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1. Mobile Communication
Akshaya Behera
SDE, BSNL

2. Introduction
Mobile communication is widely known as
Global System for Mobile communication(GSM).
GSM is a 2nd generation cellular standard
developed to cater voice and data.
It was first deployed in Finland in
December 1991. By 2010, it became a global
standard for mobile communications achieving
over 90% market share and operating in over
193 countries and territories.

3. GSM History
Years Events
1982 Conference of European Posts and Telegraph (CEPT) establishes a GSM group
to widen the standards for a pan-European cellular mobile system.
1987 Time Division Multiple Access(TDMA) is chosen as the access method. The
initial Memorandum of Understanding(MoU) is signed by telecommunication
operators representing 12 countries.
1988 GSM system was validated.
1889 The European Telecommunications Standards Institute (ETSI) was given the
responsibility of the GSM specifications.
1991 Commercial launch of the GSM service occurs.

4. Generation
• 1st Generation: Analog mobile technology
supports only voice.
• 2nd Generation: Digital mobile technology
supports voice and data.
• 3rd Generation: Technology supports video call
and enhanced data speed.
• 4th Generation: Technology supports VoLTE
and high speed data.

5. Evolution

6. Data Speed
• 1G: No data at all
• 2G: Data speed of 9.6kbps
• 2.5G(GPRS): Data speed 35kbps – 120kbps
• 2.75G(EDGE): Data speed 120kbps – 384kbps
• 3G(UMTS): Data speed 384kbps – 2mbps
• 3.5G(HSPA): Data speed 1mbps – 3mbps
• 4G(LTE): Data speed 3mbps – 21mbps

7. GSM specification
GSM uses circuit switched system which
divides 200khz signal into 8 x 25khz and
operates in 900MHz & 1800MHz. There are 124
channels in 900MHZ band.
900 Frequency band
890MHz – 915MHz(Uplink)
935MHz – 960MHz(Downlink)

8. No of people
can talk at a
time
•One tower has 3 sectors
•One sector can use group
of 8 time slot at a time.
•One time slot duration is
0.577msec
•One sector can use
maximum of 4 group of
time slot.
•So 32 people can talk in a
sector
•96 people can talk in a
tower

9. Modulation
Modulation is the process of converting data
into signals optimized for transmission by adding
information to a carrier signal.
Types of Modulation
• Amplitude Modulation
• Frequency Modulation(FDD)
• Phase Modulation

10. Frequency Modulation

11. GSM Architecture

12. Mobile Station
Mobile Equipment:
• Portable hand held device
• Contains uniquely identified 15 digit IMEI(International Mobile Equipment
Identity) number. Call *#06#
• Monitors power & signal quality of surrounding cells.
Subscriber Identity Module:
• Contains 15 digit IMSI(International Mobile Subscriber Identity) number.
Example: 404-76-5671237890
• Can be protected by PIN
• Authentication & ciphering

13. Base Station Subsystem(BSS)
Base Transceiver Station(BTS)
• Communicates with MS & BSC
• Encoding, encrypting, multiplexing, modulating and feeding the RF signals
to the antenna
Base Station Controller(BSC)
• Monitors and controls over several BTSs
• Reallocation of frequencies among BTSs
• Time-delay measurements of received signals from the MS
• Providing an interface to the Operations and Maintenance Center for the
BSS

14. Cellular Structure
In mobile communication, the covering area of an operator is divided
into cells. A cell corresponds to the covering area of one BTS.

15. Frequency Reuse
Frequency reusing is the concept of using the same radio
frequencies within a given area, that are separated by considerable distance,
with minimal interference, to establish communication. Cluster 4 & 7 shown
below.

16. Handover
Inter BTS handover occurs when the mobile moves out of the
coverage area of one BTS and enters coverage area of another controlled by
the same BSC.

