siscom chair inaugural lecture - imt...

SISCOM Chair Inaugural Lecture

Prof. Trevor HALL

10/11/2010

Optics Departmentpage 1

Can photonic network technology

bring broadband access to all and

help save the planet?

Outline

1. GHG Emissions & ICT

2. Energy consumption of ICT

3. Green Fixed Networks

4. Green Mobile Networks

5. Green Photonics

6. Conclusions

Optics Department

Climate Change

page 2 Source : IPCC Fourth Assessment Report, Climate Cha nge 2007

► 15-30% cut in GHG emissions

needed by 2020 to keep

temperature increase under 2°C

►60-80% reduction may

be needed by 2050

We have a problem !

Optics Department

World Energy Today

page 3

Electricity = 30% Primary Energy

CO2 emissions:

1W Electricity = 2.1 W Primary Energy

Source: Mario Pickavet, IBBT – Ghent University ECOC 2008 SymposiumNetwork Solutions to Reduce the Energy Footprint of ICT

Optics Department

ICT Supply Chain

page 4

Electrical Power Sources

Data & Network Centres

Service & Application Providers

Enterprises & Users

Optics Department

Can ICT save the planet?

Virtualisation & Dematerialisation

� SMART 2020 identified savings of 7.8 Gt CO2e that could be delivered by ICT solutions in 2020 : 5X the sector’s footprint, 15% of global emissions

page 5

Source: European Commission Joint Research Centre, “The Future Impact of ICTs on Environmental Sustainability”, August 2004

http://www.smart2020.org/

Optics Department

ICT Emissions

� ICT industry emissions of 830m tons CO2

in 2007 accounted for 2% of global

emissions and is comparable to the

aviation industry.

� ICT is 5th largest industry in terms of

electrical power consumption

• Telecom Italia is the second largest

consumer of electrical power in Italy

after the railway system

� ICT emissions growth is faster than any

other industry sector doubling every 4

years.

Source: An Inefficient Truth, 2007, Global Action Plan

http://www.globalactionplan.org.uk/green-it

page 6

Optics Department

Home networks

page 7Source : Deutsche Telekom

An extreme example of broadband multimedia home networks

Optics Department

Cautions

� Whole Lifecycle Emissions

• GHG emissions from manufacturing & disposal phases of ICT hardware comparable to the use phase

• Reduced “churn” necessary

� Rematerialisation

• Whatever happened to “the paperless office”?

• Paper consumption has increased with the introduction of ICT

� Jevon’s Paradox

page 8

Optics Department

Jevon’s Paradox

� Khazzoom-Brookes postulate: Increased

energy efficiency paradoxically tends to lead

to increased energy consumption.

page 9

Increased energy efficiency by itself is not enough.

Sustainability requires other forms of governmental/legal

intervention.

Source: http://en.wikipedia.org/wiki/Jevons_paradox

Optics Department

France Telecom Network Energy Consumption

page 10

Source : Laetitia Souchon Foll, PhD, Telecom & Management SudParis, 2008

Optics Department

Why does it take so much energy

to move mass-less information?

page 11

“This energy argument suggests that all except the shortest intrachip communications should be optical”

D A B Miller, ‘ Optics for low-energy communication within digital processors: quantum detectors, sources, and modulators as efficient impedance convertors’, Opt. Lett., 14(2), 1989, 146-148.

Optics Department

Retaining Data in the Optical Domain

� Transporting data in the optical domain

• Optical Networks- Replacing copper legacy networks (mainly access) by optical, i.e.

deploying FTTx (e.g. Fibre to the Home : FTTH)

• Optical Interconnections ?- O/E/O conversions are expensive

� Minimising O/E/O conversions

• A “green” optoelectronics challenge : making O/E/O conversions more efficient - Energy consumption of optoelectronic interfaces many orders of

magnitude greater than estimates of fundamental limits

page 12

Optics Department

Data Centres

page 13

Source: C. Randy Giles, ‘GreenTouch: Meeting the Challenge of Energy Usage in the ICT industry’, IWFIPT, Kyoto, 2010

Optics Department

A computer scientist’s dream

� Purchasing green power locally is expensive with high transmission line losses

• Demand for green power within cities expected to grow dramatically

� Data centers

• Cooling is also a major problem in cities

� Most renewable energy sites are very remote and impractical to connect to

electrical grid.

