This presentation provides an overview of cellular network concepts and technologies. It introduces cellular networks and their advantages over traditional networks. It then describes key cellular network architectures including GSM and CDMA, outlining their components, functions, and differences. In summarizing the key differences, it notes that neither standard is technically superior, but that GSM allows unlocked phones between carriers while CDMA phones are carrier-locked. It also notes that LTE is being adopted as a global standard.

1. Presented by,
Najmul Hoque Munshi
M.Tech
ECE
Roll No-10210518013
Kalyani Government
Engineering College
4/27/2019 1

2. PRESENTATION OULINE
INTRODUCTION TO CELLULAR CONCEPT
ADVANTAGES OF CELLULAR SYSTEM
CELLULAR NETWORK ARCHITECTURE
WHAT IS GSM?
GSM ARCHITECTURE
FUNCTION OF COMPONENTS OF GSM
WHAT IS CDMA?
CDMA ARCHITECTURE
DIFFERENCES BETWEEN GSM & CDMA
SUMMARY
4/27/2019 2

3. INTRODUCTION TO CELLULAR CONCEPT
Cellular concept is a system level idea
which calls for replacing a single, high
power transmitter with low power small
transmitters with each providing
coverage to only a small portion of service
area.
Each base station is allocated a portion
of total no of channels available to entire
system.
Nearby base station are assigned
different groups of channels so that all
the available channels are assigned to a
relatively small no of neighbouring base
stations.
Nearby BS are assigned different
groups of channel so that interference
between BS is minimized. Figure 1: Basic Cellular Network Architecture
4/27/2019 3

4. ADVANTAGES OF CELLULAR SYSTEM
 Solves the problem of spectral congestion and user capacity.
 Offer very high capacity in a limited spectrum without major technological
changes.
 Reuse of radio channel in different cells.
 Enable a fix number of channels to serve an arbitrarily large number of users by
reusing the channel throughout the coverage region.
4/27/2019 4

5. What is GSM?
GSM stands for Global System for Mobiles.
This is a worldwide standard for digital
cellular telephony. A GSM phone is a digital
cellular technology used for transmitting
mobile voice and data services.GSM makes
use of narrow band Time Division Multiple
Access (TDMA) technique for transmitting
signals.
This circuit-switched system divides each 200 kHz channel into eight 25 kHz time-slots.
The GSM operates on the mobile communication bands 900 MHz and 1800 MHz in most
parts of the world. In the US, GSM operates in the bands 850 MHz and 1900 MHz
The GSM network is divided into three major systems: the switching system (SS), the base
station system (BSS), and the operation and support system (OSS).
The switching system (SS) is responsible for performing call processing and subscriber-
related functions. All radio-related functions are performed in the BSS, it consists of base
station controllers (BSCs) and the base transceiver stations (BTSs).The operation and support
system is to provide a network overview and support the maintenance activities of different
operations and maintenance organizations.
Figure 2: Time Division Multiple Access
4/27/2019 5

6. GSM ARCHITECTURE
Figure 3: GSM Architecture
4/27/2019 6

7. FUNCTION OF COMPONENTS OF GSM
 Mobile station (MS) : It refers for mobile station. Simply, it means a
mobile phone.
 Base transreceiver system (BTS) : It maintains the radio component
with MS.
 Base station controller (BSC) : Its function is to allocate necessary
time slots between the BTS and MSC.
 Home location register (HLR) : It is the reference database for
subscriber parameter Like subscriber’s ID, location, authentication key
etc.
 Visitor location register (VLR) : It contains copy of most of the data
stored in HLR which is temporary and exist only until subscriber is
active.
 Equipment identity register (EIR) : It is a database which contains a
list of valid mobile equipment on the network.
 Authentication center (AuC) : It perform authentication of
subscriber.
4/27/2019 7

8. What is CDMA?
Code Division Multiple Access
(CDMA) is a type of multiplexing
that enables various signals to
occupy a single transmission
channel. It enhances the use of
available bandwidth.
 CDMA is a form of spread spectrum, which simply means that data is sent in small pieces
over a number of the discrete frequencies available for use at any time in the specified range.
 All of the users transmit in the same wide-band chunk of spectrum. Each user's signal is
spread over the entire bandwidth by a unique spreading code. At the receiver, that same unique
code is used to recover the signal. Because CDMA systems need to put an accurate time-stamp
on each piece of a signal, it references the GPS system for this information. Between eight and
10 separate calls can be carried in the same channel space as one analog AMPS call. CDMA
technology is the basis for Interim Standard 95 (IS-95) and operates in both the 800-MHz and
1900-MHz frequency bands
Figure 4: Code Division Multiple Access
4/27/2019 8

9. CDMA ARCHITECTURE
Figure 5: CDMA Architecture
4/27/2019 9

10. DIFFERENCES BETWEEN GSM & CDMA
4/27/2019 10

11. SUMMARY
 First, neither GSM or CDMA is technically better; they ultimately provide the
same service and the quality of a network depends on the carrier, not the
cellular standard used.
 Second, GSM phones can be unlocked and switch carriers, whereas CDMA
phones are locked to a carrier. It’s usually cheaper to buy unlocked GSM phones
than on-contract CDMA phones.
 Third, you need to check what bands your chosen phone supports carefully.
Most either work on GSM or CDMA, and both standards offer multiple
frequencies that differ across the globe.
 Finally, LTE (Long Term Evolution) is being rolled out as a global standard.
Unfortunately, it falls victim to even more frequency division than GSM and
CDMA. The technology also suffers from limited adoption because it’s
relatively new.
 Cellular services are undergoing constant evolution and the standards
commonly supported by phones can change from year to year.
4/27/2019 11

12. 4/27/2019 12

13. REFERENCES
 Wikipedia (http://en.wikipedia.org/)
 Mobile Computing Technology, Applications and
Service Creation – Asoke K Talukder, Hasan Ahmed,
Roopa R yavagal
 Wireless Communications,Theodore S Rappaport
 Mobile Communications , J. Schiller
 Howstuffworks (http://www.howstuffworks.com/)
4/27/2019 13