Includes all the details about GSM and CDMA with the additional concepts of GPRS and EDGE services.the architecture of the services.

1. Presented By-
Suraj K. Yadav
MCA 2nd yr.

2. Global System for Mobile
Communication Technology
– GSM technology is a TDMA technology:
– TDMA systems assign both different frequencies (FDMA) and different time slots
(TDMA) to each transmission. Separate channels exist for uplink and downlink
transmissions.

3. Initial Era of GSM
– The first systems were activated in 1991.
– Commercial service began in 1992 and, by 1996, there were over 35 million
GSM customers being served by over 200 GSM networks.
– GSM has been deployed in the 900-, 1800-, and 1900-MHz frequency bands
– Many of the American PCS carriers chose GSM as their digital radio wireless
standard in late 1995.
– A full-rate vocoder allows for eight users (conversations) over a 200-kHz channel
(carrier):
– Each channel occupies 25 kHz
– Each GSM channel transports eight calls simultaneously.

4. GSM Architecture
– Multiple 200-kHz channels will be assigned to each base station.
– One time slot must be allocated for control channel purposes:
– Up to seven subscribers can use a 200-kHz channel
simultaneously

5. GSM Subsystems
– GSM networks are divided into four subsystems:
1. The base station subsystem (BSS)
2. The network subsystem (NSS)
3. The operations and support subsystem (OSS)
4. The mobile station subsystem

6. 1 - The Base Station Subsystem
– The base station subsystem is comprised of:
– Base station controller (BSC)
– Base transceiver station (BTS)
– The air interface
– The BTS consists of the antenna and the radio transceiver at the base station.

7. GSM Network Architecture
The GSM network architecture. Note the various subsystems. MSCs can always
connect to other MSCs. In this diagram, it’s assumed that it’s an MSC of the same
wireless carrier. OSS = operations and support subsystem.

8. Base Station Controller (BSC)
– The BSC is the control computer that manages many BTSs:
– Usually housed at the MTSO location
– Manages which radio channels are being used by which BTSs
– Also manages the call-handoff process between BTSs
– Regulates the transmit power levels of the base stations and mobile handsets.
– As a handset gets closer (farther from) to the tower, the BSC signals the mobile to
lower (increase) its transmitter power levels.
– Handle overheads associated with frequency management, call setup, and call-
handoff.

9. 2 - The Network Subsystem
– The MTSO-based switch is the central component of the network.
– Authentication center:
– Equipment Identity Register (EIR)

10. Authentication Center (AuC)
– Part of the network subsystem
– Provides the parameters needed for authentication and encryption functions.
– The Equipment Identity Register (EIR) is a database used for security.

11. MTSO-based Switch
– Provides connection to the landline PSTN.
– Provides subscriber management functions:
– Mobile registration
– Location updating
– Authentication
– Call routing to a roaming subscriber
– Houses the home location register (HLR):
– HLR is a database that registers users in a cellular network
– VLR: database that registers visitors

12. 3 - The Operations and Support
Subsystem (OSS)
– It is the command center that is used to monitor and control the GSM network.
– If a major outage occurs at a base station, the OSS can determine where that
BTS is located, what type of failure occurred, and what equipment the site
engineer will need to repair the failure.

13. 4 - The Mobile Station
Subsystem
– Consists of two components:
– The mobile handset
– The subscriber identity module (SIM)

14. The Mobile Handset
– The handset in a GSM network is different from analog phones.
– The identification information of the subscriber is programmed into the SIM
module and not the handset itself.

15. The SIM
– The SIM is a microcontroller embedded into a small piece of plastic, which
holds the GSM operating program and customer and carrier-specific data.
– Identification information of the subscriber is programmed into the SIM.
– The SIM card provides:
– Authentication
– Information storage
– Subscriber account information
– Data encryption

16. Advantages of GSM
– GSM is mature, this maturity means a more stable network with robust
features.
– Less signal deterioration inside buildings.
– Ability to use repeaters.
– The availability of Subscriber Identity Modules allows users to switch networks
and handsets at will.
– GSM covers virtually all parts of world so international roaming is not a
problem.

17. Disadvantages of GSM
– Pulse nature of transmission interferes with some electronics, especially certain
audio amplifiers.
– Intellectual property is concentrated among a few industry participants,
creating barriers to entry for new entrants and limiting competition among
phone manufacturers.
– GSM has a fixed maximum cell site range of 35 km, which is imposed by
technical limitations.

