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The Architecture of Metricom’s MicroCellular Data Network™ (MCDN) and Details of its Implementation as the Second and Third Generation Ricochet™ Wide-Area Mobile Data Service. Dr. Mike Ritter Chief Technology Officer Wednesday, 9 May 2001 Robert J. Friday, Chief Scientist
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The Architecture of Metricom’s MicroCellular Data Network™ (MCDN) and Details of its Implementation as the Second and Third Generation Ricochet™ Wide-Area Mobile Data Service. Dr. Mike Ritter Chief Technology Officer Wednesday, 9 May 2001 Robert J. Friday, Chief Scientist Michael Cunningham, V. P. of QA
Metricom’s Technology Unique and Patented Technology MicroCellular Data Network Built from the Ground up to Support High-Speed Data In Public and Private Spectrum
What is Ricochet? • Ricochet Service • Wide Area, high-speed, mobile wireless access to information (Internet, Intranet, LAN…) • Fastest wide area mobile information access solution in the market since 1995 • Next generation 128 kbps technology deployed in 13 United States markets • Ricochet Technology • MicroCellular Data Network (MCDN) • Radio Frequency (public and private spectrum) + Internet Protocol (IP) • Spread Spectrum, Frequency Hopping • Proprietary DSP, coding, and network algorithms • Packet data from inception
Competing wireless service = • 9 – 14 kbps • Ricochet Wireless Service = • 128 – 200 kbps 10 x • 500 Megabytes per month • 500 kilobytes per month 1000 x MCDN’s Advantages Wireless InternetRicochet Network = Bandwidth = Capacity = Speed
Key Design Advantages • Intelligent MicroCell technology • More capacity • More coverage via dense deployment • Instantaneous handoff and mobility • Built-in roaming • Scalable and robust • Packet-based (not circuit-switched) • Mesh network (not hub-and-spoke) • Self-healing, self-configuring & load-balancing • Standard IP
Modem Internet and Corporate Networks Wired Access Point Network Interface Facility Ricochet System Diagram 2.3 GHz 900 MHz PoletopRadio 2.4 GHz High-speed dedicated wired connections
Modem Interface to the Network • RF Physical Layer • 500 kbps QPSK on the downlink • 750 kbps 16 QAM optional - 2x performance • 200 kbps 4 FSK on the uplink • 500 kbps QPSK optional – 2x performance • Half-duplex, 1 Watt into a 0dBi ant., -100 dBm Rx. Sensitivity • Network Protocols • Transport Layer guarantees ordered delivery of packets from the gateway to the modem • Routing Layer that routes encapsulated IP packets from the gateway to the modem • Data link Layer that guarantees delivery of packets between radios
MicroCell Radio Flexibility Radio Features ---------------------------- Multiple Modulations Quad 2.4 GHz Antennas 900 MHz Omni Antenna Software Radio Design Dual Band Operation Simultaneous Tx/Rx System Flexibility ----------------------- Software Downloadable Error Correction Coding Fragmentation Priority / Buffer Storage SNMP Modulation Formats ---------------------------- 2-FSK; 100 ksps; 100 kbps 4-FSK; 100 ksps; 200 kbps QPSK; 125/250 ksps; 250/500 kbps 16 QAM; 250 ksps; 1000 kbps 32 QAM; 250 ksps; 1250 kbps
Wired Access Points • WAP hardware similar to cellular base station functionality at a fraction of the cost. • Typically located on towers or rooftops • One WAP supports 55-60 poletop radios • One WAP covers 11.5 sq. miles • 12 Radios installed for intial coverage • Packets routed by an enterprise-class IP switch • WAPs connect to a Network Interface Facility with high-speed dedicated WAN connections (T-1s, DS-3s)
Network Interface Facility (NIF) • The NIF serves as the aggregation point for all WAP circuits • A NIF has standard IP routers and switches and MCDN gateways • The NIF provides the network connection to Channel Partners via L2TP tunnels • All NIFs co-located in WCOM or Level3 facilities
Future of MCDN Technology • 2x performance with new modems • 4G System prototypes under design • T1/E1 rates to users (>>1 Mbps) • 10x capacity • Same architecture • Replaced infrastructure • New backhaul (5.x GHz unlicensed)
MCDN 3G(2X) • Software Upgrades to Poletops and WAPs • Increased Radio Link Performance and Capacity • No MicroCell Modifications • State-of-the-Art Radios Already Deployed • New Modems Based on New Chip Set • Silicon Integration • New & Improved Antennae at WAPs • Increased Capacity and Performance
MCDN 4G • New Infrastructure and Modems • Additional Spectrum for Backhaul Allows an Increase in Capacity • 5.8 GHz Public Spectrum • 5.7 GHz UNII Band • New Radio Technology to Improve Speed • Wideband Radios • Increased Miniaturization and Decreased Cost • Move to DSL-like Protocols to Wireless • Continue to Improve and Extend Metricom’s MCDN Architecture