DAPS Handover Protocol Stack Setup for Zero-Interruption Data Transfer

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Solution Overview

Problem

Existing mobile communication systems face challenges in performing handover without data transmission interruption, particularly in next-generation systems like 5G, which require efficient methods to minimize latency and maintain service continuity during handover.

Innovation Solution

The proposed solution involves configuring dual active protocol stacks (DAPS) at the user equipment (UE) to maintain simultaneous data transmission with both the source and target base stations during the handover process, utilizing dual bearers for seamless data transfer without interruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional handover method is used, then handover process is simple, but data transmission interruption occurs during handover

Engineering Contradiction:

Improveservice continuityVSAvoiddata interruption time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The UE configures and activates dual protocol stacks (source and target) before completing the handover process. This preliminary configuration of the target protocol stack enables seamless switching and eliminates data interruption during handover, as the target stack is already ready to handle data transmission immediately upon activation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dual active protocol stack architecture maintains continuous data transmission capability by keeping both source and target protocol stacks active simultaneously. The UE can switch between stacks without interruption, ensuring continuous useful action in data transmission throughout the handover process.

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If dual active protocol stack is configured, then data transmission continuity is maintained, but device complexity increases

Engineering Contradiction:

Improveservice continuityVSAvoidprotocol stack configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protocol architecture is segmented into distinct source and target protocol stacks, each handling specific data transmission tasks. This segmentation allows independent management and activation of each stack, reducing the complexity burden by organizing the dual-stack system into modular, independently controllable units.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protocol stack configuration is made dynamic, allowing the UE to activate or deactivate source and target stacks as needed during handover. This dynamic activation reduces complexity by only maintaining active the necessary stacks at any given time, rather than permanently running all stacks simultaneously.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4221333B1Method and apparatus for performing DAPS handover in wireless communication system

Publication Date: 2026.03.04 SAMSUNG ELECTRONICS CO LTD

Figure 1A~1B
Figure 1C~1D
Figure 1E

AI summary

A method of performing dual active protocol stack (DAPS) handover by a user equipment (UE) in a wireless communication system includes: receiving, from a source base station, a radio resource control (RRC) reconfiguration message including DAPS configuration information indicating at least one bearer for a DAPS handover; reconfiguring, for the DAPS handover, a packet data convergence protocol (PDCP) entity corresponding to the at least one bearer for the DAPS handover; and establishing protocol entities for a target cell corresponding to the at least one bearer for the DAPS handover.