5G MBS Handover Continuity With Assistance Information
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Solution Overview
Problem
Existing wireless systems face limitations in providing seamless multicast-broadcast services (MBS) due to issues such as service continuity gaps, inefficient UE interest indication, and inflexible control information acquisition, particularly in LTE and UTRAN MBMS operations, which are not optimized for 5G NR requirements.
Innovation Solution
Implementing MBS assistance information, modified measurement and cell reselection rules, and enhanced handover procedures to ensure service continuity and dynamic switching between PTM and PTP transmission modes, along with UE assistance for MBS service continuity in 5G NR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic transmission areas are implemented in 5G NR MBS, then transmission flexibility and adaptability are improved, but service continuity and transmission stability deteriorate due to coverage holes and synchronization issues
Solution Approach 1:
The patent applies preliminary action by introducing MBS assistance information that is provided to UEs before handover occurs. This assistance information includes scheduling information defining MBS reception windows and cell reselection parameters, enabling UEs to prepare for and anticipate MBS transmission continuity during dynamic transmission area changes, thereby maintaining service continuity while allowing transmission flexibility.
Solution Approach 2:
The patent implements feedback mechanisms where UEs send UE assistance information back to the network, and the network provides MBS assistance information to UEs. This bidirectional feedback loop enables continuous optimization of transmission parameters and synchronization during dynamic transmission area operations, resolving the contradiction between flexibility and continuity.
2Adaptability or versatility
If modified measurement rules are applied to allow MBS coverage holes, then cell reselection capability is improved, but measurement accuracy and synchronization precision deteriorate
Solution Approach 1:
The patent applies local quality by introducing cell reselection offsets specific to MBS services, treating MBS cell reselection differently from conventional cell reselection. The offset parameter allows UEs to prioritize cells with MBS coverage even if they have slightly lower signal quality, enabling adaptation to MBS coverage holes while maintaining acceptable measurement precision through localized parameter adjustment.
3Reliability
If modified handover procedures are implemented for lossless MBS transmission, then service continuity is improved, but handover complexity and procedure overhead increase
Solution Approach 1:
The patent applies preliminary action by providing MBS assistance information to UEs before handover occurs, including scheduling information and reception window definitions. This pre-provisioning enables UEs to maintain MBS reception continuity during handover without requiring complex real-time coordination, thereby improving service continuity while limiting the increase in handover complexity to manageable levels.
4Adaptability or versatility
If UE assistance information is used for dynamic switching between PTM and PTP, then transmission adaptability is improved, but UE processing complexity and information management overhead increase
Solution Approach 1:
The patent applies dynamics by enabling dynamic switching between PTM and PTP transmission modes based on UE assistance information and network conditions. The system transitions from static transmission mode assignment to dynamic mode selection, allowing the network to optimize transmission based on real-time UE capabilities and service requirements while managing UE processing complexity through standardized information exchange protocols.
Data Source
AI summary
Wireless User Equipment, UE, and network apparatuses may be adapted to facilitate continuity of Multicast/Broadcast Service, MBS, across cells. A UE in idle/inactive mode, for example, may receive MBS assistance information comprising scheduling information defining MB S reception windows and perform a cell re selection evaluation process accordingly. An UE in connected mode may conduct and report MB S quality measurements and receive an RRC reconfiguration comprising an MB S configuration for a target cell, determine that MBS transmission progress differs between the source cell and the target cell, and recover lost MBS PDUs or delete duplicate MBS PDUs accordingly. A network apparatus, such as a gNB for example, may map a GPRS Tunneling Protocol Sequence Number of an MBS PDU, to a Packet Data Convergence Protocol Sequence Number in a target cell, and determine an MB S configuration for use by a UE requesting a handover accordingly.