive the data). The broadcast communication service is transferred to the UEs using a broadcast session. UEs can receive the broadcast communication service in the RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states.

[0094] In the case of a multicast communication service, the same service and the same specific content data are provided to a dedicated set of UEs simultaneously (i.e., not all UEs in the multicast service area have the right to receive the data). The multicast communication service is transferred to the UEs using a multicast session. UEs can receive the multicast communication service in the RRC_CONNECTED state via mechanisms such as point-to-point (PTP) and / or point-to-multipoint (PTM) transfer. HARQ feedback / resending is applicable to all PTP and PTM transmissions.

[0095] The multicast service will be described in detail.

[0096] There are two transfer modes:

[0097] - 5GC Shared MBS Traffic Delivery;

[0098] - 5GC Individual MBS Traffic Delivery.

[0099] If the gNB node supports MBS, the network can use 5GC shared MBS traffic delivery, in which case an MBS session resource context for the multicast session is set in the gNB when the first UE joins the multicast session.

[0100] In the case of MBS shared transfer mode, a shared NG-U resource is used to provide MBS user data to the gNB. To allocate a shared NG-U resource for a multicast session, the gNB node discloses a multicast distribution establishment procedure to the 5GC. When multiple MBS session areas are associated with an MBS session for location-dependent MBS services, multiple NG-U shared resources are set for the same multicast session separately for each MBS Area Session ID provided by the gNB.

[0101] The shared NG-U resource applies one of the following transmission options:

[0102] - Unicast transport;

[0103] - Multicast transport.

[0104] In the case of 5GC common MBS traffic transfer, the MBS session resources include one or various individual MBS radio bearers (MRBs). When applied to an MRB given minimized data loss, PDC PSN allocation synchronization is applied via one or a combination of the following methods:

[0105] - Derivation of the PDC PSN using the DL MBS QFI sequence number provided in NG-U;

[0106] - Deployment of shared NG-U termination among gNBs including a common entity for PDC PSN allocation in the shared NG-RAN.

[0107] Synchronization from the perspective of the MBS QoS flow - MRB mapping among gNBs is achieved via network implementation.

[0108] If the PDC PSN is derived from the DL MBS QFI sequence number provided in NG-U and only one QoS flow is mapped to the MRB, the gNB can set the PDC PSN of the PDC PPDU with the value of the DL MBS QFI sequence number provided together with the packet received via NG-U. If the PDC PSN is derived from the DL MBS QFI sequence number provided in NG-U and multiple QoS flows are mapped to the MRB, the gNB can derive the PDC PSN of the PDC PPDU from the sum of the DL MBS QFI sequence numbers of the QoS flows mapped to this MRB.

[0109] The UE can receive data of the MBS multicast session only in the RRC_CONNECTED state. If the UE participating in the multicast session is in the RRC_CONNECTED state and the multicast session is started, the gNB sends an RRC reconfiguration message containing the relevant MBS configuration for the multicast session to the UE, and no separate session activation notification is required for this UE.

[0110] If there is no (temporary) data to be sent to the UE for the multicast session, the gNB can transition the UE to the RRC IDLE / INACTIVE state. When the multicast session is activated by the core network (CN) or there is multicast session data to be transferred by the gNB, the gNB supporting MBS can use the group notification mechanism to notify the UE in the RRC IDLE / INACTIVE state. Upon receiving the group notification, the UE reconnects to the network. The group notification is addressed to the P-RNTI (Paging Radio Network Temporary Identity) on the PDCCH, and the paging channel is monitored by the UE. The paging message for the group notification is utilized to page all the UE in the RRC_IDLE and RRC_INACTIVE states participating in the relevant MBS multicast session, including the MBS session ID. In other words, the UE is not paged individually. If the UE leaves this multicast session, the UE interrupts monitoring for group notifications related to a specific multicast session.

[0111] If a UE in the RRC_IDLE state that has joined an MBS multicast session camps on a gNB that does not support MBS, the UE can receive a notification for multicast session activation or data availability via CN-initiated paging in which the CN pages each UE individually. If a UE in the RRC_INACTIVE state that has joined an MBS multicast session camps on a gNB that does not support MBS, the UE can receive a notification for data availability via RAN-initiated paging.

