Adaptive CCA and TX Power Adjustment for Dense Wireless Networks
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Solution Overview
Problem
In dense wireless network deployments, existing Clear Channel Assessment (CCA) methods lead to interference, congestion, and low throughput due to excessive deferral and increased power consumption, while attempting to increase spatial reuse and fairness between different stations and legacy devices.
Innovation Solution
A method involving adaptive Clear Channel Assessment (CCA) and transmit power control (TPC) is implemented, where wireless stations detect spatial reuse information to adjust their TX spectral density and CCA levels, allowing for spatial reuse without causing collisions and maintaining fairness and power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If baseline CCA level is used in dense deployment, then legacy compatibility is maintained, but network throughput decreases due to excessive deferral
Solution Approach 1:
The patent implements dynamic CCA level adjustment where stations adapt their CCA thresholds based on received signal strength from other BSS stations. Instead of using a fixed baseline CCA level, each station calculates an adaptive CCA level by comparing received signals against a threshold, allowing the system to dynamically optimize throughput while maintaining legacy compatibility through selective application of the adaptive mechanism.
Solution Approach 2:
The patent changes the CCA level parameter from a fixed baseline value to an adaptive value calculated based on received signal strength. By modifying the CCA threshold parameter dynamically according to environmental conditions and interference levels, the system resolves the contradiction between maintaining legacy compatibility and improving network throughput in dense deployments.
2Productivity
If CCA level is increased to reduce deferral, then spatial reuse improves, but interference and collisions increase
Solution Approach 1:
The patent applies different CCA levels locally to different stations based on their specific reception conditions. Each station calculates its own adaptive CCA level based on the received signal strength from specific other BSS stations, rather than uniformly increasing CCA levels across the entire network. This localized adaptation allows spatial reuse improvement while controlling interference through individualized threshold adjustment.
Solution Approach 2:
The patent implements a feedback mechanism where stations continuously monitor received signal strength from other BSS stations and adjust their CCA levels accordingly. This closed-loop feedback allows the system to optimize spatial reuse by increasing CCA levels when interference is low, while automatically reducing CCA levels when interference or collision risk increases, thus resolving the contradiction between spatial reuse and interference control.
3Use of energy by moving object
If transmit power is reduced to decrease interference, then power consumption decreases, but channel access likelihood decreases
Solution Approach 1:
The patent performs preliminary action by having stations calculate and set appropriate CCA levels before attempting channel access. By pre-adjusting the CCA threshold based on received signal strength from other BSS stations, stations can more accurately determine when the channel is suitable for access, improving channel access likelihood without requiring increased transmit power, thus addressing the contradiction between power consumption and channel access.
4Productivity
If adaptive CCA and TPC are implemented, then network throughput and spatial reuse improve, but device complexity increases
Solution Approach 1:
The patent implements self-service by having each station independently calculate and adjust its own CCA level and transmit power based on locally observed received signal strength. Rather than requiring complex centralized coordination or sophisticated algorithms, each station autonomously adapts its parameters using simple comparisons and calculations, thereby improving network throughput while minimizing the increase in device complexity.
Data Source
AI summary
A method of spatial re-use with TPC and adaptive CCA is proposed. A spatial re-use station detects spatial re-use information associated with other peer OBSS stations. The spatial re-use information comprises a TX spectral density (power/Hz) and received signal or interference information of each inter-BSS peer station. The spatial re-use STA determines a TX spectral density based on the detected spatial re-use information. The spatial re-use STA then contends the medium for spatial re-use transmission opportunity (TXOP) with an intra-BSS peer station. Finally, the spatial re-use STA starts spatial re-use frame exchange with the intra-BSS peer station using the determined TX spectral density. By adjusting the TX spectral density, the spatial re-use STA adapts its CCA level to spatially reuse the medium without causing collision and interference to OBSS stations and thus increases network throughput.