MRB retention configuration for MBS on ntn

Abstract

The embodiment of the invention relates to an MRB reservation configuration for an MBS on an NTN. Methods and systems are provided for handling a multicast broadcast service (MBS) radio bearer (MRB) on a non-terrestrial network (NTN). A user equipment (UE) receives an MRB reservation configuration for MBSs from an NTN network node, wherein the UE is configured with one or more MRBs for MBSs of a first service area in which the UE is currently located. In response to leaving the first service area, the UE reserves a configuration of one or more MRBs of the MBS if a determined condition associated with the MRB reservation configuration is satisfied.

Description

Technical Field

[0001] This subject matter generally relates to wireless communication systems, and more particularly to multicast broadcast service providers or enablers thereof. More specifically, this subject matter discloses methods and apparatus for processing radio bearers of multicast broadcast services over non-terrestrial networks. Background Technology

[0002] Wireless telecommunications systems (also known as mobile communication systems) are constantly evolving. When data packets are transmitted from one entity to another (e.g., from one user equipment (UE) to another) over a dedicated channel or resource, this is called one-to-one or unicast communication and forms the basis of most mobile communications today. However, in mobile communications, it is also necessary to transmit data packets simultaneously from one entity to many other entities. This one-to-many communication is called broadcast and multicast communication and can be used, for example, for providing information to the public about disasters or impending dangers, or for critical mission group communications such as emergency services.

[0003] In 3GPP (3rd Generation Partnership Project) mobile communication systems, such as New Radio (NR) / 5G mobile communication systems, Multicast Broadcast Service (MBS) has been defined to provide this one-to-many communication. Communication for MBS is supported by one or more MBS radio bearers (MRBs) configured between network nodes and UEs designed to receive the corresponding MBS information.

[0004] Because MBS is used for specific purposes, it is often limited to or only relevant to certain areas. For example, a specific warning might only apply to a particular geographic area and not to others because it involves government information. Furthermore, there might be specific areas where users should not receive any warnings, such as protected wildlife areas. These areas where MBS should be received are called MBS service areas. When providing MBS to a UE via terrestrial base stations, providing MBS to service areas on demand is not a problem, but this becomes an issue when considering non-terrestrial networks (NTNs).

[0005] The feasibility of using the 5G NR standard to support non-terrestrial networks (NTN) has been studied in 3GPP Releases 15 and 16 of the standardization of mobile / wireless communication systems, and was formally introduced in Release 17. In NTN systems, 5G base stations (gNBs) can be deployed on satellites, and / or satellites can act as relays for terrestrial gNBs, providing communication coverage in extremely wide areas that cellular networks would not otherwise cover. This capability can be used to connect UEs or Internet of Things (IoT) devices globally, and provide personal communication in remote areas and disaster relief scenarios.

[0006] As mentioned earlier, the coverage area (also known as the cell) of such an NTN node or NTN gNB can be very large, for example, up to 3500 km in diameter. Therefore, within the cell of this NTN node, there may be one or more MBS service areas, which are much smaller than the cell and may not be contiguous. Since MBS content typically does not need to be continuously received outside the service area, it is necessary to define how the MRB of this MBS is handled on the NTN. Summary of the Invention

[0007] According to a first aspect of this disclosure, a method performed by a user equipment (UE) for processing multicast broadcast service (MBS) radio bearers (MRBs) over a non-terrestrial network (NTN) is proposed. The method includes: receiving an MRB reservation configuration for an MBS from an NTN network node, wherein the UE is configured with one or more MRBs for an MBS in a first service area where the UE is currently located; and reserving the configuration of one or more MRBs for the MBS in response to leaving the first service area, provided that determined conditions associated with the MRB reservation configuration are met.

[0008] In some embodiments, the method further includes releasing one or more MRBs in response to a determined condition no longer being met. In some other embodiments, the method further includes: suspending MBS reception via one or more MRBs upon leaving a first service area; and resuming MBS reception via one or more MRBs using a reserved configuration of the one or more MRBs of the MBS upon re-entering the first service area or entering a second service area. In yet another embodiment, the MRB reserved configuration is received via a system information block dedicated to transmitting information for the MBS and / or multicast control channels.

[0009] In some embodiments, the MRB retention configuration includes a timer configuration, and the method further includes starting a timer according to the timer configuration in response to leaving the first service area; wherein the determined condition corresponds to determining that the timer is still running.

[0010] In some embodiments, the MRB retains a distance threshold for MBS, and the method further includes detecting the distance to the first service area in response to leaving the first service area; wherein the determined condition corresponds to determining that the distance to the first service area is still less than the distance threshold. In some other embodiments, the distance is related to a hysteresis center distance to the center of the first service area or a hysteresis edge distance to the edge of the first service area.

[0011] In some embodiments, the MRB retention configuration includes a service area release flag associated with a first service area, and the method further includes: releasing one or more MRBs upon leaving the first service area in response to the service area release flag being set; and continuing to retain the configuration of one or more MRBs in response to the service area release flag not being set.

[0012] In some embodiments, the MRB retention configuration includes a service area proximity threshold, and the method further includes: determining a distance between a first service area of ​​the MBS and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; wherein the determined condition corresponds to determining that the distance between the first service area and the second service area is less than the service area proximity threshold.

[0013] In some embodiments, the UE connects to the NTN in accordance with the 3GPP (3rd Generation Partnership Project) 5G technology standard for cellular networks or the 3GPP 6G technology standard for cellular networks.

[0014] According to a second aspect of this disclosure, a UE that processes MRBs on an NTN is proposed, the UE including a memory and a processor configured to receive an MRB reservation configuration of an MBS from an NTN network node, wherein the UE is configured with one or more MRBs for an MBS in a first service area where the UE is currently located; and a configuration to retain one or more MRBs of an MBS in response to leaving the first service area, provided that determined conditions associated with the MRB reservation configuration are met.

[0015] In some embodiments, the processor is also configured to release one or more MRBs in response to a determined condition no longer being met. In some other embodiments, the processor is further configured to suspend MBS reception via one or more MRBs when leaving a first service area; and to resume MBS reception via one or more MRBs using a reserved configuration of the one or more MRBs of the MBS when re-entering the first service area or entering a second service area. In yet another embodiment, the MRB reserved configuration is received via a system information block dedicated to transmitting information for the MBS and / or multicast control channels.

[0016] In some embodiments, the MRB retention configuration includes a timer configuration, and the processor is further configured to start a timer according to the timer configuration in response to leaving the first service area; wherein the determined condition corresponds to determining that the timer is still running.

[0017] In some embodiments, the MRB retains a distance threshold including the MBS, and the processor is further configured to detect the distance to the first service area in response to leaving the first service area; wherein the determined condition corresponds to determining that the distance to the first service area is still less than the distance threshold. In some other embodiments, the distance is related to a hysteresis center distance to the center of the first service area or a hysteresis edge distance to the edge of the first service area.

[0018] In some embodiments, the MRB retention configuration includes a service area release flag associated with a first service area, and the processor is further configured to release one or more MRBs upon leaving the first service area in response to the service area release flag being set; and to continue retaining the configuration of one or more MRBs in response to the service area release flag not being set.

[0019] In some embodiments, the MRB retention configuration includes a service area proximity threshold, and the processor is further configured to determine the distance between a first service area of ​​the MBS and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; wherein the determined condition corresponds to determining that the distance between the first service area and the second service area is less than the service area proximity threshold.

[0020] In some embodiments, the UE connects to the NTN in accordance with the 3GPP (3rd Generation Partnership Project) 5G technology standard for cellular networks or the 3GPP 6G technology standard for cellular networks.

