MBMS Service Context Handling for Paging Idle Connected UEs
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Solution Overview
Problem
In Multimedia Broadcast/Multicast Services (MBMS), UEs in PMM-Idle/RRC-Connected mode may fail to receive MBMS paging due to lack of information in the MBMS service context, especially when the PS network does not recognize the RRC connection for CS services, leading to incomplete MBMS service delivery.
Innovation Solution
The method involves transmitting MBMS service-related information from UEs to RNCs and SGSNs, linking this information with UE data, and storing it in MBMS service contexts to ensure that UEs in all states, including PMM-Idle/RRC-Connected mode, can receive MBMS paging by managing MBMS service contexts in RNCs and SGSNs effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If MBMS service context is managed only in SGSN without RNC, then network complexity is reduced, but UEs in PMM-Idle/RRC-Connected mode cannot receive MBMS paging
Solution Approach 1:
The patent segments the MBMS service context management between two network entities: SGSN stores MBMS service context information (TMGI, service area, etc.) while RNC stores UE-specific MBMS reception status. This segmentation allows each node to maintain necessary information for its specific function, enabling reliable paging of UEs in different states without requiring one node to store all possible information.
Solution Approach 2:
The patent introduces an intermediary mechanism where the RNC acts as a mediator between the SGSN and UEs in PMM-Idle/RRC-Connected mode. The RNC receives MBMS service context from SGSN, maintains UE-specific reception status, and uses this information to determine whether to page UEs for MBMS service announcements, thus bridging the gap between centralized context management and distributed UE state management.
2Reliability
If MBMS service context information is stored in both SGSN and RNC, then MBMS paging reliability for all UE states is improved, but information storage and synchronization complexity increases
Solution Approach 1:
The patent applies local quality by defining different information storage requirements for different network nodes based on their specific functions. SGSN stores general MBMS service context (TMGI, service area, scheduling information) while RNC stores UE-specific MBMS reception status. This localized information storage ensures each node has exactly the information it needs for its function, avoiding redundant storage and synchronization overhead.
Solution Approach 2:
The patent implements preliminary action by having the SGSN pre-send MBMS service context information to relevant RNCs before UE paging is needed. The RNC then maintains UE-specific reception status in advance, so when MBMS service announcements need to be paged, the RNC already has the necessary information to determine which UEs to page and how to page them appropriately.
3Adaptability or versatility
If RNC manages MBMS service context for PMM-Idle UEs, then MBMS service delivery to all UE states is achieved, but RNC processing load and memory usage increase
Solution Approach 1:
The patent applies partial action by having the RNC manage only UE-specific MBMS reception status information rather than complete MBMS service context. The RNC maintains a simplified data structure containing only the TMGI and reception status for each UE, while relying on the SGSN for comprehensive service context. This partial management approach enables support for UEs in all states without requiring the RNC to process and store excessive information.
Data Source
AI summary
A method for managing information on user equipments (UEs) in a mobile communication system supporting an MBMS (Multimedia Broadcast/Multicast Service) service. A radio network controller (RNC) provides a packet switched (PS) service and a circuit switched (CS) service to the UEs. A UE that is in a Packet Mobility Management-Idle (PMM-Idle) mode after joining at least one MBMS service, transmits MBMS service-related information thereof to the RNC, and the RNC stores the MBMS service-related information in a first service context for the MBMS service held in the RNC, together with information on the UE.