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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. In class lab Labsim Wireless Network Configuration 6.44 – 6.47 Next Class LabSim6.3-6.3.4, 6.4.1-6.4.3

  18. Radio Wave-Based Transmission Techniques Orthogonal frequency-division multiplexing (OFDM) communicates wireless data over several different channels within an assigned frequency range

  19. 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

  20. 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

  21. Wireless Network Modes Infrastructure mode – a wireless network that contains one or more access points Ad hoc mode – a wireless network that does not contain an access point IEEE 802.11 Standard uses terms Basic Service Set (BSS)wireless devices connected as and infrastructure / SSID Independent Basic Service Set (IBSS)direct connection between 2 wireless devices Extended Service Set Identifier (ESSID) allows user to keep connection while moving around the location Devices need to be Wi-Fi compliant

  22. IEEE 802.11 Standards

  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 Carrier sense multiple access with collision avoidance

  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. 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

  29. 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 piconeta personal network • Short-range wireless system designed for limited distances • Does not interfere with 802.11b devices

  30. Wireless Technology

  31. 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

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

  33. IEEE 802.1x Authentication and Encryption Protocols

  34. Windows Vista Wireless Network Properties

  35. Exam 4 Review 10/30/2013 Understand the concept of a carrier wave Understand the concept of infrared data transmission Understand the regulation of frequency assignments in the U.S Understand what the ISM is used for Know the various antenna styles and their uses What is frequency hopping What are the various data transmission techniques Understand how radio transmission can be sent Understand the OFDM transmission technique What is the function of a WAP Understand the frequencies of 802.11B – N and their transmission, access, and authentication methods and throughput ratings Understand the communication process of WEP Understand the communication process of WPA Know the types of wireless network systems and how they are identified Know the various types of wireless network configuration How does distance affect wireless communication Understand the concept of bit rate Know what is sampling frequency, Latency, Jitter, VOIP, QOS, Understand which protocols are used for VOIP, multimedia streaming, audio and video transmission,data delivery

  36. In class lab Roberts Lab 17 Next Class Test 4

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

  38. 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

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

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

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

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

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

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

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

  46. Review Which of the following antenna types is not used for point-to-point links. A. Flat panel B. Omni C. Parabolic D. Yagi B. Omni

  47. Review Which of the following is not a spread spectrum transmission technique? A. Direct sequencing B. Frequency hopping C. Orthogonal frequency-division multiplexing (OFDM) C. Orthogonal frequence-division multiplexing (OFDM)

  48. Review The _____ transmission technique uses multiple channels to transmit data sequentially. A. direct sequencing B. frequency hopping C. Orthogonal Frequency-Division Multiplexing A. direct sequencing

  49. Review The FCC divided the 5-GHz radio frequency into three, _____-MHz channels and classified them as the U-NII. A. 10 B. 20 C. 40 D. 60 B. 20

  50. Review Each U-NII classification has a frequency range of _____MHz A. 100 B. 200 C. 400 D. 600 A. 100

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