SlideShare a Scribd company logo

Wireless communication & adhoc networks

•Download as PPTX, PDF•
•
Salahuddin Jokhio
Salahuddin Jokhio

This document discusses wireless communications and ad hoc networks. It begins with an introduction to wireless communications, including the generations of wireless technologies and the electromagnetic spectrum used. It then covers wireless computer networks, focusing on wireless local area networks (WLANs) and describing the IEEE 802.11 standard architecture. This includes components like access points, basic service sets, and extended service sets. It also discusses security issues with wireless networks and ad hoc networks, which are decentralized peer-to-peer networks without a central access point. In the end, it provides some references for further reading on these topics.

Related slideshows

ADhoc- network overview,application,issues.
ADhoc- network overview,application,issues.ADhoc- network overview,application,issues.
ADhoc- network overview,application,issues.
 
WLAN
WLANWLAN
WLAN
 
wireless sensor network a survey
wireless sensor network a surveywireless sensor network a survey
wireless sensor network a survey
 
1 of 35
Wireless Communications & Adhoc NetworksJokhio Sultan Salahuddin Kohistani07CS24Computer Communication & Network ManagementDepartment of Computer Systems EngineeringMUET Jamshoro
AgendaWireless CommunicationsIntroductionGenerations of Wireless CommunicationsEM spectrumModes/TypesWireless Computer NetworksTechniquesSecurityAd hoc NetworksContents
Wireless Communication  Wireless Computer Networks Wireless LANs Spread Spectrum LANs  IEEE 802.11 Architecture Specification StandardAdhoc NetworksAGENDA
Wireless Without wires or without physical conducting material or carrier.Unguided MediumCommunicationInformation propagation from source to destination.Hence, Wireless Communication;Transfer of information over a distance without utilizing electrical conductors or "wires".Wireless Communications (Introduction)
Wireless Communications (Generations)
Wireless Communications (Generations)
Wireless Communications (4Generation)
Wireless Communications (Electromagnetic Spectrum)
Far Distant (Larger Range) CommunicationCellular/Mobile CommunicationsWireless Computer NetworksRadar CommunicationSatellite CommunicationBroadcasting (Analog/Digital)TVsRadiosWireless Communications (Modes/Types)
Near (Shorter Distance) CommunicationBluetoothInfraredWireless Communications (Modes/Types)
Wireless Local Area Networks (WLANs)Wireless Wide Area Networks (WWANs)Wireless Communications (Computer Networks)
A LAN with every end device/node having wireless access to share hardware, software and other devices and Resources.Wireless Communications (Computer Networks: WLANs)other devices
Infrared (IR) LANsSpread Spectrum LANsWireless Communications (Computer Networks: WLANs: Transmission Techniques)
Limited to single roomb/c waves does not penetrate opaque wallsGHz to 400 THzExcellent potential for data transmissionKeyboard, mouse, Printers, and end devices can communicateOriginal standard data rate of 75 kbps for a distance up to 8 m. The recent standard defines a data rate of 4 Mbps.Wireless Communications (Computer Networks: WLANs: Transmission Techniques: Infrared LANs)
IEEE 802.11 committee StandardsMakes use of Spread Spectrum transmission techniques.Most Popular type of WLANUsable without having to go to licensing procedureOperates in ISM [Industrial, Scientific, and Medical {902-928MHz (915MHz), 2.4-2.4835GHz (2.4GHz), 5.725-5.825GHz(5.8GHz)}] microwave band.Higher the frequency, Higher the potential Bandwidth.Wireless Communications (Computer NWs: WLANs: Transmission Techniques: Spread Spectrum LANs)
Wireless Communications (Computer NWs : : : IEEE 802.11 Standard)
