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Advanced Topics in Next-Generation Wireless Networks

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Advanced Topics in Next-Generation Wireless Networks Introduction of Wireless Networks Qian Zhang Department of Computer Science HKUST – PowerPoint PPT presentation

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Title: Advanced Topics in Next-Generation Wireless Networks


1
Advanced Topics in Next-Generation Wireless
Networks
Introduction of Wireless Networks
  • Qian Zhang
  • Department of Computer Science
  • HKUST

2
Why Wireless?
  • Convenience and flexible
  • Mobility
  • Coverage
  • Easy to deploy
  • Low cost
  • New applications potential
  • Improved quality of life (people with
    disabilities)

anytime
anywhere
any device
service
4A Anytime, Anywhere, Any device, and Any service
3
Fast Growing Devices Create New Connectivity
Demands
4
Wireless Technologies
coverage
Bluetooth UWB RFID
WWAN (3G,4G?)
WMAN (Wi-Max)
WLAN (Wi-Fi)
WPAN
5
Big Picture WPANs
  • WPAN technologies RFID, Bluetooth, UWB
  • RFID used in tagging applications, restricted
    environments (supermarkets, institutions)
  • 10 billion RFID tags been sold by the end of 2005
    (source Deloitte Touche)
  • Bluetooth technology has matured
  • 56 of mainstream devices commercialised will
    have Bluetooth support by 2008 (Source IDC)
  • UWB bandwidth larger than 500MHz
  • Two main camp DS-UWB (Motolora) vs. MBOA-OFDM
    UWB (IntelTI)

6
Ultra WideBand (UWB)
PVRs
STBs
Mobile
CE
Cluster
HDTV
Cluster
Cordless
Phones
VCRs
tablets
laptops
3G
camcorders
Console
Handsets
MP3
cameras
audio
Games
pocketPC
systems
Projector
PDA
speakers
PC
storage
devices
Cluster
printers
Scanners
7
WLAN (WiFi-802.11x)
  • Physical Layer
  • Enhancements

802.11k Radio Resource Measurement
802.11a
802.11e Quality of Service
802.11n
5 GHz
100 Mbps (above MAC)
54 Mbps
802.11b
802.11g
802.11i Enhanced Security
2.4 GHz
2.4 GHz
11 Mbps
54 Mbps
8
Big Picture WMANs
WiMax (Worldwide Interoperability for Microwave
Access)
  • Standard Chipset Availability
  • Intel is the main driver for WIMAX Integration
    in Centrino is the disruptive goal

9
WiMAX Applications in 2005
IEEE 802.16-2004
WiMAX Base Station
Mobile PC/PAD
Business, SME, SOHO Access
Fixed Services
Nomadic PC
Residential Fixed WDSL BB Access
Campus
Hot Zones
10
WiMAX Applications in 2006-2007
WiMAX Base Station
Mobile PC/PAD
Nomadicity, Solutions for Laptops (PCMCIA)
Business, SME, SOHO Access
IEEE 802.16-2004 IEEE 802.16e
Nomadic PC
Residential Fixed WDSL BB Access
Campus
Hot Zones
11
WiMAX Applications in 2007-2008
IEEE 802.16e
WiMAX Base Station
Mobile PC/PAD
Business, SME, SOHO Access
Fully Mobile, Integrated Solutions in Laptops
and PAD
Portable PC
Residential Fixed WDSL BB Access
Campus
Hot Zones
12
WWAN (3G and Beyond)
WMAN (802.16e) OFDM-5MHz (2-6GHz) 15Mbps (60kmph)
TD-SCDMA 5MHz 2Mbps
Services/Applications
WLAN (802.11) 20MHz 54Mbps
Harmonized All IP CN
UWB (802.15.3a) 7.5GHz (3.1-10.6GHz) 480Mbps
HSDPA 5MHz 10Mbps
IP Network
Services/Applications
MBWA (802.20) OFDM-5MHz (lt3.5GHz) 5Mbps (250kmph)
CDMA2000 1xEV-DV 1.25MHz 5Mbps
WCDMA 5MHz 2Mbps
13
Overlay Networks - the Global Goal
Integration of heterogeneous fixed and mobile
networks with varying transmission characteristics
vertical hand-over
horizontal hand-over
14
Wireless Networks vs. Fixed
Networks
  • Restrictive regulations of frequencies
  • Frequencies have to be coordinated, useful
    frequencies are almost all occupied
  • Low transmission rates
  • Local 1154 Mbit/s, regional currently, e.g., 40
    kbit/s with GPRS/CDMA
  • Higher loss-rates due to interference
  • Emissions of, e.g., engines, lightning
  • Higher delays, higher jitter
  • Connection setup time with several hundred
    milliseconds for some wireless systems

