This document provides an overview of the history and fundamentals of cellular communication systems. It discusses early communication networks and switching devices. It then covers the transition to digital cellular networks and describes key technologies like FDMA, TDMA, frequency reuse, and cellular structure. The document outlines generations of cellular standards and discusses aspects of cellular networks like cell shapes, sizes, splitting, and channel allocation techniques. It also covers issues like multipath fading, Doppler shift, interference, and methods to address them.

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
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.

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

9. 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

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

11. FDM
Cellular FUNDEMENTALS

12. TDM
Cellular FUNDEMENTALS

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

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

15. TDMA/FDMA
Cellular FUNDEMENTALS
Time
Frequency

16. Cellular FUNDEMENTALS
• Types of telephones
Fixed (PSTN) telephones
Cordless Telephones
Mobile Telephones
Handset The base

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

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

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

20. 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

21. Cellular FUNDEMENTALS

22. 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

23. 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

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

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

26. FUNDAMENTAL OF CELLULAR SYSTEM
Cluster size=7

27. Good Coverage requires high number
of Sites and Cells
Area Coverage 83%
Population Coverage 99,5%

28. FUNDAMENTAL OF CELLULAR SYSTEM
• Cell shape

29. FUNDAMENTAL OF CELLULAR SYSTEM

30. FUNDAMENTAL OF CELLULAR SYSTEM
cell sectorization

31. FUNDAMENTAL OF CELLULAR SYSTEM

32. FUNDAMENTAL OF CELLULAR SYSTEM
cell sectorization

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

34. FUNDAMENTAL OF CELLULAR SYSTEM

35. FUNDAMENTAL OF CELLULAR SYSTEM
cell types
- macrocell
- microcell
- picocell
Very small cells

36. Macrocell BS
BS
BS
Microcell
Microcell
FUNDAMENTAL OF CELLULAR SYSTEM

37. FUNDAMENTAL OF CELLULAR SYSTEM
Pico Cell

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

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

40. FUNDAMENTAL OF CELLULAR SYSTEM
cell splitting

41. FUNDAMENTAL OF CELLULAR SYSTEM
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
1-9 7,8,9
1,4
2,5
3,6
Fixed Dynamic Hybrid

42. FUNDAMENTAL OF CELLULAR SYSTEM
channel characteristics
- Multipath fading
t1 t2
t3

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

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

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

46. FUNDAMENTAL OF CELLULAR SYSTEM
3-Space diversity technique

47. FUNDAMENTAL OF CELLULAR SYSTEM
-Space diversity technique

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

49. 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.

50. FUNDAMENTAL OF CELLULAR SYSTEM
- Doppler shift
- +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 .

51. FUNDAMENTAL OF CELLULAR SYSTEM
- Co-channel interference
D
c

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

53. 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

54. FUNDAMENTAL OF CELLULAR SYSTEM
- Delay Spread (Time dispersion)
- Due to multipath fading
- To overcome this we use delay equalizer
1 2 3 4 65
1 2 3 4 65
Path 1
Path 2
t1 t2
t3

55. FUNDAMENTAL OF CELLULAR SYSTEM
- Distance between MS and BS
- This makes Time alignment Problem
- To overcome this system should respond to this delay
T1 T2 T3
A
B
A
B

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

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