2. HISTORY OF COMMUNICATION - CONTENT - communication systems overview - Introduction to Cellular Fundamentals - Network Architecture - GSM Air Interface - Digital Mobile Elements - GSM Network Protocols

3. HISTORY OF COMMUNICATION Communication systems

4. HISTORY OF COMMUNICATION Voice Communications

5. HISTORY OF COMMUNICATION Basic Communications System Elements ● Source ● Destination ● Transmission Medium Source Destination Transmission Medium

6. HISTORY OF COMMUNICATION Transmission Medium Wired Wireless Transmission Medium

7. HISTORY OF COMMUNICATION Long Distance Communications Telecommunication is the process of long distance communications. Early telecommunications involved smoke, flags, drums, and other such methods to relay messages and information.

8. HISTORY OF COMMUNICATION Telegraph The first wire line communications was the telegraph. Invented in the mid 19th century, it opened a new era in long-distance telecommunication.

9. HISTORY OF COMMUNICATION Telephone When we talk over the telephone, our voice is converted to a electronic signal by the microphone in the handset. This signal is then transmitted over telephone wires.

10. HISTORY OF COMMUNICATION Telephone Networks Early Switching Devices Switches are devices that cause a connection between two transmitting/receiving devices. Modern Switching Devices Today many different types of automated switches are used which make it possible for fast placement of calls.

11. HISTORY OF COMMUNICATION Wired VS Wireless Losses Mobility Security Bandwidth Cost

12. FUNDAMENTAL OF CELLULAR SYSTEM Transition from analog to digital Capacity Compression in digital gives more channels compatibility with other systems As ISDN (Integrated service Digital Network) Cost Quality Security

13. ELEMENTS OF DIGITAL MOBILE 1 0 0 0 : 1 1 1 0 1 0 0 : 1 1 0 0 0 1 0 : 1 0 1 0 0 0 1 : 0 1 1 G = 1 1 1 0 : 1 1 1 1 1 0 1 : 1 1 1 1 0 1 1 : 1 1 1 H = C = D G = ( 1 0 1 1 : 0 0 1 ( D = ( 1 0 1 1 ) THIS IS SENT OVER THE CHANNEL CHECK AT THE RECIVER S = C H T = ( 0 0 0 ) S = C H T = ( 1 0 1 ) = IF WE RECIVER ERROR AT BIT No. 5 C = ( 1 0 0 1 : 0 0 1 ) 5

14.  Some techniques used in wireless communication: FDM TDM FDMA TDMA Cellular FUNDEMENTALS

15. FDM FDM Cellular FUNDEMENTALS

16. TDM Cellular FUNDEMENTALS

17. Frequency FDMA FDMA  FDMA is the division of each bandwidth (RX,TX) into many frequency bands (channels) Cellular FUNDEMENTALS

18. TDMA  It allows several users to share the same radio frequency (RF) by dividing it into different timeslots Time Frequency Cellular FUNDEMENTALS

19. TDMA/FDMA Cellular FUNDEMENTALS Time Frequency

20. Cellular FUNDEMENTALS Types of telephones Fixed (PSTN) telephones Cordless Telephones Mobile Telephones HandsetThe base

21. Modes OF Transmission in wireless  Simplex communication system  Example:  Television, radio TXRX Communication is possible in one direction only Cellular FUNDEMENTALS

22.  Half – Duplex communication system  Example :  Police radio TX+RX Two-way communication on the same channel. At any given time a user can only transmit or receive Cellular FUNDEMENTALS

23.  Full – Duplex communication system  Example :  GSM mobile radio TX+RX simultaneous two-way communication Two simultaneous but separate channels are provided for communication to and from the terminals Cellular FUNDEMENTALS

24. Simple growth was the single transmitting/receiving station Simple growth was the single transmitting/receiving station - heavy, bulky and expensive - no switching between regions - low quality - limited capacity - rapid market saturation - power hungry transceiver - power level was not safe MS High transmitted power Up link Down link Cellular FUNDEMENTALS

26. First generation cellular system First generation cellular system - Introduction of analog cellular systems in the late 1970s and 1980s - analog system - incompatible systems - limited to voice service - no encryption - FM modulation - FDMA transmission technology - suffer from capacity saturation Cellular FUNDEMENTALS

27. NMT 900 TACS JTACS/ NTACS 820830840850860870880890900910920930940950 MCS AMPS/ NAMPS 960 820830840850860870880890900910920930940950960 UplinkDownlink 824849869 894 UplinkDownlink 905 935 885 Downlink 925 Uplink 915935 Downlink 885 925 Uplink MHz 1G Frequency Bands 1G Frequency Bands Cellular FUNDEMENTALS

28. Systems of first generation Systems of first generation Cellular FUNDEMENTALS

29. Second Generation cellular system Second Generation cellular system - Introduction of digital cellular systems (90’s) - development of unified international standard for mobile communications - pan-national roaming - digital encryption - enhanced range of services (data + voice) - low power consumption - light weight, compact and pocket size terminals - TDMA transmission technology - huge capacity Cellular FUNDEMENTALS

31. Third generation cellular system Third generation cellular system - Multimedia services - W-CDMA transmission technology - Large BW - Higher Bit Rate - More Services Cellular FUNDEMENTALS