[0112] The gNB can use the RRC reconfiguration message to configure or reconfigure the multicast MRB (e.g., addition / removal / modification of the RLC entity of the MRB). To minimize data loss due to MRB reconfiguration, the gNB can configure the UE to send PDCP status reports during reconfiguration that causes an MRB type change.

[0113] In the case of a multicast service, the gNB can transfer multicast MBS data packets using the following methods:

[0114] - PTP transmission: The gNB transfers individual copies of the MBS data packets to each UE independently. For example, the gNB schedules a UE-specific PDSCH that is scrambled with the same UE-specific RNTI using a UE-specific PDCCH to which a CRC (Cyclic Redundancy Check) scrambled by a UE-specific RNTI (e.g., C-RNTI (Cell RNTI)) is applied.

[0115] - PTM Transmission: The gNB transfers a single copy of the MBS data packet to a set of UEs. For example, the gNB uses a group common PDCCH scrambled by a group common RNTI and schedules a group common PDSCH scrambled by the same group common RNTI with a CRC applied.

[0116] When the UE has both PTM and PTP transmissions configured, the gNB dynamically determines whether to transfer multicast data to a specific UE over the PTM leg and / or the PTP leg based on information such as MBS session QoS requirements, the number of joined UEs, UE individual feedback on reception quality, and other criteria based on the protocol stack. The same QoS requirements apply regardless of the decision.

[0117] It has been studied that UEs in the RRC_IDLE state and / or the RRC_INACTIVE state can receive a multicast session. UEs in the RRC_IDLE state and / or the RRC_INACTIVE state can receive a multicast session in a BWP-dedicated multicast, that is, in a multicast BWP. The multicast BWP can be called a multicast common frequency resource (CFR).

[0118] The multicast CFR does not overlap with the initial BWP. The initial BWP is used to execute the initial access procedure. The UE can perform cell reselection based on measurements on the initial BWP. That is, the UE can measure the initial BWP of a cell and compare the initial BWP measurement results of each cell. If the initial BWP measurement result of a specific cell meets specific conditions, the UE can reselect the specific cell.

[0119] When the UE performs cell reselection based on measurements for the initial BWP, it is not possible to guarantee the reception quality of the multicast session transmitted in the multicast CFR. When the reception quality of the multicast session in the RRC_INACTIVE state is unsatisfactory (e.g., insufficient), the UE needs to use HARQ retransmission and transition to the RRC_CONNECTED state to receive the multicast session. That is, when the reception quality of the multicast session is not good, the UE needs to transition to the RRC_CONNECTED state to receive the multicast session based on HARQ feedback. Therefore, when the reception quality of the multicast session in the RRC_INACTIVE state is unsatisfactory, it is proposed to specify a solution that enables the UE to resume the RRC connection.

[0120] According to an implementation of the present disclosure, for a UE that is receiving, has joined, or attempts to receive a multicast session, when the measurement result of the multicast session satisfies specific conditions, the UE can disclose the RRC connection setup procedure and / or the RRC connection resume procedure.

[0121] The following drawings are created to illustrate a specific example of the present disclosure. Since the names of the specific devices described in the drawings and the names of the specific signals / messages / fields are presented by way of example, the technical features of the present disclosure are not limited to the specific names used in the following drawings.

[0122] FIG. 8 shows an example of a method executed by a wireless device to which an implementation of the present disclosure is applied.

[0123] In step S800, the method includes a step of transitioning from a connected state (e.g., RRC_CONNECTED state) to an inactive state (e.g., RRC_INACTIVE state).

[0124] In step S810, the method includes a step of receiving a multicast session from the network during the inactive state.

[0125] In step S820, the method includes performing measurements related to the multicast session. That is, when a wireless device is receiving, has joined, or attempts to receive a multicast session, the wireless device can perform multicast measurements.

[0126] In some implementations, the measurements related to the multicast session can be PDCP measurements including counting the number of missing PDC PSDUs or PDUs for the MRB related to the multicast session. That is, for the MBR related to the multicast session that the wireless device is receiving, has joined, or attempts to receive, the wireless device (PDCP entity) can sense and count the missing PDC PSDUs or PDUs.

