Central Controller Selects Radio Heads for Probe Responses

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Solution Overview

Problem

In high-density Wi-Fi environments, Probe Requests and Responses consume significant airtime, often connecting clients to suboptimal access points, even when better options are available, leading to inefficient resource utilization and poor service quality.

Innovation Solution

A central controller manages multiple radio heads to select the best access point for Probe Responses based on metric calculations, ensuring clients connect to the most suitable radio head for improved signal quality and data rate, thereby reducing unnecessary Probe Responses and optimizing client connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Probe Requests are sent to identify available APs in high density environment, then client devices can discover access points, but airtime is significantly consumed and most responses do not indicate the best AP for service

Engineering Contradiction:

ImproveAP discovery capabilityVSAvoidairtime consumption

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by having APs continuously transmit beacon frames and maintain updated network information before clients need to connect. This allows the central controller to pre-calculate metric values and prepare optimal AP selections, so when Probe Requests arrive, the system can respond immediately with pre-determined best AP information rather than consuming airtime on extensive probe exchanges

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A central controller is introduced as an intermediary between clients and multiple APs. The central controller receives Probe Requests, consults pre-calculated metric values, and determines the best AP to respond. This intermediary consolidates the decision-making process, allowing clients to send fewer Probe Requests while still discovering the optimal AP, thereby reducing overall airtime consumption in high-density environments

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If client devices keep connection with original AP, then connection stability is maintained, but service quality deteriorates when better APs are available

Engineering Contradiction:

Improveconnection stabilityVSAvoidservice quality

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The system implements feedback mechanisms where the central controller continuously monitors metric values from multiple APs and client connection status. When metric values indicate a better AP is available, the system provides feedback to steer the client to switch APs. This feedback loop maintains connection stability by only triggering switches when genuinely better service is available, rather than causing unnecessary flapping

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system makes the AP selection dynamic by continuously updating metric values and allowing clients to switch APs based on current conditions. The central controller dynamically adjusts which AP should serve each client based on real-time metric calculations, enabling the network to adapt to changing conditions while maintaining stable connections through controlled, informed switching decisions

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If multiple APs respond to Probe Requests, then client devices can discover available options, but airtime is wasted on responses from suboptimal APs

Engineering Contradiction:

ImproveAP option discoveryVSAvoidairtime wastage

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system applies local quality by having different APs with different metric values serve different clients based on their specific characteristics and locations. The central controller calculates unique metric values for each AP-client pair, allowing the network to optimize locally for each connection rather than using a blanket response approach. This ensures clients receive responses from the locally optimal AP while minimizing unnecessary responses from suboptimal APs

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes parameters by using metric values as the deciding factor for AP selection. Instead of all APs responding equally to Probe Requests, the central controller uses calculated metric values to determine which AP should respond. This parameter-based selection changes the response behavior from uniform to differentiated, allowing clients to discover available options while preventing airtime wastage on responses from APs with poor metric values

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10455439B2Roaming and probe responses with remote radio heads

Publication Date: 2019.10.22 CISCO TECHNOLOGY INC

AI summary

The present disclosure discloses a central controller controlling multiple radio heads (RHs) in a network. The central controller generates network information for the radio heads based on a probe request transmitted from a network device and received by one or more of the radio heads. The central controller calculates a respective metric value for each of the radio heads based on the network information. The metric value indicates a capability of a radio head to serve the network device. The central controller selects a subset of radio heads from the multiple radio heads to send a probe response to the network device based on the metric values.