WLAN Controller Automatic Channel Selection Using Graph Coloring
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Solution Overview
Problem
In large-scale enterprise WLAN deployments, channel interference and spectral inefficiency due to co-channel and adjacent channel interference hinder effective radio coverage and bandwidth availability, especially in dynamic radio environments.
Innovation Solution
The implementation of an automatic channel selection system using color graphs (GCA) in WLAN controllers, where access points are assigned non-interfering channels based on scan results and RSSI measurements to prevent interference, ensuring optimal channel allocation even in high-density deployments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If access points are placed with overlapping radio coverage area to ensure effective radio coverage, then radio coverage is improved, but spectral efficiency deteriorates due to co-channel and adjacent channel interference
Solution Approach 1:
The patent applies local quality by assigning different channel colors to different spatial locations of access points. The GCA algorithm analyzes the spatial topology and assigns channels based on local interference relationships, ensuring that access points in overlapping coverage areas use different channels while access points in non-interfering locations can share channels, thus optimizing both coverage and spectral efficiency locally
Solution Approach 2:
The patent segments the wireless network into multiple channel groups (colors) and assigns them to different access points based on spatial relationships. This segmentation allows the network to divide the limited spectral resources into multiple non-interfering segments, enabling simultaneous transmissions without interference and improving overall spectral efficiency
2Quantity of substance
If the number of access points increases to provide better coverage, then radio coverage is improved, but channel interference worsens due to limited non-interfering channels
Solution Approach 1:
The patent introduces a new dimension by using graph coloring theory to model the interference relationships between access points. Instead of treating channel assignment as a one-dimensional problem with limited channels, the GCA algorithm creates a multi-dimensional solution space where channels are assigned based on the topological relationships in the access point network, enabling scalable channel assignment for any number of access points
Solution Approach 2:
The patent changes the parameter of channel assignment from static to dynamic by implementing continuous monitoring of channel conditions and periodic re-execution of the GCA algorithm. This allows the system to adapt to changing network conditions, adding or removing access points, and maintaining optimal channel assignments as the network evolves
3Loss of energy
If manual channel configuration is used to reduce interference, then spectral efficiency is improved, but device complexity and ease of operation worsen
Solution Approach 1:
The patent implements self-service by enabling the wireless network to automatically perform channel assignment and optimization without manual intervention. The GCA algorithm is executed automatically by the controller, which collects network topology information, determines interference relationships, assigns optimal channels, and configures access points autonomously. This eliminates the need for manual channel configuration while achieving optimal spectral efficiency
Solution Approach 2:
The patent incorporates feedback mechanisms where the controller continuously monitors channel conditions, interference levels, and network performance. Based on this feedback, the system periodically re-executes the GCA algorithm to re-optimize channel assignments, ensuring that the network maintains optimal spectral efficiency as conditions change
4Productivity
If channels are shared among access points to improve resource utilization, then productivity is improved, but reliability deteriorates due to increased interference
Solution Approach 1:
The patent applies local quality by allowing channel sharing only between access points that are determined to be non-interfering based on their spatial relationships and transmission characteristics. The GCA algorithm assigns the same channel color to access points that do not have overlapping coverage areas or significant interference relationships, enabling resource sharing while maintaining connection stability
Solution Approach 2:
The patent implements dynamics by making channel assignments adaptable to changing network conditions. The system continuously monitors interference levels and can dynamically reassign channels when conditions change, allowing access points to share channels when conditions permit while switching to dedicated channels when interference is detected, thus balancing resource utilization and connection stability
Data Source
AI summary
Wi-Fi channels are automatically selected in a WLAN controller based deployment. Scan results received from each of the plurality of access points comprise a list of neighboring access points from the plurality of access points relative to each access point. Responsive to a number of the plurality of access points exceeding a number of non-interfering channels, assigning each of the plurality of access points to a non-interfering channel with sharing of at least one of the non-interfering channels, using a GCA (Graph Coloring Algorithm) in which each color assignment corresponds to a non-interfering channel assignment in order to prevent neighboring access points from sharing a non-interfering channel. Lowest RSSI measurements collected by access points can also be a factor in channel selection.