modul 8_mobility_management [compatibility mode]

8/13/2019 Modul 8_Mobility_Management [Compatibility Mode]

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Wireless Communication Systems

Modul 8 Mobility Management

Faculty of Electrical and CommunicationInstitut Teknologi Telkom

Bandung 2012Modul 8 Mobility Management


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Universal Telecommunication Platform

Copper Cable

Fiber Optic

MSC

PSTN

SSF

SSFHLR

T M N

ACCESSNETWORK

CORE NETWORKSERVICEPLATFORM

USERENVIRONMENT


Coaxial Cable

W L L

Satellite

SDH

ISDN

ATM

I P

SSF

SSF

SSF

SSF

SCP

SMP

SCECellular

Satellite

Phone


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Communication Protocol

Rules and procedures to determine theformat and transmission of data

Packet structure of the data transmitted or thecontrol commands that manage the session


pro oco su e suc as s ma e up oseveral levels of functionality OSI Model


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Network Management Functions

1. Fault Management

2. Configuration Management3. Performance Management

4. Securit Mana ement


5. Accounting Management


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TMN & Telecommunication Networks

Data Communications

TMN

TMN Interfaces

TMN Interfaces

OperationsSystem

OperationsSystem

OperationsSystem

OperationsSystem

WorkStation

WorkStation

WorkStation


Network

TMN Interfaces

NetworkElement NetworkElement NetworkElement

TMN FOCUS: Communication of Management Information


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TMN Logical Layered Architecture (M.3010)

ServiceManagement

BusinessManagement

Enterprise view Revenue and account management Marketing & human resource planning

Contacts with customers & svc providers Service orders, complaints, & billing Quality of service

q

q

OSF

OSF


Single DomainStrategies

Strategies

ElementManagement

etworManagement

NetworkElements

End-to-end network view of all NEs & links

NE view or a sub-network view Data collection

Network resource functionality

q

q

NEF

OSF

OSF: Operations System Function, NEF: Network Element Function


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Mobility Management

Each generation of Wireless Mobile Network has different mechanismsfor Mobility Management.

Network support of subscriber mobility requires registration,authentication, paging, roaming, radio resource managementandexcess channel capacity.

Mobility Management focuses on registration, authentication,paging and roaming processes.

Radio Resource Management focuses on the networks ability toallocate radio access network resources.


Mobility Management transitioned from proprietary processes forvoice delivery services to open standards supporting voice andhigh speed data delivery services.

The most significant trends are migration to global roaming, enhancedsecurity, distribution of mobility management between core network

and radio access network and optimal use of network resources forregistration and paging. Radio Resource Management transitioned from simplistic RSSI

switching criteria to switching based on sophisticated signal qualityassessments and assumption of some mobility managementresponsibilities.


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PLMN Architecture



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Mobility Management

The base stations provide network access via a radiointerface for mobile subscribers.

The MSC manages base stations, consults PLMN

databases to establish subscriber access rights, routesmobile traffic and serves as a gateway to external

networks.


The HLR, VLR, AUC and EIR are PLMN databases, whichcontain subscriber profiles, location, encryption codesand equipment data.

Call establishment and connection maintenance are

fundamental services required by all telephone networks.


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Mobility Management

Mobility management is the ability of a PLMN to orchestrate callsfor its subscribers and radio management maintains the callregardless of the mobility of the subscribers.

PLMNs must track and dynamically route calls to its subscribers in

a transparent fashion. Locating, authenticating and tracking mobile subscribers are the

main functions of mobility management.


location. Paging process notifies mobile subscribers about incoming calls.

Authentication establishes the mobile stations right to accessnetwork services.

Roaming allows authorized mobile subscribers to use networksother than their home PLMN.

Radio Resource Management (RRM) consists of signal qualityassessments, base station selection and switching.


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Network Requirement for Mobility Management



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Registration and Paging

Registration updates the home PLMNs HLR andserving VLR databases with location information

for authorized mobile subscribers. The network operator uses the mobile subscribers

registration information to optimize the delivery of


.

Registration frequency can streamline the pagingprocess and minimize the size of VLR databases.


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Authentication

Mobile stations registering in an unknown networkinvoke an authentication process.

The network solicits unique identifiers from the

mobile station and passes the information to theHLR.

The HLR processes the information with the AUC


and the EIR. The mobile stations subscription and equipment

status is established and provided to the network.

If the status is valid, the network issues encryptioninformation and permits access. If the status isinvalid, the network denies access.


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Authentication

Authentication is sophisticated and uses the A3 algorithm.

Every new GSM subscriber receives a SubscriptionAuthentication Key (Ki) with the International Mobile

Subscriber Identifier (IMSI). The Ki is confidential andsecure. It is stored on the SIM and in the AUC.

During Authentication, the network issues a RandomNumber RAND . Both the mobile station and the network


derive a Signature Response (SRES) from a calculationwith the Ki and the RAND.

The mobile station transmits its SRES to the network forcomparison with the AUCs calculated value of SRES. If

they match, the mobile station receives network accessand encryption information. If they do not match, thenetwork denies access.


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Roaming

Roaming is the ability to access services from anetwork other than a home network.

Registration, authentication and paging processesmust be capable of supporting subscribers inforeign networks.


Agreements between network operators arerequired as well.


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Radio Resource Management

The most vulnerable part of a PLMN is the signalquality between an authorized mobile subscriberand its serving base station.

Distance between antennas and interference


.

Frequency hopping and RF transmit power levelcontrols mitigate interference issues.

