DIFFERENCES IN WIRELESS NETWORKS

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DIFFERENCES IN WIRELESS NETWORKS 1.
Channel capacity Limited spectrum
available Power restrictions Noise levels 2.
Noise and interference have more impact on
systems design for wireless systems than on wired
systems 3. Before building a wireless system,
some sort of frequency allocation (by the
Federal Communications Commission in the U.S.) is
required. 4. Security is a greater concern in
wireless systems than in wired systems since the
information may be traveling in free space.
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• WIRELESS AND MOBILE NETWORKS HAVE TO WORRY ABOUT
  -
• Network configuration
  Infrastructure-based
• Ad-hoc configuration
• Limitations of devices
• Content adaptation to device capabilities
• New protocols to handle device limitations
• Bandwidth
• Handoff type of handoff, handoff
  implementation, priority, channel assignment
• Error control

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WIRELESS AND MOBILE NETWORKS HAVE TO WORRY ABOUT
(cont.)- Mobility management Addressing and
routing issues Location Tracking Broadcasting
(paging) to locate a user Location updating by
user after every move Combination of paging and
updating
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• Ad Hoc Wireless Networks
• Mobile nodes interconnected by multihop
  communication paths.
• No fixed network or administrative support.
• Topology varies dynamically as mobile nodes join
  or depart the network or radio links between
  nodes become unusable.
• Self-creating, self-organizing, and
  self-administering
• Ensuring Effective routing is one of the great
  challenges for ad hoc networking.Each node must
  be able to function as routers on demand.

D
A
C
B
5
Evolution Toward Third Generation Wireless
Networks 1-G / 2-G Capable of providing voice
and low-rate data networks Air interfaces
inadequate for satisfying the high data rates
specified by the ITU for IMT-2000. 3-G
requirements High data rates and QoS metrics
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• 1G(analog) - Advanced Mobile Phone System (AMPS)
• Major network deployments in North America, the
  Asia/Pacific region, and Central and Latin
  America with other substantial network operations
  in the Asia/Pacific region.
• 2G systems
• GSM ( Predominant standard in Europe and widely
  deployed throughout the world largest number of
  subscribers)
• IS-136
• IS-95 or cdmaOne
• Digital AMPS (DAMPS)
• Personal Digital Cellular (PDC)
• GSM, IS-136, and PDC TDMA based systems
• IS-95 CDMA

Main standards of North America with other
installations in Central and South America and
Asia/Pacific regions
Only Japan, but second largest digital
subscribers
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• GSM Evolution
• GSM networks will enhance packet data services
  primarily in three phases. General Packet Radio
  Services(GPRS) refers to the first phase of GSM
  network architecture enhancements that allow
  mobiles to connect to IP or X.25 based networks.
• The GSM/GPRS network architecture will further
  evolve to support Enhanced Data Rates for GSM
  Evolution (EDGE), which provides significant
  improvements over GPRS.
• Finally, the ETSI/ARIB Wideband CDMA (WCDMA)
  proposal provides a new air interface for GSM
  networks - supporting higher data rates meets or
  exceeds the UMTS/IMT-2000 specifications.

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• General Packet Radio Services
• Allows GSM mobile subscribers to connect to an
  IP-based or X.25-based network.
• Two new network elements are introduced with GPRS
  to the GSM architecture-
• Serving GPRS support node (SGSN)
• Gateway GPRS support node (GGSN)
• The SGSN provides authentication and mobility
  management.
• GGSN provides the interface between the mobile
  and the IP or X.25 network.

