PC5 Layered Discovery Messages for Layer 2 and Layer 3 Relay Support

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Solution Overview

Problem

Existing communication systems, such as LTE and NR, primarily support layer-three relaying and lack a comprehensive solution for expanding relaying types in sidelink discovery messages to include layer-two relaying, limiting the versatility and flexibility of UE communication.

Innovation Solution

The generation of sidelink discovery messages involves generating message content through both the PC5-S and PC5-RRC layers, allowing for the support of both layer-two and layer-three relaying types by packaging the content across these layers, including relaying-terminal-selection conditions to facilitate UE discovery and relay selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If discovery messages only include relay selection conditions at the PC5-S layer, then the message structure remains simple, but the supported relaying types are limited to layer-three relay only

Engineering Contradiction:
Improvesupported relaying typesVSAvoidmessage structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the relay selection conditions into two distinct parts: PC5-S layer relay selection conditions and PC5-RRC layer relay selection conditions. This segmentation allows each layer to contribute specific relaying type information independently, enabling support for both layer-two and layer-three relaying while maintaining clear separation of concerns and manageable complexity in the overall message structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent embeds the PC5-RRC layer relay selection conditions within the PC5-S layer discovery message structure. The PC5-RRC conditions are packaged as a container or nested element inside the PC5-S message, allowing the multi-layer information to be transmitted through a single discovery message while preserving the hierarchical relationship between layers and avoiding excessive structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If relay selection conditions are added at both PC5-S and PC5-RRC layers, then both layer-two and layer-three relaying are supported, but the message content generation and processing complexity increases

Engineering Contradiction:
Improverelaying type coverageVSAvoidmessage generation ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The message generation process is segmented into two independent stages: PC5-S layer message content generation and PC5-RRC layer message content generation. Each layer generates its own relay selection conditions independently based on its specific requirements, which simplifies the generation logic for each layer while achieving comprehensive relaying type coverage when the segments are combined.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The PC5-RRC layer message content is packaged as a nested container within the PC5-S layer discovery message. This nesting approach allows the complex multi-layer content to be generated separately and then systematically integrated, reducing the overall processing complexity by avoiding the need to generate and manage all message elements in a single complex process.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4325908B1Generation method and apparatus and analysis method and apparatus for discovery message, device, and storage medium
Publication Date: 2025.07.23 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4325908B1 patent drawingFigure 1~2
  • EP4325908B1 patent drawingFigure 3
  • EP4325908B1 patent drawingFigure 4

AI summary

A generation method and apparatus and an analysis method and apparatus for a discovery message, a device, and a storage medium, which relate to the technical field of communications. The generation method is performed by a first terminal device, and comprises: generating message content by means of at least one layer among a PC5-S layer and a PC5-RRC layer (202); and by means of the PC5-S layer, encapsulating the message content into a discovery message (204). Since some message content is generated in the PC5-RRC layer and some message content is generated in the PC5-S layer, a supported relay type may be expanded by means of message content of different layers, such as supporting a layer 2 relay and a layer 3 relay.