[0127] In some implementations, a measurement window can be set for PDCP measurements. The number of missing PDC PSDUs or PDUs can be counted within the measurement window. The measurement window can be set by the network.

[0128] In some implementations, the measurements related to the multicast session can be radio resource management (RRM) measurements including measurements for at least one of the multicast CFR and SSB or CSI-RS on which the multicast session is received. That is, the wireless device can perform SSB / CSI-RS based measurements based on the SSB / CSI-RS related to the multicast CFR on which the multicast session that the wireless device is receiving, has joined, or attempts to receive is received.

[0129] In one implementation, for RRM measurement, for the multi-cast CFR and / or the SSB / CSI-RS related to the multi-cast session, at least one of the SSB or the CSI-RS related to the multi-cast CFR is provided by the network with a setting. For example, the setting can include an SSB measurement timing configuration (SMTC). The SSB related to the multi-cast CFR is received inside the multi-cast CFR or outside the multi-cast CFR.

[0130] In step S830, the method includes a step of disclosing a connection resumption procedure for transitioning to the connected state (e.g., RRC_CONNECTED state) in the inactive state (e.g., RRC_INACTIVE state) based on the result of the measurement related to the multi-cast session satisfying a specific condition. That is, when a wireless device is receiving, has joined, or attempts to receive a multi-cast session, the wireless device evaluates whether the multi-cast measurement satisfies a specific condition, and when the specific condition is met, the wireless device in the inactive state (e.g., RRC_INACTIVE state) discloses a connection resumption procedure (e.g., RRC connection resumption procedure).

[0131] In one implementation, for PDCP measurement, the specific condition can include that the number of the missing PDC PSDUs or PDUs within a measurement window is equal to or greater than a threshold. That is, if the number of the missing PDC PSDUs or PDUs within the measurement window is equal to or greater than the threshold, it can be determined / evaluated that the specific condition is satisfied. The threshold can be set by the network. The threshold can be set separately for each multi-cast session, for each multi-cast session group, or commonly for all multi-cast sessions provided in a cell.

[0132] In one implementation, for PDCP measurement, the specific condition may include that the number of consecutive missing PDC PSDUs or PDUs is equal to or greater than a threshold. For example, if a specific number (e.g., N) of consecutive PDC PSDUs or PDUs are missing, it can be determined / evaluated that the trigger condition is met. The specific number (e.g., N) can be set by the network. The specific number (e.g., N) can be set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

[0133] In one implementation, for RRM measurement, the specific condition may include that the measurement result for at least one of the SSB or the CSI-RS is lower than a threshold. That is, when the SSB / CSI-RS based measurement result is lower than the threshold, it can be determined / evaluated that the specific condition is met. The threshold can be set by the network. The threshold can be set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

[0134] In one implementation, information about the specific condition can be obtained. That is, a wireless device can obtain information about the specific condition. For example, the wireless device can receive information about the specific condition from the network.

[0135] In one implementation, the connection resumption procedure may include sending a connection resumption request message including a new resume cause to the network. The connection resumption procedure may include setting the new resume cause based on the result of measurements related to the multicast session satisfying the specific conditions. For example, if the resumption of the RRC connection is the result of multicast measurements, the wireless device may set the resume cause to a new resume cause such as "multicast reception", and may send an RRC resumption request message with the resume cause set to the new resume cause.

[0136] In one implementation, the new resume cause can be notified to the upper layer. For example, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the resume cause is "multicast reception". Also, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the RRC connection needs to be resumed to receive a multicast session in the RRC_CONNECTED state.

[0137] In one implementation, a new access type related to the transition from the inactive state to the connected state to receive the multicast session in the connected state is defined. For example, the new access type can be "multicast reception". Also, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the access type is "multicast reception".

[0138] In one implementation, the wireless device can communicate with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle.

[0139] FIG. 8 illustrates an embodiment of the present disclosure in which a UE discloses an RRC connection resumption procedure when measurement results of a multicast session satisfy specific conditions for a UE that is receiving, has joined, or attempts to receive a multicast session. However, this is merely an example, and the present disclosure is applicable to an embodiment in which a UE discloses an RRC connection establishment procedure when measurement results of a multicast session satisfy specific conditions for a UE that is receiving, has joined, or attempts to receive a multicast session.

