Wireless communication & adhoc networks

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Wireless communication & adhoc networks

  1. 1. Wireless Communications & Adhoc Networks<br />Jokhio Sultan Salahuddin Kohistani<br />07CS24<br />Computer Communication <br />& Network Management<br />Department of Computer Systems Engineering<br />MUET Jamshoro<br />
  2. 2. Agenda<br />Wireless Communications<br />Introduction<br />Generations of Wireless Communications<br />EM spectrum<br />Modes/Types<br />Wireless Computer Networks<br />Techniques<br />Security<br />Ad hoc Networks<br />Contents<br />
  3. 3. Wireless Communication  Wireless Computer Networks Wireless LANs Spread Spectrum LANs  IEEE 802.11 Architecture Specification Standard<br />Adhoc Networks<br />AGENDA<br />
  4. 4. Wireless <br />Without wires or without physical conducting material or carrier.<br />Unguided Medium<br />Communication<br />Information propagation from source to destination.<br />Hence, Wireless Communication;<br />Transfer of information over a distance without utilizing electrical conductors or "wires".<br />Wireless Communications (Introduction)<br />
  5. 5. Wireless Communications (Generations)<br />
  6. 6. Wireless Communications (Generations)<br />
  7. 7. Wireless Communications (4Generation)<br />
  8. 8. Wireless Communications (Electromagnetic Spectrum)<br />
  9. 9. Far Distant (Larger Range) Communication<br />Cellular/Mobile Communications<br />Wireless Computer Networks<br />Radar Communication<br />Satellite Communication<br />Broadcasting (Analog/Digital)<br />TVs<br />Radios<br />Wireless Communications (Modes/Types)<br />
  10. 10. Near (Shorter Distance) Communication<br />Bluetooth<br />Infrared<br />Wireless Communications (Modes/Types)<br />
  11. 11. Wireless Local Area Networks (WLANs)<br />Wireless Wide Area Networks (WWANs)<br />Wireless Communications (Computer Networks)<br />
  12. 12. A LAN with every end device/node having wireless access to share hardware, software and other devices and Resources.<br />Wireless Communications (Computer Networks: WLANs)<br />other devices<br />
  13. 13. Infrared (IR) LANs<br />Spread Spectrum LANs<br />Wireless Communications (Computer Networks: WLANs: Transmission Techniques)<br />
  14. 14. Limited to single room<br />b/c waves does not penetrate opaque walls<br />GHz to 400 THz<br />Excellent potential for data transmission<br />Keyboard, mouse, Printers, and end devices can communicate<br />Original standard data rate of 75 kbps for a distance up to 8 m. <br />The recent standard defines a data rate of 4 Mbps.<br />Wireless Communications (Computer Networks: WLANs: Transmission Techniques: Infrared LANs)<br />
  15. 15. IEEE 802.11 committee Standards<br />Makes use of Spread Spectrum transmission techniques.<br />Most Popular type of WLAN<br />Usable without having to go to licensing procedure<br />Operates in ISM [Industrial, Scientific, and Medical {902-928MHz (915MHz), 2.4-2.4835GHz (2.4GHz), 5.725-5.825GHz(5.8GHz)}] microwave band.<br />Higher the frequency, Higher the potential Bandwidth.<br />Wireless Communications (Computer NWs: WLANs: Transmission Techniques: Spread Spectrum LANs)<br />
  16. 16. Wireless Communications (Computer NWs : : : IEEE 802.11 Standard)<br />
  17. 17. Access Point (AP)<br />Basic Services Set (BSS)<br />Coordination Function<br />Distribution System<br />Extended Services Set (ESS)<br />MAC protocol data Unit (MPDU)<br />MAC service Data Unit (MSDU)<br />Station/Node/End Device<br />Wireless Communications (Computer NWs : : : IEEE 802.11 Components)<br />
  18. 18. Access Point (AP)<br />Also called Wireless Access point (WAP) or central Base Station.<br />a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth or related standards.<br />WAP or AP connects to router or any other Layer 3 device<br />Can perform switching function b/w wireless devices<br />Wired devices can also be connected to it<br />Wireless Communications (Computer NWs : : : : Access Point)<br />
  19. 19. Wireless Communications (Computer NWs : : : : Access Point)<br />A typical Wireless Access Point<br />
