ACK Repetition Pattern for Wireless HARQ Reliability

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in data transmission due to unreliable ACK/NAK transmissions in HARQ processes, leading to delays and complex implementation issues, especially with variable length H-ARQ messages.

Innovation Solution

Implementing an efficient ACK/NAK repetition scheme using a specific transmission pattern in frequency and time to improve the reliability of ACK/NAK transmissions, which involves allocating resources based on a maximum repetition factor and using orthogonal sub-blocks for repeated ACK/NAK transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If HARQ process is used to improve data transmission reliability, then transmission reliability is improved, but system complexity increases due to variable length H-ARQ messages

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the ACK/NAK feedback into multiple fixed-size repetitions transmitted at different time instances. Instead of handling variable length H-ARQ messages as a single complex unit, the system divides the acknowledgment into discrete segments (repetitions) that can be independently transmitted and processed, simplifying the overall system complexity while maintaining reliability through diversity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If ACK/NAK transmission is repeated to improve reliability, then transmission reliability is improved, but transmission overhead increases

Engineering Contradiction:
ImproveACK/NAK transmission reliabilityVSAvoidtransmission overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent employs periodic repetition of ACK/NAK transmissions at predetermined time intervals. This periodic action allows the system to achieve reliability through multiple transmission opportunities while maintaining efficient resource utilization. The repetitions are scheduled systematically, avoiding random retransmissions and reducing overall overhead compared to unscheduled retransmission schemes.

Inventive Principle:
Principle #19Periodic action

3Productivity

If ACK/NAK transmission delay is reduced to improve system performance, then productivity is improved, but transmission reliability may deteriorate

Engineering Contradiction:
Improvedata delivery speedVSAvoidACK/NAK transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent prepares multiple ACK/NAK repetition instances in advance at predetermined time instances. By having pre-scheduled transmission opportunities ready, the system can quickly transmit acknowledgments without waiting for dynamic scheduling decisions, thus reducing delay while maintaining reliability through the pre-prepared multiple transmission opportunities.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2372939B1Method and apparatus for acknowledgment repetition in orthogonal systems
Publication Date: 2020.09.23 QUALCOMM INC
  • EP2372939B1 patent drawingFigure 1
  • EP2372939B1 patent drawingFigure 2
  • EP2372939B1 patent drawingFigure 3

AI summary

A method and apparatus for a wireless communication system, using a repetition factor to determine how many times a acknowledgement should be repeated in response to receiving a first data transmission, selecting an acknowledgement transmission (ACK TX) pattern, wherein the ACK TX pattern comprises of resources information of a plurality of blocks used for transmitting the first acknowledgement, and transmitting, repeatedly, the acknowledgements according to the ACK TX pattern.