NR-U TXOP Reservation Structure for Hidden Node Interference

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Solution Overview

Problem

Existing wireless communication technologies face challenges in accurately capturing interference in shared spectrum, leading to hidden node interference and significant overhead in listen-before-talk procedures, which affects spectrum utilization and sharing efficiency.

Innovation Solution

Implementing flexible scheduling techniques that allow communication to occur before and after receiving channel reservation responses, reducing idle time in the spectrum by utilizing gap periods for transmissions, and selecting UEs with lower modulation orders to improve spectrum utilization and sharing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transmit-based LBT procedure is used to reserve TXOP, then channel collision is avoided, but hidden node interference occurs and reservation overhead is significant

Engineering Contradiction:
Improvecollision avoidanceVSAvoidhidden node interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The receiving node performs preliminary channel sensing before transmitting the reservation response signal. This preliminary action allows the receiving node to detect potential hidden node interference and make informed decisions about whether to proceed with the reservation, thereby avoiding hidden node interference while maintaining reliable collision avoidance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The receiving node provides feedback about channel conditions and interference detection to the transmitting node through the reservation response signal. This feedback mechanism enables the transmitting node to adjust its transmission strategy and avoid hidden node interference, improving overall system reliability.

Inventive Principle:
Principle #23Feedback

2Object-generated harmful factors

If receiving node processes reservation and prepares response, then hidden node interference is reduced, but reservation overhead becomes significant

Engineering Contradiction:
Improvehidden node interferenceVSAvoidreservation overhead
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent implements dynamic processing where the receiving node can quickly sense the channel and respond based on real-time conditions. The processing time and response duration are dynamically adjusted according to channel conditions and interference levels, reducing unnecessary overhead while maintaining effective hidden node interference prevention.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes operational parameters such as response time, processing duration, and transmission power based on detected interference levels and channel conditions. By adjusting these parameters dynamically, the system reduces reservation overhead when interference is low while maintaining protective measures when interference is detected.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If flexible scheduling is implemented allowing communication before response, then spectrum utilization improves, but scheduling complexity increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidscheduling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The transmitting node performs preliminary scheduling decisions and transmits data signals before receiving the reservation response. This preliminary action allows the system to utilize spectrum more efficiently by not waiting for the response before starting communication, while the scheduling complexity is managed through pre-configured protocols and constraints.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The scheduling system dynamically adapts to received responses while maintaining flexible communication schedules. The system can switch between different scheduling modes based on channel conditions and response status, improving spectrum utilization without creating unmanageable complexity through standardized dynamic adjustment rules.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3815455B1Transmission opportunity (TXOP) structure for new radio-unlicensed (NR-u) and new radio-synchronized sharing (NR-ss)
Publication Date: 2025.11.26 QUALCOMM INC
  • EP3815455B1 patent drawingFigure 1
  • EP3815455B1 patent drawingFigure 2
  • EP3815455B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to communicating in a shared communication medium with flexible scheduling are provided. A first wireless communication device communicates, with a second wireless communication device during a reservation period, a channel reservation request for a first transmission opportunity (TXOP) in a spectrum. The first wireless communication device communicates, with the second wireless communication device during a response period in response to the channel reservation request, a channel reservation response. The first wireless communication device communicates, with a third wireless communication device during a first time period between the reservation period and the response period, a first communication signal.