Download Mobile Computing: An Introduction to Wireless Networks and GPRS and more Summaries Computer Applications in PDF only on Docsity!
THIRUVALLUVAR UNIVERSITY
STEERED BY
E-NOTES
BECS 63B / BECA 63B
MOBILE COMPUTING
(6th^ SEMESTER B.Sc CS / BCA )
Dr. S. THAMARAI SELVI, M.E., Ph.D., Vice Chancellor, Tiruvalluvar University, Serkkadu, Vellore
COMPILED BY
1. Dr. S. SELVAKANI, M.C.A.,M.Phil.,M.Tech., Ph.D., Assistant professor & Head, Department of Computer Science, Thiruvalluvar University College of Arts and Science, Arakkonam. 2. Ms. A. SIVASANKARI, M.Sc.,M.Phil., DCP., Assistant Professor , Department of Computer Applications, Shanmuga Industries arts and science college, Tiruvannamalai. 3. Mr. V. SAKTHIVEL, M.C.A., M.Phil., Assistant Professor & Head , Department of Computer Applications, Shanmuga Industries arts and science college, Tiruvannamalai. 4. Mrs. G. KOMALA, M.C.A., M. Phil., B.Ed., Assistant Professor , Department of Computer Applications, Shanmuga Industries arts and science college, Tiruvannamalai. 5. Ms. S. R. RATHINA PRIYA, M.C.A.,M.Phil., Assistant Professor , Department of Computer Applications, Shanmuga Industries arts and science college, Tiruvannamalai. 6. Mrs. E. SUGANYA, M.C.A.,M.Phil., Assistant Professor , Department of Computer Applications, Shanmuga Industries arts and science college, Tiruvannamalai.,
ACKNOWLEDGEMENT
Writing an e-content is harder than we thought and more rewarding than we could
have ever imagined. None of this would have been possible without our honourable
Vice Chancellor – Professor Dr. S. Thamarai Selvi. Her dynamism, vision, sincerity,
guidance and motivation have deeply inspired us. She worked her magic on every
page in this e-content, reorganised content wherever necessary, bringing value added
words in every line. She has taught us the way to present the content to the students in
a best possible way to have clear and crisp understanding. She was able to tune into
the task and identify the ones that diverted our team focus and energy keeping us from
getting our things done. It was a great privilege and honour to work under her
guidance. We are extremely grateful for what she has offered us.
Dr. S. SELVAKANI A. SIVASANKARI
V. SAKTHIVEL G. KOMALA
S. R. RATHINAPRIYA E. SUGANYA
TEXT BOOKS:
- Jochen Schiller, “Mobile Communications”, Second Edition, Pearson Education, 2003. 2. William Stallings, “Wireless Communications and Networks”, Pearson Education, 2002. REFERENCE BOOKS:
- KavehPahlavan, PrasanthKrishnamoorthy, “Principles of Wireless Networks”, PHI/Pearson Education, 2003.
- UweHansmann, LotharMerk, Martin S. Nicklons and Thomas Stober, “Principles of Mobile Computing”, Springer, 2003..
- Raj Kamal, “Mobile Computing”,Oxford University Press, 2007
- Asoke K. Talukdar, “Mobile Computing”, Tata McGraw-Hill Education,2010.
- Mohammad Ilyas , Imad Mahgoub,” Mobile Computing Handbook” ,AUERBACH,2004.
- Vilas S. Bagad , “Mobile Computing Introduction”, Technical Publications,
- DR SANJAY Sharma, “Mobile Computing”,S.K. Kataria & Sons Publication,2014.
- Dr. Ashish N.Jani, Dr. N.N. Jani , Neeta Kanabar ,” Mobile Computing - Technologies and Applications”, 2010
- Pattnaik, Prasant Kumar, Mall, Rajib, “ Fundamentals Of Mobile Computing”, Second Edition, PHI Learning Pvt. Ltd., 2015.
