System and method for managing multimedia broadcast multicast service (MBMS) continuity

Abstract

A system and method for managing multimedia broadcast multicast service (MBMS) continuity. The system and method include transmitting a first message to a central unit (CU) of a wireless communication node by a wireless communication device through a first distributed unit (DU) of the wireless communication node. The first DU corresponds to a first subset of multiple MBMS services of the CU. The first message indicates a second subset of multiple MBMS services corresponding to a second DU of the wireless communication node. The system and method include receiving, by the wireless communication device, a second message including MBMS scheduling information from the CU in response to transmitting the first message. The system and method include performing, by the wireless communication device, a switching process from the first DU to the second DU.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications and, more particularly, to systems and methods for managing Multimedia Broadcast Multicast Service (MBMS) continuity. Background Art

[0002] MBMS (Multimedia Broadcast Multicast Service) is a point-to-multipoint interface specification for 3GPP cellular networks. Providing efficient broadcast and multicast services in cellular and core networks is the cornerstone of mobile TV services. For broadcast transmission across cellular lines, MBMS defines the transmission mode using a single frequency network configuration. As mobile communications enter the LTE stage, MBMS technology has evolved into eMBMS (enhanced Multimedia Broadcast Multicast Service) in 4G communications to meet the growing business needs. Summary of the invention

[0003] The exemplary embodiments disclosed herein are intended to solve problems associated with one or more problems presented in the prior art, as well as to provide additional features that will become apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of example and are not restrictive, and it will be apparent to a person of ordinary skill in the art who reads this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0004] The present disclosure relates to systems and methods for managing Multimedia Broadcast Multicast Service (MBMS) continuity.

[0005] In general, as discussed in more detail below, the MBMSInterestIndication message reported by the UE may include a list of services (ServicesListMBMS) of interest to the UE and be prioritized. The CU may add a process for transmitting MBMS scheduling information to the UE before the UE is handed over to the target cell, i.e., before receiving the UE context setup response from the target DU. Alternatively, the CU may add a process for transmitting MBMS scheduling information to the UE after the UE is handed over to the target cell, i.e., after receiving the UL RRC message transmission message from the target DU.

[0006] MBMS scheduling information may be carried in a new (e.g., novel, updated, different, etc.) SIB message. MBMS scheduling information may be carried by a dedicated RRC message and forwarded to the UE over the F1 interface and / or the air interface. MBMS scheduling information may be transmitted to the source DU by a new F1 interface message.

[0007] One aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes transmitting a first message to a central unit (CU) of a wireless communication node by a wireless communication device through a first distributed unit (DU) of the wireless communication node. In some embodiments, the first DU corresponds to a first subset of multiple multimedia broadcast multicast service (MBMS) services of the CU. The first message indicates a second subset of multiple MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method also includes receiving, by the wireless communication device, a second message including MBMS scheduling information from the CU in response to transmitting the first message. In some embodiments, the method also includes performing a switching process from the first DU to the second DU by the wireless communication device.

[0008] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective service identifier.

[0009] In some embodiments, receiving the second message further comprises receiving MBMS scheduling information from the first DU via a dedicated RRC message.In some embodiments, the MBMS scheduling information is transmitted from the CU to the first DU via a newly defined F1 interface message.

[0010] In some embodiments, receiving the second message further comprises receiving MBMS scheduling information from the first DU via a newly defined system information block (SIB) in response to the first DU receiving a system information delivery command from the CU.

[0011] Another aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes receiving a first message from a wireless communication device by a central unit (CU) of a wireless communication node through a first distributed unit (DU) of the wireless communication node. In some embodiments, the first DU corresponds to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU. In some embodiments, the first message indicates a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method includes transmitting a second message including MBMS scheduling information to the wireless communication device by the CU in response to receiving the first message. In some embodiments, the method includes causing the wireless communication device to perform a switching process from the first DU to the second DU.

[0012] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective service identifier.

[0013] In some embodiments, transmitting the second message further comprises transmitting a newly defined F1 interface message including the MBMS scheduling information to the first DU through the CU, so that the first DU transmits the MBMS scheduling information to the wireless communication device through a dedicated RRC message.

[0014] In some embodiments, transmitting the second message further includes transmitting, by the CU, a system information delivery command to the first DU, so that the first DU transmits the MBMS scheduling information via a newly defined system information block (SIB).

[0015] Another aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes receiving a first message from a wireless communication device by a first distributed unit (DU) of a wireless communication node. In some embodiments, the first DU corresponds to a first subset of multiple multimedia broadcast multicast service (MBMS) services of the CU. In some embodiments, the first message indicates a second subset of multiple MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method includes transmitting a first message to a central unit (CU) of the wireless communication node by the first DU. In some embodiments, the method includes receiving a second message from the DU by the first DU. In some embodiments, the method includes transmitting a third message including MBMS scheduling information to the wireless communication device by the first DU in response to receiving the second message, so that the wireless communication device performs a switching process from the first DU to the second DU.

[0016] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective service identifier.

[0017] In some embodiments, receiving the second message further comprises receiving a newly defined F1 interface message from the CU via the first DU, which comprises the MBMS scheduling information. In some embodiments, transmitting the third message comprising the MBMS scheduling information further comprises transmitting the MBMS scheduling information to the wireless communication device via a dedicated RRC message by the first DU.

[0018] In some embodiments, receiving the second message further comprises receiving, by the first DU, a system information delivery command from the CU. In some embodiments, transmitting the third message comprising the MBMS scheduling information further comprises transmitting, by the first DU, the MBMS scheduling information to the wireless communication device via a newly defined system information block (SIB).

[0019] Another aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes transmitting a first message to a central unit (CU) of a wireless communication node by a wireless communication device through a first distributed unit (DU) of the wireless communication node. In some embodiments, the first DU corresponds to a first subset of multiple multimedia broadcast multicast service (MBMS) services of the CU. In some embodiments, the first message indicates a second subset of multiple MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method includes performing a switching process from the first DU to the second DU by the wireless communication device. In some embodiments, the method includes receiving a second message including MBMS scheduling information from the CU by the wireless communication device in response to performing the switching process.

[0020] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective identifier.

[0021] In some embodiments, receiving the second message further comprises receiving MBMS scheduling information from the first DU via a dedicated RRC message. In some embodiments, the MBMS scheduling information is transmitted from the CU to the first DU via a newly defined F1 interface message. In some embodiments, receiving the second message further comprises receiving MBMS scheduling information from the first DU via a newly defined system information block (SIB) in response to the first DU receiving a system information transfer command from the CU.

[0022] Another aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes receiving, by a central unit (CU) of a wireless communication node, a first message from a wireless communication device via a first distributed unit (DU) of the wireless communication node. In some embodiments, the first DU corresponds to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, and the first message indicates a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method includes transmitting, by the CU to the wireless communication device, a second message including MBMS scheduling information in response to determining that the wireless communication device has performed a switching process from the first DU to the second DU.

