GSM

1. GSM (GLOBAL SYSTEM FORGSM (GLOBAL SYSTEM FOR
MOBILE COMMUNICATION)MOBILE COMMUNICATION)

2. PRESENTATION PLANPRESENTATION PLAN
• INTRODUCTIONINTRODUCTION
• CELLULAR MOBILE COMMUNICATIONSCELLULAR MOBILE COMMUNICATIONS
• GSM NETWORK ARCHITECTUREGSM NETWORK ARCHITECTURE
• MOBILITY AND TRAFFIC MANAGEMENTMOBILITY AND TRAFFIC MANAGEMENT
• GSM PROTOCOLSGSM PROTOCOLS

3. HISTORY OF WIRELESSHISTORY OF WIRELESS
COMMUNICATIONCOMMUNICATION
•1982 CEPT start to develop cell structure1982 CEPT start to develop cell structure
•1986 Basic GSM radio tarnsmission technics1986 Basic GSM radio tarnsmission technics
chosenchosen
•1988 The Telecommunication Standarts1988 The Telecommunication Standarts
Instute define GSMInstute define GSM
•1989 Explanation is finished for GSM1989 Explanation is finished for GSM
Generation 1Generation 1
•1991 First call in GSM1991 First call in GSM

4. • 1992 First GSM Network in the world1992 First GSM Network in the world
• 1993 GSM Network is reached 321993 GSM Network is reached 32
• 1994 First GSM Network in Africa,1994 First GSM Network in Africa,
• 1995 GSM Network is reached 1171995 GSM Network is reached 117
• 1998 120 Million User on the World1998 120 Million User on the World
• 1999 First GPRS1999 First GPRS
• 1998 480 Million User on the World1998 480 Million User on the World

5. • 2003 863 Million User on the World2003 863 Million User on the World
• 2004 3G World Congress2004 3G World Congress
• 2007 2.4 Billion user on the world2007 2.4 Billion user on the world

6. 1st Generation1st Generation
• Start to use in 1989
• Call forwarding
• All calls
• No answer
• Engaged
• Unreachable
• Outgoing calls barring
• Incoming calls barring
• Global roaming

7. 2nd Generation2nd Generation
• 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 chargingAdvice of charging
• Cell broadcastCell broadcast

8. 2+ Generation
• Start to use in 1998Start to use in 1998
• Services developedServices developed
• DECT and GSMDECT and GSM
• VPN(Virtual Private Network)VPN(Virtual Private Network)
• Packet RadioPacket Radio
• SIM developmentSIM development
• Enjoyable servicesEnjoyable services

9. Mobile RadioMobile Radio
Cellular MobileCellular Mobile
CommunicationsCommunications

10. DefinitionDefinition
– A cellular mobile comms. system uses a large number ofA cellular mobile comms. system uses a large number of
low-power wireless transmitters to create cellslow-power wireless transmitters to create cells
– Variable power levels allow cells to be sized according toVariable power levels allow cells to be sized according to
subscriber density and demand within a particular regionsubscriber density and demand within a particular region
– As mobile users travel from cell to cell, their conversationsAs mobile users travel from cell to cell, their conversations
are handed off between cellsare handed off between cells
– Channels (frequencies) used in one cell can be reused inChannels (frequencies) used in one cell can be reused in
another cell some distance awayanother cell some distance away

11. Mobile Comms. PrinciplesMobile Comms. Principles
– Mobile uses a separate, temporary radio channel toMobile uses a separate, temporary radio channel to
talk to the cell sitetalk to the cell site
– Cell site talks to many mobiles at once, using oneCell site talks to many mobiles at once, using one
channel per mobilechannel per mobile
– Channels use a pair of frequencies for communicationChannels use a pair of frequencies for communication
• The forward link for transmitting from the cell siteThe forward link for transmitting from the cell site
• The reverse link for the cell site to receive calls from theThe reverse link for the cell site to receive calls from the
usersusers

