Dynamic TDD UL/DL Configuration HARQ Timing Continuity

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Solution Overview

Problem

Current LTE TDD systems face inefficiencies in radio resource utilization due to fixed UL/DL configurations, leading to issues with HARQ timing linkage disruptions during configuration changes, which affect both downlink and uplink transmissions.

Innovation Solution

The method involves dynamically reconfiguring TDD UL/DL configurations based on HARQ ACK/NACK indicators, allowing for flexible changes while maintaining HARQ timing continuity by limiting permissible configuration combinations and using adaptive PUSCH retransmissions to ensure seamless transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fixed UL/DL configurations are used in LTE TDD systems, then system stability is maintained, but radio resource utilization efficiency deteriorates

Engineering Contradiction:
Improveradio resource utilization efficiencyVSAvoidconfiguration flexibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic TDD UL/DL configuration changes, allowing the system to transition from fixed to adaptive configurations. The base station can dynamically adjust UL/DL configuration based on traffic conditions while maintaining HARQ timing relationships, thereby improving radio resource utilization efficiency without compromising system stability.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If dynamic configuration changes are implemented, then configuration flexibility is improved, but HARQ timing linkage disruptions occur

Engineering Contradiction:
Improveconfiguration flexibilityVSAvoidHARQ timing continuity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by pre-planning HARQ timing relationships before configuration changes. The system identifies permissible configuration combinations that maintain valid HARQ timing, and selects target configurations that do not disrupt existing HARQ processes, thereby preventing timing linkage disruptions before they occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent introduces configuration combination tables as intermediaries that map source configurations to permissible target configurations. These tables serve as mediators that ensure configuration changes maintain valid HARQ timing relationships, acting as a bridge between dynamic configuration needs and HARQ timing requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If configuration changes are made to improve resource efficiency, then productivity increases, but transmission delays increase due to HARQ disruptions

Engineering Contradiction:
Improveradio resource usage efficiencyVSAvoidHARQ transmission delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary identification of permissible configuration combinations before actual configuration changes. By pre-determining which target configurations maintain valid HARQ timing relationships, the system avoids configuration changes that would cause HARQ disruptions and subsequent retransmissions, thereby preventing time loss.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2654235B1HARQ For Dynamic Change of the TTD UL/DL Configuration in LTE TDD Systems
Publication Date: 2017.12.20 BLACKBERRY LTD
  • EP2654235B1 patent drawingFigure 1A~1B
  • EP2654235B1 patent drawingFigure 2
  • EP2654235B1 patent drawingFigure 3~4

AI summary

Systems, methods, and apparatuses are directed to reconfiguring a time division duplex (TDD) uplink/downlink (UL/DL) configuration. A first TDD UL/DL configuration can be identified for a first radio frame. A second TDD UL/DL configuration can be identified for a second radio frame adjacent the first radio frame. The second TDD UL/DL configuration can be identified based, at least in part, on one or more subframes of the second TDD UL/DL configuration that can communicate hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicators for corresponding subframes of the first TDD UL/DL configuration.