18. GSM Data Communication
Technologies: GPRS and EDGE
– General packet radio service (GPRS) is not really in use anymore in GSM
networks today.
– GPRS has been replaced by its successor technology EDGE (Enhance Data
rates for Global Evolution).

19. General Packet Radio Service
(GPRS)
– It’s been known over the years as “2.5G”.
– It implemented a packet-switched domain in addition to the circuit-switched
domain that existed in GSM networks.
– Theoretical maximum speeds of up to 171.2 kilobits per second (Kbps) were
achievable with GPRS using all eight GSM timeslots at the same time.

20. GPRS Architecture
– Before GPRS, existing MTSOs were designed to support circuit-switched traffic
and could not process packetized traffic.
– The two GPRS support nodes, required in a GPRS-enabled wireless network:
– The serving GPRS support node (SGSN)
– The gateway GPRS support node (GGSN)

21. The serving GPRS support node
(SGSN)
– SGSN performs mobility management functions such as mobile subscriber
attach/detach and location management.
– The SGSN is connected to the base station subsystem (BSS) via a connection to
the packet control unit (PCU) in the BSC.
– Handles all packet-switched data within the GSM network.
– The SGSN performs the same functions as the MTSO-based switch for voice
traffic.
– The SGSN is connected to the BSC, and is the service access point to the GPRS
network for mobile users.

22. The gateway GPRS support node
(GGSN)
– The GGSN is used as an interface to external IP networks.
– Connect to other GPRS networks to facilitate GPRS roaming operations.
– GGSNs maintain routing information that’s necessary to tunnel the
protocol data units (PDUs) to the SGSNs.

23. Comparison of GSM & GPRS
GSM GPRS
Data Rates 9.6 Kbps 14.4 to 115.2
Kbps
Modulation
Technique
GMSK GMSK
Billing Duration of
connection
Amount of data
transferred
Type of Connection Circuit – Switched
Technology
Packet -
Switched
Technology

24. Applications of GPRS
– Web browsing
– Corporate & Internet Email
– Vehicle Positioning
– Remote LAN Access
– Document Sharing/Collaborative working

25. Advantages Of GPRS
Ø We can enable internet when it is required.
Ø Internet is access even in remote areas.
Ø We can down load games, ring tones, images by visiting different web sites.
Ø It can connect to laptop or desktop.
Ø You can enjoy wireless internet connection.
Ø GPRS has high speed than GSM network.
Ø GPRS can be work in large distance or remote area.
Ø GPRS is the quick and easy to implement.

26. Disadvantages Of GPRS
ü The monthly contract cost is high.
ü It is more expensive than sms.
ü It varies between providers and countries.

27. Code Division Multiple
Access(CDMA)
– Code division multiple access (CDMA) is a fixed assignment access
– technique that uses spread spectrum and a special kind of coding
– scheme to allow the transmitters to share the media at the same
– time.

28. Why it is considered as a form of
spread spectrum technique?
– It is considered as a form of the spread-spectrum techniques,
– because the modulated coded signal has a higher bandwidth than
– the data being transmitted.

29. What can we gain from the
spreading of the spectrum?
– The immunity from the various types of noise.
– The immunity from the multipath distortion.
– It can be used as an encrypting technique.
– Several users can use the same channel with little interference.

30. Technologies based on CDMA:
– WIFI (IEEE 802.11)
– Bluetooth
– Global Positioning System (GPS)

31. Comparison of GSM & CDMA
GSM CDMA
Storage Type SIM (subscriber identity
module) Card
Internal Memory
Data transfer GPRS/E/3G/4G/LTE EVDO/3G/4G/LTE
Network service SIM specific. User has option
to select handset of his
choice.
Handset specific
Frequency band Multiple (850/900/1800/1900
MHz)
Single (850 MHz)

32. Advantages of CDMA
– Capacity is CDMA's biggest asset. It can accommodate more users per MHz
of bandwidth than any other technology.
– 3 to 5 times more than GSM
– CDMA has no built-in limit to the number of concurrent users.
– CDMA uses precise clocks that do not limit the distance a tower can cover.
– CDMA consumes less power and covers large areas so cell size in CDMA is
larger.
– CDMA is able to produce a reasonable call with lower signal (cell phone
reception) levels.
– Efficient practical utilization of fixed frequency spectrum.
– No sense of handoff when changing cells

33. Disadvantages of CDMA
– Most technologies are patented and must be licensed from Qualcomm.
– As the number of users increases, the overall quality of service decreases
– Currently CDMA covers a smaller portion of the world as compared to GSM
which has more subscribers and is in more countries overall worldwide.