AFC-Assisted Wi-Fi Puncturing for Incumbent-Aware LPI Channel Access
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Solution Overview
Problem
Government regulators require low power indoor (LPI) access points to perform contention-based channel access on sub-channels containing incumbents, even if interference is not detected, limiting the use of puncturing techniques that could cause one-sided interference.
Innovation Solution
Implementing AFC-enabled access points that receive maximum permissible power levels from an AFC operator, allowing them to identify channels of concern and puncture sub-channels in LPI mode only when the incumbent's power is below a threshold, thereby avoiding interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LPI AP performs contention-based channel access on sub-channels containing incumbents, then regulatory compliance is achieved, but spectrum utilization efficiency deteriorates
Solution Approach 1:
The patent segments the channel access process into two independent parts: (1) AFC-based clear channel assessment for sub-channels containing incumbents, and (2) contention-based access for other sub-channels. This allows the LPI AP to use AFC information to determine whether to puncture incumbent channels, enabling selective access that maintains compliance while improving overall spectrum utilization efficiency.
2Productivity
If LPI AP punctures sub-channels containing incumbents, then bandwidth is increased, but interference to incumbents may occur
Solution Approach 1:
The patent implements a feedback mechanism where the LPI AP receives AFC information about incumbent locations and power levels, uses this feedback to determine whether to puncture specific sub-channels, and adjusts its transmission strategy accordingly. This closed-loop approach enables the AP to increase bandwidth through selective puncturing while preventing interference to incumbents through continuous monitoring and adaptation.
3Object-affected harmful factors
If LPI AP performs CCA on all sub-channels including punctured ones, then interference protection is improved, but channel access complexity increases
Solution Approach 1:
The patent extracts the CCA requirement from all sub-channels and applies it selectively only to sub-channels containing incumbents. By removing the CCA requirement from punctured sub-channels (where interference protection is not needed) while maintaining it for other sub-channels, the system achieves adequate interference protection with reduced operational complexity.
Data Source
AI summary
An AP is disclosed that identifies which channels (or sub-channels) to puncture when performing low power indoor (LPI) mode using information learned from automated frequency coordination (AFC). An AP that is AFC enabled—i.e., communicates with an AFC operator—can receive AFC information regarding incumbents at the AP's location. The AP can compare the power assignments for the incumbents provided in the AFC response to a threshold to determine whether to perform puncturing on the channel containing the incumbent. That is, the AP can use the threshold to determine whether puncturing the channel containing the incumbent when operating in the LPI mode is likely to negatively impact the incumbent.