Wireless Access Point Load Balancing via Beacon Power Control

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Solution Overview

Problem

Current wireless communication systems face challenges in load balancing, particularly in WLANs, where clients may overload certain Access Points while adjacent points have lower loads, leading to inefficient resource management and high costs due to centralized control requirements, and clients struggle to switch to less loaded Access Points.

Innovation Solution

A load balancing method where clients transmit Probe Request messages to multiple Access Points, with overloaded Access Points responding at minimum power based on RSSI, allowing clients to preferentially connect to less loaded Access Points, and if no alternatives exist, connect to overloaded ones, using reduced power for reliable communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If centralized management is performed on all Access Points to achieve uniform resource management and load balancing, then system resource management is improved, but device complexity and cost increase due to requiring a complicated central control unit

Engineering Contradiction:
Improveresource management efficiencyVSAvoidcentral control unit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Each Access Point independently monitors its own service load and autonomously adjusts its beacon transmission power without requiring a central control unit. The APs self-manage their load balancing by comparing their load status with neighboring APs and adjusting transmission parameters accordingly, eliminating the need for complex centralized management infrastructure.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If clients select Access Points based on signal strength measurement, then connection establishment is simplified, but load balancing deteriorates as clients may concentrate on the same strong signal APs even when overloaded

Engineering Contradiction:
Improveconnection establishment easeVSAvoidload balancing performance
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system changes the parameter used for client selection from pure signal strength (RSSI) to a composite metric that includes both signal strength and load status. Access Points transmit their load information in beacon frames, allowing clients to evaluate both connection quality and AP availability, thereby achieving load balancing while maintaining ease of connection establishment.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If overloaded Access Points continue transmitting at normal power, then communication reliability is maintained, but load balancing deteriorates as they continue to attract new clients

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidload distribution efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Overloaded Access Points preemptively reduce their beacon transmission power before becoming completely saturated. This preliminary anti-action prevents new clients from selecting already overloaded APs by making their signals appear weaker in the client's signal strength comparison, thereby distributing load before the overload becomes critical while maintaining sufficient communication reliability for existing clients.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2524544B1A load balancing method for a wireless communication system
Publication Date: 2018.10.03 SIEMENS MOBILITY GMBH
  • EP2524544B1 patent drawingFigure 1~2
  • EP2524544B1 patent drawingFigure 3

AI summary

The present invention proposes a load balancing method for a wireless communication system, in which said system comprises a backbone network, more than one Access Point connected to said backbone network and more than one client, said method comprising the following steps: (1) the client transmits a Probe Request message to said more than one Access Point; (2) the Access Point monitors its load, if the Access Point is under an overload situation, it will transmit a Probe Response message to the client by the minimum transmitting power, and if the Access Point is under normal load situation, it will transmit a Probe Response message to said client by normal transmitting power; (3) the client preferentially chooses the Access Point under normal load situation to access based on the signal strength of the received Probe Respond message. The present method of invention provides the client with a priority of the Access Points, in which the Access Point under an overload situation has a lower priority.