[0021] The above aspects and features can be implemented in systems, apparatuses, methods, articles of art, and non-transitory computer-readable media as required. This subject matter can be implemented and used with a wide variety of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

[0022] This abstract is intended to provide a brief overview of certain aspects and features disclosed under this subject matter. Therefore, it should be understood that the above features are merely illustrative and should not be construed as limiting the scope of the subject matter disclosure in any way. Other features, aspects, and advantages of this subject matter disclosure will become apparent from the following detailed description, drawings, and claims. the term

[0023] To facilitate understanding of the terminology used in this publication, the most relevant abbreviations are provided below: 3GPP Third Generation Partnership Project AMF Access and Mobility Management Functions AS Access Layer CN Core Network eNB LTE base station, E-Utran node B gNB 5G base station, 5G node B GW gateway ID identifier IoT ISL inter-satellite links MBS multicast broadcast service MRB MBS Radio Bearer NG Next Generation NTN non-terrestrial networks PDU (Processing Data Unit) RAN (Radio Access Network) RNTI (Radio Network Temporary Identifier) RRC Radio Resource Control SAT satellite UE User Equipment Attached Figure Description

[0024] The disclosure of this subject matter can be more fully understood when the following detailed description of various embodiments is taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of an example terrestrial wireless communication network is shown;

[0026] Figure 2 A schematic diagram of an example wireless device is shown;

[0027] Figure 3 A schematic diagram of an example network node is shown;

[0028] Figure 4 A schematic diagram of an example non-terrestrial network (NTN) is shown;

[0029] Figures 5A to 5C Examples of scenarios for MRB processing according to this disclosure are provided;

[0030] Figure 6 Example scenarios for inter-satellite handover in NTN fixed Earth cells are provided;

[0031] Figure 7 A flowchart is depicted of a method performed by a user equipment (UE) according to this disclosure;

[0032] Figure 8 Further example improvements to the method according to this disclosure are described;

[0033] Figure 9 A flowchart is depicted showing a method executed by an NTN node according to this disclosure;

[0034] Figure 10 A message signaling diagram of multicast MBS radio bearer processing with a service area proximity threshold is shown according to an embodiment;

[0035] Figure 11 A message signaling diagram of multicast MBS radio bearer processing with a service area release flag according to an embodiment is shown;

[0036] Figure 12 A message signaling diagram of multicast MBS radio bearer processing with timer configuration according to an embodiment is shown;

[0037] Figure 13 A message signaling diagram of multicast MBS radio bearer processing with a distance threshold according to an embodiment is shown;

[0038] Figure 14 A message signaling diagram for multicast MBS radio bearer processing for inter-satellite handover according to an embodiment is shown. Detailed Implementation

[0039] The examples and embodiments described below are intended to provide those skilled in the art with the information needed to implement the content disclosed herein. Those skilled in the art will understand the concepts described and recognize the application of such concepts not specifically mentioned herein after reading the following description and referring to the accompanying drawings. It should be understood that these concepts and their applications fall within the scope of this description.

[0040] Numerous specific details are set forth in the following description. However, it should be understood that various embodiments can be practiced without these specific details. To avoid obscuring the understanding of this description, well-known circuits, structures, and techniques are not shown in detail in the accompanying drawings. Those skilled in the art, possessing knowledge of this description, will be able to implement appropriate functionality without excessive experimentation.

[0041] The use of terms such as "an embodiment," "an embodiment," or "an exemplary embodiment" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment must include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be assumed that those skilled in the art are capable of applying that feature, structure, or characteristic to other embodiments, whether or not it is explicitly described.

[0042] As used herein, “multiple” means two or more. The term “group” as used herein may include one or more such items. Whether in the subject matter disclosure or the claims, the terms “comprising,” “including,” “with,” “having,” “containing,” “involving,” etc., should be understood as open-ended terms, meaning “including but not limited to.” Only the transitional phrases “consisting of…” and “substantially consisting of…” are respectively closed or semi-closed transitional phrases in the claims. The use of ordinal numbers such as “first,” “second,” “third,” etc., to modify an element in the claims or subject matter disclosure does not, in itself, indicate any priority, order, or sequence of that element relative to another element, nor does it indicate the chronological order of method steps; rather, it serves only as a label to distinguish one element with a specific name from another element with the same name (but for use with sequential terms). As used herein, “and / or” and “at least one” mean that the listed items are optional, but optional options also include any combination of the listed items.

[0043] Before elaborating on examples of publicly available information in this topic, let's first combine... Figures 1 to 4 Briefly explain the specific general principles of wireless communication systems to aid in understanding the technology on which the examples are based.

[0044] Figure 1 An example of a terrestrial wireless network 100 that can be used for wireless communication is shown. Note that although this example involves terrestrial wireless communication, many of the principles also apply to non-terrestrial settings. Figure 4 The text provides further explanation.

[0045] Wireless network 100 includes wireless devices (such as UEs 110 (e.g., 110A-110B)) and network nodes (such as radio access nodes 120 (e.g., 120A-120B) (e.g., eNB, gNB, etc.)), which are connected to one or more network nodes 130 via interconnection network 125. Network 100 can be deployed in any suitable scenario. UEs 110 within coverage area 115 can each communicate directly with radio access nodes 120 using either a wireless or air interface. In certain embodiments, UEs 110 can also communicate with each other via D2D communication.

[0046] For example, UE 110A can communicate with radio access node 120A using a wireless or air interface. That is, UE 110A can transmit and / or receive wireless signals from radio access node 120A. The wireless signals may contain voice traffic, data traffic, control signals, and / or any other suitable information. If the UE moves in the area, it can initiate communication (or more generally establish a connection) with radio access node 120B and terminate communication with radio access node 120B (or more generally disconnect). In such cases, radio access node 120A may be referred to as the source base station or the last serving base station, while radio access node 120B may be referred to as the target base station or the new serving base station.

[0047] As used herein, the term "User Equipment" (UE) has its full common meaning and can refer to any type of wireless device that can communicate with network nodes and / or with another UE in a cellular or mobile or wireless communication system. Examples of UEs include target devices, D2D UEs, machine-type UEs or UEs supporting machine-to-machine (M2M) communication, personal digital assistants, tablets, mobile terminals, smartphones, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, ProSe UEs, vehicle-to-vehicle (V2V) UEs, V2X UEs, MTC UEs, eMTC UEs, FeMTC UEs, UE Cat 0, UE CatM1, narrowband Internet of Things (NB-IoT) UEs, UE Cat NB1, etc. Example embodiments of UEs will be described below. Figure 2 To provide a more detailed description.

[0048] In some embodiments, the wireless signal coverage area 115 associated with the radio access node 120 may be referred to as a cell. However, particularly in the context of fifth-generation (5G) / new radio (NR) mobile communication concepts, beamforming can be used for communication within a cell. This principle also applies to NTN, see [link to NTN documentation]. Figure 4 .

[0049] Regarding a beam-based mobile communication system, a radio access node 120 (base station) can transmit beamforming signals to a UE 110 in one or more transmission directions (transmit beam, Tx beam). The UE 110 can receive beamforming signals from the base station 120 in one or more reception directions (receive beam, Rx beam). The UE 110 can also transmit beamforming signals to the base station 120 in one or more directions, and the base station 120 can receive beamforming signals from the UE 110 in one or more directions. The base station 120 and the UE 110 can determine the optimal reception and transmission directions for each base station / UE pair, for example, in the sense of having the highest link quality or otherwise best meeting quality conditions.

[0050] Interconnection network 125 can refer to any interconnected system capable of transmitting audio, video, signals, data, messages, or any combination thereof. Interconnection network 125 may include all or part of the Public Switched Telephone Network (PSTN), public or private data networks, local area networks (LANs), metropolitan area networks (MANs), wide area networks (WANs), local, regional, or global communications or computer networks (such as the Internet), wired or wireless networks, corporate intranets, or any other suitable communication link, including combinations thereof.

[0051] In some embodiments, network node 130 may be a core network node that manages the establishment of communication sessions and various other functions for UE 110. Examples of network node 130 may include a Mobile Switching Center (MSC), MME, Serving Gateway (SGW), Packet Data Network Gateway (PGW), Operation and Maintenance (O&M), Operation Support System (OSS), SON, location node (e.g., Enhanced Serving Mobile Location Center E-SMLC), location server node, MDT node, etc. UE 110 may exchange specific signals with network node 130 using a Non-Access Stratum (NAS) layer. In NAS signaling, signals between UE 110 and network node 130 can transparently traverse the radio access network. In some embodiments, radio access node 120 may interface with one or more network nodes 130 via an inter-node interface.

[0052] As used herein, the term "network node" has its full common meaning and can correspond to any type of radio access node (or radio network node) or any network node that can communicate with a UE and / or with another network node in a cellular or mobile or wireless communication system. Examples of network nodes are NodeB, primary eNB (MeNB), secondary eNB (SeNB), network nodes belonging to MCG or SCG, base stations (BS), multi-standard radio (MSR) radio access nodes (such as MSRBS), eNodeB, network controllers, radio network controllers (RNC), base station controllers (BSC), relays, donor nodes of control relays, base transceiver stations (BTS), access points (AP), transmission points, transmission nodes, RRUs, RRHs, nodes in distributed antenna systems (DAS), core network nodes (such as MSCs, MMEs, etc.), O&M, OSS, self-organizing networks (SON), location nodes (such as E-SMLCs), MDTs, test equipment, etc. Example embodiments of network nodes will be described below. Figure 3 To provide a more detailed description.

