GSM (GLOBAL SYSTEM FOR
MOBILE COMMUNICATION)
PRESENTATION PLAN
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INTRODUCTION
CELLULAR MOBILE COMMUNICATIONS
GSM NETWORK ARCHITECTURE
MOBILITY AND TRAFFIC MANAGEMENT
GSM PROTOCOLS
HISTORY OF WIRELESS
COMMUNICATION
•1982 CEPT start to develop cell structure
•1986 Basic GSM radio tarnsmission technics
chosen
•1988 The Telecommunication Standarts
Instute define GSM
•1989 Explanation is finished for GSM
Generation 1
•1991 First call in GSM
• 1992 First GSM Network in the world
• 1993 GSM Network is reached 32
• 1994 First GSM Network in Africa,
• 1995 GSM Network is reached 117
• 1998 120 Million User on the World
• 1999 First GPRS
• 1998 480 Million User on the World
• 2003 863 Million User on the World
• 2004 3G World Congress
• 2007 2.4 Billion user on the world
1st Generation
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Start to use in 1989
Call forwarding
All calls
No answer
Engaged
Unreachable
Outgoing calls barring
Incoming calls barring
Global roaming
2nd Generation
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Finished process in 1995
SMS(Short Message Services)
Multi Party Calling
Call holding
Call waiting
Mobile data service
Mobile fax service
Call line identity
Advice of charging
Cell broadcast
2+
Generation
• Start to use in 1998
• Services developed
• DECT and GSM
• VPN(Virtual Private Network)
• Packet Radio
• SIM development
• Enjoyable services
Mobile Radio
Cellular Mobile
Communications
Definition
– A cellular mobile comms. system uses a large number of
low-power wireless transmitters to create cells
– Variable power levels allow cells to be sized according to
subscriber density and demand within a particular region
– As mobile users travel from cell to cell, their conversations
are handed off between cells
– Channels (frequencies) used in one cell can be reused in
another cell some distance away
Mobile Comms. Principles
– Mobile uses a separate, temporary radio channel to
talk to the cell site
– Cell site talks to many mobiles at once, using one
channel per mobile
– Channels use a pair of frequencies for communication
• The forward link for transmitting from the cell site
• The reverse link for the cell site to receive calls from the
users
Mobile Comms. Principles
• Radio energy dissipates over distance, so
mobiles must stay near the base station to
maintain communications
• Basic structure of mobile networks
includes telephone systems and radio
services
Mobile Comms. Principles
• Where mobile radio service operates in a closed
network and has no access to the telephone system,
mobile telephone service allows interconnection to the
telephone network
Mobile Comms. Principles
• Radio energy dissipates over distance, so
mobiles must stay near the base station to
maintain communications
• basic structure of mobile networks
includes telephone systems and radio
services
Mobile Systems Using Cells
• The cellular concept employs variable lowpower levels
– cells are sized according to the subscriber
density and demand in a given area
• Cells can be added to accommodate
population growth
Mobile Systems Using Cells
• As with early mobile radio systems, the base
station communicates with mobiles 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
Mobile System using
Cellular architecture
Cellular System Architecture
• In modern cellular telephony, rural and
urban regions are divided into areas
according to specific provisioning
guidelines
• Deployment parameters, such as amount
of cell-splitting and cell sizes, are
determined by engineers experienced in
cellular system architecture
Cells
• A cell is the basic geographic unit of a
cellular system
– The term cellular comes from the honeycomb shape
of the areas into which a coverage region is divided
– Cells are base stations transmitting over small
geographic areas that are represented as hexagons
– Size varies depending on the landscape
Clusters
• A cluster is a group of cells
– No channels are reused within a cluster
A seven Cell Cluster
Cell Splitting
• Allows urban centres to be split into as many
areas as necessary for acceptable service levels
in heavy-traffic regions, while larger, less
expensive cells can be used to cover remote
rural regions
GSM NETWORK ARCHITECTURE
OPEN INTERFACES OF GSM
• Network Switching Subsystem(NSS)
• Base Station Subsystem(BSS)
• Network Management Subsystem(NMS) or
Operation and Support Subsystem(OSS)
• They connect with Air,A,O&M interfaces
MOBILITY FUNCTIONS
• Registration and Database
• SIM (The Subscriber Identity Module)
• Location Update
Registration and Database
• HLR (Home Location Register)
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It includes all permanent user’s information
VLR(Visitor Location Register)
It includes temporary user’s information
according to user’s position
MSC (Mobile Switching Center)
It is an integrated structure with phone
exchange(Santral)
Databases of GSM Network
SIM
• It includes numbers which provide
definition of user for network
• It also includes reachable networks list
