Terminal PDCP Entity Management for Handover Latency Reduction
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Solution Overview
Problem
The handover process in communications systems experiences latency due to sequence number status transfer and data packet forwarding between source and target base stations, especially when backhaul between base stations is unsatisfactory, leading to reduced user experience for latency-sensitive services.
Innovation Solution
A communication method that involves maintaining a first connection with the source network device while establishing a second connection with the target network device, without performing sequence number status transfer and data packet forwarding, allowing the terminal to manage connections and detect duplicate packets, thereby reducing latency and improving transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequence number status transfer and data packet forwarding are performed between source and target base stations during handover, then data transmission continuity is maintained, but handover latency increases significantly
Solution Approach 1:
The terminal performs PDCP entity reestablishment and receives handover configuration information in advance during the handover preparation phase, before actual data transmission needs to switch networks. This allows the terminal to be ready for immediate data transmission on the target network without waiting for post-handover setup, thereby reducing handover latency while maintaining data continuity through proactive configuration.
2Stability of the object's composition
If sequence number status transfer is performed between base stations, then data packet ordering is ensured, but backhaul latency increases when backhaul conditions are unsatisfactory
Solution Approach 1:
The terminal autonomously manages PDCP entity reestablishment and generates PDCP status reports without requiring sequence number status transfer messages from the source base station. This self-service approach eliminates the backhaul dependency for status transfer, allowing the terminal to independently ensure data packet ordering and continuity even when backhaul conditions are poor, thereby reducing backhaul latency.
3Reliability
If data packet forwarding is performed from source to target base station, then data transmission is maintained during handover, but additional signaling and processing time are required
Solution Approach 1:
The patent extracts the data forwarding function from the network side (base stations) and transfers it to the terminal side. The terminal directly receives data from the target base station after handover without requiring the source base station to forward data packets through the backhaul. This extraction eliminates the complex signaling and processing required for inter-base-station data forwarding while maintaining data transmission reliability.
Data Source
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AI summary
Embodiments of this application disclose a communication method and a communications apparatus. A source base station indicates a terminal to hand over from the source base station to a target base station, and sends, to the terminal, configuration information of a second connection required for communication between the terminal and the target base station. The terminal maintains a first connection for communication with the source base station, and establishes the second connection for communication with the target base station based on the configuration information of the second connection. A packet data convergence protocol PDCP entity corresponding to the second connection and a PDCP entity corresponding to the first connection are a same PDCP entity or different PDCP entities. The solutions in the embodiments of this application can reduce a latency in a handover process.