12. Mobile Comms. PrinciplesMobile Comms. Principles
• Radio energy dissipates over distance, soRadio energy dissipates over distance, so
mobiles must stay near the base station tomobiles must stay near the base station to
maintain communicationsmaintain communications
• BBasic structure of mobile networksasic structure of mobile networks
includes telephone systems and radioincludes telephone systems and radio
servicesservices

13. Mobile Comms. PrinciplesMobile Comms. Principles
• Where mobile radio service operates in a closedWhere mobile radio service operates in a closed
network and has no access to the telephone system,network and has no access to the telephone system,
mobile telephone service allows interconnection to themobile telephone service allows interconnection to the
telephone networktelephone network

14. Mobile Comms. PrinciplesMobile Comms. Principles
• Radio energy dissipates over distance, soRadio energy dissipates over distance, so
mobiles must stay near the base station tomobiles must stay near the base station to
maintain communicationsmaintain communications
• basic structure of mobile networksbasic structure of mobile networks
includes telephone systems and radioincludes telephone systems and radio
servicesservices

15. Mobile Systems Using CellsMobile Systems Using Cells
• The cellular concept employs variable low-The cellular concept employs variable low-
power levelspower levels
– cells are sized according to the subscribercells are sized according to the subscriber
density and demand in a given areadensity and demand in a given area
• Cells can be added to accommodateCells can be added to accommodate
population growthpopulation growth

16. Mobile Systems Using CellsMobile Systems Using Cells
• As with early mobile radio systems, the baseAs with early mobile radio systems, the base
station communicates with mobiles via astation communicates with mobiles via a
channelchannel
– The channel is made of two frequencies, one forThe channel is made of two frequencies, one for
transmitting to the base station and one to receivetransmitting to the base station and one to receive
information from the base stationinformation from the base station
Mobile System using
Cellular architecture

17. Cellular System ArchitectureCellular System Architecture
• In modern cellular telephony, rural andIn modern cellular telephony, rural and
urban regions are divided into areasurban regions are divided into areas
according to specific provisioningaccording to specific provisioning
guidelinesguidelines
• Deployment parameters, such as amountDeployment parameters, such as amount
of cell-splitting and cell sizes, areof cell-splitting and cell sizes, are
determined by engineers experienced indetermined by engineers experienced in
cellular system architecturecellular system architecture

18. CellsCells
• A cell is the basic geographic unit of aA cell is the basic geographic unit of a
cellular systemcellular system
– The termThe term cellularcellular comes from the honeycomb shapecomes from the honeycomb shape
of the areas into which a coverage region is dividedof the areas into which a coverage region is divided
– Cells are base stations transmitting over smallCells are base stations transmitting over small
geographic areas that are represented as hexagonsgeographic areas that are represented as hexagons
– Size varies depending on the landscapeSize varies depending on the landscape

19. ClustersClusters
• A cluster is a group of cellsA cluster is a group of cells
– No channels are reused within a clusterNo channels are reused within a cluster
A seven Cell Cluster

20. Cell SplittingCell Splitting
• Allows urban centres to be split into as manyAllows urban centres to be split into as many
areas as necessary for acceptable service levelsareas as necessary for acceptable service levels
in heavy-traffic regions, while larger, lessin heavy-traffic regions, while larger, less
expensive cells can be used to cover remoteexpensive cells can be used to cover remote
rural regionsrural regions

21. GSM NETWORKGSM NETWORK
ARCHITECTUREARCHITECTURE

22. OPEN INTERFACES OF GSMOPEN INTERFACES OF GSM
• Network Switching Subsystem(NSS)Network Switching Subsystem(NSS)
• Base Station Subsystem(BSS)Base Station Subsystem(BSS)
• Network Management Subsystem(NMS)Network Management Subsystem(NMS)
or Operation and Supportor Operation and Support
Subsystem(OSS)Subsystem(OSS)
• They connect with Air,A,O&M interfacesThey connect with Air,A,O&M interfaces

24. MOBILITY FUNCTIONSMOBILITY FUNCTIONS
• Registration and DatabaseRegistration and Database
• SIM (The Subscriber Identity Module)SIM (The Subscriber Identity Module)
• Location UpdateLocation Update

