Dynamic RACH-DAMA Switching for Sporadic Uplink Traffic

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Solution Overview

Problem

Current methods for transmitting data packets between a contention channel RACH and a channel with resource reserved on request DAMA are inefficient for sporadic and unpredictable small data traffic, with the RACH channel being underutilized and prone to delays.

Innovation Solution

A method that dynamically adapts the capacity of the contention channel by routing data packets or fragments based on real-time information about available resources, using a combination of contention access and demand reservation access modes, and implementing packet classification, fragmentation, and encapsulation protocols to optimize transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data packets are transmitted using contention channel RACH for sporadic traffic, then channel utilization is improved, but transmission delays increase due to random access conflicts

Engineering Contradiction:
Improvechannel utilizationVSAvoidtransmission delays
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements dynamic switching between RACH contention mode and DAMA reservation mode based on real-time queue status and channel conditions. The terminal adaptively changes access mode: using RACH when queue is below threshold and channel is available, switching to DAMA when queue exceeds threshold or RACH fails, thereby optimizing both channel utilization and transmission delay dynamically

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the access mode parameter from static to dynamic by introducing threshold-based switching mechanisms. The terminal monitors queue length parameters and channel state parameters, adjusting the access mode parameter accordingly to resolve the contradiction between utilization and delay

Inventive Principle:
Principle #35Parameter changes

2Productivity

If data packets are routed based on real-time resource information, then transmission efficiency is improved, but system complexity increases due to information management requirements

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The terminal autonomously monitors its own queue status and selects access modes based on pre-configured thresholds without requiring complex centralized control. The system uses simple self-service mechanisms: queue length comparison with thresholds, automatic mode switching, and local decision-making, which improves efficiency while keeping complexity manageable at the terminal level

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent segments the data transmission process into distinct modes (RACH contention mode and DAMA reservation mode) with clear switching criteria. By dividing the access mechanism into separable modes with defined transition conditions, the system achieves efficient resource utilization while maintaining manageable complexity through modular design

Inventive Principle:
Principle #1Segmentation

3Productivity

If RACH channel is used for small data packets, then resource allocation is optimized, but packet loss increases due to contention conflicts

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidpacket loss rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary switching mechanism that mediates between RACH and DAMA modes. When RACH contention fails or queue exceeds threshold, the terminal uses DAMA as an intermediary fallback mode with guaranteed resource allocation, thereby reducing packet loss while maintaining overall resource allocation efficiency through the dual-mode architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3151623B1Method for transmitting switched data packets between a contention-based channel (RACH) and a demand assigned channel (DAMA)
Publication Date: 2018.05.16 THALES SA
  • EP3151623B1 patent drawingFigure 1
  • EP3151623B1 patent drawingFigure 2
  • EP3151623B1 patent drawingFigure 3

AI summary

A method for transmitting uplink data from a terminal TE chosen from among a plurality of terminals to a gateway GW switches data packets or packet fragments between a first contention access mode and a second DAMA demand-reserved access mode. Each terminal TE routes (106) the data packets or packet fragments onto the contention channel RACH or onto a demand-reserved channel via DAMA demand access based on the packet size and their class of service, and representative information of the current transmission resources allocated to the contention channel RACH and the DAMA demand-reserved access mode, the representative information being notified to the terminals via a return channel.