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Wireless Communication and IoT

Full book of nirali prakashan bcs sem 4

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6K views99 pages

Wireless Communication and IoT

Full book of nirali prakashan bcs sem 4

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crunchyrull2
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SECOND YEAR B. Sc. COMPUTER SCIENCE Pee WIRELESS COMMUNICATION AND INTERNET OF THINGS Electronics (ELC-242) : Paper-ll S. R. CHAUDHARI Dr. J. A. BANGALI Prof. (Dr.) M. L. DONGARE Prof. (Dr.) P. B. BUCHADE Mobile and Tablet Stream videcand & Web: ie and > e a ? | Internet Connection from 76 Contents ... 4464 hon: i 4. Wireless Communication : Cellular Telephony 30 2. Short Range Wireless Technologies and Location Tracking 21-229 3. loT Architecture 3.1- 3,22 4. loT Applications 44-420, t I * Model Question Papers | and I P41 -P2 [ Unit 1 oa Wireless Communication: Cellular Telephony James Clerk Maxwell was a Scottish aientist in the field of mathematical physics yis most notable achievement was to formulate the classical theory of electromagnetic radiation, bringing together for the first time electricity, magnetism, and light as different manifestations of the same phenomenon. Maxwell's equations for lectromagnetism have been called the ) ‘second great unification in physics” where the fist one had been realized by Isaac Newton. James Clerk Maxwell 2 } 1 Overview of Wireless Communication © Wireless communication is the electromagnetic transfer of information between two or more points that are not connected by an electrical conductor. Wireless communication involves the transmission of information over a distance without the help of wires, cables or any other forms of electrical conductors. * The most common wireless technologies use radio waves. A cellular network or mobile network is @ communication network where the last link is wireless. The network i distributed over land areas called "cells'. A cellular system based on CDMA (Cod reat Multiple Access) was developed by Qual comm, Inc, and standardized by - epee STE Gb) Association (TIA) as an Interium Standard IS-95. In the e; - E> us ei ibe specialized Mobile Radio Service (MRS) was developed to co; i Y f S. cellular radio carriers. mpete with _ 7 With the rapidly increasing penetration of lapto; c | Mobile users to access I Bee ees botets Which are primar Support of Internet a Internet services like E-mail and world wide Wap ly used by ices in a mobile environment is an emergin, P (www) access, aa 9 requirement. Mobile Y ication: Cellular Tel up Wireless Communication: CONTR 5 ¥ sav) (PD fe the key problem if developin, 1 having to change jp lect. sy solv aes that attempt! fo pts t i ange physical location withou eee dicity’ to Internet users. i T - 2000) is the standard being je communication an Internet jat al offering 50-C2l bile Telecommunic ITD to set the stag} 2000 standard no! vironments (2.9- C€! i services), but will also ensure global noe delivery of services. European Telecomm : developed a third generation mobile a) Telecommunication System (UMTS), which belongs © In this chapter cellular telephony system, cellular telephony systems are explained. 4.2 Introduction of Cellular Telephon: © The cellular concept was developed by AT and T Bell Laboratories of United States in 1947, but the first tests were conducted in 1962 to explore commercial applications. The cellular radio systems rely on an intelligent allocation and reuse of channels throughout a coverage region. Each cellular base station is allocated a group of radio channels to be used within a small geographic area called a Cell. as . * Assmall geographic coverage area of a base station with the diameter of 2 to 50 km, each ‘of which allocated a number of RF channels is called a cell. Thus, a cell represents the coverage area of a base station. IP is mechanism th address, thereby : ird generation of mobil ‘onsolidate under 4 single standarg cordless telephony, satellite mobile ity in terms of global seamless roaming and ation Standards Institute (ETSI) has also nication system called Universal Mobile to the family of IMT - 2000 systems, generations and GSM, GPRS e for the thi only will lular mobile, + International Mo! developed by the systems, The IMT - different wireless en’ System + The base stations in adjacent cells ere assigned channel group which contain completely different channels than neighbouring cells. The base station antennas are desi i lesi i part chile cal igned to achieve the desired coverage within the In this technique, limiting the = coverage Ps group of channels may be used ISO the boundaries of a cell, the same another by distances large enough to keey oe oe cells that are separated from one What should be the geometric shape of : eae levels within the tolerable limits. cell, we have to consider si a cell? While deciding th i fa uch a geometric sh; - 1g the geometric shape Oo! coverage ofa ion Wi shape which cov eae ; y ee i station without overlap and has equal sic ee region ta ues of radio coverage. = shape of a call: eae secs there are three sensible choices f erag 4 A cell must be deignar on llateral triangle and ices for the geome e designed to serve the Weakest mobi ind (3) a hexagon. mobiles within the foot prints which 4” typically located at the edge of represer Of the