[0053] In some embodiments, radio access node 120 may be a distributed radio access node. The components of radio access node 120 and their associated functions may be divided into two main units (or sub-radio network nodes), which may be referred to as a central unit (CU) and a distributed unit (DU). Different distributed radio network node architectures may exist. For example, in some architectures, the DU may be connected to the CU via a dedicated wired or wireless link (such as a fiber optic cable); while in other architectures, the DU may be connected to the CU via a transmission network. Furthermore, how the various functions of radio access node 120 are separated between the CU and the DU may depend on the chosen architecture.

[0054] In some embodiments, radio access nodes 120 can communicate with each other using terrestrial or other connections. In a 5G / NR communication system, communication between radio access nodes 120 can be achieved via an Xn interface, which is used to connect each radio access node 120.

[0055] The example wireless communication system is based on an architecture standardized by the 3rd Generation Partnership Project (3GPP). Developments based on 3GPP are generally referred to as Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) Radio Access Technology (RAT). The various development phases of the 3GPP specification are called Releases. Newer developments of LTE are generally referred to as LTE-Advanced (LTE-A). LTE (LTE-A) employs a radio mobility architecture called Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network called Evolved Packet Core (EPC). Base stations in such systems are called evolved or enhanced Node Bs (eNBs) and provide E-UTRAN functionality to communication devices, including endpoints for user plane packet data aggregation / radio link control / media access control / physical layer protocols (PDCP / RLC / MAC / PHY) and control plane radio resource control (RRC) protocols. Other examples of RATs include those provided by systems based on technologies such as WLAN and / or Global Microwave Access Interoperability (WiMax). Base stations can provide coverage for an entire cell or similar radio service area. The core network elements include the Mobility Management Entity (MME), the Serving Gateway (S-GW), and the Packet Gateway (P-GW).

[0056] Examples of suitable communication systems are the 5G or NR concepts. The network architecture in NR can be similar to that of LTE-A. Base stations in an NR system can be referred to as next-generation node B (gNB). Changes in network architecture may depend on the need to support multiple radio technologies and more granular quality of service (QoS) support, as well as the need for on-demand QoS levels from a user experience (QoE) perspective. Furthermore, network-aware services and applications, and service- and application-aware networks, can also bring about architectural changes. These changes are related to information-centric networks (ICNs) and user-centric content delivery networks (UC-CDNs). NR can employ multiple-input multiple-output (MIMO) antennas, a greater number of base stations or nodes than LTE (the so-called small cell concept), including large sites operating in cooperation with smaller sites, and may employ multiple radio technologies to achieve better coverage and higher data rates. It should be noted that the concepts disclosed in this article are not limited to LTE, and especially not limited to 5G or NR in the context of NTN; they also apply to future networks, such as 6G and beyond, which are being discussed by 3GPP.

[0057] Future networks can leverage Network Functions Virtualization (NFV), a network architecture concept that proposes virtualizing network node functions as "building blocks" or entities that are operatively connected or linked together to provide services. Virtualized network functions (VNFs) can include one or more virtual machines running computer program code using standard or general-purpose type servers instead of custom hardware. Cloud computing or data storage can also be utilized. In radio communications, this could mean that node operations can be performed at least partially in a server, host, or node coupled to a remote radio head. Node operations can also be distributed across multiple servers, nodes, or hosts. It should also be understood that the workforce distribution between core network operations and base station operations may differ from, or even not exist, in LTE.

[0058] An example 5G core network (CN) includes functional entities. The CN connects to the UE via the radio access network (RAN). The User Plane Function (UPF), acting as the PDU Session Anchor (PSA), is responsible for forwarding frames between the data network (DN) and the tunnel established by the 5G network for UEs exchanging services with the DN. The UPF is controlled by the Session Management Function (SMF), which receives policies from the Policy Control Function (PCF). The CN may also include Access and Mobility Functions (AMF).

[0059] In general, all the concepts disclosed herein are applicable to different communication networks, including but not limited to LTE, LTE-A, 5G, 5G-Advanced, 6G, and other future or already implemented networks.

[0060] Figure 2 This is a schematic diagram of an apparatus for a UE. In one embodiment, the apparatus may include a UE; in another embodiment, the apparatus is included within a UE; and in yet another embodiment, the apparatus is a UE. The apparatus may include a wireless device. The apparatus may include at least one processor 220 and at least one memory 230 storing computer program instructions that, when executed by at least one processor 220, cause the apparatus to perform an embodiment of the UE 110 described herein. The UE 110 includes a transceiver 210, a processor 220, a memory 230, and a network interface 240. In some embodiments, the transceiver 210 facilitates the transmission of wireless signals to and from a radio access node 120 (e.g., via a transmitter (Tx), a receiver (Rx), and an antenna). The processor 220 executes instructions to provide some or all of the functions described herein as provided by the UE 110, and the memory 230 stores the instructions executed by the processor 220. In some embodiments, the processor 220 and the memory 230 form a processing circuit system.

[0061] Processor 220 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all of the functions of UE 110 described herein. In some embodiments, processor 220 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or other logic.

[0062] Memory 230 is generally operable to store instructions, such as computer programs, software, applications, including one or more of logic, rules, algorithms, code, tables, etc., and / or other instructions executable by processor 220. Examples of memory 230 include computer memory (e.g., random access memory (RAM) or read-only memory (ROM)), mass storage media (e.g., hard disk), removable storage media (e.g., optical disc (CD) or digital video disc (DVD)), and / or any other volatile or non-volatile, non-transitory computer-readable and / or computer-executable storage device that stores information, data, and / or instructions available for use by processor 220 of UE 110. For example, memory 230 includes computer program code that causes processor 220 to perform the methods described herein.

[0063] Network interface 240 is communicatively coupled to processor 220 and may refer to any suitable device operable to receive input from UE 110, transmit output from UE 110, perform appropriate processing of input or output or both, communicate with other devices or any combination thereof. Network interface 240 may include appropriate hardware (e.g., port, modem, network card, etc.) and software, including protocol conversion and data processing capabilities, for communication over a network.

[0064] Other embodiments of UE 110 may include Figure 2 Additional components, not shown, are responsible for providing specific aspects of the wireless device, including any functions and / or any additional functions described herein (including any functions necessary to support the mechanisms disclosed under this subject matter). For example, UE 110 may include input devices and circuitry, output devices, and one or more synchronization units or circuits, which may be part of processor 220. Input devices include mechanisms for inputting data into UE 110. For example, input devices may include input mechanisms such as a microphone, input element, display, etc. Output devices include mechanisms for outputting data in audio, video, and / or hardcopy formats. For example, output devices may include speakers, displays, etc.

[0065] In some implementations, the wireless device UE 110 may include a series of modules configured to implement the functions of the wireless device described herein. Furthermore, in some embodiments, the UE 110 may also include components for implementing the functions described herein.

[0066] It should be understood that various modules can be implemented through a combination of hardware and software, for example... Figure 2 The processor, memory, and transceiver of the UE 110 shown are illustrated. Some embodiments may also include additional modules to support additional and / or optional functions.

[0067] Figure 3 This is a schematic diagram of an example apparatus for a radio access node 120 (particularly the NTN node described herein) or a network node 130. The apparatus may include at least one processor 320 and at least one memory 330 storing computer program instructions that, when executed by the at least one processor 320, cause the apparatus to perform embodiments of the network node 130 or radio access node 120 described herein. The example radio access node 120 or network node 130 may include one or more of a transceiver 310, a processor 320, a memory 330, and a network interface 340. In some embodiments, the transceiver 310 facilitates the transmission of wireless signals to and from a wireless device (such as UE 110) and the reception of wireless signals from the wireless device (e.g., via a transmitter (Tx), a receiver (Rx), and an antenna). The processor 320 executes instructions to provide some or all of the functions described herein as provided by the radio access node 120 or network node 130, and the memory 330 stores the instructions executed by the processor 320. In some embodiments, the processor 320 and the memory 330 form a processing circuit system. Network interface 340 can transmit signals to backend network components such as gateways, switches, routers, the Internet, the Public Switched Telephone Network (PSTN), core network nodes, or radio network controllers.

