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WHATISMOBILITY?

spectrum of mobility, from thenetworkperspective:

no mobility high mobility

mobile wireless user,

using same access

point

mobile user, passing

through multiple access

point while maintaining

ongoing connections

(like cell phone)

mobile user,

connecting/

disconnecting from

network using DHCP.

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Effects of mobility

Channel characteristics change over time and location

signal paths change

different delay variations of different signal parts

different phases of signal parts

quick changes in the power received

(short term fading)

Additional changes in

distance to sender

obstacles further away slow changes in the average power

received (long term fading)short term fading

long term

fading

t

power

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MOBILITY: VOCABULARY

home network: permanenthome of mobile(e.g., 128.119.40/24)

Permanent address:

address in home network,can always be used to

reach mobilee.g., 128.119.40.186

home agent: entity that will performmobility functions on behalf of

mobile, when mobile is remote

wide area

network

correspondent

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MOBILITY: MOREVOCABULARY

Care-of-address: address in

visited network.(e.g., 79,129.13.2)

wide area

network

visited network: network inwhich mobile currently resides(e.g., 79.129.13/24)

Permanent address: remains

constant (e.g., 128.119.40.186)

foreign agent: entity in

visited network that

performs mobility

functions on behalf of

mobile.

correspondent: wants to

communicate with

mobile

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MOBILITY: APPROACHES

Let routing handle it: routers advertise permanent address of

mobile-nodes-in-residence via usual routing table exchange.

routing tables indicate where each mobile located

no changes to end-systems

Let end-systems handle it:

indirect routing: communication from correspondent to mobile

goes through home agent, then forwarded to remote

direct routing: correspondent gets foreign address of mobile, sends

directly to mobile

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MOBILITY: APPROACHES

Let routing handle it: routers advertise permanent address of

mobile-nodes-in-residence via usual routing table exchange.

routing tables indicate where each mobile located

no changes to end-systems

let end-systems handle it:

indirect routing: communication from correspondent to mobile

goes through home agent, then forwarded to remote

direct routing: correspondent gets foreign address of mobile, sends

directly to mobile

not

scalable

to millions of

mobiles

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Routing and Mobility

Finding a path from a source to a destination

Issues

Frequent route changes

amount of data transferred between route changesmay be much smaller than traditional networks

Route changes may be related to host movement

Low bandwidth links

Goal of routing protocols decrease routing-related overhead

find short routes

find stable routes (despite mobility)

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Multi-Hop Wireless

May need to traverse multiple links to reach destination

Mobility causes route changes

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mobility causeslink breakage,

resulting in route

failure

TCP data and acks

en route discarded

Impact of Node Mobility

TCP sender times out.

Starts sending packets again

Route is

repaired

No throughput

No throughput

despite route repair

TCP throughput degrades with increase in mobility but not always

Larger route repair

delays are especially

harmful

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Effect of mobility on protocolstack

Application new applications and adaptations

service location, multimedia

Transport congestion and flow control

quality of service Network

addressing and routing

device location, hand-over

Link media access and security

Physical transmission errors and interference

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Limitations of the mobileenvironment

Limitations of the Wireless Network

limited communication bandwidth

frequent disconnections

heterogeneity of fragmented networks

Limitations Imposed by Mobility

route breakages

lack of mobility awareness by system/applications

Limitations of the Mobile Device

short battery lifetime

limited capacities


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Wireless LANs vs. Wired LANs

Destination address does not equal destinationlocation

The media impact the design

wireless LANs intended to cover reasonablegeographic distances must be built from basiccoverage blocks

Impact of handling mobile (and portable)stations Propagation effects

Mobility management

Power management

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HANDLING MOBILITYIN

WIRELESS SENSORAND

ACTOR NETWORKS

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ABSTRACT

In Wireless Sensor and Actor Networks (WSANs), the

collaborative operation of sensors enables the distributed

sensing of a physical phenomenon, while actors collect

and process sensor data and perform appropriate actions.

WSANs can be thought of as a distributed control system

that needs to timely react to sensor information with an

effective action. In this paper, coordination and

communication problems in WSANs with mobile actors

are studied.

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HOWIT WORKS?

First, a new location management scheme is proposed to

handle the mobility of actors with minimal energy

expenditure for the sensors, based on a hybrid strategy

that includes location updating and location

prediction.

Actors broadcast location updates limiting their scope

based on Voronoi diagrams, while sensors predict the

movement of actors based on Kalman filtering of

previously received updates.

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HANDLINGMOBILITYACROSS

WIFIAND WIMAX

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ABSTRACT Performance of wireless data networks can be

improved by integrating heterogeneous

networks.

Hence, emerging wireless Internet networks

consist of heterogeneous wireless networks

working in synergy.

WiFi and WiMAX are particularly interesting in theirability towards mobile data oriented networking, and a

scheme that enables mobility across these two wouldprovide several advantages to end-users, wirelessoperators as well as Wireless Internet Service Providers(WISPs).

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HOWIT WORKS?

In this work, we propose a novel, cost-effective and end-

user friendly mobility scheme.

Our approach does not require additional client software

to handle WiFi-WiMAX mobility, or hardware changes

in any of the network entities involved.

We demonstrate the feasibility of our solution by

developing an actual prototype.

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2.4.4 MOBILITY SUPPORT

In addition to fixed broadband access, WiMAX envisions fourmobility-related usage scenarios:

1. Nomadic: The user is allowed to take a fixed subscriberstation and reconnect from a different point of attachment.

2. Portable: Nomadic access is provided to a portable device,such as a PC card, with expectation of a best-effort handover.

3. Simple mobility: The subscriber may move at speeds up to60 kmph with brief interruptions (less than 1 sec) duringhandoff.

4. Full mobility: Up to 120 kmph mobility and seamlesshandoff (less than 50 ms latency and


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HANDLING MOBILITYINA

WIRELESS ATM NETWORK

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ABSTRACT

The world of wireless telecommunications is rapidly changing. The

capabilities of wirelessnetworks are improving at a steady pace.

This presents a protocol implementation for implementing mobility

in an Asynchronous Transfer Mode (ATM) network.

The vision of the authors is of one "ATM-based wireless

telecommunications network" that is capable of supporting

a variety of today's applications with room to grow foradvanced applications of the future. 1 Introduction Wireless

communication networks.

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e.g cellular telephony, have rapidly grown to be

a sizable part of the world telecommunications

market over the past two decades.

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One reason for the rapid growth of wireless communication networks

(WCN) is the mobility of a tether less terminal. Next generation

wireless networks are called Personal Communication Services (PCS)Networks and will provide for global user mobility, a life-long user

identification numbering system and ability to accommodate varying

data rates.

f handling mobility

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