Transcript Simple AODV
KOCSEA Symposium 2009
Trends of Communications
Technologies
Myung Jong Lee
Dept. of Electrical Engineering
[email protected]
Outline
Evolution of Communications Technologies
Recent Entropy Boosters
Industry activities: cases in IEEE 802.15
2
NBT?
Extrapolation
Past historical samples
Energy conservation law: 1st law of
thermodynamics
Law of entropy: 2nd law of thermodynamics
3
Entropy as a measure (1)
Entropy
In thermodynamics:
• Definition: S=q/T (joules/degree)
– Tendency of spontaneous energy becoming
diffused and spread out
• Natural progress or phenomena in the
direction of increased entropy
– Wind blows, ice melts, mountain lowers and
valley rises,
– Berlin wall torn down, equal rights for women,
etc
4
Entropy as a measure (2)
In a dictionary
• Degree of freedom or degree of randomness or chaos,
degradation
In Information Theory:
H pi log(1 / pi )
i
• Pi: the probability of event I
• Maximum Entropy when Pi ‘s are equal. Uniform
distribution
– (socio-political views) elite group (monarchy)
democracy (all people)
– Possession of information: “知彼知己 百戰百勝”
• Internet, ubiquitous networks: information age!
5
Entropy as a measure (3)
In short, Leveling Force is the core of the entropy
law!
Democratization, equal right’s movement, empowering
individuals, fostering egalitarian society even for animal,
plants, and environment (utopia?) etc.
6
Entropy Drivers
Decentralization, distribution
Flexibility, future proof
Personalization, user-centric
Horizontal market
Blurred distinction between computer and
communications
Cross cutting disciplines
Etc, etc.
7
Quntum Jumps in Entropy
In Communications
1.
2.
3.
4.
5.
Centralized system to distributed system
Circuit Switching to Packet Switching
Wired to Wireless
Infrastructure to Infrastructureless
Toward Ubiquitous Networks
Recent Entropy boosters
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1. Centralized to distributed
Single large computer: single terminal to remote
multiterminal
Multiple mini computers
Many personal computers
Ubiquitous computing or networking
• Provide computing resources wherever demands exist.
• Grid computing, nano computing, biocomputing, etc
This evolution demands efficient communication
and management
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2. Circuit to Packet
Circuit switching serves well for voice service for
over 100 years
Dedicated services to shared services
Again, demands for flexibility, multimedia (voice,
video, data), personalization lead to packet
switching Packet switched Internet -> VOIP
No technology without problems!
Problems are mainly due to increased degree of
randomness
Diverse QoS’s for multimedia, Congestion, etc
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3. Wired to Wireless
People as well as machine long to be untethered
Evolution of wireless communications
1st generation: analog
• AMPS
2nd generation: digital (voice+data)
• IS-95, GSM, CDPD for data
3rd generation: digital (voice+data+low rate
video)
• IMT-2000 (3GPP, 3GPP2), Cdma 2000, GSM (wider
bandwidth)
• WBMA (IEEE 802.16, 20), WLAN (IEEE802.11), WPAN (IEEE
802.15, ZigBee), WBAN (IEEE 802.15 IG)
4th generation: Network convergence
• multimedia (HDTV), IMT-Advanced (ITU-R)
• Unifying PHY, MAC with SDR?
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4. Infrastructure to infrastructureless
Wireless Communication infrastructure
Base station or Access point based
•
•
•
•
•
WWAN “last mile” wireless
WLAN (WiFi) “last 100m” wireless
WPAN “last 10m” wireless
WBAN “last 2m” wireless
Or, Macrocell, Microcell, Nanocell, Femtocell
Infrastructureless or Wireless Ad hoc networks
Peer-to-peer mesh communications without BS or AP
• No “last x” wireless
• Mobile Ad hoc networks (MANET), Wireless Mesh networks,
WSN, WBAN
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Ad Hoc Networks
Infrastructureless
Wireless nodes possibly with mobility
Possibly multiple hops between network
nodes
Router or relay node as well as end-node
Multihop occurs as data rate gets higher.
