Directional Channel Sensing for Beamformed Transmissions
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Solution Overview
Problem
In high-frequency bands, directional Listen Before Talk (LBT) channel access techniques face challenges in accurately sensing ongoing transmissions due to the limitations of quasi-omni sensing beams, which can lead to over-protection and interference issues, especially when multiple transmission beams are employed in beamformed communications.
Innovation Solution
The approach involves dividing transmission beams into groups and determining specific sensing beams for each group, using a scale factor to ensure sufficient sensing gain, and performing Clear Channel Assessment (CCA) with energy detection thresholds adjusted accordingly, allowing for directional sensing that aligns with intended transmission directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quasi-omni sensing beams are used for channel access, then channel sensing coverage is improved, but false positives and interference increase due to over-protection
Solution Approach 1:
The patent segments the sensing beam pattern into multiple directional beams corresponding to different transmission beam groups. Instead of using a single quasi-omni sensing beam, the system divides the 360-degree sensing space into multiple directional sectors, each aligned with specific transmission beam directions. This segmentation allows the system to sense only in directions where transmissions are actually performed, eliminating false positives from directions where no transmissions occur.
Solution Approach 2:
The patent applies local quality by making the sensing beam pattern non-uniform - different directions have different sensing sensitivities based on whether transmissions are performed in those directions. The sensing gain is concentrated in directions aligned with transmission beams, while directions without transmissions have reduced or zero sensing sensitivity. This creates a localized sensing quality that matches the actual transmission behavior, reducing unnecessary over-protection.
2Object-affected harmful factors
If directional sensing beams are used to reduce false positives, then interference is reduced, but sensing reliability may deteriorate if beams are not properly aligned
Solution Approach 1:
The patent performs preliminary action by pre-calculating and pre-aligning the directional sensing beams with the transmission beam directions before actual channel access. The sensing beam directions are determined in advance based on the configured transmission beam patterns, ensuring that when sensing occurs, the beams are already properly oriented to detect transmissions in the correct directions. This preliminary alignment configuration ensures sensing reliability without requiring real-time adjustment.
3Productivity
If multiple transmission beams are used in beamformed communications, then spectrum utilization is improved, but channel access complexity increases due to multiple sensing requirements
Solution Approach 1:
The patent merges the channel access procedures for multiple transmission beams into a unified process. Instead of requiring separate CCA procedures for each beam, the system combines them into a single sensing operation where multiple directional sensing beams are activated simultaneously or in sequence to cover all transmission beam directions. This merging approach maintains the benefits of multiple beams for spectrum utilization while simplifying the channel access procedure to a single integrated sensing action.
Data Source
AI summary
According to various embodiments, a wireless communication device divides a plurality of transmission beams into one or more groups of transmission beams including at least a first group of transmission beams. The wireless communication device determines a first sensing beam requirement for the first group of transmission beams. The wireless communication device determines a first sensing beam and a first scale factor so that the first sensing beam satisfies the first sensing beam requirement scaled by the first scale factor. The first sensing beam is selected from a set of candidate sensing beams. The wireless communication device performs a first Clear Channel Assessment (CCA) using the first sensing beam and a first energy detection threshold (EDT), the first EDT determined in accordance with the first scale factor.