[0140] For example, a wireless device can transition from a connected state (e.g., RRC_CONNECTED state) to an idle state (e.g., RRC_IDLE state). The wireless device can receive a multicast session from the network while in the idle state. The wireless device can disclose 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 measurement results related to the multicast session satisfying specific conditions. That is, when the wireless device is receiving, has joined, or attempts to receive a multicast session, the wireless device evaluates whether the multicast measurement satisfies specific conditions, and if the specific conditions are met, the wireless device in the idle state (e.g., RRC_IDLE state) discloses a connection establishment procedure (e.g., an RRC connection establishment procedure).

[0141] In some implementations, the connection establishment procedure can include transmitting a connection establishment request message including a new establishment cause to the network. The connection establishment procedure can include setting a new establishment cause based on measurement results related to the multicast session satisfying specific conditions. For example, if the establishment of an RRC connection is due to the result of this multicast measurement, the wireless device can set the establishment cause to a new establishment cause such as "multicast reception" and transmit an RRC establishment request message with the establishment cause set to the new establishment cause.

[0142] In one implementation, the new establishment cause can be notified to the upper layer. For example, the radio device (RRC layer) can notify the NAS layer of the radio device that the establishment cause is "multicast reception". Also, the radio device (RRC layer) can notify the NAS layer of the radio device that an RRC connection needs to be established to receive a multicast session in the RRC_CONNECTED state.

[0143] In one implementation, a new access type related to transitioning from the inactive state to the connected state to receive a multicast session in the connected state is defined. For example, the new access type can be "multicast reception". Also, the radio device (RRC layer) can notify the NAS layer of the radio device that the access type is "multicast reception".

[0144] Also, the method described from the perspective of the radio device in FIG. 8 is executed by the first radio device 100 shown in FIG. 2 and / or the UE 100 shown in FIG. 3.

[0145] The radio device includes one or more transceivers, one or more processors, and one or more memories storing instructions for executing the method described in FIG. 8 based on being operably connected to the one or more processors and executed by the at least one processor.

[0146] More specifically, the radio device transitions from the connected state (e.g., RRC_CONNECTED state) to the inactive state (e.g., RRC_INACTIVE state).

[0147] The radio device receives a multicast session from the network during the inactive state.

[0148] The wireless device performs measurements related to the multicast session. That is, when the wireless device is receiving, joined to, or attempting to receive a multicast session, the wireless device can perform multicast measurements.

[0149] In some implementations, the measurements related to the multicast session can be PDCP measurements including counting the number of missing PDC PSDUs or PDUs for the MRB related to the multicast session. That is, for the MBR related to the multicast session that the wireless device is receiving, joined to, or attempting to receive, the wireless device (PDCP entity) can sense the missing PDC PSDUs or PDUs and count their number.

[0150] In some implementations, a measurement window can be set for the PDCP measurements. The number of the missing PDC PSDUs or PDUs can be counted within the measurement window. The measurement window can be set by the network.

[0151] In some implementations, the measurements related to the multicast session can be RRM measurements including measurements for at least one of the multicast CFR and SSB or CSI-RS in which the multicast session is received. That is, the wireless device can perform SSB / CSI-RS based measurements based on the SSB / CSI-RS related to the multicast CFR in which the multicast session that the wireless device is receiving, joined to, or attempting to receive is received.

[0152] In one implementation, for RRM measurement, for the multi-cast CFR and / or the SSB / CSI-RS related to the multi-cast session, at least one of the SSB or the CSI-RS related to the multi-cast CFR is provided by the network with respect to the multi-cast CFR. For example, the setting can include SMTC. The SSB related to the multi-cast CFR is received inside the multi-cast CFR or received outside the multi-cast CFR.

[0153] The wireless device discloses a connection resumption procedure for conversion to the connected state (e.g., RRC_CONNECTED state) in the inactive state (e.g., RRC_INACTIVE state) based on the result of measurement related to the multi-cast session satisfying specific conditions. That is, when the wireless device is receiving, joined, or attempting to receive a multi-cast session, the wireless device evaluates whether the multi-cast measurement satisfies specific conditions, and if the specific conditions are met, the wireless device in the inactive state (e.g., RRC_INACTIVE state) discloses a connection resumption procedure (e.g., RRC connection resumption procedure).

