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Ultra-High-Speed Wireless Ad-Hoc Networks using Free-Space-Optics (FSO). Shiv Kalyanaraman, Murat Yuksel, Partha Dutta shivkuma@ecse.rpi.edu. : “ shiv rpi ”. Motivations: Free-Space-Optical (FSO) Ad-Hoc Networks: Mobile or Fixed Multi-Hop. Application: Mixed RF/FSO Ad-Hoc Networks
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Ultra-High-Speed Wireless Ad-Hoc Networks using Free-Space-Optics (FSO) Shiv Kalyanaraman, Murat Yuksel, Partha Dutta shivkuma@ecse.rpi.edu : “shiv rpi”
Motivations: Free-Space-Optical (FSO) Ad-Hoc Networks: Mobile or Fixed Multi-Hop Application: Mixed RF/FSO Ad-Hoc Networks (Military Application)
Free-Space-Optical Communications (FSO) Ad Hoc Networking High bandwidth Low power Directional Mobile communication Auto-configuration Free-Space-Optical Ad Hoc Networks Spatial reuse and angular diversity in nodes Low power and secure Electronic auto-alignment Optical auto-configuration (switching, routing) Bringing Optical Communications and Ad Hoc Networking Together…
Current Commercial FSO Point-to-Point Links in dense metros, competing with “wires” and “leased lines” Issue: How to achieve link reliability/availability despite weather
Ad-Hoc/Meshed Optical Wireless: Why? • Positive points: • High-brightness LEDs (HBLEDs) are very low cost and highly reliable components • 35-65 cents a piece, and $2-$5 per transreceiver package + upto 10 years lifetime • Very low power consumption (100 microwatts for 10-100 Mbps!) • Even lower power for 1-10 Mbps • 4-5 orders of magnitude improvement in energy/bit compared to RF • Directional => Huge spatial reuse => multiple parallel channels for huge bandwidth increases due to spectral efficiency • More Secure: Highly directional + small size & weight => low probability of interception (LPI) • Issues: • Need line-of-sight (LOS); and alignment of LOS & network auto-configuration • Need to deal with weather & temporary obstacles, alignment loss Challenge: leverage huge benefits while tackling problems.
Optical Wireless: Commodity components LEDs… VCSELs… IrDAs… Lasers… Many FSO components are very low cost and available for mass production.
Node 1 Node 2 D D/N … Node 2 Node 1 Repeater 2 Repeater N-1 Repeater 1 Spatial Re-use: 2D FSO Arrays: 1-100Gbps Backhaul • 1cm2 LED/PIN => 1000 pairs in 1ft x 1ft square structure • 100 Gbps aggregate bandwidth (= 1000 x 100 Mbps)
Aggregate Capacity in 2-d Arrays: Interference vs Density vs Distance Bandwidth-Volume Product Interference Error vs. Packaging Density
LED Micro Mirror PhotoDetector Spherical Antenna Cluster of FSO Components Optical Transmitter/Receiver Unit LOS Step1: LOS Detection Through the use of Spherical FSO Antenna Array Step2: Links Set-Up by Bundling LOS’ through Mirror adjustments for each LED-Photodetector Units Auto-Alignment: 3D Spherical FSO Structures
Initial Ad-Hoc FSO Prototypes (contd) Very dense packaging and high mobility are feasible. Received Light Intensity from the moving train. Misaligned Aligned
Initial FSO Prototypes Inside of the sphere is coated w/ mirror Photo-detector Integrating ball to increase angle of reception – inside is coated with mirror.
Audio Transmission on FSO Link using low cost LED’s and Photo Diodes: Two Channel Mixing a) Two transmitters on different channels b) Single receiver and circuit for both the channels Indoor FSO ad-hoc networks
Time of flight - angle of arrival Auto-configuration: Location tracking and management • Location tracking: (optional integration w/ GPS) • Use highly granular spherical FSO antennas(e.g. hundreds of transceivers) can detect angle of arrival • Use time of flight or signal strength can detect distance • Unlike RF, no need for triangulation: sense of direction is available. • Allows easy integration with Community Wireless Networks (CWNs) • Organic network growth
Emerging Apps: Broadband Sensor Networks: Eg: Mobile/Fixed Camera Networks • Thousands of un-supervised and moving cameras w/o centralized processing or control • Key: Mix of Low Power AND High Speed AND Ad-Hoc/Unsupervised • More than 10,000 public and private cameras in Manhattan, 2.5 million in the UK! • Subways, airports, battlefields, factory floors, highways…
SUMMARY: Ultra-Broadband Wireless: puzzle falling in place… • (1)Infinite Spectrum in Thin Air! • Key: use unlicensed spectrum or larger licensed bands • (2) Multi-hop architecture w/ Base-Station Interfaces • Wireless is fundamentallycheap for shorter distances, smaller coverage • Organic architecture: auto-conf, self-management (10+ years of research in ad-hoc networks), community wireless • IP/geographic routing, fully distributed traffic engineering mechanisms • Technology neutral, extensible, modular: 802.11x, 802.16x, FSO • (2a) Multi-hop Free-space-optics (FSO) using ultra-low-cost components for 100 Gbps+ capabilities • Key: Broadband CWNs & ad-hoc FSO complementary to ongoing advances in FTTH, DSL/Cable, WiMax, 3G rollouts. • Open Problems in upgrading the network and transport layers to leverage raw, but distributed bandwidth, and tolerate higher bursty losses (weather related)
Thanks! Student Heroes: Jayasri Akella, sri@networks.ecse.rpi.edu Dr. Murat Yuksel (post-doc): yuksem@ecse.rpi.edu Chang Liu, c.liu@ee.unimelb.edu.au David Partyka, partyd@rpi.edu Sujatha Sridharan Bow-Nan Cheng:chengb@rpi.edu (CWN project) : “shiv rpi”