Encrypted Relay Service Codes for Cellular Slice Privacy

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Solution Overview

Problem

The existing relay discovery and selection mechanisms in cellular sliced networks expose privacy-sensitive information, such as network slice and DNN identifiers, leading to potential tracking and security risks, especially for out-of-coverage UEs, due to the use of static Relay Service Codes and unencrypted discovery messages.

Innovation Solution

Implement a mechanism where Relay Service Codes are encrypted by a Network Relay Function (NRF) using keys that only the mobile device can decrypt, ensuring that even if messages are unencrypted, the relay device cannot track the mobile device, and only the selected relay device receives encrypted PDU session parameters, maintaining privacy and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Relay Service Codes are made static and discovery messages are unencrypted to simplify the relay selection process, then the ease of operation is improved, but privacy protection deteriorates as relay devices can track mobile devices

Engineering Contradiction:

Improverelay selection processVSAvoidprivacy exposure and tracking

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a Network Relay Function (NRF) as an intermediary that encrypts Relay Service Codes before sending them to relay devices. The NRF acts as a mediator between the mobile device and relay devices, ensuring that even though discovery messages remain unencrypted for simplicity, the relay service identification information is protected through encryption managed by the network function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the state of Relay Service Codes from unencrypted to encrypted form. By transforming the parameter of the Relay Service Code from plaintext to ciphertext, the system maintains ease of operation for relay selection while preventing privacy exposure and tracking of mobile devices.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If all relay devices receive encrypted PDU session parameters to ensure security, then privacy protection is improved, but device complexity increases due to encryption and key management

Engineering Contradiction:

Improveprivacy protectionVSAvoidencryption and key management

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing encrypted PDU session parameters only to the selected relay device rather than all relay devices. The encryption and key management complexity is localized to the communication between the mobile device and the selected relay, rather than being distributed across all relay devices in the network.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the distribution of encrypted parameters by first selecting a specific relay device and then providing encrypted PDU session parameters only to that selected relay. This segmentation isolates the security complexity to a single relay-device connection rather than affecting all relay devices.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If Relay Service Codes are encrypted to prevent tracking, then privacy protection is improved, but the difficulty of detecting and measuring increases due to encryption processing

Engineering Contradiction:

Improvetracking preventionVSAvoidrelay code identification

Core Design Contradiction:

Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The Network Relay Function serves as an intermediary that handles the encryption and decryption of Relay Service Codes. This mediator approach allows the mobile device to send unencrypted identification information to the NRF, which then encrypts it for transmission to relay devices, simplifying the detection and measurement process while maintaining privacy protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses encryption as a copying mechanism that transforms the Relay Service Code into an encrypted form that can be transmitted and processed. The encrypted code maintains the functional equivalent of the original code for identification purposes while preventing tracking, effectively creating a secure copy that preserves functionality without exposing privacy information.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS12445833B2Privacy of relay selection in cellular sliced networks

Publication Date: 2025.10.14 KONINKLIJKE PHILIPS NV

AI summary

A cellular communication system supports a Network Relay Function (140) for managing the indirect connections. A mobile device (110) may send a request message to a relay device (120), the request message including a relay service code (associated with a set of privacy sensitive PDU session parameters). The relay device receives the request message and sends a transfer request message to the cellular communication system indicating a request to transfer data via an indirect connection and including the requested relay service code. The Network Relay Function receives the transfer request message, determines a different relay service code to be used instead of the requested relay service code; and sends a transfer response message including the different relay service code in an encrypted manner that allows it to be decrypted by the mobile device, but not the relay device; and forwarding by the relay device the encrypted different relay service code to the mobile device in a response to the request message.