[0023] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective service identifier.

[0024] In some embodiments, transmitting the second message further comprises transmitting, by the CU, a newly defined F1 interface message to the first DU, the message including the MBMS scheduling information, so that the first DU transmits the MBMS scheduling information to the wireless communication device through a dedicated RRC message.

[0025] In some embodiments, the second message further includes transmitting a system information delivery command by the CU to the first DU, so that the first DU transmits the MBMS scheduling information through a newly defined system information block (SIB).

[0026] Another aspect disclosed herein relates to a method for managing multimedia broadcast multicast service (MBMS) continuity. In some embodiments, the method includes receiving a first message from a wireless communication device by a first distributed unit (DU) of a wireless communication node. In some embodiments, the first DU corresponds to a first subset of multiple multimedia broadcast multicast service (MBMS) services of the CU. The first message indicates a second subset of multiple MBMS services corresponding to a second DU of the wireless communication node. In some embodiments, the method includes transmitting a first message to a central unit (CU) of the wireless communication node by the first DU. In some embodiments, the method includes receiving a second message from the DU by the first DU after the wireless communication device performs a switching process from the first DU to the second DU. In some embodiments, the method includes transmitting a third message including MBMS scheduling information to the wireless communication device by the first DU in response to receiving the second message.

[0027] In some embodiments, the first message comprises an MBMSInterestIndication message. In some embodiments, the MBMSInterestIndication message comprises a list of MBMS services that the wireless communication device is receiving and interested in. In some embodiments, each MBMS service is associated with a respective service identifier.

[0028] In some embodiments, receiving the second message further comprises receiving, by the first DU, a newly defined F1 interface message from the CU, which comprises the MBMS scheduling information. In some embodiments, transmitting the third message comprising the MBMS scheduling information further comprises transmitting, by the first DU, the MBMS scheduling information to the wireless communication device via a dedicated RRC message.

[0029] In some embodiments, receiving the second message further comprises receiving, by the first DU, a system information delivery command from the CU. In some embodiments, transmitting the third message comprising the MBMS scheduling information further comprises transmitting, by the first DU, the MBMS scheduling information to the wireless communication device via a newly defined system information block (SIB).

[0030] The above-mentioned aspects and other aspects and embodiments thereof are described in more detail in the drawings, the description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various example embodiments of the present solution are described in detail below with reference to the following drawings. The drawings are provided for illustrative purposes only and only depict example embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered to limit the breadth, scope or applicability of the present solution. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

[0032] Figure 1 An example cellular communication network is shown in which the techniques disclosed herein may be implemented according to one embodiment of the present disclosure.

[0033] Figure 2 A block diagram of example base station and user equipment apparatus according to some embodiments of the present disclosure is shown.

[0034] Figure 3 A block diagram of an example NG-RAN architecture according to some embodiments of the present disclosure is shown.

[0035] Figure 4 A block diagram illustrating an example protocol for an NR-RAN CU-DU split architecture according to some embodiments of the present disclosure is shown.

[0036] Figure 5 A block diagram illustrating an example structure of an internal DU according to some embodiments of the present disclosure.

[0037] Figure 6 A block diagram illustrating an example structure of an inter-DU protocol according to some embodiments of the present disclosure.

[0038] Figure 7 A flow chart of an example measurement process according to some embodiments of the present disclosure is shown.

[0039] Figure 8 A flow chart of an example UE reporting process according to some embodiments of the present disclosure is shown.

[0040] Fig. 9 A flow chart illustrating an example transmission of an MBMS Interest Indication message according to some embodiments of the present disclosure.

[0041] Fig.10 A flow chart illustrating an example successful operation of a UE context setup request procedure according to some embodiments of the present disclosure.

[0042] Fig.11 A flow chart illustrating example unsuccessful operation of a UE context setup request procedure according to some embodiments of the present disclosure.

[0043] Fig.12 A flow chart illustrating an example transmission of an RRC message from a CU to a source DU via an F1 interface according to some embodiments of the present disclosure.

[0044] Fig.13 A flow chart illustrating an example transmission of an RRC message from a source DU to a UE via an air interface according to some embodiments of the present disclosure.

[0045] Fig.14 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown.

[0046] Fig.15 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown, wherein scheduling information is transmitted prior to a handover process.

[0047] Fig.16 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown, wherein scheduling information is transmitted after a handover process.

[0048] Fig.17 A flow chart of an example RRC reconfiguration process according to some embodiments of the present disclosure is shown.

[0049] Fig.18 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown, wherein scheduling information is transmitted prior to a handover process.

[0050] Fig.19 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown, wherein scheduling information is transmitted after a handover process.

[0051] Fig. 20 A table showing a solution (embodiment) for service continuity reception of an RRC_CONNECTED UE according to some embodiments of the present disclosure.

[0052] Fig.21 A flow chart of an example connected UE inter-DU handover process according to some embodiments of the present disclosure is shown, where a dedicated RRC message carries scheduling information.

[0053] Fig. 22 A flow chart of an example connected UE inter-DU handover process according to some embodiments of the present disclosure is shown, where a dedicated RRC message carries scheduling information.

[0054] Fig.23 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure.

[0055] Fig.24 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure.

[0056] Fig.25 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure.

[0057] Fig.26 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure.

[0058] Fig. 27 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure.

[0059] Fig.28 is a flow chart describing a method for managing Multimedia Broadcast Multicast Service (MBMS) continuity according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0060] Various example embodiments of the present solution are described below with reference to the accompanying drawings to enable a person of ordinary skill in the art to make and use the present solution. It will be apparent to a person of ordinary skill in the art that, after reading this disclosure, various changes or modifications may be made to the examples described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged while remaining within the scope of the present solution. Therefore, a person of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or behaviors in a sample order, and unless otherwise expressly stated, the present solution is not limited to the specific order or hierarchy presented.