  20. 20. Basic Services Set (BSS)<br />Building block of a wireless LAN.<br />is made of stationary or mobile wireless stations and an optional central base station, also known as the access point (AP).<br />*A BSS without an AP is called an ad hoc network<br />ABSS with an AP is called an infrastructure network.<br />Wireless Communications (Computer NWs : : : : Basic Services Set)<br />
  21. 21. Access Point is Optional<br />Without Access point stations still can communication<br />Wireless Communications (Computer NWs : : : : Basic Services Set)<br />
  22. 22. Coordination Function<br />logical function<br />Uses CSMA techniques with CA<br />Determines when a station is permitted to transmit<br />and may able to receive the PDU.<br />Distribution Function<br />A system used to interconnect <br />A set of BSSs<br />& integrated LAN to create ESS<br />Wireless Communications (Computer NWs : : : : Coordination and Distribution Function)<br />
  23. 23. An Extended service set (ESS) <br />is made up of two or more BSSs with APs. In this case, the BSSs are connected through a distribution system, which is usually a wired LAN. <br />The distribution system connects the APs in the BSSs. <br />IEEE 802.11 does not restrict the distribution system; <br />it can be any IEEE LAN such as an Ethernet.<br />Wireless Communications (Computer NWs : : : : Extended Services set)<br />
  24. 24. MAC Protocol Data Unit (MPDU)<br />The unit of data exchanged b/w two peer MAC entities using the services of the physical layer.<br />MAC Protocol Data Unit (MSDU) <br />Information that is delivered to the user.<br />Stations <br />Any device that contains an IEEE 802.11 conformant MAC and Physical layer.<br />Wireless Communications (Computer NWs : : : : MPDU, MSDU & Stations)<br />
  25. 25. Wireless Communications (Computer NWs : : : : Collecting All)<br />ESS<br />IEEE 802.11x LAN<br />
  26. 26. Wireless Communications (Computer NWs : : : : CSMA/CA)<br />ESS<br />Carrier Sense Multiple Access with Collision Avoidance CSMA/CA<br />
  27. 27. Increase in Portable Devices<br />Simplicity and Flexibility<br />Reliable and Secure<br />Higher Data Rates, Speed and Reach<br />Technology <br />Cost Savings<br />Trend<br />Wireless Communications (Computer NWs : : : : Why Wireless..?)<br />
  28. 28. Data less secure<br />The waves could be damaging to our health<br />Modulation technique required for efficient transmission.<br />Wireless Communications (Computer NWs : : : : Why not Wireless)<br />
  29. 29. Authentication<br />A function that determines whether a Station is allowed to participate in network communication.<br />Implementing network encryption<br />Security Protocols<br />WEP (Wireless Equivalency protocol)<br />WPA (Wireless Protected Access)<br />Wireless Communications (Security)<br />
  30. 30. Data is In Air<br />Even with Encryption creative minded hackers can sniff your data and corporate confidential information.<br />Even with encryption, the data between client and AP’s are available for anyone to capture.<br />Danger for Humanity…<br />Wireless Communications (Issues)<br />
  31. 31. An Adhoc network is a peer-to-peer network (no central device) set up temporarily to meet some immediate needs.<br />When all station are mobile stations, with no connection to other BSSs, the BS is called IBSS(Independent BSS), some times referred as Ad hoc network…<br />In simple words, it is decentralized network…<br />Wireless Communications (Adhoc Networks)<br />
  32. 32. Wireless Communications (Adhoc Networks)<br />
  33. 33. For Me & rest of the class, Are you feeling like it after all..?<br />
  34. 34. Welcome Questions!<br />The End (Thanks for bearing me!)<br />?<br />
  35. 35. The World Wide web (Internet)<br />Wikipedia-The Free Encyclopedia<br />http://www.wikipedia.org/en<br />IEEE<br />http://www.ieee.org<br />ACM<br />http://www.acm.org<br />Books<br />Computer Networks<br />Tanebaum S. Andrew 4th ed.<br />Data Communications and Networking<br />Forozon A. Behrouz 4th ed.<br />Data and Computer Communications<br />Stallings William 6th ed.<br />References<br />
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