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CHAR, , 2, , Fundamentals of Cellular System, , 2 Unit II, Topics, Cellular, , concept, , fundamentals,, , Cll, Cells structure, Cluster, Reuse, , Minimum reuse distance,, 5asic, cellular system: Mobile station, Base station, Traffic channel (Forward factor,, and Reverse), control channel (Forwara, , and Reverse), Frequency reuse, Channel, assignment strategies., Handofi strategies:, Concept, of, handoff, Types of Handoffs : Hard, Soft, Queued, Delayed, MAHO (MoDile, Assisted Handof), Proper and, Improper Handoff, Umbrella cell approach.., Interference and system, capacity: Co-channel interference, Adjacent channel interference, Channel planning for, , wireless systems., , Improving coverage and capacity in cellular system: Cel splitting, Sectoring, Microcell Zone concept, Repeaters, for range extension., , 2.1, , Spectral congestion and user capacity was a major, problem. The service providers could not make, , Introduction to Cellular, , Telephone System, , spectrum allocations in proportion to the increasing, demand for the mobile services., , (MSBTE:S-16,W-16), , with limited radio spectrum while, same time covering large areas., , high capacity, , MSBTE Question, , a.2.1.1 State advantages of cellular system, S-16, W-16, 2 Marks, , Sec.2.1), In earlier, , days,, , a, , single high powered, , an antenna mounted on a, , large, , service, , The radio telephone system was reconstructed to obtain, , area as, , tall tower, , shown in, , transmitter with, , was, , used to, , at the, , Advantages of cellular system, The cellular concept was a major breakthrough is, solving the problem of user capacity and spectral, , cover a, , Fig. 2.1.1., Base station antenna, , congestion., , It offers, , a, , very, , high capacity, , in limited, , spectrum., , In the cellular concept, the single high power, transmitter, , is, , replaced, , with, , many, , low, , power, , transmitters each providing coverage to only a small, , part of service, , area as, , shown in, , Fig., , 2.1.2. Each base, , allocated a portion of the total number of, channels and nearby base stations are assigned different, , station is, , Service area, Base station, , Fig. 2.1.1:Single, , base station covering the complete, service area, , group of channels., The, , neighbouring base, , groups of channels, , so, , stations, , are, , assigned, , different, , that the interference between the, , base stations is minimized.

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Fundamentals, , Mobile& Wireless Comm. (MSBTE-Sem. 5-E&TC) 2-2, , a., 2.1.3, , Define:, , Base, , Base, stetlon, , Systen, , center, , Moblle, , station, , of Cellular, , switching, , (1) (Fol Table21.1), Table2.1.1), station (Ref., Base, (2), Table2.1.1), Handoff (Ret., , W-15, 3 Marks, , (9), Base, , Base, , Base, , sation, , sation, , station, , a.2.1.4, , Define, , with respen, respect, terms with, , the following, , to, , cellular system., Mobile station, , Basestation, , Base, , Base, station, , ( i )F o r w a r d c h a n n e t, , station, (N), , If these base stations and their channel groups, available, , channels, , are, , are, , market then the, , a, , throughout, , distributed, , the, , can, , be reused, , many times, The, , as, , as, , many time, , as, , possible, , or as, , essential., , co-channel, , is, , interference, , kept, , below the, , acceptance level., , spectrum., This, , S-16. 1 Mark, terms:, , the following, Q.2.1.6 Define, , (Ref. Sec. 2.1.1), , Control channels, , Sec.2.1.1), , i Mobile station (Ref. W-16. 3, Marks, MSC (Ref. Sec.2.1.1), folowing, Q. 2.1.7 Define, , components, , (aMobilestation, (b) Forward channel, , the number of, As the demand for the service increase,, an additional, base stations can be increased to supply, increase in the radio, radio capacity with no additional, , is, , theMSC., Q.2.1.5 Define, (Ref. Sec. 2.1.1), 0, , service area, , They, , S-16, 4 Marks, , (Ref.Sec.2.1.1), , Fig. 2.1.2 : Cellular concept, , systematically placed throughout, , Control channel, , Basestation controler, MSC, , (o Roamning, Transceliver(Ref. Sec. 2.1.1, , the, , communication, , principle of all, systems, , channels to service, , a, , as, , it allows, , large, , modem, a, , wireless, , number of subscribers, , reusing the channels throughout, , S-17,6 Marks, , fixed number of, , by, , the service area., , to be, The cellular concept allows each cell phone, manufactured with the same set of channels, so that any, , mobile can be used anywhere in the service region., , 2.1.1 Terminologies Associated with, , Q. 2.1.8 Define the following terms, Basestation 2. Control channe, 3, , Mobile station, , 4. Page, w-18, 4 Marks, , (Ref.Sec. 2.1.1), , Table 2.1.1: Wireless communication system definito, , Definition, , erm, , Mobile Communication, , Base station, , (MSBTE:S-15, W-15, S-16, W-16, S-17, W-18), , t, , is, , a, , fixed station in mobiE, , communication system used for, e, , radio, , MSBTE QuestionsS, , a. 2.1.2 Define fonward voice channel, reverse voice, channel.(Ref Sec.2.1.1), , S-15, 2 Marks, , Teeh-Neo Publications .Where Authors inspire ianovation, , communication, , with mooi, , centre, stations located in the, , ofat, , the edge of the cell site., , d, , SACHINSHAH, , Venture

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Fundamentals of Cellular, , Mobile &Wireless Comm. (MSBTE-Sem. 5-E&TC) 2-3, Term, , 2, , Mobile station, , System, 2 . 2 Basic Cellular, , switching, , 5, , used, , by, , the, , large service area., , Forward, channel, , Channel used for transmission, from, , base, , celular system, O 22.2 Draw block diagram of basic, , W-16. 2 Marks, , station to, , mobile, , A basic cellular system, cell site and, , mobile unit,, , Channel used for transmission, , Office (MTSO), , mobile, , S-16. W-17. 2 Marks, , (Ref. Sec. 2.2), , station., , from, , channel, , MSBTE Questions, , sc celular Syatom., , It is the, coordinating system in, mobile radio architecture, for, , centre, , Reverse, , W-17), (MSBTE: S-16, W-16,, , They are the handheld personal, mobile units or units installed in, , moving cars, subscribers., Mobile, , a, , as, , shown in, , comprises of three, , a Mobile, , station to base, , Telephone Switching, , Voloe circuite, , Control, , Radio, , channel, , transmission of call setup, call, request, call initiation and other, , channel, , used, , for, Moblle Telephone (MTS0), Swtches and proces80, , Switching Onlce, , Dedicated voice circults, , Grade circuits, , The process by which mobile, , Handoff, , a, , Fig. 2.2.1., , control signalling purpose., 7, , units:, , Land telephone network, , station., 6, , Systerm, , station is transferred from one, base station or from one channel, , to another is handoff mechanismn, Cell altes, , or handover., It, , Page, , is, , a, , messagee, , broadcasted, , over, , which is, entire, , the, , Cell site 2, , Cell site 1, , service area., , Fig. 2.2.1 :A cellular system, 9, , 10, , Transceiver, , It is the combination, transmitter and receiver., , of, , Unlts of, cellular system, , It is the phenomenon of using the, mobile on the network other than, the home network. In this VLR is, , Roaming, , responsible, , for, , () Mobile unit, , (G1) Cellsite, , roaming, , procedure., , 11, , Base, , (i) Mobile Telephone Switching Office (MTSO), , station It is the cellular network entity, , controller, , (v) Connections, , that monitors and controls the, number of base stations and, , provides the interface between, the cellsite and mobile switching, center(MSc)., , Fig. 2.2.2: Units of cellular system, , ), , Mobile unit, , It comprises a control unit, a transceiver and an antenna, , system., Tech-Neo Publications., , here Authors inspire innovation, , ASACHIN SHAH Venture