[0061] The following acronyms are used in this disclosure:

[0062] 3GPP Third Generation Partnership Project

[0063] 5G fifth generation mobile network

[0064] 5G-AN 5G Access Network

[0065] 5G gNB Next Generation Node B

[0066] 5G NR Fifth Generation Mobile Network New Radio

[0067] BMSC Broadcast Multicast / Service Center

[0068] CC Component Carrier

[0069] CGI Cell Global Identifier

[0070] CP Control Plane

[0071] CU Centralized Unit

[0072] DCCH Dedicated Control Channel

[0073] DU Distributed Unit

[0074] eMBMS Enhanced Multimedia Broadcast Service

[0075] EUTRAN Evolved Terrestrial Radio Access Network

[0076] gNB-CU gNB Centralized Unit

[0077] gNB-DU gNB Distributed Unit

[0078] gNB gNodeB

[0079] GPRS General Packet Radio Service

[0080] GTP-U GPRS Tunneling Protocol-User Plane Header

[0081] IP Internet Protocol

[0082] LTE Long Term Evolution

[0083] MAC-CE Media Access Control Element

[0084] MBMS Multimedia Broadcast Service

[0085] MBMS-GW Multimedia Broadcast Multicast Service Gateway

[0086] MBS Mobile Multicast / Broadcast Service

[0087] MCCH Multicast Control Channel

[0088] NG-RAN Next Generation Radio Access Network

[0089] PCI Physical Cell Identifier

[0090] PDCP Packet Data Convergence Protocol

[0091] PDSCH Physical Downlink Shared Channel

[0092] PDU Protocol Data Unit

[0093] RAN Radio Access Network

[0094] RAT Radio Access Technology

[0095] RLC Radio Link Control

[0096] RRC Radio Resource Control

[0097] RSRP Reference Signal Received Power

[0098] RSRQ Reference Signal Received Quality

[0099] SAI Service Area Identifier

[0100] SDAP Service Data Adaptation Protocol

[0101] SDU Service Data Unit

[0102] SIB System Information Block

[0103] SRBI Signal Radio Bearer

[0104] T-PDU Protocol Data Unit

[0105] TMGI Temporary Mobility Group Identifier

[0106] TMGL Temporary Mobile Group Identifier

[0107] TNL Transport Network Layer

[0108] UDP User Datagram Protocol

[0109] UE User Equipment

[0110] UP User Plane

[0111] USD User Service Description

[0112] 1. Mobile communication technology and environment

[0113] Figure 1 An example wireless communication network and / or system 100 is shown in which the techniques disclosed herein may be implemented according to one embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100." Such an example network 100 includes a base station 102 (hereinafter referred to as "BS 102"; also referred to as a wireless communication node) and a user equipment device 104 (hereinafter referred to as "UE 104"; also referred to as a wireless communication device) that may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. In Figure 1 1, BS 102 and UE 104 are contained within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating within its allocated bandwidth to provide adequate radio coverage to its intended users.

[0114] For example, BS 102 may operate with an allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes", which may generally implement the methods disclosed herein. According to various embodiments of the present solution, such communication nodes may be capable of wireless and / or wired communication.

[0115] Figure 2 A block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is shown. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, as described above, the system 200 may be used in a communication environment such as Figure 1 Data symbols are communicated (eg, transmitted and received) in a wireless communication environment of wireless communication environment 100 .

[0116] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled to and interconnected with each other via a data communication bus 220 as needed. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled to and interconnected with each other via a data communication bus 240 as needed. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0117] As will be appreciated by those skilled in the art, the system 200 may also include Figure 2 Any number of modules outside the modules shown. It will be appreciated by those skilled in the art that the various illustrative blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any actual combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are generally described according to their functions. Whether this function is implemented as hardware, firmware, or software may depend on the specific application and design constraints imposed on the entire system. People familiar with the concepts described herein can implement this function in an appropriate manner for each specific application, but this implementation decision should not be interpreted as limiting the scope of the present disclosure.

[0118] According to some embodiments, the UE transceiver 230 may be referred to herein as an "uplink" transceiver 230, which includes a radio frequency (RF) transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time duplex manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a "downlink" transceiver 210, which includes an RF transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 212. The downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time duplex manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuit is coupled to the uplink antenna 232 to receive a transmission over the wireless transmission link 250 at the same time that the downlink transmitter is coupled to the downlink antenna 212. Instead, the operation of the two transceivers 210 and 230 may be coordinated in time such that the downlink receiver coupled to the downlink antenna 212 receives a transmission over the wireless transmission link 250 at the same time that the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization with minimal guard times between changes in duplex direction.

[0119] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and cooperate with an appropriately configured RF antenna arrangement 212 / 232 that can support a specific wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to the application of specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0120] According to various embodiments, for example, BS 202 may be an evolved Node B (eNB), a serving eNB, a target eNB, a femtocell or a microcell. In some embodiments, UE 204 may be implemented in various types of user equipment, such as a mobile phone, a smart phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, a wearable computing device, etc. Processor modules 214 and 236 may be implemented or implemented with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, a separation gate or transistor logic, a discrete hardware component, or any combination thereof (designed to perform the functions described herein). In this manner, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other such configuration.

[0121] In addition, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly embodied in hardware, firmware, software modules executed by the processor modules 214 and 236, respectively, or in any practical combination thereof. The memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 216 and 234 may be coupled to the processor modules 210 and 230, respectively, so that the processor modules 210 and 230 may read information from and write information to the memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during the execution of instructions to be executed by the processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0122] The network communication module 218 generally represents the hardware, software, firmware, processing logic and / or other components of the base station 202 that support bidirectional communication between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a typical deployment, but not limited to, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a traditional Ethernet-based computer network. In this way, the network communication module 218 can include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). The terms "configured for", "configured to" and their variations used herein with respect to a specific operation or function refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and / or arranged to perform a specific operation or function.

[0123] The Open Systems Interconnection (OSI) model (referred to herein as the "Open Systems Interconnection Model") is a concept and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnect and communicate with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual set of services provided to the layers above and below it. The OSI model also defines a logical network and effectively describes computer packet delivery by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or a seven-layer model. In some embodiments, the first layer may be a physical layer. In some embodiments, the second layer may be a media access control (MAC) layer. In some embodiments, the third layer may be a radio link control (RLC) layer. In some embodiments, the fourth layer may be a packet data convergence control (PDCL) layer. In some embodiments, the fifth layer may be a radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer is another layer.

[0124] 2. Overview of Multimedia Broadcast and Multicast Services

[0125] MBMS (Multimedia Broadcast Multicast Service) is a point-to-multipoint interface specification for 3GPP cellular networks. Providing efficient broadcast and multicast services in cellular and core networks is the cornerstone of mobile TV services. For broadcast transmission across cellular lines, MBMS defines the transmission mode using a single frequency network configuration. As mobile communications enter the LTE stage, MBMS technology has evolved into eMBMS (enhanced Multimedia Broadcast Multicast Service) in 4G communications to meet the growing business needs.

[0126] Enhanced Multimedia Broadcast Service (eMBMS) can provide users with personalized, customized and various data services in the form of text, images, audio and video. For mobile data service bearers, the biggest advantage of eMBMS is that it can save air interface resources and reduce network operating costs when there are more user business needs in the service area. It has two modes: broadcast hosting and multicast hosting. Broadcast hosting is suitable for live broadcast, government emergency information and multimedia advertising push scenarios. Multicast hosting is suitable for customized content needs, such as VOD and download.

