PDCP Path Switching for Preprocessed Data Transfer
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Solution Overview
Problem
In LTE communication systems, the high instantaneous processing capability required for data transmission leads to poor path switching performance when a terminal device switches from one cell group to another, as preprocessed data are not effectively switched, resulting in decreased switching efficiency.
Innovation Solution
A path switching method where the terminal device sends uplink data from the PDCP layer to the RLC layer of the first cell group and then switches to the second cell group, allowing for the transmission of preprocessed data to improve switching performance by sending data that have been sent to the RLC layer but not correctly received or mapped to a MAC PDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the UE performs data preprocessing from PDCP layer to RLC layer before uplink resource grant arrives, then the instantaneous processing capability requirement is reduced, but the path switching performance deteriorates due to inability to switch preprocessed data
Solution Approach 1:
The patent extracts the preprocessed data from the first cell group's RLC layer and transfers it to the second cell group's RLC layer during path switching. This allows the preprocessed data to be reused in the new cell group, resolving the contradiction by maintaining both reduced processing requirements and improved switching performance.
Solution Approach 2:
The patent performs preliminary data preprocessing from PDCP to RLC layer in advance, storing the preprocessed data in a switchable buffer. When path switching occurs, the preprocessed data is already prepared and can be quickly transferred to the new cell group, maintaining both the benefit of reduced instantaneous processing and the ability to switch efficiently.
2Speed
If the UE switches PDCP layer data sending from first cell group to second cell group, then the path switching speed is improved, but data transmission reliability may worsen due to potential data loss or duplication
Solution Approach 1:
The patent implements feedback mechanisms where the RLC layer monitors data transmission status and provides feedback information about successfully transmitted and duplicate data. This feedback system ensures that during path switching, data is not lost or duplicated, maintaining transmission reliability while enabling fast switching.
Solution Approach 2:
The patent introduces the RLC layer as an intermediary between the PDCP layer and the cell groups. The RLC layer buffers and manages the data during switching, acting as a mediator that ensures data integrity is maintained while the PDCP layer可以快速 switch between cell groups.
Data Source
AI summary
Provided are a path switching method and a terminal device. The terminal device has a packet data convergence protocol (PDCP) layer, the PDCP layer being able to send uplink data to a first cell group or a second cell group, the first cell group and the second cell group being different cell groups, the PDCP layer currently sending the uplink data to the first cell group; the method comprises: the terminal device enabling the switching of the PDCP layer from sending the uplink data to the first cell group, to sending the uplink data to the second cell group; and the terminal device sending first uplink data to the second cell group, the first uplink data at least including first data, the first data referring to the data that the terminal device has sent to a radio link control protocol (RLC) layer of the first cell group.