Trends of Communications Trends of Communications TechnologiesTechnologies

Myung Jong LeeDept. of Electrical Engineering

Cilee@ccny.cuny.edu

KOCSEA Symposium 2009

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Outline

Evolution of Communications Technologies

Recent Entropy Boosters Industry activities: cases in IEEE

802.15

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NBT?Extrapolation

Past historical samples Energy conservation law: 1st law of

thermodynamics Law of entropy: 2nd law of thermodynamics

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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

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Entropy as a measure (2)

In a dictionary• Degree of freedom or degree of randomness or chaos,

degradation In Information Theory:

• 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!

)/1log( iii ppH

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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.

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Entropy DriversDecentralization, distributionFlexibility, future proofPersonalization, user-centricHorizontal market

Blurred distinction between computer and communications

Cross cutting disciplinesEtc, etc.

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Quntum Jumps in Entropy

1. Centralized system to distributed system

2. Circuit Switching to Packet Switching3. Wired to Wireless4. Infrastructure to Infrastructureless5. Toward Ubiquitous Networks Recent Entropy boosters

In Communications

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1. Centralized to distributedSingle large computer: single terminal to

remote multiterminalMultiple mini computersMany personal computersUbiquitous 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 PacketCircuit switching serves well for voice

service for over 100 yearsDedicated services to shared servicesAgain, 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 WirelessPeople 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

InfrastructurelessWireless nodes possibly with

mobilityPossibly 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, directional

antenna• IEEE 802.11ac, ad

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Applications for ad hoc networksEmergency networks

Search-and-rescue, firefighting, policingCivilian environments

Gaming, meeting room, stadium WPAN, WBAN

Cell phone, PDA, earphone, wrist watchVehicle to Vehicle networksMilitaryWireless mesh networksWireless Sensor networksEtc

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5. Ubiquitous Networking

Key capability to maximally

satisfy personalized requirements- user-centric“awareness”

technologyDevice-to-Device

communications

At the center of U Network lies the wireless sensor/control networks

17Courtesy: David Nagel

80’s Microprocessor 90’s InternetThis decade—”Sensors”

Gary Boone of the Accenture Technologies Laboratory asserted that "browsing reality" will prove to be the killer application for wireless sensor networks,

Wireless Sensor Networks

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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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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

Applications

What a home!

Courtesy: Zigbee

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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

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)

Bandwidth and data rate

An Overview of IEEE 802.15.4 (1)

0 1 10. . . . . . 11 26. . . . . .

868 MHz 902 – 928 MHz 2.4 – 2.4835 GHz

20 Kb/s 40 Kb/s 250 Kb/s

2 MHz 5 MHz

868/915 MHz PHY 2.4 GHz PHY

Channel:Frequency:Data rate:

Beacon Mode and Superframe Structure

An Overview of IEEE 802.15.4 (2)

0

Inactive

1 2 3 4 5 6 7 8 9 10 11 12 13

GTS

14 15

GTS

Beacon

CAP CFP

(Active) BI = aBaseSuperframeDuration x 2BO symbols

SD = aBaseSuperframeDuration x 2SO symbols

Beacon

Mesh layer solution based on IEEE 802.15.4-2006

Supporting long battery lifeTwo AA batteries, 1year

Flexible active timeEnd-to-end latency constraintConsidering receiver energy consumption

Tree relation

Easy implementation

Design Consideration

Battery Life

Two AA batteries2000 mA-hr

Energy consumption of cc2420Tx; 17.4 mARx; 19.7 mA

When a device turns on the transceiver4.2 days

When the device keeps 5% active time84 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 problemCan 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 protocolsWith beacon mode

Determining parameters: Beacon interval and superframe duration-Non-beacon Tracking (NBT)-Beacon Tracking (BT)

With non-beacon modeDetermining 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 collisionUpper layer control also required

Synchronous Algorithm with Non-Beacon

SMACTime control precision Difficult to synchronize all devices

LPE

LPEA

Asynchronous with Non-beacon Mode

Average active ratio with the beacon mode

0 0.5 1 1.5 2 2.5 3 3.5 40

1

2

3

4

5

6

7

8

9

10

Wakeup intervals (s)

Act

ive

ratio

(%

)

Anal:NBT

Anal:BTExp:NBT

Exp:BT

Three

Transmitters

and

one receiver

Average active ratios with the non-beacon mode

0 0.5 1 1.5 2 2.5 3 3.5 40

1

2

3

4

5

6

7

8

9

10

Wakeup intervals (s)

Act

ive

ratio

(%

)

Anal:LPEAnal:LPEA

Anal:LPEAS

Anal:GS

Exp:LPE

Exp:LPEAExp:LPEAS

Hop latencies of the algorithms

0 0.5 1 1.5 2 2.5 3 3.5 40

5

10

15

20

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Wakeup intervals (s)

6 ho

p La

tenc

y (s

)

Anal:NBT, BT

Anal:LPEAnal:LPEA, LPEAS

Anal:GS

Exp:BT

Exp:LPEExp:LPEA

Exp:LPEAS

Beacon vs. Non-beacon Mode

Beacon modeSuitable for the networks with

Long beacon interval & small number of neighbors

Hard time beacon transmission beacon collisionUnreliable

NBT; beacon collisionBT; Sync tree problem

Upper layer support forActive time scheduling, minimizing active time, broadcasting frames

Non-beacon modeRequires all operations at the mesh layerDifficulty in timing controlFlexible !, 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

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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

1. Centralized system to distributed system

2. Circuit Switching to Packet Switching3. Wired to Wireless4. Infrastructure to Infrastructureless5. Toward Ubiquitous Networks Recent Entropy boosters

In Communications

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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)

Recent Entropy Boosters

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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 SpectrumFCC 2004 Policy changeNew 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 efficientlyIndustrial Standards Development

IEEE 802.22 (Wireless Regional Area Network: WRAN) IEEE 802.18 (Coexistence) IEEE P1900 ECMA

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16% duty cycle, 30Mhz-3 Ghz, 24Hrs Actually even lower ( <10%)

Spectrum Usage NYC Sept 1, 2004

copyright kiran.challapali@philips.com

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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 802.22-04-0003r0

52Copyright: pkolodzy@stevens-tech.edu

Inerference Avoidance

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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.

IEEE 802.22 WRAN

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IEEE 802.22

from IEEE 802.22-04-0003r0

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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 MIMO (size, power), but cooperation between sensor nodes can achieve a virtual MIMO.

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Basic Relay Model

Source Dest.

Relay

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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IssuesGains 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

own throughput ? Will cooperation improve performance of overall

networks?

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WBANNatural extension

WRAN WMAN WLAN WPAN WBAN Nominal range of 2 m

New regulatory body: FDA in addition to FCCRecently 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, 1395-

1400MHz and 1427-1429.5MHz)– MEDS (medical data service) (401-402MHz and 405-406MHz)– New Band?

• Intrabody

July 2006

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

Courtesy: Stefan Drude, Philips

Body Sensor NetworkMedical application

Vital patient data Wireless sensors Link with bedside monitor Count on 10 – 20 sensors

Five similar networks in rangeMinimum setup interactionPotentially wide applicationTotal traffic / patient < 10 kbps

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Medical and Entertainment

www.newscientists.com

23年 4月 19日

Gastrointestinal Camera

www.givenimaging.com

5

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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 effects) 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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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 !

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Advanced Wireless Research Lab (CUNY)

BasicResearch

Standard

Activities

Testbed &

Prototype

Slide 69 Myung. J. Lee CUNY