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BER measurement--- Screen OFDMTrang Nguyen

June 2018

Experiment setup 1 – Straight LoS

8cm×8cm (16×16 A-QL) Tx

• Distance: 1.5m• Distance: 3m• Distance: 4.5m

84×84 (Screen OFDM) Tx

Same 5-pixel/ Tx cell

For a fair evaluation!

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Experiment result 1

1.5m –0 perspective degree

3m --0 perspective degree

4.5m --0 perspective degree

Bits received 1495368 1578960 1671840

error 1 49317 2540 8486

error 2 359 399 280

error 3 - - -

Experiment results 1

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Experiment results 1

Experiment setup 2 – 30-degree Perspective LoS

• Distance: 1.5m• Distance: 3m• Distance: 4.5m

8cm×8cm (16×16 A-QL) Tx

84×84 (Screen OFDM) Tx

Same 5-pixel/ Tx cell

For a fair evaluation!

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Experiment result 2

1.5m --30 degree 3m --30 degree 4.5m --30 degree

Bits received 873072 1356048 705888

error 1 253517 56267 42245

error 2 71466 875 3473

error 3 - - -

Experiment results 2

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Experiment results 2

Experiment setup 3 – 60-degree Perspective LoS

• Distance: 1.5m• Distance: 3m• Distance: 4.5m

8cm×8cm (16×16 A-QL) Tx

84×84 (Screen OFDM) Tx

Same 5-pixel/ Tx cell

For a fair evaluation!

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Experiment result 3

1.5m --60 degree 3m --60 degree 4.5m --60 degree

Bits received 668736 566568 752328

error 1 151082 144264 139067

error 2 36871 35378 24219

error 3 - - -

Experiment results 3

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Experiment results 3

BER measurement scenario 1

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1.5m distance

1.5m distance

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3m distance

3m distance

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4.5m distance

4.5m distance

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BER measurement scenario 230-degree Perspective

1.5m distance

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1.5m distance

3m distance

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3m distance

4.5m distance

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4.5m distance

BER measurement scenario 360-degree Perspective

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1.5m distance

1.5m distance

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3m distance

3m distance

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4.5m distance

4.5m distance

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Performance Summary

0-degree 30-degree

60-degree

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Performance Comparison

Comparison –Scenario 1

A-QL Screen OFDM

Screen OFDM brings much better BER performance when the distance increasing. Screen OFDM performance is more stable vs distance.

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Comparison –Scenario 2

A-QL Screen OFDM

Screen OFDM brings better BER performance when the distance increasing. In contrast, at short distance (1.5m), A-QL can take its advantage. The reason is related to the Cosine-forth law.

Comparison –Scenario 3

A-QL Screen OFDM

Screen OFDM is more stable with the perspective distortion such as 60-degree viewing.Also, it can perform better at far distance.

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Conclusion

BER of Screen-OFDM has been measured. The impacts of distance and viewing angle to BER are

tested.

▪ Screen-OFDM significantly outperformed A-QL in terms of BER performance for a greater

communication distance and wider perspective view.

▪ For BER 10-5 requirement, Screen-OFDM works reliably as far as 4.5m distance with wider

perspective angle (> 30 degree) in compared to A-QL.

▪ If the same cell-size is applied, OFDM brings better performance in compared to A-QL. The bilinear

channel equalizer is used.

Remind Theoretical Aspects

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Technical Contributions

Theoretically analyze the impacts of channel imperfection

Cosine-Fourth Law Blurry Image Impact Temporal and Spatial

sampling error

Nonlinear channel response Pixel Eb/No Clipping Noise

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Technical Contributions

Impact of the Cosine-Fourth Law

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The received illuminance ratio

The attenuation function H The inter-carrier interference I

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Technical Contributions

Practically analyze the impacts of channel imperfection

On-focus condition Blurry condition

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Video – Experimental Channel Analysis

Good-focus condition

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Video – Experimental Channel Analysis

Blurry condition

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Annex:Requirement for

final BER goal 10-5

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Reed Solomon Coding

• Input BER between (10-3 and 10-4) can produce the desired BER at 10-5

Desired BER Input

Convolutional Coding CC(1/4)

Desired BER (raw)

• Raw BER between (10-2 and 10-3) can produce the desired BER at CC layer, corresponding to the final

BER at 10-5

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Convolutional Coding CC(1/3)

Desired BER (raw)

• Raw BER between (10-2 and 10-3) can produce the desired BER at CC layer, corresponding to the final

BER at 10-5

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