32. FUNDAMENTAL OF CELLULAR SYSTEM The cellular structure The cellular structure - area divided into small zones (cells) - area divided into small zones (cells) - cells grouped into clusters - cells grouped into clusters - this gives less power usage - this gives less power usage - enable frequency reuse - enable frequency reuse

33. FUNDAMENTAL OF CELLULAR SYSTEM Cluster size=7

34. FUNDAMENTAL OF CELLULAR SYSTEM Cell shape Cell shape

35. FUNDAMENTAL OF CELLULAR SYSTEM

36. cell sectorization cell sectorization

37. FUNDAMENTAL OF CELLULAR SYSTEM

38. cell sectorization cell sectorization

39. FUNDAMENTAL OF CELLULAR SYSTEM adaptive power control adaptive power control - as cellular mobile moves power seen at Bs changed - as cellular mobile moves power seen at Bs changed - so we use adaptive power control to maintain it - so we use adaptive power control to maintain it P1 P2

40. FUNDAMENTAL OF CELLULAR SYSTEM

41. cell types cell types - macrocell - microcell - picocell Very small cells

42. Macrocell BS Microcell FUNDAMENTAL OF CELLULAR SYSTEM

43. Pico Cell

44. FUNDAMENTAL OF CELLULAR SYSTEM Satellite Global Subur ban & rural Urban Pico-Cell Micro-Cell Macro-Cell In-building Pico-Cell

45. FUNDAMENTAL OF CELLULAR SYSTEM cell splitting cell splitting - as traffic load increases in a cell - as traffic load increases in a cell - to increase channels designer tend to split cell into - to increase channels designer tend to split cell into smaller cells smaller cells - R decrease Dc decrease so more capacity - R decrease Dc decrease so more capacity

46. FUNDAMENTAL OF CELLULAR SYSTEM cell splitting cell splitting

47. FUNDAMENTAL OF CELLULAR SYSTEM channel allocation techniques channel allocation techniques - Fixed channel assignment technique (less Ts) - dynamic channel assignment technique (largest Ts) - hybrid channel assignment technique (Improved) 1,4,7 2,5,8 3,6,9 1-97,8,9 1,4 2,5 3,6 Fixed Dynamic Hybrid

48. FUNDAMENTAL OF CELLULAR SYSTEM channel characteristics channel characteristics - Multipath fading

49. FUNDAMENTAL OF CELLULAR SYSTEM -It gives a Rayleigh fading distribution - Rayleigh fading is frequency selective selective

50. FUNDAMENTAL OF CELLULAR SYSTEM To overcome multipath fading we use :To overcome multipath fading we use : - Microscopic diversity and combining techniques - Frequency hopping - Error correction - Interleaving technique - adaptive power control

51. FUNDAMENTAL OF CELLULAR SYSTEM -Microscopic diversity techniques : 1-Time diversity technique 1-Time diversity technique 2-Frequency diversity technique 2-Frequency diversity technique

52. FUNDAMENTAL OF CELLULAR SYSTEM 3-Space diversity technique

53. FUNDAMENTAL OF CELLULAR SYSTEM -Space diversity technique

54. FUNDAMENTAL OF CELLULAR SYSTEM - Combining techniques : 1-Selective technique 1-Selective technique - used in mobile due to simplicity - used in mobile due to simplicity 2-Maximal ratio technique 2-Maximal ratio technique - Best fading reduction - Best fading reduction 3-Equal gain technique 3-Equal gain technique Receiver comparator

55. FUNDAMENTAL OF CELLULAR SYSTEM - Shadow fading -The Solution of this problem by using Macroscopic Diversity By selecting a BS which is not shadowed when others are. -The Solution of this problem by using Macroscopic Diversity By selecting a BS which is not shadowed when others are.

56. FUNDAMENTAL OF CELLULAR SYSTEM - Doppler shift - +ve if the mobile moves toward the BS - +ve if the mobile moves toward the BS - -ve if the mobile moves away from the BS - The Doppler frequency shift should be compensated so that a correct frequency synchronization is achieved. a correct frequency synchronization is achieved.

57. FUNDAMENTAL OF CELLULAR SYSTEM - Co-channel interference DcDc

58. FUNDAMENTAL OF CELLULAR SYSTEM - Adjacent channel interference Frequency Signal level (dB) Filter Required ch. Adjacent channel interference

59. FUNDAMENTAL OF CELLULAR SYSTEM - Channel management 1,8,15 2,9,16 5,12,19 6,13,20 7,14,21 4,11,18 3,10,17 Frequency (MHz) Amplitude

60. FUNDAMENTAL OF CELLULAR SYSTEM - Delay Spread (Time dispersion) - Due to multipath fading - To overcome this we use delay equalizer 123465 123465 Path 1 Path 2

61. FUNDAMENTAL OF CELLULAR SYSTEM - Distance between MS and BS - This makes Time alignment Problem - To overcome this system should respond to this delay T1T2 T3 A B A B

62. FUNDAMENTAL OF CELLULAR SYSTEM - Path loss Pr α Pt R β R β β = 3 ~ 4 β = 3 ~ 4 Signal level (dB) Distance

63. FUNDAMENTAL OF CELLULAR SYSTEM - Combined signal loss Path loss Rayleigh fading Shadowing Signal level (dB) Log d