• But can be easily reached by an optical network

• May also meet some of government’s objectives of extending broadband to

rural/remote areas

Data Centres do not need to be located in cities

� Eliminate enterprise servers and move existing business and consumer

applications to clouds and virtual servers at zero carbon data centres

� Eliminate consumer PC and use hand held devices or solar powered devices to

access applications over Internet

• RIM Blackberry or Apple iPhone

page 14


“Zero Carbon” data centers connected by optical networks


Virtual Relocation : Follow the Sun / Wind

� Opportunistically relocate infrastructure without interrupting user services

� Data is relocated

� Network is automatically

reconfigured to direct traffic

to the new data centre

� Servers and end users keep

the same IP addresses

Virtual Network & Compute

Infrastructure


But what is in the cloud?

http://www.caida.org/home/

Optics Department

Packet Switched Networks

page 18

A

B

C

R1

R2

R3

R4 D

E

FR5

Source: Nick McKeown http://yuba.stanford.edu/~nickm/


Router Power Consumption

0

2

4

6

8

10

12

14

16

1990 1993 1996 1999 2002 2003 2004

Pow

er (

kW)

Power Consumption per chassisSource: Nick McKeown 2006

Cisco CRS-1 Router

92 Tbps on 80 Racks

Energy consumption :

Powering ~ 1 MW

Air-conditioning ~ 1MW


Utilisation: capacity dimensioned for peak load

Source : Laetitia Souchon Foll, PhD, Telecom & Management SudParis, 2008

Mean Power

Traffic


Big Routers

Switch Core Linecards

1 2 3 4 5 6 7 8 9 10111213141516

17181920212223242526272829303132

131415161718

192021222324

252627282930

3132

1 2 3 4 5 6

7 8 9 101112

1 2 3 4 5 6 7 8 9 10111213141516

17181920212223242526272829303132

Up to 1000ft

Source: Nick McKeown http://yuba.stanford.edu/~nickm/


Structure of Switching Centres

© Nick McKeown 2006


Circuit switches control the topology SONET/SDH, DWDM


� Circuit switches are simple- “Start with a packet switch and throw 90% of it away”

� Circuit switches are well-suited to optics

But…

� Circuit switches are unfashionable


Conventional Wisdom


Circuit switching finally eliminated?


Dynamic Circuit Switches


Capacity on demand between edge routers

S. A. Paredes, T. J. Hall, ‘Flexible bandwidth allocation and scheduling in a packet switch with an optical core’, J. Optical Networks. 4 (5), 260-270 (2005), http://www.osa-jon.org/abstract.cfm?URI=JON-4-5-260/

Wei Yang, Sofia A. Paredes, Henry Schriemer, Trevor J. Hall, ‘Protection of Dynamic and Flexible Bandwidth on Demand in Metro Agile All-Optical Ring Networks’, J. Opt. Commun. Netw. 1, 2009, pp. A160-A169

Optics Departmentpage 27© Nick McKeown 2006

Will big routers be something of the past….?


Ubiquitous Wireless Access (Computer Scientist’s Dream)

Source: Vodefone Group PlC

Handsets

►Energy consumption of handsets

negligible in comparison to BS

consumption

► High churn may make manufacturing

/ disposal phase emissions significant?

Base Stations

► Only 5-10% of BS power is useful RF

emission.

► RF Power Amplifier ~ 45% efficient

► Cooling

Fans ~ 10-15% of BS power

Air Conditioning ~ 50% of BS power


Wireless Networks

Cellular Radio

� Provide mobile access to fixed network; backhauling

� Degrees of mobility

� Cellular Networks : handover

� …

Optics Department

Single or multiple antenna coverage ?

Low Density

of High Power transmitters

High Density

of Low Power transmitters

page 30

Multiple antennas offer lower total power for same coverage :

• if greater than 1/R² fall-off in radiated intensity (cluttered environments)

vs


Simulation Results: DAS vs Mono Antenna

•page 31

•Mono-Antenna SystemPropagation Model : DP ; Transmit Power : Pt = 10 dBm (Pout=100%); Antenna: EIRP=-2 dBm ; Channel : 1

•Maximum received Power (dBm) •Maximum Bit-rate (Mbit/s) •DAS

Propagation Model : DP ; Transmit Power : Pt = 1 dBm (Pout=25%) ; Antenna: EIRP=-17 dBm; Channel : 1, 6, 11

•Maximum received Power (dBm) •Maximum Bit-rate (Mbit/s)


