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US Navy Seaweb program Seaweb Undersea acoustic sensing, signaling, communications & networks Networked through-water digital com/nav Scalable wide-area wireless grid Composable architectural flexibility Fixed and mobile autonomous nodes Gateways to command centers Persistent and pervasive Low source level, wide band, high freq Sponsors: ONR, PEO LMW, SOCOM PEO IIS, CTTSO, TRANSEC attributes PEO C4I & Space, PEO IWS, OSD, DARPA, SBIR Integrating sensors, UUVs, SSNs Collaborations: TTCP Unet (Undersea networking) DARPA DTN (Disruption-Tolerant Networking) ONR DADS (Deployable Autonomous Distributed Sys) ONR ASAP (Adaptive Sampling & Prediction) OSD Coalition Warfare Seaweb is in routine use by several client programs POC: [email protected], (831) 402 5666 J. Rice, “Enabling Undersea FORCEnet with Seaweb Acoustic Networks,” Biennial Review 2003, SSC San Diego TD 3155, pp. 174-180, Dec 2003 1 US Navy Seaweb program Applied research, “Discovery & Invention”, 6.2 funding Art of the possible for Maritime sensor networks & Undersea Distributed Networked Systems (UDNS) Seaweb Iridium satellite Ashore & afar command centers Racom buoy with Iridium, FreeWave, Telesonar UUVs SDV Telesonar repeater nodes SSN/SSGN with Seaweb server ASW / ISR / Float MCM nodes Telesonar modem Acoustic release Weight 2 SPAWAR SBIR topic N93-170 advanced and commercialized DSP-based acoustic comms Seaweb SBIR contractor: Teledyne Benthos (formerly Datasonics, Inc.) Pre-SBIR ATM-845 ATM-865 1993-97 all analog 10 b/s FSK SBIR Phase-2 ATM-875 1997-99 TMS320C50 2nd generation telesonar Spiral development SBIR Phase-3 ATM-885 2000-2007 TMS320C5410 3rd generation telesonar Spiral development SBIR Phase-1 ATM-850 (not shown) 1995-97 Multi-band MFSK 1st generation telesonar Technology transfer from MIT/WHOI 1997-2003 achievement: Stable COTS hardware COTS & Navy firmware 8X less expensive 40X more efficient 2007: 4th gen telesonar with TRANSEC features 3 TBED Seaweb Navy’s first experimental digital sensor network 1995-96 “TBED” Telemetry Buoy Environmental Data NSWC Coastal Systems Station, Panama City, FL Objective: telemeter environmental data from distributed seafloor sensor nodes to one or more gateway nodes Sea test in 1996 Gulf of Mexico, 60 km offshore Panama City, 45-m water 8-km node-to-node ranges achieved 4 Datasonics ATM-850 telesonar modems 150-bit/s, 1024-bit messages Flooding protocol designed for up to 10 nodes Advantages: Simple, COTS modem firmware, Plug & play, Routing tables not required, Centralized control not required Disadvantages: Redundant communications, Not bandwidth efficient for fixed network, High latency Analogous to terrestrial “Zebranet” Well suited for delay-tolerant AUV mobile networks J. Rice, et al, “Evolution of Seaweb Underwater Acoustic Networking” Proc IEEE Oceans 2000 4 Seaweb ’98 engineering experiment Seaweb Buzzards Bay, MA, September 1999 An undersea wireless sensor network employing ten telesonar modems and an RF gateway buoy 41°43´ 10-m water depths 10 ATM-875 telesonar modems 3-FDMA 3 sensor nodes FreeWave gateway Bi-directional routing tables Scaleable architecture ATM-875 Isobath contours at 5-meter intervals 1 km 70°46´ M. D. Green, J. A. Rice and S. Merriam, “Underwater acoustic modem configured for use in a local area network,” Proc. IEEE Oceans ’98 Conf., Vol. 2, pp. 634-638, Nice France, September 1998 Racom-1 41°35´ 