Handoffs, base station resource switching, mitigate

distance related signal attenuation, traffic overloadsand persistent interference.


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Handoff

All handovers are hard. GSM networks support Intracell and Intercellhandovers within a common PLMN.

Handovers occur due to the following reasons:

1.) Signal quality between the mobile station and the base station

deteriorates indicated by excessive errors or low values of RSSI.2.) Distance between the mobile station and the base station exceeds a

predetermined limit

3. Cell traffic load mana ement


4.) Maintenance The wealth of standardization at every level in the architecture

expedites information transfer between network elements. Network

decision execution times are 5 to 10 times faster than AMPS for

handovers. The network architecture is an excellent implementationof 2G concepts and a foundation for future generations.


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Handoff and RSSI



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Handoff Scenario

The majority of handoffs support calls as mobilestraverse cell or sector boundaries.

Handoff processes are required for each of the following

scenarios :

1.) Crossing cell boundaries within a MSCs service area

-


2.) Crossing cell boundaries between MSCs (Inter-MSC)

3.) Crossing cell boundaries between different network

operators (Roaming)

4.) Crossing sector boundaries within a cell (Intra-cell)

5.) Switching channels to circumvent persistent

interference


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Handoff Scenario



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GSM Architecture



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GSM Protocol



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Layer 3 Protocol

Layer 3 provides Radio Resource (RR), MobilityManagement (MM), and Connection Management (CM)functions.

RR manages all air interface procedures such asfrequency selection, cell choice,handovers, signalquality assessments, channel assignment requests


an encryp on ecryp on sync ron za on.

MM is responsible for issuing TMSIs, finding the mobilestation, tracking the mobile station, IMSI attach/detach,

mobile station recognition, subscription verification and

protecting subscriber identity. CM is responsible for call setup and termination.


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Registration and Paging

Registration and paging processes benefit from

well-defined service areas, which have

internationally unique designations.

Cells are grouped together to form Location Areas

and are represented by Location Area Indicators


.

LAIs are globally unique and include country,

mobile network and location area codes.

All individual cells have global identifiers, whichspecify their LAI and Cell Identifier (CI)


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GPRS Architecture



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SGSN and GGSN

The Serving GPRS Support Node (SGSN) routes allmobile station packet traffic, performs logical linkmanagement, supports the mobile station attach /detachprocess and authenticates mobile stations.

Subscriber profiles and location information is stored in theSGSNs location register.

SGSNs serve a rou of cells Routin Area within a


location area. The Gateway GPRS Support Node (GGSN) is a protocol

converter and it interfaces the GPRS network to externalpacket data networks. It transforms GPRS traffic to the

packet data format of the external network, readdresses,and routes external packets terminating in the GPRSnetwork to the appropriate SGSN.


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GPRS Protocol



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GMM and SM

GPRS Mobility Management (GMM) and Session Management(SM) perform security processes, GPRS Attach / Detachprocedures, routing area updates and protocol data packetcontext activation.

GPRS implements mobility management with Idle, Ready andStandby states.

The Idle state indicates that the GPRS network is not aware of


.

The Standby state indicates that the GPRS network knows thesubscriber and its routing area.

The Ready state indicates that GPRS network knows thesubscriber, its cell location and is exchanging packets at will.

Attach /Detach processes register and deregister mobileterminals with the GPRS network. A successful attachment tothe GPRS network transitions a mobile station from the Idlestate to the Ready state.


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GPRS MM Model


W CDMA N k


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W-CDMA Network



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W-CDMA Control Plane Protocol

RRC

GMM

/SM

/SMS

GMM

/SM

/SMS

GTP-CRelay GTP-C


RF

MAC

RLC

RF

MAC

RLCRRC

ATM

Sign

Bearer

SCCPRANAP

Layer 1

IP

AAL5ATM

Sign

Bearer

SCCP

AAL5

Layer 2

Layer 1

IP

Layer 2

UuUE RNC SGSN GGSNIu Gn


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W-CDMA User Plane Protocol

PDCP

Appl

Relay

IP,PPP

Relay

IP,PPP


RF

MAC

RLC

RF

MAC

RLCPDCP

ATM

UDP/IPGTP-U

AAL5

Layer 1

Layer 2

UuUE RNC SGSN GGSNIu Gn

UDP/IPGTP-U

ATM

UDP/IPGTP-U

AAL5

Layer 1

Layer 2

UDP/IP

M bilit M t


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Mobility Management

Registration, authentication and pagingactivities are determined by mobility managementstates. Two different three state models are used

for circuit and packet switched mobilitymanagement.


-Idle, MM-Connected and MM-Detached states.

Packet switched mobility management uses PMM-

Idle, PMM-Connected and PMM-Detached states.

The mobility management states are indicators of

mobile station location resolution.

CS MM


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CS-MM


PM MM


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PM-MM


CDMA2000 Network


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CDMA2000 Network

1 2 34 5 6

7 8 9* 8 #

1 2 3

4 5 67 8 9* 8 #

PSTN

3 C om

HLRSMS-SC

M SC

T1/E1

T1/E1

T1/E1

T1/E1

BSC


1 2 34 5 6

7 8 9* 8 #

1 2 34 5 6

7 8 9* 8 #

R outer Router

PDN

Internet

Fire Wall

PDSN

A AA

Home Agent

T1/E1

T1/E1

T1/E1

T1/E1

T1/E1

B SC

CDMA2000 L i P t l


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CDMA2000 Layering Protocol




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MM Scheme Comparison


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modul 8_mobility_management [compatibility mode]

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