Centralized Three-Party RTS/CTS for D2D Interference

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Solution Overview

Problem

Existing device-to-device (D2D) communication systems in cellular networks face interference challenges when operating in unlicensed bands, such as the 2.4 GHz ISM band, particularly when coexisting with WLAN systems, as conventional handshaking mechanisms like CSMA/CA do not adequately protect signaling interactions and resource allocation from interference.

Innovation Solution

A centralized three-party RTS/CTS exchange mechanism is introduced, where a central control unit initiates a three-party RTS/CTS exchange involving the central control device and two D2D devices, ensuring that D2D communication is only initiated if all parties confirm, thereby reducing interference from nearby WLAN terminals and maintaining control over resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If D2D communication operates in unlicensed bands using conventional handshaking mechanisms like CSMA/CA, then device-to-device communication can be established, but interference from WLAN systems and other unlicensed band users cannot be adequately prevented

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidinterference from WLAN systems
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing a three-party RTS/CTS handshaking mechanism where the central control unit proactively reserves resources and confirms communication readiness before actual D2D data transmission begins. This preliminary resource reservation and confirmation process prevents interference by ensuring the medium is clear and resources are allocated before transmission starts, rather than relying on reactive collision avoidance during transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a central control unit as an intermediary between D2D communicating devices. This intermediary coordinates the three-party RTS/CTS exchange, manages resource allocation, and ensures proper handshaking between devices. The central control unit acts as a mediator that resolves potential conflicts and prevents interference by orchestrating the communication process, rather than allowing direct peer-to-peer interaction without coordination.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If D2D communication is allowed without centralized control, then direct routing efficiency is improved, but resource allocation and interference coordination become unmanaged

Engineering Contradiction:
Improveresource usage efficiencyVSAvoidcontrol mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a communication system that can operate in multiple modes: it supports both traditional centralized cellular communication and D2D direct communication through the same infrastructure. The central control unit handles multiple functions including resource allocation, interference coordination, and D2D session management, making the system versatile without requiring separate dedicated systems for each communication type.

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

Solution Approach 2:

The patent implements self-service by enabling D2D devices to autonomously establish direct communication links once resources are allocated by the central control unit. The devices perform their own data transmission and reception without requiring continuous centralized intervention, allowing efficient direct routing while maintaining overall system coordination through the initial resource allocation framework.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If conventional two-party RTS/CTS handshaking is used between D2D devices, then direct communication is established, but signaling interactions remain vulnerable to interference from nearby WLAN terminals

Engineering Contradiction:
Improvecommunication setup simplicityVSAvoidinterference during signaling
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by extending the handshaking mechanism to include a third party (central control unit) that confirms resource availability and communication readiness before D2D signaling begins. This preliminary three-party confirmation ensures that the signaling channel is reserved and protected from interference before actual data transmission starts, preventing collisions during the vulnerable signaling phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces the central control unit as an intermediary in the RTS/CTS handshaking process. The central control unit receives and processes RTS signals, coordinates CTS responses, and ensures proper resource allocation before D2D communication begins. This intermediary role protects signaling interactions by adding an additional layer of coordination and conflict resolution that prevents WLAN interference during the handshaking phase.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2901798B1Methods, devices and computer program products improving device-to-device communication
Publication Date: 2020.01.22 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP2901798B1 patent drawingFigure 1
  • EP2901798B1 patent drawingFigure 2
  • EP2901798B1 patent drawingFigure 3

AI summary

The present invention proposes methods, devices and computer program products improving device-to-device communication. In order to improve D2D communication, the invention proposes a centralized communication concept involving a centralized control unit and those devices participating at the D2D communication. The concept involves a three-party RTS/CTS exchange.