[0127] Depending on different service activities, a user equipment (UE) receiving MBMS services can be in one of the following three RRC states: radio resource control (RRC) connected state (RRC_CONNECTED), RRC_IDLE (RRC idle state) and RRC_Inactive (RRC inactive state). In the RRC_CONNECTED state, the RRC context has been established and all parameters required for communication between the terminal and the radio access network are known. In the RRC_IDLE state, there is no RRC context in the radio access network - that is, there are no parameters for communication between the terminal and the network. At this time, the terminal does not belong to any cell. In the RRC_INACTIVE state, the RRC context is saved in the terminal and the base station. Another important difference between the different states is the related mobility mechanism. For UEs in idle and inactive states, mobility is handled by the UE through cell reselection. For UEs in connected mode, mobility is managed by the radio access network, which means that the network side plays a leading role in handover decisions and target cell selection. The measurement report and other information reported by the UE are used as a reference for the source eNodeB to make handover decisions.

[0128] In a multi-frequency LTE network, eMBMS services can be provided over multiple frequencies. In the 3GPP R11 version of the standard, content to support eMBMS service continuity can be added. By obtaining information in SIB15 on PDSCH (Physical Downlink Shared Channel), the user equipment (UE) can understand the frequency and location of the service of interest, and can guide the UE to find the service of interest on other frequencies. SIB 15 can contain a list of IDs (e.g., service area identifier (SAI)) of the MBMS service area where the current service frequency is located, a list of adjacent frequencies for MBMS services and corresponding MBMS SAIs, and / or a list of MBMS SAIs for specific frequencies.

[0129] When an LTE UE in idle state enters an overlapping area of ​​eNodeB coverage and needs to be handed over, the UE can determine the target cell based on the measurement results. In order to avoid delays caused by reading relevant eMBMS information on adjacent frequencies on SIB 13 and MCCH messages, the network can combine the User Service Description (USD) information and SIB 15 information to provide the UE with eMBMS services provided on different frequencies. In USD, each service has its service identifier (service identifier), including TMGI (temporary mobile group identifier) ​​and / or MBMS service area and frequency of SAI. SIB 15 may contain a list that contains the current frequency and / or adjacent frequencies. Each frequency may contain a list of some or all SAIs supported by the frequency. By combining information about USD and SIB15, the UE can find the frequency on which it can provide its current service or the service it is interested in.

[0130] The information obtained from USD and SIB 15 is very important. When the UE leaves the cell idle, the UE can switch to a cell that can provide the required eMBMS service frequency according to the priority. In this way, as long as the UE provides the required service in the adjacent frequency, the eMBMS service continuity can be maintained.

[0131] In the RRC_CONNECTED state, a UE receiving an eMBMS service or being interested in an eMBMS service may send a measurement report and / or an RRC message (MBMS InterestIndicator) in response to a SIB 15 message. The message may contain a frequency list of eMBMS services that the UE is currently receiving or interested in, and / or contain a feature bit that notifies the current cell that the UE wants to receive an eMBMS service or a unicast service. The current eNodeB can select a target cell for the UE through this information. A candidate cell that can provide appropriate eMBMS services on any frequency may be at the highest priority for that frequency. When the cell is considered a target cell, the UE can continue to receive services of interest from that frequency.

[0132] 3. UE handover type in RRC_CONNECTED state

[0133] The handover type of a UE in the RRC_CONNECTED state can be divided into two different types: (1) handover based on radio access technology (RAT) coverage and (2) handover based on carrier frequency.

[0134] 3.1 Handover based on radio access technology (RAT) coverage

[0135] This type may include intra-system handover (intra-NR), which includes intra-gNB handover (e.g., handover between two cells under the same gNB) and / or inter-gNB handover (e.g., handover between two cells under different gNBs).

[0136] This type may include inter-system handover (inter-RAT), which includes handover between 5G NR and other systems.

[0137] 3.2 Switching based on carrier frequency

[0138] This type can include intra-frequency handover and inter-frequency handover.

[0139] 4. Logical architecture of 5G New Radio (NR) gNB

[0140] For 5G stand-alone (SA) deployment, the logical architecture of gNB adopts the separation of centralized unit (CU) and distributed unit (DU).

[0141] Figure 3 A block diagram of an example NG-RAN architecture according to some embodiments of the present disclosure is shown. Environment 300 includes 5GC 302 and NG-RAN 304. NG-RAN 304 includes gNB 306A and gNB 306B. In some embodiments, each gNB 306A, 306B may be a wireless communication node, such as Figure 1 BS 102 in.

[0142] gNB 306A includes gNB-CU 308A ( Figure 3 Not shown), gNB-DU 310A ( Figure 3 ) and gNB-DU312A ( Figure 3 ). gNB-DU 310A and gNB-DU 312A are connected to gNB-CU 308A via the F1 logical interface.

[0143] gNB 306B includes gNB-CU 308B, gNB-DU 310B and gNB-DU 312B. gNB-DU 310B and gNB-DU312B are connected to gNB-CU 308B via an F1 logical interface.

[0144] although Figure 3 In the figure, each gNB 306A, 306B is shown to include only one gNB-CU and two gNB-DUs, but each gNB 306A, 306B may include any number of gNB-CUs and two gNB-DUs. The environment 300 may also include any number of NG-RANs 304.

[0145] The gNB-CU and gNB-DU are separated according to the real-time requirements of different protocol layers. Under this principle, the physical layer, MAC layer, and RLC layer with high real-time requirements are processed in the DU, while the PDCP layer and SDAP layer with low real-time requirements are processed in the CU.

[0146] Figure 4 A block diagram of an example protocol for an NR-RAN CU-DU split architecture according to some embodiments of the present disclosure is shown. That is, Figure 4 The protocol stacks of the user plane and the control plane of the NG-RAN CU-DU split architecture are shown. The environment 400 includes a gNB 402A associated with a UP (user plane) function and a gNB 402B associated with a CP (control plane) function. In some embodiments, each gNB 402A, 402B can be a wireless communication node, such as Figure 1 BS 102 in.

[0147] The gNB 402A includes a CU 404A and a DU 408A. The CU 404A includes a protocol stack 406A consisting of an SDAP layer and a PDCP layer. The DU 408A includes a protocol stack 410A, which includes an RLC layer, a MAC layer, and a PHY layer. The CU 404A is connected to the DU 408A via an F1 logical interface.

[0148] The gNB 402B includes a CU 404B and a DU 408B. The CU 404B includes a protocol stack 406B consisting of an RRC layer and a PDCP layer. The DU 408B includes a protocol stack 410B consisting of an RLC layer, a MAC layer, and a PHY layer. The CU 404B is connected to the DU 408B via an F1 logical interface.

