Wireless Environment Evaluation for Exposed Station Detection

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Solution Overview

Problem

Current wireless communication systems using CSMA/CA method struggle to accurately determine the extent of exposed situations in reception and transmission due to hidden wireless stations, leading to decreased reception rates and transmission opportunities, which affects throughput characteristics.

Innovation Solution

A method to evaluate the wireless environment by analyzing transmission and reception history, estimating the number of stations in standby, and calculating specific rates to determine the degree of exposed situations in reception and transmission, allowing for improved access control and throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If random access control using CSMA/CA method is performed, then wireless communication can be established among multiple stations, but transmission timing overlap occurs causing decreased reception rate

Engineering Contradiction:
Improvewireless communication capabilityVSAvoidreception rate
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention performs preliminary actions by acquiring transmission and reception histories before evaluating the wireless environment. The system calculates expected reception rates based on historical data and compares them with actual reception rates to identify exposed situations before they significantly impact communication performance. This allows proactive adjustment of communication parameters.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention implements feedback mechanisms by continuously monitoring actual reception rates and comparing them with expected reception rates derived from transmission histories. When discrepancies indicate exposed situations, the system feeds this information back to adjust access control parameters, creating a closed-loop control system that optimizes reception performance.

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If multiple wireless stations perform random access control, then network coverage is improved, but transmission opportunity acquisition rate decreases due to exposure from hidden stations

Engineering Contradiction:
Improvenetwork coverageVSAvoidtransmission opportunity acquisition rate
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The system performs preliminary analysis by acquiring transmission histories from multiple stations before evaluating the wireless environment. It calculates expected transmission opportunity acquisition rates based on historical patterns and identifies exposed situations proactively, allowing stations to adjust their access control behavior before performance degradation occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention establishes feedback loops that monitor actual transmission opportunity acquisition rates and compare them with expected rates derived from reception histories. When exposed situations are detected through this feedback mechanism, the system adjusts access control parameters to optimize transmission opportunities while maintaining expanded network coverage.

Inventive Principle:
Principle #23Feedback

3Reliability

If RTS/CTS flow control is used to solve hidden station problem, then packet collision is reduced, but additional signaling overhead increases transmission time

Engineering Contradiction:
Improvepacket collision reductionVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention applies partial action by selectively evaluating whether RTS/CTS flow control is necessary. Instead of universally applying RTS/CTS to all transmissions, the system uses reception and transmission histories to identify specific cases where hidden station problems are likely to occur. RTS/CTS is then applied only to those specific cases, reducing unnecessary signaling overhead while still protecting against packet collisions when needed.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3422759B1Wireless environment evaluation method and wireless communication system
Publication Date: 2021.06.09 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3422759B1 patent drawingFigure 1
  • EP3422759B1 patent drawingFigure 2
  • EP3422759B1 patent drawingFigure 3

AI summary

Provided is a wireless environment evaluation method including a step 1 acquiring a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations and acquiring or estimating a number of wireless stations in transmission standby, based on the transmission and reception history; a step 2 calculating a normal reception rate S in a congesting situation in reception according to the number of wireless stations in transmission standby; a step 3 acquiring a normal reception rate S' of the wireless signals per a fixed channel use time from the transmission and reception history in the prescribed wireless station; and a step 4 determining a degree of the exposed situation in reception according to a ratio of the normal reception rate S' to the normal reception rate S.