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VLR
PSTN
BTS
MSC
HLR
SGSN
BTS
BSC
IP network
MH
X.25 network
GGSN
BTS
MH-Mobile Host MSC- Mobile switching center
BTS- Base Transceiver station VLR Visitor
location registry BSC-Base Station
controller HLR Home location
registry PSTN Public Switched
Telephone network SGSN- Serving GPRS support
node GGSN Gateway GPRS Support node
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Enhanced Data Rates for GSM Evolution
(EDGE) EDGE reuses the GSM/GPRS time slot
structure 200 kHz carrier and multi-slot
operation allow service providers to deploy EDGE
transceivers among existing GSM/GPRS
transceivers. Adaptive radio link protocol will
be employed to take advantage of the better
channel quality. Note -One of the main
differences between GPRS and EDGE is that EDGE
will use 8-phase shift keying (8-PSK) modulation,
which encodes 3 bits per modulated symbol, as
opposed to the 1-bit per symbol GMSK used in
existing GSM and GPRS networks.
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IS 136 Evolution IS-136, sometimes referred to
as North American TDMA (NA-TDMA), has a two phase
migration path 136 136HS IS-136
significantly improves both the voice and data
services available using the existing 30 kHz
channel bandwidth. Bit rate of 16.2 kbps for a
full-rate channel. Adopting the EDGE standard
(see GSM Evolution) for the outdoor component of
IS-136HS. The main difference between EDGE
deployments in existing IS-136 networks and GSM
networks will be spectrum allocation.
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IS-95 Evolution Also referred to as North
American CDMA (NA-CDMA), has a two phase
migration path IS-95B cdma2000. IS-95
provides circuit-switched and packet-switched
data at rates of 9.6 kbps or 14.4 kbps (depending
on the speech coder) using a 1.25 MHz channel
bandwidth
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GSM -gt GPRS -gt EDGE -gt WCDMA IS-136 networks -gt
136 -gt 136HS(EDGE in outdoor environment) IS-95
(CDMA) -gt IS-95B -gt cdma2000 Currently, numerous
operators have signed contracts with wireless
equipment vendors such as Nokia,Ericsson, Nortel,
and Motorola to provide GPRS data services in
their existing GSM networks. EDGE is to be
deployed in early 2001 WCDMA and cdma2000 are
also undergoing field trials with commercial
deployment possibly slated for the 2002 to 2003
time frame.
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• CURRENT AND EMERGING SYSTEMS/STANDARDS
• Spread Spectrum Frequency Hopping and Direct
  Sequence
• Wireless WANs - Metricom, CDPD , ARDIS
• Wireless proprietary LANs Motorolas Altair,
  ATTs WaveLAN
• LAN Standards IEEE 802.11, HIPERLAN
• Wireless ATM
• Mobile IP

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• QOS AND WIRELESS ACCESS
• QoS is a guarantee by the network to satisfy a
  set of predetermined service performance
  constraints such as
• End-to-end delays
• Available Bandwidth
• Probability of packet loss
• Perceived quality
• Cost
• QoS guarantees can be attained only with
  appropriate resource reservation techniques
• The most important element is QoS routing.
• QoS routing process of choosing the route to be
  used by the flow of packets of a logical
  connection in attaining the associated QoS
  guarantee.

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QoS guarantees are to be kept while topological
changes/updates occur. Exchange of control
packets should be given higher priority than data
packets in a network designed for QoS. Difficulty
in maintaining QoS guarantees when handling
packets of different priorities Also in heavy
traffic situations , guaranteeing QoS for lesser
priority traffic may be extremely difficult. Open
area is the development of QoS routing policies ,
algorithms and protocols for handling user data
with multiple priorities. Similar challenges
exist in developing QoS routing schemes
supporting multiple service classes.
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Security Issues for QoS Routing The routing
protocol should have a robust security policy
such that operation integrity is maintained
against unintended or deliberate attacks. Attacks
can be in the form of Flows making too many
invalid requests Requests for inappropriate
allocation of network resources Attempting to
copy or preempt network control functions.
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• SUMMARY
• QoS Management
• Admission control techniques
• Priority to existing user's resource request
• Dynamic advance reservation
• Adaptive error control techniques
• QOS-oriented MAC protocols
• Channel borrowing from underloaded regions
• Guaranteeing QoS is difficult in wireless
  networks.More so in mobile and multicast
  networks.

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• Mobiware Toolkit QoS aware middleware for Mobile
  Multimedia
• Software Intensive built on CORBA and Java
  distributed object technology
• Based on open programmable paradigm to run on
  mobile devices,wireless access points and
  mobile-capable switch/routers
• Provides a set of open programmable interfaces
  and algorithms for adaptive mobile networking