Inter-carrier D2D Resource Allocation via Gap Requests

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Solution Overview

Problem

Existing approaches to multi-carrier D2D communication face challenges in reducing interruptions to UL transmissions and efficiently sharing transmitter chains between D2D and cellular uplink transmissions, particularly in inter-PLMN and out-of-network coverage scenarios, due to increased UE capability requirements and performance degradation.

Innovation Solution

A method where a wireless device determines time resources from pools for sidelink operations, sends a gap request message to a network node, and receives resource allocation configurations to manage sidelink transmissions, allowing for efficient time-sharing of transmitter chains and minimizing interruptions to UL transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multi-carrier D2D communication is implemented, then spectral efficiency and resource utilization are improved, but interruption to UL transmissions increases

Engineering Contradiction:
Improvespectral efficiencyVSAvoidinterruption to UL transmissions
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent segments the time resources by introducing gap indicators that divide the time spectrum into D2D transmission gaps and UL transmission portions. This segmentation allows the system to allocate specific time slots for D2D operations while preserving other slots for UL transmissions, thereby reducing interruptions to UL while maintaining high spectral efficiency through parallel D2D operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic resource allocation where the network node adaptively adjusts gap configurations based on traffic conditions. The gap request message and gap configuration enable the system to dynamically modify D2D time resources in response to changing UL traffic demands, optimizing the balance between D2D spectral efficiency and UL transmission continuity.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If transmitter chains are shared between D2D and cellular uplink transmissions, then device complexity is reduced, but transmission performance degrades

Engineering Contradiction:
Improvetransmitter chain configurationVSAvoidtransmission performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs periodic time-gap patterns for D2D transmissions, allowing the transmitter chain to alternately serve D2D and cellular uplink functions in a regular cycle. This periodic switching reduces the need for multiple simultaneous transmitter chains while maintaining transmission performance by ensuring adequate recovery and switching time between D2D and cellular modes.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The network node acts as an intermediary that coordinates transmitter chain usage between D2D and cellular functions. Through gap request messages and gap configurations, the network node mediates resource allocation, ensuring that the shared transmitter chain switches between modes optimally, thereby reducing device complexity while preserving transmission reliability through centralized coordination.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of information

If autonomous resource selection is used for D2D, then signaling overhead is reduced, but resource allocation efficiency decreases

Engineering Contradiction:
Improvesignaling overheadVSAvoidresource allocation efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent implements a hybrid approach where UEs autonomously select D2D time resources from gap configurations provided by the network. This self-service mechanism reduces signaling overhead compared to fully centralized allocation, as UEs independently choose resources within predefined gaps rather than requiring network approval for each selection.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The network node controls resource allocation efficiency by adjusting gap configuration parameters such as gap duration, frequency, and timing. These parameter changes enable the system to optimize resource allocation efficiency while maintaining reduced signaling overhead, as the network only needs to signal gap parameters rather than individual resource assignments.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3691362B1Inter-carrier d2d resource allocation
Publication Date: 2022.07.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3691362B1 patent drawingFigure 1
  • EP3691362B1 patent drawingFigure 2
  • EP3691362B1 patent drawingFigure 3

AI summary

A method in a wireless device (110) is disclosed. The method comprises determining (504) one or more time resources in a particular carrier from one or more pools of time resources for a sidelink operation by the wireless device (110). The method comprises sending (508) a gap request message to a network node (115), the gap request message indicating one or more gaps requested by the wireless device (110), the one or more gaps comprising the determined one or more time resources for the sidelink operation.