Core 5 Research Programme

1
Core 5 Research Programme Green Radio The Case
for More Efficient Cellular Base Stations May
2009 Peter Grant University of Edinburgh and
Mobile VCE Board Member
2
Core 5 Programme Green Radio Towards
Sustainable Wireless Networks May 2009 Peter
Grant UoE and Board Member Steve McLaughlin UoE
and Academic Co-ordinator Hamid Aghvami KCL and
Board Member Simon Fletcher NEC and Industrial
Steering Group Chair
3
Presentation Overview

• The Current Status on Cellular Systems
• The Business Case for Green Radio
• Defining the Green Radio Issues
• The Mobile VCE Research Programme
• Research Areas and Key Deliverables
• Conclusions

4
Why Green Radio?Operator Manufacturer
Perspective

• Increasing energy costs with higher base station
  site density and energy price trends
• A typical UK mobile network consumes 40MW
• Overall this is a small of total UK energy
  consumption, but with huge potential to save
  energy in other industries
• Energy cost and grid availability limit growth in
  emerging markets (high costs for diesel
  generators)
• Corporate Responsibility targets set to reduce
  carbon emissions and environmental impacts of
  networks
• Vodafone1 - Group target to reduce CO2 emissions
  by 50 by 2020, from 2006/07 levels
• Orange2 Reduce our greenhouse emissions per
  customer by 20 between 2006 and 2020

1. http//www.vodafone.com/etc/medialib/attachment
s/cr_downloads.Par.25114.File.tmp/CR20REPORT_UK-F
INAL20ONLINE_180908_V6.pdf 2. http//www.orange.c
om/en_EN/tools/boxes/documents/att00005072/CSR_rep
ort_2007.pdf
5
Where is the Energy Used?

• For the operator, 57 of electricity use is in
  radio access
• Operating electricity is the dominant energy
  requirement at base stations
• For user devices, most of the energy used is due
  to manufacturing

3. Tomas Edler, Green Base Stations How to
Minimize CO2 Emission in Operator Networks,
Ericsson, Bath Base Station Conference 2008
6
UK Network Consumption
Source CR review, Vodafone UK, Corporate
Responsibility 2007/08
7
UK Network Emissions??
Source CR review, Vodafone UK, Corporate
Responsibility 2007/08
8
Cellular Network Power Consumption Summary
(from previous pie chart)
Source Vodafone
9
Base Station Power Use _at_ 2003
H. Karl, An overview of energy-efficiency
techniques for mobile communication systems,
Telecommunication Networks Group, Technical
University Berlin, Tech. Rep. TKN-03-XXX,
September 2003. Online. Available
http//www-tkn.ee.tu-berlin.de/karl/WG7/AG7Mobiko
m-EnergyEfficiency-v1.0.pdf
10
Power Consumption
Power Consumption per BS
Now (Possible) Target (2010)
GSM 800W 650W
WCDMA 500W 300W
Source NSN
11
Energy Consumption

• The Base Station is the most energyintensive
  component of a 3G mobile network.
• A typical 3G Base Station consumes about 500 W
  with a output power of 40 W. This makes the
  average annual energy consumption of a BS around
  4.5 MWh (which is lower than a GSM BS).
• A 3G mobile network with 12,000 BSs will consume
  over 50 GWh p.a. This not only responsible for a
  large amount CO2 emission it also increases the
  system OPEX.
• This is worse in China with 10-20 times number of
  mobile subscribers!

12
Other wireless comparisons

• IEEE 802.11 Wi-Fi laptop access are only 1 2
  efficient when we compare radiated power to total
  required power load.
• (Transmit power of 20 100 mW for an AC power
  drain of 2 8 W)
• WWW.atheros.com/pt/whitepapers/atheros_power_white
  paper.pdf

13
Energy Consumption The Challenge

• Since 2006, the growth rate of data traffic on
  mobile networks has been approximately 400 p.a..
  It is expected to grow at least the same rate in
  coming years.
• This growth demands a much higher energy
  consumption than today.
• The challenge is how to design future mobile
  networks to be more energy efficient to
  accommodate the extra traffic.

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Green Radio as an Enabler

• Trends
• Exponential growth in data traffic
• Number of base stations / area increasing for
  higher capacity
• Revenue growth constrained and dependent on new
  services

• Energy use cannot follow traffic growth without
  significant increase in energy consumption
• Must reduce energy use per data bit carried
• Number of base stations increasing
• Operating power per cell must reduce
• Green radio is a key enabler for cellular growth
  while guarding against increased environmental
  impact

Traffic / revenue curve from The Mobile
Broadband Vision - How to make LTE a success,
Frank Meywerk, Senior Vice President Radio
Networks, T-Mobile Germany, LTE World Summit,
November 2008, London
15
2020 Vision Paper The Challenge

• The Mobile VCE Visions Group comprising global
  thoughts leaders in the industry articulated the
  need.

