1. Wireless and Mobile Computing Sajjad Ali Mushtaq

2. What is Wireless Communication ? Transmitting voice, data, video and other services data using electromagnetic waves in open space (atmosphere) Electromagnetic waves Travel at speed of light (c = 3x10 8 m/s) Has a frequency (f) and wavelength (  ) c = f x  Where c = wave speed Higher frequency means higher energy The higher the energy the more penetrating are the radiations 2

3. Types of Wireless Communication Celullar Wireless computer network Radio service 3

4. Multiservice Point-to-Multipoint Wireless Network 4

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6. Electromagnetic Radiation Spectrum 6 The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.

7. Wavelength of Some Technologies GSM Phones: frequency ~= 900 Mhz wavelength ~= 33cm PCS Phones frequency ~= 1.8 Ghz wavelength ~= 17.5 cm Bluetooth: frequency ~= 2.4Gz wavelength ~= 12.5cm 7

8. Wireless Media Standards 8

9. Types of Electromagnetic Carriers When the distance between the sender and receiver is short (e.g. TV box and a remote control) infrared waves are used For long range distances between sender and receiver (e.g. TV broadcasting and cellular service) both microwaves and radio waves are used radio waves are ideal when large areas need to be covered and obstacles exist in the transmission path microwaves are good when large areas need to be covered and no obstacles exist in the transmission path 9

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11. Wireless Applications (Services) 11

12. Advantages and Disadvantages of Wireless Communication advantages: mobility a wireless communication network is a solution in areas where cables are impossible to install (e.g. hazardous areas, long distances etc.) easier to maintain disadvantages: has security vulnerabilities high costs for setting the infrastructure unlike wired comm., wireless comm. is influenced by physical obstructions, climatic conditions, interference from other wireless devices 12

13. Wireless Systems: Range Comparison Satellite Links SW Radio MW Radio FM Radio Mobile Telephony WLANs Blueooth 1,000 Km100 Km10 Km1 Km100 m10 m1 m 13

14. Wireless Revolution Cellular is the fastest growing sector of communication industry (exponential growth since 1982, Four generations of wireless (5G is on its way) First Generation (1G): Analog 25 or 30 KHz FM, voice only, mostly vehicular communication Second Generation (2G): Narrowband TDMA and CDMA, voice and low bit-rate data, portable units. 2.5G increased data transmission capabilities Third Generation (3G): Wideband TDMA and CDMA, voice and high bit- rate data, portable units 4G/5G 14

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16. THE RADIO PATENTS Tesla filed his basic radio patent applications in 1897. They were granted in 1900. Marconi's first patent application in America, filed on November 10, 1900, was turned down. Marconi's revised applications over the next three years were repeatedly rejected because of the priority of Tesla and other inventors. 16

17. PATENTS 17

18. Magnifying Transmitter What was Magnified? 18

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20. History: Historical Overview It Started with the Telegraph... “We call the electric telegraph the most perfect invention of modern times... as anything more perfect than this is scarcely conceivable, and we really begin to wonder what will be left for the next generation…” An electrical telegraph is a telegraphy that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages. 20

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22. Critical Attributes of Telecommunications Systems Speed Ability to transmit information in real-time Electronic transmission: faster than transportation Coverage Beyond regional: national and international in scale Metcalf’s Law: the more connected, the more useful Reliability Cost Security Transmitted information as knowledge, news, secrets Always an element of government oversight and control 22

23. Origins of Coded Transmission 1793, Revolutionary France Aerial Telegraph, invented by Claude Chappe Extensive network throughout France 1840s, Samuel F. B. Morse Coded transmission via electronic means Rapidly spread throughout US and Europe International Telegraph Union (ITU) formed in 1865 23

24. Submarine Telegraphy: High Tech of the late 19th Century 1850: Dover-to-Calais, first submarine line 1858: First transatlantic cable Breaks after 3 months! 1866: Relaid with higher quality cable Development of cable materials, technology of laying, repair Typical “Performance”: 1870: London to Bombay in 4 minutes, 22 seconds 1901: London to British Guiana, 22 minutes 1924: Telegram around the world in 80 seconds 24

25. Radio Telegraphy (also know as “Wireless”) Radio technology Communicate with ships and other moving vehicles Messages sprayed into the “ether” crossing boundaries Downfall of the nationally supported monopolistic telegraph companies 1896: Guglielmo Marconi First demonstration of wireless telegraphy Built on work of Maxwell and Hertz to send and receive Morse Code Based on long wave (>> 1 km), spark transmitter technology, requiring very large, high power transmitters First used by British Army and Navy in the Boer War 25

26. Wireless 1907: Commercial Trans-Atlantic Wireless Service Huge ground stations: 30 x 100m antenna masts Beginning of the end for cable-based telegraphy WW I: Rapid development of communications intelligence, intercept technology, cryptography 1920: Marconi discovers shortwave (<100 m) radio Longwave follow contour of land Very high transmit power, 200 KW+ Shortwaves reflect, refract, and absorb, like light Bounce off ionosphere Higher frequencies made possible by vacuum tube (1906) Cheaper, smaller, better quality transmitters 26

27. Broadband Wireless Technology Higher data rates obtainable with broadband wireless technology Graphics, video, audio Shares same advantages of all wireless services: convenience and reduced cost Service can be deployed faster than fixed service No cost of cable plant Service is mobile, deployed almost anywhere 27