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Fundamentals of Cellular Su, Mobile&Wireless, , Comm., , System, , 2-4, , (MSBTE-Sem.5-E&TC), , Cell Geometry/Cell, , 2.3, , ) Cellsite, between the mobile, to provide interface, Its functlon is, control unit, radio, It conmprises, units and MTSO., , of a, , Cell ?, What is a, , 2.3.1, , (MSBTE:S-18,W-18, , and data terminals., cabinets, antennas, a power plant, , Ofrice (MTSO), HD) Mobile Telephone Switching, all cell sites., t is the central co-ordinating unit for, and the, t comprises of the aellular processor, , MSBTE, , Questions, , 231Define the tem, Ref. Sec. 2.3.1), , cellular switch., t interfaces the, , telephone, , zone offices., , company, , controlling, The MTSO is responsible for, the, 'operations and handling, , the call, , 23.2What, ww.w, , S-18.2 Marks, , is cell ?(Ref. Sec. 2.3.1) W-18.2 MarkeKS, , The region over which the signal strength lies above, , cellular system. Its, The MTSO is the heart of the, and, central co-ordination, processor provides, , the threshold value x dB is known as the coverage area, , cellular administration., , of a BS., , can, , be, , analog, , or, , digital, , in, , It must be a circular region, assuming BS as an, , nature., , isotropic radiator., , the mobile subscribers to other mobile, subscribers and to the nationwide telephone, t, , www., , help ot da, , base station area, antenna's coverage area that is, , activities of the subscriber., , The cellular switch, , RR, , cell with the, , The signal strength degrades as it travels away from th, , billing, , processing, , Structuree, , connects, , A group of radio channels is allocated a separate, , network., , circular base station to be used within a small, , The cellular switches use voice trunks. They, , geographic area called cell., , comprise of data links that provide supervision, , The actual radio coverage of a cell is called as a, , links between the processor and the switch and, , footprint. The footprint can be found out from the feld, , between the c I sites and the processor., , measurements or the propagation prediction models., , (iv) Connections, The radio and high speed data links connect the, , Footprint of an, , Overlap, , actual cell, , three subsystems i.e. the mobile unit, cell sites and, the MTSO0., , It carries the voice and signalling between the, mobile unit and the cell site. These links cannot be, transmitted, , standard, , telephone, , trunks. They, use microwave links or T carriers (wire lines) that, over, , AAA, , Gap-, , carry both voice and data between the cell site and, the MTSO., , Each mobile unit can use one channel, , at, , a, , time for, , its communication. But the channel is not, fixed., It can be any channel in that, service, cell site has multichannel, connect to, , area., , capabilities, , different mobile units, , Teeh-Neo Publications here, , that, , Each, can, , simultaneously., , Authors inspire inngratiaa, , Pig. 2.3.1: Footprint of cells showing the overlaps and, gaps

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Fundamentals of Cellular System, , Mobile &ireless Comm. (MSBTE-Sem. 5-E8TC) 2-5, It, , might so happen, , that either there may be, , an, , between any two such side by side circles or there, , radiation, , might be a gap between the coverage areas of two, , station antenna., , adjacent circles., , Refer Fig., , (iv), , 2.3.1. Such, , cannot serve, , as a, , are, , no, , ambiguous, , areas, , that, , belong, , to, , pattern in, , A cell must be, , circular, , omni-directional, , an, , designed, , mobiles in the service, , circular geometry, therefore, regular shape to describe cells., a, , area, , base, , to serve the weakest, , and, , they, , are located at, , given distance between, and its farthest perimeter, the center of a polygon, the largest area than the, points, the hexagon has, hexagonal, triangle and square. Thus, by using, , the, , For cells of same shape to form a tessellation so that, there, , the, , (ii) Hexagon closely approximates, , overlap, , multiple, , edge of the cell., , For, , a, , cells or to no cell, the cell shape can be of only three, , number of cells can, geometry, less, , types of regular polygons: equilateral triangle, square, , market., , cover, , only few, cells can cover a geographic region., , number of, , a circular radiation, , pattern that, , used then, If hexagonal geometry is, , or regular hexagon., , the entire, , The, , hexagon is close to, , can result from, , an, , station antenna, omni directional base, , and if there is free space propagation., But in Practice the, , used in, , corner, , sectored, , directional antennas are, , omni-directional, excited cell and the, , antennas are used, , in centre excited cells., considerations, , However, the practical, the base stations to be placed exactly, , Fig. 2.3.2 : Square and triangular cells, A hexagonal cell is the closest approximation, the system., circle. It is being typically used for, , of a, , as, , do, , not, , support, , they are seen in, , the hexagonal layout., 22.4, , Concept of Frequency, , Reusse, , (MSBTE:S-16, S-17, W-17, S-18, W-18), MSBTE Questions, , of, , Q. 24.1 Describe the concept frequency, incellular systems. (Ref.Sec.2.4), , E, , S-16, 2 Marks, , reuse. (Ref.Sec. 2.4), a. 2.4.2 Define: Frequency, , cells to proyide, , of hexagonal, returns, Fig. 2.3.3: Arrangement, without creating ambiguous, , S-16. W-17. 1 Mark, , greater coverage, The, , reasons, , square, , or, , a. 2.4.3, overQ2.4.3, the hexagonal shape, for selecting, , triangular cell shape, , are, , summarized, , Hexagon, , as, , manageable, allows easy and, , in between or can, , adjacent, , Ref., Sec. 2.4), , S-17, 4 Marks, , cellular, What is frequency planning in, W-17. 2 Marks, System?(Ret.Sec. 24), reuse, 24.5 State the advantages offrequency, , analysis of, , O., , (Ref. Sec.24, , a cellular system., , (i) In circular pattern,, , reuse, , frequency reuse, offrequency, Explain conceptof, , a. 244, , follows, , ), , reuse used, , circles can, , have gaps, , regions., create overlapping, , 6, , S-18. 2 Marks, , frequency reuse, Describe the concept of, W-18, 2 Markss, , (Ref.Sec. 24, , A SACHIN SHAH Venture, Teeh-Neo Publications., , here Authors inspire, , innovation