• IEEE 802.11b (100m)802.11a (<<100m)
• IEEE 802.15.3c (mmwave) Multihp,
antenna
• IEEE 802.11ac, ad
directional
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Applications for ad hoc networks
Emergency networks
Search-and-rescue, firefighting, policing
Civilian environments
Gaming, meeting room, stadium
WPAN, WBAN
Cell phone, PDA, earphone, wrist watch
Vehicle to Vehicle networks
Military
Wireless mesh networks
Wireless Sensor networks
Etc
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5. Ubiquitous Networking
Key capability to
maximally
satisfy personalized
requirements-
user-centric
“awareness” technology
Device-to-Device
communications
At the center of U
Network lies the wireless
sensor/control networks
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Wireless Sensor Networks
80’s Microprocessor
90’s Internet
This decade—”Sensors”
Gary Boone of the Accenture Technologies
Laboratory asserted that "browsing reality" will
prove to be the killer application for wireless
sensor networks,
Courtesy: David Nagel
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Wireless Sensor Networks
Multihop ad hoc networks, but relatively
static
Resource constraints: energy, processing,
memory
Potentially numerous (inexpensive)
Wireless channels: intermittent and
bandwidth-limited
Miniaturization
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WIRELESS SENSOR NETWORKS
Courtesy: David Nagel
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Applications
Automation and control:
home
Factory, warehouse
Energy saving (NYC apartment complex project)
Monitoring
Safety, security
Health (BAN)
Environments (agriculture, building, aqueous, etc)
Situational awareness and precision asset location (PAL)
military actions
Ssearch and rescue (breadcrumb comm, use of mice?)
autonomous manifesting
Inventory tracking
Entertainment
learning games
interactive toys
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What a home!
Courtesy: Zigbee
Some Research Issues
Key is to integrate communication, processing, and
sensors in a miniaturized platform to provide
ubiquitous sensing and control environment.
General
Energy, Energy harvesting
Crosslayer Optimization (QoS, scalability, reliability,
efficiency)
Self Organization, Self healing
Connection to widearea networks: Gateway (conversion
or convergence)—IEEE 802.15.5, IETF 6lowpan, ROLL
Security
data fusion, mining
Miniaturization (antenna, etc)
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Research Issues (2)
At Protocol Layers
PHY (adaptive modulation, voltage scaling, antenna, CR)
Energy Efficient MAC (synchronous, asynchronous,
asymmetry approach, wakeup radio, multichannel/CR
MAC, Virtual MIMO, cooperation)
Link control (hybrid of ARQ/FEC, power control)
Network (addressing, routing (unicast, multicast,
broadcast, geocast), beacon scheduling, topology
control, frequency agility, CR, cooperation, network
coding)
Transport (wireless multihop)
Applications (data fusion, unifying data format IEEE1451)
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Energy Saving Example
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Energy Saving for WSN
For IEEE 802.15.5 WPAN Mesh
Power saving algorithms are needed for IEEE
802.15.5 WPAN Mesh for wireless
sensor/control networks
Using IEEE 802.15.4 device
One of the advantage of using IEEE 802.15.5
mesh for WSN (sleeping router)
An Overview of IEEE 802.15.4 (1)
Bandwidth and data rate
868/915 MHz PHY
2 MHz
Channel:
0
Frequency: 868 MHz
Data rate:
20 Kb/s
1
2.4 GHz PHY
5 MHz
......
10
902 – 928 MHz
40 Kb/s
11
......
2.4 – 2.4835 GHz
250 Kb/s
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An Overview of IEEE 802.15.4 (2)
Beacon Mode and Superframe Structure
Beacon
Beacon
GTS
GTS
Inactive
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CAP
CFP
SD = aBaseSuperframeDuration x 2SO symbols
(Active)
BI = aBaseSuperframeDuration x 2BO symbols
Design Consideration
Mesh layer solution based on IEEE 802.15.4-2006
Supporting long battery life
Two AA batteries, 1year
Flexible active time
End-to-end latency constraint
Considering receiver energy consumption
Tree relation
Easy implementation
Battery Life
Two AA batteries
2000 mA-hr
Energy consumption of cc2420
Tx; 17.4 mA
Rx; 19.7 mA
When a device turns on the transceiver
4.2 days
When the device keeps 5% active time
84 days (under 3 months)
Minimizing active ratio is the key!
Mesh Layer Solution
Why Algorithms at Mesh Layer?
