mobile network architecturesuraj.lums.edu.pk/~cs5710s05/cs_cmpe_5710_slides...5/10/2006...
TRANSCRIPT
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 1
Mobile Network Architecture
MSC
PSTN
ISDN
Internet
Voice/Data
Voice
Data
HLRVLR
AC
EIRAbis
Um
MAPn
MAPn
MS
BTS A
MS
BSC
HLR- Home Location RegisterVLR - Visitor Location registerMSC - Mobile Switching CenterBSC - Base Station Controller BTS - Base Transceiver Station AC - Authentication CenterEIR - Equipment Identity Register
BTS
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 2
Mobile Networks - Interface Protocols
Um - Air Interface; between MS and BSAbis - BTS and BSCA - BSS (BTS AND BSC) and BSC MAP - MSC and Network,
or MSC and HLR, VLR, EIR
TCAPMAPn
SCCP
Q.931+ ISUPTUP
DTAP, BSSMAPSCCP
LAPDmQ.931+
LAPDQ.931+ MTP3 MTP3
MTP2 MTP2MTP1Radio Int. T1/E1 MTP1
Abis A MAPUm
MTP- Message Transfer PartSCCP - Signaling Connection Control PartTCAP - Transaction Capabilities Application PartLAPD - Link Access Procedure, DLAPDm - LAPD for mobileBSSMAP- BSS management partDTAP - Direct Transfer Application Part
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 3
Major Components in a Mobile Network
MS MS -- Mobile StationMobile Stationmobile transceivermobile transceiver
runs application, control and management functions over the runs application, control and management functions over the air interfaceair interface
BS BS -- Base Station = BTS Base Station = BTS BTS BTS -- Base Transceiver StationBase Transceiver Station
manages air interface between MS and BTSmanages air interface between MS and BTSSlave of MSCSlave of MSCCommunicates to MS on MSC instructionsCommunicates to MS on MSC instructionsResponsible for power management across the AI (air Responsible for power management across the AI (air interface)interface)frequency administration between the BS and MS and power frequency administration between the BS and MS and power control together is Radio Resource (RR) Managementcontrol together is Radio Resource (RR) Management
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 4
Major Components in a Mobile Network
MSC MSC -- Mobile Switching CenterMobile Switching CenterControl element of the Mobile Network. Responsible for:Control element of the Mobile Network. Responsible for:
Switching the calls to cellsSwitching the calls to cellsprovide backupsprovide backupsinterfacing with telephone or Data Networkinterfacing with telephone or Data Networkbilling informationbilling informationperformance testing, diagnostics and network managementperformance testing, diagnostics and network management
Connection Management (CM) functions are coordinated at Connection Management (CM) functions are coordinated at the MSCthe MSCMSC delegates some functions to BS or BSCMSC delegates some functions to BS or BSC
BSC BSC -- Base Station ControllerBase Station ControllerIf is used it controls BSIf is used it controls BSMay be coMay be co--located with BS or with MSClocated with BS or with MSC
typically with MSCtypically with MSC
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 5
Major Components in a Mobile Network
Typical responsibilities are call handover and RR Typical responsibilities are call handover and RR managementmanagement
in this case, BS is mainly a bank of wireless modemsin this case, BS is mainly a bank of wireless modems
Databases in Mobile NetworksDatabases in Mobile NetworksHLR HLR -- Home Location RegistryHome Location Registry
Each HLR is associated with a Cellular Service ProviderEach HLR is associated with a Cellular Service ProviderEach subscriber belongs to one HLR Each subscriber belongs to one HLR keeps track of each subscriberkeeps track of each subscriberstores information about the subscriberstores information about the subscriber
is it on the air or not, i.e., subscriber active or inactiveis it on the air or not, i.e., subscriber active or inactivewhat services the user is subscribed to what services the user is subscribed to accounting informationaccounting information
VLR VLR -- Visitor Location RegistryVisitor Location Registrykeeps track of the visiting MSkeeps track of the visiting MSBoth HLR and VLR know the location of the MS if not in the Both HLR and VLR know the location of the MS if not in the default territorydefault territory
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 6
Major Components in a Mobile Network
VLR informs the HLR when a visiting MS comes inVLR informs the HLR when a visiting MS comes inthis is handover related operationthis is handover related operation
HLR tells VLR about the subscriber info.HLR tells VLR about the subscriber info.
