Transcript WiMAX - Department of Computer Science and Engineering

Advanced Topics in NextGeneration Wireless
Networks
Introduction of Wireless Networks
Qian Zhang
Department of Computer Science
HKUST
Why Wireless?
• Convenience and flexible
• Mobility
• Coverage
anytime
anywhere
• Easy to deploy
• Low cost
any device
• New applications potential
• Improved quality of life (people with
disabilities)
service
4A: Anytime, Anywhere, Any device, and Any service
Fast Growing Devices Create New
Connectivity Demands
Wireless Technologies
coverage
WWAN (3G,4G?)
WMAN (Wi-Max)
WLAN (Wi-Fi)
WPAN
Bluetooth
UWB
RFID
Big Picture – WPAN’s
• 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. MBOAOFDM UWB (Intel+TI)
Ultra WideBand (UWB)
STBs
PVRs
CE
HDTV
Cluster
Mobile
Cluster
VCRs
tablets
camcorders
Console
MP3
audio
cameras
Games
Projector systems
Cordless
Phones
laptops
pocketPC
speakers
storage
devices
printers
PDA
PC
Cluster
Scanners
3G
Handsets
WLAN (WiFi-802.11x)

Physical Layer
Enhancements
802.11a
5 GHz
54 Mbps
1999
802.11b
2.4 GHz
11 Mbps
802.11e
Quality of Service
2001
2003
802.11k
802.11n
Radio Resource
Measurement
100
Mbps (above MAC)
2005
802.11g
802.11i
2.4 GHz Security
Enhanced
54 Mbps
2007
Big Picture –WMAN’s
WiMax (Worldwide Interoperability for Microwave Access)
• Standard & Chipset Availability
2004
2005
2006
2007
2008
Approved 07/04
IEEE 802.16d
Air I/F Fixed BWA
IEEE 802.16e
Air I/F Fixed
& Mobile BWA
Approval 05/05 Corrigenda (TGh)
WiMAX 1st certificate 07/05
Chipset for Indoor-outdoor CPE
Approval 07/05
Approval 05/06 Corrigenda (TGh)
Possible delay
Chipset for PCMCIA No handover
Chipset for Centrino Handset
• Intel is the main driver for WIMAX: Integration in Centrino is the disruptive goal
WiMAX Applications in 2005
IEEE 802.16-2004
WiFi
Mobile PC/PAD
Business, SME, SOHO Access
WiMAX
Base Station
Fixed Services
Nomadic PC
Residential Fixed
WDSL BB Access
NB or
BTS
WiFi-Hotspot
Feeding
2G/3G Feeding
Airport
Campus
Hot Zones
WiMAX Applications in 2006-2007
WiFi
Mobile PC/PAD
Business, SME, SOHO Access
Nomadicity, Solutions
for Laptops (PCMCIA)
WiMAX
Base Station
IEEE 802.16-2004
& IEEE 802.16e
Nomadic PC
Residential Fixed
WDSL BB Access
NB or
BTS
WiFi-Hotspot
Feeding
2G/3G Feeding
Airport
Campus
Hot Zones
WiMAX Applications in 2007-2008
IEEE 802.16e
WiFi
Mobile PC/PAD
WiMAX
Business, SME, SOHO Access
Base Station
Fully Mobile,
Integrated Solutions
in Laptops and PAD
Portable PC
Residential Fixed
WDSL BB Access
NB or
BTS
WiFi-Hotspot
Feeding
2G/3G Feeding
Airport
Campus
Hot Zones
WWAN (3G and Beyond)
WMAN (802.16e)
TD-SCDMA
OFDM-5MHz (2-6GHz)
15Mbps (60kmph)
5MHz
2Mbps
Services/Applications
WLAN (802.11)
20MHz
54Mbps
Harmonized
All IP CN
HSDPA
UWB (802.15.3a)
7.5GHz (3.1-10.6GHz)
480+Mbps
IP Network
5MHz
10Mbps
Services/Applications
MBWA (802.20)
OFDM-5MHz (<3.5GHz)
5Mbps (250kmph)
CDMA2000
1xEV-DV
1.25MHz
5Mbps
WCDMA
5MHz
2Mbps
Overlay Networks
- the Global Goal
Integration of heterogeneous fixed and
mobile networks with varying
transmission characteristics
vertical
hand-over
regional
metropolitan area
campus-based
horizontal
hand-over
in-house
Wireless Networks vs.
Fixed Networks
• Restrictive regulations of frequencies
– Frequencies have to be coordinated, useful frequencies
are almost all occupied
• Low transmission rates
– Local 11~54 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
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
Influence of Wireless Communication
to the Layered Model
• Application layer
• Transport layer
• Network layer
• Data link layer
• Physical layer
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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
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
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
Ad Hoc Network Characteristics
•
•
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Peer-to-peer
Multihop
Dynamic
Low power
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•
•
•
Zero-administration
Auto-configured
Autonomous
Really “anytime, anywhere”
Wireless Mesh Networks
Most the relay nodes are assumed to be static
Key Players:
Motorola
Nortel
Microsoft
Intel (802.11s)
Meshdynamics
Firetide
Strix
Bellair
….
Possible Applications for Multi-Hop
Networks
• Emergency response
• Military communications
• Broadband Internet access sharing
• WLAN coverage extension
• Home and conference networks
• Community networks
The Spectrum Problem
All Spectrum May Be Assigned, But … Most Spectrum is Unused
Spectrum Dilemma: We are not running out of
spectrum; we simply aren’t using it properly!
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
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
Trends – Industry
• Two distinct markets evolve with different
technologies and paradigms
Wide area wireless
•
•
•
•
Seamless mobility
High speeds
Any-time anywhere
Moderate data rates
Local access wireless
• ”Cordless” access
• Stationary use
• High data rates
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”
Wide Area Ambient Networks
Office
Public GPRS
Networks
Public UMTS
Networks
Home
WLAN
WPAN (BT)
WLAN & UWB
WMAN (WiMAX)
End-to-end Reconfigurability for
Seamless Experience
Heterogeneous Environments and Contexts
Heterogeneous Systems
Fixed
Ubiquitous Access
WLAN
Pervasive Service
Dynamic
Resource Management
Other
Access
Networks
WiMAX
Different administrative
domains
All-IP
infrastructure
2.5/3G
4G
DAB
DVB
UWB
Heterogeneous Devices
Move Forward: Cognitive
Networking and System
Sense/Aware
Autonomy
Automatic
Environment
Understanding
and Dynamic
Spectrum Utilization
Mistake Correcting
Adapt
Learning