70°36´ 5 Seaweb ’99 engineering experiment Seaweb Buzzards Bay, MA, August 1999 SSC San Diego, Delphi, Benthos, SAIC FreeWave 900-MHz LOS gateway Cellular Digital Packet Data (CDPD) gateways Seaweb server 15 ATM-875 nodes Seaweb ‘99 firmware FDMA-6 network Node addressing Ranging Handshake protocol Adaptive power control Remote-controlled routing Commercial sensors J. Rice, et al, “Evolution of Seaweb Underwater Acoustic Networking” Proc IEEE Oceans 2000 6 Seaweb 2000 engineering experiment Seaweb Buzzards Bay, Aug-Sept 2000 ATM-885 modems FreeWave LOS gateway Cellular Digital Packet Data (CDPD) gateways Asynchronous TDMA Rerouting RTS/CTS handshake + ARQ Isobath contours at 5-meter intervals 7 Demonstrated capabilities: FRONT ocean observatory Seaweb National Oceanographic Partnership Program FRONT-3 March-June, 2001 FRONT-4 Jan-June, 2002 Concept D. L. Codiga, et al, “Networked Acoustic Modems for Real-Time Data Telemetry from Distributed Subsurface Instruments in the Coastal Ocean: Application to Array of BottomMounted ADCPs,” J. Atmospheric & Oceanic Technology, June 2005 8 Seaweb US participation in Canada’s ICESHELF 2002 April experiment in the Arctic Ocean 80-150 m water covered by rough ice of 2-8 m thickness and large subsurface ridges and keels Upward-refracting water Ice-mounted Seaweb network, first test of acoustic networking in the Arctic Prepares for RDS-4 experiment with interoperable US and Canadian ASW sensor nodes 9 Demonstrated capabilities: Racom buoy Seaweb FBE India June 2001 (Prior Seaweb tests with USS Dolphin submarine: Sublinks ’98, ’99, 2000) SSN with BSY-1 sonar Seaweb TEMPALT Ashore ASW command center Seaweb server at SSN and ASWCC Acoustic chat and GCCS-M links to fleet SSN/MPA cooperative ASW against XSSK Flawless ops for 4 continuous test days Experimental DADS sensor node J. Rice, et al, “Networked Undersea Acoustic Communications Involving a Submerged Submarine, Deployable Autonomous Distributed Sensors, and a Radio Gateway Buoy Linked to an Ashore Command Center,” Proc. UDT Hawaii, October 2001 10 Seaweb message example: Multi-Access Collision Avoidance (MACA) Internet Protocol (IP) Source node Seaweb Fixed routing tables Precursor to Seaweb cellular routing Destination node G. Hartfield, Performance of an Undersea Acoustic Network during Fleet Battle Experiment India, MS Thesis, Naval Postgraduate School, Monterey, CA, June, 2003 11 Demonstrated capabilities: Seaweb Seaweb network with UUVs US/Canada collaboration Gulf of Mexico, Feb 1-8, 2003 UUV nose section Over-the-horizon command center Iridium satellite radio links Shipboard command center 2 Racom buoy gateway nodes FreeWave radio links Mobile gateway nodes Mobile sensor nodes 200 km logged by UUVs 6 fixed repeater nodes 3 glider UUV mobile nodes 300 hrs logged by UUVs Node-to-multinode comm/nav 12 Seaweb navigation development Seaweb Seaweb 2005 UUV Experiments Monterey Bay, May 9-11, July 20-22 St. Andrews Bay, December 5-9 Iridium satellite constellation Racom buoy gateway node GPS satellite constellation Shipboard command center ARIES UUV NPS M. Hahn, Undersea Navigation via a Distributed Acoustic Communications Network, MS Thesis, Naval Postgraduate School, June 2005 S. Ouimet, Undersea Navigation of a Glider UUV using an Acoustic Communications Network, MS Thesis, Naval Postgraduate School, Sept 2005 Slocum UUV EMATT UUV constellation of 6 Seaweb repeater nodes fixed on seabed M. Reed, Use of