Best Practices for Building Ultra-Low Latency Microwave Networks

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Aviat Networks describes best practices for building ultra-low latency microwave radio networks

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Best Practices for Building Ultra-Low Latency Microwave Networks

  1. 1. BEST PRACTICES FOR BUILDING ULL NETWORKS 1
  2. 2. PROGRESSION LOW LATENCY NETWORKS over $4B PRE-1970’S 70’-80’s 90’s-TODAY market globally MESSENGER SERVICES, DATA NETWORKS FIBERPHYSICAL/HAND DELIVERY (ANALOG/DIGITAL) ON COPPER AVIAT NETWORKS
  3. 3. NEXT STEP IN LOW LATENCY PROGRESSION:MICROWAVE microwave uses more direct routes (less distance) propagation is 30% faster over air MICROWAVE IS FASTER THAN FIBER AND IS QUICKLY BECOMING DEFACTO STANDARD FOR ULTRA LOW LATENCY TRANSPORT AVIAT NETWORKS
  4. 4. WHAT IS USABLE LATENCY? Functional, viable, practical. ??? AVIAT NETWORKS
  5. 5. BUT MICROWAVE IS COMPLEX AND NEW TOFINANCIAL SERVICES… Number Co-Existence Network Weather with Fiber Hops (rain, Management propagation)Path Design Installation and ReliabilityRegulatory Issues Latency Sites and Security Acquisition
  6. 6. 3 ULL MICROWAVE QUESTIONS AVIAT NETWORKS
  7. 7. Full size image AVIAT NETWORKS
  8. 8. RELEVANT TECHNICAL CONSIDERATIONSEquipment Latency Payload Interface Serialization Delay Modem TechnologyEnd-to-End Latency Repeaters RF and Modem PerformanceOperational Considerations AVIAT NETWORKS
  9. 9. WHERE DOES LATENCY GO?On a standard latency microwave link SHORT FRAMES (64) LONG FRAMES (1518) 0.15% Interface Speed 3.85% 0.39% 2.11% 0.08% 7.00% Switching & 5.13% Serialization 21.13% 19.26% Transfer Buffers 38.52% 44.07% Interleaving 16.91% 30.82% Encoding/Decoding 10.57% Mod/Demod Analog Front End AVIAT NETWORKS
  10. 10. PAYLOAD INTERFACES AND SERIALIZATION DELAYEthernet InterfacesL1 Interfaces (STM1/OC3)Proprietary L1 Interfaces (Clock and Data) AVIAT NETWORKS
  11. 11. MODEM TECHNOLOGY FEC Method Algorithm Latency SG Imp. Linear and Iterative LPDC, Turbo Codes High HighForward Error Correction Convolutional Codes Viterbi Medium Good Block Codes Reed Solomon Low* Good* 128 QAM 256 QAM 16 QAM 32 QAM 64 QAM No FEC --- Lowest None Mod QPSKBW30 MHz      40 MHz       Modulations and Bandwidths50 MHz      Diversity Protection Improves link availability and hence low latency availabilityAdaptive Modulation and Adaptive Coding  Latency Increase AVIAT NETWORKS
  12. 12. LOW LATENCY… (OBVIOUSLY)SO HOW DO WE REDUCE THE LINK LATENCY?- High speed interfaces ~10-20 µs- Use small frame sizes- Early packet forwarding- Reduce buffering wherever possible BOX- Eliminate Interleaving- Reduce or eliminate FEC And equipment/box latency is easy to understand/measure, but… AVIAT NETWORKS
  13. 13. THE REAL METRIC IS END-END LATENCY(THIS IS WHERE IT GETS COMPLICATED…) BOX BOX BOX Exchange Exchange BOX BOX And best ways to lower end-end MW latency… AVIAT NETWORKS
  14. 14. REDUCE NUMBER AND COMPLEXITY OF THE HOPSINTRODUCTION OF THE REPEATER CONCEPT- Latency in Nx10 ns- RF Repeater - Limited RF Options - Mask Limitations- IF Repeater - Frequency Agile - Mask Limitations Regenerator Repeater Repeater Regenerator Node Node Node Node- Digital Repeater - Frequency Agile - Usually No Mask Limitations 30% reduction AVIAT NETWORKS
  15. 15. ADAPTIVE REPEATER TECHNOLOGY Ultra Low End-End Latency 99% of time Regenerator Repeater Repeater Repeater Repeater Regenerator Node Node Node Node Node Node Low End-End Latency (still better than fiber) Regenerator Repeater Regenerator Repeater Repeater Regenerator 1% of time Node Node Node Node Node Node AVIAT NETWORKS
  16. 16. RF AND MODEM PERFORMANCEWHERE DOES IT HELP?• Link Distance • Antenna Size• Number of Hops • Number of Repeaters• Link Availability• Techniques include:- Tx Power - FEC Coding- Rx Sensitivity - Rx Threshold- Diversity - Higher Quality OscillatorsUltimately all revolves around having better System Gain !!! AVIAT NETWORKS
  17. 17. QUANTIFY RF / MODEM PERFORMANCEExample: Chicago rain zone, 99.999 Availability, 6 Ft Antenna, 64QAM Frequency Band Std System Gain +3dB 6 GHz 51.6 Miles 55.8 Miles 11 GHz 35.1 Miles 38.5 Miles AVIAT NETWORKS
  18. 18. AND MANAGING THE RELIABILITY /LATENCY TRADEOFF High Latency End-End Good News: with Latency new innovations, best of both worlds Low Latency can be achieved… 90% 99.999% Path Uptime AVIAT NETWORKS
  19. 19. SO THAT’S LOW LATENCY…BUT what good is low latency if your network is: Thus a full featured microwave solution will be required AVIAT NETWORKS
  20. 20. BEST PRACTICEFOR BUILDING LOW LATENCYMICROWAVE NETWORKS:FOCUS ON END-END LATENCYUSING A FULL-FEATUREDMICROWAVE PLATFORM AVIAT NETWORKS
  21. 21. AVIAT NETWORKS
  22. 22. ULL MICROWAVE LIFECYCLEAnd path planning is more than just GPS Coordinates and Google Maps! AVIAT NETWORKS
  23. 23. VALIDATE THE ROUTEPhase 1 - Planning and Design• Regulatory• Site Selection• Frequency Coordination and Acquisition• Transmission and Network Engineering• Site & Path SurveyIs the route viable? AVIAT NETWORKS
  24. 24. SECURE THE SITESSite Acquisition and Construction• Site Acquisition and Leasing• Engineering and Drafting• Zoning• Utilities and Construction• System Engineering and Optimization AVIAT NETWORKS
  25. 25. BUILD AND LAUNCH THE NETWORKIntegration and Deployment• Configuration and Network Engineering• Factory Integration• Equipment Staging• Installation of Antennas, Lines & Ground Equipment• Radio Installation and Path Alignment• Acceptance Testing & Commissioning• Commercial Launch AVIAT NETWORKS
  26. 26. When the network is built…then what?Focus on what you do best and let Microwave experts keep thenetwork running at optimal speed and efficiency Peace of Mind! AVIAT NETWORKS
  27. 27. AVIAT NETWORKS
  28. 28. MAXIMIZE PROFITABILITY OF THE NETWORK Functional, viable, practical. ??? AVIAT NETWORKS
  29. 29. THANK YOUAVIATNETWORKS.COM

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