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2-6, &Wireless Comm. (MSBTE-Sem.5-E&TC), , Mobile, , assigned channel, different channels than, that contain completely, cells. The antennas located on base, adjacent cells, , in, The base stations, groups, , neighbouring, station are designed, the, , to obtain the, , are, , required coverage, , for, , a specific cell., , If the coverage, , area, , the cell then, , e, , is limited to within boundaries of, , same group of channels can cover, , different cells that are separated from each other by, , design, , will, The N cells, , collectively use, , available frequencies., , Stem, , the complete, set of, , It is termed as a, , cluster., , as a group of cells, ells th, that use, is defined, A cluster, different frequencies in each cell or the repeatin, called as a cluster., cells is also, pattern of, Definition of system capacity/channel, , apacity, , m, times within, cluster is repeated, the, Now if this, number, channels, duplex, the total, system, then, is, It, expressed as cha, m e a s u r e capacity., be used to, or system capacity., or system, , of, , channel, , large distances., The, , Fundamentals of Cellular, , method of, , selecting, , and, , allocating, , within, groups for all cellular base stations, , a, , channel, , system is, , capacity, , C, , mnN = mS, , 24.2), , called as frequency reuse or frequency planning., 2.4.1 shows the concept of cellular frequency, same letter use the, reuse, where cells labelled with the, , Fig., , same group of channels., In order to understand the concept of, , frequency, , reuse, , we will consider a cellular system having S duplex, channels., channels, , Then, if each cell is allocated a group if n, N cells, (n< S) and if S channels are divided among, each, into unique and disjoint channel groups with, the, , having, , same, , number of channels, then the total, , (a) 7-cell reuse pattern (N=7), , number of available radio channels is,, S, , 2.4.1, , ..(2.4.1), , nN, , C, , Cluster, , ww, , wwww.wwN, , (MSBTE: W-15, S-16, S-17, W-17, S-18, W-18), MSBTE Questions, , (b) 3-cell reuse pattern (N=3), , a. 24.7Describe concept ofcuster, , (Ref Sec.24.1), , W-15. 2 Marks, , Q. 24.7A Define cluster Draw frequency reuse pattem, forclustersize 7.(Ref. Sec 2.4.1), S-16, 4 Marks, , Q. 24.8 Define the System capacity, Ref. Sec.2.4.1), , S.16.1 Mark, , a. 24.9 Draw frequency reuse pattem for N, , and, , N 7. (Ref. Seo. 2.4.1), , O 2.4.10 Define, , Cluster size, , S-17. W-17. S-18. W.18.2 Marks, m cluster with the help o, S-18, 2 Marks, , N=4, , (c) N=4, , Fig. 2.4.1:Contd..., Tech-Neo Publications.., , Where Authors inspire innovation, , A SACHINSHAH n

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Mobile &Wireless Comm. (MSBTE-Sem. 5-E&TC), , Fundamentals of Cellular System, , 2-7, , interference. But, a smaller cluster, weaker co-channel, cells are located much, size indicates that the co channel, result in more interference., , 12, , closer together and, , 10, 2, , The value of N is, , 11, , interference, , mobile, , a, , a, or, , of, function of the amount, while, base station can tolerate, , maintaining a good quality of, , 1, , Definition offrequency, 10, , For maximum, , capacity,, , N is desired., , is, , K 12(i 2 , j = 2), , factor/frequency, , d) N=12, , Fig. 2.4.1:Frequency, , reuse, , pattern for cluster of size, , cluster is, , (a) N=7 (b) N=3 (C) N=4 (d) N=12, , (MSBTE:S-15,, , the smallest, , called, , as, , ratio, , reuse, , the, as, , possible, , value of, , frequency, , reuse, , each cell within the, , available, imes of the total, , only assigned, , and the, , hexagon has six equidistant neighbours, cell and its neighbours, lines joining the centers of any, of 60°., are separated by multiples, , W-15, S-16,W-17), , of, such that the number, The geometry of hexagon is, the, have values that satisfy, cells per cluster N can, , equation,, , State the signiicance of frequency reuse, select cell, celular system. Write procedure to, for frequency reuse.(Ref. Sec.2.42), , .(2.4.3), , N, where i, , Write about channel cape, , Hint, , ratio, , The, , MSBTE Questionns, , a.24.11, , reuse, , channels., , Channel Capacity and Selection, of Cluster Size, , a2 . 4 . 2, , communication., , andj are non-negative integers., , In order to find the, , improvemnent dueto frequency reuse, , particular cell one, , S-15, 4 Marks, custer size on system, a. 24.11A Explain effect of interference, capacity and co-channel, W-15, 2 Marks, (Ret.(Ref.Sec.24.2), , ), (i), , nearest co-channel, , must do the, , cells of, , a, , following:, , in any direction., Move i number of cells, direction, counter clockwise, Turn 60 degrees in, of cells., and move j number, , reuse ratia., a. 24.12 Define Frequency, S-16, W-17.1 Mark, , (Ref.Sec.242), , capacity is, , The channel, number, , of, , channels, , particular fixed, , that, , frequency, , maximum, defined as the, can, , for, be provided, , a, , band., , system is directly, of a cellular, capacity, the, cluster is, Thus,, of times a, the number, to, proportional, factor N is, repeated in, called as, , a, , fixed service, , size, the cluster, , select, P r o c e d u r e to, , area., , The, , 4,, and is typically, , cell, , 7, , for frquency, , or, , 12., , reuse, , repeated in, clusters can be, smal,, is, size N, If the cluster, is obtained., hence m o r e capacity, numbers and, large, between the cell, the ratio, size decreases, to, co-channel leading, A large cluster, between, distance, radius and the, , Tech-Neo Publications., , Where Authors inspire, , innovalion, , in, co-channel cells, locating, of, 2.4.2:ExamplewhereN=19(i=3,j, =2), Fig. cellularstm, , MSETE-153, /yecCIage\, ort Fanhcr., ilRY, , OTE-D672, , A, , SACHINSHAH Venture

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Fundamentals of Cellular Systemm, , Mobile&Wireless Comm.(MSBTE-Sem.5-E&TC) 2-8, Table 2.4.1 lists possible cluster sizes., , Ex.24.2, If a total of 33 MHz of bandwidth is allocated to a particula, , Table 24.1: Possible cluster size, , FDD cellular telephone system which uses two 25 kH,, , N, , simplex channels to provide full duplex voice and, , ntrol, , channels. Compute the number of channels available percell, , 2, , if a system uses (a) four-cell reuse (b) seven-cell reuse, c)12-cell reuse. If 1 MHz of the allocated spectrum i, , 4, , dedicated to control channels, determine an equitable, distribution of control channels and voice channels in each, , 12, , 3, , 13, , of the three systems., , 40, , 16, , Soln., , 32, , 19, , Given, Total bandwidth, , 4 1 21, , Channel bandwidth, , Advantages of frequency reuse, , = 33 MHz,, , = 25 kHzx 2 simplex channels, =, , 1., , Increased capacity of the system,, , 2., , Limited and Efficient utilization of the spectrum,, , 3., , Same, , 50 kHz/duplex channel, , x10, Total available channels =33, 0x, 10=60 channels, , frequency can be reused in another cell site, , (a) Four-cell reuse, , keeping the safe distance., , Total number of channels available per cell, , Ex. 24.1, Show that the, , given by ,, , frequency reuse factor for a, , o165, channels, 4, cellular system is, , where k is the average number of channels, per, , (b) Seven cell reuse, Total number and channels available per cell, , cell and S is the total number of channels available to the, cellular service provider., , Soln.:, , o7, , 95 channels, , (c) 12 cell reuse, , If each cell is allocated, , group of k channels (k < S), and if the S channels are divided among N cells into unique, and disjoint channel groups with each having the same, a, , Total number of channels available, per cell, , 660 55 channels, 12, , number of channels, the total number of radio channels, A 1 MHz, , available is,, S, , The, , =, , kN, , Where,, , N, , nere, , Cluster size, , frequency reuse factor of a system is given by 1, , ...Hence proved, Thus, proved that, , the, , frequency, , reuse, , factor for, , cellular system is given by, , a, , spectrum, , 1000x10, are, 50 x 10, , for control channel, , implies, , that, , 20 control channels out of the 660, , channels available. The 660 channels, must be eveny, distributed to each cell within the, cluster. Practically only, the 640 voice channels will, be allocated as control channels, are allocated as 1, per cell., (a) For four-cell reuse we can, have five control channels, and 160 voice, , needs, , channels, , per cell., , Practically, each ce, , single control channel. Thus, one contr, channel and 160 voice channels will be, to, assigned, a, , each cell., Tech-Neo Publications, , Where Authors inspire innovation, , A SACHINSHAHVenture

