D2D Relay Selection Using Candidate Status Feedback

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Solution Overview

Problem

Current D2D communication systems face challenges in identifying suitable UE within network coverage to act as relay UEs for transmitting data from UE outside network coverage to a base station.

Innovation Solution

A method where the source UE sends a first message to multiple candidate UEs within network coverage, receiving status information from each, and determines the most suitable UE based on criteria such as memory usage, power supply, processing capability, or link status to relay data to the base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the source UE sends a relay request to multiple candidate UEs and waits for responses, then the reliability of relay selection is improved, but the signaling overhead and time delay increase

Engineering Contradiction:
Improverelay selection reliabilityVSAvoidrelay discovery time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having candidate UEs pre-monitor for relay requests and have their relay capability information (memory usage, power supply status, processing capability, link status) pre-prepared and ready for immediate response. When a relay request is received, the candidate UE can quickly determine and respond with its suitability status without needing to gather this information in real-time, thus reducing the overall relay discovery time while maintaining reliable multi-UE evaluation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having candidate UEs send response messages back to the source UE indicating their relay suitability status. This feedback mechanism allows the source UE to make an informed selection based on actual status information from multiple candidates, improving reliability. The feedback includes specific parameters like memory usage, power supply status, and link quality, enabling the source UE to select the most appropriate relay UE

Inventive Principle:
Principle #23Feedback

2Reliability

If the source UE sends a relay request to multiple candidate UEs and waits for responses, then the reliability of relay selection is improved, but the signaling overhead increases

Engineering Contradiction:
Improverelay selection reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential relay suitability information from candidate UEs and includes it in compact response messages. Instead of exchanging extensive signaling sequences, the response messages contain specific extracted parameters (memory usage, power supply status, processing capability, link status) that directly indicate relay suitability. This extraction approach reduces signaling overhead while maintaining the ability to make reliable relay selection decisions

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by having candidate UEs send response messages only when they are suitable for relay service, rather than all candidate UEs responding regardless of suitability. The source UE sends relay requests to multiple candidates, but only those meeting certain criteria send responses, reducing overall signaling overhead while still maintaining reliable selection through multi-UE evaluation

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the source UE selects relay UE based on comprehensive status information, then the reliability of data transmission is improved, but the complexity of the selection process increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidrelay selection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by having different candidate UEs exhibit different status characteristics (memory usage, power supply, processing capability, link status) that are specific to their local conditions. The source UE evaluates these local quality parameters from each candidate and selects the relay UE whose local status best matches the requirements for reliable data transmission. This allows reliable selection without requiring a complex centralized control mechanism

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by monitoring and comparing key status parameters (memory usage, power supply status, processing capability, link status) of candidate UEs. The source UE selects the relay UE based on these parameters, which dynamically change based on the current state of each candidate. This parameter-based selection approach provides a systematic yet relatively simple method to achieve reliable relay selection without complex decision logic

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3322221B1D2d data transmission method, device and system
Publication Date: 2021.04.07 HUAWEI TECH CO LTD
  • EP3322221B1 patent drawingFigure 1
  • EP3322221B1 patent drawingFigure 2
  • EP3322221B1 patent drawingFigure 3A

AI summary

Embodiments of the present invention provide a D2D data transmission method and system, and a device, so as to resolve at least a prior-art problem about how to find UE in network coverage that can be used as relay UE, to transmit information from UE out of network coverage to a base station. The method includes: sending, by source UE, a first message to n candidate UEs, where the first message is used to indicate that the source UE needs to transmit data to a base station, the source UE is UE out of a network coverage area of the base station, and the n candidate UEs are UEs in the network coverage area of the base station; receiving, by the source UE, n second messages from the n candidate UEs, where each of the n candidate UEs sends one second message to the source UE, and the second message includes a user identity of each candidate UE and/or status information of each candidate UE; determining, by the source UE, relay UE from the n candidate UEs according to the user identity of each candidate UE and/or the status information of each candidate UE; and transmitting the data to the base station by using the relay UE. The present invention is applicable to the field of wireless communications.