25. Registration and DatabaseRegistration and Database
• HLR (Home Location Register)HLR (Home Location Register)
It includes all permanent user’s informationIt includes all permanent user’s information
• VLR(Visitor Location Register)VLR(Visitor Location Register)
It includes temporary user’s informationIt includes temporary user’s information
according to user’s positionaccording to user’s position
• MSC (Mobile Switching Center)MSC (Mobile Switching Center)
It is an integrated structure with phoneIt is an integrated structure with phone
exchange(Santral)exchange(Santral)

26. Databases of GSM NetworkDatabases of GSM Network

27. SIMSIM
• It includes numbers which provideIt includes numbers which provide
definition of user for networkdefinition of user for network
• It also includes reachable networks listIt also includes reachable networks list

28. Location UpdateLocation Update

29. Procedure of Location UpdateProcedure of Location Update

30. SET UP CALLS IN GSMSET UP CALLS IN GSM
NETWORKNETWORK
• +90 400 398 0102+90 400 398 0102
• MSISDN = CC + NDC + SNMSISDN = CC + NDC + SN
• CC : Country CodeCC : Country Code
• NDC : National Destination CodeNDC : National Destination Code
• SN : Subscriber NumberSN : Subscriber Number
• GMSC : Gateway Mobile ServicesGMSC : Gateway Mobile Services
Switching CenterSwitching Center

31. REACH CALLS FROM PSTN TOREACH CALLS FROM PSTN TO
GSM NETWORKGSM NETWORK

32. GUİDE CALL TO GSMGUİDE CALL TO GSM
NETWORKNETWORK

33. CONTENT OF HLRCONTENT OF HLR
• MSISDNMSISDN
• IMSIIMSI
• They provide the right call, right serviceThey provide the right call, right service
IMSI = MCC+MNC+MSINIMSI = MCC+MNC+MSIN
MCC = Mobile Country CodeMCC = Mobile Country Code
MNC = Mobile Network CodeMNC = Mobile Network Code
MSIN = Mobile Sucscriber Identification NumberMSIN = Mobile Sucscriber Identification Number

34. • MSRN (Mobile Station Roaming Number)MSRN (Mobile Station Roaming Number)
MSRN = CC + NDC + SNMSRN = CC + NDC + SN
CC : Country CodeCC : Country Code
NDC : National Destination CodeNDC : National Destination Code
SN : Subscriber NumberSN : Subscriber Number
2.MSC wants to MSRN FROM HLR(Left Photo)2.MSC wants to MSRN FROM HLR(Left Photo)
HLR gives MSRN to MSC for startin call(Right Photo)HLR gives MSRN to MSC for startin call(Right Photo)

35. PROCEDURE OF CALL SETPROCEDURE OF CALL SET
UPUP

36. ProcedureProcedure
• The number is MSISDNThe number is MSISDN
• PSTN central analyse the MSISDN andPSTN central analyse the MSISDN and
connect to GMSCconnect to GMSC
• GMSC analyse the MSISDN and sendGMSC analyse the MSISDN and send
message HLRmessage HLR
• HLR control databases and thrust into theHLR control databases and thrust into the
user’s locationuser’s location
• HLR query MSC/VLRHLR query MSC/VLR

37. • MSC/VLR produce MSRNMSC/VLR produce MSRN
• MSC/VLR send MSRN to HLR, HLR sendMSC/VLR send MSRN to HLR, HLR send
itit to GMSCto GMSC
• GMSC realise MSC/VLR for forwardingGMSC realise MSC/VLR for forwarding
callcall
• MSC/VLR gets MSRN and starts to callMSC/VLR gets MSRN and starts to call
• MSC/VLR starts to paging process inMSC/VLR starts to paging process in
location area.The user is found withlocation area.The user is found with
paging signal and call set uppaging signal and call set up

38. PROCEDURE OF CALL SET UPPROCEDURE OF CALL SET UP
FROM MOBİLE USERFROM MOBİLE USER

39. HANDOVERHANDOVER
• TWO REASONTWO REASON
• When The Radio Signal’s quality andWhen The Radio Signal’s quality and
power decreases to necessary scores,power decreases to necessary scores,
the connection deliver to more powerfulthe connection deliver to more powerful
cellcell
• When The Trraffic Capacity approaches toWhen The Trraffic Capacity approaches to
maximum , the connection deliver to lessmaximum , the connection deliver to less
density of traffic celldensity of traffic cell

