5G Multicast Session Release Signaling for Moving Users

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Solution Overview

Problem

Current broadcast systems face limitations in providing services to moving users or those in areas with complex orography and poor signal quality, necessitating improvements in 5G multicast/broadcast services to enhance user experience and reduce operational costs.

Innovation Solution

A method and network node for managing multicast sessions by receiving a message indicating session release, transmitting an indication to the UE, and handling session context management through SMF, AMF, and RAN nodes, utilizing 5G network components like MB-SMF, UPF, and RAN to facilitate efficient multicast session management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unicast transmission is used to provide services to moving users or users in areas with complex orography, then service coverage and signal quality are improved, but network capacity requirements and resource consumption increase substantially

Engineering Contradiction:

Improveservice delivery reliabilityVSAvoidnetwork capacity requirements

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple unicast transmissions into a single multicast transmission by establishing a shared PDU session that can serve multiple UEs simultaneously. The SMF creates a multicast PDU session that delivers the same data to multiple UEs over a shared transport connection, thereby reducing network capacity requirements while maintaining service delivery reliability to moving users and users in challenging environments.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The multicast PDU session mechanism provides multi-functionality by serving both unicast and multicast service requirements. The same PDU session infrastructure can handle individual UE communications while also supporting group communications, making the network more efficient for scenarios where multiple users in the same area receive identical content, thereby reducing overall network capacity requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If broadcast services are used to deliver content to unlimited devices, then network capacity requirements are reduced, but service interactivity and return channel capabilities are lost

Engineering Contradiction:

Improvenetwork capacity requirementsVSAvoidservice interactivity

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic service delivery by enabling the network to switch between unicast and multicast modes based on the number of active UEs. When few UEs are active, unicast transmission is used providing full interactivity. When many UEs are active, the system transitions to multicast transmission reducing network capacity requirements, while still maintaining the ability to establish return channels for interactive services when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The SMF acts as an intermediary that manages the transition between broadcast-like multicast efficiency and unicast interactivity. It monitors the number of active UEs and dynamically selects the appropriate transmission mode, thereby reducing network capacity requirements while preserving service interactivity through the ability to fall back to unicast or establish return channels when necessary.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If multicast transmission is used to serve multiple users with the same data, then resource allocation efficiency is improved, but session management complexity increases

Engineering Contradiction:

Improveresource allocation efficiencyVSAvoidsession management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where the SMF automatically monitors the number of active UEs and dynamically decides when to establish or release multicast PDU sessions based on predefined thresholds. This automated decision-making process reduces session management complexity by eliminating the need for manual intervention, allowing the system to efficiently allocate resources through self-adjusting multicast session creation and release based on actual network conditions.

Inventive Principle:

Principle #25Self-service

4Productivity

If multicast PDU sessions are dynamically created and released based on active UE thresholds, then network resource efficiency is improved, but session management overhead increases

Engineering Contradiction:

Improvenetwork resource efficiencyVSAvoidsession management overhead

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by pre-configuring threshold values that trigger multicast session creation or release. Instead of continuously monitoring and making real-time decisions, the system uses predetermined thresholds (e.g., when active UEs exceed threshold T1, create multicast session; when they fall below threshold T2, release multicast session). This approach improves network resource efficiency while reducing session management overhead by minimizing the frequency and complexity of management decisions.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250344288A1Multicast session management

Publication Date: 2025.11.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A network node, a UE, and methods for managing a multicast session for the UE. The method comprises: receiving, from an MB-SMF, a first message indicating that the multicast session is released; and transmitting, to the UE, a first indication indicating that the multicast session is released.