PDCP Entity Header Compression for Handover Robustness
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Solution Overview
Problem
Current LTE and NR technologies face challenges in efficiently controlling mobility during handover processes, particularly in minimizing user data interruption and improving handover robustness, with a lack of detailed operations for terminal apparatus mobility control.
Innovation Solution
A terminal apparatus is configured with a PDCP entity that includes specific ciphering and integrity protection algorithms linked to RLC entities, enabling efficient header compression and key management for unidirectional mode operations during handover, facilitating efficient mobility processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LTE and NR handover mechanisms are used, then basic mobility support is provided, but user data interruption occurs during handover and handover robustness is insufficient
Solution Approach 1:
The patent applies preliminary action by establishing a second RLC entity and configuring header compression in advance before actual handover occurs. The terminal apparatus pre-configures the second RLC entity with header compression enabled, so that when handover is needed, the data path can be switched without interruption. This advance preparation eliminates the need for data retransmission during handover, directly reducing user data interruption time while improving handover robustness.
2Productivity
If header compression is enabled in both RLC entities, then data transmission efficiency is improved, but device complexity increases due to dual RLC entity configuration
Solution Approach 1:
The patent applies segmentation by dividing the RLC entity into two separate entities (first RLC entity and second RLC entity), each handling different data paths. The first RLC entity processes data for the current connection while the second RLC entity prepares data for the upcoming connection. This segmentation allows independent optimization of each entity's header compression operations, improving overall data transmission efficiency while managing complexity through clear functional separation.
Solution Approach 2:
The patent applies dynamics by making the RLC entity configuration changeable and adaptable. The terminal apparatus can dynamically switch between the first and second RLC entities based on handover status. When handover is detected, the system dynamically activates the second RLC entity with header compression enabled, while deactivating the first. This dynamic reconfiguration allows the system to optimize data transmission efficiency only when needed, managing device complexity through conditional activation rather than permanent dual-entity operation.
Data Source
AI summary
Provided is a terminal apparatus, wherein based on detection of a request, for a PDCP SDU received from an upper layer, the terminal apparatus performs header compression of the PDCP SDU by using second header compression processing, performing ciphering by using a second ciphering algorithm, a second ciphering key, and a COUNT value, performs integrity protection of the PDCP SDU by using a second integrity protection algorithm, a second integrity protection key, and the COUNT value, and submits a PDCP PDU created, to the second RLC entity.