[0068] Processor 320 may include any suitable combination of hardware to execute instructions and process data, thereby performing some or all of the functions of the radio access node 120 or network node 130 described herein. In some embodiments, processor 320 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or other logic.

[0069] Memory 330 is generally operable to store instructions, such as computer programs, software, and applications, including one or more of logic, rules, algorithms, code, tables, etc., and / or other instructions executable by processor 320. Examples of memory 330 include computer memory (e.g., random access memory (RAM) or read-only memory (ROM)), mass storage media (e.g., hard disk), removable storage media (e.g., optical disc (CD) or digital video disc (DVD)), and any other volatile or non-volatile, non-transitory computer-readable and / or computer-executable storage device for storing information. For example, memory 330 includes computer program code that causes processor 320 to perform processing according to the methods described herein.

[0070] In some embodiments, network interface 340 is communicatively coupled to processor 320 and may refer to any device suitable for operating to receive input from radio access node 120 or network node 130, transmit output from radio access node 120 or network node 130, perform appropriate processing on the input or output or both, communicate with other devices, or any combination thereof. Network interface 340 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, for communication over a network.

[0071] Other embodiments of radio access node 120 or network node 130 may include Figure 3 Additional components, not shown, are responsible for providing certain functions of the node, including any of the functions described herein and / or any additional functions (including any functions necessary to support the solutions described herein). Different types of radio access nodes or network nodes may include components with the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may partially or completely represent different physical components.

[0072] Regarding Figure 3 The processor, interface, and memory described herein may be included in other nodes (e.g., UE 110, radio access node 120, etc.). Other nodes may selectively include or exclude radio interfaces (e.g., Figure 3 The transceiver).

[0073] In some embodiments, radio access node 120 or network node 130 may include a series of modules configured to implement the functions of radio access node 120 or network node 130 as described herein. Furthermore, in some embodiments, radio access node 120 or network node 130 may also include components for implementing the functions described herein.

[0074] It should be understood that various modules can be implemented through a combination of hardware and software, for example... Figure 3 The radio access node 120 or network node 130 shown includes a processor, memory, and transceiver. Some embodiments may also include additional modules to support additional and / or optional functions.

[0075] Figure 4 Further demonstration Figure 1 The development of terrestrial wireless communication systems is illustrated, namely, Non-Terrestrial Wireless Networks (NTN). NTN refers to a network or network segment that utilizes radio frequency (RF) resources on satellite or UAS platforms. Solutions for supporting NTN in 5G NR have been discussed in 3GPP TR 38.821 and 3GPP TR 38.811 (the full text of which is incorporated herein by reference).

[0076] In practice, NTN refers to the UE 110 or IoT device accessing the radio access node via service link 421 via satellite (also referred to herein as NTN node 401 or NTN gNB 401). NTN node 401 is connected to NTN gateway 402 via feeder link 422, and NTN gateway 402 is connected to core network node 130 to access data network 403. NTN node 401 and NTN gateway 402 can be considered functionally equivalent to... Figure 1 The terrestrial radio access node 120 shown is specifically... Figure 3 The components described herein can also be located in NTN node 401 and / or NTN gateway 402. Furthermore, when NTN node 401 is mentioned below, its functionality may also cover that of NTN gateway 402 if necessary.

[0077] The types of satellites available for deployment vary depending on their orbital altitude. Geostationary orbit (GEO) is at an altitude of approximately 36,000 km. GEO satellites orbit in sync with the Earth's rotation, thus always remaining above the same point on the ground. Currently, hundreds of GEO satellites are in orbit, serving a variety of purposes. Medium Earth orbit (MEO) is at an altitude of approximately 7,000 to 25,000 km. Historically, MEO satellites have been used for geolocation and other navigation applications. Low Earth orbit (LEO) is at an altitude of approximately 300 to 1,500 km. Thousands of satellites are currently in operation in LEO orbit. At least LEO and GEO satellites are currently being considered for 5G NTN.

[0078] Therefore, cell 411 of NTN node 401 can be very large. Cell 411 may consist of one or more beams 412, similar to terrestrial radio configurations. The beam coverage area (i.e., the coverage area of ​​all beams 412 in cell 411) reflects the coverage area of ​​the entire cell, for example: 100 to 1,000 km for LEO satellites, 100 to 1,000 km for MEO satellites, and 200 to 3,500 km for GEO satellites. NTN cells are divided into two categories: Earth Fixed Cells (EFC) and Earth Moving Cells (EMC). EFCs always cover the same area of ​​the Earth's surface, meaning the satellites use steerable beams and switch to other satellites when moving away from the designated area; EMCs move with their satellites. This disclosure primarily considers EFCs, but those skilled in the art will understand that some aspects also apply to EMCs.

[0079] As described above, in the scenario where UE 110 receives MBS via NTN deployment, the concept of an MBS service area is introduced. Information and details about the service area can be propagated to UE 110 through system information blocks (such as SIB20 / SIB21) or through MBS broadcast configurations contained in the multicast control channel (MCCH). MBS service area information can be provided to both the gNB and the UE, as defined in 3GPP TS23.247 (the entire text of which is incorporated herein by reference). Service area information may include geographic area information, such as the area center and coverage diameter, or other otherwise defined areas, and / or municipal address information.

[0080] The service area can be characterized as a specific geographical area within NTN cell 411, or an area that can cover multiple NTN cells 411, within which the UE is allowed or preferentially permitted to receive the configured MBS service content. Therefore, it is a reasonable assumption that multiple MBS service areas can exist within a given NTN cell 411. For example, there may be two towns under a certain NTN cell 411 that both need to receive the same MBS, but the two towns are separated by geographical features (hills, wildlife reserves, rivers, etc.), and MBS content should not be received in this area. Another example is that the coverage area of ​​NTN cell 411 is very large, even spanning two countries separated by international borders, and MBS service is only available in one country, while restricted in the other.

[0081] However, if the service area is a very small area within a given NTN cell 411, and the network restricts UE 110 to receive MBS service only within this restricted service area, then satellite gNB 401 is required to transmit a very narrow and high-gain beam for a given MBS service identified by a specific Temporary Mobile Group Identifier (TMGI) within the geographically restricted service area.

[0082] This will increase the implementation complexity of the NTN gNB 401. Furthermore, even in traditional terrestrial MBS transmission and reception, MBS service reception is transparent to the NTN gNB 401. Therefore, network-based beam-level service area control is not an efficient option. Consequently, the network side (via the NTN gNB 401) should not define any mechanisms using explicit signaling to prevent UE 110 from receiving MBS service content outside the service area or when moving out of the current service area.

[0083] Therefore, when UE 110 enters or leaves the MBS service area, UE 110 can handle the MBS radio bearer (MRB) itself. Before detailing the MRB processing scheme proposed in this disclosure, let's first consider... Figures 5A to 5C and Figure 6 The scenario will be described.

[0084] Figures 5A to 5C Three scenarios are shown, in which cell 411 of NTN gNB 401 contains three MBS serving areas 511, 512, and 513. In all three scenarios, UE 110 is initially located in the first serving area 511 and has been configured with one or more MRBs to receive information for a specific MBS.

[0085] exist Figure 5A In this scenario, the first service area 511 and the second service area 512 are relatively close, and the movement direction 521 of the UE 110 is from the first service area 511 to the second service area 512. If the UE 110 is receiving MBS service identified by a specific TMGI (via the configured MRB) and is configured not to receive this MBS content outside the configured service areas 511, 512, and 513, then the UE 110 will immediately release the MRB when leaving service area 511. Subsequently, once the UE enters another service area 512 or 513 or re-enters service area 511, the UE 110 needs to re-establish the MRB (if the service set is the same, the original MRB may be reused) to continue receiving the MBS content corresponding to the TMGI.

[0086] However, if the distance between service areas 511 and 512 is small, and / or UE 110 has high mobility, releasing the MRB is inefficient because UE 110 is only outside the service area for a very short time. Releasing and re-establishing the MRB in this case would introduce additional and unnecessary processing and complexity. Conversely, if the distance between service areas 511 and 512 is large, and / or UE 110 has low mobility when leaving service area 511 (moving slowly to another service area 512 or 513), then releasing the MRB is meaningful.