[0149] Figure 5 5 shows a block diagram of an example structure of an internal DU according to some embodiments of the present disclosure. Environment 500 includes a DU 502A ( Figure 5 DU 1) and DU 502B ( Figure 5 CU 502 (shown as “DU 2” in FIG. 2 ).

[0150] DU 502A connected to CF 504A ( Figure 5 CF 506A ( Figure 5 CF 508A ( Figure 5 CF3) until CF 510A ( Figure 5 That is, DU 502A can be connected to any number of CFs.

[0151] DU 502B is connected to CF 504B ( Figure 5 CF 506B ( Figure 5 CF 508B ( Figure 5 CF3) until CF 510B ( Figure 5 That is, DU 502B can be connected to any number of CFs.

[0152] Figure 6 600 includes a DU 604 ( Figure 6 and a protocol stack 602 connected to DU 606 (shown as "DU 1") via an F1 logical interface. Figure 6 6 (shown as “DU 2” in FIG. 6 ).

[0153] DU 604 includes a protocol stack consisting of an SDAP layer and a PDCP layer. DU 606 includes a protocol stack consisting of an RLC layer, a MAC layer, and a PHY layer.

[0154] refer to Figure 5 and Figure 6 For the NG RAN CU-DU separation architecture, UE mobility is divided into two categories: inter-CU mobility (referred to herein as "inter-CU mobility") and mobility within the same CU (referred to herein as "intra-DU mobility"). The scope of application of this patent regarding service continuity guarantee for broadcast and multicast is cell switching within the same CU. The specific expansion structure is as follows Figure 5 As shown in A. Each DU has several carrier frequencies (cfX), each of which corresponds to a cell.

[0155] 4. UE reporting process-MeasurementReport message

[0156] Figure 7 1 shows a flow chart of an example measurement process according to some embodiments of the present disclosure. The measurement process involves UE 702 (eg, Figure 1 Communication between UE 102) and CU 704.

[0157] If UE 702 detects that the measurement result meets the triggering condition of the measurement event, it generates a measurement report and reports it to CU 704. The measurement report message is carried by the MeasurementReport message, which is an RRC message. The message contains one or more of the following measurement results: measurement report ID, PCI, CGI and RSRP&RSRQ.

[0158] Before UE 702 sends a measurement report, CU 704 sends a measurement configuration. After receiving the measurement configuration, UE 702 performs measurement according to the detailed measurement configuration.

[0159] 5. UE reporting process - MBMSInterestIndication message

[0160] The MBMSInterestIndication message is sent by the UE (eg, Figure 1 UE 102 in the example) is sent to the CU (e.g., Figure 7 CU 704 in the UE, notifying the UE of the MBMS service being received or interested. The message contains a list of services that the UE is receiving or interested in (e.g., ServicesListMBMS). Each service is uniquely identified by a TMGI.

[0161] The configuration of the MBMSInterestIndication message and the related IEs included are as follows:

[0162] MBMSInterestIndication message

[0163] Signaling Radio Bearer: SRB1

[0164] RLC-SAP:AM

[0165] Logical channel: DCCH

[0166] Direction: UE to CU

[0167]

[0168]

[0169] Figure 8 800 includes a UE 802 (e.g., Figure 1 UE 102 in ), source DU 804, target DU 806 and CU 808.

[0170] When the measurement result meets the triggering condition of the measurement event or the UE 102 changes its MBMS service of interest, the MBMSInterestIndication message and the measurement report are simultaneously forwarded to the CU 808 via the source DU 804 through the F1 interface, such as Figure 8 As shown. In response, the source DU 804 sends a measurement report and an MBMSInterestIndication message to the CU 808 via UL RRC message transmission.

[0171] Fig. 9Flowchart 900 shows an example transmission of an MBMSInterestIndication message according to some embodiments of the present disclosure. Flowchart 900 includes UE 102 and EUTRAN 904. UE 902 sends an MBMSInterestIndication message (also referred to as SIB15) in response to receiving SIB15 from EUTRAN 904. Figure 7 Therefore, when the cell does not broadcast SIB 15, UE 902 will not send the MBMS Interest Indication message.

[0172] 6. Target cell selection

[0173] The CU determines the target cell for UE handover based on the reported measurement report (e.g., MeasurementReport message) and MBMS interest indication (e.g., MBMSInterestIndicatio message). The decision process is as follows:

[0174] In the first operation, the source cell lists the priority order of the target cells according to the UE measurement report and the MBMS interest indication.

[0175] In the second operation, a target cell that meets the signal quality requirement is selected as a candidate cell.

[0176] In a third operation, a cell is selected from candidate cells supporting the MBMS service that the UE is receiving or interested in according to a priority order. This cell is a target cell.

[0177] In a fourth operation, if the candidate cells cannot provide the MBMS service that the UE is receiving or interested in, a cell with the highest priority is selected as the target cell.

[0178] 7. UE context setting and management

[0179] Fig.10 A flow chart illustrating an example successful operation of a UE context setup request procedure according to some embodiments of the present disclosure. Flowchart 1000 includes a target DU 1002 and a CU 1004 communicating with each other via an F1 interface.

[0180] Fig.11 A flow chart illustrating an example unsuccessful operation of a UE context setup request procedure according to some embodiments of the present disclosure. Flowchart 1100 includes a target DU 1102 and a CU 1104 communicating with each other via an F1 interface.

[0181] refer to Fig.10 and Fig.11, the purpose of the UE context setup procedure is to request the target DU 1002, 1102 to establish a UE context and a multicast data bearer or one or more unicast data bearers. The CU 1004, 1104 initiates the procedure by sending a UE context setup request message to the target DU 1002, 1102. If the target DU 1002, 1102 successfully establishes the UE context, it replies to the CU 1004, 1104 with a UE context setup response message. If the target DU 1002, 1102 cannot establish the F1 UE context, or even cannot establish one bearer, the procedure shall be considered as a failure and replied with a UE context setup failure message.

[0182] The UE Context Setup Request message also contains HandoverPreparationInformation (in the CU to DU RRC Information IE). The RRC information may include mobility control, radio resource configuration (including RB, MAC primary configuration and physical channel configuration) and AS security configuration.

[0183] 8. MBMS scheduling information transmission

[0184] The purpose of scheduling information transmission is for the CU to inform the UE in the target cell of the radio resource configuration of the MBMS service. The present disclosure provides two feasible solutions for the CU to deliver scheduling information to the UE.

[0185] 8.1 Carrying MBMS Scheduling Information in Dedicated RRC Messages

[0186] Fig.12 12 shows a flow chart of an example transmission of an RRC message from a CU to a source DU via an F1 interface according to some embodiments of the present disclosure. Flowchart 1200 includes a source DU 1202 and a CU 1204 communicating with each other via an F1 interface. Fig.12 As shown, the RRC message carrying the scheduling information may be sent to the source DU 1202 on the F1 interface via a new F1 interface message (eg, MBMS scheduling information).