HLR and VLR are attached to MSC or BSC (if used)HLR and VLR are attached to MSC or BSC (if used)Operation of HLR and VLR is known as Operation of HLR and VLR is known as Mobility ManagementMobility ManagementAC AC -- Authentication ControlAuthentication Control
this database contains authentication and encryption this database contains authentication and encryption information for each subscriberinformation for each subscriberAC interacts with HLR and VLR while providing this serviceAC interacts with HLR and VLR while providing this service
EIR EIR -- Equipment Identity RegisterEquipment Identity RegisterInfo on MS Info on MS
manufacturermanufacturerconformance testingconformance testingmanufacturing factory identifiermanufacturing factory identifier
How to implementation of the these databasesHow to implementation of the these databases
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 7
Connection Management OperationsFixed phone dials a MSFixed phone dials a MSCall is routed to the gateway MSCCall is routed to the gateway MSCgateway MSC determines that it cannot route further so it asks fgateway MSC determines that it cannot route further so it asks for information to the HLRor information to the HLRThe HLR asks the VLR for verification and routing informationThe HLR asks the VLR for verification and routing informationVLR provides the routing info to HLR and it forwards it to MSCVLR provides the routing info to HLR and it forwards it to MSCGateway MSC routes the call to the terminating MSCGateway MSC routes the call to the terminating MSCTerminating MSC asks VLR to match the incoming call to the identTerminating MSC asks VLR to match the incoming call to the identity of the receiving ity of the receiving subscribersubscriberTerminating MSC sends the BS a paging request which relays the pTerminating MSC sends the BS a paging request which relays the page to the subscriber age to the subscriber and the call is completedand the call is completed
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 8
Mobility Management Operations
MS sends a location update request with its identification to thMS sends a location update request with its identification to the BS. The e BS. The message is routed to the new VLRmessage is routed to the new VLRThe new VLR sends the request to the visitorThe new VLR sends the request to the visitor’’s HLRs HLRHLR stores the new VLR for the user and then provides it the subHLR stores the new VLR for the user and then provides it the subscriber scriber informationinformationThe VLR sends the acknowledgement to the MSC through the new MSCThe VLR sends the acknowledgement to the MSC through the new MSC and the and the new MSnew MSHLR sends location cancellation message to the old VLR to clear HLR sends location cancellation message to the old VLR to clear the subscribers the subscribers data form its database.data form its database.
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 9
Use of Identifiers
Called party number is relayed to Gateway MSCCalled party number is relayed to Gateway MSCGateway MSC ask for the subscriber routing info from the HLRGateway MSC ask for the subscriber routing info from the HLRHLR contacts visited MSC and VLR about the subscriber locationHLR contacts visited MSC and VLR about the subscriber locationVLR sends the routing information about the subscriber back to HVLR sends the routing information about the subscriber back to HLR that send LR that send this info to the Gateway MSC. this info to the Gateway MSC. Gateway MSC routes the call directly to the MSC that is serving Gateway MSC routes the call directly to the MSC that is serving the subscriberthe subscriberInternal numbers may be used between MSCInternal numbers may be used between MSC’’s, HLR and VLRs, HLR and VLR
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 10
Relevant Protocols and Interfaces
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 11
Procedures on the Air Interface
NW MS
System AcquisitionPaging Request & Assignment
Service Request and Contention ResolutionAuthentication
Ciphering Mode SettingTransaction PhaseChannel Release
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 12
Procedures on the Air InterfaceSystem AcquisitionSystem Acquisition
happens on power onhappens on power onsearch for a control channelsearch for a control channelreceive and provide parametersreceive and provide parametersacquire timingacquire timingThe MS can now stay in idle state The MS can now stay in idle state
Paging Request and AssignmentPaging Request and Assignmentif a call is made to a MS, if a call is made to a MS,
NW sends paging requestNW sends paging requestMS responds MS responds NW provides sufficient information for control channels to useNW provides sufficient information for control channels to use
If MS makes a callIf MS makes a callon an access control channel, MS sends channel request messageon an access control channel, MS sends channel request messageif everything is OK, NW sends immediate assignment message if everything is OK, NW sends immediate assignment message identifying a dedicated channel for the serviceidentifying a dedicated channel for the service
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 13
Procedures on the Air Interface
Service request and contention resolutionService request and contention resolutionMS may be involved in contention resolution and send MS may be involved in contention resolution and send several messages for service request several messages for service request MS sends L2 SABM (Set Asynchronous Balanced Mode) MS sends L2 SABM (Set Asynchronous Balanced Mode) frame that may contains the service request message, CM frame that may contains the service request message, CM related, location update, or exchanging identifiers.related, location update, or exchanging identifiers.NW responds with UA (unnumbered acknowledgement) NW responds with UA (unnumbered acknowledgement) frame that contains the same message as the SABM frameframe that contains the same message as the SABM frameMS compares the UA with SABM MS compares the UA with SABM
