PDCP Status Report Trigger for 5G MBS Bearer Changes
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Solution Overview
Problem
Current 5G/NR multicast and broadcast services face challenges in providing enhanced services compared to 4G/LTE, particularly in managing packet loss during bearer type changes in mobile communication systems, which affects data reception reliability and efficiency.
Innovation Solution
The implementation of a communication method in user equipment and base stations that autonomously triggers a PDCP status report upon specific bearer type changes, enabling compensation for packet loss by retransmitting missing packets and maintaining header compression protocols, thereby ensuring reliable data reception and efficient resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bearer type change is implemented in MRB, then service flexibility and adaptability are improved, but packet loss occurs and data reception reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by triggering a PDCP status report transmission before or during the bearer type change process. When the RRC reconfiguration message indicates a change to AM MRB type, the UE proactively sends a PDCP status report to notify the base station of the reception status, enabling the base station to retransmit any missing packets before the bearer change completes, thus preventing packet loss.
Solution Approach 2:
The patent implements feedback by establishing a status report mechanism where the UE continuously informs the base station about its data reception status through PDCP status reports. This feedback loop allows the base station to identify and retransmit missing packets, ensuring reliable data delivery even during bearer type transitions.
2Reliability
If PDCP status report transmission is triggered autonomously, then packet loss compensation is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent applies local quality by making the PDCP status report transmission specific to certain conditions rather than universally applicable. The autonomous triggering is specifically applied when transitioning from idle/inactive state to connected state, or when discard occurs in the RLC layer, rather than for all possible events. This targeted approach provides packet loss compensation where needed while avoiding unnecessary signaling overhead in other scenarios.
3Productivity
If header compression protocol state is maintained during bearer type change, then data transmission efficiency is improved, but risk of state inconsistency and packet loss increases
Solution Approach 1:
The patent implements continuity of useful action by maintaining the header compression protocol state during bearer type change. The RRC reconfiguration message includes a second information element that explicitly指示es the PDCP entity to maintain the header compression state, allowing efficient data transmission to continue uninterrupted while the bearer type transitions, thus preserving both efficiency and consistency.
Data Source
AI summary
In a first aspect, a communication method is a communication method performed by a user equipment in a mobile communication system that provides a multicast and broadcast service (MBS) and includes receiving MBS data from a base station via a multicast radio bearer (MRB), receiving, from the base station, a radio resource control (RRC) reconfiguration message indicating a bearer type change of the MRB, triggering transmission of a PDCP status report indicating a data reception status in a PDCP entity associated with the MRB in response to the bearer type change indicated by the RRC reconfiguration message being a change to an Acknowledged Mode (AM) MRB type, and transmitting the PDCP status report to the base station.