Terminal PDCP Entity Configuration 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 designed to receive RRC reconfiguration messages from a base station, establishing and configuring PDCP entities with specific ciphering and integrity protection algorithms and keys, enabling efficient mobility processing by applying these configurations based on upper-layer requests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal apparatus applies multiple ciphering algorithms and keys during handover, then handover robustness is improved, but device complexity increases
Solution Approach 1:
The terminal apparatus applies the first ciphering algorithm and first integrity protection algorithm before handover is completed, preparing security configurations in advance. This preliminary action ensures that security context is already established at the target base station, improving handover robustness without requiring complex real-time switching during the handover execution phase.
Solution Approach 2:
The patent divides the security configuration into separate, manageable components: first ciphering algorithm, first integrity protection algorithm, second ciphering algorithm, and second integrity protection algorithm. Each algorithm and key pair is independently configured and applied based on specific handover conditions, allowing the system to handle multiple security contexts without overwhelming complexity.
2Reliability
If simultaneous presence of two protocol stacks is implemented, then user data interruption is reduced, but device complexity increases
Solution Approach 1:
The terminal apparatus establishes the first PDCP entity with the first ciphering algorithm and first integrity protection algorithm before handover, while maintaining the existing second PDCP entity. This preliminary setup of dual protocol stacks allows seamless switching during handover, ensuring user data continuity without requiring complex real-time protocol transformations.
Solution Approach 2:
The patent introduces PDCP entities as intermediary layers between the upper layers and lower protocol layers. By configuring multiple PDCP entities with different security algorithms, the system can mediate between source and target base stations, allowing smooth transition of user data without direct exposure of lower layer complexities during handover.
Data Source
AI summary
A terminal apparatus for communicating with a base station apparatus, the terminal apparatus including: a receiver configured to receive an RRC reconfiguration message from the base station apparatus; and a processing unit, wherein the processing unit establishes a PDCP entity in accordance with the RRC reconfiguration message, applies, to the PDCP entity, a first ciphering algorithm, a first ciphering key, a first integrity protection algorithm, and a first integrity protection key provided by an upper layer, and based on a first request made by the upper layer, applies, to the PDCP entity, a second ciphering algorithm, a second ciphering key, a second integrity protection algorithm, and a second integrity protection key provided by the upper layer.