Communication systems


Published on

Published in: Business, Technology
1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide
  • The Radar Set AN/SPS-49 is an L-band, long-range, two-dimensional, air-search radar system that provides automatic detection and reporting of targets within its surveillance volume. The AN/SPS-49(V) radar operates in the frequency range of 850 - 942 MHZ. It shows the elevation coverage of a typical air search radar.
  • 1 1
  • It resolves in elevation as well as azimuth. It uses multiple feeds and switches between feeds for different elevation angles. It has six stacked beams.
  • Q1. Can you think of a system whose range of communication is more than satellite links? Q2. Give an example of a system whose range of communication is shorter than IR links. Point to ponder: Why does range of communication increase on logarithm scale?
  • Communication systems

    1. 1. Submitted to : Mr. Tarun Verma Submitted by : Sagar Bissa(2011uec1298) Ramniwas Jat (2011uec1296) Sandeep Kr. Mahawar(2011uec1303) Rakesh Mehra(2011uec1293) Sitaram Choudhary(2011uec1312)
    2. 2. Outline • Communication Systems • Wireless Communications • Radio • Radar • History of wireless communication • Current Wireless Systems • Cellular systems • Wireless LANs • Satellite Systems • Paging Systems • Bluetooth • Sixth sense Technology • Design challenges
    3. 3. COMMUNICATION SYSTEMS • Provide electronic exchange of multimedia data, Voice, data, video, music, email, web pages, etc. • Communication Systems of today Radio and TV broadcasting, Public Switched Telephone Network (voice, fax, modem) • Cellular Phones • Computer networks (LANs, WANs, and the Internet) • Satellite systems (pagers, voice/data, movie broadcasts) • Bluetooth
    4. 4. Block diagram of a Communication Systems Transmitter Carrier Information to be transmitted (Baseband signal) Transmitted signal Channel Received signal Receiver Recovery of information
    5. 5. Objectives • Provide electronic exchange of multimedia information • The information to be transmitted is electromagnetic wave or electrical signal may represent: multimedia data, Voice, data, video, music, email, web pages, etc. • The frequency bandwidth occupied by the information signal is called the baseband, and the signal is often referred to as the baseband signal. • Channel – is the medium by which the transmitted signal is propagated: • Various layers of atmosphere, cable for telephone or date link, cable TV or • Electrical signals are converted to a corresponding light signal that is propagated through a fiber optic channel
    6. 6. What is Wireless Communication ?  Transmitting voice and data using electromagnetic waves in open space (atmosphere) Electromagnetic wave Travel at speed of light (c = 3x108 m/s) Has a frequency (f) and wavelength (λ) c=fx λ Higher frequency means higher energy photons The higher the energy photon the more penetrating is the radiation
    7. 7. Wireless Communications • Multimedia wireless Communications at any Time and Anywhere • Brief history • Ancient Systems: Smoke Signals, Carrier Pigeons • Radio invented in the 1880s by Marconi • Many sophisticated military radio systems were developed during and after WW2 • Cellular has enjoyed exponential growth since 1988, with more than 2 billion users worldwide today • Ignited the recent wireless revolution, 1980-2003 • Growth rate tapering off • Is there a future for wireless?
    8. 8. RADIO
    9. 9. An inventor named James Clerk Maxwell was accredited for the initial discovery of the uses of radio signals. Although he did not invent the radio. Nikola Tesla was the first to talk about utilizing these signals for the use of communication.
    10. 10. Another inventor named Guglielmo Marconi built a radio system around the same period capable of spanning long distances . Many others experimented and contributed to the invention of radio including; Faraday, Bose, and Popov.
    11. 11. radio waves are generated by an antenna and they propagate in all directions as a straight line radio waves travel at a velocity of 186.000 miles per second radio waves become weaker as they travel a long distance
    12. 12. there are 3 modes of propagation:  surface mode – for low frequency waves  direct mode – for high frequency waves  ionospheric mode – long distance high frequency waves
    13. 13. ENCODING INFORMATION ON RADIO WAVES • What quantities characterize a radio wave? – sort of info it carries, frequency or type of encoding done.. • Two common ways to carry analog information with radio waves – Amplitude Modulation (AM) – Frequency Modulation (FM): “static free”
    14. 14. Radar • RADAR is a method of using electromagnetic waves to remote- sense the position, velocity and identifying characteristics of targets. Two Basic Radar Types • Pulse Transmission • Continuous Wave
    15. 15. Types of radar 1 Primary radar 2 secondary radar Pulse radar Continues radar Intra pulse modulated Pulse modulated modulate d Un modulated Imaging Radar Non-Imaging Radar
    16. 16. How pulse Radar Works
    17. 17. Frequency modulation looks like On the above diagram, the frequency of the wave is low on the left and it slowly increases as you look right. The different frequencies of the wave will lie in a range called bandwidth. Radars use bandwidth for several reasons regarding the resolution of a data image, memory of the radar and overuse of the transmitter. For instance, a high bandwidth can yield a finer resolution but take up more memory.