[0087] exist Figure 5BIn this scenario, there may be no other service areas 512 or 513 near the current service area 511, but UE 110 is located at the edge of service area 511. Again assuming UE 110 has high (or at least significant) mobility, it may frequently enter and exit service area 511 within a short period along path 522. In this scenario, if UE 110 briefly leaves service area 511 each time and then re-enters it, if UE 110 is configured to release the MRB immediately after leaving a service area, it will result in unnecessary and frequent MRB establishment and release. On the other hand, if UE 110 substantially and permanently (in terms of service) leaves the service area, the MRB should be released to conserve internal resources.

[0088] Figure 5C The scenes basically combine Figure 5A and Figure 5B Two scenarios: Two or more service areas 511, 512, and 513 are adjacent to each other, and UE 110 is located at any edge of the first service area 511. This occurs when UE 110 again has high mobility (but may not be as...). Figure 5A (any different directions in the scene), and UE 110 again has high mobility (but may not have) Figure 5A If the MRB is frequently released and rebuilt, it may move frequently along path 523 from the edge of a service area 511 to another service area 512, 513 or any other direction.

[0089] Figure 6 From another perspective, namely the viewpoint of NTN gNB 401, the handling of MBS and MRB is illustrated. This scenario considers the concept of a fixed tracking area (i.e., EFC 411), whose geographical location on the Earth's surface remains unchanged. EFC 411 again comprises three service areas 511, 512, and 513. UE 110 is located in one of these areas and can therefore be configured with the MRB corresponding to the MBS associated with these service areas 511, 512, and 513.

[0090] In this scenario, an outgoing (previously serving) NTN gNB 401A moves out of the service area for EFC 411, while an incoming (new) NTN gNB 401B takes over EFC 411. Since NTN gNBs 401A and 401B need to switch the corresponding geographical locations of the cells via the inter-satellite link (ISL) 602, the incoming NTN gNB 401B changes its TAC broadcast to reflect the new geographical area covered. Based on this, it can be assumed that the MBS service area will not be affected by the satellite change, therefore no change to the MRB or new configuration is required. Furthermore, updating the service area information again using system information (SIB20 / SIB21 or MCCH) for the new incoming satellite would incur unnecessary overhead and is not the optimal procedure.

[0091] Figures 5A to 5C and Figure 6 The problems encountered in the described scenario can be addressed in this paper and will be discussed in [the following text is missing]. Figures 7 to 14 The solutions described in further detail below address these issues. These solutions can avoid frequent releases and rebuilds of the MRB, as well as the repeated transmission of service area configurations in system information.

[0092] Figure 7 A flowchart of a method performed by a user equipment (UE) according to this disclosure is depicted. This method supports processing Multicast Broadcast Service (MBS) Radio Bearers (MRBs) over a non-terrestrial network (NTN). The method includes receiving an MRB reservation configuration for an MBS from an NTN network node in block 701. The UE 110 is configured with one or more MRBs for the MBS in its current first service area 511. In response to leaving (diamond 702) the first service area 511, the method continues: while a determined condition associated with the MRB reservation configuration (as shown in diamond 703 and indicated by the dashed arrows from block 704 to diamond 703) is met, the configuration of one or more MRBs for that MBS is reserved (block 704).

[0093] In other words, UE 110, located in the first service area 511, receives an RB reservation configuration that indicates to UE 110 under what circumstances / conditions (determined by UE 110 itself) it should retain the MRB currently configured for that MBS (e.g., identified by TMGI) when leaving the first service area 511. These conditions may include those that only apply when leaving the first service area, or those that require continuous monitoring while the UE is outside the first service area 511. For example, the latter type of condition may require UE 110 to continuously monitor its location outside the service area to determine whether its distance from the service area is less than or greater than a certain threshold (as described below). UE 110 may utilize a Global Navigation Satellite System (GNSS) to determine its location, navigation, and / or mobility.

[0094] In some embodiments, MRB reservation configurations may be received via system information blocks (e.g., SIB20, SIB21) and / or multicast control channels (MCCH) dedicated to transmitting MBS information. Some MRB reservation configurations may also be pre-configured or standardized.

[0095] For example, the MRB retention configuration can indicate a service area proximity threshold. UE 110 can, for example, determine before or when leaving the first service area 511 whether other service areas 512, 513 are within the service area proximity threshold, or whether another service area 512 exists within that threshold. If the determination is positive, for example, if another sufficiently close service area exists, or if UE 110 subsequently determines that its mobility to such service areas 512, 513 is sufficiently high, then when UE 110 leaves the first service area 511 along the direction of the second service area 512, and the distance to the second service area 512 is less than the indicated service area proximity threshold (as determined), UE 110 can retain the configuration of one or more MRBs for that MBS. If the determination is negative, for example, if no service area is located within the proximity area specified by the proximity threshold, or if the UE's mobility to the service area is insufficient, then the UE can release the MRB.

[0096] Additionally or alternatively, the MRB retention configuration may indicate a timer configuration. In this example, UE 110 may start a timer according to the timer configuration in response to leaving the first service area 511, and therefore the timer can be observed when UE 110 is outside the first service area 511. In this case, the determined condition may correspond to determining that the timer is still running, and if the timer is still running, UE 110 retains the configuration of one or more MRBs of the MBS when leaving the first service area 511. The MRB can be released when the timer expires.

[0097] Alternatively, the MRB retention configuration may indicate a distance threshold for the MBS configuration. The UE 110 may then monitor (e.g., via continuous GNSS monitoring as described above) its distance from the first service area 511 when leaving the first service area 511. At this point, a determined condition may correspond to determining that its distance from the first service area is (still) less than the distance threshold, and as long as this condition is met, the UE 110 retains the configuration of one or more MRBs for the MBS when leaving the first service area 511. When the distance exceeds the distance threshold, the UE 110 may release the MRB. In these examples, in some embodiments, the distance may refer to a hysteresis center distance to the center of the first service area, or a hysteresis edge distance to the edge of the first service area.

[0098] Additionally, the MRB reservation configuration can indicate a service area release flag associated with the first service area 511. This service area release flag can indicate whether leaving the service area immediately results in MRB release, for example, because a protected area exists around the first service area 511, where MBS reception is not permitted. In response to the service area release flag being set, UE110 can immediately or unconditionally release one or more MRBs (instead of the reservation configuration) upon leaving the first service area. Conversely, if the service area release flag is not set (including cases where the flag does not exist at all), then... Figure 7 As shown in box 704, the configuration of this one or more MRBs is retained.

[0099] Figure 8 Further exemplary improvements to the method according to this disclosure are described. (See also: Regarding...) Figure 7 As explained, the satisfaction of the determined conditions for MRB retention configuration (diamond box 703) can result in the retention of the configuration of one or more MRBs for the MBS when leaving the first service area 511 (box 704). However, if the condition is not satisfied (or is no longer satisfied, especially when it is a condition that needs to be continuously monitored, such as the timer or distance condition described above), the configured MRB can be released, as shown in box 804. This means that UE 110 no longer receives the MBS through the MRB, and—if it re-enters another service area of ​​the same MBS—the MRB configuration needs to be re-established.

[0100] The MRB configuration for retaining MBS can take several forms. In one alternative, the MRB configuration is retained, but UE 110 suspends receiving MBS content when outside any applicable MBS service area (box 805). Therefore, UE 110 can receive but not decode information and ignores MBS content (no information is provided to the user). When UE 110 subsequently re-enters the first service area 511 or the second service area 512 (or the third service area 513), UE 110 can resume receiving MBS content (box 806). In another alternative, MBS content reception continues while the MRB configuration is retained (box 807).

[0101] Figure 9 A flowchart illustrating a method performed by NTN node 401B according to this disclosure is provided. For multicast broadcast services (MBS) in a non-terrestrial network, NTN node 401B performs an inter-satellite handover from outgoing NTN node 401A to its own NTN fixed earth cell (EFC 411) (box 901). Subsequently, NTN node 401B transmits a service area information reuse indication flag for the MBS to UE 110 receiving the MBS in NTN EFC 411 (box 902). This service area information reuse indication flag instructs UE 100 to reuse the MBS service area information configured by outgoing NTN node 401A and continue to use it in incoming NTN node 401B. NTN node 401B can then reuse the service area information received from outgoing NTN node 401A to provide MBS service to UE 110 in EFC 411.

[0102] The service area information reuse indicator flag can be associated with the MBS in some examples, or with a specific service area of ​​the MBS. Therefore, the flag can indicate: reuse all the information provided for the MBS, i.e., the service area information of all service areas 511, 512, and 513; or reuse only specific information, i.e., information specific to a particular service area.