28. Limitations and Difficulties of Wireless Technologies Wireless is convenient and less expensive Limitations and political and technical difficulties inhibit wireless technologies Lack of an industry-wide standard Device limitations E.g., small LCD on a mobile telephone can only displaying a few lines of text E.g., browsers of most mobile wireless devices use wireless markup language (WML) instead of HTML 28

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30. Wireless Networks Compared to Fixed Networks Higher loss-rates due to interference other EM signals, objects in path (multi-path, scattering) Limited availability of useful spectrum frequencies have to be coordinated, useful frequencies are almost all occupied Low transmission rates Higher delays, higher jitter connection setup time for cellular in the second range, several hundred milliseconds for wireless LAN systems Lower security, simpler active attacking radio interface accessible for everyone base station can be simulated, thus attracting calls from mobile phones Always shared medium secure access mechanisms important 30

31. Shifting Trends 31

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33. Impressive Wireless Infrastructure! Satellite Macro-Cell Micro-Cell Urban In-Building Pico-Cell Global Suburban dik © In-Room (BlueTooth) 33

34. Wireless Network Overlay Satellite Macro-Cell Micro-Cell Urban In-Building Pico-Cell Global Suburban dik © 34

35. GSM Base Stations in Europe Nokia PrimeSite Ericsson RBS 2000 September 1997 35

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37. Design Challenges Hardware Design Precise components Small, lightweight, low power Cheap High frequency operations System Design Converting and transferring information High data rates Robust to noise and interference Supports many users Network Design Connectivity and high speed Energy and delay constrains 37

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39. Text Book WIRELESS COMMUNICATIONS AND NETWORKS By William Stallings 2 nd Edition 39

40. Transmission Fundamentals Signals for Conveying Information Relationship between Data Rate and Bandwidth Analog and Digital Data Transmission Analog and Digital Data Analog and Digital Signaling Analog and Digital Transmission Channel Capacity Nyquist Bandwidth Shannon Capacity Formula 40

41. Transmission Media Transmission media Transmission media classification Transmission Media characteristics and design specifications Guided and Unguided media Wireless Transmission Frequencies Antennas Wireless Propagation 41

42. Wireless Transmission Wireless Transmission Examples terrestrial microwave satellite microwave broadcast radio Infrared Wireless Transmission Systems Comparison Wireless Propagation Modes Multiplexing TDM, FDM WDM 42

43. Communication Networks Comparison of basic communication network technologies Circuit switching Packet switching Frame relay ATM 43

44. Protocols and the TCP/IP Protocol Suite Requirement of Protocol Why Layered Approach is Adopted Key Features of a Protocol Simple Protocol Architecture Addressing TCP/IP and OSI model General Networking Terminology 44

45. Wireless Communication Technology Underlying technology of wireless transmission Encoding of analog and digital data for wireless transmission 45

46. Antennas and Propagation Principles of radio and microwave Antenna performance Wireless transmission modes Fading 46

47. Antennas and Propagation Electric and Magnetic Field Coupling EM Radiations Period, Frequency, and Wavelength Phase Lag and Phase Lead Antennas Why??? Antenna Analogy Why Separate TX and RX Antennas Transmission are Required Transmission Line as an Antenna Working of an Antenna Far And Near Fields Antennas Characteristics Polarization Antenna and Wavelength Antenna Gain Antenna Length 47

48. Signal Encoding Techniques Wireless transmission Analog and digital data Analog and digital signals Signal encoding techniques digital data, digital signal NRZ, multilevel binary, biphase, modulation rate analog data, digital signal PCM, DM digital data, analog signal ASK, FSK, BFSK, PSK analog data, analog signal AM, FM, PM 48

49. Spread Spectrum Frequency Hopping Direct Sequence Spread Spectrum (DSSS) Code Division Multiple Access (CDMA) 49

50. Coding and Error Control Forward Error Correction (FEC) Using redundancy for error detection Automatic Repeat Request (ARQ) techniques 50

51. Satellite Communications Geostationary satellites (GEOS) Low-earth orbiting satellites (LEOS) Medium-earth orbiting satellites (MEOS) Capacity allocation 51

52. Cellular Wireless Networks Cellular wireless network design issues First generation analog (traditional mobile telephony service) Second generation digital cellular networks Time-division multiple access (TDMA) Code-division multiple access (CDMA) Third generation networks Fourth generation networks 52

53. GSM Global System for Mobile Communication Digital Transmission ISDN compatibility Worldwide roaming in other GSM networks Provides a model for 3G Cellular systems (UMTS) 53

54. Network Simulator 2 ns -2 stands for Network Simulator version 2. ns -2: Is a discrete event simulator for networking research Work at packet level. Provide substantial support to simulate bunch of protocols like TCP, UDP, FTP, HTTP and DSR. Simulate wired and wireless network. Is primarily Unix based but can also be used with Windows via Cygwin. Use TCL as its scripting language. ns -2 is a standard experiment environment in research community. NS2 is also being used for Network on Chip Simulations e.g. flit arrival rate, latency, jitter evaluation and topology comparison 54

55. Software Defined Radios Application of Learned Concepts Application of most of the concepts A Software Defined Radio (SDR) is a system where components that have been typically implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, etc.) are instead implemented by means of software on a personal computer or embedded system. 55

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57. Thank You 57