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ALT CENTRE A L T T C PART I A Brief History PART II Cellular Concepts PART III GSM- Radio Interface CELLULAR MOBILE RADIO.

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Presentation on theme: "ALT CENTRE A L T T C PART I A Brief History PART II Cellular Concepts PART III GSM- Radio Interface CELLULAR MOBILE RADIO."— Presentation transcript:

1 ALT CENTRE A L T T C PART I A Brief History PART II Cellular Concepts PART III GSM- Radio Interface CELLULAR MOBILE RADIO

2 MOBILE COMMUNICATION REVOLUTION IN TELECOM. MOBILE COMMUNICATION IS A VERY RAPIDLY GROWING AND A POPULAR SERVICE. MORE THAN 40 FOLD INCREASE IN LAST 10 YEARS ALT CENTRE A L T T C IT HAS BECOME A BACKBONE FOR BUSINESS SUCCESS AND EFFICIENCY CHANGED THE LIFE STYLE ALL OVER THE WORLD.

3 MOBILE COMMUNICATION WHAT ALT CENTRE A L T T C PHONES ON THE MOVE IT ALLOWS TO COMMUNICATE TO PEOPLE WITH ANYBODY WHILE ON MOVE (PHONES FOR THE PEOPLE, NOT FOR THE PLACES) PROVIDES VOICE, FAX, SLOW SPEED DATA (today) WIRELESS APPLICATION PROTOCOL (WAP) ENABLES HIGHER BANDWIDTH ACCESS (WIRELESS ACCESS TO INTERNET)

4 ALT CENTRE A L T T C Any time Anywhere Mobility & Roaming High capacity & subs. density Efficient use of radio spectrum Seamless Network Architecture Low cost Flexibility Innovative Services Standard Interfaces MOBILE COMMUNICATION OBJECTIVES

5 MOBILE COMMUNICATION HISTORY 1946 Appeared in St.Louis USA 1970 BELL LAB introduced Cellular Principle 1979 AMPS System in US 1980s TACS & NMT systems 1990s Digital Systems ALT CENTRE A L T T C

6 MOBILE COMMUNICATION s 1980s 1990s 2000s Appeared 1G 2G 3G Analog Digital Digital MultiMulti Unified Standard Standard Standard Terrestrial Terrestrial Terr. & Sat ALT CENTRE A L T T C

7 MOBILE COMMUNICATION FREQUENCY BANDS GSM MHz (Uplink) MHz (Downlink) DCS : MHz DAMPS : MHz CDMA : MHz PDC : MHz ALT CENTRE A L T T C

8 MOBILE COMMUNICATION 1 G -analog (cellular revolution) - only mobile voice services ALT CENTRE A L T T C WIRELESS GENERATIONS 2 G - digital (breaking digital barrier) - mostly for voice services & data delivery possible 3 G - Voice & data ( breaking data barrier) - Mainly for data services where voice services will also be possible

9 MOBILE COMMUNICATION INTERNATIONAL MOBILE TELECOM ( IMT-2000) IMT  A FUTURE STANDARD IN WHICH A SINGLE INEXPENSIVE MOBILE TERMINAL CAN TRUELY PROVIDE COMMUNICATIONS ANY TIME AND ANY WHERE ALT CENTRE A L T T C THIRD GENERATION (3 G ) STANDARD

10 MOBILE COMMUNICATION INTERNATIONAL MOBILE TELECOM ( IMT-2000) ITU’s VISION FOR THIRD GENERATION MOBILE SYSTEM SINGLE UNIFIED STANDARD (Data & Multimedia Services) ANYWHERE, ANYTIME COMMUNICATION ACROSS NETWORKS, ACROSS TECHNOLOGIES, SEAMLESS OPERATION USING A SMALL POCKET TERMINAL WORLDWIDE. HIGH SPEED ACCESS 384 KB/S & 2MB/S FAST WIRELESS ACCESS TO INTERNET FULL MOTION VIDEOPHONE TERRESTRIAL & SATELLITE COMPONETS ALT CENTRE A L T T C THIRD GENERATION (3 G ) S DTANDARD

11 ALT CENTRE A L T T C CELLULAR MOBILE CONCEPTS

12 ALT CENTRE A L T T C RADIO IN LOCAL LOOP LIMITED AVAILABILITY OF RF SPECTRUM INTERFERENCE PROBLEM INTERFERENCE AND SYSTEM CAPACITY FREQUENCY REUSE PATTERN TRUNKING EFFICIENCY CELLULAR PRINCIPLE CELLULAR ENVIRONMENT CAPACITY CONSIDERATIONS FUTURE TRENDS

