Receiver-Assisted Channel Access for Directional LBT Reliability

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Solution Overview

Problem

In wireless communications systems using shared radio frequency spectrum, existing listen-before-talk (LBT) procedures may fail to detect channel occupancy reliably due to directional beamforming, especially at high frequencies like 60 GHz, leading to unreliable channel access for receiving devices.

Innovation Solution

Implement receiver-assisted channel access where the receiving device provides an interference measurement report to the transmitting device, using modified channel state information reference signals (CSI-RS) to measure channel occupancy across the entire bandwidth, allowing for fast and efficient channel availability assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the transmitting device performs LBT procedure using directional beamforming at high frequencies, then the transmission directionality is improved, but the channel occupancy detection reliability deteriorates

Engineering Contradiction:

Improvetransmission directionalityVSAvoidchannel occupancy detection reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent introduces the receiving device as an intermediary that performs channel occupancy detection and reports findings to the transmitting device. This mediator approach allows the system to maintain directional beamforming benefits while overcoming the transmitting device's inability to reliably detect interferers in directional modes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of having the transmitting device perform channel occupancy detection (the conventional approach), the patent inverts the role by having the receiving device perform the detection and report to the transmitter. This reversal enables reliable channel access determination despite the transmitting device's directional beamforming limitations.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If the receiving device performs interference measurement and reporting, then the channel access reliability is improved, but the processing overhead is increased

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidprocessing overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent leverages the receiving device's existing channel measurement capabilities (originally designed for channel quality assessment) and repurposes them for channel occupancy detection. This multi-functionality approach allows the receiver to perform interference measurement without requiring entirely new processing infrastructure, thereby limiting the increase in processing overhead.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The receiving device utilizes its own received signals to perform interference measurement and channel occupancy detection. By using signals already present at the receiver (downlink reference signals or data signals), the system avoids additional measurement overhead that would result from separate dedicated measurement signals.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If the receiving device measures channel occupancy across the entire bandwidth, then the measurement accuracy is improved, but the measurement time is increased

Engineering Contradiction:

Improvechannel occupancy measurement accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs partial bandwidth measurement strategies where the receiving device measures channel occupancy across selected portions of the entire bandwidth rather than uniformly across all frequencies. This partial action approach maintains sufficient measurement accuracy for channel access determination while significantly reducing the total measurement time compared to measuring the complete bandwidth.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12477366B2Techniques for interference measurement reporting for receiver-assisted channel access

Publication Date: 2025.11.18 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described for receiver-assisted channel access in shared radio frequency spectrum. A receiver, such as a user equipment (UE) may transmit a measurement report to a transmitter, such as an access network entity, that indicates channel occupancy as measured at the receiver. In some cases, the receiver may identify resources for signal measurement and reporting that are configured by the transmitter, and provide an interference measurement report based on the signal measurements. The interference measurement report may indicate whether a channel is occupied, or an occupancy level of the channel. Resources may be configured for multiple beams, with the interference measurement report including interference measurements for the multiple beams. Further, the signal resources may provide resources for a listen-before-talk (LBT) procedure, through signal resource sets that span multiple slots.