UNIT - I
MOBILE COMPUTING
1. WIRELESS COMMUNICATION
1.1 INTRODUCTION
Wireless communication involves the transmission of information over a distance without the help of wires, cables or any other forms of electrical conductors. Wireless communication is a broad term that incorporates all procedures and forms of connecting and communicating between two or more devices using a wireless signal through wireless communication technologies and devices. 1.1.1 FEATURES OF WIRELESS COMMUNICATION The evolution of wireless technology has brought much advancement with its effective features. The transmitted distance can be anywhere between a few meters (for example, a television's remote control) and thousands of kilometers (for example, radio communication). Wireless communication can be used for cellular telephony, wireless access to the internet, wireless home networking, and so on. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mice, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones.
Miners in the outback can rely on satellite phones to call their loved ones, and thus, help improve their general welfare by keeping them in touch with the people who mean the most to them. Convenience Wireless communication devices like mobile phones are quite simple and therefore allow anyone to use them, wherever they may be. There is no need to physically connect anything in order to receive or pass messages. Example − Wireless communications services can also be seen in Internet technologies such as Wi-Fi. With no network cables hampering movement, we can now connect with almost anyone, anywhere, anytime. Speed Improvements can also be seen in speed. The network connectivity or the accessibility were much improved in accuracy and speed. Example − A wireless remote can operate a system faster than a wired one. The wireless control of a machine can easily stop its working if something goes wrong, whereas direct operation can’t act so fast. Accessibility The wireless technology helps easy accessibility as the remote areas where ground lines can’t be properly laid, are being easily connected to the network. Example − In rural regions, online education is now possible. Educators no longer need to travel to far-flung areas to teach their lessons. Thanks to live streaming of their educational modules. Constant connectivity Constant connectivity also ensures that people can respond to emergencies relatively quickly. Example − A wireless mobile can ensure you a constant connectivity though you move from place to place or while you travel, whereas a wired land line can’t.
1.1.3 TERMS IN MOBILE TELEPHONY
Among the various terms used in Mobile telephony, the most used ones will be discussed here. Mobile Station (MS) − The Mobile Station (MS) communicates the information with the user and modifies it to the transmission protocols of the air interface to communicate with the BSS. The user information communicates with the MS through a microphone and speaker for the speech, keyboard and display for short messaging and the cable connection for other data terminals. The mobile station has two elements Mobile Equipment (ME) and Subscriber Identity Module (SIM). Mobile Equipment (ME) − ME is a piece of hardware that the customer purchases from the equipment manufacturer. The hardware piece contains all the components needed for the implementation of the protocols to interface with the user and the air-interface to the base stations.
FIGURE 1.2 MOBILE EQUIPMENT
The following image illustrates the parts of different sub-systems. HLR, VLR, EIR and AuC are the sub-systems of Network sub-system.
FIGURE 1.4 NETWORK SUB-SYSTEM
Channels − It is a range of frequency allotted to particular service or systems. Control Channel − Radio channel used for transmission of call setup, call request, call initiation and other beacon or control purposes. Forward Control Channel(FCC) − Radio channel used for transmission of information from the base station to the mobile Reverse Channel(RC) − Radio channel used for transmission of information from the mobile to base station. Voice Channel(VC) − Radio channel used for voice or data transmission. Handoff − It is defined as the transferring a call from the channel or base station to another base station. Roamer − A mobile station which operates in a service area other than that from which service has been subscribed
Transceiver − A device capable of simultaneously transmitting and receiving radio signals. Wireless communications is, by any measure, the fastest growing segment of the communications industry. As such, it has captured the attention of the media and the imagination of the public. Cellular systems have experienced exponential growth over the last decade and there are currently around two billion users worldwide. Indeed, cellular phones have become a critical business tool and part of everyday life in most developed countries, and are rapidly supplanting antiquated wireline systems in many developing countries. In addition, wireless local area networks currently supplement or replace wired networks in many homes, businesses, and campuses. Many new applications, including wireless sensor networks, automated high ways and factories, smart homes and appliances, and remote telemedicine, are emerging from research ideas to concrete systems. The explosive growth of wire- less systems coupled with the proliferation of laptop and palmtop computers indicate a bright future for wireless