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2 . 5 Channel Assignment Strategies, The radio spectrum needs to be efficiently used. For, , this, , achieving, has, , we, , need, , consistency, , in, , a, , frequency, , increasing, , reuse, , the, , method that, , capacity, , and, , minimum interference. To achieve these objectives, different channel assignment strategies have been, , developed., The channel assignment strategies, , fixed, dynamic, , and, , hybrid depending, , performance in managing calls when, handed off from, , one, , classified, , are, , a, , on, , the system, , mobile, , cell to another., , Channel allocation schemes, , 1.Fixed, 099, , channel allocation, , AAAN00ONAANwwwwwwww.ooooeowwwww.wwwwwwww.wwwww%, , 2. Dynamic channel allocation, wwww.wwwwwwww.wwwww.wwwwwwwwwwww.ww.wwwwwwwwwwww%, , 3., , Hybrid channel allocation, ww.ww.ASKAS, , wwwwww.wwwwww.wwwwwww.wwww.w.www.wwwwwwww%, , Fig. 2.5.1 :, , as, , Channel Assignment Strategies, , user, , is

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Fundamentals of Cellular, , Moble &Wirelees Comm.(MSBTESem. 5-E&TC) 2-10, 2.5.1, , Fxed Channel Assignment, , eal-ime data, , ie. traffic distributio, , each cellis, In the fixed channel assignment.method, set of voice channels, asigned a predetermined, call a number within the cell, Any effort that is done to, unused channels in that, can be serviced by the, particular cell., , channel occupanc, etc. It, increases load on theMSC but, on, , increased, , channel, , probability of blocked call, , provides the, age, ilization and advant, redu, , Comparison of Fixed Channel Assignment a, and, Dynamic Channel Assignment, , the, In case if all the channels in that cell are used, then, call is blocked. In such a situation the subscriber does, , Table 2.5.1: Comparison of fixed channel assign, and dynamic channel assignment, , not get service., , Dynamic, , Fixed channel, , There are different modifications in the fixed channel, , assinunent, , assignment strategy., , 1., , Channel borrowing9, , Specific channels are There is no relationstin, allocated, , to, , specific | between channels and, , cells., , cells., , Channel borrowing involves borrowing channels from, , 2., , other cells or same cell. The main advantage of channel, , allocation, , The, , of The, , channels is permanent., , borrowing is that prevents cell splitting that is costty., In one method a cell is allowed to borrow channels, , 3., , from an adjacent cell if all of its channels are occupied., , No need to check for, , The borrowing procedure is supervised by the Mobile, The MSC also, , ensures, , that, , the channel borrowing does not disturb or interfere any, , In dynamic channel assignment strategy there is no, permanent allocation of channels. Every time a call, request is done, the base station requests a channel, from the Mobile Switching Centre (MSC)., , of, not, , | The algorithms used for, complexity., , 4, , It, , is, , uniform, , calls that are in progress in the donor cell., , 2.5.2 Dynamic Channel Assignment, , allocation, is, channels, permanent., , checking the availability, of channels introduces, , channel availability., , This method is called as borrowing strategy., , Switching Centre (MSC)., , System, , These strategies need the MSC to collect real-tim, , 5., , suitable, and, , traffic systems., , tolighttraffic systems., , Sensitive to time and, , Not sensitive to time, and spatial changes., , spatial changes, 6., , for It is suitable for nonheavy uniform and moderate|, , Unstable, , grade, , of | Stable grade of service, , service per cell in an | per, , cell, , in, , an, , interference cell group.|interference cell group., , 2.5.3, , Hybrid Channel Allocations, , The MSC only allocates the channel after verifying thae, the channel is not currently in use in the cell or any, other cells that comes within the minimum restricted, distance of frequency reuse to avoid co-channel, , It is the combination of fixed and dynamic channel, , allocation schemes., A fixed number of channels are allocated to cell sites, on long term basis and when they all are occupied a, , interference., , request for dynamic channel is raised., , Dynamic channel assignment strategy reduces the, , The ratio of number of fixed channels and dyname, , probability of blocking and increases the trunking, , channels is based on the traffic conditions or it may, vary according to estimated values of instantaneous, load distributions., , capacity of the system., , Teeh-Neo Publications., , Where Authors inopire innovation, , A SACHINSHAHVeatore

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Fundamentals of Cellular System, , Mobile& Wireless Comm. (MSBTE-Sem. 5-E&TC) 2-11, It is observed that Hybrid schemes perfom better for, , Definition of o0-dhamnel interterence, , In the, cells use the same set of, requeney reuse method, severat, The cells using the, frequeneies in the given servloe area., co-channel cells. The, , traffic load up to S0%, beyond that FCA gives better, results., , eame oet of channels are called as these cells is called as, ruterference between dgnale from, , 2.6 Interference and System, Capacityy, , co-channel interference., , (MSBTE:S-15, W-15, S-16, W-16, S-18), MSBTE Questionss, o 2.6.1 Define the tem co-channel. State cause and, ottect of co-chennel, , Interference on system, , they, , S-15, 4Marks, , because of out-of-band, The interference, , a. 2.6.2 Define co-channel cells. (Ref.Sec. 2.6), Define Co-channel interference., , It is, , S-16, 1 Mark, , a result, , of the front end, , equipment or, , a. 2.6.4 Describe the effect of co-channel interference, , in cellular systems. (Ref, Sec. 2.6), W-16, 2Marks, , adjacent cell,, , other base, , frequency, , band, , energy into, , or, , any, , There, , of undesired, , can, , be, , interference, , of greater, , is, , produces, , cross, , talk, , control, , in the, , of interference., , floor, RF noise, , in urban, , and large, , areas, , number, , because, , of mobiles, , and base stations., Interference, , results, , capacity., in increasing, problem, main, is, , is dropped, , There are two, 1., , 2., , calls., , types of cellular, , interferences, , Tech-Neo Publication, , channel, , interference aiects system, 6.7 How co-channel, 2.6.1, capacity ? (Ref. Sec, , W-16, S-18, 2 Marks, , w.w, , Causes, , of cochannel, , It, , causes, , of, , interference, , cochannel, , interference, , is poor, , frequency reuse, If the standard, planning., frequency, cochannel cells, comaintained in the, distance is not, to occur., interference is likely, channel, cells, , use, , the, , several, reuse method,, In the frequency, service area. The, in the given, frequencies, of, set, same, called as, channels are, same set of, cells using the, between signals, The interference, co-channel cells., co-channel, , interference., , called as, from these cels is, the, interference,, co-channel, the, reduce, a, In order to, separated by, physically, cells are, minimum distance to, , interference., , inspire, Where Authors, , osoeooosoo, , S-16. 1 Mark, , co-channels, , Co-channel interference, , Adjacent, , FrequencyReusedistance, , (Ref. Sec.26.1), , The main, , transmission., , severe, , Q.26.6Definethe, , band., , interference, , more, , MSBTE Questions, , system that leaks, , blocked calls, missed and, , result, channels as a, , The, , a, , the cellular frequency, , On voice channels,, because, , interference include another, , non-cellular, , products., , (MSBTE:S-16,W-16, S-18), , the, call that is in progress in, same, stations operating in the, , cell,, , subscriber, , Relationship, , by interference., , same, , of the, , Frequency Reuse Distance, , is highly affected, The performance of cellular systems, , mobile in the, , overload, , intermodulation, , intermittent, , S-18, 2 Marks, , of, , even, , Reduction Factor and, , in mobile communication. (Ref Sec 2.6), , sources, , is, , Co-channel Interference, , 22.6.1, , Q.2.6.5 Describe the effectof co-channel interference, , The different, , users, , control., more difficult to, , W-15. 1 Marks, , (Ret. Sec.26), , although, , the interfering signals,, It is difficult to control, within the cellular system., are generated, , capecity. (Ref. Sec.2.6), , Q. 26.3, , interference, , Definition of adjacent channel, from the channels that are, he interference resultingthe desired channel is called a, adiacent in fregueney to, ddjacentehannel interference., , provide, , isolation., , A, innovation, , Ventue, SACHINSHAH