17. Call Drop
Termination of call due to technical reasons, before the speaking
parties had finished their conversational and before one of them had hung
up. The Telecom Regulatory Authority of India (TRAI) has announced a
compensation of Rs 1 for every call up to a maximum of three calls everyday
effect from January 1, 2016.
Reason behind call drop.
• Going out of coverage area.
• Obstacle in the way.(Building, Mountain etc.)
• Overload of cell tower.
• Poor handover

18. Roaming
Roaming enables a mobile subscriber to
automatically make & receive voice calls, send &
receive data or access other services when
travelling outside the geographical coverage
area of their home network.
Types of roaming.
• National roaming
• International roaming

19. Cell Global Identity(CGI)
Cell Global Identity(CGI) is a globally unique identifier for a Base
Transceiver Station in mobile phone networks.
It consists of four parts:
• Mobile Country Code (MCC) ---- 3 digits
• Mobile Network Code (MNC) ---- 2 digits
• Location Area Code (LAC) ---- Range 1 to 65536
• Cell Identification (CI) ---- Range 1 to 65536
Example: 404-76-60001-50001

20. Network Switching Subsystem(NSS)
• Mobile Switching Center(MSC)
• Visitor Location Register(VLR)
• Gateway Mobile Switching Center(GMSC)
• Home Location Register(HLR)
• Authentication Center(AuC)
• Equipment Identity Register(EIR)

21. Mobile Switching Center(MSC)
Function of MSC
• Switching & call routing
• Charging
• Service provisioning
• Communicating with HLR
• Communicating with VLR
• Communicating with other MSCs
• Control of connected BSCs

22. Visitor Location Register(VLR)
• It is a part of MSC
• Stores temporary location data of a mobile
• Controls mobile roaming in its area
• Reduces number of queries to HLR
• Passing location information to HLR

23. Home Location Register(HLR)
HLR stores permanent data of mobile
subscriber. Data stored in HLR are
• Subscription type(Postpaid/Prepaid)
• Outgoing call(Local/STD/ISD)
• Roaming facility(National/International)
• SMS subscription
• Data Subscription
• Current location of a Mobile

24. Authentication Center(AuC)
The AuC is a register used for security for
security purposes. It provides the parameters
needed for authentication and encryption
functions. It is used to verify the user’s identity.
• It is a part of HLR
• Protects against intruders in air interface

25. Authentication & Ciphering

26. Equipment Identity Register(EIR)
EIR is a register used for security propose.
It contains information about the mobile
handset.
• Database that is used to track handsets using
the IMEI(International Mobile Equipment
Identity) number.
• Made up of three subscriber classes: White
List, Black List & Gray List
• Only one EIR per PLMN

27. Serving GPRS Support Node(SGSN)
SGSN is the main component of GPRS
network which handels all packet data within
the network.
Function of SGSN
• Mobility management
• Authentication
• Charging information

28. Operation & Maintenance Subsystem
Function of O&M subsystem
• Monitoring & control of network.
• Configuration management
• Fault report & alarm handling
• Performance supervision
• Storage of software & data

29. Intelligent Network(IN)
Intelligent Network platform is used to
manage & control prepaid mobile services.
It is stores…
• Plan
• Validity
• Balance
• Data & Voice balance
• SMS balance

30. Billing System
Billing System is used to manage & control
postpaid mobile services.
Function of Billing System
• Provisioning of new customer
• Provisioning of outgoing call
• Provisioning of SMS & data service
• Provisioning of Roaming

31. SMS Center(SMSC)
The Short Message Service Center(SMSC) is responsible for delivery
of short messages(SMS). SMSC stores the messages and tries to deliver the
message.
The tasks of an SMSC can be described as
• Reception of text messages(SMS) from mobile users
• Storage of text messages
• Delivery of text messages (SMS) to mobile users
• Maintenance of unique time stamps in text messages
Type of SMS
• Transactional
• Non-Trasactional

32. 5G Technology

33. Internet of Things
The Internet of Things or IoT, refers to the crores of physical devices
around the world that are now connected to the internet, all collecting and
sharing data.
A lightbulb, fan, AC, fridge etc that can be operated using a smartphone
app is an IoT device. An IoT device could be as simple as a child's toy or as
serious as a driverless truck. At an even bigger scale, smart cities projects
with sensors help us to manage street light, traffic signals, CCTV cameras in a
efficient way.

34. Artificial intelligence
Artificial intelligence (AI) is intelligence demonstrated by
machines, unlike the natural intelligence displayed by humans
and animals, which involves consciousness and emotionality.
Part of AI are machine learning & data mining.
Machine learning (ML) is the study of computer algorithms that
improve automatically through experience.
Data mining is a process of discovering patterns in large data sets
involving methods at the intersection of machine learning,
statistics, and database systems.

35. ITI, Phulbani