Dynamic TDD in Shared Spectrum via Priority-Based TXOP Partitioning

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in spectrum sharing due to high medium-sensing signaling overheads, particularly when using dynamic time-division duplexing (TDD) and self-contained subframes, which can lead to increased latency and interference between network operating entities.

Innovation Solution

Implementing a priority-based coordinated access scheme that partitions the shared spectrum into transmission opportunities (TXOPs), where each TXOP includes a common sensing period for reservation requests and responses, allowing for dynamic TDD and self-contained subframes to protect both data and control information communications, enabling efficient resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If medium-sensing procedures (e.g., listen-before-talk) are used to avoid interference in shared spectrum, then interference between different devices or network operating entities is reduced, but signaling overhead increases and latency is increased

Engineering Contradiction:
ImproveinterferenceVSAvoidlatency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing medium sensing and reservation procedures in advance before actual data transmission. The LBT procedure is executed in a first time period, and transmission opportunities are reserved beforehand, allowing the actual data transmission to occur in subsequent time periods without repeated sensing overhead, thus reducing latency while maintaining interference avoidance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the transmission process into distinct time periods: a first time period for medium sensing and reservation requests, and subsequent time periods for actual data transmission. This segmentation separates the overhead-generating sensing operations from the data-carrying transmission operations, reducing the latency impact of medium-sensing procedures on overall communication efficiency

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If medium-sensing procedures are used to avoid interference in shared spectrum, then interference between different devices or network operating entities is reduced, but signaling overhead increases

Engineering Contradiction:
ImproveinterferenceVSAvoidsignaling overhead
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent performs medium sensing and transmission opportunity reservation in advance during a first time period before actual data transmission. By completing the sensing and reservation procedures beforehand, the system reduces the amount of repeated signaling overhead that would otherwise be required during each data transmission interval, thus reducing overall signaling overhead while maintaining interference avoidance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the communication process into separate time periods: initial medium sensing and reservation phase, followed by data transmission phase. This segmentation concentrates the signaling overhead into a dedicated preliminary phase, separating it from the data-carrying phase and thereby reducing the overall signaling overhead burden on the shared spectrum

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If dynamic TDD is implemented to allow link priority changes from default link direction, then adaptability of spectrum usage is improved, but coordination complexity between network operating entities increases

Engineering Contradiction:
Improvelink priority flexibilityVSAvoidcoordination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by establishing default link directions and priority configurations in advance through pre-configuration or initial agreement between network operating entities. These default settings provide a baseline coordination framework that reduces the complexity of real-time dynamic TDD adjustments, while still allowing flexibility when needed through reserved transmission opportunities

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic TDD by allowing network operating entities to change link priorities and switch between default and dynamic configurations based on traffic conditions. The system transitions from static default link directions to dynamic adaptive configurations, enabling flexibility in link priority changes while maintaining coordination through the reserved transmission opportunity framework

Inventive Principle:
Principle #15Dynamics

4Productivity

If self-contained subframes are used to include DL control information, DL or UL data, and UL control information, then communication efficiency within a transmission opportunity is improved, but the requirement for protecting control information communication increases complexity

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidprotection mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges DL control information, DL or UL data, and UL control information into a single self-contained subframe structure. By combining these elements into one integrated transmission unit, the system improves communication efficiency within each transmission opportunity while simplifying the protection mechanism, as the entire self-contained subframe can be protected as a unified entity rather than requiring separate protection for each component

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3571858B1Dynamic time-division duplexing (TDD) in new radio-spectrum sharing (NR-ss) and self-contained subframe structure
Publication Date: 2021.04.14 QUALCOMM INC
  • EP3571858B1 patent drawingFigure 1
  • EP3571858B1 patent drawingFigure 2
  • EP3571858B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to dynamic time-division duplexing (TDD) and self-contained subframe-based communications in a shared spectrum are provided. A first wireless communication device communicates a control information communication protection request over a shared spectrum. The shared spectrum is shared by a plurality of network operating entities based on priorities. The first wireless communication device is associated with a first network operating entity of the plurality of network operating entities. The first wireless communication device communicates, with a second wireless communication device associated with the first network operating entity, control information in a first link direction during a transmission opportunity (TXOP) in the shared spectrum. The first wireless communication device communicates, with the second wireless communication device, data in a second link direction during the TXOP.