RLC Entity Redirection for Inter-Base Station Carrier Aggregation
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Solution Overview
Problem
In inter-base station carrier aggregation scenarios, when data sent by a UE using RLC of a secondary base station reaches a maximum quantity of retransmissions, a radio link failure is detected, leading to RRC connection re-establishment and subsequent data packet loss, negatively impacting user experience.
Innovation Solution
A method where the first RLC entity of a terminal instructs the second RLC entity, corresponding to a different base station, to retransmit the packet data unit upon reaching the maximum quantity of retransmissions, thereby avoiding RRC connection re-establishment and reducing data packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE initiates RRC connection re-establishment when RLC retransmission reaches maximum quantity, then radio link failure is detected and connection is re-established, but data packet loss occurs and user experience deteriorates
Solution Approach 1:
The patent introduces an intermediary mechanism where the first RLC entity acts as a mediator to redirect retransmission requests to the second RLC entity. When the first RLC entity detects maximum retransmissions, it sends a retransmission indication to the PDCP entity, which then forwards the data to the second RLC entity for retransmission, avoiding direct RRC re-establishment and preventing packet loss.
Solution Approach 2:
The patent segments the retransmission function across two separate RLC entities corresponding to different base stations. Instead of having a single RLC entity handle all retransmissions (which would trigger RRC re-establishment), the system divides the retransmission load between first and second RLC entities, allowing seamless failover without connection re-establishment.
2Reliability
If RRC connection re-establishment is performed frequently to handle retransmission failures, then connection reliability is maintained, but transmission interruption increases and user experience worsens
Solution Approach 1:
The patent implements preliminary action by pre-configuring multiple RLC entities and establishing backup retransmission paths before failures occur. When the first RLC entity detects maximum retransmissions, the switch to the second RLC entity can occur immediately without needing to initiate RRC re-establishment, thus preventing transmission interruptions.
3Device complexity
If a single RLC entity handles all retransmissions, then system complexity is low, but the frequency of RRC re-establishment increases and packet loss occurs
Solution Approach 1:
The patent applies universality by making the PDCP entity multi-functional - it not only performs its standard packet convergence functions but also acts as a coordinator that receives retransmission indications from the first RLC entity and forwards data to the second RLC entity. This multi-functionality enables the system to handle retransmissions across multiple base stations without significantly increasing overall system complexity.
Data Source
AI summary
Embodiments of the present disclosure disclose a data retransmission communication method and a terminal for implementing inter-base station carrier aggregation, where the method includes: receiving, by a first Radio Link Control (RLC) entity of a terminal, a packet data unit PDU; and when the first RLC entity determines that the PDU reaches a maximum quantity of retransmissions, instructing, by the first RLC entity, a second RLC entity of the terminal to transmit the PDU, where the first RLC entity is corresponding to a first base station, and the second RLC entity is corresponding to a second base station. By using the method and the terminal in the embodiments, frequency of RRC connection re-establishment is reduced, and a data packet loss caused by frequent re-establishment is further avoided, thereby improving user experience.