Non-Compliant Wireless Terminal Channel Search Mechanism

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Solution Overview

Problem

In wireless networks using the IEEE802.11 standard, non-compliant terminals cannot follow channel switches initiated by compliant base stations, leading to communication failures when radio wave conditions deteriorate.

Innovation Solution

A wireless device compliant with the IEEE802.11 standard but not IEEE802.11h sends probe requests to confirm the base station's presence and switches channels by searching other channels when no response is received, ensuring continued data communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the base station switches channels automatically according to IEEE802.11h standard, then the reliability of data communication is improved, but the non-compliant terminal cannot follow the channel switch leading to communication failure

Engineering Contradiction:

Improvedata communication reliabilityVSAvoidcompatibility with non-compliant terminals

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The terminal transmits probe requests at regular intervals and checks for probe responses from the base station. This feedback mechanism allows the terminal to detect channel changes initiated by the base station and automatically switch to the new channel, maintaining communication continuity despite IEEE802.11h non-compliance

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The terminal independently performs channel switching by transmitting probe requests and detecting base station responses, without requiring IEEE802.11h dynamic frequency switching functionality or base station coordination. The terminal serves itself to maintain communication reliability

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If the terminal continuously transmits probe requests to detect channel changes, then the adaptability to channel switches is improved, but the energy consumption increases

Engineering Contradiction:

Improvechannel switching detection capabilityVSAvoidterminal energy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The terminal transmits probe requests at predetermined time intervals rather than continuously or constantly. This periodic transmission approach enables the terminal to detect channel changes while controlling energy consumption by activating the transmission function only at specific intervals

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The terminal performs probe request transmission only when necessary for channel detection, rather than maintaining constant monitoring. This partial action approach balances the need for channel switch detection with energy conservation by limiting transmission activities

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7352716B2Wireless network having IEEE802.11h-incompliant terminal wireless device communicating with IEEE802.11h-compliant base wireless device

Publication Date: 2008.04.01 SOCIONEXT INC

AI summary

In a wireless network structure which includes a wireless LAN device having a base station function (host device) which is compliant with IEEE802.11h and at least one wireless LAN device having a terminal function (slave device) which is not compliant with IEEE802.11h, the incompliant terminal transmits a probe request to the base station for confirming the presence of the base station. When the base station has dynamically switched its channel (frequency), a probe response is not returned from the base station to the terminal. Thus, the incompliant terminal transmits a probe request through a different channel in order to confirm the presence of the base station. The incompliant terminal repeats the above channel search process till the base station is found.