PDCP Version Handling in EN-DC Handovers
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Solution Overview
Problem
Current wireless communication systems, particularly in the transition from LTE to NR, face challenges in handling PDCP version changes and bearer reconfigurations during handovers, leading to potential data loss and complexity in managing different PDCP state variables and security keys across LTE and NR networks.
Innovation Solution
A method and system for E-UTRA-NR Dual Connectivity (EN-DC) capable User Equipment (UE) that manages PDCP operation by processing handover messages, re-establishing PDCP entities, and translating state variables between LTE and NR formats, ensuring lossless transition and bearer reconfiguration through modified PDCP re-establishment procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PDCP version changes are implemented during handover from LTE to NR, then network adaptability and service continuity are improved, but system complexity increases due to managing different PDCP state variables and security keys
Solution Approach 1:
The patent applies parameter changes by dynamically switching between LTE PDCP and NR PDCP formats based on the handover state. The system changes parameters such as sequence number formats, header structures, and security key configurations to match the target network version, enabling seamless transition while managing complexity through standardized parameter transformation rules
Solution Approach 2:
The patent introduces an intermediary translation mechanism that converts PDCP state variables between LTE and NR formats. This intermediary layer handles the complexity of state variable mapping and security key translation, shielding the upper layers from version-specific details while enabling smooth handover transitions
2Reliability
If PDCP re-establishment procedures are modified to support version changes, then data transmission reliability is improved, but processing time and operational complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring PDCP state variables and security keys during the handover preparation phase. The target base station pre-computes the necessary PDCP parameters and security context, allowing the UE to quickly switch versions without extensive real-time processing, thus maintaining reliability while reducing handover time
Solution Approach 2:
The patent ensures continuity of useful action by maintaining PDCP data flow during the version transition. The system continues processing and forwarding PDCP packets through the re-establishment procedure, using buffer mechanisms and sequence number continuity to prevent data loss and minimize interruption time
Data Source
AI summary
Embodiments herein disclose a method for handling PDCP operation by an EN-DC capable UE in a wireless communication system. The method includes receiving, by an EN-DC capable UE, LTE PDCP PDUs from the LTE RLC entity by a receiver LTE PDCP entity upon re-establishing LTE RLC entity based on the indication that indicates a PDCP version change from a LTE PDCP to a NR PDCP. Further, the method includes processing the LTE PDCP PDUs at the receiver LTE PDCP entity using a LTE format. Further, the method includes reestablishing the receiver LTE PDCP entity and a transmitter LTE PDCP entity of the UE.