    18. 18. Continuous- Wave Radar CW radar sets transmit a high-frequency signal continuously. The echo signal is received and processed. The receiver need not to be mounted at the same place as the transmitter. Every firm civil radio transmitter can work as a radar transmitter at the same time, if a remote receiver compares the propagation times of the direct signal with the reflected one. Tests are known that the correct location of an airplane can be calculated from the evaluation of the signals by three different television stations.
    19. 19. Frequency Wavelength 1 mm1 km 1 m 1 µm 1 nm 1 MHz 1 GHz IR UV 109 Hz 0 1 2 3 4 5 6 7 8 9 10 11 12 30 20 10 8 6 5 4 39 7 Allocated Frequency (GHz) Wavelength (cm) X-BandC-BandS-BandL-BandUHF VHF Visible 1012 Hz Ku K Ka W
    20. 20. Radar observables: • Target range • Target angles (azimuth & elevation) • Target size (radar cross section) • Target speed (Doppler) • Target features (imaging) Antenna Transmitted Pulse Target Cross Section Propagation Reflected Pulse (“echo”)
    21. 21. Radar Range Measurement Transmitted Pulse Reflected Pulse Range Target • Target range = cτ 2 wherec = speed of light τ = round trip time
    22. 22. Use of radar  Detection and search radar  missile guidance systems  Radar for biological research  Air traffic control and navigation radar  Weather-sensing radar systems  Parking of vehicles  military purpose  electron pressure  Temperature measurement
    23. 23. Radar Can Measure Pressure The strength of the echo received from the ionosphere measures the number of electrons able to scatter radio waves or what we call electron pressure
    24. 24. Radar Can Measure Temperature Some electrons are moving due to heat - In this case the echo is scattered The echo will contain a range of frequencies close to the transmitter frequency As the temperature increases, the electrons move faster So radar can act like a thermometer and measure the temperature of the ionosphere
    25. 25. • Atmospheric attenuation • Reflection off of earth’s surface • Over-the-horizon diffraction • Atmospheric refraction Radar beams can be attenuated, reflected and bent by the environment Radar beams can be attenuated, reflected and bent by the environment
    26. 26. Atmospheric Effects
    27. 27. The AN/TPS-43 radar system, with a 200 mile range, was the only Air Force tactical ground based long range search and warning radar for nearly two decades. Most of the AN/TPS-43 radars are being modified to the AN/TPS-75 configuration. 3-D Air Search Radar
    28. 28. History of wireless communication • Guglielmo Marconi invented the wireless telegraph in 1896  Communication by encoding alphanumeric characters in analog signal  Sent telegraphic signals across the Atlantic Ocean • 1914 first voice communication over radio waves • Communications satellites launched in 1960s • Advances in wireless technology • More recently  Radio, television, mobile telephone, communication satellites  Satellite communications, wireless networking, cellular technology
    29. 29. Early uses  It was very much for entertainment often playing popular music.  It was also the fastest medium to release news.  Unlike previous publications such as newspapers the radio was instant . Radio was reserved for military uses during the first part of the 20th century.
    30. 30. 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
    31. 31. Current Wireless Systems • Cellular systems • Wireless LANs • Satellite Systems • Paging Systems • Bluetooth • Ultrawideband Radios • Zigbee Radios
    32. 32. Cellular Systems: Reuse channels to maximize capacity • Geographic region divided into cells • Frequencies/timeslots/codes reused at spatially- separated locations. • Co-channel interference between same color cells. • Base stations/MTSOs coordinate handoff and control functions • Shrinking cell size increases capacity, as well as networking burden BASE STATIO N MTS O
    33. 33. Type of Cells Satellite Macrocell Microcell Urban In-Building Picocell Global Suburban Basic Terminal PDA Terminal Audio/Visual Terminal
    34. 34. Type of Cells • Cell radii can be vary from 10’s of meters in buildings to 100’s of meters in the cities, up to several km’s in the countryside. • Macrocells, provide overall area coverage • Microcells, Microcell will focus on slow moving subscribers moving between buildings. • Picocells, Would focus on the foyer of a theater, or exhibition centre.
