MBS Data Reception Reliability via Dynamic RNTI Switching
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Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in efficiently managing Multicast-Broadcast Service (MBS) data reception, including handling unsuccessful receptions and optimizing data recovery processes.
Innovation Solution
A method and user equipment (UE) solution that involves receiving a Discontinuous Reception (DRX) configuration mapped to an MBS, monitoring a Physical Downlink Control Channel (PDCCH) associated with a Group Radio Network Temporary Identifier (G-RNTI), and using a Cell Radio Network Temporary Identifier (C-RNTI) to decode a second Downlink (DL) assignment while a timer is running, enabling retransmission of MBS data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE uses G-RNTI to monitor PDCCH for MBS data reception, then the UE can efficiently receive multicast/broadcast data, but the UE cannot simultaneously receive unicast retransmissions using C-RNTI during the DRX active time
Solution Approach 1:
The patent implements dynamic switching between G-RNTI and C-RNTI monitoring modes based on reception status. When PDSCH decoding succeeds, the UE continues using G-RNTI for MBS data. When decoding fails and the timer expires, the UE dynamically switches to C-RNTI to monitor for unicast retransmissions, providing adaptability while maintaining initial efficiency
Solution Approach 2:
The patent segments the reception process into distinct phases: initial MBS data reception using G-RNTI, failure detection, timer-based waiting period, and fallback to C-RNTI for retransmissions. This segmentation allows the system to maintain efficient group communication while providing individual recovery paths when needed
2Reliability
If the UE monitors PDCCH continuously for retransmissions, then the UE can ensure reliable data recovery, but the UE consumes excessive power and reduces battery life
Solution Approach 1:
The patent implements periodic monitoring through a timer mechanism. After unsuccessful PDSCH reception, the UE starts a timer and monitors PDCCH only during the timer duration for potential retransmissions. This periodic approach ensures reliable data recovery within a defined window while avoiding continuous monitoring that would drain battery power
Solution Approach 2:
The patent performs preliminary action by starting the timer immediately after PDSCH decoding failure. This pre-configures the monitoring window in advance, allowing the UE to know exactly when to wake up and monitor for retransmissions, rather than continuously monitoring or waiting passively
3Adaptability or versatility
If the UE uses C-RNTI to decode DL assignments during timer operation, then the UE can receive unicast retransmissions, but the system complexity increases due to dual RNTI management
Solution Approach 1:
The patent implements self-service through automatic RNTI switching based on reception status and timer state. The UE autonomously determines when to switch from G-RNTI to C-RNTI monitoring without complex external control, reducing system complexity while maintaining dual-mode capability. The switching logic is embedded in the UE's DRX configuration and HARQ process management
Data Source
AI summary
A method performed by a UE for management of MBS data reception is provided. The method includes receiving a DRX configuration mapped to an MBS, the DRX configuration including a timer and controlling activity of the UE for monitoring a PDCCH associated with a G-RNTI of the MBS; receiving a first DL assignment associated with the G-RNTI on the PDCCH; identifying an unsuccessful reception of a PDSCH that is scheduled by the first DL assignment and used for receiving data of the MBS; starting the timer after identifying the unsuccessful reception of the PDSCH; and enabling use of a C-RNTI to decode a second DL assignment while the timer is running. A UE using the method is also provided.