GSM and CDMA are two mobile network technologies. GSM was developed in Europe in the 1980s and uses TDMA to allow multiple users to access the network simultaneously. CDMA was developed later and uses code division multiple access, assigning each user a unique code. CDMA provides better voice quality and spectral efficiency compared to GSM. However, GSM networks and compatible devices are more widespread globally. Both technologies have continued to evolve with newer standards like GSM's EDGE and CDMA2000.

1. Presentation on
GSM Vs. CDMA
– - Santoshkumar S M

2. The History
GSM
– During the early 1980s, analog cellular telephone systems were
experiencing rapid growth in Europe, particularly in Scandinavia
and the United Kingdom, but also in France and Germany.
– In 1982 the Conference of European Posts and Telegraphs (CEPT).
– The study group called Groupe Spécial Mobile (GSM).
– First outcome of this group was a Pan-European Public Land
Mobile System, which is an Analog system.

3. GSM : The History
– Commercial service was started in mid-1991, and by 1993 there
were 36 GSM networks in 22 countries with Ph-I Spec. of ETSI.
– Earlier 1994, Over 200 GSM networks (including DCS1800 and
PCS1900) are operational in 110 countries around the world.
– GSM systems exist on every continent, and the acronym GSM
now aptly stands for Global System for Mobile communications.
This is now a Digital system.
– Advancements in compression algorithms and DSPs would allow
the fulfillment of the original criteria and the continual
improvement of the system in terms of quality and cost.

4. GSM : The Architecture

5. GSM : The Architecture
Mobile Station :
– The mobile station (MS) consists of the mobile equipment (the
terminal) and a smart card called the SIM.
– The mobile equipment is uniquely identified by the International
Mobile Equipment Identity (IMEI). The SIM card contains the
International Mobile Subscriber Identity (IMSI) used to identify
the subscriber to the system, a secret key for authentication, and
other information. The IMEI and the IMSI are independent,
thereby allowing personal mobility. The SIM card may be
protected against unauthorized use by a password or personal
identity number.
–

6. GSM : The Architecture
– Base Station Subsystem
– The Base Station Subsystem is composed of two parts, the Base
Transceiver Station (BTS) and the Base Station Controller (BSC).
These communicate across the standardized Abis interface,
allowing (as in the rest of the system) operation between
components made by different suppliers.
– It handles radio-channel setup, frequency hopping, and handovers,
as described below. The BSC is the connection between the mobile
station and the Mobile service Switching Center (MSC).
– GSM systems exist on every continent, and the acronym GSM
now aptly stands for Global System for Mobile communications.
This is now a Digital system.

7. GSM : The Architecture
– Network Subsystem
– The central component of the Network Subsystem is the Mobile
services Switching Center (MSC). It acts like a normal switching
node of the PSTN or ISDN, and additionally provides all the
functionality needed to handle a mobile subscriber, such as
registration, authentication, location updating, handovers, and call
routing to a roaming subscriber.
– The Home Location Register (HLR) and Visitor Location Register
(VLR), together with the MSC, provide the call-routing and
roaming capabilities of GSM.
– The location of the mobile is typically in the form of the signalling
address of the VLR associated with the mobile station.

8. GSM : How do you get Connected…
– This is done through Radio Links. The ITU allocates units of
spectrum bands for a particular service providers. Usually, ranges
from 890-915 MHz for uplink & 935-960 for downlink.
– This method chosen by GSM is a combination of Time- and
Frequency-Division Multiple Access (TDMA/FDMA).
– The fundamental unit of time in this TDMA scheme is called a
Burst period and it lasts 15/26 ms (or approx. 0.577 ms).
– Eight burst periods are grouped into a TDMA frame which forms
the basic unit for the definition of logical channels. One physical
channel is one burst period per TDMA frame.

9. GSM : Reason for NOT REACHABLE
– A traffic channel (TCH) is used to carry speech and data traffic.
Traffic channels are defined using a 26-frame multiframe, or group
of 26 TDMA frames. Out of these…
– TCHs for the uplink and downlink are separated in time by 3 burst
periods, so that the mobile station does not have to transmit and
receive simultaneously, thus simplifying the electronics.
– BSNL – 2, Spice Telecom – 2.35, Hutch – 2.80, Airtel- 2.9
and
some AT&T Networks in UK&USA makes use of 3Burst periods.
This affects the data & speech transmission(ISDN).
– The next generations of connectivity, to avoid some of demerits of
GSM, “ Universal Mobile Telecommunication System (UMTS).”

10. PLATFORMS

11. CDMA

12. The History
– During 1985, ITU founded another group Interim Working Group,
which was into determination of overall objectives of FPLMTS.
This study came up with the benefits of integrating Terrestrial &
satellite components.
– This has boosted for dividing up the signal into many tiny fractions
of a second, allowing three times as many people to use the system
at the same time.
– In 1992, San Diego's Qualcomm Inc. introduced a new flavor of an
idea that has been used in military satellites for decades.
And that is C D M A…

13. – TIA endorsed a wideband CDMAOne for ITU 3G solution and
LG was the first company to introduce this data service
worldwide. In 2000, This technology came to India.
• The CDMA path in brief:
CDMA2000 technology, data rates increase from 115Kbps to over
2Mbps. CDMA phones are already capable of handling packet data
(data broken up into manageable chunks, each containing the
destination address—the kind of data transmission used in the
Internet). CDMA networks use standard Internet protocol (IP)-
based equipment.

14. Merits with C D M A …
• Good subjective speech quality
• Support for international roaming
• Support for range of new services and facilities
• Spectral efficiency
• The output stream is 64Kbps & compatible special quality of
SIMs.
Demerits with C D M A …
• Handsets are more sensitive to handling & costlier.
• Switching to different services is almost not possible.
• Service providers are few in number. (RIL, Idea, Tata)

15. GSM Vs. CDMA
GSM CDMA
• 56 Kbps • 64 Kbps, 2Mbps
• Conferencing- Impossible • Possible
• Mixing (Cross-connection) • Rarely
• Radiations are harmful. • Less harmful.
• Voice clarity not so good. • Best
• Compatibility is not good. • Its good
• GPRS enabled, but poor quality pics & MP3 downloads.
• Handsfree connectivity & Clarity.

16. ACRONYMS
1x— The first phase of CDMA2000
1xEV— An enhancement to CDMA2000 (1x) that includes HDR
3G— Third Generation of mobile communications
3x— CDMA2000 using three carriers of 1.25 MHz each
8 PSK— Eight-phase-shift keying
AMPS— Advanced Mobile Phone Service

17. Acronyms
CDG— CDMA Development Group
CDMA— Code Division Multiple Access
CDMA2000— The CDMA solution for 3G as defined by the TIA
EDGE— Enhanced Data rates for Global Evolution
ETSI— European Telecommunications Standards Institute
FPLMTS— Future Public Land Mobile Telecommunications
System

18. Acronyms
GMSK— Gaussian minimum-shift keying
GPRS— General Packet Radio Service
GPS— Global Positioning System
GSM— Global System for Mobile Communications (originally
Groupe Spécial Mobile)
HDR— High Data Rate
IMT2000— International Mobile Telecommunications

19. Acronyms
IP— Internet protocol
IS-2000— The standard written by the TIA for 3G CDMA
ITU— International Telecommunications Union
TDMA— Time division Multiple Access
TIA— Telecommunications Industry Association
UMTS— Universal Mobile Telecommunications System
UPT— Universal Personal Telecommunications
WCDMA— Wideband CMDA