Uplink Control Channel DTX Indicator Multiplexing

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Solution Overview

Problem

Conventional wireless communication systems fail to distinguish between decoding errors of downlink control and data channels when CQI and ACK/NAK information are multiplexed in the same uplink control channel subframe, leading to difficulties in detecting discontinuous transmission (DTX) and accurately reporting channel quality to the base station.

Innovation Solution

The solution involves encoding Channel Quality Indicator (CQI) information and a DTX indicator within an uplink control channel subframe, allowing the base station to differentiate between successful and unsuccessful decoding of the downlink control channel, and transmitting this information to facilitate DTX detection and improve HARQ retransmission strategies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CQI and ACK/NAK information are multiplexed in the same uplink control channel subframe, then uplink control channel efficiency is improved, but the ability to distinguish between control and data channel decoding errors deteriorates

Engineering Contradiction:
Improveuplink control channel efficiencyVSAvoiderror detection capability
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the error detection capability by introducing a separate DTX indicator that specifically identifies control channel decoding errors, distinct from the ACK/NAK indicators for data channel errors. This segmentation allows the system to maintain multiplexing efficiency while preserving the ability to distinguish between different types of decoding errors through separate signaling mechanisms.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If conventional multiplexing is used without DTX indication, then signaling overhead is reduced, but the base station cannot identify control channel decoding failures

Engineering Contradiction:
Improvesignaling overheadVSAvoidcontrol channel error detection
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a DTX indicator as an intermediary element that mediates between the uplink control channel and the base station. This intermediary provides explicit information about control channel decoding status without significantly increasing overall signaling overhead, as it can be integrated into existing uplink control channel structures such as PUCCH or PUSCH transmissions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If DTX indicator is added to distinguish control channel errors, then error detection accuracy is improved, but uplink control channel complexity increases

Engineering Contradiction:
Improveerror detection accuracyVSAvoidcontrol channel encoding complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the DTX indicator with existing uplink control channel structures, combining it with CQI and ACK/NAK information in the same transmission resource. This merging approach allows the system to achieve improved error detection accuracy while minimizing the increase in encoding complexity by utilizing existing multiplexing frameworks rather than creating entirely separate signaling channels.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2250755B1Discontinuous transmission signaling over an uplink control channel
Publication Date: 2014.12.31 QUALCOMM INC
  • EP2250755B1 patent drawingFigure 1
  • EP2250755B1 patent drawingFigure 2
  • EP2250755B1 patent drawingFigure 3

AI summary

Systems and methodologies are described that facilitate signaling and detecting discontinuous transmission (DTX) in a wireless communication environment. A DTX indicator and Channel Quality Indicator (CQI) feedback can be multiplexed within a common uplink control channel subframe and transmitted to a base station when the access terminal is operating in DTX mode for an Acknowledgement Channel. Further, when operating in non-DTX mode, the access terminal can multiplex an ACK indicator or a NAK indicator with the CQI feedback within a common uplink control channel subframe, which can thereafter be transferred to the base station. Accordingly, the base station can detect DTX operation or non-DTX operation of the access terminal. For example, reference signal symbols can carry one of the DTX indicator, the ACK indicator, or the NAK indicator. Pursuant to another example, the CQI feedback and the DTX indicator can be combined and carried jointly by non-reference signal symbols.