D2D Communication Mode Switching for Coverage Transitions

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Solution Overview

Problem

Device-to-device (D2D) communications in wireless networks face disruptions when user equipment (UE) transitions out of a base station's coverage area, leading to temporary radio link failures that can impact public safety operations.

Innovation Solution

Implementing a method for UEs to switch from a centralized transmission resource schedule to a distributed transmission schedule using a pool of resources allocated by the base station, with intermediate modes to manage transitions and maintain communication continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a centralized transmission resource schedule from a base station is used for D2D communications, then communication reliability is improved when within coverage area, but communication disruption occurs when transitioning out of coverage area

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcoverage area adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically switches between centralized scheduling mode (when base station coverage is available) and distributed scheduling mode (when out of coverage). This dynamic adaptation allows the D2D communication system to maintain reliability within coverage while gaining adaptability to operate autonomously outside coverage areas, resolving the contradiction between centralized control reliability and coverage area adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The base station acts as an intermediary that provides centralized scheduling when available, but the system is designed to transition to distributed scheduling when the intermediary is no longer accessible. This intermediary mechanism enables the system to achieve high reliability when the base station is present while maintaining adaptability to function independently when the base station coverage is lost.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a centralized transmission resource schedule is used, then resource allocation efficiency is improved, but communication continuity deteriorates during base station transitions

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidcommunication continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary switching to distributed scheduling mode before complete loss of base station connection occurs. By anticipating the transition and switching in advance, the system maintains resource allocation efficiency through centralized scheduling when available, while ensuring communication continuity by having the distributed mode ready to take over seamlessly, thus resolving the contradiction between efficiency and continuity.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If distributed transmission scheduling is used, then adaptability to coverage changes is improved, but resource allocation efficiency deteriorates compared to centralized scheduling

Engineering Contradiction:
Improvecoverage transition adaptabilityVSAvoidresource allocation efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system dynamically selects between centralized and distributed scheduling based on coverage conditions. Centralized scheduling is used when base station coverage is available to maximize resource allocation efficiency, while distributed scheduling is activated when transitioning out of coverage to maintain adaptability. This dynamic selection resolves the contradiction by applying each scheduling method in its optimal context.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3100546B1Switching mode of operation in d2d communications
Publication Date: 2019.06.12 QUALCOMM INC
  • EP3100546B1 patent drawingFigure 1
  • EP3100546B1 patent drawingFigure 2
  • EP3100546B1 patent drawingFigure 3

AI summary

Methods, systems, and devices are described for switching a mode of operations in device to device (D2D) communications. A UE within the coverage area of a base station may communicate directly with other UEs using a centralized transmission resource schedule. Prior to experiencing radio link failure (RLF), the UE may determine that switching parameters have been met and transition to an intermediate mode based on a distributed transmission schedule using a pool of resources established by the base station. In one example, the switching parameters may be received from the base station in a connection response message. In another example, the UE may send a switching request to the base station prior to initiating the transition to the intermediate mode. In some cases, after the transition to the intermediate mode, the UE may experience a radio link failure and transition to a distributed mode using a predetermined pool of resources.