Narrow Beam Channel Access via Spatial Stream Thresholds

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Solution Overview

Problem

Wireless communication systems in shared radio frequency spectrum bands face inefficiencies due to the need for channel access procedures like listen-before-talk (LBT) and long-term (LT) sensing, which result in latency and interference, especially when using directional beams for communication.

Innovation Solution

The implementation of narrow beam-based channel access methods that determine the relative narrowness of a directional beam based on spatial streams and effective isotropic radiated power (EIRP) thresholds, allowing devices to communicate without performing traditional channel access procedures, thereby reducing interference and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional channel access procedures (LBT, LT sensing) are performed in shared radio frequency spectrum bands, then interference between devices is mitigated, but communication latency increases and system efficiency decreases

Engineering Contradiction:

ImproveinterferenceVSAvoidlatency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent segments the shared radio frequency spectrum access into two distinct pathways: (1) narrow beam transmissions that meet specific criteria can proceed without channel access procedures, and (2) other transmissions must perform LBT/LT sensing. This segmentation allows low-interference narrow beams to bypass latency-inducing procedures while maintaining interference mitigation for other transmissions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different channel access requirements to different spatial regions and beam types. Narrow beams meeting specific criteria (based on beamwidth, power spectral density, and spatial stream count) are granted local exemption from channel access procedures, while other transmissions retain traditional requirements. This local quality differentiation resolves the contradiction by allowing efficient access where interference is naturally low.

Inventive Principle:

Principle #3Local quality

2Productivity

If narrow beam transmissions are allowed without channel access procedures, then communication efficiency improves and latency reduces, but interference control becomes more challenging

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent establishes specific parameter thresholds for narrow beam transmissions to qualify for exempted channel access: maximum beamwidth limits, minimum spatial stream counts, and power spectral density constraints. By changing and controlling these parameters, the system enables efficient narrow beam communication while maintaining interference control through quantitative criteria.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical channel access procedure (LBT/LT sensing) with a criterion-based exemption system for narrow beams. Instead of requiring all transmissions to perform time-consuming sensing procedures, the system substitutes a pre-defined criterion evaluation that determines whether a transmission qualifies for direct access, thereby improving efficiency while maintaining interference control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If channel access procedures are performed for all transmissions in shared spectrum, then fair spectrum access is ensured, but system throughput and spectral usage efficiency decrease

Engineering Contradiction:

Improvefair spectrum accessVSAvoidsystem throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments spectrum access into exempted narrow beam transmissions and traditional channel-access-required transmissions. This segmentation maintains fairness for the majority of transmissions while allowing high-efficiency narrow beams to bypass procedures, thereby preserving system throughput without completely sacrificing fair access principles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies channel access procedures partially - only to transmissions that do not meet narrow beam criteria. By applying the procedure selectively rather than universally, the system maintains fairness where needed while avoiding unnecessary throughput reduction for transmissions that can safely proceed without sensing.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12255720B2Directional channel access using a narrow beam with multiple spatial streams

Publication Date: 2025.03.18 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communication are described. Aspects of the disclosure describe narrow beam-based channel access that enables a device to communicate in a shared radio frequency spectrum band without performing channel access procedures. Specifically, aspects of the disclosure describe techniques for defining one or more directional beams as a narrow beam, where the relative narrowness of the beam may be determined in the context of interference (e.g., as opposed to being defined from a geometric perspective). For example, a particular beam may be determined to be a narrow beam, and therefore associated with communications in shared radio frequency spectrum bands without channel access procedures, based on one or more metrics and a number of spatial streams associated with the beam. A device may use such narrow beams for communications without channel access procedures in shared radio frequency spectrum bands.