RAN Node Failure Detection for Multicast Session Restoration

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Solution Overview

Problem

Current broadcast systems face challenges in providing reliable service to moving users and those in areas with complex orography or poor signal quality, necessitating improved methods for managing multicast/broadcast service sessions, especially with the introduction of 5G technologies.

Innovation Solution

A method and system for detecting and restoring multicast sessions at Radio Access Network (RAN) nodes experiencing failure or restart, involving the Session Management Function (SMF), Access and Mobility Management Function (AMF), and Multicast-Broadcast User Plane Function (MB-UPF) to ensure continuous service by re-establishing relevant resources and delivering multicast session data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If broadcast services are used to deliver content to multiple devices, then network capacity requirements and energy consumption are reduced, but service reliability deteriorates when RAN nodes experience failure or restart

Engineering Contradiction:

Improveenergy consumptionVSAvoidservice reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system performs preliminary actions by pre-configuring alternative RAN nodes and pre-establishing resource allocation plans before a failure occurs. When a RAN node fails, the SMF has already identified backup nodes and can quickly switch sessions without interruption, thus maintaining reliability while preserving the energy efficiency benefits of broadcast services.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The Session Management Function (SMF) acts as an intermediary between the multicast session and the RAN nodes. It monitors RAN node status, detects failures, and coordinates resource reallocation to backup nodes. This intermediary role enables the system to maintain service continuity during RAN failures while keeping the broadcast transmission path efficient.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If dedicated channels are established with each UE for unicast transmission, then service quality is maintained, but resource allocation efficiency deteriorates when many users consume the same data

Engineering Contradiction:

Improveservice qualityVSAvoidresource allocation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system segments the user base into two groups: those served through efficient broadcast/multicast channels and those requiring unicast due to mobility or signal issues. This segmentation allows the system to optimize for both resource efficiency (for broadcast users) and service quality (for unicast users), resolving the contradiction between the two transmission modes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the transmission mode for each UE based on real-time conditions such as mobility status and signal quality. Users can switch between broadcast and unicast modes as needed, allowing the system to maintain resource allocation efficiency while ensuring service quality for all users regardless of their specific conditions.

Inventive Principle:

Principle #15Dynamics

3Productivity

If broadcast services are used for content delivery, then network capacity requirements are reduced, but adaptability to moving users and users in complex orography deteriorates

Engineering Contradiction:

Improvenetwork capacityVSAvoidadaptability to moving users

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The system pre-configures multiple RAN nodes and establishes backup resource allocation paths before failures or mobility events occur. When a user moves or encounters signal issues, the system can quickly switch them to alternative nodes without interrupting service, thus maintaining network capacity efficiency while improving adaptability to moving users.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors user status, signal quality, and RAN node performance, using this feedback to dynamically adjust resource allocation. This feedback mechanism enables the system to maintain broadcast efficiency for stationary users while adapting to the needs of moving users or those in complex orography by switching to unicast modes when necessary.

Inventive Principle:

Principle #23Feedback

4Reliability

If RAN node resources are reallocated during failure recovery, then service continuity is improved, but restoration time increases due to resource establishment procedures

Engineering Contradiction:

Improveservice continuityVSAvoidrestoration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary resource allocation and configuration for backup RAN nodes before actual failures occur. When a failure is detected, the SMF can immediately activate pre-configured resources at backup nodes, significantly reducing restoration time while maintaining service continuity. This eliminates the need for time-consuming resource establishment procedures during recovery.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240422022A1Ran node failure/restart detection and restoration for multicast MBS session

Publication Date: 2024.12.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The disclosure is related to network nodes, a RAN node, and methods for detecting a failure/restart of the RAN node and methods for restoring a multicast session. The method at an SMF for detecting a failure and/or restart of a RAN node that serves one or more UEs for a multicast session comprises: receiving, from a network node, a message indicating a failure and/or restart of the RAN node.