an Acoustic Network as an Underwater Positioning System, MS Thesis, Naval Postgraduate School, June 2006 13 Demonstrated capability: Seaweb All Seaweb communications yield the node-to-node range as a by-product of the link-layer RTS/CTS handshake. The broadcast ping command returns ranges to all neighboring nodes. (a) Networked command (b) Broadcast ping (c) Echoes (d) Networked telemetry 14 Seaweb cellular grid deployment Theater ASW Experiment – TASWEX 04 Submarine comms @ speed & depth (CSD) Seaweb Average speed 6.5 knots Average 1 repeater every 20 min 15 Seaweb 16 Seaweb 2004 grid post mortem Seaweb Impacted by trawling along the 300-m isobath 3 nodes removed, 6 nodes displaced or damaged COMEX FINEX FINEX H. Kriewaldt, Communications Performance of an Undersea Acoustic Wide-Area Network, MS Thesis, Naval Postgraduate School, December 2005 17 Seaweb 2005 experiment Seaweb February 2005, Panama City, FL SRQ link-layer mechanism NSMA (Neighbor Sense Multiple Access, a cross-layer variation on CSMA) Ranging and node localization Iridium-equipped Racom buoy Compressed image telemetry NPS, SSCSD, CSS, Benthos 18 Demonstrated capability: Selective Automatic Repeat Request (SRQ) is a link-layer mechanism for reliable transport of large datafiles even when the physical layer suffers high BERs Node A 1. Node A initiates a link-layer dialog with Node B. Seaweb Node B RTS CTS 2. Node B is prepared to receive a large Data packet as a result of RTS/CTS handshaking. HDR 4. Node B receives 12 subpackets successfully; 4 subpackets contained uncorrectable bit errors. 3. Node A transmits a 4000-byte Data packet using 16 256-byte subpackets, each with an independent CRC. 5. Node B issues an SRQ utility packet, including a 16-bit mask specifying the 4 subpackets to be retransmitted. 6. Node A retransmits the 4 subpackets specified by the SRQ mask. SRQ HDR 7. Node B receives 3 of the 4 packets successfully (future implementation of cross-layer time-diversity processing will recover 4 of 4). B issues an SRQ for the remaining subpacket. 8. Node A retransmits the 1 subpacket specified by the SRQ. SRQ 9. Node B successfully receives and processes Data packet. HDR J. Kalscheuer, A Selective Automatic Repeat Request Protocol for Undersea Acoustic Links, MS Thesis, Naval Postgraduate School, June 2004 19 Seaweb Seaweb telesonar repeater node Seaweb telesonar modem, circa 2000-2007 Texas Instruments TMS320C5410 DSP Teledyne Benthos COTS hardware US Navy firmware Spectral bandwidth = 5 kHz (9-14 kHz) SL = 174 dB (typ) re 1μPa @ 1m Modulation = Multi-channel 4-FSK Forward Error Correction Raw bit rate = 2400 bit/s Data packets = 800 b/s Utility packets = 150 b/s DI = 0 dB (omni) DI = 0 dB (omni) K. Scussel, “Acoustic Modems for Underwater Communications,” Wiley Encyclopedia of Telecommunications, Vol. 1, pp. 15-22, Wiley-Interscience, 2003 20 Small Business Innovative Research SBIR N03-224 is producing the 4th-gen telesonar modem Seaweb Contractor: Teledyne Benthos, Inc. Sponsor: PEO C4I & Space, PMW 770 Transmit/Receive Board Digital Board ATM-885 board set New ATM-900 board set Spectral bandwidth up to 20 kHz, Operating frequency up to 70 kHz Processing speed increased by 2X, Memory increased by 20X Xmit efficiency improved by 50%, Rcvr efficiency improved by 50% One new digital board can support 4 T/R boards (for multi-band, MIMO, spatial diversity, etc) SBIR Ph-2 Option will integrate SBIR N99-011 directional