[0187] Fig.13 1300 includes a UE 1302 (e.g., Figure 1 UE 102 in ) and source DU 1304. Fig.13 As shown, source DU 1304 may send MBMS scheduling information to UE 1302 carried in a dedicated RRC message.

[0188] 8.2 Carrying MBMS Scheduling Information in New SIB Messages

[0189] MBMS scheduling information is carried by a new SIB message and broadcast to UEs (e.g. Figure 1 UE 102 in ).

[0190] Fig.14 A flow chart of an example system information transfer process according to some embodiments of the present disclosure is shown. Flowchart 1400 includes CU 1406 communicating with source DU 1404 via an F1 interface. Flowchart 1400 also includes UE 102 communicating with source DU 1404 via a radio interface. The transmission of SIB messages on the F1 interface is performed through the system information transfer process. The purpose of the system information transfer process is to command the source DU 1404 to broadcast the SIB carrying MBMS scheduling information.

[0191] The CU 1406 initiates the process by sending a system information transfer command message to the source DU 1404 .

[0192] 8.3 Opportunity to send scheduling information

[0193] The opportunity to send scheduling information greatly affects the service continuity of the UE, which in turn directly affects the final user experience. The present disclosure provides two possible opportunities to send scheduling information (e.g., Fig.15 and Fig.16 shown).

[0194] As a first opportunity, Fig.15 A flow chart of an example system information transfer process is shown, wherein scheduling information is transmitted prior to a handover process, in accordance with some embodiments of the present disclosure. Flowchart 1500 includes a UE 1502, a source DU 1504, a target DU 1506, and a CU 1508.

[0195] That is, before the RRCReconfiguration message is forwarded from the source DU 1504 to the UE 1502, the transmission of the scheduling information is completed before the UE 1502 is handed over to the target cell. In this way, after the UE 1502 is handed over to the target cell, it can immediately receive the broadcast multicast data, resulting in seamless continuous service reception. For example, the CU 1508 sends a new F1 interface message to the source DU 1504. In response, the source DU 1504 sends a dedicated RRC message to the UE 1502.

[0196] As a second chance, Fig.16 A flow chart of an example system information transfer process is shown, wherein scheduling information is transmitted after a handover process, in accordance with some embodiments of the present disclosure. Flowchart 1600 includes UE 1602, source DU 1604, target DU 1606, and CU 1608.

[0197] That is, the transmission of the MBMS scheduling information (new F1 interface message) is after the UE 1602 is handed over to the target cell, for example, after receiving the RRCReconfigurationComplete message from the target DU 1606 through UL RRC message transmission. However, this time may cause a large interruption time for service reception. In order to alleviate and / or avoid such a large interruption time, after the UE 1602 is handed over to the target cell, it should wait for a period of time before receiving broadcast / multicast data.

[0198] 9. RRC reconfiguration process

[0199] Fig.17 A flow chart of an example RRC reconfiguration process according to some embodiments of the present disclosure is shown. Flowchart 1700 includes US 1702, source DU 1704, target DU 1706, and CU 1708.

[0200] The process of RRC reconfiguration is a process of configuration by CU 1708 and confirmation by UE 1702. CU 1708 transmits a UE Context Modification Request message over the F1 interface to transmit the RRC reconfiguration information to the source DU 1704, and forwards it to UE 1702 via a dedicated RRC message. In response, UE 1702 returns an RRCReconfigurationComplete message to the target cell to confirm that the RRC connection reconfiguration is successfully completed. The UL RRC message transmission message is used to forward it to CU 1708 on the F1 interface.

[0201] 10. Methods for managing 5G MBMS continuity

[0202] Fig.18 A flow chart of an example system information transfer process is shown, wherein scheduling information is transmitted prior to a handover process, in accordance with some embodiments of the present disclosure. Flowchart 1800 includes a UE 1802 , a source DU 1804 , a target DU 1806 , and a CU 1808 .

[0203] like Fig.18As shown, the scheduling information is sent before the handover. That is, UE 1802, source DU 1804, target DU 1806 and / or CU 1808 can communicate (send / receive) UE reports to each other. Target DU 1806 and / or CU 1808 can establish UE context. UE 1802, source DU 1804, target DU 1806 and / or CU 1808 can communicate (send / receive) MBMS scheduling information to each other (via RRC dedicated message / SIB). UE 1802, source DU 1804, target DU 1806 and / or CU 1808 can modify UE context. UE 1802, source DU 1804, target DU 1806 and / or CU 1808 can reconfigure RRC.

[0204] Fig.19 A flow chart of an example system information transfer process is shown, wherein scheduling information is transmitted after a handover process, according to some embodiments of the present disclosure. Flowchart 1900 includes UE 1902, source DU 1904, target DU 1906, and CU 1908.

[0205] UE 1902, source DU 1904, target DU 1906 and / or CU 1908 may communicate (send / receive) UE reports to each other. Target DU 1906 and / or CU 1908 may establish UE context. UE 1902, source DU 1904, target DU 1906 and / or CU 1908 may modify UE context. UE 1902, source DU 1904, target DU 1906 and / or CU 1908 may reconfigure RRC. UE 1902, source DU 1904, target DU 1906 and / or CU 1908 may communicate (send / receive) MBMS scheduling information to each other (via RRC dedicated message / SIB).

[0206] Fig. 20 A solution (embodiment) table for service continuity reception for RRC_CONNECTED UE according to some embodiments of the present disclosure is shown. That is, Table 2000 shows a solution (embodiment) for implementing service continuity reception for UE in a connected state based on the opportunity of sending scheduling information and the manner of carrying MBMS scheduling information (e.g., a dedicated RRC message or a new SIB).

[0207] Fig.21 A flow chart of an example connected UE inter-DU handover process is shown, wherein a dedicated RRC message carries scheduling information, according to some embodiments of the present disclosure. Flowchart 2100 includes UE 2102, source DU 2104, target DU 2106, and CU 2108.

[0208] UE 2102 sends a measurement report and an MBMS interest indication to source DU 2104. Source DU 2104 sends a measurement report and an MBMS interest indication to CU 2108. CU 2108 sends a UE context setup request to target DU 2106. Target DU 2106 sends a UE context setup response and / or a fault message to CU 2108. CU 2108 sends a new F1 interface message to source DU 2104. Source DU 2104 sends a dedicated RRC message to UE 2102. CU 2108 sends a UE context modification request to source DU 2104. Source DU 2104 sends a downlink data delivery status to CU 2108. Source DU 2104 sends an RRC reconfiguration to UE 2102. Source DU 2104 sends a UE context modification response to CU 2108. UE 2102 and / or target DU 2106 perform a random access procedure. UE 2102 sends an RRC reconfiguration complete message to target DU 2106. Target DU 2106 sends an RRC reconfiguration complete message to CU 2108. CU 2108 sends a new F1 interface message to source DU 2104. Source DU 2104 sends a dedicated RRC message to UE 2102.