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Fundamentals of celular Syst, , 2-12, , 5-E&TC), Mobile &Wireless Comm. (MSBTE-Sem., , of, , Co-channel, , the, samefrequency|Efect, distance that allows the, number of, system capacity, to be reused depends on factors like, co-channel cells nearby the centre cell, the type of, the, order to final, This minimum, , factor, , transmitted at each cell site., , 3NR, , Ris the radius of, As N i+ij, , i=1,j=1., , reuse, , we, , assume, , interference, Dce, , reduction, , that all the cells are of same, , same power, the, the base stations transmit, is independent of the, interference ratio, , size and, , channe, transmite, power. It becomes a function of the radius of the cel, , The frequency reuse distance D is, , where Nis the frequency, , co-channel, , In, , geographic terrain contour, antenna height and power, , D, , interference on, , (2.6.1), , the nearest co-channel, and the distance between, D. The ratioRis called as the co-channels reuse, , pattern or cluster size., , the cell., , +j the smallest value of N=3 by setting, , interference, or co-channel, , reduction, , factor., , cells, ratio, II is, , expressed as,, , Table 2.6.l, , gives different values of D for given values, , of N., , ..2.6.2), , Table 2.6.1, , The co-channel interference reduction factor, to the cluster size N as,, , Q-D/R, 2, , 2, 3, , 0, 2, , 3, , 2, , 4, , 3, , 3.00, , 4, , 2.46, , 7, , 4.58, , 9, , 5.20, , 12, , 6.0, , 13, , 6.24, , 16, , 6.93, , 19, , 7.55, , 21, , 7.94, , is related, , -3N, A, , (2.6.3), , small value of Q, , provides large capacity as the, cluster size N is small. A large Q ie. a, large value of, indicates that the spatial, separation between the, , co-channel cells relative, , to the, , coverage distance of a, , cell is increased., , Thus, the co-channel interference is reduced., But the, transmission quality is, improved. In actual design a, trade-off must be done between both., , If all, , Ex. 2.6.1 W-15, 3 Marks, , co-channel interference can occur., , Determine distance irom nearest, co-channel cel, radius 0.64 km and, co-channel reuse factor of 12 having, , Soln., , Practically, , Given: () Cell radius R, , the cell sites transmit the, same power, then, increases and the frequency reuse distance D, increases., This increased D reduces, the probability that, a, , large, , N is, , desired. However, the total, are allocated is, fixed. If N is, the, large number of channels assigned to each of, N, , number of channels that, too, , cells become small., , If the total number of channels in, N cells is, N increases then it results in, , | Tofind: Distance D, , Q, , trunking inefficiency., , D 12x0.64, , frequency reuse, , distance with a view to reduce co-channel, interference., , eeb-Neo Publications ., , ü) Reuse factor Q, , divided as, , Hence, we need to select the minimum, , here Authors inspire innovation, , =0.64 km,, =, , 12, , D/R=3N, , =, , 7.68 km, , Ans

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Moblle &Wireless Comm. (MSBTE-Sem., Mo, , Adjacent Channel Interference, , 2.6.2, , Fundamentals of Cellular System, , 5-E&TC) 2-13, , the successive channels in, , (MSBTE:S-15, S-16, W-16, S-17), MSBTE Questions, , By sequentially assigning, frequency band to different, , cells many allocation, channels in a, methods are available to separate adjacent, cell, N channel bandwidths, where N is the cluster, , by, , size., , tomadjacent, , nce State methods to reduce, Sec. 2.6.2) S-15. WN-16. S-17, 4 Marks, acent channel interterence in, , Fig., , cells in one cluster., Another cause for, , agram. How it can be minimized ?, Ref Sec. 2.6.2), S-16. 4 Marks, , interference, , that results from the, , signals, , that, , sequential assignment of, the frequency band to different, , the, , successive channels in, , elluter system, with the help of appropriate, , The, , shows, , 2.6.1, , adjacent, , channel interference is, , frequency reuse" when the frequency reuse is high, there, , are, , more, , chances for interferences* because of, , neighbouring channels and because of separation, are, , adjacent in frequency to required signal is called as, , concept., , adjacent channel interference., , Also the power control needs to properly done at the, , It is, , result of the, , a, , base station to reduce interference at the subscriberr's, , imperfect receiver filters, , that permit, the nearby frequencies into the pass band of the desired, , mobile unit., , channel., If the user that is using an adjacent channel and is, , transmitting in close range to subscriber's receiver then, while the receives tries to receive a base station on the, , 3,10, , desired channel the problem can be critical., It is called as near-far effect i.e. a nearby transmitter, captures the receiver of the subscriber., , 13, , 7,14, , If comes into picture when a mobile that is close to a, , 4,11, , base station transmits on channel near that is used by a, weak mobile., The base station can face problems in discriminating, the mobile, , from "bleed, , user, , over', , caused, , by, , 6,13, , 5,12, , close, , adjacent channel mobile., , How to reduce, , assignments the adjacent, channel interference can be minimized. As each cellis, , By, , channel, proper filter and, , cell needs, , a, given only a part of the available channels,, in, assigned channels that are adjacent frequency., , If in, , cells, , a, , given, is, , interference, , frequency separation between the, channel, large then the adjacent, , cell the, , made, can, , Tech-Neo Publications .., , Fig. 2.6.1 : Channel assignments to reduce adjacent, channel interference, , adjacent channel interference?, , be, , considerably reduced., , WWhere Authors inspire innovation, , Ex. 2.6.2, , If, , a, , 20 MHz of total spectrum is allocated for, , duplex, , a, , wireless cellular system each simplex channel has 25 kHz, RF bandwidth, find (a) the number of duplex channels and, , (b) the total number of channels per cell site if N, , =, , 4 cel, , reuse is used., , SACHIN, , SHAH Ventare