networks, both as stand-alone systems and as part of the larger networking infrastructure. However, many technical challenges remain in designing robust wireless networks that deliver the performance necessary to support emerging applications. In this introductory chapter we will briefly review the history of wireless networks, from the smoke signals of the pre-industrial age to the cellular, satellite, and other wireless networks of today. We then discuss the wireless vision in more detail, including the technical challenges that must be overcome to make this vision a reality. We describe current wireless systems along with emerging systems and standards. The gap between current and emerging systems and the vision for future wireless applications indicates that much work remains to be done to make this vision are ability. 1.1.4 HISTORY OF WIRELESS COMMUNICATIONS A digital radio can transmit a continuous bit stream or it can group the bits into packets. The latter type of radio is called a packet radio and is characterized by bursty transmissions: the radio is idle except when it transmits a packet. The first network based on packet radio, ALOHANET, was developed at the University of Hawaii in 1971. This network enabled
1882 – American physicist, Amos Emerson Dolbear, was granted a patent for a wireless transmission system using an induction coil, microphone and telephone receiver and battery. Nathan Stubblefield transmitted audio signals without wires. 1883 – Irish physicist and chemist George Francis FitzGerald published a formula for the power radiated by a small loop antenna. 1884 – German physicist Heinrich Rudolf Hertz wrote Maxwell’s equations in scalar form by discarding the concept of aether reducing it from 20 to 12 equations. 1885 – Thomas Edison patented a system of wireless communication by electrostatic induction. 1886 – Heaviside introduced impedance as the ratio of voltage over current. Hertz started his work to demonstrate the existence of radio waves and published his results in 1888. 1887 – English physicist Oliver Joseph Lodge discovered Sympathetic Resonance (standing waves) in wires. 1888 – Hertz produced, transmitted, and received electromagnetic waves (5 m to 50 cm) using reflectors to concentrate the beam. Hertz also discovered the principle for Radar. Heaviside wrote Maxwell’s equations in vector form – the four equations we use today. Italian Galileo Farrari and Croatian-American Nilola Tesla independently produced rotating fields using 2-phase currents. Austrian engineer Ernst Lecher established the relation between frequency, wire length, velocity of propagation and the electrical constants of the wire. 1890 – Lecher used standing waves produced in parallel wires to measure frequency. Tesla introduced high frequency currents in therapeutics as he observed that current of high frequency could raise the temperature of living tissue. Tesla also patented his Tesla Coil which was used later in every spark gap generator to produce high frequency signals. Heinrich Rubens and R. Titter made a sensitive bolometer which measured the intensity of electromagnetic waves by means of the heat generated in a thin wire. 1893 – English physicist Joseph John Thomson published the first theoretical analysis of electric oscillations within a conducting cylindrical cavity of finite length suggesting the
possibility of wave propagation in hollow pipes (waveguides). Hertz conducted experiments of EM shielding and for coaxial configuration. 1895 – Marconi transmitted and received a coded message at a distance of 1.75 miles near his home in Bologna, Italy. Indian physicist, Sir Jagadis Chunder Bose generated and detected wireless signals and produced many devices such as waveguides, horn antennas, microwave reflectors and more. 1897 – Marconi demonstrated a radio transmission to a tugboat over an 18 mile path over the English Channel. The first wireless company, Wireless Telegraph and Signal Company was founded – they bought most of Marconi’s patents. Lord Rayleigh suggests EM wave propagation in waveguides and analysis of propagation through dielectrically filled waveguides. Lodge patented various types of antennas. 1899 – Marconi sent the first international wireless message from Dover, England to Wimereux, France. 1900 – Tesla obtained patents on System of Transmission of Electrical Energy which the US recognized as the first patents on Radio. Tesla is the first person to describe a system of determining the location of an object using radio waves – Radar. 1902 – Fessenden patented the Heterodyne receiver. American Cornelius D. Ehret filed patents covering the transmission and reception of coded signals or speech (Frequency Modulation – FM). Poulsen was the first to develop the CW transmitter. 1903 – Marconi established a transmission station in South Wellfleet, MA – the dedication included exchanges of greetings between American President Theodore Roosevelt and British King Edward VII. G. 1904 – Frank J. Sprague developed the idea of the printed circuit. W. Pickard filed a patent application for a crystal detector where a thin wire was in contact with silicon. It was the central component in early radio receivers called crystal radios. J. C. Bose was granted a patent on point contact diodes that were used for many years as detectors in the industry. Fleming suggested the rectifying action of the vacuum-tube diode for detecting high frequency oscillation
- the first practical radio tube.
