Adaptive Radio Resource Selection for D2D RTT Stabilization

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Solution Overview

Problem

In device-to-device communications, the round-trip transmission time (RTT) is unstable and difficult to control due to dependence on radio access layers that lack information on experienced RTT, leading to performance issues in applications requiring timely responses.

Innovation Solution

A user equipment selects radio resources for transmitting a response packet based on a selection window whose size is dependent on the time duration related to the received packet, allowing for adaptive adjustment of RTT to a target value by starting the selection window before or after the generation of the response packet, thereby reducing the delay and stabilizing the RTT.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a classical radio resource selection with a fixed Packet Delay Budget (PDB) is used, then the resource selection process is simple and straightforward, but the Round-Trip Time (RTT) becomes unstable and unpredictable

Engineering Contradiction:
Improveradio resource selection processVSAvoidRTT stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the selection window size adaptive rather than fixed. The selection window dynamically adjusts its size based on the time duration related to the received packet, allowing the system to adapt RTT characteristics to different communication conditions while maintaining operational simplicity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of selection window size from a fixed PDB value to a variable dependent on the time duration related to the received packet. This parameter change enables the system to control RTT stability by adjusting the selection window size according to actual communication conditions

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the selection window size is reduced to stabilize RTT, then the RTT becomes more predictable and stable, but the available radio resources for transmission are reduced

Engineering Contradiction:
ImproveRTT stabilityVSAvoidavailable radio resources
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The selection window size dynamically adapts based on the time duration related to the received packet. When RTT stability is prioritized, the window is reduced; when more resources are needed, the window can be enlarged, creating a dynamic balance between stability and resource availability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the selection window size parameter based on communication conditions. By making this parameter variable rather than fixed, the system can optimize the balance between RTT stability and available radio resources according to specific scenario requirements

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the selection window starts after the generation of the response packet, then the resource selection is simpler to implement, but the RTT delay increases

Engineering Contradiction:
Improveimplementation complexityVSAvoidRTT delay
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent applies preliminary action by allowing the selection window to start before the response packet generation is complete. This enables radio resources to be selected in advance, reducing the overall RTT delay while maintaining manageable implementation complexity through proper timing coordination

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4354988A1Packet-based dynamic resource allocation
Publication Date: 2024.04.17 MITSUBISHI ELECTRIC R&D CENTRE EUROPE BV
  • EP4354988A1 patent drawingFigure 1
  • EP4354988A1 patent drawingFigure 2.1
  • EP4354988A1 patent drawingFigure 2.2

AI summary

The invention relates to a method to transmit by a user equipment a response backward packet (BWP) in response to a received forward packet (FWP) (S36) received from another user equipment in a D2D communication, comprising: Receive from the another user equipment by the user equipment the received packet (FWP); Perform by the user equipment radio resource selection used to transmit the response packet (BWP), the radio resources selected are selected among radio resources in a selection window such as the delay between the reception of the received packet and a last radio resource of the radio resources in the selection window is dependent on a time duration related to the received packet (FWP); Send by the user equipment to the another user equipment the response packet using at least one resource among the selected radio resources.