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CN-122003950-A - System and method for managing state transitions of multicast UEs in a wireless communication system

CN122003950ACN 122003950 ACN122003950 ACN 122003950ACN-122003950-A

Abstract

The present disclosure relates to fifth generation (5G) or sixth generation (6G) communication systems for supporting higher data transmission rates. A method and system for managing state transitions of Multicast Broadcast Service (MBS) User Equipment (UE) 102, managing service continuity for the multicast UE 102, and managing Packet Data Convergence Protocol (PDCP) synchronization for the multicast UE 102 in a wireless network are provided. A Radio Resource Control (RRC) connection recovery procedure is initiated when a point-to-multipoint (PTM) configuration is not available in the cell after cell selection and/or cell reselection and the UE 102 has at least one active session in an rrc_inactive state. The RRC connection recovery procedure is also initiated when the cell after cell selection and/or cell reselection is an MBS control channel free (MCCH) cell and the UE 102 has at least one active session (e.g., is instructed to monitor G-RNTI) in the rrc_inactive state. Furthermore, by providing a mechanism for multicast reception across cells in a Radio Access Network (RAN) notification area (RNA), multicast MRBs are handled during mobility, with or without PDCP synchronization indicated in the multicast session.

Inventors

  • V.K. SRIVASTAVA
  • BAI XIANGGUI
  • S. RAJENDRAN

Assignees

  • 三星电子株式会社

Dates

Publication Date
20260508
Application Date
20240925
Priority Date
20230929

Claims (15)

  1. 1. A method performed by a User Equipment (UE) in a wireless communication system, the method comprising: receiving a Radio Resource Control (RRC) release message including Multicast Broadcast Service (MBS) configuration information from a Base Station (BS), wherein the MBS multicast configuration is associated with receiving MBS multicast in an RRC inactive state; performing cell selection of a cell, and In case the UE is not instructed to stop monitoring a group radio network temporary identifier (G-RNTI) of the multicast session the UE has joined for the cell, performing an RRC connection recovery procedure.
  2. 2. The method according to claim 1, Wherein in case a point-to-multipoint (PTM) configuration for the multicast session is not available in said cell, an RRC connection recovery procedure is performed, Wherein the PTM configuration is included in the MBS configuration information.
  3. 3. The method of claim 1, further comprising: system information block 1 (SIB 1) is received on the cell, Where SIB1 does not schedule SIB24, an RRC connection recovery procedure is performed, Wherein SIB24 is associated with MBS reception in the cell in RRC inactive state.
  4. 4. The method of claim 1, further comprising: receiving a paging message from the BS, the paging message including configuration information regarding receipt of MBS multicast in an RRC inactive state for a multicast session, and Monitor a G-RNTI corresponding to a Temporary Mobile Group Identity (TMGI) included in the paging message, Wherein in case that an MBS Control Channel (MCCH) for a multicast session indicated by a TMGI does not exist in the cell, an RRC connection restoration procedure is performed.
  5. 5. The method according to claim 1, Wherein the cell is different from the cell on which the RRC release message is received.
  6. 6. A method performed by a Base Station (BS) in a wireless communication system, the method comprising: Transmitting a Radio Resource Control (RRC) release message including Multicast Broadcast Service (MBS) configuration information to a User Equipment (UE), wherein the MBS multicast configuration is associated with receiving MBS multicast in an RRC inactive state, and A message regarding an RRC connection recovery procedure is received from the UE, Wherein the RRC connection recovery procedure is performed in case there is no group radio network temporary identifier (G-RNTI) in the cell indicating to stop monitoring the multicast session to which the UE has joined.
  7. 7. The method according to claim 6, wherein the method comprises, Wherein in case a point-to-multipoint (PTM) configuration for the multicast session is not available in said cell, an RRC connection recovery procedure is performed, Wherein the PTM configuration is included in the MBS configuration information.
  8. 8. The method of claim 6, further comprising: Transmitting a paging message to the UE, the paging message including configuration information regarding reception of MBS multicast for the multicast session in the RRC inactive state, Wherein the paging message includes a Temporary Mobile Group Identity (TMGI), Wherein, the G-RNTI corresponds to the TMGI, Wherein in case that an MBS Control Channel (MCCH) for a multicast session indicated by a TMGI does not exist in the cell, an RRC connection restoration procedure is performed.
  9. 9. A User Equipment (UE) in a wireless communication system, the UE comprising: Transceiver, and A controller coupled with the transceiver and configured to: receiving a Radio Resource Control (RRC) release message including Multicast Broadcast Service (MBS) configuration information from a Base Station (BS), wherein the MBS multicast configuration is associated with receiving MBS multicast in an RRC inactive state; performing cell selection of a cell, and In case the UE is not instructed to stop monitoring a group radio network temporary identifier (G-RNTI) of the multicast session the UE has joined for the cell, performing an RRC connection recovery procedure.
  10. 10. The UE of claim 9, Wherein in case a point-to-multipoint (PTM) configuration for the multicast session is not available in said cell, an RRC connection recovery procedure is performed, Wherein the PTM configuration is included in the MBS configuration information.
  11. 11. The UE of claim 9, wherein the controller is further configured to: system information block 1 (SIB 1) is received on the cell, Where SIB1 does not schedule SIB24, an RRC connection recovery procedure is performed, Wherein SIB24 is associated with MBS reception in the cell in RRC inactive state.
  12. 12. The UE of claim 9, wherein the controller is further configured to: receiving a paging message from the BS, the paging message including configuration information regarding receipt of MBS multicast in an RRC inactive state for a multicast session, and Monitor a G-RNTI corresponding to a Temporary Mobile Group Identity (TMGI) included in the paging message, Wherein in case that an MBS Control Channel (MCCH) for a multicast session indicated by a TMGI does not exist in the cell, an RRC connection restoration procedure is performed.
  13. 13. A Base Station (BS) in a wireless communication system, the base station comprising: Transceiver, and A controller coupled with the transceiver and configured to: Transmitting a Radio Resource Control (RRC) release message including Multicast Broadcast Service (MBS) configuration information to a User Equipment (UE), wherein the MBS multicast configuration is associated with receiving MBS multicast in an RRC inactive state, and A message for an RRC connection recovery procedure is received from the UE, Wherein the RRC connection recovery procedure is performed in case there is no group radio network temporary identifier (G-RNTI) in the cell indicating to stop monitoring the multicast session to which the UE has joined.
  14. 14. The BS of claim 13, wherein the BS, Wherein in case a point-to-multipoint (PTM) configuration for the multicast session is not available in said cell, an RRC connection recovery procedure is performed, Wherein the PTM configuration is included in the MBS configuration information.
  15. 15. The BS of claim 13, wherein the controller is further configured to: Transmitting a paging message to the UE, the paging message including configuration information regarding reception of MBS multicast in an RRC inactive state for the multicast session, Wherein the paging message includes a Temporary Mobile Group Identity (TMGI), Wherein, the G-RNTI corresponds to the TMGI, Wherein in case that an MBS Control Channel (MCCH) for a multicast session indicated by a TMGI does not exist in the cell, an RRC connection restoration procedure is performed.

