DTX Indicator Bit in HARQ Feedback for Wireless Signaling

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in distinguishing between Discontinuous Transmission (DTX) NoRx and NACK events, leading to inappropriate power settings and encoding choices, which affects HARQ operation and cell throughput.

Innovation Solution

A method and apparatus for user equipment in wireless communication networks that includes processing logic to signal DTX information, using a single indicator bit in HARQ feedback messages to differentiate between DTX NoRx and NACK events, allowing the eNB to adjust power and encoding accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a single indicator bit is used to signal DTX information in HARQ feedback messages, then the overhead is minimized and latency is reduced, but the ability to provide detailed differentiation between DTX NoRx and NACK events is limited

Engineering Contradiction:
ImprovelatencyVSAvoidDTX event differentiation information
Core Design Contradiction:
Loss of timeVSLoss of information

Solution Approach 1:

The patent extracts only the essential DTX indication information from the full DTX event detail, using a single indicator bit to signal the presence of DTX without transmitting complete event differentiation data. This selective extraction minimizes feedback overhead and latency while providing sufficient information for the eNB to identify DTX events and adjust power/encoding accordingly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a simple, low-cost single-bit indicator that can be quickly transmitted and discarded after serving its purpose of alerting the eNB to a DTX event. This disposable approach to information signaling reduces complexity and latency compared to transmitting detailed event differentiation data structures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If no DTX signaling is provided, then the feedback message structure remains simple, but the eNB cannot distinguish between DTX NoRx and NACK events, leading to inappropriate power settings and encoding choices

Engineering Contradiction:
Improvefeedback message structureVSAvoidHARQ operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism where a single indicator bit provides the eNB with essential information about DTX events. This feedback allows the eNB to adjust its power settings and encoding choices appropriately, improving HARQ reliability while maintaining a simple feedback message structure that does not significantly increase device complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the state of the feedback message by introducing a single indicator bit parameter that can take different values to indicate DTX events. This minimal parameter change enables the eNB to distinguish between DTX NoRx and NACK events without fundamentally altering the feedback message structure, thereby improving reliability with minimal complexity increase.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If detailed DTX event differentiation information is transmitted, then the eNB can accurately identify DTX NoRx events and adjust power and encoding, but the overhead increases and HARQ efficiency decreases

Engineering Contradiction:
ImproveDTX event identification accuracyVSAvoidHARQ efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the critical DTX indication from detailed event differentiation information, using a single indicator bit to signal DTX presence. This extraction provides sufficient precision for the eNB to identify DTX events and adjust power/encoding while minimizing overhead and maintaining HARQ efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by transmitting only the essential DTX indication rather than complete event differentiation details. This partial information transmission achieves adequate measurement precision for power and encoding adjustments while avoiding the overhead penalties that would reduce HARQ efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2591569B1Efficient signaling of discontinuous transmission
Publication Date: 2017.04.19 BLACKBERRY LTD
  • EP2591569B1 patent drawingFigure 1~2
  • EP2591569B1 patent drawingFigure 3~4
  • EP2591569B1 patent drawingFigure 5~7

AI summary

Methods and devices are disclosed for efficient signaling of discontinuous transmission in a wireless communication system. In various aspects of the disclosure, a user equipment device monitors transmissions on a plurality of physical downlink control channels (PDCCHs) and, in response to said transmissions, generates an acknowledge/negative acknowledge (ACK/NACK) signal comprising a plurality of bits, wherein the plurality of bits includes a discontinuous transmission (DTX) indicator bit. In some embodiments, the indicator bit corresponds to an even or odd number of PDCCHs successfully decoded. In other embodiments, the indicator bit corresponds to an odd or even number of component carriers comprising "TRUE" NACKs.