1916 – Leon m Brillouin and Georges A. Beauvais patented the R-C coupled amplifier. F. Adcock used open vertically spaced aerials for direction finding in aircraft and granted British patent. 1918 – Armstrong invented the Super heterodyne Radio Receiver using 8 valves – most receivers still use this design today. Langmuir patented the feedback amplifier. E. H. O Shaughnessy development of direction finding was one of the key weapons in England during WWI – Bellini-Tosi aerials were installed around the coast to locate transmission from ships and aircrafts. Louis Alan Hazeltime invented the neutrodyne circuit with tuned RF amplifier with neutralization. 1919 – Marconi-Osram company developed the U-5 twin-anode full-wave rectifier. Joseph Slepian filed a patent application for a vacuum tube electron multiplier. Sir Robert Alexander Watson-Watt patented a device for radiolocation by means of short-wave radio waves
- the forerunner of the Radar system. 1921 - E. S. Purington made the all-electric frequency modulator. A.W. Hull invented the Magnetron oscillator operating at 30 kHz and output power of 8 kW and 69 percent efficiency. E. H. Colpitt and O. B. Blackwell developed modulation of an audio frequency carrier by signals of lower audio frequency for carrying telephony over wires. S. Butterworth published a classic paper on HF resistance of single coil considering skin and proximity effect. 1922 – Walter Guiton Cady invented the piezoelectric (Quartz) crystal oscillator. The BBC broadcasts is first news program. 1923 – The decibel (1/10th^ of a bel, after A. G. Bell, inventor of the telephone) was used to express the loss in a telephone cable. H. W. Nichols developed point-to-point communication using single side-band communication. D.C Prince analyzed Class A and Class C amplifiers. Scottish engineer Antoine Logie Barid built and patented the first practical TV. Watson-Watt perfected the radiolocation device by displaying radio information on a cathode ray oscilloscope telling the radar operator the direction, distance and velocity of the target. Ralph Vinton Lyon Hartley showed that the amount of information that can be transmitted at a given time is
proportional to the bandwidth of the communication channel. H. Flurschein filed a patent on radio warning system for use on vehicles. 1924 – J.R. Carson showed that energy absorbed by a receiver is directly proportional to its bandwidth and extended Lorentz’s reciprocity theory to EM fields to antenna terminals. Lloyd Espenschied invented the first radio altimeter. The mobile telephone was invented by Bell Telephone Company and introduced to NYC police cars. 1925 – First conference on frequency allocation was held in Geneva. Joseph Tykocinski- Tykociner demonstrated that the characteristics of a full size antenna can be replaced with sufficient accuracy from measurements made on a small short wave in the rage of 3 to 6 m. 1926 – L.E. Lilienfield patented the theory of the Field-Effect Transistor. Japanese engineers Hidetsugu Yagi and Shintaro Uda developed the Yagi antenna, a row of aerials consisting of one active antenna and twenty undriven members as a wave canal. Hulsenback and Company patented identification of buried objects using CW radar. 1927 – R. V. Hartley developed the mathematical theory of communications. Harold Stephen Black of Bell Laboratories conceived the negative feedback amplifier. A. de Hass studied fading and independently developed diversity reception system. 1928 – Baird conducted the first transatlantic TV broadcast and built the first color TV. Nyquist published a classic paper on the theory of signal transmission in telegraphy. He developed the criteria for the correct reception of telegraph signals transmitted over dispersive channels in the absence of noise. C.S. Franklin patented the coaxial cable in England to be used as an antenna feeder. 1929 – L. Cohen proposed circuit tuning by wave resonance (resonant transmission line) and its application to radio reception. H.A. Affel and L. Espenscheid of AT&T/Bell Labs created the concept of coaxial cable for a FDMA multi-channel telephony system. K. Okabe made a breakthrough in cm-waves when operating his slotted-anode magnetron (5.35 GHz). Hans Erich Hollmann patented the idea of a reflex klystron with his double-grid retarding-field tube. W.H. Martin proposed the Decibel as a transmission unit.
