Multicast PTM Configuration Across RRC Connected and Inactive States
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Solution Overview
Problem
Existing 3GPP specifications allow multicast reception only for user equipment in a radio resource control (RRC) connected state, limiting the flexibility and efficiency of multicast services in 5G/NR networks.
Innovation Solution
A communication method enabling user equipment in an RRC inactive state to receive multicast services by providing a PTM configuration on a dedicated control channel (DCCH) during the RRC connected state, allowing seamless transition to RRC inactive state while maintaining multicast reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multicast reception is limited to RRC connected state only, then control and management of multicast sessions is simplified, but service continuity and user flexibility are reduced when devices transition to inactive state
Solution Approach 1:
The patent applies preliminary action by providing PTM configuration information to the UE in advance while in RRC connected state, before the UE transitions to inactive state. This pre-provisioning of configuration data (including SC-PTM parameters, resource allocation, and session information) enables the UE to maintain multicast reception capability in inactive state without requiring complex real-time configuration management during state transition.
2Ease of operation
If PTM configuration is provided on DCCH for inactive state devices, then multicast reception flexibility is improved, but signaling overhead and configuration complexity increases
Solution Approach 1:
The patent merges the PTM configuration information delivery into the existing DCCH signaling framework used for RRC connected state management. By combining multicast configuration delivery with the existing dedicated control channel infrastructure, the patent avoids creating separate signaling mechanisms, thereby reducing overall signaling overhead while enabling seamless state transition for multicast reception.
Solution Approach 2:
The DCCH channel is made multi-functional by using it both for traditional RRC connected state control and for providing PTM configuration information for inactive state multicast reception. This universal usage of the existing DCCH infrastructure eliminates the need for additional dedicated signaling channels, reducing system complexity and signaling overhead.
3Reliability
If multicast session configuration is provided in advance before activation, then service continuity is improved during state transitions, but configuration management complexity increases
Solution Approach 1:
The patent implements preliminary action by providing complete PTM configuration information to the UE in advance, before the multicast session is activated and before the UE transitions to inactive state. This pre-provisioning ensures that when the UE enters inactive state, it already possesses all necessary configuration parameters to maintain uninterrupted multicast reception, thereby improving reliability without requiring complex real-time configuration management.
Data Source
AI summary
A communication method used in a mobile communication system for providing a multicast/broadcast service (MBS) includes receiving, by a user equipment in a radio resource control (RRC) connected state and having joined a multicast session, a point-to-multipoint (PTM) configuration for the multicast session on a dedicated control channel (DCCH) from a base station. The receiving includes receiving, on the DCCH from the base station, the PTM configuration including an information element that is the same as an information element provided on a multicast control channel (MCCH) when the multicast session is activated.