Access Point (AP)Basic Services Set (BSS)Coordination FunctionDistribution SystemExtended Services Set (ESS)MAC protocol data Unit (MPDU)MAC service Data Unit (MSDU)Station/Node/End DeviceWireless Communications (Computer NWs : : : IEEE 802.11 Components)
Access Point (AP)Also called Wireless Access point (WAP) or central Base Station.a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth or related standards.WAP or AP connects to router or any other Layer 3 deviceCan perform switching function b/w wireless devicesWired devices can also be connected to itWireless Communications (Computer NWs : : : : Access Point)
Wireless Communications (Computer NWs : : : : Access Point)A typical Wireless Access Point
Basic Services Set (BSS)Building block of a wireless LAN.is made of stationary or mobile wireless stations and an optional central base station, also known as the access point (AP).*A BSS without an AP is called an ad hoc networkABSS with an AP is called an infrastructure network.Wireless Communications (Computer NWs : : : : Basic Services Set)
Access Point is OptionalWithout Access point stations still can communicationWireless Communications (Computer NWs : : : : Basic Services Set)
Coordination Functionlogical functionUses CSMA techniques with CADetermines when a station is permitted to transmitand may able to receive the PDU.Distribution FunctionA system used to interconnect A set of BSSs& integrated LAN to create ESSWireless Communications (Computer NWs : : : : Coordination and Distribution Function)
An Extended service set (ESS) 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. The distribution system connects the APs in the BSSs. IEEE 802.11 does not restrict the distribution system; it can be any IEEE LAN such as an Ethernet.Wireless Communications (Computer NWs : : : : Extended Services set)
MAC Protocol Data Unit (MPDU)The unit of data exchanged b/w two peer MAC entities using the services of the physical layer.MAC Protocol Data Unit (MSDU) Information that is delivered to the user.Stations Any device that contains an IEEE 802.11 conformant MAC and Physical layer.Wireless Communications (Computer NWs : : : : MPDU, MSDU & Stations)
Wireless Communications (Computer NWs : : : : Collecting All)ESSIEEE 802.11x LAN
Wireless Communications (Computer NWs : : : : CSMA/CA)ESSCarrier Sense Multiple Access with Collision Avoidance CSMA/CA
Increase in Portable DevicesSimplicity and FlexibilityReliable and SecureHigher Data Rates, Speed and ReachTechnology Cost SavingsTrendWireless Communications (Computer NWs : : : : Why Wireless..?)
Data less secureThe waves could be damaging to our healthModulation technique required for efficient transmission.Wireless Communications (Computer NWs : : : : Why not Wireless)
AuthenticationA function that determines whether a Station is allowed to participate in network communication.Implementing network encryptionSecurity ProtocolsWEP (Wireless Equivalency protocol)WPA (Wireless Protected Access)Wireless Communications (Security)
Data is In AirEven with Encryption creative minded hackers can sniff your data and corporate confidential information.Even with encryption, the data between client and AP’s are available for anyone to capture.Danger for Humanity…Wireless Communications (Issues)
An Adhoc network is a peer-to-peer network (no central device) set up temporarily to meet some immediate needs.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…In simple words, it is decentralized network…Wireless Communications (Adhoc Networks)
Wireless Communications (Adhoc Networks)
For Me & rest of the class, Are you feeling like it after all..?
Welcome Questions!The End (Thanks for bearing me!)?
The World Wide web (Internet)Wikipedia-The Free Encyclopediahttp://www.wikipedia.org/enIEEEhttp://www.ieee.orgACMhttp://www.acm.orgBooksComputer NetworksTanebaum S. Andrew 4th ed.Data Communications and NetworkingForozon A. Behrouz 4th ed.Data and Computer CommunicationsStallings William 6th ed.References