Arguably what is needed are wireless access
systems that can support multimedia service data
rates attwo or three orders of magnitude lower
transmission power than currently used.
Performance of todays radio access technologies
is in fact already approaching the Shannon Bound
such an advance will not come simply from more
traditional research on single aspects of the
physical layer, but will require holistic,
system-wide, breakthrough thinking that
challenges basic assumptions Mobile VCE
consultation paper, 2020 Vision Enabling the
Digital Future Dec07

• Mobile VCE Green Radio programme formulated to
• Take forward existing research
• Aim to achieve an international lead in this field

16
Broadband Traffic on Mobile Networks

• Revenue increase is not in line with traffic
  growth
• Average annual increase in traffic 400
• Average annual increase in revenue 23
• With the launch of HSDPA and the introduction of
  flat-rate pricing, data traffic is increasing
• Traffic is growing faster than the revenue
  increase
• The biggest traffic growth is seen at operators
  whose data pricing is more aggressive than the
  average

Source Stanley Chia, Workshop on As the
Internet takes to the air, do mobile revenue go
sky high?, IEEE Wireless Communications and
Networking Conference, April 2008.
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Possible Solutions Green Radio

• Can we benefit from the use of the information
  below in the design of future mobile networks?
• Mobility pattern (location, speed and direction
  of mobile user) information
• Characteristic of multimedia traffic (traffic
  classification)
• Transmission power scaling (distribution) in
  order to use renewable energy for BSs.

18
Green Radio Scenarios

• Two Market Profiles
• Developed World
• Developed Infrastructure
• Saturated Markets
• Quality of Service Key Issue
• Drive is to Reduce Costs
• Emerging Markets
• Less Established Infrastructure
• Rapidly Expanding Markets
• Large Geographical Areas
• Often no mains power supply power consumption
  a major issue
• Green Radio MVCE Book of Assumptions
• Defines cellular, enterprise home scenarios
• To galvanise targeted innovations

19

• Over a year, 1m2 solar panel produces 400 kWh
  energy, or about 10 of a 3G macrocell BS
  requirement (in London, lt 5).
• Note that we never recover the embodied or
  manufacturing energy!
• A combination of solar wind sources, in a good
  location may provide the energy requirement for a
  small (pico-femto) BS ?

20

• Industry Subscription/Gvt funded Collaboration
• Core 5 research programme, 2009 2012 targets
• Green Radio
• Flexible Networks
• User interactions

21
Mobile VCE Funding Model
New Products, Services Revenue Streams Seeds
Feedsin-houseRD One-way Trapdoor
UK Government Support Govt Funds
- - - Members Subscriptions - - -
Members Core Fund
Core Programme Funding
Industry led, University delivered World Class
Research Patents

• Excellent financial gearing for Industry Members
• Strengthens the UK research base, available to
  the global industry
• Known, qualified, research staff who appreciate
  industrys needs

22
GR Industrial Leadership Team

• ChairmanSimon Fletcher NEC

• Deputy Chairman Andy Jeffries Nortel

• Deputy Chairman David Lister Vodafone

Industry Steering Group participants so far
23
GR Academic Delivery Team
Prof. Steve McLaughlin (Academic
Co-ordinator) Dr. John Thompson Dr. Dave Laurenson
Prof. Tim O'Farrell Dr. Pavel Loskot Dr. Jianhua
He
Prof. Joe McGeehan Dr. Simon Armour Dr. Kevin
Morris
Prof. Hamid Aghvami Dr. Mohammad Reza Nakhai Dr.
Vasilis Friderikos
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GR Programme Objectives

• Strive to improve efficiency of base station
  operation with improved component designs
• Power amplifier
• Power efficient processing, e.g. DSP
• Sleep modes
• Backhaul redesign
• Improve overall system operation
• Multi-hop routing
• Relaying
• Improved resource allocation
• Dynamic spectrum access

25
Green Radio Programme Organisation
Industry Steering Group
Flexible Networks Program
Energy Focus Group
2 Technical Work Areas - 48 Man Years
26
Target Innovations Architecture

