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HANDLINGMOBILITYHANDLING MOBILITY
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GMOBILITY
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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GMOBILITY
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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GMOBILITY
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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GMOBILITY
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.
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