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Multi-transceiver simulation modules for free-space optical mobile ad hoc networks Mehmet Bilgi Murat Yuksel mbilgi@cse.unr.edu yuksem@cse.unr.edu Department of Computer Science and Engineering University of Nevada, Reno SPIE Conference on

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Multi-transceiver simulation modules for free-space optical mobile ad hoc networks

Mehmet Bilgi Murat Yuksel mbilgi@cse.unr.edu yuksem@cse.unr.edu

Department of Computer Science and Engineering University of Nevada, Reno

SPIE Conference on Defense, Security and Sensing Orlando, FL

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 1 / 15

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Outline

1

Characteristics of RF and FSO

2

Scope of the Paper

3

NS-2 Contribution Results

4

Summary

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 2 / 15

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Characteristics of RF and FSO

Radio Frequency (RF) Based Communication

Radio Frequency (RF) is a commonly used wireless communication technology Omnidirectional Channel becomes a physical broadcast medium Security and overhearing becomes problematic Increased power consumption It can get through obstacles Rarely gets affected by weather: rain and indoor multi-path propagation Widely deployed in currently used laptops

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 3 / 15

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Characteristics of RF and FSO

Free-Space-Optical Communication

Free-Space Optics (FSO): Can be highly directional It can not get through obstacles Fog, aerosols are main problems Visible light does not require complex multi-path propagation RF and FSO are very different in propagation nature! Difference has implications on higher layers of the networking stack.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 4 / 15

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Scope of the Paper

Our contribution to Network Simulator 2 (NS-2): FSO propagation Directional communication Multi transceiver structures: circular, spherical and array Simple 3-D obstacles: cars, buildings and people Obstacle avoiding mobility generator

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 5 / 15

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Scope of the Paper

Light Intensity

LED Photo Detector Gaussian Distribution

f Light Intensity

LED Normal

x x

Divergence Angle

Figure: Gaussian distribution of light intensity at the receiver plane.

A.1 C . 1 E . 1 D . 1 B.1 F . 1

Figure: Optical noise in FSO transmission: transceivers C.1, D.1, E.1 and F.1 contribute to the noise for the communication between A.1 and B.1.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 6 / 15

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Scope of the Paper

NS Modifications

target [k] down target down target up target down target link layer interface queue MAC wireless phy channel target [0] down target down target up target down target link layer interface queue MAC wireless phy channel

• •
• •

target [n] down target down target up target down target link layer interface queue MAC wireless phy up target channel mac up target mac up target mac up target AODV

wireless channel

alignment list alignment list up target up target Default ns-2 design has single transceiver

(a) Node stucture with separate stack for each transceiver.

down target up target channel

wireless channel

wireless-phy[0] up target down target up target channel

• •

buffer buffer shared buffer link layer interface queue Directional MAC target down target down target mac AODV up target wireless-phy[n] up target

(b) Buffering among multiple transceivers.

Figure: Various types of multi-transceiver wireless node designs in NS-2.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 7 / 15

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Scope of the Paper

Alignment Considerations

A.1 B . 1 C . 1

C.1 B.1 Alignment List

(a) A.1 has bi-directional alignment with both B.1 and C.1

A.1 B . 1 C.1

C.1 B.1 Alignment List

(b) A.1 has

uni- directional alignment with C.1

A.1 B.1 C . 1

C.1 B.1 Alignment List

(c) A.1 has lost alignment with C.1

A.1 B . 1 D . 1

C.1 B.1 Alignment List

(d) D.1 gets in the LOS of A.1

Figure: Types of possible alignment loss/gain during a timer period.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 8 / 15

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NS-2 Contribution Results

Power Reception

0.005 0.01 0.015 0.02 0.025 0.03 0.035 5 10 15 20

Received Power (W) Separation (m) Received Power

5e-05 0.0001 0.00015 0.0002 0.00025 0.0003 0.00035 0.0004 0.00045 0.0005 49994 49996 49998 50000 50002 50004 50006

Received Power (W) Location in Y (m) Received Power

Mobility effect on throughput.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 9 / 15

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NS-2 Contribution Results

Error Probability

0.2 0.4 0.6 0.8 1 10000 10500 11000 11500 12000 12500 13000 13500 14000 14500

Error Probability Separation (m) Theoretical Bit Error Probability vs Separation

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 49600 49700 49800 49900 50000 50100 50200 50300 50400

Error Probability Location in Y (m) Theoretical Bit Error Probability vs Separation

Mobility effect on throughput.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 10 / 15

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NS-2 Contribution Results

Error Probability and Simulated Packet Error

0.2 0.4 0.6 0.8 1 0.037 0.0375 0.038 0.0385 0.039 0.0395 0.04 0.0405 0.041 0.0415

Error Visibility (km) Effect of Visibility on Error Theoretical Bit Error Probability Simulated Packet Error

0.2 0.4 0.6 0.8 1 2e-05 4e-05 6e-05 8e-05 0.0001 0.00012 0.00014 0.00016 0.00018 0.0002 0.00022

Error Noise (W) Effect of Noise on Error Visibility: 6 km Range: 0.1 km Noise: 1.143e-12 W Θ: 1 rad Theoretical Bit Error Probability Simulated Packet Error

Mobility effect on throughput.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 11 / 15

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NS-2 Contribution Results

Mobility Simulations

500 1000 1500 2000 2500 3000 0.01 0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Throughput (MB) Mobility (m/s) Mobility Effect on Throughput

4 Txc, Θ=1 rad 8 Txc, Θ=.5 rad 16 Txc, Θ=.25 rad RF 10 100 1000 10000 0.01 0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Throughput (MB, log-scale) Mobility (m/s) Mobility Effect on Throughput

4 Txc, Θ=1 rad 8 Txc, Θ=.5 rad 16 Txc, Θ=.25 rad RF

Mobility effect on throughput.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 12 / 15

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Summary

MANET nodes with multi-element FSO structures exhibit a behavior of intermittent connectivity. Buffering must be considered to exploit the optical speeds.

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 13 / 15

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Summary

Thanks

Thank you!

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 14 / 15

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Summary

Questions

Questions?

M. Bilgi & M. Yuksel (UNR)

FSO MANETs SPIE, April 2010 15 / 15