13 ALT CENTRE A L T T C FERQUENCY SCARCITY PROBLEM Tel Ex.    WIRED NETWORK 100,000  50 Khz = 5 Ghz (NOT POSSIBLE) Hence Individual RF Loop is not extended But a Common group of channels is shared CELLULAR MOBILE CONCEPTS

14 ALT CENTRE A L T T C ASSUMPTIONS Traffic /User = 30 mE, GOS = 1%

15 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C 360 * 25 * 2 * 1000 = 18 Mhz FOR A CELL OF 10 KM RADIUS ONLY WHICH IS IMPOSSIBLE TO BE ALLOCATED HENCE FREQUENCY REUSE IS A MUST TO COVER THE TOTAL SERVICE AREA WITH A LIMITED AVAILABLE RF RESOURCES HENCE THE NEED FOR A CELLULAR PRINCIPLE

16 ALT CENTRE A L T T C OMNI DIRECTIONAL CELLS 1 2 CELLULAR MOBILE CONCEPTS

17 ALT CENTRE A L T T C WHAT IS A CELL ? A base station (transmitter) having a number of RF channels is called a cell Each cell covers a a limited number of mobile subscribers within the cell boundaries ( Coverage area) Typical Cell Radius Aprrox = 30 Km (Start up), 1 KM (Mature)

18 ALT CENTRE A L T T C A CLUSTER OF CELLS GIVEN FREQ. RESOURCE CELLULAR MOBILE CONCEPTS

19 ALT CENTRE A L T T C D R CELLULAR PRINCIPLE N= Frequency Reuse Pattern “N”=7 Given Freq Resource CELLULAR MOBILE CONCEPTS

20 MOBILE COMMUNICATION Cellular Principle SIMULTANEOUS RE USE OF SAME FREQUENCIES AT DIFFERENT GEOGRAPHICAL LOCATIONS ALT CENTRE A L T T C SERVES MORE COVERAGE AREA REQUIRES LESS RF BW TO COVER A GIVEN AREA FREQ. REUSE INTRODUCES INTERFERENCE INTERFERENCE LIMITED SYSTEMS COMPROMISE BETWEEN SPEECH QUALITY & SYSTEM CAPACITY

21 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C CO-CHL INTERFERENCE D R Co Chl Interference is a Function of “Q” Q =D / R Lower Q Increased Co-Chl Interference  Higher Q Reduced Co-Chl Interference 

22 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C CO - Chl Interference Q = D /R =  3N N =Cluster Size R = Size (Radius of Cell) D = Distance between two Co- Chl Cells N Q=D/R Higher Q Less Interference  Higher N More Cluster Size Less RF freq/cell Less Traffic Handling Capacity of the system  LOWER Q Higher Interference  Increased System Handling Capacity  Higher Q Less Interference  Higher N More Cluster Size Less RF freq/cell Less Traffic Handling Capacity of the system

23 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C CO - Chl Interference S / I  12dB For Digital Cellular Mobile Systems Q = D/R =  3N =  6 ( S/ I)   For a propagation constant of 4

24 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C Co- Chl Interference Reduction Technique Antenna Front to Back Coupling Reduces Potential Interference Use Directional Antennas Instead of Omni Directional Antennas Potential Interferers Reduced from 6 to 2 in a three sector cell * 1 2 3f1f1 f2f2 f3f3 Three Sectored Cell Omni Directional * 1 2 3f1f1 f2f2 f3f3 Three Sectored Cell

25 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C WORST CASE Co- Chl Interference * 1 2 3f1f1 f2f2 f3f3 Three Sectored Cell Q= 4.6,N=7, S/I=14 db (Omni) S/I= 24.5 dB (Three Sectored) Q= 4.6,N=7, S/I=14 db (Omni) S/I= 29 dB (Six Sectored)

26 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C FREQUENCY REUSE PATTERN * f1f1 f2f2 f3f3 Three Sectored Cell CDMA = 1/3 ; 1 Cell Pattern & each cell with 3 sectors GSM = 4/12 ; 4 Cell Pattern & each cell with 3 sectors DAMPS = 7/21 ; 7 Cell Pattern & each cell with 3 sectors

27 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C FREQUENCY REUSE PATTERN FREQUENCY REUSE PATTERN CELL / SECTOR A three sectored cell configuration Single location Antennas looking in three directions

28 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C FREQUENCY REUSE PATTERN 4/12 7/21

