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ECET 581/CPET/ECET 499ECET 581/CPET/ECET 499 Mobile Computing Technologies & AppsMobile Computing Technologies & Apps

Mobility Management Mobility Management 1 of 21 of 2

Lecture 4Lecture 4

Paul I-Hai Lin, Professor Paul I-Hai Lin, Professor Electrical and Computer Engineering TechnologyElectrical and Computer Engineering Technology

Indiana University-Purdue University Fort WayneIndiana University-Purdue University Fort Wayne

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Mobility ManagementMobility Management Mobility ManagementMobility Management

• Mobility management related tasksMobility management related tasks• Location managementLocation management• Handoff managementHandoff management

Location Management Principles & techniquesLocation Management Principles & techniques• Location Registrars (databases)Location Registrars (databases)• OperationsOperations

Search operationSearch operation Update operationUpdate operation

Location Management Case StudiesLocation Management Case Studies SummarySummary

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Mobility Management Mobility Management

Mobility Management

Location Management

Handoff Management

Service Types

TelephonyData/

InformationMultimedia?

Mobile Device n

Mobile Device m

Network Insfrastructure

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Mobile device m Mobile device m ↔ Mobile device n↔ Mobile device n Task 1. Determine Device m’s Location Task 1. Determine Device m’s Location

and Establish a Routeand Establish a Route• Its access point (AP) in the wireless networkIts access point (AP) in the wireless network• Base stations in cellular networks Base stations in cellular networks

Task 2. Handoff - when m device move Task 2. Handoff - when m device move out of the range of current AP, it out of the range of current AP, it established a connection with another APestablished a connection with another AP

Task 3. The connection/data packets are Task 3. The connection/data packets are routed correctly to new AP routed correctly to new AP

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Task 1: Location Management System & OperationsTask 1: Location Management System & Operations

Mobile Device n

Mobile Device m

Location Management System p

Mobile Nodes Location

Database

Mobile Nodes Location Information Location Registrars

Location Management System k

Mobile Nodes Location

Database

Mobile Nodes Location Information Location Registrars

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Task 1: Location Management System & Task 1: Location Management System & OperationsOperations• Location Registrars – databasesLocation Registrars – databases• Two OperationsTwo Operations

SearchSearch• Mobile Node m – Invoke the search operationMobile Node m – Invoke the search operation• Mobile Node n – Current Location UnknownMobile Node n – Current Location Unknown• Cost of Search: Finest Granularity, Coarser Granularity Cost of Search: Finest Granularity, Coarser Granularity

Update (Registration)Update (Registration)• Mobile Node n – Informs the system of its current Mobile Node n – Informs the system of its current

locationlocation• Frequency of update (never performed?, too frequent?)Frequency of update (never performed?, too frequent?)

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Task 1: Location Management System & Task 1: Location Management System & OperationsOperations

Cost of Search OperationsCost of Search Operations• The granularity and currency of location The granularity and currency of location

informationinformation Finest granularityFinest granularity

• Maintained in a CellMaintained in a Cell• Requires a mobile node to update its location whenever Requires a mobile node to update its location whenever

it move from one cell to anotherit move from one cell to another Coarser granularityCoarser granularity

• In an area consisting of certain number of contiguous In an area consisting of certain number of contiguous cellscells

• Search cost ↑, because a large number of cells need to Search cost ↑, because a large number of cells need to be paged to obtain the exact location (cell) of the be paged to obtain the exact location (cell) of the mobile node each time a call needs to be establishedmobile node each time a call needs to be established

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Task 2 Handoff Task 2 Handoff • Ensure the mobile node remains connected Ensure the mobile node remains connected

while moving from one cell to anotherwhile moving from one cell to another• Or In-transit packets can be routed correctlyOr In-transit packets can be routed correctly

SubtasksSubtasks1. Deciding when to handoff to a new AP1. Deciding when to handoff to a new AP2. Selecting a new AP from several APs in the 2. Selecting a new AP from several APs in the

vicinityvicinity3. Acquiring resources: channels3. Acquiring resources: channels4. Informing Old AP to reroute data packets; 4. Informing Old AP to reroute data packets;

and send state information and send state information

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Handoff Management SubtasksHandoff Management Subtasks1.1. Deciding when to handoff (switch) to a new APDeciding when to handoff (switch) to a new APHandoff Decision can be initiated/controlled:Handoff Decision can be initiated/controlled:• Mobile-controlled HandoffMobile-controlled Handoff• Network-controlled HandoffNetwork-controlled HandoffDecision Factors:Decision Factors:• Signal quality or quality of wireless communication Signal quality or quality of wireless communication

(Signal-to-Noise ratio)(Signal-to-Noise ratio)• The Load of current AP is high The Load of current AP is high → Switch to a lightly → Switch to a lightly

loaded APloaded APSmooth Operation:Smooth Operation:• Code Division Multiple Access – permit smooth Code Division Multiple Access – permit smooth

handoffshandoffs• Multiple base stations can be in communication Multiple base stations can be in communication

before selecting a base stationbefore selecting a base station

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Handoff Management SubtasksHandoff Management Subtasks2. Selecting a new AP from several APs in the vicinity2. Selecting a new AP from several APs in the vicinity

Deciding FactorsDeciding Factors• The SNR of the beacon signals from these APsThe SNR of the beacon signals from these APs• The anticipated region the mobile node is expected The anticipated region the mobile node is expected

to move toto move to• The availability of resource at the AP: The availability of resource at the AP:

Uplink & downlink channels of connection-Uplink & downlink channels of connection-oriented circuit-switched network oriented circuit-switched network

Address (such as IP) in a packet switched Address (such as IP) in a packet switched networknetwork

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Mobility Management Tasks Mobility Management Tasks (cont.)(cont.)

Handoff Management SubtasksHandoff Management Subtasks3. Acquiring resources: channels3. Acquiring resources: channels• Channel Allocation SchemesChannel Allocation Schemes

4. Informing old AP to reroute data packets; and send 4. Informing old AP to reroute data packets; and send state information state information

• Route several in-transit packets:Route several in-transit packets:• Connection-less traffic (UDP/IP data grams): the IP Connection-less traffic (UDP/IP data grams): the IP

address of the new AP as the destination addressaddress of the new AP as the destination address• Connection-oriented trafficConnection-oriented traffic

TCP/IP on the Internet: Quad-tuple(source IP address, TCP/IP on the Internet: Quad-tuple(source IP address, source port, destination IP address, destination port) source port, destination IP address, destination port)

Asynchronous Transfer Mode (ATM)Asynchronous Transfer Mode (ATM) Public Switched Telephone Networks (PSTN) Public Switched Telephone Networks (PSTN)