HARQ Feedback Latency Reduction in Short TTI Scheduling

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Solution Overview

Problem

In 5G wireless communication networks, the transmission of latency-sensitive services is hindered by increased HARQ feedback latency due to the scheduling of short TTIs within long TTIs, leading to wasted resources and prolonged transmission times.

Innovation Solution

The method involves interrupting long TTI data transmission to schedule short TTIs, allocating HARQ feedback resources for each short TTI, and configuring scheduling information within the long TTI to enable timely data transmission and feedback, thereby reducing latency and improving transmission flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If short TTIs are scheduled within long TTIs using the long TTI HARQ feedback resource, then resource configuration is simplified, but HARQ feedback latency increases and transmission efficiency deteriorates

Engineering Contradiction:
ImproveHARQ feedback resource configuration complexityVSAvoidHARQ feedback latency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent divides the single long TTI HARQ feedback resource into multiple short TTI-specific HARQ feedback resources. Each short TTI is assigned its own dedicated feedback resource, allowing independent and timely feedback transmission. This segmentation resolves the contradiction by eliminating the latency issue while maintaining manageable resource configuration through systematic allocation rules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic HARQ feedback resource allocation where the feedback resource for each short TTI is determined based on the short TTI's position and timing within the long TTI structure. This dynamic allocation allows the system to adapt feedback resources to the specific scheduling requirements of each short TTI, reducing latency while keeping the overall resource management flexible and manageable.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If long TTI is used for data transmission, then resource allocation is simplified, but transmission flexibility and response to latency-sensitive services deteriorate

Engineering Contradiction:
Improveresource allocation complexityVSAvoidtransmission flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the long TTI into multiple short TTIs, each capable of independent scheduling and resource allocation. This segmentation allows the system to maintain the simplified overall resource framework of long TTI while enabling flexible, fine-grained resource allocation for individual short TTIs, thus resolving the contradiction between simplicity and flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by allowing only certain portions of the long TTI to be divided into short TTIs when latency-sensitive services are detected. The remaining portions can continue to use traditional long TTI allocation, thus gaining flexibility where needed while maintaining simplicity where not required, resolving the contradiction effectively.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If HARQ feedback resource is allocated at the tail of long TTI, then resource management is simplified, but transmission time and resource utilization deteriorate

Engineering Contradiction:
ImproveHARQ feedback resource management complexityVSAvoidresource utilization efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the single feedback resource at the tail of long TTI into multiple feedback resources distributed throughout the long TTI structure, with each short TTI having its own dedicated feedback resource. This segmentation enables earlier and more distributed feedback transmission, improving resource utilization while maintaining systematic resource management through clear allocation rules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by allocating HARQ feedback resources in advance for each short TTI based on predetermined rules, rather than waiting until the tail of the long TTI. This allows the system to prepare feedback resources beforehand, improving resource utilization efficiency while keeping resource management straightforward through pre-established allocation patterns.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3540995B1Method and apparatus for acquiring HARQ feedback information, and method and apparatus for transmitting HARQ feedback information
Publication Date: 2024.09.18 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3540995B1 patent drawingFigure 1-1~2
  • EP3540995B1 patent drawingFigure 3-1~5
  • EP3540995B1 patent drawingFigure 6~8

AI summary

The present disclosure provides a method and an apparatus for obtaining HARQ feedback and transmitting HARQ feedback. The method of obtaining HARQ feedback includes: short TTI scheduling information is configured into a first target long TTI according to service requirements; the short TTI scheduling information is sent to second equipment through the first target long TTI; one or more short TTIs in a second target long TTI is scheduled according to the short TTI scheduling information and the scheduled one or more short TTIs are sent to the second equipment; and HARQ feedback for each of the one or more short TTIs which is sequentially sent by the second equipment within the second target long TTI is received. The method provided in the present disclosure may effectively shorten the HARQ feedback latency of short TTIs and improve the flexibility of data transmission.