29 Cell Layout (4-Cell, 3-Sectored) 1A 1B 4A 4B 4C 1C 2A 2B 2C 3A 3B 3C 3A 3B 3C 4A 4B 4C 1A 1B 1C 3A 3B 3C 2A 2B 2C 1A 1B 1C 4A 4B 4C 2A 2B 2C 1A 1B 1C 3A 3B 3C 4A 4B 4C = BTS = BSC CELLULAR MOBILE CONCEPTS

30 Frequency Assignment 1A - 1,13,25,37,49,61,73,85,97,109,121 2A - 2,14,26,38,50,62,74,86,98,110,122 1B - 5,17,29,41,53,65,77,89,101,113 1C - 9,21,33,45,57,69,81,93, CELLULAR MOBILE CONCEPTS

31 ALT CENTRE A L T T C Start Up Cells With Larger Diameter Mature Cells With Smaller Diameters Cells in city centre Smaller diameters Cells in Sub-urban areas Larger diameters

32 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C FREQUENCY REUSE PATTERN FUNDAMENTALS HIGHER “N”  IMPROVES S/I HIGHER “N”  REDUCES Traffic Chls /Cell  Reduced Traffic Handling Capacity of the system Increased RF Chs /Cell  Further Increase in Traffic Handling Capacity of the System Q = D/R =  3N =  6 ( S/ I)   Sectorization of Cells  Reduced Interference

33 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C Extract from Traffic Table - Erlang B Model

34 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C TRUNKING EFFICIENCY G O S 2%

35 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C TRUNKING EFFICIENCY More The Number Of Access Channels In A Cell Further Increase In The System Handling Capacity The Number Of Users Served In A Cell Are Directly Proportional To The Access Channels Allocated In A Cell TRUNKING EFFICIENCY It is better to have a single cell than to split into two with half the number of access channels Subs 50 subs

36 CELLULAR MOBILE CONCEPTS ALT CENTRE A L T T C An Example Assume Number of Voice Channels = 395, Average Call Duration = 2 Minutes, GoS = 2% Using Traffic Tables we get :

37 Cellular Environment Cellular Environment is quite different from fixed radio systems -Cellular approach -MOBILITY of the user -Dynamically changing surrounding terrain conditions  RF Signal attenuates, RF  d -   =4 (generally) Multipath Fading  Distortions Signal fluctuations due to mobility of the user ALT CENTRE A L T T C

38 CELLULAR ENVIRONMENT -COUNTER MEASURES Techniques Power Control Channel Coding Interleaving Equalization Slow Frequency Hopping Antenna Diversity ALT CENTRE A L T T C

39 MODULATOR b/sHz MOBILE COMMUNICATION ALT CENTRE A L T T C BASIC RADIO BASE BAND Speech Coder 32Kb/s,13Kb/s or LESS MODULATOR Spectrum &C/No Q P S K or Its Variants TRANS/RECE Cellular Principle N=1,3,4,7 TRANS/RECE BASE BAND INFORMATION

40 MOBILE COMMUNICATION ALT CENTRE A L T T C.. MOBILE SUBSCRIBER TYPICAL ARCHITECTURE MOBILE SWITCH BASE CONTROLLER BASE STATION

41 GSM CAPACITY CONSIDERATIONS ALT CENTRE A L T T C Access Channels 1--Signaling 7- Voice With 2 % GoS  2.94 E  2.94E/25mE=120 Subs 120 Subs/Sector  3 = 360 Subscribers

42 GSM CAPACITY CONSIDERATIONS ALT CENTRE A L T T C Access Channels 1--Signaling 7- Voice Access Chls 3--Signaling 29- Voice 96 Access Chls 9--Signaling 87- Voice 120  3 = 360 Subs 840  3 = 2520 Subs 3200  3 = 9600Subs

43 MOBILE COMMUNICATION PROJETED MARKET SIZE WORLD CELLULAR PCS MARKET 1N 2004 ASIA -PACIFIC35%225 M WESTERN EUROPE 30 % M NORTH AMERICA 17 % M LATIN AMERICA8 %51.5 M EASTERN EUROPE 5 % M AFRICA 3 % M MIDDLE EAST2 % 12.5 M ALT CENTRE A L T T C

44 MOBILE COMMUNICATION PROJETED MARKET SIZE CELLULAR MARKET WORLDINDIA M3 M M 25 M M More than fixed lines M ---- It won’t be long before we ask “Phones used to have wires -- why”? ALT CENTRE A L T T C

45 Public Land Mobile Network INDIA has adopted GSM standard for PLMN. Digital Cellular System. Operates at 900 MHz. International Roaming facility. Power class 0.8 to 20W. Cell Radius upto 35 Kms. Maximum mobility speed 250 Km/hr. ALT CENTRE A L T T C


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