Relay UE Handover Coordination for Service Continuity

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Solution Overview

Problem

In the context of evolved ProSe UE-to-Network Relay, ensuring that remote UE and relay UE are served by the same eNB to avoid the need for inter-eNB links and maintain service continuity during handovers, especially in scenarios where the UEs are moving and have different initial serving eNBs.

Innovation Solution

The method involves determining whether the remote UE and relay UE are served by the same eNB and, if not, initiating a handover to ensure they are served by the same eNB, either by relocating the remote UE or the relay UE, to facilitate efficient relaying and maintain service continuity during mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If relaying is initiated between remote UE and relay UE served by different eNBs, then connectivity can be established, but inter-eNB links are required which increase latency and packet loss

Engineering Contradiction:

Improveservice continuityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary checks to determine whether the remote UE and relay UE are served by the same eNB before initiating relaying. This preliminary action prevents the establishment of relaying connections that would require inter-eNB links, thereby avoiding the associated latency and packet loss issues from the outset

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If relaying is initiated between remote UE and relay UE served by different eNBs, then connectivity can be established, but inter-eNB links are required which increase complexity

Engineering Contradiction:

Improverelay establishmentVSAvoidinter-eNB link requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs preliminary verification to check whether the remote UE and relay UE share the same serving eNB before establishing relaying. This preliminary check ensures that relaying is only initiated when it can operate without requiring complex inter-eNB links, thus reducing system complexity while maintaining adaptability

Inventive Principle:

Principle #10Preliminary action

3Reliability

If handover is initiated for remote UE or relay UE, then service continuity can be maintained, but additional signaling and coordination are required

Engineering Contradiction:

Improveservice continuity during mobilityVSAvoidhandover coordination

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system implements feedback mechanisms where the eNB monitors the serving status of both remote UE and relay UE. When a handover is detected or anticipated, the eNB coordinates the handover process for both UEs to ensure they remain served by the same eNB, maintaining service continuity while managing the complexity through centralized control and feedback loops

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11470518B2Relaying between a user equipment and a network

Publication Date: 2022.10.11 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A radio access network comprises a first radio access node and a second radio access node. On determining that a first UE that is served by the first radio access node should start relaying through a second UE, it is determined whether the second UE is served by the first radio access node. In response to determining that the second UE is served not by the first radio access node but by the second radio access node, a handover is initiated, such that the first and second UEs are served by the same radio access node.