vRAN Distributed Unit Handover for Maintenance Without Session Loss

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Solution Overview

Problem

Existing cellular networks, particularly virtual RANs, struggle to handle planned and unplanned instances of distributed units going down without interrupting communication sessions, especially in telecommunication environments where a single radio unit is used to relay communications between user equipment and a cloud computing system.

Innovation Solution

Implementing a middlebox migration system that facilitates a planned handover between distributed units in a vRAN environment, ensuring compliance with hard handover requirements in 5G networks by preparing for and executing a quick and reliable inter-distributed unit handover, including establishing SCTP connections in low-power mode to minimize resource consumption and service interruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If distributed units are upgraded or maintained in existing cellular networks, then system maintenance and updates can be performed, but communication sessions are interrupted and service continuity is lost

Engineering Contradiction:

Improvedistributed unit maintenance and upgrade capabilityVSAvoidcommunication session continuity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The system performs preliminary actions by establishing a second connection to a second distributed unit before deactivating the first connection. The second distributed unit is prepared in advance with necessary context information, and the handover is triggered only when ready, ensuring seamless transition without service interruption during maintenance operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A handover trigger acts as an intermediary component that coordinates the transition between distributed units. It receives maintenance initiation signals, manages the handover process between the first and second distributed units, and ensures proper state transfer, thereby enabling maintenance while maintaining service continuity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a single radio unit is used to relay communications, then network complexity is reduced, but resiliency and ability to handle distributed unit failures are compromised

Engineering Contradiction:

Improvenetwork architecture complexityVSAvoidnetwork resiliency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system implements local quality by enabling each distributed unit to have specific roles (first distributed unit for active service, second distributed unit for standby or maintenance). The handover trigger and connection management are localized to specific network elements, allowing targeted failover without requiring complete system redesign, thus maintaining simplicity while improving resiliency

Inventive Principle:

Principle #3Local quality

3Reliability

If handover between distributed units is implemented, then service continuity is maintained during maintenance, but additional system complexity and coordination requirements are introduced

Engineering Contradiction:

Improveservice continuity during maintenanceVSAvoidhandover coordination complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system reduces handover coordination complexity by performing preliminary actions - the second connection is established and the second distributed unit is prepared in advance with necessary context. This pre-positioning of resources eliminates the need for complex real-time coordination during the actual handover execution

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The handover trigger and connection management enable the system to self-service during maintenance operations. The second distributed unit autonomously assumes the role of the first distributed unit after handover, managing its own activation and context adoption without requiring extensive external coordination, thereby simplifying the overall system complexity

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12556993B2Distributed unit architecture for performing handover between distributed units in a VRAN

Publication Date: 2026.02.17 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

The present disclosure relates to systems, methods, and computer-readable media for increasing resiliency in distributed units of a virtual radio access network (vRAN) of a telecommunications network (e.g., a 5G telecommunications network), particularly when performing a planned handover operation between the distributed units. The examples described herein specifically relate to implementing an inter-distributed unit handover between distributed units that are serviced by the same radio unit. In some examples, this handover is initiated by a middlebox entity that is positioned between the distributed units and a centralized unit. In some instances, features of the middlebox entity are implemented within the framework of a centralized unit. By allowing a quick handover as described herein, the distributed units can provide uninterrupted service to a UE while allowing the distributed units to perform various upgrades or modifications to the distributed unit without service interruptions.