cellular-communication

2. CELLULAR
COMMUNICATION
Presented By: Guided By:
Taushif. G. Sheikh Prof .V.S. Rahangdale

3. INTRODUTION TO CELLULAR
COMMUNICATIONS:
1) MOBILE COMMUNICATIONS PRINCIPLES.
2) EARLY MOBILE TELEPHONE SYSTEM
ARCHITECTURE.
3)THEORY OF OPERATION.
4)MOBILE TELEPHONE USING THE CELLULAR CONCEPT.
5) CELLULAR SYSTEM & ARCHITECTURE.
6)CELLULAR SYSTEM COMPONENTS.

4. INTRODUCTION TO CELLULAR COMMUNICATION:
1)Cellular Communication is a type of mobile communication
Cellular phone is a wireless communication just like cordless
phone. A cell is the basic geographic unit of cellular system.
2) In cell phone the distance is not restricted to within home
but one can travel in the city or even outside the city without
interruption in communication.
2)The demand for cellular mobile phone is increasing at
alarming level and is likely that wired communication will be
replaced by wireless technology.

5. 1)Each mobile uses a separate , temporary radio channel to
talk to the cell site. The site talks to many mobiles at once ,
using one channel per mobile.
2)channels use a pair of frequencies for communication one
frequency the forward link for transmitting from the cell site
and one frequency the reverse link for the cell site to receive
calls from the users .
3)Radio energy dissipates over distance, so mobile must stay
near the base to maintain communications.
MOBILE COMMUNICATION PRINCIPLES:-

7. Early Mobile Telephone System Architecture:-
1)Traditional mobile services was structured similar to television
broadcasting one very powerful transmitter located at the highest
spot in an area would broadcast in a radius of up to fifty
kilometers.
2)The cellular concept structured the mobile telephone network
using one powerful transmitter, many low power transmitters were
placed throughout a coverage area.
3)By dividing a metropolitan region into one hundred different
areas cells with low power transmitters.

8. * For Cellular Communication the frequency spectrum ranging
from 825 to 845MHz and 870 to 890MHz.Full-duplex operation
is possible by separating transmit and receive signals into
separate frequency bands.
* Cellular phone units transmit in the lower band of frequencies,
825 to 845 MHz and receive in higher band, 870 to 890MHz.The
opposite frequencies bands are used by the base units at the
cells sites.
* Within these two bands,666 separate channels(333 channels
per band) have been assigned for voice control. Each channels
occupies a bandwidth of 30KHz.

10. Mobile telephone system using the cellular
concept :
1)The ratio of the distance between areas to the transmitter
power (radius ) of the areas by reducing the radius of an area
by 50% System based on areas with 1KM radius would have
100 times more Channels than system with areas 10 KM in
radius.
2)The cellular radio equipment base station can communicate
with mobiles as long as they are within range . The Base
station communicates with mobile via a channel. The channel
is made of two frequencies, one for transmitting to the base
station and one to receive information from the base station.

11. Cellular System Architecture:
1)In modern cellular telephony, rural and urban regions are
divided into areas according to specifying provisioning guidelines.
2)Deployment parameters, such as amount of cell-splitting and
cell size, are determined by engineers experienced in cellular
system & architecture.
3) Provisioning for each region is planned according to an
engineering plan that includes cells, clusters, frequency reuse,
and handovers.

13. ClustersClusters:-
A cluster is a group of cells. No channels are reused within a
cluster.
The given fig. illustrate a seven-cell cluster.
Cells:-
1)In cellular system city is divided into small areas called “cells” &
each cell is around 10 square km (depends upon the power base
station). The cells are normally thought of hexagons. Because
cell phones & base stations use low power transmitter.
2)Each cell is linked to central location called the Mobile
Telephone Switching Office (MTSO). The cell just encompasses
only few square km area to communicate with cellular telephones.

15. Frequency Reuse:-
1)Only small number of radio channel frequencies were available
for mobile systems. The concept of frequency reuse is based on
assigning to each cell a group of radio channels used within a
small geographic area.
2)Cells are assigned a group of channels that is completely
different from neighboring cells. The coverage area of cells are
called the footprint .
3)Cells with the same number have the same set of
frequencies .The frequency reuse factor is 1/7.That is, each cell
is using 1/7 of available cellular channels.

17. Cellular System Components:-
1)The cellular system offers mobile and portable telephone
stations the same service provided fixed stations over
conventional wired loops. It has the capacity to serve tens of
thousands of subscribers in a major metropolitan area.
2)The cellular communication system consists of the following
four major components that work together to provide mobile
service to subscribers.
1. Public Switched telePhone network
(PStn).
2. Mobile telePhone Switching office
(MtSo).
3. cell Site with AntennA SySteM.
4. Mobile SubScriber unit(MSu).

18. PSTN:-
The PSTN is made up of local networks, the exchange area net works,
and the long-haul networks that interconnect telephones and other
communication device on a worldwide basis.
Mobile Telephone Switching Office(MTSO):-
The MTSO is the central office for mobile switching. It houses the Mobile
Switching Center (MSC), field monitoring and relay stations for switching calls
from cells sites to wire line central officers(PSTN).
The Cell Site:-
The Cell site is used to refer to the physical location of radio equipment that
provides coverage within a cell. A list of hardware located at a cell site
includes power sources, interface equipment, radio frequency transmitters
and receivers, and antenna systems.

19. THANKS