1937 – Grote Rober constructed the first radio telescope. W. R. Blair patented the first anti-aircraft fire control radar. Russell H. Varian and his brother Sigurd Varian along with William Hansen developed the reflex Klystron. Alex H. Reeves invented pulse-code modulation for digital encoding of speech signals. 1938 – E. L. Chaffee determined the optimum load for Class B amplifiers. IRE published standards on transmitters, receivers and antennas. Claude Elwood Shannon recognized the parallels between Boolean algebra and the functioning of electrical switching systems. W. R. Hewlett developed the Wien-bridge (RC) oscillator. P. H Smith at RCA developed the well known Smith Chart. N. E. Lindenblad of RCA developed a coaxial horn antenna. John Turton Randall and Albert Boot developed the cavity magnetron that becomes the central components to radar systems. 1941 – W. C. Godwin developed the direct-coupled push-pull amplifier with inverse feedback. Siemens & Halske made the Ge diode – R. S. Ohl made the Si junction diode. Sidney Warner realized a two-way police FM radio. 1943 – H. J. Finden developed the frequency synthesizer. Austrian engineer Rudolf Kompfner developed the traveling wave tube. C. K. Chang developed frequency modulation of RC oscillators. C. F. Edwards developed microwave mixers. H. T. Friis developed noise figures of radio receivers. 1944 – Harold Goldberg suggested pulse frequency position modulation. E. C Quackenbush of Amphenol developed the VHF coaxial connectors. Paul Neil of Bell Labs developed Type N connectors. Maurice Deloraine, P. R. Adams and D. H. Ranson applied for patents covering switching by pulse displacement a principle later defined as time-slot interchange – Thus, Time-Division Multiplexing (TDMA) was invented. Radio Research Lab developed radar countermeasures (jamming) in the 25 MHz to 6 GHz range. 1946 – S. L. Ackerman and G. Rappaport developed a radio control systems for guided missiles. E. M. Williams developed the radio frequency spectrum analyzer.
1947 – G. E. Mueller and W. A. Tyrrel developed the dielectric rod antenna. John D. Kraus invented the helical antenna. W. Tyrell proposed hybrid circuits for microwaves, H. E. Kallaman constructed the VSWR indictor meter. 1948 – W. H. Branttain, J. Bardeen and W. Shockley of Bell Labs built the junction transistor. E. L. Ginzton and others developed distributed wideband amplifier using pentodes in parallel. Shannon laid out the theoretical foundations of digital communications in a paper entitled “A Mathematical Theory of Communication.” Paine described the BALUN. 1949 – E. J. Barlow published the principle of operation of Doppler Radar. 1950- J. M. Janssen developed the sampling oscilloscope. 1951- Charles Hard Townes published the principle of the MASER (Microwave Amplification by Stimulated Emission of Radiation). The Laboratoire Central des Telecommunications in Paris developed the first model of a time-division multiplex system connecting subscriber line by electronic gates handling amplitude modulated pulses. 1952 – C. L. Hogan demonstrated a microwave circulator. 1955 – R. H. DuHamel and D. E. IsBelll develop the log periodic antenna. John R. Pierce proposed using satellites for communications. Sony marketed the first transistor radio. 1957 – Soviet Union launched Sputnik I that transmitted telemetry signals for about 5 months. German physicist Herbert Kroemer originated the concept of the heterostructure bipolar transistor (HBT). 1958 – Robert Noyce (Intel) and Jack Kilby (TI) produced the first Si integrated circuit (IC). 1962 – G. Robert-Pierre Marie patented the wide band slot antenna. S. R. Hofstein and F. P. Heiman developed MOS IC. 1963 – W. S. Mortley and J. H. Rowen developed surface acoustic wave (SAW) devices. John B. Gunn of IBM demonstrated microwave oscillations in GaAs and InP diodes. The Institute of Electrical and Electronic Engineers (IEEE) was formed by merging the IRE and AIEE.