[0103] The service area information reuse indication flag may be transmitted in some embodiments in any of the following ways: in a system information block dedicated to transmitting MBS information (e.g., SIB20, SIB21), in a multicast control channel (MCCH), or in a system information block dedicated to transmitting information required for accessing the corresponding NTN (e.g., SIB19). In some embodiments, NTN node 401B may receive the configured service area information corresponding to the MBS from outgoing NTN node 401A via an inter-satellite link (e.g., ISL 602).

[0104] In other examples, the Serving Area Information Reuse Flag may be transmitted, or only in response to no UE 110 entering the NTN EFC 411 after a confirmed handover; if a new UE 110 has entered the cell, the NTN node 401B will still transmit the complete configuration of the MBS, and all UEs must read the new complete configuration. However, it should be noted that, where applicable, it is more advantageous to always transmit the Serving Area Information Reuse Flag so that UEs with configured MBS MRBs do not need to read the complete configuration in the system information again.

[0105] Figure 10 This diagram illustrates a message signaling diagram of multicast MBS radio bearer processing with a service area proximity threshold according to an embodiment. In this example, UE mobility exists between multiple MBS service areas 511, 512, and 513 within a given NTN cell 411. A given MBS service may be identified by a given TMGI (e.g., TMGI-1) and may be provided in service areas 511 and 512, with the distance between the two areas being less than the service area proximity threshold determined by the network and indicated to UE 110. The UE must not release the MRB associated with that TMGI.

[0106] Core network 130 transmits an NG broadcast establishment request (arrow 1001) to NTN gNB 401. This NG broadcast establishment request may include the MBS identifier (TMI-1), Quality of Service (QoS) information, and service area information for configured service areas, which can be identified by the identifier. In this example, consider a first (current) service area SA1 (e.g., service area 511) and a second service area SA2 (e.g., service area 512).

[0107] NTN gNB 401 then transmits SIB19 (arrow 1002) to NTN UE 110 so that UE 110 can access NTN cell 411. NTN UE 110 reads SIB19 and accesses NTN cell 411 accordingly (box 1003). In addition, NTN UE 110 may then receive SIB20 (and SIB 21, not shown) and MCCH broadcast information (shown by arrow 1004), which contains specific service area information for TMGI-1 and information on the configured service area; furthermore, in this example, NTN UE 110 also receives information on the service area approaching a threshold.

[0108] NTN UE 110 then determines (box 1005) whether the distance between two service areas SA1 and SA2 along the UE's direction of movement is less than a service area proximity threshold. If the distance between the two service areas is less than the service area proximity threshold, UE 110 does not release the MRB (box 1006A). Furthermore (box 1006B), UE 110 may pause the MRB during movement from SA1 to SA2, for example until UE 110 enters SA2 (or re-enters SA1) or pauses for a given duration based on UE 110's movement speed and the distance between the two areas. It should be noted that box 1006B can be combined with... Figures 11 to 13 Any combination of embodiments may be implemented, although these figures are not shown.

[0109] Figure 11 This diagram illustrates a message signaling diagram of multicast MBS radio bearer processing with a service area release flag according to an embodiment. Arrows 1001 and 1002 and box 1003 are shown. Figure 10 The same applies. In this example, the SIB20, SIB21 (although not shown), and / or MCCH broadcast information also include a service area release flag (arrow 1104) for SA1, which is present and set. NTN UE 110 learns that if UE 110 leaves the area where this service area release flag is set, it must immediately release the MRB. Therefore, NTN UE 110 immediately releases the MRB of TMGI-1 when leaving the current service area SA1 (box 1005). It should be noted that the service area release flag is also used in combination with any of the above embodiments, especially with Figure 12 and Figure 13 Examples of the embodiments are used in combination.

[0110] Figure 12 This diagram illustrates a message signaling diagram of multicast MBS radio bearer processing with a timer configuration according to an embodiment. Arrows 1001 and 1002 and box 1003 are shown. Figure 10 The same applies. NTN gNB 401 shares serving area information and timer configuration with UE110 via SIB20 / SIB21 and MCCH (arrow 1204).

[0111] UE 110 detects when it leaves the service area SA1 based on its own location (box 1205). It should be noted that this applies to all embodiments described herein. UE 110 starts a timer for a configured duration (box 1206). If the timer has not expired, UE 110 does not release the MRB (box 1207). If the timer expires, for example, if the UE moves away from the service area SA1 and does not enter another service area of ​​the same MBS, UE 110 will release the MRB (box 1208A). Conversely, if, during the timer's operation, UE 110 re-enters the service area SA1 (or will enter another service area of ​​the same MBS), UE 110 stops the timer (box 1208B) and receives MBS content through the retained MRB.

[0112] Figure 13 This diagram illustrates a message signaling diagram for multicast MBS radio bearer processing with a distance threshold according to an embodiment. Arrows 1001 and 1002 and box 1003 are shown. Figure 10 The same applies. NTN gNB 401 shares service area information and distance thresholds (arrow 1304). This distance threshold can be the hysteresis center distance from the service area center to UE 110, or the hysteresis edge distance from the service area edge to UE 110.

[0113] UE 110 detects when it leaves the service area SA1 (box 1205) based on its own location. Depending on the network configuration, UE 110 takes one of the following actions: if the distance offset between UE 110 and the center of the service area is greater than the hysteresis center distance, it releases the MRB; if the distance offset between UE 110 and the edge of the service area is greater than the hysteresis edge distance, it also releases the MRB. In other words, UE 110 does not release the MRB configuration as long as the hysteresis distance is less than the threshold.

[0114] Figure 14 A message signaling diagram for multicast MBS radio bearer processing for inter-satellite handover according to an embodiment is shown. In this example, NTN UE 110 is in an RRC connection state with the outgoing serving satellite gNB 401A (box 1401). The outgoing serving NTN gNB 401A transmits current service area information to the newly arriving serving NTN gNB 401B via the inter-satellite link (arrow 1402). In some embodiments, the arriving serving NTN gNB 401B may determine that no new UE is camped in NTN cell 411 of the newly arriving serving NTN gNB 401B (box 1403).

[0115] Subsequently, the inbound serving NTN gNB 401B indicates to UE 110 in cell 411 via an explicit indication (i.e., a service area information reuse indication flag) to reuse the service area information previously provided by the outbound serving NTN gNB 401A. This indication is transmitted via either of the following two control signals: SIB20 / MCCH or SIB21 (arrow 1404A) or SIB19 (arrow 1404B). UE 110 then continues to use the MRB configuration of the MBS configured by the outbound serving NTN node 401A and communicates with the new inbound serving NTN node 401B without re-establishing or releasing any MRB.

[0116] The processes described herein can be applied at model or functional levels (identified by identifiers), or across models or functions of a given entity, such as as UE features. It should be understood that the apparatus described herein may include or be coupled to other units or modules, such as radio components or wireless headends for transmission and / or reception. Although the above apparatus is described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0117] Note that although the embodiments have been described with reference to LTE and 5G NR, similar principles can be applied to other networks and communication systems that require forced rapid connection re-establishment. Therefore, although some embodiments have been described above by way of example with reference to specific wireless network architectures, technologies, and standards, these embodiments can be applied to any other suitable form of communication system besides those shown herein.

[0118] It should also be noted that, although exemplary embodiments have been described above, several changes and modifications may be made to the disclosed solutions without departing from the scope of this subject matter disclosure.

[0119] Generally, various exemplary embodiments may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of this disclosure may be implemented in hardware, while others may be implemented in firmware or software executable by a controller, microprocessor, or other computing device, although the subject matter disclosure is not limited thereto. Although aspects of the subject matter disclosure may be represented by block diagrams, flowcharts, or other illustrations, it should be understood that such blocks, apparatuses, systems, techniques, or methods may be implemented in non-limiting examples by hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0120] The exemplary embodiments disclosed in this subject matter may be implemented by computer software executable by a data processor (such as a processor entity) of a mobile device, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products) include software routines, applets, and / or macros, which may be stored in any device-readable data storage medium and contain program instructions for performing specific tasks. A computer program product may include one or more computer-executable components that, when the program runs, are configured to perform the embodiments. The one or more computer-executable components may be at least a piece of software code or a portion thereof.

[0121] Furthermore, it should be noted that any box in the logical flow shown in the diagram may represent a program process, or an interconnecting logic circuit, box, and function, or a combination of a program process and a logic circuit, box, and function. Software may be stored on physical media such as memory chips, memory blocks implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, and CDs. The physical media are non-transient media.