• Establishing Baselines To develop a clear
  understanding of energy consumption in current
  networks and the network elements, base sites,
  mobiles, etc for the scenarios defined in the
  Book of Assumptions
• Backhaul Options To determine the best backhaul
  strategy for a given architecture
• Deployment ScenariosTo determine what is the
  optimum deployment scenario for a wide area
  network given a clearly defined energy efficiency
  metric

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Architecture Technical Approach

• Energy Metrics Models
• Primary and derived energy metrics to accurately
  quantify consumption
• Communications energy consumption models for the
  radio access network (RAN) architecture
• Energy Efficient Architectures
• For RAN technology, compare large versus small
  cell deployment
• Assess scenarios for placement of relay nodes
• Efficient backhaul in support of identified
  architectures
• Multi-hop Routing
• Bounding energy requirements by strict end-to-end
  QoS
• Exploiting delay tolerant applications and user
  mobility for energy reduction
• Frequency Management
• Identification of energy efficient co-operative
  physical layer architecture using emerging
  information theory ideas to remove interference
• Applying Dynamic Spectrum Access (DSA) to
  minimize energy consumption by utilising bands
  with low interference
• Solar-powered relaying allocating resources to
  match combined traffic and weather patterns

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Architecture Energy Efficiency Analysis
Macro
Micro
Pico
Femto
Step1 Large vs. small cells applying the energy
metrics
Step2 Overlay Source Network Coding and/or
Cooperative Networking
Step3 Evaluate optimum cell size from the
following perspectives.
RRM
Packet scheduling, handover, power and load
control
BER/FER vs Eb/No
Differentiated QoS, fast fading effects, UE
speed, MIMO
Link Budget
Energy consumption is proportional to distance
Mobility/Traffic Models
User Equip (UE) movement, traffic types mixes
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Can We Reduce Power Consumption Through
Delay-Tolerant Networking?

• Conventional
• Cellular

2. In-Building Relay
3. Multi-hop Relay
4. Heterogeneous Relay
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Applying Network Element Deployment Perspective
Wide scope Macro-cells, relays, backhaul,
WLAN. Also consider Embodied (Equipment
Fabrication) Energy.
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Architecture
33 month Task researchers split to 3 areas
GR1-2 Performs Overall Architecture Assessment
Selection of Key Metrics Initial Results on
Efficient Architectures
9 month Task All researchers participate
Energy Efficient Architectures 8.75 MY
Key Metrics Architecture 3.5 MY
Multihop 6.25 MY
Frequency Management 3.75 MY
GR1-3 and 1-4 Address More Specific Issues
32
Target Innovations Techniques

• Overall Base Station Efficiency Techniques to
  deliver significant improvements in overall
  efficiency for base stations, measured as RF
  power out to total input power
• Improving the QoS/RF Power Ratio Reduce the
  required RF output power required from the base
  station whilst still maintaining the required QoS
• Optimization of a Limited Energy Budget Given a
  base station nominal daily energy requirement
  derived from renewable energy sources (e.g. 2.4
  kWh - 100W x 24hrs) determine how this would be
  best used for communication
• Scaling of Energy Needs with Traffic Sleep
  mechanisms that deliver substantial reduction in
  power consumption for base stations with low
  loads and develop techniques that allow power
  consumption to scale with load

33
Techniques Power Efficient Hardware

• 3G Base station efficiency
• Climate control 65
• Power supply 85
• PA / transceiver 45
• Feeder cables 50
• Advanced base station architectures
• Multi-mode and multi-standard
• Maximise equipment and base station re-use
• Integration allows energy reductions
• Masthead electronics avoids cable losses
• Target gt 20 overall efficiency
• Advanced power amplifier techniques
• Target gt 60 PA efficiency
• Develop envelope tracking method

Integrated remote radio antenna
Baseline overall efficiency 12

• Masthead PA eliminates feeder loss
• Integration avoids interconnect losses
• Passive thermal cooling

Hardware Integration Advanced PA Techniques
34
Techniques DSP and Radio Resource Management

• Interference Minimisation and Cancellation
• Making transmissions more robust to interference
  to reduce required transmit power levels
• Peer-to-peer communications between terminals can
  be exploited to share information about signals
  and interference to improve decoding and suppress
  interference
• RRM Techniques for Lower Power Consumption
• Maximising power efficient utilisation of LTE RBS
  co-operation and collaboration support.
• Robust Measurement reporting, Radio Bearer
  Configuration, Packet Scheduling, handover and
  Power and Load Control for energy efficient
  delivery
• Novel Approaches
• Network coding
• Application of Sensor network techniques, cross
  layer approaches grounded in standards (LTE,
  WiMAX)