MAC access limited in many transceivers,
-MAC information not accessible
-Cannot add MAC control frames
-Only access via standard primitives
At mesh layer,
flexible and platform independent
Timing problem
Can not guarantee response time
Ex. The time from calling MCPS-DATA.request to starting backoff
Representative Algorithms
6 Generic Power Saving Algorithms
applicable to a wide range of MAC
protocols
With beacon mode
Determining parameters: Beacon interval and superframe
duration
-Non-beacon Tracking (NBT)
-Beacon Tracking (BT)
With non-beacon mode
Determining parameters: Wakeup interval and wakeup
duration
-Long Preamble Emulation (LPE); BMAC
-Long Preamble Emulation with Ack (LPEA); XMAC
-Non-beacon Tracking Emulation (NTE)
-Global Synchronization (GS); SMAC
Algorithms with Beacon Mode
Reliability, Beacon collision
Upper layer control also required
Synchronous Algorithm with Non-Beacon
SMAC
Time control precision
Difficult to synchronize all devices
Asynchronous with Non-beacon Mode
LPE
LPEA
Average active ratio with the beacon mode
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Anal:NBT
Anal:BT
Exp:NBT
Exp:BT
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8
Active ratio (%)
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Three
Transmitters
6
5
and
one receiver
4
3
2
1
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Average active ratios with the non-beacon mode
10
Anal:LPE
Anal:LPEA
Anal:LPEAS
Anal:GS
Exp:LPE
Exp:LPEA
Exp:LPEAS
9
8
Active ratio (%)
7
6
5
4
3
2
1
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Hop latencies of the algorithms
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Anal:NBT, BT
Anal:LPE
Anal:LPEA, LPEAS
Anal:GS
Exp:BT
Exp:LPE
Exp:LPEA
Exp:LPEAS
6 hop Latency (s)
20
15
10
5
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Beacon vs. Non-beacon Mode
Beacon mode
Suitable for the networks with
Long beacon interval & small number of neighbors
Hard time beacon transmission beacon collision
Unreliable
NBT; beacon collision
BT; Sync tree problem
Upper layer support for
Active time scheduling, minimizing active time, broadcasting frames
Non-beacon mode
Requires all operations at the mesh layer
Difficulty in timing control
Flexible !, can make better solutions for large scale
networks
For Large WSN Environment with LPEA
The Key to control the energy consumption is the
wakeup interval
Global Optimization with Unicast and broadcast
Minimize Energy consumption vs Maximizing Network life
time with wake-up interval
Homogeneous WI
Non-homogeneous WI
Heuristics
For Network Environment with LPEA
50 Node
Network
For Network Environment with LPEA
Optimization Problem for unicast
Minimize energy
consumption
Maximize Network
Lifetime
Active Ratio
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Performance Comparison
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Performance Comparison
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Quntum Jumps in Entropy
In Communications
1.
2.
3.
4.
5.
Centralized system to distributed system
Circuit Switching to Packet Switching
Wired to Wireless
Infrastructure to Infrastructureless
Toward Ubiquitous Networks
Recent Entropy boosters
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Recent Entropy Boosters
Dynamic Spectrum Technology-leveling disparity in
spectrum use
Leveling disparity
Cognitive Radio
MIMO
Leveling the spatial & frequency disparity
• Array gain, SNR gain, enhanced data rate, etc
Cooperative Communications (virtual MIMO)
Leveling spatial and frequency disparity
WBAN
Personalization, decentralization, leveling spatial and
frequency disparity
FiWi
lowering the wall between Fiber and Wireless
Ex: RoF (Radio over Fiber)
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Bandwidth—name of the game
Avenues
Bandwidth and power efficiency (Bits/Hz/Joule)-64QAM and Turbo coding get near Shannon limit. –fill
the hole in bandwidth
Dynamic spectrum; spectrum sharing…fill the gap
New spectrum: very costly, therefore, exploring tera
hertz band (electronics limitation) –IEEE 802.15
Interest group for THz. –dispersion to unexplored
territory
Spatial reuse: cellular concept. (lowering transmit
power –boosting channel/hz
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Dynamic Spectrum
FCC 2004 Policy change
New spectrum policy to mitigate the scarcity of
spectrum resource
Unlicensed operation for TV bands (white space)
Ch. 5-13, Ch.21-51 (except ch.37) (76-698 Mhz)
Ch. 14-21 in rural area
Opportunistic Spectrum Sharing : Space and Time
Primary (vertical) sharing—finding and using white space
Secondary (horizontal) sharing –dissimilar networks then
sharing spectrum efficiently
Industrial Standards Development
IEEE 802.22 (Wireless Regional Area Network: WRAN)
IEEE 802.18 (Coexistence)
IEEE P1900
ECMA
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Spectrum Usage NYC Sept 1, 2004
16% duty cycle, 30Mhz-3 Ghz, 24Hrs
Actually even lower ( <10%)
copyright [email protected]
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Cognitive Radio
To protect licensed service operator
Essential component of SDR
To aware of spectrum usage in vicinity
Time and space
Cooperative sensing, etc
Intelligent decision on sensing results.
Current research focus:
Fast and accurate spectrum sensing (energy & feature)
Spectrum management
Radio technologies
from IEEE 802.22-040003r0
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Inerference Avoidance
Copyright: [email protected]
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IEEE 802.22 WRAN
Scope
To specify the air interface (PHY and MAC)
Fixed point-to-multipoint wireless regional area networks
operating in the VHF/UHF TV broadcast bands between
500MHz and 862 MHz.