40. SIGNALS AND PROTOCOLSSIGNALS AND PROTOCOLS
• STANDART MESSAGESSTANDART MESSAGES
• SENDER WANTS TO SERVICESENDER WANTS TO SERVICE
• OPERATOR ASK THAT YOU WANTS TOOPERATOR ASK THAT YOU WANTS TO
TALK ,BUT WHICH USERTALK ,BUT WHICH USER
• OPERATOR CONNECT TO RECEIVEROPERATOR CONNECT TO RECEIVER
• WHEN THE RECEIVER REPLIES TO CALLWHEN THE RECEIVER REPLIES TO CALL
,THE CALL STARTS,THE CALL STARTS
• WHEN THE RECEIVER OR SENDER CLOSEWHEN THE RECEIVER OR SENDER CLOSE
THE PHONE , THE OPERATOR FINISHTHE PHONE , THE OPERATOR FINISH
CONNECTION TO EACH OTHERCONNECTION TO EACH OTHER

41. PROCEDURE OF SIGNALSPROCEDURE OF SIGNALS

42. COMMON CHANNELCOMMON CHANNEL
SIGNALLING SYSTEMSIGNALLING SYSTEM
• MTP(MASSAGE TRANSFER PART)MTP(MASSAGE TRANSFER PART)
• TUP(TELEPHONE USER PART)TUP(TELEPHONE USER PART)
• SSCP(SIGNALLING CONNECTION ANDSSCP(SIGNALLING CONNECTION AND
CONTROL PART)CONTROL PART)

43. MTP(MASSAGE TRANSFERMTP(MASSAGE TRANSFER
PART)PART)

44. PHYSICAL CONNECTIONPHYSICAL CONNECTION
It includes data links and their propertieIt includes data links and their propertie
DATA LINK CONTROLDATA LINK CONTROL
It helps to transfer messages betweenIt helps to transfer messages between
component of network perfectlycomponent of network perfectly
NETWORK LAYERNETWORK LAYER
It provides to transfer messages betweenIt provides to transfer messages between
component of networkcomponent of network

45. TUP(TELEPHONE USERTUP(TELEPHONE USER
PART)PART)

46. • User’s identificationUser’s identification
• Who get this messages or signalsWho get this messages or signals
• Who make a process this signalWho make a process this signal
• TUP,NUD,ISUP help to set up calls andTUP,NUD,ISUP help to set up calls and
they make same taskthey make same task

47. SIGNALLING CONNECTION ANDSIGNALLING CONNECTION AND
CONTROL PARTCONTROL PART

48. • It provides virtual connectionsIt provides virtual connections
• It guarentee to transfer messages fromIt guarentee to transfer messages from
every signals point to every signals pointevery signals point to every signals point
securesecure
• It provides multi-point communicationIt provides multi-point communication

49. BrieflyBriefly
• MTP transmit messagesMTP transmit messages
• TUP use this messages.It sets upTUP use this messages.It sets up
calls,manages calls and finishes callscalls,manages calls and finishes calls
• SCCP create virtual connections andSCCP create virtual connections and
multi-point communicationmulti-point communication

50. OTHER SS7 APPLICATION INOTHER SS7 APPLICATION IN
GSM NETWORKGSM NETWORK
• BSSAP(Base Station SubsystemBSSAP(Base Station Subsystem
Application Part)Application Part)
• MAP (Mobile Application Part)MAP (Mobile Application Part)
• TCAP (Transaction CapabilitiesTCAP (Transaction Capabilities
Application Part)Application Part)

51. BASE STATION SUBSYSTEMBASE STATION SUBSYSTEM
APPLICATION PARTAPPLICATION PART
It provide MSC-BSC and MSC-MS communicationIt provide MSC-BSC and MSC-MS communication
SCCP service is requiredSCCP service is required