[0209] Fig. 22 A flow chart of an example connected UE inter-DU handover process according to some embodiments of the present disclosure is shown, where a dedicated RRC message carries scheduling information. Flowchart 2200 includes UE 2202, source DU 2204, target DU 2206, and CU 2208. Based on inter-gNB-DU unicast mobility, flow chart 2200 provides supplementary information about interactive messages and flows in broadcast / multicast service scenarios.

[0210] UE 2202 sends a measurement report and an MBMS interest indication to source DU 2204. Source DU 2204 sends a measurement report and an MBMS interest indication to CU 2208. CU 2208 sends a UE context setup request to target DU 2206. Target DU 2206 sends a UE context setup response and / or a fault message to CU 2208. CU 2208 sends a system information transfer command to source DU 2204. Source DU 2204 sends a new SIB message to UE 2202. CU 2208 sends a UE context modification request to source DU 2204. Source DU 2204 sends a downlink data delivery status to CU 2208. Source DU 2204 sends an RRC reconfiguration to UE 2202. Source DU 2204 sends a UE context modification response to CU 2208. UE 2202 and / or target DU 2206 perform a random access procedure. UE 2202 sends an RRC reconfiguration complete message to target DU 2206. Target DU 2206 sends an RRC reconfiguration complete message to CU 2208. CU 2208 sends a system information transfer command message to source DU 2204. Source DU 2204 sends a dedicated RRC message to UE 2202.

[0211] Fig.23 is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2300 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2300 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0212] As shown, method 2300 includes an operation 2302 in which a wireless communication device transmits a first message to a central unit (CU) of a wireless communication node through a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, and the first message indicates a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2300 includes an operation 2304 in which the wireless communication device receives a second message including MBMS scheduling information from the CU in response to transmitting the first message. Method 2300 includes an operation 2306 in which the wireless communication device performs a switching process from the first DU to the second DU.

[0213] Fig.24is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2400 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2400 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0214] As shown, method 2400 includes an operation 2402 of receiving a first message from a wireless communication device by a central unit (CU) of a wireless communication node through a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast services (MBMS) services of the CU, and the first message indicating a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2400 includes an operation 2404 of transmitting a second message including MBMS scheduling information to the wireless communication device by the CU in response to receiving the first message. Method 2400 includes an operation 2406 of causing the wireless communication device to perform a switching process from the first DU to the second DU.

[0215] Fig.25 is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2500 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2500 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0216] As shown, method 2500 includes an operation 2502 of receiving a first message from a wireless communication device by a first distributed unit (DU) of a wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of a CU, and the first message indicating a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2500 includes an operation 2504 of transmitting the first message to a central unit (CU) of the wireless communication node by the first DU. Method 2500 includes an operation 2506 of receiving a second message from the DU by the first DU. Method 2500 includes an operation 2508 of transmitting a third message including MBMS scheduling information to the wireless communication device by the first DU in response to receiving the second message, which causes the wireless communication device to perform a switching process from the first DU to the second DU.

[0217] Fig.26 is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2600 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2600 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0218] As shown, method 2600 includes an operation 2602 in which a wireless communication device transmits a first message to a central unit (CU) of a wireless communication node through a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, and the first message indicates a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2600 includes an operation 2604 in which the wireless communication device performs a switching process from the first DU to the second DU. Method 2600 includes an operation 2606 in which the wireless communication device receives a second message including MBMS scheduling information from the CU in response to performing the switching process.

[0219] Fig. 27 is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2700 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2700 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0220] As shown, method 2700 includes an operation 2702 of receiving, by a central unit (CU) of a wireless communication node, a first message from a wireless communication device via a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, and the first message indicating a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2700 includes an operation 2704 of transmitting, by the CU to the wireless communication device, a second message including MBMS scheduling information in response to determining that the wireless communication device has performed a handover process from the first DU to the second DU.

[0221] Fig.28 is a flow chart describing a method for managing multimedia broadcast multicast service (MBMS) continuity according to some embodiments of the present disclosure. Depending on the particular embodiment, additional, fewer, or different operations may be performed in the method. In some embodiments, some or all of the operations of method 2800 may be performed by a wireless communication node (e.g., Figure 1 In some operations, some or all of the operations of method 2800 may be performed by a wireless communication device (e.g., Figure 1 Each operation may be reordered, added, deleted, or repeated.

[0222] As shown, method 2800 includes an operation 2802 in which a first distributed unit (DU) of a wireless communication node receives a first message from a wireless communication device, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of a CU, and the first message indicates a second subset of a plurality of MBMS services corresponding to a second DU of the wireless communication node. Method 2800 includes an operation 2804 in which the first DU transmits the first message to a central unit (CU) of the wireless communication node. Method 2800 includes an operation 2806 in which the first DU receives a second message from the DU, and then the wireless communication device performs a switching process from the first DU to the second DU. Method 2800 includes an operation 2808 in which the first DU transmits a third message including MBMS scheduling information to the wireless communication device in response to receiving the second message.

[0223] Although various embodiments of the present solution have been described above, it should be understood that they are presented by way of example only and not by way of limitation. Similarly, various figures may depict exemplary architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present solution. However, these persons should understand that the present solution is not limited to the exemplary architectures or configurations shown, but may be implemented using various alternative architectures and configurations. In addition, as will be appreciated by those of ordinary skill in the art, one or more features of an embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

[0224] It should also be understood that any reference to an element using names such as "first," "second," etc., herein does not generally limit the number or order of these elements. Rather, these names may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to a first and a second element does not mean that only two elements may be used, or that the first element must precede the second element in some manner.

[0225] In addition, those skilled in the art will appreciate that any of a variety of different technologies and techniques may be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, and symbols, etc., that may be referenced in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0226] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, devices, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of both), firmware, various forms of programs or design codes containing instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies. In order to clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above with respect to their functions. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the specific application and design constraints imposed on the overall system. A skilled technician may implement the described functionality in various ways for each specific application, but such implementation decisions will not result in a departure from the scope of the present disclosure.

[0227] In addition, it will be understood by those of ordinary skill in the art that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented or performed within an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may also include antennas and / or transceivers to communicate with various components within a network or within a device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor), multiple microprocessors, one or more microprocessors combined with a DSP core, or any other suitable configuration for performing the functions described herein.

[0228] If implemented in software, these functions can be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, which include any media that can be enabled to transfer a computer program or code from one place to another. The storage medium can be any available medium that a computer can access. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0229] In this application, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various modules are described as discrete modules; however, as is apparent to those of ordinary skill in the art, two or more modules may be combined to form a single module that performs the relevant functions of an embodiment of the present solution.