ducer (Image Acoustics, Inc) SBIR Ph-3 5-year delivery-order contract being negotiated by SSC San Diego 21 Current work The Seaweb network organizes and maintains itself under the control of autonomous master nodes or Seaweb servers at command centers Preparation 5 days Installation 1 day Activation 1 hr Seaweb Analyze mission requirements Measure or predict environment Model transmission channels Predict connectivity range limits Specify spacing, aperture, and node mix Pre-program master node only Obey spacing constraints Test master node link to gateway Awaken network nodes Discover neighbors Initiation 2 hrs Obtain reciprocal channel response Perform 2-way ranging Sound own depth Initialize spectral shaping Registration 1 hr Report link data & node configuration Assimilate data at master node Optimization 1 hr Compute optimal/alternate routes Assign protocols Operation 90 days Monitor energy, links, and gateways Optimize life, TRANSEC, and latency 22 Current research Seaweb Adaptive modulation Node A Node B RTS Demodulate RTS transmission Reconstruct transmitted waveform Estimate channel scattering function CTS Specify Data-packet comms parameters Determine h(τ, t ) / Doppler / SNR S. Dessalermos, Undersea Acoustic Propagation Channel Estimation, MS Thesis, Naval Postgraduate School, Monterey, CA, June 2005 Data Decision Map channel characteristics against available repertoires and signal techniques 23 Seaweb Current research Asymmetric links Low-rate C2 Submarine High-rate data telemetry Autonomous node 24 Unet through-water acoustic signaling range regimes Seaweb Categorized at Unet Workshop 5 and refined at Unet Workshop 6 Range regime Node-to-node range (m) Frequencies (kHz) Use Very short 5 – 50 >100 Proximity communications, e.g., Seamule Short 50 – 500 30-100 Local-area networks, e.g., Seastar Medium 500 – 5k 8-30 Wide-area networks, e.g. Seaweb Long 5k – 50k 1-8 Tactical paging Very long 50k – 500k <1 Blue-water paging 25 Seaweb Acoustic link budget Each term in the standard radio link budget is analogous to specific quantities in the sonar equation. SNR(f) = PSL(f) – TL(f) – AN(f) + DIxmt(f) + DIrcv(f) We develop the acoustic link budget as a wideband model because, unlike most radio channels, the acoustic channel exhibits strong frequency dependency. PSL pressure spectrum level Pxmt AN DIxmt TL DIrcv SNR Prcv 26 Sonar equation analysis (TL+AN) for 500-m range and 4 noise spectra Seaweb TL + NSL (dB re 1μPa) PSL W= 20kHz Frequency (kHz) 27 Current research Seastar local-area networks Seaweb Asymmetric links: high-BW links from peripheral nodes to central node; low-BW links from central node to peripherals and peer-to-peer Point-to point communications at short ranges (50 to 500 m) employ the 30-100 kHz band Seaweb WAN Data are fused/beamformed at the central node Seastar LAN increases the carrying capacity of the undersea environment by an order of magnitude Central node reports compressed information through the wide-area network Applications include sensor arrays, sensor clusters, autonomous MCM vehicles, and SDV/DDS dive teams DADS magnetometer array a near-term pilot application Seastar LAN Prototype Seastar at AUVfest 2007, 2 NPS thesis students ONR 321MS 6.2 funding 28 Over 40 Seaweb deployments Seaweb Spirally developed USW com/nav capability NPS Iceweb, 2002 Q272 Seaweb GoM, 2003 G K R G U GHGK U R Q FBE-I, 2001 R R RDS-4, 2002 FRONT-4, 2002 TASWEX04 Seaweb NSW, 2004 29