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Fundamentals of Cellular Sys, , Mobile &Wireless Comm. (MSBTE-Sem.5-E&TC) 2-14, , Soln, , ysiem, , a 2.7, , (a) To find the number of duplex channels, , 20x 10, 25x 10'x 2, , Number of duplex channels, , 400, , Ans, , w-17,S-1, , (MSBTE:S-15, W-15, S-16, S-17, W-17,:, MSBTE Questions, , Hand off mechanie m, cellular system. (Ref. Sec. 2.7), , State, , a.2.7.1, , (b) IfN=4 find the number of channels per cell, Number, , W-15. 1 Mark, , Ans., , a.2.7.3, , With neet sketch of proper and improper, situation of hend off explain when shouk, hand off take place and justiy what wi, happen it hand off not done at proper signaf, , Channel Interference, Co-channel, , Adiacent channel, , interference, , interference, , 1., , o.w.., , The, , interference, , between the signals from, co-channel cells is called, co-channel, , S, , The, , interference, , the, , adjacent, , reduce, , interference, , co-channel|, , channel, , cells, , assignments the, , physically, , adjacent, , channel, , are, , separated by a minimum, , interference, , distance, , minimized., , to, , provide, , can, , be, , large co-channel reuse Another, ratio, improves the adjacent, A, , transmission, , interference., , handoff with neat diagram., , (Ref.Sec. 2.7), , W-17.3 Marks, , Define the term handofi., Ref. Sec 2.7), , S-18, 2 Marks, , The process of transferring a mobile station from one, channel or base station to another is called as handof, or handover., , mobile moves into a different cell whie a, conversation is in progress the mobile, switching centre, a, , automatically transfers the call to a new channe, cause, , quality | interference, , for, , channel, is, , because of smaller level, of, , a.2.7.6Define hand off. Explain basic process of, , When, , sufficient isolation., 3., , S-17.2 Marks, , 0. 2.7.7, , By proper filter and, , S-16.4 Marks, , a. 2.7.5 What is Hand-off ? (Ref. Sec. 2.7), , channel, , co-channel, , improper hand-off procedure, , (Ref. Sec. 2.7), , that, , interference., To, , a. 2.7.4, , required signal is called, as, , 2., , level. (Ref. Sec. 2.7), W-15. 4Marks, llustrate with the help of heat figure proper, and, , results from the signals, that are adjacent in, , frequency, , interference., , in, , Define: Dwell time. (Ref. Sec.2.7, , a.2.7.2, , DIfference between Co-channel, Interference and Adjacent, , wwww., , the role of, , S-15. 2Marks, , 400, of channels per cell=4, 100, , 2.6.3, , Handoff Strategles, , "frequency reuse" when, co-channel the frequency reuse is, , belonging to the new base station., This handoff needs, see, , to, , identify the new base station and, , that voice and control, , new base station., , signals, , are, , allocated, , to te, , During a call in progress, if a mobile moves from oD, , high there are more, chances, for, , by, , interferencesbecause of, , essential., , cellular system to, a, , a, , different cellular system controlled, , different MSC,, , an, , intersystem handon, , separation., Tech-Neo Publications ., , here Authos inspire innovation, A SACHINSHAH Veatur

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Mobile&Wireless Comm. (MSBTE-Sem. 5-E&TC), MSC, , The, , does, , an, , signal, , intersystem handoff when a, , 2-16, , Fundamentals of Cellular System, , mobile, , becomes weak in a given cell and, MSC cannot, find other cell in its system to transfer that, call. e.g., roaming when mobile moves out of its home, , Level a, ---***--, , ndo hrehold, , (a) Impropea, ndo, fuaton, , Before, , implementing, , the, , intersystem handoff, , handoff must be accurate, at correct time, , Ime t, , --------., , instant in, , to avoid any call, , PoM Y.oellejemineted), , the, , compatibility between the two MSCs must be known., The, , ogabe onal to maintaln call, , --.., -*~-o----r-*-****, ., , system., , order, termination when there is, conversation between two users., , Proper, , Polny, , --*{Itranderëd to Baco ctatdon 2), , hando, , sttueton, Time1, , But if there is excessive, , delay, , at, , the Mobile, , Switching, , Center (MSC) in assigning handoff, the signal will, , drop, , below the minimum acceptable predetermined level in, order to enable channel in active status can lead to a, improper handoff., This minimum, , Fig. 2.7.1:Handoff situation at cell boundary, , acceptable, , level refers to, , "acceptable, , audio quality leve" at the Base Station (BS) receiver, , RSSI (Radio Signal Strength Indications), signal strength indication is defined, received at the, power of the signal that is, , Radio, , side., , measured, , A stronger signal that is slightly stronger than this, , audio quality is used, , acceptable, , Dwell, , Time, , As the mobile, , or too small from the desired level. It is expressed as,, , (BS), , handoffsignal power, , unnecessary, center., , handoffs, , Hence, A, , can, , must, , burden the mobile, , be carefully, , situation, shows the handoff, , Fig. 2.7.1(a), The, , signal, , switching, , Fig., , 2.7.1, , at cell boundary., , done., where handoff is not, shows situation, , level, , level to keep, , If there is, , chosen., , drops, , assigning the, , minimum acceptable, below the, , active., the channel, , excessive, , delay, , introduced, , handoff or if the, , dropped call event, , ., , Tech-Neo Publications, , by, , threshold, , from the, , drop, , in the, , generally, , level before, , serving, , signal, , Base Station, , level. Therefore,, , monitors and, , initiating, , measures, , the, , continuing, , a, , handoff for, , a, , call is maintained in a, , with the call in progress., , there is insufficient time to, If A is too small then, weak, before call is lost because of, complete a handoff, too large then the, conditions and if A is, , signal, , there will be, , signal, , received minimum usable signal power, , PM, , moves, , the base station, , A PaH-PM, received, , mobile, , terminal or at the base station., , A" level must be optimum and it must not be too large, , PH, , the, , threshold and, , as, , handoff has to be done at this threshold level (A). The, , Where,, , as, , the MSC is, , A is small then, , occurs., , The time period for which, , time'., cellular region is called as "dwell, dwell time, The factors that influence the, , are:, , (i) Interference, , ), , Propagation, , (ii), , subscriber and the base, Distance between the, , station., , 2.7.1, , Types of Handoff, , (MSBTE:S-15,, , W-15,S-17, W-17, S-18), , MSBTE Questions, , Queued, , Handoff and, a. 2.7.8 Definethe tem Delayed S - 1 5 . 2 Marks, handoff. (Rel. Sec. 27.1), Venture, A SACHINSHAH, , hereAutbors inspire, , innovratio