Location Update
Procedure of Location Update
SET UP CALLS IN GSM NETWORK
• +90 400 398 0102
• MSISDN = CC + NDC + SN
• CC : Country Code
• NDC : National Destination Code
• SN : Subscriber Number
• GMSC : Gateway Mobile Services
Switching Center
REACH CALLS FROM PSTN TO GSM
NETWORK
GUİDE CALL TO GSM NETWORK
CONTENT OF HLR
• MSISDN
• IMSI
• They provide the right call, right service
IMSI = MCC+MNC+MSIN
MCC = Mobile Country Code
MNC = Mobile Network Code
MSIN = Mobile Sucscriber Identification Number
• MSRN (Mobile Station Roaming Number)
MSRN = CC + NDC + SN
CC : Country Code
NDC : National Destination Code
SN : Subscriber Number
2.MSC wants to MSRN FROM HLR(Left Photo)
HLR gives MSRN to MSC for startin call(Right Photo)
PROCEDURE OF CALL SET UP
Procedure
• The number is MSISDN
• PSTN central analyse the MSISDN and
connect to GMSC
• GMSC analyse the MSISDN and send
message HLR
• HLR control databases and thrust into the
user’s location
• HLR query MSC/VLR
• MSC/VLR produce MSRN
• MSC/VLR send MSRN to HLR, HLR send it
to GMSC
• GMSC realise MSC/VLR for forwarding call
• MSC/VLR gets MSRN and starts to call
• MSC/VLR starts to paging process in
location area.The user is found with
paging signal and call set up
PROCEDURE OF CALL SET UP
FROM MOBİLE USER
HANDOVER
• TWO REASON
• When The Radio Signal’s quality and
power decreases to necessary scores, the
connection deliver to more powerful cell
• When The Trraffic Capacity approaches to
maximum , the connection deliver to less
density of traffic cell
SIGNALS AND PROTOCOLS
• STANDART MESSAGES
• SENDER WANTS TO SERVICE
• OPERATOR ASK THAT YOU WANTS TO TALK
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,BUT WHICH USER
OPERATOR CONNECT TO RECEIVER
WHEN THE RECEIVER REPLIES TO CALL ,THE
CALL STARTS
WHEN THE RECEIVER OR SENDER CLOSE THE
PHONE , THE OPERATOR FINISH CONNECTION
TO EACH OTHER
PROCEDURE OF SIGNALS
COMMON CHANNEL SIGNALLING
SYSTEM
• MTP(MASSAGE TRANSFER PART)
• TUP(TELEPHONE USER PART)
• SSCP(SIGNALLING CONNECTION AND
CONTROL PART)
MTP(MASSAGE TRANSFER PART)
PHYSICAL CONNECTION
It includes data links and their propertie
DATA LINK CONTROL
It helps to transfer messages between
component of network perfectly
NETWORK LAYER
It provides to transfer messages between
component of network
TUP(TELEPHONE USER PART)
• User’s identification
• Who get this messages or signals
• Who make a process this signal
• TUP,NUD,ISUP help to set up calls and
they make same task
SIGNALLING CONNECTION AND
CONTROL PART
• It provides virtual connections
• It guarentee to transfer messages from
every signals point to every signals point
secure
• It provides multi-point communication
Briefly
• MTP transmit messages
• TUP use this messages.It sets up
calls,manages calls and finishes calls
• SCCP create virtual connections and
multi-point communication
OTHER SS7 APPLICATION IN GSM
NETWORK
• BSSAP(Base Station Subsystem Application
Part)
• MAP (Mobile Application Part)
• TCAP (Transaction Capabilities Application
Part)
BASE STATION SUBSYSTEM
APPLICATION PART
It provide MSC-BSC and MSC-MS communication
SCCP service is required
MOBILE APPLICATION PART
• Before the call is guided to HLR, MSRN is wanted from
HLR , so the another protocol is added SS7 which is
called MAP
• It provides to communicate between Component of
Network Switching Subsystem
• MAP only uses for non-call-related messaging in MSCMSC communication
TCAP (Transaction Capabilities
Application Part)
It manages to communication
It likes a secretary
in MAP
SS7 LAYER IN COMPONENT OF
GSM
• SET OF PROTOCOL IN MSC
• SET OF PROTOCOL IN HLR
• SET OF PROTOCOL IN BSC
SET OF PROTOCOL IN MSC
MSC control calls
• MTP is required for all components which
works with SS7
• TUP/ISUP is reuired for calls
• It has all components of layers in SS7
SET OF PROTOCOL IN HLR
• It does not intersest control of calls, so
TUP/ISUP is not necessary
• It does not connect directly, so BSSAP is
not necessary
SET OF PROTOCOL IN BSC
• BSS AP is only required
• SCCP services are necessrary
• Consequently MTP is required
SS7 PROTOCOLS IN DIFFERENT
NETWORK COMPONENTS
Next table show functions of SS7
Protocols for all components of
GSM network
MSC
BSC
HLR
MTP
It provides to
transfer the
messages of SS7
between different
network
components
It provides to
transfer the
messages of SS7
between different
network
components
It provides to transfer the messages of SS7
between different network components
TUP/ISU
P
It provides to set
up, manage and
control the calls
No exist
No exist
SCCP
It provides
connectionless
communication
and virtual
connections
It provides virtual
connection
between MSC and
Connectionless Communication
BSSAP
It provides GSM
communication
between BSC and
MS
MSC and GSM
communication
No exist
MAP
It provides basic
communication
between HLR and
other MSC
No exist
It provides basic communication between MSC and
HLR
TCAP
It provides to
connect service to
MAP
No exist
It provides to connect service to MAP
INAP
It provides
communication
via Intelligent
No exist
It provides communication via Intelligent Network
MS