More Related Content

Wireless communication & adhoc networks

  • 1. Wireless Communications & Adhoc NetworksJokhio Sultan Salahuddin Kohistani07CS24Computer Communication & Network ManagementDepartment of Computer Systems EngineeringMUET Jamshoro
  • 2. AgendaWireless CommunicationsIntroductionGenerations of Wireless CommunicationsEM spectrumModes/TypesWireless Computer NetworksTechniquesSecurityAd hoc NetworksContents
  • 3. Wireless Communication  Wireless Computer Networks Wireless LANs Spread Spectrum LANs  IEEE 802.11 Architecture Specification StandardAdhoc NetworksAGENDA
  • 4. Wireless Without wires or without physical conducting material or carrier.Unguided MediumCommunicationInformation propagation from source to destination.Hence, Wireless Communication;Transfer of information over a distance without utilizing electrical conductors or "wires".Wireless Communications (Introduction)
  • 9. Far Distant (Larger Range) CommunicationCellular/Mobile CommunicationsWireless Computer NetworksRadar CommunicationSatellite CommunicationBroadcasting (Analog/Digital)TVsRadiosWireless Communications (Modes/Types)
  • 10. Near (Shorter Distance) CommunicationBluetoothInfraredWireless Communications (Modes/Types)
  • 11. Wireless Local Area Networks (WLANs)Wireless Wide Area Networks (WWANs)Wireless Communications (Computer Networks)
  • 12. A LAN with every end device/node having wireless access to share hardware, software and other devices and Resources.Wireless Communications (Computer Networks: WLANs)other devices
  • 13. Infrared (IR) LANsSpread Spectrum LANsWireless Communications (Computer Networks: WLANs: Transmission Techniques)
  • 14. Limited to single roomb/c waves does not penetrate opaque wallsGHz to 400 THzExcellent potential for data transmissionKeyboard, mouse, Printers, and end devices can communicateOriginal standard data rate of 75 kbps for a distance up to 8 m. The recent standard defines a data rate of 4 Mbps.Wireless Communications (Computer Networks: WLANs: Transmission Techniques: Infrared LANs)
  • 15. IEEE 802.11 committee StandardsMakes use of Spread Spectrum transmission techniques.Most Popular type of WLANUsable without having to go to licensing procedureOperates in ISM [Industrial, Scientific, and Medical {902-928MHz (915MHz), 2.4-2.4835GHz (2.4GHz), 5.725-5.825GHz(5.8GHz)}] microwave band.Higher the frequency, Higher the potential Bandwidth.Wireless Communications (Computer NWs: WLANs: Transmission Techniques: Spread Spectrum LANs)
  • 16. Wireless Communications (Computer NWs : : : IEEE 802.11 Standard)
  • 17. Access Point (AP)Basic Services Set (BSS)Coordination FunctionDistribution SystemExtended Services Set (ESS)MAC protocol data Unit (MPDU)MAC service Data Unit (MSDU)Station/Node/End DeviceWireless Communications (Computer NWs : : : IEEE 802.11 Components)
  • 18. Access Point (AP)Also called Wireless Access point (WAP) or central Base Station.a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth or related standards.WAP or AP connects to router or any other Layer 3 deviceCan perform switching function b/w wireless devicesWired devices can also be connected to itWireless Communications (Computer NWs : : : : Access Point)
  • 19. Wireless Communications (Computer NWs : : : : Access Point)A typical Wireless Access Point
  • 20. Basic Services Set (BSS)Building block of a wireless LAN.is made of stationary or mobile wireless stations and an optional central base station, also known as the access point (AP).*A BSS without an AP is called an ad hoc networkABSS with an AP is called an infrastructure network.Wireless Communications (Computer NWs : : : : Basic Services Set)
  • 21. Access Point is OptionalWithout Access point stations still can communicationWireless Communications (Computer NWs : : : : Basic Services Set)
  • 22. Coordination Functionlogical functionUses CSMA techniques with CADetermines when a station is permitted to transmitand may able to receive the PDU.Distribution FunctionA system used to interconnect A set of BSSs& integrated LAN to create ESSWireless Communications (Computer NWs : : : : Coordination and Distribution Function)
  • 23. An Extended service set (ESS) 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. The distribution system connects the APs in the BSSs. IEEE 802.11 does not restrict the distribution system; it can be any IEEE LAN such as an Ethernet.Wireless Communications (Computer NWs : : : : Extended Services set)
  • 24. MAC Protocol Data Unit (MPDU)The unit of data exchanged b/w two peer MAC entities using the services of the physical layer.MAC Protocol Data Unit (MSDU) Information that is delivered to the user.Stations Any device that contains an IEEE 802.11 conformant MAC and Physical layer.Wireless Communications (Computer NWs : : : : MPDU, MSDU & Stations)
  • 25. Wireless Communications (Computer NWs : : : : Collecting All)ESSIEEE 802.11x LAN
  • 26. Wireless Communications (Computer NWs : : : : CSMA/CA)ESSCarrier Sense Multiple Access with Collision Avoidance CSMA/CA
  • 27. Increase in Portable DevicesSimplicity and FlexibilityReliable and SecureHigher Data Rates, Speed and ReachTechnology Cost SavingsTrendWireless Communications (Computer NWs : : : : Why Wireless..?)
  • 28. Data less secureThe waves could be damaging to our healthModulation technique required for efficient transmission.Wireless Communications (Computer NWs : : : : Why not Wireless)
  • 29. AuthenticationA function that determines whether a Station is allowed to participate in network communication.Implementing network encryptionSecurity ProtocolsWEP (Wireless Equivalency protocol)WPA (Wireless Protected Access)Wireless Communications (Security)
  • 30. Data is In AirEven with Encryption creative minded hackers can sniff your data and corporate confidential information.Even with encryption, the data between client and AP’s are available for anyone to capture.Danger for Humanity…Wireless Communications (Issues)
  • 31. An Adhoc network is a peer-to-peer network (no central device) set up temporarily to meet some immediate needs.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…In simple words, it is decentralized network…Wireless Communications (Adhoc Networks)
  • 33. For Me & rest of the class, Are you feeling like it after all..?
  • 34. Welcome Questions!The End (Thanks for bearing me!)?
  • 35. The World Wide web (Internet)Wikipedia-The Free Encyclopediahttp://www.wikipedia.org/enIEEEhttp://www.ieee.orgACMhttp://www.acm.orgBooksComputer NetworksTanebaum S. Andrew 4th ed.Data Communications and NetworkingForozon A. Behrouz 4th ed.Data and Computer CommunicationsStallings William 6th ed.References