Dual Active Protocol Stack Handover for Wireless Communication
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Solution Overview
Problem
Next-generation mobile communication systems face challenges in maintaining uninterrupted data transmission during handover processes, leading to potential data interruptions and delays.
Innovation Solution
The implementation of a dual active protocol stack (DAPS) method, where user equipment (UE) configures protocol layers for both source and target base stations, allowing continuous data transmission and reception without interruption by switching uplink data transmission to the target base station during the handover process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover method is used, then device complexity is reduced, but data transmission interruption occurs during handover
Solution Approach 1:
The UE configures protocol layers for both source and target base stations before actually switching data transmission. This preliminary configuration of dual protocol stacks ensures that when handover occurs, the target base station's protocol layers are already ready, eliminating data transmission interruptions while managing complexity through structured pre-configuration
Solution Approach 2:
The patent maintains continuous data transmission by keeping both source and target base station protocol stacks active simultaneously during handover. The UE continues to transmit and receive data through the source base station while parallel protocol layers for the target base station are configured and prepared, ensuring uninterrupted service
2Loss of time
If dual active protocol stack is configured, then data transmission continuity is improved, but device complexity increases
Solution Approach 1:
The patent segments the protocol stack into multiple independent layers (PDCP, RLC, MAC, PHY) that can be configured and managed separately for source and target base stations. This segmentation allows the UE to handle dual active protocol stacks more efficiently by managing each layer independently, reducing the perceived complexity while maintaining continuous data transmission
Solution Approach 2:
The UE configures protocol layers for both source and target base stations, which is more than the traditional single-stack approach. This excessive configuration of dual stacks ensures zero interruption time by having redundant protocol paths ready, accepting the temporary complexity increase as necessary to eliminate handover gaps
3Reliability
If data transmission continues through source base station during handover, then service continuity is maintained, but handover efficiency is reduced
Solution Approach 1:
The UE performs preliminary configuration of target base station protocol layers before switching data transmission paths. This pre-configuration includes setting up PDCP, RLC, MAC, and PHY layers for the target base station while maintaining active data transmission through the source base station, enabling seamless switching without reconfiguration delays
Data Source
AI summary
Provided is a method performed by a user equipment (UE) in a wireless communication system. The method includes: receiving, from a source base station, a first radio resource control (RRC) reconfiguration message including configuration information indicating reconfiguration with sync, identification information of a bearer, and dual active protocol stack (DAPS) configuration information indicating that the bearer is configured as a DAPS bearer; reconfiguring a packet data convergence protocol (PDCP) entity of the UE with respect to the bearer; switching uplink data transmission from the source base station to a target base station; and releasing the source base station.