52. MOBILE APPLICATION PARTMOBILE APPLICATION PART
• Before the call is guided to HLR, MSRN is wanted fromBefore the call is guided to HLR, MSRN is wanted from
HLR , so the another protocol is added SS7 which isHLR , so the another protocol is added SS7 which is
called MAPcalled MAP
• It provides to communicate between Component ofIt provides to communicate between Component of
Network Switching SubsystemNetwork Switching Subsystem
• MAP only uses for non-call-related messaging in MSC-MAP only uses for non-call-related messaging in MSC-
MSC communicationMSC communication

53. TCAP (Transaction CapabilitiesTCAP (Transaction Capabilities
Application Part)Application Part)
It manages to communicationIt manages to communication in MAPin MAP
It likes a secretaryIt likes a secretary

54. SS7 LAYER IN COMPONENT OFSS7 LAYER IN COMPONENT OF
GSMGSM
• SET OF PROTOCOL IN MSCSET OF PROTOCOL IN MSC
• SET OF PROTOCOL IN HLRSET OF PROTOCOL IN HLR
• SET OF PROTOCOL IN BSCSET OF PROTOCOL IN BSC

55. SET OF PROTOCOL IN MSCSET OF PROTOCOL IN MSC

56. MSC control callsMSC control calls
• MTP is required for all components whichMTP is required for all components which
works with SS7works with SS7
• TUP/ISUP is reuired for callsTUP/ISUP is reuired for calls
• It has all components of layers in SS7It has all components of layers in SS7

57. SET OF PROTOCOL IN HLRSET OF PROTOCOL IN HLR

58. • It does not intersest control of calls, soIt does not intersest control of calls, so
TUP/ISUP is not necessaryTUP/ISUP is not necessary
• It does not connect directly, so BSSAP isIt does not connect directly, so BSSAP is
not necessarynot necessary

59. SET OF PROTOCOL IN BSCSET OF PROTOCOL IN BSC

60. • BSS AP is only requiredBSS AP is only required
• SCCP services are necessrarySCCP services are necessrary
• Consequently MTP is requiredConsequently MTP is required

61. SS7 PROTOCOLS IN DIFFERENTSS7 PROTOCOLS IN DIFFERENT
NETWORK COMPONENTSNETWORK COMPONENTS

62. Next table show functions of SS7Next table show functions of SS7
Protocols for all components ofProtocols for all components of
GSM networkGSM network

63. MSCMSC BSCBSC HLRHLR
MTPMTP
It provides toIt provides to
transfer thetransfer the
messages of SS7messages of SS7
between differentbetween different
networknetwork
componentscomponents
It provides toIt provides to
transfer thetransfer the
messages of SS7messages of SS7
between differentbetween different
networknetwork
componentscomponents
It provides to transfer the messages of SS7It provides to transfer the messages of SS7
between different network componentsbetween different network components
TUP/ISUTUP/ISU
PP
It provides to setIt provides to set
up, manage andup, manage and
control the callscontrol the calls
No existNo exist No existNo exist
SCCPSCCP
It providesIt provides
connectionlessconnectionless
communicationcommunication
and virtualand virtual
connectionsconnections
It provides virtualIt provides virtual
connectionconnection
between MSCbetween MSC
and MSand MS
Connectionless CommunicationConnectionless Communication
BSSAPBSSAP
It provides GSMIt provides GSM
communicationcommunication
between BSC andbetween BSC and
MSMS
MSC and GSMMSC and GSM
communicationcommunication
No existNo exist
MAPMAP
ItIt pprovides basicrovides basic
communicationcommunication
between HLR andbetween HLR and
other MSCother MSC
No existNo exist It provides basic communication between MSCIt provides basic communication between MSC
and HLRand HLR
TCAPTCAP
It provides toIt provides to
connect service toconnect service to
MAPMAP
No existNo exist It provides to connect service to MAPIt provides to connect service to MAP
INAPINAP
It providesIt provides
communicationcommunication
via Intelligentvia Intelligent
No existNo exist It provides communication via Intelligent NetworkIt provides communication via Intelligent Network