    35. 35. The Wireless Revolution Cellular is the fastest growing sector of communication industry (exponential growth since 1982, with over 2 billion users worldwide today) • Three generations of wireless • 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
    36. 36. 0G (Zero Generation Mobile System) At the end of the 1940’s, the first radio telephone service was introduced, and was designed to users in cars to the public land-line based telephone network. In the 1960’s, a system launched by Bell Systems, called, Improved Mobile Telephone Service (IMTS), brought quite a few improvements such as direct dialing and more bandwidth. The very first analog systems were based upon IMTS and were created in the late 60s and early 70s.
    37. 37. 1G Technology 1G refers to the first-generation of wireless telephone technology was developed in 1970’s. 1G had two major improvements: the invention of the microprocessor the digital transform of the control link between the phone and the cell site. Analog signal
    38. 38. 2G Technology Around 1980’s Better quality & capacity - More people could use there phones at the same time Digital Signals – consist of 0’s & 1’s
    39. 39. Previous Technology - 2G Digital – consist of 0’s and 1’s Digital signal:  1.Low level, 2.High level, 3.Rising edge and 4.Falling edge
    40. 40. Previous Technology - 2G Digital data can be compressed and multiplexed much more effectively than analog voice encodings Multiplexing -multiple analog message signals or digital data streams are combined into one signal For 1 and 2G standards, bandwidth maximum is 9.6 Kbit/sec, (I.E) approximately 6 times slower than an ISDN
    41. 41. Previous Technology - 2G Allows for lower powered radio signals that require less battery Power–CODEC introduction -program that encodes and decodes digital data stream or signal Translates data from digital to analog and vice versa
    42. 42. Previous Technology - 2G
    43. 43. Advantages in Previous Technology - 2G The digital voice encoding allows digital error checking increase sound quality lowers the noise level Going all-digital allowed for the introduction of digital data transfer SMS –“short message service” E-mail
    44. 44. Disadvantages in Previous Technology - 2G Cell towers had a limited coverage area Jagged Decay curve  Abrupt dropped calls  Analog –gradual sound reduction “Spotty” coverage
    45. 45. 3G Technology Large capacity and broadband capabilities Allows the transmission of 384kbps for mobile systems and up to 2Mbps Increased spectrum efficiency –5Mhz A greater number of users that can be simultaneously supported by a radio frequency bandwidth High data rates at lower incremental cost than 2G– Global roaming
    46. 46. Previous Technology - 3G CDMA –Code Division Multiple Access Form of multiplexing Does not divide up the channel by time or frequency Encodes data with a special code associated with each channel
    47. 47. Code Division Multiple Access
    48. 48. Types of Multiplexing FDMA – Frequency Division Multiple Access Each phone call is allocated one frequency for the entire duration of the call
    49. 49. Types of Multiplexing TDMA - Time Division Multiple Access Each phone call is allocated a spot in the frequency for a small amount of time, and "takes turns" being transmitted
    50. 50. Types of Multiplexing CDMA - Code Division Multiple Access Each phone call is uniquely encoded and transmitted across the entire spectrum, in a manner known as spread spectrum transmission
    51. 51. Reasons for New Research Even though 3G has successfully been introduced to mobile users, there are some issues that are debated by 3G providers and users. High input fees for the 3G service licenses Great differences in the licensing terms 3G phones are expensive
    52. 52. Fourth Generation
    53. 53. What is 4G? Fourth Generation Technology Faster and more reliable 100 Mb/s Lower cost than previous generations Multi-standard wireless system Bluetooth, Wired, Wireless Ad Hoc Networking IPv6 Core OFDM used instead of CDMA Potentially IEEE standard 802.11n Most information is proprietary
    54. 54. Communications Architecture Broadcast layer: fix access points, (i.e.) cell tower connected by fiber, microwave, or satellite (ISP) Ad-hoc/hot-spot layer: wireless LANs (i.e. internet at Starbuck’s)
    55. 55. Communications Architecture Personal Layer Gateway: devices that connect to upper layers; cell phone, fax, voice, data modem, MP3 players, PDAs Info-Sensor layer: environmental sensors Fiber-optic wire layer: high speed subterranean labyrinth of fiber optic cables and repeaters
    56. 56. Ad Hoc Networks  Spontaneous self organization of networks of devices  Not necessarily connected to internet  4G will create hybrid wireless networks using Ad Hoc networks  Form of mesh networking– Very reliable
    57. 57. Enhance Mobile Gaming Experience enhance wireless capabilities that deliver mobile gaming interaction with less than five seconds Play online multi player games while traveling at high speeds or sitting outside
    58. 58. Broadband access in Remote location 4G will provide a wireless alternative for broadband access I will provide first opportunity for broadband access in remote locations without an infrastructure to support cable or DSL access.