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Mobile&Wireless Comm. (MSBTE-Sem.5-E&TC) 2-16, a.2.7,0 Explain two level handoff with sultable, diagram (Ref. Sec. 2.7.1), , Fundamentalsof, 3 . Queued handofr, , W-15, 4 Marks, , An the queued handoff process,, , O.27.10 st ditterent types ot handoit. Explain any two, hdetal,(Ref. Sec. 2.7.1) S-17, 4Marks, 027.11 Ust types of handot. (Ret. Sec. 27.1), W-171 MarkK, a 2.7.12, , arranges the handoffrequests in, , These handoff requests, , various types of, station (MS):, , are, , mobile, 1. Hard handoff, , uponiin a, , manner., , queueing scheme is effective only when, , Queued hand off, , handoffs,, , in relation, , of batches or bundles., It decreases the, , 2., , Soft hand off, , the, orm, , 4., , Delayed hand off, , probability of termination of call, , because of lack of available, , channels., , It i, possible because of the fact that there is finite time, , Forced hand off, , interval between the time, , the, , received signal level, , drops below the handoff threshold and the time the, Hard Hand-off, , call is, , In the first, , generation analog cellular systems, the, time to make a handoff is 10, seconds.), , (In, , the, , mobile, , digital cellular systems, assists, , the, , handoff, , terminated, , because of, , insufficient signal, , level., 4., , Delayed handoff (two level handoff scheme), , like GSM the, , Many a times instead of one level, a two level, , procedure by, , handoff procedure is followed, in order to ensurea, , determining the hand off users and the decision, , higher possibility of a successful handoff. A hand, , needs only 1 or 2 seconds.), , off can be, , Another feature in the newer cellular systems is, , the call., , their, , ability to make handoff decisions depending, on parameters other than the, signal strengthì, Different base stations handle the different radio, chanels during a handoffcalled hard handolf. Ið, does not refer to the physical changes in the, assigned channel, but a different base station takes, care of the radio communication., , 2., , acted, , too, , handoff requests arrive at the MTSO in the fo, , with a, , -, , are then, , of, , Queueing of handoffs is mon, effective than the two threshold, handoff, Also,, sequential, , S-18.2 Marks, , 1., , MTSO, , queue instead, , busy to makes the handoff possible., , 2.7,1), , 3, , a, , rejecting them, if it finds that new cell sites are, , State the ditferent types of, handoff used in, cellular system. (Ref. Sec., , following, , Cellular System, , delayed if no available cell could acept, , Fig. 2.7.2 shows a graph of signal strength with, two handoff levels., , L lever 7i, , Received signal, strength, , L2 level 2, , Threshold level, , Softhandof, , Soft handoff refers to the ability of the Mobile, Switching Center (MSC) for selecting amongst the, , Time, , Fig. 2.7.2: Two level handoff, , different received signals from the base stations. It, , When the signal level drops below the fin, , allows the MSC to make a "'sof" decision as to which, , handoff level (L), the MS initiates a hand or, , of the user's signal will pass to the PSTN at a glance., , request., , Teeh-Neo Publications., , here Authors inspire innovation, , SACHIN, , SHAH Yentur

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Mobile, , &Wireless Comm. (MSBTE-Sem. 5-E8TC), , 2-17, , If due to some reason the mobile unit is in a place, , in a cell with low signal level (it is knovwn as hole), , or neighbouring coll is busy then the MS will, repeat the handoff request after every 5 seconds., , But if the signal strength drops down further and, reaches the second handoff level (L) then the, , bandoff will take place without any condition,, , immediately., , Fundamentals, One method is, , of Cellular Systerm, , In this method, channels in a cell is, , guard channel concept., , total available, part of the, from ongoing calls that, reserved for handoff requests, the cell., can be handed off into, the total, drawback of reducing, However, it has the, to the originating, are allocated, traffic as few channels, utilization if, efficient spectrum, calls. They offer, strategy is used., , a, , dynamic channel assignment, , Cll Dragging, , This process is called as delayed hand of., , It is, , 5 . Forced handoff, , a, , practical, , handoff, , is, systems cell dragging, , a, , microcell, problem in the, result of call of in progress, , A forced handoff is defined as the hand off which, , in the cellular region., , would normally occur but is not allowed to happen by, , level and the radio coverage, The handoffs threshold, factors that need to be, are the main, , force. It is forced for handoff to take place., , parameters, , considered to avoid "cel dragging"., , a, , Mobile Assisted Handoff, , 27.2, , (MAHO), , (MSBTE:S-18), , users that provide strong, It may result from pedestrian, when there is Line of Sight, signal to be base station,, the subscriber., between the base station and, , (LOS) path, , base station the, away from the, user, decays and as the, , 1.1SBTE Question, , When the, , a. 27.13 Explain MAHO., , average signal strength, received at, the base station, the signal, moves far from, threshold, above the handoff, the base station will be, , S-18, 2 Marks, , Mobile, generation cellular systems the, the signal strength, Switching Center supervises, first, , measurement, , done, , by, , second, base stations and in the, the handoff decisions are, , cellular systems, , generation, , mobile assisted., mobile, , In, , measures, , station, handoff, each mobile, base, received power from surrounding, , assisted, , the, , level., So, handoff need, , a handoff is, , The, , handover, , for, , is done at, , microcellular, , a, , is used, faster rate. MAHO, , environments, , where handoffs, , are, , Prioritizing Handoffs, order, , to, , improve, , the, , quality, , of service, various, , handoff, developed to prioritize, methods have been, while allocating, call initiation requests, , requests, , over, , problem, , and, , interference, , potential, , solve, "cell dragging". Thus, to, generated resulting in, the handoff thresholds, the problem of cell dragging,, , radio coverage parameters, adjusted., , and the, , should be, , carefully, , Umbrella Cell Concept, , (MSBTE: W-16), , MSBTE Question, , used, a 2.7.14 Describe how umbrela cel approach is, n celular system to reduce the number of, hand-ofis. (RetSec,2.7.3 W-16. 4 Marks, are, , several, , never, , need a, , there, Practically in cellular systems, , problems e.g., , Pedestrian, , handoff during a, , users, , call, high speed, , may, , vehicles pass, , through, , different cells quickly., A SACHNSHAH Venture, , voice channels., Teeh-Neo Publieations., , will be, be done and finally there, , initiated., , frequently done., , In, , not, , traffic management, , station., data to reporting base, stations and gives the, station of a cel|a2.7.3, received from the base, When the power, base station, received from current, exceeds the power, then, , moves, , slowly, , Rer Sec. 2.7.2, In the, , user, , bere Authors inspire, , innovation

