PDCP Entity Handover with Dual-Connectivity
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Solution Overview
Problem
Current cellular handover processes in next-generation wireless networks experience significant mobility interruption times, leading to data loss during the transition from one cell to another, as existing methods require reestablishment of packet data convergence protocol entities and security key changes, which can cause disruptions.
Innovation Solution
The method involves performing a dual-connectivity based handover procedure without reestablishing the packet data convergence protocol entity, maintaining multiple security keys to decipher packets from both source and target base stations, and relocating PDCP entities to minimize mobility interruption by adding the target base station as a secondary node and reconfiguring it as the new master node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedure is used with PDCP entity reestablishment, then security key changes are performed, but mobility interruption time increases and data loss occurs
Solution Approach 1:
The target base station performs preliminary actions by pre-establishing the PDCP entity and pre-configuring security keys before the actual handover execution. This allows the PDCP entity to be ready for immediate operation without interruption, and the UE can switch security keys seamlessly during the handover process, eliminating data loss and minimizing mobility interruption time.
Solution Approach 2:
The patent applies parameter changes by dynamically switching security keys during the handover process. The PDCP entity maintains multiple security keys and transitions from the source base station's key to the target base station's key without disrupting data flow. This key parameter change enables continuous encrypted communication while maintaining data continuity and reducing mobility interruption.
2Reliability
If PDCP entity is reestablished during handover, then security is maintained, but data exchange is interrupted and mobility interruption increases
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the PDCP entity across both source and target base stations without reestablishment. The PDCP entity continues processing data packets seamlessly during the handover, and the UE can receive and process data from both cells simultaneously. This eliminates data exchange interruption while maintaining security through key management.
Solution Approach 2:
The PDCP entity acts as an intermediary that bridges the source and target base stations during handover. By maintaining the PDCP entity and using it to process packets from both source and target cells, the system enables smooth transition without data loss. The intermediary PDCP entity manages security keys and data flow continuity, ensuring both security and productivity during the handover process.
3Loss of time
If dual-connectivity based handover is performed without PDCP reestablishment, then mobility interruption is minimized, but complex security key management is required
Solution Approach 1:
The PDCP entity is designed with multi-functionality to handle security key management for both source and target base stations. It universally processes packets from either cell using the appropriate security key, eliminating the need for separate PDCP entities. This multi-functional approach minimizes mobility interruption time while managing security complexity through a single versatile entity that handles multiple functions.
Data Source
AI summary
Some of the present implementations provide a method for a user equipment (UE) for performing a handover procedure with minimum mobility interruption. The method receives, at the UE, a reconfiguration message that has an indicator for performing a dual-connectivity based (DC-based) handover procedure. The method then performs the DC-based handover procedure without reestablishing a packet data convergence protocol (PDCP) entity of the UE during the DC-based handover procedure. The PDCP entity maintains a plurality of security keys to decipher PDCP packets received from at least one of a source base station and a target base station during the handover procedure and while the UE is transitioning from the source base station to the target base station.