cell, ; nt the coverage area of a by It might seem natural to choose a circle ase stati , ——_ lon, but adjacent circles cannot be overlal® £ t= (S-IV) (P-I se (Comp. Se): Elect. se jions. a map without leaving gaps or creating overlapping aoa me suitable choice. Also, an equilateral triangle does not bea f Hl -onditions of a cel Fa at given distance between the center of a ie Tees ae : f a circle and an largest area as that of a xagon has the : pte Fé ye ee using the hexagon geometry, the fewest members of a cater a hi a base station and also the hexagon oe ee ee m a Omni-directional base stat space which would occur for an Om: i ae ae So, the hexagon is a best choice for the geometric 8 on neoutl |. So, : Aekeeal shape of a cell shown in Fig. lisa conceptual a sepa, ee a of the radio coverage for each station. It has been Sa et ae eh permits easy and manageable analysis of a cellul ea propagation prediction models, Fig, 1.1: A Hexagonal Cell i i in Fig. 1.2 shows Cellular telephone network with MTSO - Mobile Telephone Switchi Te) ig. 1. Office, To/From telephone system Fig. 1.2: Cellular Telephone Network each repeater in the cell is Fesponsible for Coverage in smal] cell Although the cells are shown hexagons, in real situation the antenna pattern S will now aleve this precision, hence the celle re more likely to be apne i Some overlap, PProximately circular, with Population area, y Places ete, $9¢ of telephone AS Shown in the Fig, 1.2 Also the calls are int Not of same size. It depends on the hat area like by usiness area, school area, suburban a sey eet, (SAVE (PHD sy asec’ rected by copper cable, fiber optics and now-a.ga, ave connecter sites in a region are alled a Mobile Switching Center (MSC) or Mobi, © All the cell entral office with mvlcrowave Hink to a cer Msc ») and the MSC's are themselves interconnected so tha Office ( Telephone Switching : obile phones the system can keep track of its mo ne system can keep ected at a point of presence to the landline telephone + The cellular system Is connec network rs and vice-versa Thus, cellular phone customers can speak to landline customers 4 + note that, there is no facility for direct mobile-to-mobile communication + Here we must note th even though both mobile phones are in the same room Every call from one to other mobile goes through a cell site and a MSC only. If it js landline communication then each cell will go through PSTN. 1.2.1 Frequency Reu: Frequency use is the technique for using a specified range of frequencies more than once in the same radio system so that the total capacity of the system is increased without increasing its allocated bandwidth. * In mobile communication system use of space division multiplexing (SDM), the (three 4 dimensional) SDM allows frequency reuse. : * If one transmitter is far away from another, ie., outside the interference range, it can reuse the same frequencies. ° * Hence, in mobile phone systems frequencies are assigned to certain users which are blocked for other users. 1 * The frequencies are a scarce resource and the number of concurrent users per cell is very oe limited. Huge cells do not allow for more users. On the contrary, they are limited to less possible users per square kilometer. * This is also the reason for using very small cells in citi cities where many fe use mobile phones. ly more peop! hs 42.2 Handoff Strategies . Most advantage of cellular * The term “handover Or “hand hone c Nanda ; systems would be more sooropteta cas eat of eee Soa I «the Mobs és itis simply a change of the active cell, Pa i Switchir : ‘terface between each cel Tae {MTSO) controls all the cells and provides tt = ‘main telephone Office, i cali transceiver. «The telephone call will be routed through MTSO and through the standard system. + When the mobile phone owner crosses the cell with his vehicle, the system will automatically switch from one cell to the next. «This transfer of a call in progress from one cell to another is called handling. «The receiver in each cell base station continuously monitors the signal strength of the mobile unit. + The optimum transmission and reception through paper selection of signal is monitored by the computer situated at MTSO. Cellular carriers and frequencies are allocated with channels. The control channels are used to allocate noise channels to mobile phones. When a user dials a phone number on a mobile, the phone scans all the control channel frequencies to find the strongest frequency. This control channel is associated with the closest cell site. The mobile phone transmits on its corresponding channel and once the call has been setup the cell site assigns it a clear voice channel. The signal strength is continuously monitored to make available strongest signal while the conversation continues, similar procedure takes place for incoming calls. 1.2.3.Co-channel and Adjacent Channel Interference * A cellular system is generally characterized as a high capacity land mobile system in which available frequency spectrum is partitioned into the discrete channels which are 2ssigned in groups to geographic cells covering a cellular Geographic Service Area (GSA). The discrete channels are capable if being reused in different cells within the service area. The basic principle of a cellular system is to divide a large geographic service area into

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