Dual-Connectivity Handover With Parallel Random Access

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Solution Overview

Problem

In wireless communication systems, performing handovers in dual connectivity scenarios often results in increased time duration due to the sequential execution of random access procedures with target nodes, leading to throughput degradation and potential data inefficiencies such as retransmissions or duplicates.

Innovation Solution

User equipment initiates parallel random access procedures with target master and secondary nodes, allowing data transfer with the secondary node before completing the random access with the master node, and implements mechanisms to avoid redundant data transmissions upon failure of the master node procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sequential random access procedures are performed with target master node and secondary node, then reliability of handover is improved, but handover time duration increases

Engineering Contradiction:
Improvehandover reliabilityVSAvoidhandover time duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The UE performs the random access procedure with the target secondary node in advance before completing the random access procedure with the target master node. This preliminary action allows data transfer to start earlier on the secondary node path, reducing overall handover time while maintaining reliability through coordinated failure handling between the two procedures

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If parallel random access procedures are performed with target master node and secondary node, then handover time is reduced, but complexity of procedure coordination increases

Engineering Contradiction:
Improvehandover time durationVSAvoidprocedure coordination complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system implements feedback mechanisms where the UE monitors the outcome of the random access procedure with the target master node and provides this information to coordinate with the secondary node procedure. This feedback loop enables automatic failure handling and data transfer coordination, reducing the perceived complexity while maintaining parallel execution benefits

Inventive Principle:
Principle #23Feedback

3Reliability

If data transfer is delayed until master node random access completes, then data transmission reliability is improved, but throughput is degraded

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidthroughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The UE initiates data transfer with the target secondary node before the random access procedure with the target master node completes. This preliminary data transfer action improves throughput by utilizing the secondary node earlier, while reliability is maintained through mechanisms that handle potential master node procedure failures

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4038951B1Parallel handover and failure handling
Publication Date: 2026.01.28 QUALCOMM INC
  • EP4038951B1 patent drawingFigure 1
  • EP4038951B1 patent drawingFigure 2
  • EP4038951B1 patent drawingFigure 3

AI summary

Methods (1500, 1600, 1700, 1800, 1900), systems (1000, 1400) and devices (705, 805, 1005, 1105, 1205, 1405) for wireless communications are presented. A method (1500, 1600) may include the following operations. A UE determines to perform a handover from a first source device in a first network to a first target device in the first network and from a second source device in a second network to a second target device in the second network (1505, 1605). The UE identifies a time interval for performing a first random access procedure with the first target device in the first network (1510, 1610). The UE initiates a first random access procedure with the first target device (1515, 1615). The UE performs a second random access procedure successfully with the second target device in the second network during the time interval (1520, 1620). The UE transmits or receives from the target device in the second network before the UE finishes performing the first random access procedure with the first target device in the first network (1525, 1630).