Workcell Concatenation Using WiFi-Based Wireless Networked

Control Systems

Tarek Refaat, Ramez Daoud, Mai Hassan,Hassanein Amer, Omneya Sultan

SEAD GROUPAmerican University

in Cairo

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SEAD GROUPAmerican University

in Cairo

Agenda

Previous WorkProposed ModelSimulated Scenarios OPNET Simulation ResultsConclusions

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SEAD GROUPAmerican University

in Cairo

Single-CellResults

◦ Noiseless: Correct Packet

Transmission & Reception

Max Delay of 2.5ms per link

◦ Effect of Noise: Correct Packet

Transmission & Reception

Max Delay of 14.8ms per link

Previous Work

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SEAD GROUPAmerican University

in Cairo

Goal

Concatenation of Identical Industrial Workcells Based

on WiFi without Modification

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SEAD GROUPAmerican University

in Cairo

Proposed Model

Reused Channel

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SEAD GROUPAmerican University

in Cairo

Simulation Stages

Finding minimum PRPT and minimum distance between the two cells

Finding the maximum total end-to-end delays per communication link at

minimum PRPT and minimum distance

Studying the effect of noise on the system

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SEAD GROUPAmerican University

in Cairo

ISM Band Interference

Alien NodeCh11

Ch1 Ch6

Ch11 Ch1

Alien NodeCh6

Ch1 Ch6

Ch11 Ch1

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SEAD GROUPAmerican University

in Cairo

OPNET Simulation Results

ScenarioMax FTP

(KB)

Max Delay

S→K (ms)

Max DelayK→A (ms)

1 Cell: No Noise 0 1.50 – 1.64 2.23 – 2.90

1 Cell: Noise 40 1.62 – 1.75 14.07 – 14.67

2 Cells: No Noise 0 0.66 – 0.71 2.99 – 3.53

2 Cells: Noise – Ch 6 40 1.06 – 1.13 11.99 – 12.65

2 Cells: Noise – Ch 11 40 1.01 – 1.08 11.97 – 12.57

Maximum FTP and Delays Per Scenario at 3m & -50dBm PRPT

9

SEAD GROUPAmerican University

in Cairo

OPNET Results

End-to-end delay from K to A in absence of noise

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SEAD GROUPAmerican University

in Cairo

OPNET Results

End-to-end delay from K to A in presence of noise

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SEAD GROUPAmerican University

in Cairo

ConclusionsConcatenating Industrial Workcells

using WiFi is Achievable.Minimum Inter-Cell Distance = 3m

with PRPT = -50dBmAll Delays are within Acceptable

Ranges with 95% Confidence AnalysisThe System Operates Successfully

with Zero Packet Loss in Presence of Noise due to Co-Channel Interference and ISM Band

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Thank You

SEAD GROUPAmerican University

in Cairo