[0230] In addition, in the embodiment of the present solution, memory or other memory and communication components can be used. It should be understood that, for the sake of clarity, the above description describes the embodiment of the present solution with reference to different functional units and processors. However, it is obvious that any appropriate functional distribution between different functional units, processing logic elements or domains can be used without departing from the present solution. For example, the function illustrated as being performed by a separate processing logic element or controller can be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is only a reference to an appropriate device for providing the function, rather than indicating a strict logical or physical structure or organization.

[0231] Various modifications to the embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the broadest scope consistent with the novel features and principles disclosed herein, as described in the following claims.

Claims

1. A wireless communication method, comprising: transmitting, by a wireless communication device, a first message to a central unit (CU) of a wireless communication node via a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; In response to transmitting the first message, receiving, by the wireless communication device from the CU, a second message including MBMS scheduling information; as well as A handover process from the first DU to the second DU is performed by the wireless communication device.

2. The wireless communication method according to claim 1, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective service identifier.

3. The wireless communication method according to claim 1, wherein: Receiving the second message further includes: receiving the MBMS scheduling information from the first DU via a dedicated RRC message, The MBMS scheduling information is transmitted from the CU to the first DU via a newly defined F1 interface message.

4. The wireless communication method according to claim 1, wherein: Receiving the second message further includes: In response to the first DU receiving a system information delivery command from the CU, the MBMS scheduling information is received from the first DU via a newly defined system information block (SIB).

5. A wireless communication method, comprising: receiving, by a central unit (CU) of a wireless communication node from a wireless communication device via a first distributed unit (DU) of the wireless communication node, a first message corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; In response to receiving the first message, transmitting, by the CU to the wireless communication device, a second message including MBMS scheduling information; as well as The wireless communication device is caused to perform a handover process from the first DU to the second DU.

6. The wireless communication method according to claim 5, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective service identifier.

7. The wireless communication method according to claim 5, wherein: Transmitting the second message further includes: The CU transmits a newly defined F1 interface message including the MBMS scheduling information to the first DU, so that the first DU transmits the MBMS scheduling information to the wireless communication device via a dedicated RRC message.

8. The wireless communication method according to claim 5, wherein: Transmitting the second message further includes: A system information delivery command is transmitted by the CU to the first DU, so that the first DU transmits the MBMS scheduling information via a newly defined system information block (SIB).

9. A wireless communication method, comprising: receiving, by a first distributed unit (DU) of a wireless communication node from a wireless communication device, a first message, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of a central unit (CU) of the wireless communication node, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; Transmitting the first message to the CU by the first DU; receiving, by the first DU, a second message from the CU; as well as In response to receiving the second message, the first DU transmits a third message including MBMS scheduling information to the wireless communication device, so that the wireless communication device performs a switching process from the first DU to the second DU.

10. The wireless communication method according to claim 9, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective service identifier.

11. The wireless communication method according to claim 9, wherein: Receiving the second message further includes: The first DU receives a newly defined F1 interface message including the MBMS scheduling information from the CU, and wherein transmitting a third message including the MBMS scheduling information further comprises: The MBMS scheduling information is transmitted by the first DU to the wireless communication device via a dedicated RRC message.

12. The wireless communication method according to claim 9, wherein: Receiving the second message further includes: The first DU receives a system information delivery command from the CU, and wherein transmitting a third message including MBMS scheduling information further comprises: The MBMS scheduling information is transmitted by the first DU to the wireless communication device via a newly defined system information block (SIB).

13. A wireless communication method, comprising: transmitting, by a wireless communication device, a first message to a central unit (CU) of a wireless communication node via a first distributed unit (DU) of the wireless communication node, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; performing, by the wireless communication device, a handover process from the first DU to the second DU; as well as In response to performing the handover procedure, a second message including MBMS scheduling information is received by the wireless communication device from the CU.

14. The wireless communication method according to claim 13, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective identifier.

15. The wireless communication method according to claim 13, wherein: Receiving the second message further includes: receiving the MBMS scheduling information from the first DU via a dedicated RRC message, The MBMS scheduling information is transmitted from the CU to the first DU via a newly defined F1 interface message.

16. The wireless communication method according to claim 13, wherein: Receiving the second message further includes: In response to the first DU receiving a system information delivery command from the CU, the MBMS scheduling information is received from the first DU via a newly defined system information block (SIB).

17. A wireless communication method, comprising: receiving, by a central unit (CU) of a wireless communication node from a wireless communication device via a first distributed unit (DU) of the wireless communication node, a first message corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of the CU, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; as well as In response to determining that the wireless communication device has performed a handover procedure from the first DU to the second DU, a second message including MBMS scheduling information is transmitted by the CU to the wireless communication device.

18. The wireless communication method according to claim 17, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective service identifier.

19. The wireless communication method according to claim 17, wherein: Transmitting the second message further includes: The CU transmits a newly defined F1 interface message including the MBMS scheduling information to the first DU, so that the first DU transmits the MBMS scheduling information to the wireless communication device via a dedicated RRC message.

20. The wireless communication method according to claim 17, wherein: Transmitting the second message further includes: A system information delivery command is transmitted by the CU to the first DU, so that the first DU transmits the MBMS scheduling information via a newly defined system information block (SIB).

21. A wireless communication method, comprising: receiving, by a first distributed unit (DU) of a wireless communication node from a wireless communication device, a first message, the first DU corresponding to a first subset of a plurality of multimedia broadcast multicast service (MBMS) services of a central unit (CU) of the wireless communication node, the first message indicating a second subset of the plurality of MBMS services corresponding to a second DU of the wireless communication node; Transmitting the first message to the CU by the first DU; Before the wireless communication device performs a handover process from the first DU to the second DU, receiving, by the first DU, a second message from the CU; as well as In response to receiving the second message, a third message including MBMS scheduling information is transmitted by the first DU to the wireless communication device.

22. The wireless communication method according to claim 21, wherein: The first message includes an MBMSInterestIndication message, wherein the MBMSInterestIndication message includes a list of MBMS services that the wireless communication device is currently receiving and is interested in, each MBMS service being associated with a respective service identifier.

23. The wireless communication method according to claim 21, wherein: Receiving the second message further includes: The first DU receives a newly defined F1 interface message including the MBMS scheduling information from the CU, and wherein transmitting a third message including the MBMS scheduling information further comprises: The MBMS scheduling information is transmitted by the first DU to the wireless communication device via a dedicated RRC message.

24. The wireless communication method according to claim 21, wherein: Receiving the second message further includes: The first DU receives a system information delivery command from the CU, and wherein transmitting a third message including MBMS scheduling information further comprises: The MBMS scheduling information is transmitted by the first DU to the wireless communication device via a newly defined system information block (SIB).

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