Purpose
Alternatives to wireline broadband access to diverse
geographic areas (rural areas, etc),
Use of TV bands.
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IEEE 802.22
from IEEE 802.22-040003r0
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Cooperative communication
Node close together can cooperate each other:
cooperatively receive, form a multiple-antenna receiver
cooperatively transmit, form a multiple-antenna transmitter
Virtual MIMO
It may not be practical for sensor networks to adopt the real MI
MO (size, power), but cooperation between sensor nodes can
achieve a virtual MIMO.
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Basic Relay Model
Relay
Source
Dest.
Two general approaches for Relay
Decode-Forward
Amplify-Forward
Relay scenario:
Rayleigh fading channels + AWGN noise
Half-Duplex constraint
Channel State Information (CSI)
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Issues
Gains vs. Overhead
How much gains from cooperation?
Will the gain outweigh overhead incurred by it?
Cooperative partner selection, CSI information sharing
Cooperative coding design (space-time coding)
Power control
Real network environment
Will cooperation cause more collisions in real large
networks?
How often will cooperation happen in a practical network?
Performance gain at the relay node at the price of its ow
n throughput ?
Will cooperation improve performance of overall network
s?
57
WBAN
Natural extension
WRAN WMAN WLAN WPAN WBAN
Nominal range of 2 m
New regulatory body: FDA in addition to FCC
Recently Standard activity IEEE 802.15.6
Wearable and Implanted
Single PHY or Multiple PHY
Frequency BANDs
• ISM Band: 868/915MHz, 2.4GHz, 5.8GHz
• UWB band: 150-650MHz, Low band (3.24-4.74GHz), High band
(5.94-10.23GHz)
• Medical bands
– MICS (medical implant communication service) (402-405MHz)
– WMTS (wireless medical telemetry service) (608-614 MHz, 13951400MHz and 1427-1429.5MHz)
– MEDS (medical data service) (401-402MHz and 405-406MHz)
– New Band?
• Intrabody
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Body Area Networks
Usage Scenarios
Body senor network
Fitness monitoring
Wearable audio/video
Mobile device centric
Remote control &
I/O devices
Courtesy: Stefan Drude, Philips
July
2006
Body Sensor Network
Medical application
Vital patient data
Wireless sensors
Link with bedside monitor
Count on 10 – 20 sensors
Five similar networks in range
Minimum setup interaction
Potentially wide application
Total traffic / patient < 10 kbps
Courtesy: Stefan Drude, Philips
July
2006
Medical and Entertainment
www.newscientists.com
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Gastrointestinal Camera
www.givenimaging.com
5
201507-18
IEEE 802.15.6 Technical Issues
Operates on, inside, or in the vicinity of the body.
Limited range (< .01 – 2 meters)
The channel model will include human body effects. (absorption, health ef
fects)
Extremely low consumption power (.1 to 1 mW) for each device
Capable of energy scavenging / battery-less operation
Support scalable Data Rate: 0.01 – 1,000 kbps (opt 10Mbps)
Support different classes of QoS for high reliability, asymmetric traffic,
power constrained.
Needs optimized, low complexity MAC and Networking layer
High number of simultaneously operating piconets required.
Application specific, security/privacy required.
Small form factor for the whole radio, antenna, power supply system
Locating radios (” find me”) mode.
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64
IEEE 802.15 (WPAN)
Wireless Personal Area Networks (WPAN) with nominal range of
10-30m
Branched from IEEE 802.11 WG 10 years ago
Completed:
802.15.1: Bluetooth v.1.0: 1Mbps
802.15.2: Coexistence between 802.11
802.15.3a: Very high rate UWB PHY for commercial applications
(disbanded)
802.15.3b: MAC for high rate applications
802.15.3c: PHY 500Mbps for commercial applications at 60GHz
802.15.4, 4b: low power, low rate (256Kbps)--lower two layers for
ZigBee
802.15.4a: UWB for ranging and midrate upto 25 Mbps
802.15.5: WPAN Mesh based on 15.4b—2.5 layer approach
802.15.c, 15.d: 15.4 PHY for China and Japan
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IEEE 802.15 (WPAN)
On going
802.15.4e: MAC enhancement for inudustrial applications
802.15.4g: SUN for smart grid
802.15.6: WBAN
802.15.7: Visual Light Communications
802.15.4f: RFID
Interest Group: Terahertz group
More details at IEEE 802.15 WG home page!
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In summary,
Entropy Law may be able to explain and predict,
in perspective, the IT technology trend !
67
Advanced Wireless Research Lab (CUNY)
Standard
Activities
Basic
Research
Testbed &
Prototype
68
Slide 69
Myung. J. Lee CUNY