15
Wireless Networks vs. Fixed Networks
(Cont.)
  • Lower security, simpler active attacking
  • Radio interface accessible for everyone, base
    station can be simulated, thus attracting calls
    from mobile phones
  • Always shared medium
  • Secure access mechanisms important
  • Close and complex inter-layer interaction

16
Influence of Wireless Communication to the
Layered Model
OSI or TCP /IP stack MAY NOT be the way to
go! Current Trend Eliminate layers or
introduce hooks such that layers can interact
with each other
  • service location
  • new applications, multimedia
  • adaptive applications
  • congestion and flow control
  • quality of service
  • addressing, routing, device location
  • hand-over
  • authentication
  • media access
  • multiplexing
  • media access control
  • encryption
  • frequency
  • modulation
  • interference
  • attenuation
  • Application layer
  • Transport layer
  • Network layer
  • Data link layer
  • Physical layer

17
Classification of Wireless Networks
  • Cellular Networks
  • Organized, base stations that are regularly
    placed. Mobiles communicate only with base
    stations
  • Wireless LANs
  • Less organized access points with which mobile
    nodes communicate
  • Ad hoc/Multi-hop networks
  • No infrastructure nodes potentially move and
    network dynamically changes
  • Sensor Networks
  • application specific mobility is limited
    (perhaps to selected subset of nodes) tiny nodes
    that are resource and energy constrained

18
Ad Hoc Network Characteristics
  • Peer-to-peer
  • Multihop
  • Dynamic
  • Low power
  • Zero-administration
  • Auto-configured
  • Autonomous
  • Really anytime, anywhere

19
Wireless Mesh Networks
Most the relay nodes are assumed to be static
Key Players Motorola Nortel Microsoft Intel
(802.11s) Meshdynamics Firetide Strix Bellair .
20
Possible Applications for Multi-Hop Networks
  • Emergency response
  • Military communications
  • Broadband Internet access sharing
  • WLAN coverage extension
  • Home and conference networks
  • Community networks

21
The Spectrum Problem
All Spectrum May Be Assigned, But Most
Spectrum is Unused
Spectrum Dilemma We are not running out of
spectrum we simply arent using it properly!
22
Overview of Open Spectrum
Open spectrum enables opportunistic spectrum
access to provide 10x Improvement by reusing
wasted spectrum
  • Primary devices
  • Utilize assigned spectrum when desired
  • Movement and channel utilization varies over time
  • Secondary devices
  • Seek to utilize remaining available channels
    without interfering primary users
  • Find optimal balance between maximizing spectrum
    utilization and minimizing harmful interference

Requirement cognitive radios
channels
23
What is a Cognitive Radio?
  • Wireless communication radios e.g., 802.11
    a/b/g/n, can be described as fixed and adaptive
  • A fixed radio has its technical characteristics
    set at the time of manufacturing
  • An adaptive radio can respond to channel
    conditions that represent one of a finite set of
    anticipated events
  • Cognitive radios
  • It can dynamically take advantage of spectrum
  • It provides spectral awareness in support of FCC
    initiatives in spectral reuse
  • Can respond intelligently to an unanticipated
    event, i.e., a channel that it has never
    encountered before
  • It can take decisions based on many trained
    observations

24
Trends Industry
  • Two distinct markets evolve with different
    technologies and paradigms

Local access wireless
Wide area wireless
  • Cordless access
  • Stationary use
  • High data rates
  • Seamless mobility
  • High speeds
  • Any-time anywhere
  • Moderate data rates

25
Trends Technology
  • Increasingly complex and heterogeneous network
    environment
  • Many different types of networks, from simple to
    complex, operated by different types of operators
  • Many different access technologies - but several
    of those developed today will not survive
  • More niche wireless standards no single 4G
    radio standard
  • Gradually shift towards multi-standard Ambient
    Networks

26
Wide Area Ambient Networks
Office
Public GPRS Networks
Public UMTS Networks
WLAN
WPAN (BT)
Home
WLAN UWB
WMAN (WiMAX)
27
End-to-end Reconfigurability for Seamless
Experience
Heterogeneous Environments and Contexts
Heterogeneous Devices
28
Move Forward Cognitive Networking and System
Sense/Aware
Automatic Environment Understanding and
Dynamic Spectrum Utilization
Autonomy
Adapt
Learning
Mistake Correcting
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