energy metrics and figures of merit for planning ee .../file/etsi_eees... · merit for planning ee...
TRANSCRIPT
1/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Energy Metrics and Figures of Merit for Planning EE Communication Networks
Professor Timothy O’Farrell Chair of Wireless Communications Department of Electronic and Electrical Engineering The University of Sheffield, UK
2/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Presentation Outline • Introduction • Remarks on current EE framework • A new EE framework – Figures of Merit & Metrics • Radio Access Network case studies
• Macrocell densification • Microcell densification • HetNets vs. Small Cells
• Conclusions
3/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Introduction • Energy consumption is a concern in communication
networks, in particular in cellular mobile radio networks. • Despite intense global research since 2009, there still
isn’t a consistent evaluation framework for unambiguously comparing the EE of different network topologies for network planning purposes.
• For example, a question pertinent to 5G – “For best EE should only small cells be deployed or HetNets?” largely remains an open question!
4/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Current EE Framework Essentially, one joint “EE metric and figure of merit (FoM)” has emerged – the Energy Consumption Ratio (ECR). E is energy consumed, M is data volume The rational being EE relates useful output (bits) to energy consumed (J). Then, EE is measured in various forms:
ECR ! E
MJ Bit−1 EE = 1
ECR= ME
Bit J−1
EE = M /TE /T
= SP= Throughput
Power
5/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Remarks • Initially, E was the transmitted signal energy; later total
energy to account for the equipment overhead energy. • T is a common observation or coherence period. • The EE calculated depends on how S and P are defined
and where and when they are measured. • Some concerns when comparing networks:
• As E is total energy, E(M) = ECR x M is problematic (e.g. M = 0); • Between two network topologies, does the network with the
largest EE consume the least energy if the data volumes differ (i.e. M2 ≠ M1)
6/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
New EE Framework
RAN1
RAN2
E1
E2
{E1{o} M1 T | T1, P1, A1, n1, α1, C1}
{E2{o} M2 T | T2, P2, A2, n2, α2, C2}
O/P
Ene
rgy
I/P E
nerg
y
Dat
a vo
lum
e
Obs
erva
tion
Tim
e
BTS
Tx
dura
tion
BTS
cov
erag
e ar
ea
Num
ber o
f BTS
s
Tota
l BTS
Pow
er
BTS
Loa
d fa
ctor
BTS
mea
n ca
paci
ty
α i = Ti T {i = 1,2}
7/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Figures of Merit (FoM) • Consider a FoM based on the ratio ECR1:ECR2
• This suggests three essential FoMs
ECR1ECR2
= EE2EE1
= E1 M1
E2 M 2
= E1E2
× M 2
M1
Energy Ratio ER = E1
E2
, Throughput Ratio TR = M 2
M1
Joint Energy Throughput Ratio ETR = ER ×TR = E1
E2
× M 2
M1
8/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Remarks on FoM • ER compares energy consumption definitively. • TR compares data volumes definitively. • ETR is a joint FoM which compares energy consumption
if and only if TR = 1 (i.e. M2 = M1) since for this condition ETR = ER.
• Therefore, comparing network designs based only on EE defined in terms of ECR is problematic.
• We now require metrics for ER, TR and ETR.
9/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Metrics (Homogeneous, 1-sector cell plan) • For ETR:
• For TR:
since • For ER:
T = M1 n1α1C1
= M 2 n2α 2C2
⇒ TR = M 2
M1
≡ S2 A2S1 A1
Si =α iCi {i = 1,2} and n2 n1 = A1 A2
ER = ETRTR
= E1E2
≡ P1 A1P2 A2
ETR = ECR1ECR2
≡ P1 S1P2 S2
10/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Metrics
11/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
RAN Case Studies
Poh = Pac + Pbh + ns ⋅ Pps + Ppu{ }
Pbts =αPrh + Poh 0 ≤α ≤1
Prh = ns ⋅na Ptrx +Ptx
ηpa ⋅ηcl
⎧⎨⎪
⎩⎪
⎫⎬⎪
⎭⎪
C = B log2 1+1
αSIRmin
+ mkdγ N
GPtx
⎛
⎝
⎜⎜⎜⎜
⎞
⎠
⎟⎟⎟⎟
Cbts =1A
CdAA∫
12/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Macrocell Densification
Macrocell Baseline
ER TR ETR
RA
N E
R
RA
N T
R
RA
N E
TR
13/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Microcell Densification
Macrocell Baseline
ER TR ETR
RA
N E
R
RA
N T
R
RA
N E
TR
14/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Small cells vs HetNets
HN1 = Macro + Micro HN2 = Macro + Pico HN3 = Micro + Pico 10 MHz Macrocell benchmark
ER
TR
ETR
15/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Conclusions • Designing for EE RANs requires at least three FoMs (ER, TR and ETR) as
determined by three metrics (P/A, S/A and P/S). • Having an accurate power consumption model of the network equipment
(including backhaul) is essential to the design process. • IMEC/Greentouch power models (www.imec.be/powermodel) released 18 June 2015 -
Power model for today's and future base stations.
• And of HetNets vs. small cells? • HetNets (as in adding small cells to existing macrocell infrastructure) is more about
increasing capacity rather than reducing energy consumption. • Replacing macrocells with small cells can reduce energy consumption (up to a point) as well
as increase capacity.
• Some next steps: • Combining our analysis with ETSI ES 203228 in a Switzerland case study; • Adding cost km-2 as an additional FoM and metric.
16/16
© The University of Sheffield, Professor T. O’Farrell 31/05/15
Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, 3-5 June 2015, Sophia-Antipolis, France.
Thank you Questions? Acknowledgements: 1. Simon Fletcher, NEC Telecom MODUS, Leatherhead, Surrey, UK. 2. Konstantinos Samdanis, NEC Laboratories Europe, Heidelberg, Germany. [1] T. O’Farrell and S. Fletcher, “Green Communication Concepts, Energy
Metrics and Throughput Efficiency for Wireless Systems,” Green Communications: Principles, Concepts and Practice, First Edition, Edited by Konstantinos Samdanis, Peter Rost, Andreas Maeder, Michela Meo and Christos Verikoukis. © 2015 John Wiley & Sons, Ltd. Published 2015 by John Wiley & Sons, Ltd. (in print)