Description

System and method for managing state transitions of multicast UEs in a wireless communication system Technical Field The present disclosure relates to wireless networks. More particularly, the present disclosure relates to methods and systems for managing state transitions, service continuity, and Packet Data Convergence Protocol (PDCP) synchronization for multicast User Equipment (UEs) in a wireless network. Background Fifth generation (5G) mobile communication technology defines a wide frequency band, making high transmission rates and new services possible, and can be implemented not only in "below 6 gigahertz (GHz)" frequency bands such as 3.5GHz, but also in "above 6 GHz" frequency bands called mmWave including 28GHz and 39 GHz. Further, it has been considered to implement a sixth generation (6G) mobile communication technology (referred to as a super 5G system) in a terahertz (THz) frequency band (e.g., 95GHz to 3THz frequency band) in order to achieve an ultra-low delay of one of a transmission rate fifty times faster than the 5G mobile communication technology and a tenth of the 5G mobile communication technology. At the beginning of development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low-delay communication (URLLC), and large-scale machine type communication (mMTC), standardization on beamforming and large-scale Multiple Input Multiple Output (MIMO) is being performed to mitigate radio wave path loss in mmWave and increase radio wave transmission distance, support parameter sets (e.g., operating a plurality of subcarrier intervals) for dynamic operation effectively using mmWave resources and slot formats, initial access techniques for supporting multi-beam transmission and broadband, definition and operation of bandwidth parts (BWP), such as Low Density Parity Check (LDPC) codes for mass data transmission and new channel coding methods of polarization codes for highly reliable transmission of control information. Layer 2 (L2) preprocessing and network slicing for providing private networks dedicated to a particular service. Currently, in view of services to be supported by the 5G mobile communication technology, discussions about improvement and performance enhancement of the initial 5G mobile communication technology are underway, and there have been physical layer standardization regarding technologies such as vehicle-to-everything (V2X) for assisting driving determination of an autonomous vehicle based on information about the position and state of the vehicle transmitted by the vehicle, and for enhancing user convenience, new radio unlicensed (NR-U) intended to meet various regulatory-related requirements in unlicensed bands, new Radio (NR) UE power saving, non-terrestrial network (NTN) as a system operation for providing covered UE-satellite direct communication in an area where communication with a terrestrial network is unavailable, and positioning. Furthermore, air interface architecture/protocols are being standardized with respect to technologies such as industrial internet of things (IIoT) for supporting new services through interworking and convergence with other industries, integrated Access and Backhaul (IAB) for providing nodes for network service area extension by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handoffs and Dual Active Protocol Stack (DAPS) handoffs, and two-step random access (2-step Random Access Channel (RACH) for NR) for simplifying the random access procedure. System architecture/services are also being standardized with respect to 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining Network Function Virtualization (NFV) and Software Defined Network (SDN) technologies, as well as Mobile Edge Computing (MEC) for receiving services based on UE location. With commercialization of the 5G mobile communication system, a connection device that has been exponentially increased will be connected to the communication network, and thus it is expected that enhanced functions and performance of the 5G mobile communication system and integrated operation of the connection device will be necessary. For this reason, new researches related to augmented reality (XR) have been arranged to effectively support Augmented Reality (AR), virtual Reality (VR), mixed Reality (MR), etc., 5G performance improvement and complexity reduction by using Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metauniverse service support, and unmanned aerial vehicle communication. Further, such development of the 5G mobile communication system will be used not only as a basis for developing a new waveform for providing coverage in the terahertz frequency band of the 6G mobile communication technology, a multi-antenna transmission technol