D2D Gap Configuration for Discovery Signal Management

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Solution Overview

Problem

Current wireless communication systems, particularly LTE, lack direct communication capabilities essential for public safety networks, which require stringent reliability and security, especially in situations where cellular coverage is unavailable, and do not effectively support device-to-device (D2D) operations necessary for proximity-based services.

Innovation Solution

A method for a user equipment (UE) to transmit information about its interest and capabilities for D2D operations to the network, allowing the network to manage and prioritize D2D operations, including frequency allocation, service preferences, and power control, enabling efficient D2D communication even when out of traditional cellular coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If D2D operations are implemented in LTE to enable direct communication for public safety networks, then service availability and reliability are improved, but interference with existing cellular systems and resource conflicts increase

Engineering Contradiction:
Improveservice availabilityVSAvoidinterference with cellular system
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the uplink frequency band into dedicated D2D resources and traditional cellular resources. By dividing the frequency spectrum and allocating specific subframes, subchannels, and resource blocks for D2D operations, the system enables direct communication while preventing interference with cellular uplink transmissions. This segmentation allows simultaneous operation of both D2D and cellular services without mutual interference.

Inventive Principle:
Principle #1Segmentation

2Productivity

If D2D discovery signals are transmitted frequently to enable proximity-based services, then service quality and responsiveness are improved, but resource consumption and collision probability increase

Engineering Contradiction:
Improveservice responsivenessVSAvoidresource consumption
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent implements periodic transmission of D2D discovery signals at configured intervals rather than continuous transmission. The network configures specific discovery reference signal (DRS) periods, allowing UEs to transmit discovery signals only at designated times. This periodic approach maintains service responsiveness by regularly updating proximity information while significantly reducing overall resource consumption compared to continuous transmission.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The network pre-configures D2D discovery resources including time slots, frequency channels, and transmission parameters before D2D operations begin. By preliminarily allocating specific subframes, subchannels, and resource blocks for discovery signals, the system enables rapid D2D establishment when needed while avoiding resource conflicts. The preliminary configuration ensures that discovery signals are transmitted only when and where required, optimizing resource utilization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3461156B1D2d gap for d2d discovery signal
Publication Date: 2020.12.09 LG ELECTRONICS INC
  • EP3461156B1 patent drawingFigure 1
  • EP3461156B1 patent drawingFigure 2
  • EP3461156B1 patent drawingFigure 3~4

AI summary

A method for operating a user equipment, UE, in a wireless communication system is proposed, which comprises: transmitting a message including information which informs that the UE wants to transmit and/or receive a device-to-device, D2D, discovery signal to a network; receiving information on a D2D gap; and transmitting, to another UE, and/or receiving, from another UE, the D2D discovery signal in the D2D gap.