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Wireless Communication Basics

Wireless Communication Basics. Transmitter. Receiver. RF Basics. Basic Communication System Transmitter and Receiver. Transmitter. Antenna 1. Receiver. RF Basics. Basic Communication System Transmitter and Receiver Transmitting Antenna. Transmitter. Antenna 1. Antenna 2. Receiver.

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Wireless Communication Basics

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  1. Wireless Communication Basics

  2. Transmitter Receiver RF Basics • Basic Communication System • Transmitter and Receiver

  3. Transmitter Antenna 1 Receiver RF Basics Basic Communication System • Transmitter and Receiver • Transmitting Antenna

  4. Transmitter Antenna 1 Antenna 2 Receiver RF Basics Basic Communication System • Transmitter and Receiver • Transmitting Antenna • Receiving Antenna

  5. Transmitter Antenna 1 Antenna 2 Receiver RF Basics Basic Communication System • Transmitter and Receiver • Transmitting Antenna • Receiving Antenna • Environment Environment

  6. Transmitter Antenna 1 Antenna 2 Receiver RF Basics Maximizing Range

  7. Increase Power Antenna 1 Antenna 2 Receiver RF Essentials Maximizing Range • Increase Transmitter (TX) Power • Government Regulated • Low-powered Applications

  8. Increase Power Increase Gain Increase Gain Improve RX Sensitivity RF Essentials Maximizing Range • Increase Transmitter (TX) Power • Increase Receiver (RX) Sensitivity • Specified in dBm • Every 6 dB doubles the range LOS • Every 12 dB doubles range indoors / urban environments

  9. Increase Power Increase Gain Increase Gain Improve RX Sensitivity RF Basics Maximizing Range • Increase Transmitter (TX) Power • Increase Receiver (RX) Sensitivity • Increase Antenna Gain • More gain equates with more focusing of energy • Antenna cables should be as short as possible

  10. RF Basics Basic Communication System • Transmitter and Receiver • Transmitting Antenna • Focused energy

  11. RF Basics Basic Communication System • Transmitter and Receiver • Transmitting Antenna • Receiving Antenna • Focused energy

  12. RF Basics Antenna Gain • Government-imposed power restrictions • Omnidirectional

  13. RF Basics Antenna Gain • Directional

  14. Increase Power Increase Gain Increase Gain Improve RX Sensitivity RF Basics Maximizing Range • Increase Transmitter (TX) Power • Improve Receiver (RX) Sensitivity • Increase Antenna Gain • Clear the Environment of obstructions • Visual (Linear) line-of-sight vs. RF (Radio) line-of-sight Clear the Environment

  15. Fresnel Zone RF Basics Fresnel Zone • Football-shaped path

  16. RF Basics Fresnel Zone • Football-shaped path • Acceptable = 60% of Zone 1 + 3 meters • Raise antennas to help clear the zone

  17. RF Basics Fresnel Zone • Football-shaped path • Acceptable = 60% of Zone 1 + 3 meters • Raise antennas to help clear the zone • Formula

  18. RF Basics Fresnel Zone Diameters

  19. Importance of Frequency Selection Geographic Deployment Worldwide versus Regional RF Performance Range RF Penetration Antenna Considerations

  20. License-Free Bands 2.4 GHz 315 MHz 420 MHz 900 MHz 5.7 GHz 433 MHz 868 MHz 5.7 GHz 900 MHz 433 MHz 915 MHz

  21. Regulatory Bodies FCC (United States) IC (Canada) ETSI (Europe, some APAC) C-Tick (Australia Telec (Japan) Anatel (Brazil)

  22. Rates and Ranges Wireless Video Applications Faster Video UWB Data Wireless Data Applications 802.11g 802.11a IrDA Wi-Fi® Voice Peak Data Rate 802.11b Cellular 2.5G/3G Bluetooth™ Monitoring & Control Data Transfer ZigBee™ Slower Wireless Networking Closer Farther Range

  23. Nodes Nodes and Rates

  24. Radio Modem Operation • Modem • Modulate / Demodulate

  25. Modulation What is modulation? • The process by which a parameter (amplitude, frequency or phase of a sinusoidal signal) of a higher frequency carrier wave is altered in accordance with the baseband message signal. • Transforms the message signal into a form that is suitable for transmission over the channel. • The transmitter uses the baseband message signal to modulate a carrier and transmit it over the channel.

  26. Radio Modem Operation Two types of spread spectrum used in modern Radios • FHSS- Frequency Hopping Spread Spectrum • Transmitter rapidly hops from one channel to the next in a pseudo-random fashion, avoiding long-term interference. • Receiver follows transmitter • Some Digi Products use FHSS • 24XStream 2400 2480

  27. XStreamKey Features • Price-to-Performance Value • High Receiver Sensitivity • Low Power Consumption • FCC (U.S.A.), IC (Canada), • ETSI (Europe) Approved Best Value OEM RF Modules 2.4GHz

  28. XStream (2.4 GHz)Best Value OEM RF Modules Interface Packages Available

  29. Radio Modem Operation Two types of spread spectrum used in modern Radios • DSSS- Direct Sequence Spread Spectrum • Each bit is represented by N, shorter segments, called chips. • Increases over-the-air rate by a factor of N, widening the spectrum • Correlator in receiver examines the chips and maps chips back to bits, while simultaneously spreading undesired signals • Processing gain, 10*log(chip_rate/bit_rate) • Some Digi productsuse DSSS • XBee • XBee-Pro • All WiFi enabledproducts

  30. Digi RF Products Modules (Embedded) Packaged (Boxed)

  31. DigiRF Products • XBee • XStream • XTend • XPress • XCite • Digi Mesh

  32. Digi RF Modules

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