[0122] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include one or more of the following non-limiting examples: general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), FPGAs, gate-level circuits, and processors based on multi-core processor architectures.

[0123] The example embodiments disclosed in this subject can be implemented in various components such as integrated circuit modules. Integrated circuit design is generally a highly automated process. Complex and powerful software tools can be used to transform logic-level designs into semiconductor circuit designs ready for etching and formation on semiconductor substrates.

[0124] Other embodiments disclosed in this subject matter relate to the following examples.

[0125] The first example relates to a method performed by a user equipment (UE) for processing a radio bearer (MRB) of a multicast broadcast service (MBS) on a non-terrestrial network (NTN), comprising: receiving an MRB reservation configuration of the MBS from an NTN network node, wherein the UE is configured with one or more MRBs for the MBS in a first service area where the UE is currently located, wherein the MRB reservation configuration includes a service area proximity threshold; determining a distance between the first service area of ​​the MBS and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; and reserving one or more MRBs of the MBS when leaving the first service area in response to the distance between the first service area and the second service area being less than the service area proximity threshold of the MBS.

[0126] In some embodiments of this first example, the method further includes: releasing one or more MRBs in response to a distance between the first service area and the second service area being greater than a service area proximity threshold of the MBS.

[0127] In some embodiments of this first example, the method further includes: suspending reception of the MBS via one or more MRBs when leaving a first service area; and resuming reception of the MBS via one or more MRBs using a reserved configuration of one or more MRBs of the MBS when entering a second service area.

[0128] In some embodiments of this first example, the MRB reservation configuration is received via a system information block dedicated to transmitting information from the MBS or multicast control channel.

[0129] In some embodiments of this first example, the MRB retention configuration further includes a service area release flag associated with the first service area, and the method further includes releasing one or more MRBs upon leaving the first service area in response to the service area release flag being set; and continuing to determine the distance between the first service area and the second service area in response to the service area release flag not being set.

[0130] In some embodiments of this first example, the UE connects to the NTN according to the 3GPP (3rd Generation Partnership Project) standard for 5G technology for cellular networks or the 3GPP standard for 6G technology for cellular networks.

[0131] In some embodiments of this first example, the first service area and the second service area are located in an NTN fixed cell of an NTN network node.

[0132] In some embodiments of this first example, the MRB retention configuration also includes a timer configuration for the MBS, and the method further includes: starting a timer according to the timer configuration in response to leaving the first service area; stopping the timer in response to entering the second service area or re-entering the first service area while the timer is still running; and releasing one or more MRBs in response to not entering the second service area or re-entering the first service area while the timer is still running.

[0133] The second example relates to a user equipment (UE) that processes multicast broadcast service (MBS) radio bearer (MRB) on a non-terrestrial network (NTN), comprising: a memory; and a processor configured to: receive an MRB reservation configuration for the MBS from an NTN network node, wherein the UE is configured with one or more MRBs for the MBS in a first service area where the UE is currently located, wherein the MRB reservation configuration includes a service area proximity threshold; determine a distance between the first service area and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; and, in response to the distance between the first and second service areas being less than the service area proximity threshold of the MBS, reserve one or more MRBs for the MBS when leaving the first service area.

[0134] In some embodiments of this second example, the processor is also configured to release one or more MRBs in response to the distance between the first service area and the second service area being greater than the service area proximity threshold of the MBS.

[0135] In some embodiments of this second example, the processor is also configured to: suspend reception of the MBS via one or more MRBs when leaving the first service area; and resume reception of the MBS via one or more MRBs using a reserved configuration of one or more MRBs of the MBS when entering the second service area.

[0136] In some embodiments of this second example, the MRB reservation configuration is received via a system information block dedicated to transmitting information from the MBS or multicast control channel.

[0137] In some embodiments of this second example, the MRB retention configuration also includes a service area release flag associated with the first service area, wherein the processor is further configured to: release one or more MRBs upon leaving the first service area in response to the service area release flag being set; and continue to determine the distance between the first service area and the second service area in response to the service area release flag not being set.

[0138] In some embodiments of this second example, the UE connects to the NTN according to the 3GPP (3rd Generation Partnership Project) 5G technology standard for cellular networks or the 3GPP 6G technology standard for cellular networks.

[0139] In some embodiments of this second example, the first service area and the second service area are located in an NTN fixed cell of an NTN network node.

[0140] In some embodiments of this second example, the MRB retention configuration also includes a timer configuration for the MBS, wherein the processor is further configured to: start a timer according to the timer configuration in response to leaving the first service area; stop the timer in response to entering the second service area or re-entering the first service area while the timer is still running; and release one or more MRBs in response to not entering the second service area or re-entering the first service area while the timer is still running.

[0141] The third example relates to a method performed by an inbound non-terrestrial network (NTN) node, comprising: performing an inter-satellite handover of the NTN fixed earth cell (EFC) from the outbound NTN node for a multicast broadcast service (MBS) on the NTN; sending a service area information reuse indication flag of the MBS to a UE served by the MBS in the NTN EFC, wherein the service area information reuse indication flag instructs the UE to reuse the service area information of the MBS configured by the outbound NTN node; and reusing the service area information for providing MBS services to the UE.

[0142] In some embodiments of this third example, the service area information reuse indicator is associated with the MBS or the service area of ​​the MBS.

[0143] In some embodiments of this third example, the service area information reuse indication flag is sent in a system information block dedicated to transmitting MBS information, a multicast control channel, or a system information block dedicated to transmitting information for accessing the corresponding NTN.

[0144] In some embodiments of this third example, the method also includes receiving service area information configured for the MBS from the outgoing NTN node via an inter-satellite link.

[0145] In some embodiments of this third example, the service area information reuse flag is sent in response to determining that no user equipment (UE) enters the NTN EFC after the handover.

[0146] The fourth example relates to an inbound non-terrestrial network (NTN) node, including: a memory; and a processor configured to: perform an inter-satellite handover of the NTN fixed cell EFC from the outbound NTN node for a multicast broadcast service MBS on the NTN; send a service area information reuse indication flag of the MBS to a UE served by the MBS in the NTN EFC, wherein the service area information reuse indication flag instructs the UE to reuse the service area information of the MBS configured by the outbound NTN node; and reuse the service area information for providing MBS services to the UE.

[0147] In some embodiments of this fourth example, the service area information reuse indicator is associated with the MBS or the service area of ​​the MBS.

[0148] In some embodiments of this fourth example, the service area information reuse indication flag is sent in a system information block dedicated to transmitting MBS information, a multicast control channel, or a system information block dedicated to transmitting information for accessing the corresponding NTN.

[0149] In some embodiments of this fourth example, the processor is also configured to:

[0150] Information about the service area configured for MBS is received from the outgoing NTN node via the inter-satellite link.

[0151] In some embodiments of this fourth example, the processor is configured to send a serving area information reuse flag in response to determining that no user equipment (UE) enters the NTN EFC after a handover.

[0152] The fifth example relates to a method performed by a user equipment (UE) supporting multicast broadcast service (MBS), comprising: receiving a service area information reuse indication flag of MBS from an inbound NTN node after an inter-satellite handover of an outbound NTN fixed cell (EFC) from an outbound NTN node; and reusing the service area information of MBS configured by the outbound NTN node.

[0153] In some embodiments of this fifth example, the service area information reuse indicator is associated with the MBS or the service area of ​​the MBS.

[0154] In some embodiments of this fifth example, the service area information reuse indication flag is received in a system information block dedicated to transmitting MBS information, a multicast control channel, or a system information block dedicated to transmitting information for accessing the corresponding NTN.

[0155] The sixth example relates to a user equipment (UE) supporting multicast broadcast service (MBS), including: a memory; and a processor configured to: receive a service area information reuse indication flag of MBS from an inbound NTN node after an inter-satellite handover from an outbound NTN node to a fixed earth cell (EFC) in a non-terrestrial network (NTN); and reuse the service area information of MBS configured by the outbound NTN node.

[0156] In some embodiments of this sixth example, the service area information reuse indicator is associated with the MBS or the service area of ​​the MBS.

[0157] In some embodiments of this sixth example, the service area information reuse indication flag is received in a system information block dedicated to transmitting information for MBS, a multicast control channel, or a system information block dedicated to transmitting information for accessing the corresponding NTN.

