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Basic concepts of wireless communication system


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Basic concepts of wireless communication system

  1. 1. Basic Concepts of WirelessCommunication SystemPrepared by: Mr. Gilbert De Castro
  2. 2.  Computer Networking Data Communication Transmission Media Distributed SystemObjectives
  3. 3. Basic Principle of NetworksComputer network Collection of computersand devices connectedvia communicationsdevices andtransmissionmedia Bunch of computershook together in someway Each particular messageis usually routed to aparticular computer
  4. 4. Basic Principle of NetworksNetworking Is the problem ofdelivering a messagefrom a source to adestination The problem of givingmeaning to thesemessages received iscalled communication
  5. 5. Use of Computer Networks Networks for Companies Resource sharing – Saves time and money. Dynamic rerouting – Having alternative source of supplydataBasic Principle of Networks
  6. 6.  Networks for people Access to remote information – Great source ofinformation Person-to-person communication Interaction between a person and a database Person-to-person interaction Interactive entertainment Network gaming Video-on-demandBasic Principle of Networks
  7. 7. Advantages of networking Connectivity and communication Data sharing Hardware sharing Internet access Internet access sharing Data security and management Performance enhancement and balancing EntertainmentBasic Principle of Networks
  8. 8. Basic Principle of NetworksCommunication channel Is a pathway over whichinformation can betransferred Information sent over achannel has source (oftencalled the transmitter), fromwhich the informationoriginates And destination (often calledthe receiver), to which theinformation is deliveredChannel
  9. 9. Communication channelsAny communication has a direction associated with it Simplex channel – is a channel whose direction oftransmission is unchanging Half-duplex channel – is a channel in which thedirection may be reversed, but the transmission doesnot occur at the same time Full-duplex channel – is a channel that allowssimultaneous exchange in both directionsBasic Principle of Networks
  10. 10. Types of Transmission Technologies Point-to-point network – consist of many connectionsto individual pairs of machines Broadcast networks – all the machines on thenetwork share a single channelBasic Principle of Networks
  11. 11. Network Topologies Computer networks come in different shapes andsizes The network’s topology can be thought of as its“shape”, the way the computers on the network areconnected Network topologies are categorized into the fivebasic typesBasic Principle of Networks
  12. 12. Characteristics of effective data communication Delivery Accuracy TimelinessBasic Principle of Networks
  13. 13. Components of data communication Message Sender Receiver Medium ProtocolsBasic Principle of Networks
  14. 14. Protocol Formal description of set of rule sand conventionsthat govern how devices on a network communicate Control aspects of data communication, whichinclude the following: How the physical data is built How computers connect to the network How the data is formatted for transmission How the data is sent How to deal with errors
  15. 15. Basic Principle of NetworksNetwork TopologiesBus network A common channelconnect all devices All computers anddevices connect tocentral cable, or bus
  16. 16. Basic Principle of NetworksRing network All messages travel in a ring,either in clockwise orcounterclockwise direction Cable forms closed ring, orloop, with all computers anddevices arranged along ring Data travels from device todevice around entire ring, inone direction
  17. 17. Basic Principle of NetworksStar network All devices connect to acentral device, called hub All data transferred fromone computer to anotherpasses through hub
  18. 18. Basic Principle of Networks Tree network -Integrates multiple startopologies together intoa bus
  19. 19. Basic Principle of Networks Mesh network – involvesthe concept of routes,where a message is senton the network can takeany of several possiblepaths from source todestination Popular topologies arebus, ring, and star
  20. 20. Communications device Hardware component that enables a computer tosend and receive data, instructions and information Occurs over cables, telephone lines, cellular radionetworks, satellites, and other transmission media
  21. 21. Communication Devices Modem Network Card Gateway Router Wireless Access Point Hub
  22. 22. Modem• Converts digital signals to analog signals and vice versa Dial up modem ISDN and DSL modems Wireless modem
  23. 23. Network Card Adapter card, PC Card, or flash card that enablescomputer or device to access network Sometimes called network interface card (NIC)
  24. 24. Gateway Links network using different protocols Contain devices such as protocol translators
  25. 25. Router Connects multiple networks and determines thefastest route for sending data over the network
  26. 26. Wireless Access Point Connects wireless communication devices
  27. 27. Hub• Device that provides central point for cables innetwork
  28. 28. Communication Channel Transmission media on which data travels incommunications system Transmission media - are materials capable of carryingone or more signals Bandwidth - amount of data that can travel over acommunications channel Physical Transmission Media Wireless Transmission Media
  29. 29. Physical Transmission Media Wire, cable, and other tangible materials usedto send communications signals Twisted-pair cable Coaxial Cable Fiber-optic cable
  30. 30. Twisted-pair cable Used for telephone systems and network cabling
  31. 31. Coaxial Cable Often used for cable television wiring
  32. 32. Fiber-optic cable Capable of carryingsignificantly moredata at faster speeds thanwire cables Less susceptible tointerference (noise) and,therefore, more secure,Smaller size (thinner andlighter)
  33. 33. Wireless transmission media Radio Signal Microwaves Satellites IrDA Bluetooth Wi-Fi
  34. 34. Radio Signal Broadcast radio distributesradio signals over long andshort distances Cellular radio is form ofbroadcast radio used formobile communications
  35. 35. Microwaves Earth-based reflectivedish used for microwavecommunications Must transmit in straightline with no obstructions
  36. 36. Satellites Space stationthat receives microwavesignals from earth-basedstation, amplifies signals,and broadcasts signals backto any number of earth-based stations
  37. 37. IrDA ( Infrared Data Association) Physical specifications communications protocolstandards for the short-range exchange of data overinfrared light waves
  38. 38. Bluetooth Short-range radio waves transmit data betweenBluetooth devices Short distance transmission of about 30 feet
  39. 39. Wi-Fi Wireless Fidelity Connecting electronic devices wirelessly
  40. 40. Basic Principle of NetworksDistributed Systems There is considerable confusion between a computernetwork and a distributed system The key distinction is that in a distributed system, theexistence of multiple autonomous computers istransparent to the user The user can type a command to run a program, and itruns It is up to the operating system to choose the bestprocessor for the application, send the necessary dataand place the result to the proper location
  41. 41. Basic Principle of NetworksClient/Server Extension of distributed dataprocessing wherein it providesthe best of both centralized anddistributed data processing Client – issues a request to aserver to ask for work to bedone Server – usually a host machinethat provides database,printing, storage andcommunications
  42. 42. Basic Principle of NetworksTypes of network designThe networking industry refers to nearly every type ofnetwork as an “area network”. Local Area Network (LAN) Wide Area Networks (WAN)
  43. 43. Basic Principle of NetworksLocal Area Network (LANs) Connect network devicesover relatively shortdistances Usually owned by anindividual or corporation Network in limitedgeographical area such ashome or office building
  44. 44. Basic Principle of NetworksWide Area Networks (WANs) Span a large physical distance(geographically-dispersedcollection of LANs) andmostly owned by any oneorganization but rather existunder collective or distributedownership and management Network that covers largegeographic area using manytypes of media Internet is world’s largestWAN