if messages do not match, it leaves the channel, resolving if messages do not match, it leaves the channel, resolving contentioncontentionelse, it continueelse, it continuea random reference number is used for this operation so that a random reference number is used for this operation so that all MS are likely to send different reference numberall MS are likely to send different reference numberonly send nononly send non--confidential information to the NW that are used confidential information to the NW that are used in RR and MM functions of the networkin RR and MM functions of the network
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 14
Procedures on the Air Interface
AuthenticationAuthenticationAuthentication Request and Authentication Response Authentication Request and Authentication Response messagesmessagesNW send Areq message to the MS that includes info such as NW send Areq message to the MS that includes info such as keyskeysMS returns Ares message that contains the validation of the MS returns Ares message that contains the validation of the useruser’’s identitys identity
Ciphering mode settingCiphering mode settingCipher mode command, cipher mode completeCipher mode command, cipher mode completeTells the MS whether to use ciphering in the transaction Tells the MS whether to use ciphering in the transaction phase or not and what algorithm to use. phase or not and what algorithm to use. MS sends cipher mode complete messageMS sends cipher mode complete message
Transaction phaseTransaction phaseActual traffic flow such as voice call or data transfer Actual traffic flow such as voice call or data transfer
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 15
Procedures on the Air Interface
Channel releaseChannel releaseChannel release happens once the transactions are overChannel release happens once the transactions are overthe other side sends the channel release complete messagethe other side sends the channel release complete messageMS goes back to the idle modeMS goes back to the idle mode
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 16
GSM - MAP Interfaces
EIR
AC
HLR
VLR
VLR
MSC MSCMAP-E
MAP-B
MAP-D
MAP-C
MAP-H
MAP-F
MAP-G
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 17
GSM System - Protocol Architecture
MMDTAP, BSSMAP
TDMALAPDm
RR
T1/E1 or L1LAPDBTSM
MTP1MTP2MTP3SCCP
MTP1MTP2MTP3
CM
SCCP
Q.931+ ISUPTUP
Um Abis A MAPn
MMCM
TDMALAPDm
RR
T1/E1 or L1LAPDBTSM
BSSMAP, DTAP
MTP1MTP2MTP3
BTS BSC
Base Station System - BSS
MS MSC
To from other MSCs and networksTo from other
MSCs
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 18
TDMALAC
RR
AAL/ATM/PHYQ.SAAL LAC
BSM
SCCP
Um Abis A MAPn
MM
PHYLAC
RELAYQ.SAAL
RR
To from other MSCs
AAL/ATM/PHY
Q.2140MTP3CM BSMCM
CM BSCM
AAL/ATM/PHYQ.SAALQ.2140
MAP(HLR)
MTP3
TCAP -TCP/UDPConvergence
SCCP
PHYIP
TCP
AAL/ATM/PHYQ.SAAL
PHYLAC
RELAY
BSMCM
UDP
TCAP
APPLICATION
3rd Gen. Mobile Networks - IMT 2000
MS BTS BSC MSC
To from other MSCs and networks
HLR
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GSM Addresses and Identifiers
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GSM Addresses and Identifiers
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GSM Addresses and Identifiers
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GSM Addresses and Identifiers
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 23
GSM Channel Organization
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GSM Channel Organization
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GSM Channel Organization
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GSM Channel Organization
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GSM Channel Organization
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GSM Channel Organization
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GSM Channel Organization
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GSM Authentication
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GSM Encryption
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Location Update
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 33
Initial Channel Usage
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Call Establishment to MS
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Location Update Operation
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5/10/2006 CS-CMPE-5710: Mobile Wireless Networks 36
MS Originates the Call
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MS Receives the Call
Mobile Network ArchitectureMobile Networks - Interface ProtocolsMajor Components in a Mobile NetworkMajor Components in a Mobile NetworkMajor Components in a Mobile NetworkMajor Components in a Mobile NetworkConnection Management OperationsMobility Management OperationsUse of IdentifiersRelevant Protocols and InterfacesProcedures on the Air InterfaceProcedures on the Air InterfaceProcedures on the Air InterfaceProcedures on the Air InterfaceProcedures on the Air InterfaceGSM - MAP InterfacesGSM System - Protocol Architecture3rd Gen. Mobile Networks - IMT 2000GSM Addresses and IdentifiersGSM Addresses and IdentifiersGSM Addresses and IdentifiersGSM Addresses and IdentifiersGSM Channel OrganizationGSM Channel OrganizationGSM Channel OrganizationGSM Channel OrganizationGSM Channel OrganizationGSM Channel OrganizationGSM Channel OrganizationGSM AuthenticationGSM EncryptionLocation UpdateInitial Channel UsageCall Establishment to MSLocation Update OperationMS Originates the CallMS Receives the Call