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Fundamentals of Cellular s., , 2-18, Mobile &Wireless Comm. (MSBTE-Sem. 5-E&TC), , Sysiem, , The addition of microcells to increase the capacity has, , burdened the MSC., In cellular communication there is a possibility in which, , by Using different antenna heights and different power, , Small, microcelle, for, , levels to meet the traffic requirements i.e. large and, , small cells are collocated in a, , low, , single location., , speed tratfie, , The smaller cells are grouped and assumed to be under a, , larger cell., , Large Umbrella' cel, for high speed, trafie, , The cells with low traffic are called as "microcells" and, cells with large high speed traffic are called as, , "macrocell"., This method is called, in Fig. 2.7.3., , as, , umbrella cell concept, , as, , shown, , Fig. 2.7.3: Umbrella cell concept, , 1 s used to provide large coverage area to high speed users while providing small area covera;, , to users that, , low speeds., , travel a, , Advantages, ), , It, , provides large coverage area to high speed users., i), number of handoffs is minimized for high speed users., ii) It provides additional microcell channels for the pedestrian users., iv) If a high speed user in large umbrella cell is near the base station and if its, velocity is decreasing then the bas, station can, t ensures that the, , decide whether to hand the, , user, , Switching Centre (MSC), , 2.7.4, , into the co-located microcell without the, , intervention of the Mobile, , Difference between Hard and Soft Handoff, (MSBTE:S-15), , MSBTE Question, , Q.2.7.15 Compare hard handoff and soft hand off, operatonal, Table 2.7.1:Comparison, , procedure. (Ret. Sec. 2.7.4, , S-15, 2 Marks, , of hard handoff and soft handoff, , Sr. No., , Soft Handoff, ard, Handois, Soft handoff refers to the ability of the, Mobile, Switching Center (MSc) for selecting amongst the | Different base stations handle the different rau, channels during a handoff, different received signals from the base stations., called hard handoff., , 2, , It allows the MSC to make a "soff", decision as to, which of the user's signal will pass to the PSTN at a It does not refer to the physical changes in the, assig, | channel, but a different base, glance., station takes care Or, radio communication., , 3, , It is, , make before break process., , It is break before, make process., mobile transmits and receives from, multiple BSs | The mobile connects to, simultaneously., single BS at a time., The, , Tech-Neo Publieations, , Dere Autnors Inpire, , innovation

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Mobile &Wireless Comm., , Sr. No, , (MSBTE-Sem. 5-E&TC), , Fundamentals, , 2-19, , Soft Handoff, , of Cellular System, , Hard Handoff, , 5, , 3S., , 382, , a. Before handolf, , BS, , 8s, , BS2, , c. Ater handoff, , c. After handof, , a. Before handoff, , BS, , MS, , BS2, , b. Durlng handoff, , MS, , BS2, , b. During handoff, , Improving Coverage and, , 2.8, , Inorder to enhance the cellular coverage capacity many, , Capacity in Cellular Systems, , (MSBTE:S-16, W-16, W-17), MSBTE Questions, Q. 2.8.1 State fur ways to improve capacity and, , coverage in celluiar system. (Ref. Sec. 28), S-16, W-17, 2 Marks, , Q. 2.8.2 State the differenttechnigues usedtoimprove, capacity and coveragein celular svstem, (Ref.Sec. 2.8), W-16, 2 Marks, , To increase the coverage area in a cellular system, it is, , important to allocate more number of radio channels to, a cell so as to meet the mobile traffic., , methods are used in practice., , 2.9, , Cell Splittingg, , (MSBTE: S-15, W-15, S-16, W-16, S-17, W-17,, S-18, W-18), , MSETE Questions, , a. 2.9.1Define micro cell. (Ref Sec. 2.9), S-15, 1 Mark, with neat, Q. 2.9.2Explainconcept of cell splitting, , diagram Ref. Sec:2.9, W-15, S-17, W-17, 6 Marks, a. 2.9.3Describe cell splitting techniqua with the help, of neat sketch How it increases system, capacity ? (Ref.Sec. 2.9) S-16,4 Marks, , Hint Reter Ex. 2.9.1 for how the system, , Methods to enhance the cellular, , capacity increases), Q. 2.9.4Define the tem Cell splitting. (Ref. Sec. 2.9), , coverage capacíty, , W-16, S-18,1 Mark, , () Cell splitting, 7www, , w0, , Q.2.9.5, , (i) Cell sectoring, , Whatiscellsplitting ? State itstype., , (Ref:, , W-18,4 Marks, , Sec.2.9), , (i) Repeaters for extending range, , Cell splitting is a method of subdividing the congested, , (iv) Microcell zone concept, , cell into smaller cells, each within its, , Fig. 2.8.1: Methods to enhance, , the cellular coverage, , capacity, indicates that the coverage, More number of channels, , distance will be, , large leading, , to, , higher, , a, , base station, , decrease in the transmitter power and the, , height of the antenna., The, as, , originally congested is called, "macrocells" and the smaller cells are called, parent cell that, , was, , coverage, , capacity., Tech-Neo Publications, , following, , own, , "microcells"., A SACHINSHAH Venture, , innovation, here Authors inspire

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Fundamentals of Cellular, ar eSyNe, C )2-20, 5-E&TC), (MSBTE-Sem., , Moble &WirelessCormm., ne, , main advantage, , of, , ( ), , cellsplitting, , ine cellular capacity of the, , P l c o c e l l s, , increases, is that it, , cells, , system, implemented., , airports, , Cell spitting has specific hierarchy., , are, , (i), Civ), , (ii) Picocell, , used for, , Microcell, Femtocell, , Picocells, , Mecrocells, , improving, , areas, , are, , indoor covera, , like train stations, , adena, , etc. Typica, , is 200 meters., , available cellular, , CDMA,, , are, , used in rural, , areas, , to cover, , (1), , longer distances and traffic is less., for macrocells, , antenna, , UMTS, , technoln, , and LTE, , are, , a, , height, , that, , systems, , Less costly, , to have more, , mounted, , provides, , a, , of the surrounding buildings and, Generally they are mounted along highways., Macrocell base stations have power, , where, (3) It can be used, , land., , Also, , (4), , outputs, , of, , typically tens of watts., , th, , building, , clear over, , View, , cels and, , Allows the operator, increases the capacity of the network inside t, , (2), , on, , existing, ground based masts, rooftops and other, structures, at, , or, , Advantages, , Usually they, , The, , such a, , train station offo, in, more recently in aircraits. T, , ofpicocells, , range, , GSM,, , ), , etc.), , populated, , Refer Fig. 2.9.1., , Macrocell, , cover a small are;, , cov, , buildings (shopping malls,, , frequency, where the, , technique can be efficiently, , reuse, , generally, , These, , helps, , localization, , is important, , in improvement of outdoor, , cover, , ittle bit., , Disadvantages, , Disadvantage of a macrocell network, , Coverage area is small hence requires more number o, , Macrocell networks provide indoor coverage. To, , improve indoor coverage more number of macrocells, , picocells, (iv) Femtocell (Small Cell), , needs to be used. But that increases system cost., , A femtocell is a small cellular device base station, , i) Microcell, , designed for use in residential or small busines, Macrocells are further divided into microcells with, , environments. It is connected to the service, , smaller radi in highly populated areas by cell, , provider's network such as broadband (DSL, , spliting technique., It, , uses, , cable), , low power cellular base stations., , and, , typically supports 2-4 active mobile, , phones in a residential areas, and 8-16 active, , A, , microcell uses power control to limit the radius of, , mobile phones., , its coverage area., , It routes the mobile traffic through IP netwonk. l, , Microcells increase capacity, radio, , resource, , of the, , management becomes, , more, , difficult., , They are more sensitive to traffic variations and, interference issues as compared to macrocell., , Disadvantage of a microcell, The number of handoffs increases per cell., Tech-Neo Publications, , increases indoor coverage., , channel, but, , aWbere Authors inspire innovation, , Advantages, (1) It, , can, , provide indoor coverage for plac, macrocells cannot reach., , (2) Low cost, , where, , systems., , (3) Provides faster data, rates., , (4), , It, , helps in improveme, , of, , nacrocell, , capacity., , A SACHIN.SHATVen