[0154] In one implementation, for PDCP measurement, the specific conditions can include that the number of missing PDC PSDUs or PDUs within the measurement window is equal to or greater than a threshold. That is, if the number of missing PDC PSDUs or PDUs within the measurement window is equal to or greater than the threshold, it can be determined / evaluated that the specific conditions are satisfied. The threshold can be set by the network. The threshold can be set separately for each multi-cast session, for each multi-cast session group, or commonly for all multi-cast sessions provided in the cell.

[0155] In one implementation, for PDCP measurement, the specific condition can include that the number of consecutive missing PDC PSDUs or PDUs is equal to or greater than a threshold. For example, if a specific number (e.g., N) of consecutive PDC PSDUs or PDUs are missing, it can be determined / evaluated that the trigger condition is satisfied. The specific number (e.g., N) can be set by the network. The specific number (e.g., N) can be set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

[0156] In one implementation, for RRM measurement, the specific condition can include that the measurement result for at least one of the SSB or the CSI-RS is lower than a threshold. That is, if the SSB / CSI-RS based measurement result is lower than the threshold, it can be determined / evaluated that the specific condition is satisfied. The threshold can be set by the network. The threshold can be set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

[0157] In one implementation, information about the specific condition can be obtained. That is, a wireless device can obtain information about the specific condition. For example, the wireless device can receive information about the specific condition from the network.

[0158] In one implementation, the connection resumption procedure may include sending a connection resumption request message including a new resume cause to the network. The connection resumption procedure may include setting the new resume cause based on the result of measurements related to the multicast session satisfying the specific conditions. For example, if the resumption of the RRC connection is the result of multicast measurements, the wireless device can set the resume cause to a new resume cause such as "multicast reception", and can send an RRC resume request message with the resume cause set to the new resume cause.

[0159] In one implementation, the new resume cause can be notified to the upper layer. For example, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the resume cause is "multicast reception". Also, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the RRC connection needs to be resumed to receive a multicast session in the RRC_CONNECTED state.

[0160] In one implementation, a new access type related to the transition from the inactive state to the connected state for receiving the multicast session in the connected state is defined. For example, the new access type can be "multicast reception". Also, the (RRC layer of the) wireless device can notify the NAS layer of the wireless device that the access type is "multicast reception".

[0161] Also, the method described from the perspective of the wireless device in FIG. 8 is executed under the control of the processor 102 included in the first wireless device 100 shown in FIG. 2 and / or under the control of the processor 102 included in the UE 100 shown in FIG. 3.

[0162] The processing device adapted to control the wireless device includes one or more processors and one or more memories connectable to operate with the one or more processors. The one or more processors are adapted to execute the method described in FIG. 8.

[0163] Also, the method described from the perspective of the wireless device in FIG. 8 is executed by the software code 105 stored in the memory 104 included in the first wireless device 100 shown in FIG. 2.

[0164] The technical features of the present disclosure are implemented directly in hardware, in software executed by a processor, or in a combination of the two. For example, the method executed by the wireless device in wireless communication is implemented in hardware, software, firmware, or a combination thereof. For example, the software can be in RAM, flash memory, ROM, EPROM, EEPROM, registers, a hard disk, a removable disk, a CD-ROM, or other storage media.

[0165] Some examples of the storage medium can be combined with the processor so that the processor can read information in the storage medium. Alternatively, the storage medium is integrated with the processor. The processor and the storage medium can be in an ASIC. In other examples, the processor and the storage medium are present in separate components.

[0166] The computer-readable medium can include a computer-readable storage medium that is of a non-transitory type.

[0167] For example, the non-transitory computer-readable medium can include RAM such as SDRAM (Synchronous Dynamic RAM), ROM, non-volatile NVRAM (Non-Volatile RAM), EEPROM, flash memory, magnetic or optical data storage media, or other media that can be used to store instructions and data structures. The non-transitory computer-readable medium can include combinations thereof.

[0168] Also, the method disclosed herein can be implemented by a computer-readable communication medium that at least partially carries or communicates code in the form of instructions or data structures and can be accessed, read, and / or executed by a computer.

[0169] According to some implementations of the present disclosure, a non-transitory computer-readable medium stores instructions for executing the method described in FIG. 8 based on being executed by at least one processor.