[0158] The foregoing description, by way of non-limiting example, has provided a full and complete illustration of exemplary embodiments of the subject matter. However, various modifications and adaptations may be discovered by those skilled in the art when reading the foregoing description in conjunction with the accompanying drawings and claims. Nevertheless, all such modifications, and any similar modifications to the teachings of this disclosure, shall fall within the scope of the subject matter disclosure as defined in the appended claims. In fact, another embodiment exists, which comprises a combination of one or more of the foregoing embodiments with any other embodiments previously discussed.

[0159] The implementation of this disclosure may be described in accordance with the following terms, the features of which may be combined in any reasonable manner.

[0160] Clause 1. A method performed by a user equipment (UE) for processing a radio bearer (MRB) of a multicast broadcast service (MBS) on a non-terrestrial network (NTN), comprising: receiving an MRB reservation configuration of the MBS from an NTN network node, wherein the UE is configured with one or more MRBs of the MBS for a first service area in which the UE is currently located; and reserving a configuration of one or more MRBs of the MBS in response to leaving the first service area, provided that a determined condition associated with the MRB reservation configuration is met.

[0161] Clause 2. The method pursuant to Clause 1 further includes: releasing one or more MRBs in response to the determined condition no longer being met.

[0162] Clause 3. The method pursuant to Clause 1 or 2 further includes: suspending reception of the MBS via one or more MRBs when leaving the first service area; and resuming reception of the MBS via one or more MRBs using a reserved configuration of one or more MRBs of the MBS when re-entering the first service area or entering the second service area.

[0163] Clause 4. The method according to any one of Clauses 1 to 3, wherein the MRB reservation configuration is received via a system information block dedicated to transmitting information of the MBS and / or multicast control channel.

[0164] Clause 5. The method according to any one of Clauses 1 to 4, wherein the MRB retention configuration includes a timer configuration, and the method further includes: in response to leaving the first service area, starting a timer according to the timer configuration; wherein the determined condition corresponds to determining that the timer is still running.

[0165] Clause 6. The method according to any one of Clauses 1 to 5, wherein the MRB retains a distance threshold for the MBS, and the method further includes: in response to leaving the first service area, detecting the distance to the first service area; wherein the determined condition corresponds to determining that the distance to the first service area is still less than the distance threshold.

[0166] Clause 7. The method of Clause 6, wherein the distance relates to the lag center distance to the center of the first service area or the lag edge distance to the edge of the first service area.

[0167] Clause 8. The method according to any one of Clauses 1 to 7, wherein the MRB retention configuration includes a service area release flag associated with the first service area, the method further comprising: releasing one or more MRBs upon leaving the first service area in response to the service area release flag being set; and continuing to retain the configuration of one or more MRBs in response to the service area release flag not being set.

[0168] Clause 9. The method according to any one of Clauses 1 to 8, wherein the MRB reservation configuration includes a service area proximity threshold, and the method further includes: determining a distance between a first service area of ​​the MBS and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; wherein the determined condition corresponds to determining that the distance between the first service area and the second service area is less than the service area proximity threshold.

[0169] Clause 10. The method according to any one of Clauses 1 to 9, wherein the UE connects to the NTN according to the 3GPP (3rd Generation Partnership Project) standard for 5G technology for cellular networks or the 3GPP standard for 6G technology for cellular networks.

[0170] Clause 11. A user equipment (UE) that processes multicast broadcast service MBS radio bearers (MRBs) on a non-terrestrial network (NTN), comprising: a memory; and a processor configured to: receive an MRB reservation configuration for the MBS from an NTN network node, wherein the UE is configured with one or more MRBs for the MBS in a first service area where the UE is currently located; and, in response to leaving the first service area, to reserve one or more MRBs for the MBS if determined conditions associated with the MRB reservation configuration are met.

[0171] Clause 12. The UE pursuant to Clause 11, wherein the processor is further configured to: release one or more MRBs in response to a determined condition no longer being met.

[0172] Clause 13. The UE pursuant to Clause 11 or 12, wherein the processor is further configured to: suspend reception of the MBS via one or more MRBs when leaving the first service area; and resume reception of the MBS via one or more MRBs using a reserved configuration of one or more MRBs of the MBS when re-entering the first service area or entering the second service area.

[0173] Clause 14. A UE pursuant to any of Clauses 11 to 13, wherein the MRB reservation configuration is received via a system information block dedicated to transmitting information of the MBS and / or multicast control channel.

[0174] Clause 15. A UE pursuant to any one of Clauses 11 to 14, wherein the MRB reservation configuration includes a timer configuration, wherein the processor is further configured to: in response to leaving the first service area, start a timer according to the timer configuration; wherein the determined condition corresponds to determining that the timer is still running.

[0175] Clause 16. A UE pursuant to any one of Clauses 11 to 15, wherein the MRB retains a configuration including a distance threshold for the MBS, wherein the processor is further configured to: detect the distance to the first service area in response to leaving the first service area; wherein the determined condition corresponds to determining that the distance to the first service area is still less than the distance threshold.

[0176] Clause 17. The UE pursuant to Clause 16, wherein the distance relates to the hysteresis center distance to the center of the first service area or the hysteresis edge distance to the edge of the first service area.

[0177] Clause 18. A UE pursuant to any one of Clauses 11 to 17, wherein the MRB retention configuration includes a service area release flag associated with a first service area, and the method further includes: releasing one or more MRBs upon leaving the first service area in response to the service area release flag being set; and continuing to retain the configuration of one or more MRBs in response to the service area release flag not being set.

[0178] Clause 19. A UE pursuant to any one of Clauses 11 to 18, wherein the MRB reservation configuration includes a service area proximity threshold, and the method further includes: determining a distance between a first service area of ​​the MBS and a second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; wherein the determined condition corresponds to determining that the distance between the first service area and the second service area is less than the service area proximity threshold.

[0179] Clause 20. A UE pursuant to any one of Clauses 11 to 19, wherein the UE is connected to the NTN in accordance with the 3GPP (3rd Generation Partnership Project) standard for 5G technology for cellular networks or the 3GPP standard for 6G technology for cellular networks.

Claims

1. A communication method executed by a user equipment (UE) for processing a multicast broadcast service (MBS) radio bearer (MRB) on a non-terrestrial network (NTN), comprising: - Receive the MRB reservation configuration from the MBS of the NTN network node, wherein the UE is configured with pins One or more MRBs for the MBS in the first service area where the UE is currently located; as well as - In response to leaving the first service area, the configuration of one or more MRBs of the MBS is retained if the determined conditions associated with the MRB retention configuration are met.

2. The method according to claim 1, further comprising: - In response to the determined condition no longer being met, release the one or more MRBs.

3. The method according to claim 1 or 2, further comprising: - When leaving the first service area, suspend the reception of the MBS through the one or more MRBs; as well as - Upon re-entry into the first service area or into the second service area, the reception of the MBS via the one or more MRBs is restored using the reserved configuration of the MBS.

4. The method according to claim 1 or 2, wherein the MRB reservation configuration is received via a system information block dedicated to transmitting information of the MBS and / or multicast control channel.

5. The method according to claim 1 or 2, wherein the MRB retention configuration includes a timer configuration, and the method further includes: - In response to leaving the first service area, start the timer according to the timer configuration; The determined condition corresponds to determining that the timer is still running.

6. The method of claim 1 or 2, wherein the MRB retention configuration includes a distance threshold for the MBS, and the method further comprises: - In response to leaving the first service area, the distance to the first service area is detected; The determined condition corresponds to determining that the distance to the first service area is still less than the distance threshold.

7. The method of claim 6, wherein the distance relates to a hysteresis center distance to the center of the first service area or a hysteresis edge distance to the edge of the first service area.

8. The method of claim 1 or 2, wherein the MRB retention configuration includes a service area release flag associated with the first service area, and the method further comprises: - In response to the service area release flag being set, release the one or more MRBs when leaving the first service area; as well as - In response to the service area release flag not being set, the configuration of the one or more MRBs continues to be maintained.

9. The method of claim 1 or 2, wherein the MRB retention configuration includes a service area proximity threshold, and the method further comprises: - Determine the distance between the first service area of ​​the MBS and the second service area of ​​the MBS, wherein the second service area is located in the direction of movement of the UE; The determined condition corresponds to determining that the distance between the first service area and the second service area is less than the service area proximity threshold.

10. The method according to claim 1 or 2, wherein the UE is connected to the NTN according to the 3GPP (3rd Generation Partnership Project) 5G standard for cellular networks or the 3GPP 6G standard for cellular networks.

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