1. Wireless & Mobile Communication
Freeha Azmat

2. Mobile Radio Communication
In last 10 years, this industry is fueled by:
Digital RF circuit Fabrication
New Large Scale Circuit Integration
Miniaturization Technologies which make portable radio equipment cheaper, smaller and more reliable

3. Electronics boom :

4. Evolution of Mobile Communication
1946:
Mobile telephone services in 25 major American cities
120KHz of RF bandwidth in half duplex mode
1950 &1960:
IMTS(Improved Mobile Telephone service) came which offered full duplex communication
IMTS became saturated due to availability of less channels

5. 1950 and 1960:
AT &T labs and other telecom companies developed the theory and techniques for cellular radiotelephony :
“The concept of breaking a coverage zone into small cells, each of which reuse portions of spectrum to increase spectrum usage at the expense of greater system infrastructure”
AT &T proposed the concept of cellular mobile system to FCC in 1968,although the technology wasn’t present to implement the concept.

6. In 1983 FCC allocated 666 duplex channels (40MHz spectrum in 800MHz band)
Additional 10MHz(166 channels) were allocated in 1989 which made the total spectrum of 50MHz

7. Frequency Allocation in the US for AMPS
January, 2006

8. Evolution AMPS (Advance Mobile Phone Service)
In 1970s,AT&T labs developed the first US cellular telephone system called the AMPS (Advance Mobile Phone Service)
By mid 1960s,the FM bandwidth of voice transmission was cut to 30KHz
ETACS(European Total Access Communication System)
Developed in 1980s
Identical to AMPS except the bandwidth was reduced to 25kHz

9. Evolution (Cont) USDC (US Digital Cellular System) :
In 1991,the first digital cellular system hardware was installed in major US cities.
Support 3 users in the same 30kHZ bandwidth
CDMA (Code Division Multiple Access):
Cellular system based on CDMA
Can support variable users in 1.25MHz wide channel
Improvement in capacity due to FM techniques

10. Major Mobile Radio Standards in North America
January, 2006

11. Major Mobile Radio Standards in Europe
January, 2006

12. Major Mobile Radio Standards in Japan
January, 2006

13. Wireless Communications System Definitions:
January, 2006

14. Wireless Communication System Definitions:

15. Types of Mobile Radio Systems:
1)Simplex
Radio/TV broadcast
2)Half-Duplex
push to talk and release to listen
3) Full Duplex:
Cell Phone
Full duplex requirement:
FDD
TDD

16. Frequency Division Duplexing(FDD)
Simultaneous Radio transmission channels for the subscriber and base station.
To facilitate FDD, it is necessary to separate the transmit and receive frequencies by about 5% of the nominal frequency.

17. Time Division Duplexing
Share a single radio channel in time
Portion of the time consumed from base station to mobile and vice versa
Preferred for indoor or small area wireless applications
Do you know why?

18. Comparison of FDD and TDD:
FDD is efficient in case of symmetric traffic
It makes radio planning easier because base stations do not hear each other.
With TDD systems, guard bands between neighboring base stations is necessary
TDD has a strong advantage where asymmetry of the uplink and downlink data speed is variable.
As the amount of uplink data increases, more bandwidth can dynamically allocated to that and vice versa

19. Paging Systems
Those communication systems that send brief messages to subscriber. The message may either be
A numeric message
An alphanumeric message
A voice message
The issued message is called Page. In modern Paging system, news headlines, stock quotations and faxes may be sent
Paging systems vary on the basis of complexity and coverage area

20. A wide area Paging System
Simulcast transmitters can be located in the same service area or in different cities and countries

21. A cordless Telephone system
1st generation Cordless Telephone systems
2nd Generation

22. A Cellular System
January, 2006

23. Definitions/Acronyms
CAI: Common Air Interface
For communication between the base station and the mobile
It has 4 different channels
FVC: Forward Voice Channel (from base station to mobile)
RVC: Reverse Voice Channel
FCC: Forward Control Channel
RCC: Reverse Control Channel
** Control channels are often called setup channels because they are involved in setting up a call and moving to unused channel
**Control channels contain handoff instructions
** Control channels make up about 5% of the total channels
January, 2006

24. Definitions/Acronyms (contd.)
MSC: Mobile Switching Center also called
MTSO: Mobile Telephone Switching office
PSTN: Public Switched Telephone Network
January, 2006

25. Call setup Procedure: 1.ESN(Electronic Serial Number):
Is unique 32bit identification number embedded in a wireless phone by the manufacturer. Each time a call is placed, the ESN is automatically transmitted to the base station.ESN cannot easily be altered in the field.ESN can be checked electronically to prevent the fraud.

26. 2.MIN(Mobile Identification number)
Is 24 bit number corresponding to the actual 7 digit telephone number assigned by the cellular carrier exclusively to a phone, used for billing and for receiving calls.
The MIN is paired with ESN. Theoretically both numbers are verified, and in combination, every time a call is placed in order to verify the legitimacy of the call and device

27. 3.System Identification Number(SID)
Is unique 5-digit number that has been assigned to identify the particular cellular carrier i.e. the service provider, from whom you are obtaining service. This number identifies your home system

28. How a Cellular Telephone Call is Made From Land line to Mobile
MIN
FCC
MIN: mobile identification number
Free channels
RCC
PSTN
MSC
MIN
January, 2006

29. Timing Diagram Illustration for Call from Land line to Mobile
Fig. 1.6
January, 2006

30. How a Cellular Telephone Call is Made From Mobile to Land line
MIN/telephone #
RCC
MIN/telephone
MIN: mobile identification number
Free channels
PSTN
MSC
January, 2006

31. Timing Diagram Illustration for Cal from Mobile to Land line
Fig. 1.7
January, 2006

32. Frequency Reuse The problems with cellular concept was:
Spectral congestion
User capacity

33. Linear Cells as an Example of Frequency Reuse
Total Band width (BW) is divided into three adjacent bands f1, f2 and f3
Such that BW = f1+f2+f3 f1 f2 f3 P I
Cell 1
Cell 2
Cell 3
Cluster 1
Cluster 2

34. Cluster Size
3 Cell Cluster
4 Cell Cluster 1 2 3 4 1 2 3