[0170] FIG. 9 shows an example of a method executed by a base station to which an implementation of the present disclosure is applied.

[0171] In step S900, the method includes transmitting a Radio Resource Control (RRC) release message including a suspend configuration to a wireless device.

[0172] In step S910, the method includes transmitting a multicast session to the wireless device while the wireless device is in an inactive state.

[0173] In step S920, the method includes receiving a connection resume request message from the wireless device based on the result of measurements related to the multicast session satisfying certain conditions.

[0174] In step S930, the method includes transmitting the multicast session to the wireless device while the wireless device is in a connected state.

[0175] Also, the method described from the perspective of the base station in FIG. 9 is executed by the second wireless device 200 shown in FIG. 2.

[0176] The base station includes one or more transceivers, one or more processors, and one or more memories that are connected to operate with the one or more processors and store instructions for executing the method described in FIG. 9 based on being executed by the at least one processor.

[0177] More specifically, the base station transmits an RRC release message including a suspend setting to the wireless device.

[0178] The base station transmits a multicast session to the wireless device while the wireless device is in an inactive state.

[0179] The base station receives a connection resume request message from the wireless device based on the result of measurements related to the multicast session satisfying specific conditions.

[0180] The base station transmits the multicast session to the wireless device while the wireless device is in a connected state.

[0181] FIG. 10 shows an example of PDCP measurement-based state transition to which the implementation of the present disclosure is applied.

[0182] In step S1000, the UE receives PDCP measurement settings for a multicast session that the UE is receiving, has joined, or is about to receive. For example, assume that in the PDCP measurement settings, the measurement window and threshold are set to 500 ms and 5 respectively.

[0183] In step S1010, the UE receives a multicast session via an MRB (e.g., MRB#1) in the RRC_IDLE / INACTIVE state.

[0184] In step S1020, the UE counts the number of missing PDC PSDUs / PDUs of the MRB (e.g., MRB#1).

[0185] In step S1030, the UE initiates the RRC connection establishment / resumption procedure based on the satisfaction of the trigger condition. For example, the UE can detect five or more missing PDC PSDUs / PDUs within the measurement window and determine / evaluate that the trigger condition is satisfied.

[0186] In step S1040, the UE receives a multicast session via an MRB (e.g., MRB#1) in the RRC_CONNECTED state.

[0187] Figure 11 shows an example of RRC measurement-based state transition to which the implementation of the present disclosure is applied.

[0188] In step S1100, the UE receives measurement settings for a multicast session that the UE is receiving, has joined, or intends to receive. For example, the measurement settings can include SSB settings (e.g., SMTC) and thresholds.

[0189] In step S1110, the UE receives a multicast session in a multicast CFR (e.g., multicast CFR#1) while in the RRC_IDLE / INACTIVE state.

[0190] In step S1120, the UE performs SSB-based measurements using the SSB associated with the multicast CFR (e.g., multicast CFR#1).

[0191] In step S1130, the UE initiates the RRC connection establishment / resumption procedure based on the satisfaction of the trigger condition. For example, if the SSB-based measurement result is worse than the threshold, it can be determined / evaluated that the trigger condition is satisfied.

[0192] In step S1140, the UE receives a multicast session in a multicast CFR (e.g., multicast CFR#1) while in the RRC_CONNECTED state.

[0193] The present disclosure has various effects.

[0194] For example, when the reception quality of a multicast session is poor in the RRC_IDLE / INACTIVE state, it is possible to enter the RRC_CONNECTED state to improve the reception quality of the multicast session.

[0195] The effects obtained through specific examples of the present disclosure are not limited to the effects listed above. For example, there are various technical effects that can be understood or induced by a person having ordinary skill in the related art from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described in the present disclosure, and can include various effects that can be understood or induced from the technical features of the present disclosure.

[0196] The claims described in the present disclosure can be combined in various ways. For example, the technical features of the method claims of the present disclosure are combined and implemented in a device, and the technical features of the device claims of the present disclosure are combined and implemented as a method. Also, the technical features of the method claims of the present disclosure and the technical features of the device claims of the present disclosure are combined and implemented in a device, and the technical features of the method claims of the present disclosure and the technical features of the device claims of the present disclosure are combined and implemented as a method. Other implementations are within the following claims.

