Channel Switch Mechanism for Wireless Terminals

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Solution Overview

Problem

Existing channel switch mechanisms in wireless communication systems, particularly in unlicensed frequency bands and TVWS, face high probabilities of switch failure due to frequent channel changes, as they rely on beacon frames that are not suitable for rapid switching scenarios.

Innovation Solution

A method and apparatus for channel switch that involve sending a channel switch announcement instruction with a target channel position and time, followed by information exchange on both the original and target channels within a preset soft switch time interval, and then stopping transmission on the original channel after this interval ends, allowing for a smooth transition and reducing switch failure probabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beacon frames are transmitted multiple times to reduce switch failure probability, then reliability improves, but the long transmission period makes it unsuitable for frequent channel switching scenarios

Engineering Contradiction:
Improveswitch failure probabilityVSAvoidchannel switching speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the channel switching announcement process into multiple independent transmission opportunities. Instead of relying on a single long beacon frame transmission, the system transmits the channel switch announcement at multiple time points (t-T1, t-T2, ..., t-Tn) before the actual switch time. This segmentation allows users to receive the announcement through at least one successful transmission, reducing switch failure probability while enabling frequent channel switching.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If channel switching is performed frequently to adapt to changing channel conditions, then system adaptability improves, but the probability of switch failure increases due to insufficient notification time

Engineering Contradiction:
Improvechannel switching frequencyVSAvoidswitch failure probability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by transmitting the channel switch announcement well in advance of the actual channel switch. The system sends the announcement at multiple predetermined time points (t-T1, t-T2, ..., t-Tn) before the switch time t, giving users sufficient time to process and prepare for the switch. This preliminary notification approach enables frequent channel switching while maintaining high reliability by ensuring users receive the announcement before each switch.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If information is transmitted only on the target channel after switch announcement, then device complexity reduces, but information loss occurs during the transition period when users may not have fully switched channels

Engineering Contradiction:
Improvetransmission mechanism simplicityVSAvoidinformation delivery completeness
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent uses the original channel as an intermediary for information transmission during the transition period. After sending the channel switch announcement, the system continues to transmit information on both the original channel and the target channel within a preset time interval. This dual-channel transmission approach ensures that users who have not yet fully switched channels can still receive information on the original channel, while users who have switched can receive information on the target channel, thereby preventing information loss without significantly increasing system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2966904B1Channel switching method, device, and wireless terminal
Publication Date: 2018.09.05 HUAWEI TECH CO LTD
  • EP2966904B1 patent drawingFigure 1~2
  • EP2966904B1 patent drawingFigure 3~4
  • EP2966904B1 patent drawingFigure 5~7

AI summary

The present invention discloses a method, an apparatus and a wireless terminal for channel switch, and the method includes: sending information on the target channel and a first channel within the preset channel soft switch time interval after a channel switch announcement instruction is sent on the first channel when the first channel needs to be switched, and stopping sending information on the first channel if the preset channel soft switch time interval ends. By means of above method, the probability of switch failure for the user may be reduced in a scenario with frequent channel switch.