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Wireless Technology

Wireless Technology. Wireless Media. Referred to as unbounded media. Wireless Media. Spread throughout atmosphere. Wireless Media. Not limited to a single path. Electromagnetic Waves. Categorized according to frequency ranges Frequency is based on repeating pattern of waveform

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Wireless Technology

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  1. Wireless Technology

  2. Wireless Media Referred to as unbounded media

  3. Wireless Media Spread throughout atmosphere

  4. Wireless Media Not limited to a single path

  5. Electromagnetic Waves Categorized according to frequency ranges Frequency is based on repeating pattern of waveform One complete waveform is a cycle Frequency is the number of times a cycle occurs in one second

  6. Radio and Microwave Transmission (Cont.) Demodulation occurs after carrier wave and voice wave are received Channel is identified by the assigned frequency

  7. Infrared Transmission • Uses a series of digital light pulses • Television remote control • Personal digital assistants • Laptops • Disadvantages • Devices must be in direct line of sight of each other • Can be used only for short distances

  8. Radio Interference • Can be caused by: • Virtually any type of electrical equipment • Faulty electrical equipment • Close proximity • A powerful signal • Industrial, Scientific, and Medical (ISM) band

  9. ISM Band

  10. Signal Reflection A reflected radio signal can combine with the intended radio signal and either disrupt the intended signal or enhance it

  11. Antenna Styles The two major classifications are omni-directional and directional

  12. Antenna Styles (Cont.)

  13. Radio Waves and Networks Radio waves used in LANs Adhere to IEEE 802.11 and Bluetooth standards Operate at 2.4GHz

  14. Radio Wave-Based Transmission Techniques • Spread spectrum refers to transmission channels spread across the spectrum of available bandwidth • Frequency hopping – data that is transmitted simultaneously on multiple channels • Direct sequencingdata that is transmitted sequentiallyon multiple channels • Orthogonal frequency-division multiplexing (OFDM) communicates wireless data over several different channels within an assigned frequency range

  15. Frequency Hopping Spread Spectrum (FHSS)

  16. Direct Sequencing Spread Spectrum (DSSS)

  17. Orthogonal Frequency-Division Multiplexing (OFDM)

  18. FCC U-NII Classifications FCC divided the 5 GHz radio frequency into three, 20-MHz channels called the Unlicensed National Information (U-NII) Infrastructure Each U-NII classification has a frequency range of 100 MHz

  19. Radio Wave-Based Networking Wireless Access Point (WAP) provides access to hardwired devices such as printers and routers WAP controls flow of communication All WAPs use same Service Set Identifier (SSID) SSIDs should be changed to enhance security

  20. Wireless Network Modes Infrastructure mode Ad hoc mode IEEE 802.11 Standard uses terms Basic Service Set (BSS) and Independent Basic Service Set (IBSS) Extended Service Set Identifier (ESSID) allows user to keep connection while moving around the location Devices need to be Wi-Fi compliant

  21. IEEE 802.11 Standards

  22. Applied Networking You are replacing a dead 802.11g WAP in an existing wireless network with an 802.11n WAP. Three laptops connect to this network. Two have 802.11n wireless adapters, and one has an 802.11g adapter. What will the maximum data rate be when the 802.11n WAP is installed?

  23. 802.11n Latest 802.11 wireless network topology Multiple Input Multiple Output (MIMO) MIMO increases data transmission rate by using spatial multiplexing Prior to MIMO, WAPs sent single stream of data between transmitter and receiver

  24. CSMA/CA Process

  25. Overlap Area Ad-hoc overlap area Infrastructure mode overlap area

  26. Extending Wireless Network Range with WAPs

  27. Extending Wireless Network Range with Cabling

  28. Applied Networking You’ve been asked to create an Extended Service Set (ESSID) from two existing 802.11 g wireless networks. However, the two WAPs (one from each network) are about 75 meters apart. How can you extend the range without adding another WAP?

  29. New IEEE Wireless Standards • Working group—Standards that are still under development • Also known as Wireless Personal Network (WPAN) • IEEE 802.16 is working group hoping to: • Achieve data rates as high as 70 Mbps over distances of 30 miles or more • Expand the radio frequencies assigned by the FCC

  30. New IEEE Wireless Standards (Cont.) • Wireless USB connects devices wirelessly to transfer data between a PC and devices such as cameras, printers, and mobile phones, among others • Bluetooth, or piconet • Short-range wireless system designed for limited distances • Does not interfere with 802.11b devices

  31. Cellular Technology Device connects to radio transmitter/receiver within its cell Communicates to remote cells via microwaves Responsible for wireless telephone technology Connects mobile and stationary computer equipment

  32. PC to Mobile Network Device Cellular Communication

  33. Microwave Transmission and Networking Microwave describes radio waves in the electromagnetic spectrum Higher radio wave frequency=more data transmitted Satellite travels in a geosynchronous orbit Significant disadvantage of satellite communications is propagation delay

  34. Satellite System

  35. Wireless Technology

  36. Wireless Security • IEEE 802.1x draft standard for wireless network • Extensible Authentication Protocol (EAP) uses exchange of username and password • PEAP is improved version of EAP • Wired Equivalent Privacy (WEP) uses encryption keys to secure data sent over wireless networks

  37. Wireless Security (Cont.) • Wi-Fi Protected Access (WPA) • WPA-PSK is variation of WPA • WPA-2 is improved version of WPA • Wireless Application Protocol (WAP) combines authentication and encryption

  38. IEEE 802.1x Authentication and Encryption Protocols

  39. Windows XP WLAN Properties

  40. Windows Vista Wireless Network Properties

  41. Applied Networking When configuring a Wireless Access Point for a home network, the installation program prompts you for a security type. The choices are WPA2-Enterprise, WPA-Personal, and WEP-128. Which security type would be the most appropriate for the given wireless network, while providing the highest level of security?

  42. Review Radio wave and microwave transmission use a _____ to carry data. carrier wave

  43. Review Which of the following does not describe a carrier wave? A. Identified by a frequency number B. Mixed with a data signal C. Consist of a varying frequency D. Is a set frequency C. Consist of a varying frequency

  44. Review A simple radio transmission consists of a _____ and _____. transmitter, receiver

  45. Review The _____ produces the carrier wave and modulates the data signal into the carrier wave. transmitter

  46. Review The _____ receives the modulated wave and demodulates it. receiver

  47. Review The bandwidth of a carrier wave is referred to as a(n) _____. channel

  48. Review A radio station number, such as 104.5, is referred to as a(n) _____. channel

  49. Review A(n) _____ type antenna transmits radio signals in all directions. A. Dipole B. Omni C. Parabolic D. Yagi B. Omni

  50. Review The _____ type antenna is typically used as a client or receiver. A. Dipole B. Omni C. Parabolic D. Yagi A. Dipole

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