    59. 59. Wireless Local Area Networks (WLANs)  WLANs connect “local” computers (100m range)  Breaks data into packets  Channel access is shared (random access)  Backbone Internet provides best-effort service  Poor performance in some apps (e.g. video) 01011011 Internet Access Point 0101 1011
    60. 60. Wireless LAN Standards • 802.11b (Current Generation) • Standard for 2.4GHz ISM band (80 MHz) • Frequency hopped spread spectrum • 1.6-10 Mbps, 500 ft range • 802.11a (Emerging Generation) • Standard for 5GHz NII band (300 MHz) • OFDM with time division • 20-70 Mbps, variable range • Similar to HiperLAN in Europe • 802.11g (New Standard) • Standard in 2.4 GHz and 5 GHz bands • OFDM • Speeds up to 54 Mbps In 200?, all WLAN cards will have all 3 standards
    61. 61. Satellite Systems • Cover very large areas • Different orbit heights • GEOs (39000 Km) versus LEOs (2000 Km) • Optimized for one-way transmission • Radio (XM, DAB) and movie (SatTV) broadcasting • Most two-way systems struggling or bankrupt • Expensive alternative to terrestrial system • A few ambitious systems on the horizon
    62. 62. Paging Systems • Broad coverage for short messaging • Message broadcast from all base stations • Simple terminals • Optimized for 1-way transmission • Answer-back hard • Overtaken by cellular
    63. 63. Bluetooth • Cable replacement RF technology (low cost) • Short range (10m, extendable to 100m) • 2.4 GHz band (crowded) • 1 Data (700 Kbps) and 3 voice channels • Widely supported by telecommunications, PC, and consumer electronics companies • Few applications beyond cable replacement
    65. 65. PHYSICAL WORLD Objects ~ Gestures Gestures ~ Interaction INTERACTIVE TECHNOLOGIES
    66. 66. SOME OF INTERACTIVE TECHNOLOGIES •Multi touch Systems •Flexible screens •Multi touch IWB (Interactive White Boards) •Smart interactive Tables & multi touch desks •Microsoft Surface •SIXTH SENSE TECHNOLOGY
    67. 67. INTRODUCTION •SixthSense is a wearable gestural interface that augments the physical world around us with digital information. •Technology that plays with Human gestures to make the world more interactive and workflow much easier. •Pranav Mistry, of Indian origin, a PhD student in the Fluid Interfaces Group at the MIT Media Lab is the mastermind behind the sixth sense technology.
    68. 68. EARLIER EXPLORATIONS •Gesture interface device •Sticky notes •Pen that can draw in 3-D •Google Maps in a physical world
    69. 69. SO WHY SIXTH SENSE?? •Hereby Physical world is painted with the digital information. •You can carry your digital world with you wherever you go. •You can start with any wall or any surface as an interface even your palm.
    71. 71. CAMERA •Also called as digital eye as it analyses the digital pixels. •It captures the object in view and tracks the gestures.
    72. 72. PROJECTOR •The projector projects visual information enabling surfaces and physical objects to be used as interfaces. •It displays data sent from the smart phone on any surface in view–object, wall, or person.
    73. 73. SMART PHONE •A web enabled smart phone in the user’s pocket processes the video data. •Other software searches the web and interprets the hand gestures.
    74. 74. COLOR MARKERS •At the tip of the user’s fingers. •Helps the webcam to recognize the gestures. •The movements and arrangements of these makers are interpreted into gestures.
    75. 75. WORKING? •Images •Pictures •Gesture s Info on surface captur e Send for processing Reflect on desired surface Project image Send Info
    76. 76. APPLICATIONS
    77. 77. •Watch related videos on the newspaper articles you are reading.
    78. 78. . Check the time just by drawing a circle on the wrist.
    79. 79. •To make a call, virtual keypad is shown on your palm.
    80. 80. Get product information by using image recognition technology..
    81. 81. Get book reviews, ratings & other relevant information
    82. 82. •Get flight updates regarding timing of the flight.
    83. 83. •Projects relevant information regarding a person. • Click pictures just by forming “framing gesture”.
    84. 84. •Organize, sort & resize pictures by projecting them on a surface. •Call up the map and use thumbs & index fingers to navigate through.
    85. 85. •Zoom in & zoom out using intuitive hand movements. •Drawing application by tracking fingertip movements.
    86. 86. CONCLUSION •Integrating information to everyday objects will not only help us to get rid of the digital divide, but will also help us in some way to stay human, to be more connected to our physical world. •IT WILL NOT END UP IN MAKING US MACHINES SITTING IN FRONT OF OTHER MACHINES!!
    87. 87. Sixth Sense Technology By Pranav Mistry
    88. 88. 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
    89. 89. The END THANK YOU