UE-to-Network Relay via N3IWF for Secure PC5 Sidelink Access

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Solution Overview

Problem

Existing wireless communication systems face challenges in securely relaying data between a remote UE and a network entity via a non-3GPP inter-working function (N3IWF) for Layer-3 UE-to-Network Relay, particularly in ensuring end-to-end security and efficient data transmission.

Innovation Solution

Implementing a method and device for wireless communication that establishes a connection with a network entity, determines support for sidelink relay access, indicates relay capabilities, and relays data between a remote UE and the network entity via an inter-working function device based on request.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a remote UE connects to the network via a relay UE over PC5 sidelink interface, then connectivity is extended to remote devices, but security risks increase due to indirect access paths

Engineering Contradiction:
Improveconnectivity extensionVSAvoidsecurity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an N3IWF (Non-3GPP InterWorking Function) as an intermediary security gateway between the relay UE and the 5G core network. This intermediary establishes IPsec security associations to protect user plane traffic, ensuring that even though the remote UE accesses the network indirectly through PC5 sidelink, the data transmission remains secure with end-to-end encryption between the relay UE and N3IWF.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If Layer-3 UE-to-Network Relay is implemented, then remote UE can establish NAS connections, but system complexity increases due to additional protocol layers

Engineering Contradiction:
ImproveNAS connection capabilityVSAvoidprotocol layer complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the communication system into distinct functional layers: the PC5 sidelink layer for direct UE-to-UE communication, the N3IWF layer for security and protocol translation, and the 5G core network layer for service management. This segmentation allows Layer-3 relay functionality to be implemented without requiring the entire system to handle complex protocols, as each layer operates with appropriate protocol complexity for its function.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple access types (N3IWF and PC5 relay) are supported simultaneously, then network access flexibility improves, but access management complexity increases

Engineering Contradiction:
Improveaccess type flexibilityVSAvoidaccess management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal access management framework at the N3IWF that can handle multiple access types (direct N3IWF access, PC5 relay access, and Layer-3 relay access) through a common interface and protocol. The N3IWF is designed with multi-functional capabilities to establish security associations and manage user plane traffic regardless of the access path, simplifying access management by providing a single point of control for diverse access methods.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4091397B1UE-to-network relay support for n3IWF access
Publication Date: 2026.04.22 QUALCOMM INC
  • EP4091397B1 patent drawingFigure 1
  • EP4091397B1 patent drawingFigure 2
  • EP4091397B1 patent drawingFigure 3

AI summary

Aspects relate to relaying data between a PC5 remote UE and a network entity via an inter-working function over sidelink UE-to-NW relay access. For example, a relay UE establishes a connection with the network entity and determines whether relay access to the network entity via an inter-working function device is supported at the relay UE. The relay UE then indicates, to the remote UE, support of the relay access to the network entity via the inter-working function device. The relay UE receives, from the remote UE, a request to relay data between the remote UE and the network entity via the inter-working function device, and thereafter, relays the data between the remote UE and the network entity via the inter-working function device based on the request.