Measurement results: DAS vs Mono Antenna

•page 32

•Mono-Antenna SystemPropagation Model : DP ; Transmit Power : Pt = 10 dBm (Pout=100%); Antenna: EIRP=-2 dBm ; Channel : 1

•Maximum received Power (dBm) •Maximum Bit-rate (Mbit/s) •DAS

Propagation Model : DP ; Transmit Power : Pt = 1 dBm (Pout=25%) ; Antenna: EIRP=-17 dBm; Channel : 1, 6, 11

•Maximum received Power (dBm) •Maximum Bit-rate (Mbit/s)

Optics Department

Resources on Demand

page 33


Directional links

� Sending power only where and when needed

• Increased power efficiency

• Increased complexity :- Multiple Target Pointing Acquisition and Tracking needed

Optics Department

Phased Array Radar

Electronic Beam Forming & MIMO

page 35

http://www.microwaves101.com/encyclopedia/phasedarrays.cfm

MIMO : Multiple Input Multiple Output

Optics Department

Two-dimensional optical phased array antenna

on silicon-on-insulator

page 36

Karel Van Acoleyen, Hendrik Rogier & Roel Baets, Optics Express, 18(13), 21 June 2010, pp. 13655-13660

Optics Department

Putting it together

� Broadband Services

• Higher frequency carriers (shorter wavelengths)

� Sophisticated antennas (MIMO)

• Shorter wavelengths for compactness (especially handsets)

� High density of antennas

• Simple remote stations (for low cost)

• Distribute signals from base stations / central stations via a network

• Keep data in the optical domain

� Energy Harvesting

⇒⇒⇒⇒

� Optical feeder network

• Remote powering and/or solar powered remote stations

• Solar powered handsets?

page 37

Optics Department

Radio-over-Fibre Technologies for Wireless Access

page 38 http://departements.telecom-bretagne.eu/optique/research/capilr/

Optical link

Picocell

◄ Pico-cellular wireless coverage with

optimized distribution of RF power in

indoor environments

▲Intelligent Light Poles for the distribution of

wireless services in outdoor environments

Optics Department

Numerous Architectural Options

page 39

• {Analog, Digital}, {BB, IF, RF} transmissions

• Local Oscillator signal distribution

E/O O/E

Central Station Access Point

Mobilef0

Optical fibre

Wireless Path

fRFRF RF

f0

f0

fc=fIF

fc=fRF

fc

BB

data

carrierRF

Baseband-over-Fibre

IF-over-Fibre

RF-over-Fibre Frequency up-down

conversion not required

Frequency up-down

conversion required

(de)modulation

required

Optics Department

Narrow line-width single & multiple frequency

lasers as sources of mm wave carriers

page 40

0.06 nm/°C

Optics Department

Thermoelectric Cooler (TEC)

� Operating frequency of optical devices is

sensitive to temperature.

� A TEC is commonly used to stabilise the

temperature of an optical component.

� A TEC is 5-10% efficient compared to an

ideal reversible heat engine.

� Several Watts of electricity is consumed to

cool devices that inherently dissipate

minimal power in comparison.

page 41

�Share TEC among many devices

�No integratable isolator

� Reference slave to master oscillators

� Locking techniques complex & expensive

�Athermal Design

� Challenging

http://en.wikipedia.org/wiki/Thermoelectric_cooling


Conclusions

� Business as usual in ICT is unsustainable

• Improved energy efficiency is necessary but not enough

• Need zero carbon solutions

� Power resources on demand

� Keep data in the optical domain

� Use (optical) circuit switching in the core banish IP to the edge

� Use optical backhaul for mobile access

� Deploy Radio-over-Fibre for mobile access

� Harvest renewable energy

� Grand challenges

• Directional rather than broadcast (optical) wireless

- Pointing acquisition and tracking?

• Green Optoelectronics

- Eliminate thermoelectric cooling & heating

- Nano-photonics to approach fundamental o-e-o conversion energy

consumption limits?

Optics Department

Can photonic network technology bring broadband

access to all and help save the planet?

� Yes, but paradigm-shifting solutions will be required.

Thank you!

page 43


SISCOM Chair Programme

� Missions & Events

• UK & Scandinavian Mission

• Green Radio over Fibre Workshops

� Joint supervision of students

• PhD student at Telecom Bretagne recruited

� Development of Laser Sources of mm-waves

• Canadian funding approved

� Progress CapilR Radio over Fibre Demonstrator

siscom chair inaugural lecture - imt...

Documents