35
Techniques
GR2-5 Allows for Top-Down System Perspective
This task can vary in size according to results
from GR2-1
Novel Techniques for Power Reduction 4.25 MY
Investigation Evaluation 4.5 MY
Resource Management 7 MY
Efficient Hardware 5 MY
Efficient DSP 6.5 MY
GR2-2, 2-3 and 2-4 Address Techniques across
Protocol Stack
36
Green Radio Deliverables

• Year 1
• Workshop to discuss architecture metrics and
  promising techniques for power reduction
• Executive Summary on energy and power efficiency
  metrics and tradeoffs
• Year 2
• Poster day presenting key results to date
• Reports on efficiency gains
• Year 3
• Reports on Programme achievements for both
  Architectures and Techniques Work Packages
• Executive summaries of all key outputs from the
  Programme

37
Our Process - engagement with Industrial Sponsors

• Monthly Co-ordination Steering Group (CSG)
  meetings
• Progress management (deliverables, patents,
  publications)
• Internal and outreach event organisation
• Quarterly Technical Steering Group (TSG) meetings
• Meetings at which all Industrials have the
  opportunity to engage with the Researchers on the
  detail of their research results
• Interdependent approach facilitated by well
  established MVCE processes with Core 5
  enhancements
• Encouraging exploration of synergies with
  Flexible Networks. Both programmes contain
  activities in
• Network coding, routing, adaptive and
  self-organisation
• Webex Internet-based interactions between
  Researchers and Industrials, especially valuable
  for overseas-based industrials
• WiKi - promoting high awareness of leading edge
  of key radio access standards LTE(-Advanced),
  802.16 (WiMAX), 802.11 (Wi-Fi) and leading edge
  green technologies through the WiKi
• Industrial Energy Focus Group leading the
  embodied energy debate
• Open publication (after review), build patent
  portfolio for royalty free access by our sponsors
  plus external exploitation

38
Energy Focus Group Concept
Relate to Real World
Book of Assumptions
Real World
Metrics
Real World Metrics
Metrics / Optimisation
Targeted Questions
Real World Costs
Evaluation Approach
Real World System Parameters
Real World Constraints
Problem Abstraction
Energy Focus Group
Architecture Study

• Terms of Reference
• Initially tightly coupled to Architecture
  Research Group
• Evolution of targeted questions
• Analysis abstraction for realistic industrial
  application
• What energy metrics do we use to ensure
  realistic configurations architectures result

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Example Meetings Diary for 2009

• For our Members and Researchers
• Education Day 30th April
• To brief the researchers on the state of the art
  in industry and bring everyone up to speed on the
  Programme.
• Industry Quarterly Steering Group TSG3 2nd July
• Metrics Workshop 9th September
• Review meeting for a key deliverable from the
  Architecture Research, all are welcome.
• Industry Steering Group TSG4 1st October
• Outreach Events
• Event prior to WWRF 4th May at FT-Orange, Paris
• Support for Femto Forum Research Day
• Aligned with the Femtocells World Summit, June
  23rd - 25th, London
• Discussions ongoing with the Femtoforum.

40
Conclusions

• Green technologies relevance to business and
  politics will only continue to increase, Green
  Radio offers timely Industry driven research.
• Green Radio is a 48 man year programme run over 3
  years that offers
• An in-depth and systematic study of architecture
  issues to identify trade-offs in energy efficient
  network design
• Evaluation of Techniques across the protocol
  stack to select most promising approaches to
  reduce power.
• Green Radio will provide insights of value to
• Operators considering the impact of Green for
  future networks deployments
• Equipment Vendors for identification of key
  techniques enabling green solutions.

41
Conclusions

• Growth in data transmission requirements for
  mobile broadband will not bring major revenue
  increase.
• Every industry has published CO2 reduction
  targets and the mobile and IT communities are not
  exempt.
• Power drain in base-station or access point is
  the major issue in many wireless systems.
• Green Radio promised to deliver benefit to the
  Cellular network Operators via the equipment
  supply chain vendors.
• We plan to research and investigate changes to
  the system architecture and develop advanced
  networking techniques to deliver these future
  more efficient Green Radio systems.

42
Thank you !
For further information please contact Simon
Fletcher E-mail Simon.Fletcher_at_EU.NEC.COM Te
l 44 1372 381824 or Steve McLaughlin
Steve.McLaughlin_at_ed.ac.uk
44 131 650 5578
Further information on MobileVCE contact Dr
Walter Tuttlebee, E-mail walter.tuttlebee_at_mobilev
ce.com Tel [phone] WWW www.mobilevce.co
m