Multi-transceiver simulation modules for free-space optical mobile - PowerPoint PPT Presentation

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

Outline Characteristics of RF and FSO 1 Scope of the Paper 2 NS-2 Contribution Results 3 Summary 4 M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 2 / 15

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

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

Scope of the Paper 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

Scope of the Paper Light Intensity Gaussian Distribution of Light Intensity Divergence Angle x LED Normal LED x Photo Detector Figure: Gaussian distribution of light intensity at the receiver plane. C 1 . 1 D . A.1 B.1 1 E . 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

Scope of the Paper NS Modifications Default ns-2 design has single transceiver AODV AODV target [0] target [n] target target [k] link layer link link link mac layer layer mac layer down mac mac target down down down target target target interface interface interface interface queue queue queue queue down • • • down • • • down down target target target target up Directional MAC up up up MAC MAC MAC target target target target down down down down down up shared up target target up up up target target target buffer target target target target target alignment list wireless alignment list wireless wireless buffer buffer wireless-phy[0] wireless-phy[n] phy phy phy channel channel channel channel channel • • • up up up up up target target target target target wireless channel wireless channel (a) Node stucture with separate stack (b) Buffering among multiple for each transceiver. 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

Scope of the Paper Alignment Considerations 1 B . 1 B . A.1 A.1 C.1 C . 1 Alignment List Alignment List B.1 B.1 C.1 C.1 (a) A.1 has bi-directional (b) A.1 has only uni- alignment with both B.1 and directional alignment with C.1 C.1 . 1 B.1 B A.1 A.1 C . 1 D . 1 Alignment List Alignment List B.1 B.1 C.1 C.1 (c) A.1 has lost alignment (d) D.1 gets in the LOS of with C.1 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

NS-2 Contribution Results Power Reception Received Power Received Power 0.035 0.0005 0.00045 0.03 0.0004 Received Power (W) Received Power (W) 0.025 0.00035 0.0003 0.02 0.00025 0.015 0.0002 0.00015 0.01 0.0001 0.005 5e-05 0 0 0 5 10 15 20 49994 49996 49998 50000 50002 50004 50006 Separation (m) Location in Y (m) Mobility effect on throughput. M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 9 / 15

NS-2 Contribution Results Error Probability Theoretical Bit Error Probability vs Separation Theoretical Bit Error Probability vs Separation 1 1 0.9 0.8 0.8 0.7 Error Probability Error Probability 0.6 0.6 0.5 0.4 0.4 0.3 0.2 0.2 0.1 0 0 10000 10500 11000 11500 12000 12500 13000 13500 14000 14500 49600 49700 49800 49900 50000 50100 50200 50300 50400 Separation (m) Location in Y (m) Mobility effect on throughput. M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 10 / 15

NS-2 Contribution Results Error Probability and Simulated Packet Error Effect of Visibility on Error Effect of Noise on Error 1 1 Visibility: 6 km Range: 0.1 km 0.8 0.8 Noise: 1.143e-12 W Θ : 1 rad 0.6 0.6 Error Error Theoretical Bit Error Probability Theoretical Bit Error Probability Simulated Packet Error Simulated Packet Error 0.4 0.4 0.2 0.2 0 0 0.037 0.0375 0.038 0.0385 0.039 0.0395 0.04 0.0405 0.041 0.0415 2e-05 4e-05 6e-05 8e-05 0.0001 0.00012 0.00014 0.00016 0.00018 0.0002 0.00022 Visibility (km) Noise (W) Mobility effect on throughput. M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 11 / 15

NS-2 Contribution Results Mobility Simulations Mobility Effect on Throughput Mobility Effect on Throughput 3000 10000 4 Txc, Θ =1 rad 4 Txc, Θ =1 rad 8 Txc, Θ =.5 rad 8 Txc, Θ =.5 rad 16 Txc, Θ =.25 rad 16 Txc, Θ =.25 rad RF RF 2500 Throughput (MB, log-scale) Throughput (MB) 2000 1000 1500 1000 100 500 0 10 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 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 Mobility (m/s) Mobility (m/s) Mobility effect on throughput. M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 12 / 15

Summary 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

Summary Thanks Thank you! M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 14 / 15

Summary Questions Questions? M. Bilgi & M. Yuksel (UNR) FSO MANETs SPIE, April 2010 15 / 15