<Fundamentals and PHY>#1570146193

SINR Analysis of OFDM Systems Using a Geometry-Based Underwater Acoustic Channel Model

Do Viet Ha∗ , Nguyen Van Duc∗ , Matthias Pätzold† ∗Hanoi University of Science and Technology, Ha Noi, Viet Nam

†University of Agder P.O. Box 509, 4898 Grimstad, Norway

Outline

▪Motivation & Research Objectives

▪UWA Geometry-based channel model

▪ICI and Noise Analysis

▪Numerical results

▪Conclusions

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Motivation and Objectives

▪ Underwater acoustic channel models

▪ The ICI has strong effect in UAC systems

▪ The ambient noise is not white noise

▪ SINR analysis: the ICI effect in combination with ambient noise

▪ Models for simulation studies

3

UWA Geometry-based channel model [1]

▪ For a shallow water environment.

▪ Randomly distributed scatterers.

▪ Method of equally spaced scatterers (MESS)

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Geometry-based shallow UWA channel model

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[1] M. Naderi, M. Pätzold, and A. G. Zajic, “A geometry-based channel model for shallow underwater acoustic channels under rough surface and scattering conditions,” in Proc. 5th International Conference on Communication and Electronics, ICCE 2014. Da Nang City, Vietnam, pp. 112–117, Aug. / Sep. 2014.

ICI Analysis of UWA-OFDM systems

▪ Using the geometry-based UWA channel model

▪ Doppler effect in UWA-OFDM systems

▪ SIR analysis

▪ SINR analysis

5

SIR calculation

▪ Analyze the desired signal and the interference signal

▪ Using the time correlation function.

▪ Not depend on transmit power

6

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SIR S

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Desired signal power

Interference power

Time correlation function

SIR Analysis

▪ SIR increases with

▪ Larger bandwidth

▪ Lower Doppler frequency

SIR for various values of the maximum Doppler frequency.

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SINR calculation

▪ Both the ICI and ambient noise effect

▪ SINR calculation

▪ Depend on transmit power

8

SINRR

S

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P P

Desired signal power

Interference power Noise power

Transmit power ▪ Need to be carefully determined

▪ which SNR should be achieved ?

9

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SNR

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PSD of ambient noise

Acoustic attenuation

3 dB Bandwidth

Given SNR

Transmission distance

SINR versus SNR

▪ Proper SNR to restrict the ICI effect.

▪ Threshold of SNR: 20dB

SINR for various values of the maximum Doppler frequency

10

Transmit power

▪ Long transmission distance low carrier frequency.

Required transmit power versus transmission distance for different carrier frequencies

11

Ambient Noise Power

▪ Depend on

▪ Signal frequency

▪ Boat activity, the speed of wind

12

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[2] A. Abdollah Doosti, J. Mohammad Javad, and V. Vahid Tabataba, “Design and simulation of a secure and robust underwater acoustic communication system in the persian gulf,” Communications and Network, vol. 3, no.2, 2011

Ambient noise level for different frequency domains [2].

The ICI and Ambient noise power

▪ Increased bandwidth

▪ ICI power decreases

▪ Noise power increases

Noise power and ICI power for different values of the maximum Doppler frequency

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SINR analysis

▪ Doppler effect is strong in narrow bandwidth.

▪ Chose suitable bandwidths

▪ Channel capacity consideration

▪ Trade bandwidth for SINR and vice versa.

SINR for various values of the maximum Doppler frequency

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Conclusion

▪ UWA channels : characteristics, ambient noise, Doppler effect

▪ Analyze both the ICI and the noise effect.

▪ Practical guidelines for UWA-OFDM system design.

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Thank you for your attention Q&A

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