Claims

1. In a method executed by a wireless device adjusted to operate in a wireless communication system, the method comprises: transitioning from a connected state to an inactive state; receiving a multicast session from a network during the inactive state; performing measurements related to the multicast session; and disclosing a connection resume procedure for transitioning from the inactive state to the connected state based on the result of the measurements related to the multicast session satisfying a specific condition.

2. The measurement related to the multicast session is a PDCP measurement including counting the number of missing Packet Data Convergence Protocol (PDCP) service data units (SDUs) or protocol data units (PDUs) for a multicast and broadcast service (MBS) radio bearer (MRB) related to the multicast session, according to the method of Claim 1.

3. The specific condition includes that the number of the missing PDCP SDUs or PDUs is equal to or greater than a threshold within a measurement window, according to the method of Claim 2.

4. The measurement window is set by the network, according to the method of Claim 3.

5. The specific condition includes that the number of consecutive missing PDCP SDUs or PDUs is equal to or greater than a threshold, according to the method of Claim 2.

6. In any one of Claims 3 to 5, the threshold is set by the network.

7. In any one of Claims 3 to 6, the threshold is set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

8. In any one of the first to seventh items, the measurement related to the multicast session is a radio resource management (RRM) measurement including a measurement for at least one of a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS) related to a multicast common frequency resource (CFR) through which the multicast session is received.

9. The method according to claim 8, wherein a setting for at least one of the SSB or the CSI-RS related to the multicast CFR is provided by the network.

10. In item 8 or 9, the SSB related to the multicast CFR is received inside or outside the multicast CFR.

11. In any one of items 8 to 10, the specific condition includes that a measurement result for at least one of the SSB or the CSI-RS is lower than a threshold value.

12. The method according to claim 11, wherein the threshold value is set by the network.

13. In item 11 or 12, the threshold value is set separately for each multicast session, for each multicast session group, or commonly for all multicast sessions provided in a cell.

14. In any one of the first to 13 items, a method for obtaining information about the specific condition.

15. In any one of the first to 14 items, the connection resumption procedure includes transmitting a connection resumption request message including a new resume cause to the network.

16. The method according to claim 15, wherein the connection resumption procedure includes setting the new resume cause based on the result of a measurement related to the multicast session satisfying the specific condition.

17. In item 15 or 16, the new resume cause is "multicast reception".

18. A method for notifying a higher layer of the new resume cause in any one of the first fifth to the first seventh items.

19. A method for notifying a higher layer that it is necessary to resume a connection to receive the multicast session in the connection state in any one of the first item to the first eighth items.

20. A method for notifying a higher layer of a new access type related to the transition to the connected state in the inactive state to receive the multicast session in the connection state in any one of the first item to the first ninth items.

21. A method for the wireless device to communicate with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle in any one of the first item to the twentieth item.

22. In a wireless device adjusted to operate in a wireless communication system, the wireless device includes at least one transceiver, at least one processor, at least one memory connected to be operable by the at least one processor and storing instructions for executing the methods of the first item to the twenty-first item based on being executed by the at least one processor.

23. In a processing apparatus adjusted to control a wireless device in a wireless communication system, the processing apparatus includes at least one processor, at least one memory connectable to be operable by the at least one processor, wherein the at least one processor is adjusted to execute the methods of the first item to the twenty-first item.

24. A non-transitory computer-readable medium (CRM; Computer Readable Medium) storing instructions for executing the methods of the first item to the twenty-first item based on being executed by at least one processor.

25. In a method performed by a base station adjusted to operate in a wireless communication system, the method comprises: transmitting to a wireless device an RRC (Radio Resource Control) release message including a suspend configuration; transmitting to the wireless device a multicast session while the wireless device is in an inactive state; receiving from the wireless device a connection resume request message based on a result of measurements related to the multicast session satisfying certain conditions; A method comprising transmitting the multicast session to the wireless device while the wireless device is in a connected state. **Claim 26** In a base station adjusted to operate in a wireless communication system, the base station comprises: at least one transceiver; at least one processor; at least one memory connected to be operable by the at least one processor and storing instructions for performing the method of claim 25 based on being executed by the at least one processor.

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