Università degli Studi di Udine Wireless and Power Line Communications Lab
Lecture at IEEE VTS Chapter Thessaloniki, Greece 21 June, 2012
Power Line Communications: A Technology with Application from Smart Grids to In-vehicle Scenarios
Andrea M. Tonello
Distinguished lecturer IEEE VTS
Wireless and Power Line Communications Lab University of Udine, Italy
[email protected] www.diegm.uniud.it/tonello
© 2012 ‐ WiPli Lab ‐ Universita’ di Udine FareIEEE clicVehicular per modificare Technology lo stile Society del titolo(VTS)
A. Tonello 2 FareIEEE clicVehicular per modificare Technology lo stile Society del titolo(VTS)
A. Tonello 3 WirelessFare clic and per Power modificare Line Communication lo stile del titolo Lab
Andrea M. Tonello Milan Udine Aggregate professor at Univ. of Udine Vice‐chair IEEE TC‐PLC Venice Steering committee member IEEE ISPLC University of Udine: 17.000 students (in the top‐ten in 2011) Rome 15 Members – part of the Department of Electrical, Mechanical and Management Eng. (150+ members) Activities: Wireless and Power Line Communications . Communication theory and signal processing . Measurements and emulation . RF and base band prototyping . Home networking, smart grid, infomobility and vehicular technology Projects: several national and EU FP5‐FP7 projects
A. Tonello 4 Fare clic per modificareOutline lo stile del titolo
Applications of PLC
A look at the standards
Key issues for the successful development of PLC systems:
. Channel and noise characterization
. Physical layer techniques: existing solutions and what next
Final remarks
A. Tonello 5 Fare clic perApplication modificare Scenarios lo stile del titolo
Power lines are pervasively deployed Application of power line communications can be ubiquitous
–Broad band internet access –In‐Home networking –Smart grid applications –In‐Vehicle application
A. Tonello 6 Fare clicPLC per in modificarethe Distribution lo stile Grid del titolo
Distribution Domain INTERNET Network Operator Monitoring and control . Fault detection, monitoring of
MV/LV MV PLC HV/MV power quality and islanding effects substation station LV PLC Energy management
house MV PLC . Decentralized production and LV PLC MV/LV storage control
substation MV PLC building . Charging of electrical vehicles MV/LV LV PLC substation Smart meter reading house . Demand side management User domain . Demand response Distribution domain . Dynamic pricing . Acquisition of user behavior PLC provides an easy to install two way communication infrastructure User Domain Internet access The user domain is very important Smart home for the penetration of SG services . Home networking . Automation and control
A. Tonello 7 FareBroad clic per Band modificare and Narrow lo stile Band del PLC titolo
All these services and applications have different requirements: . Data rate, latency, robustness, energy efficiency
Both Narrow Band and Broad band PLC have a role . NB‐PLC: 3‐148.5 kHz (Cenelec band) and 3‐500 kHz (FCC/ARIB band) . BB‐PLC: 2‐30 MHz and beyond
It is believed that NB PLC is the right choice for SG applications. This is because: . Low data rates are required . Longer distances are covered by NB PLC signals . Cheap modems have to be deployed
BB PLC has been designed for internet access and home networking
A. Tonello 8 Fare clic per modificareIn‐Vehicle PLClo stile del titolo
In‐vehicle communications via DC/AC power lines: . Alternative or redundant communication channel (e.g., to CAN bus) . Command and control of devices and sensors . Multimedia services distribution (music, video, games, etc.) . Controlling the charging status of e‐cars
Benefits REF. A. B. Vallejo‐Mora, J. J. Sánchez‐Martínez,F.J.Cañete,J.A.Cortés,L.Díez, “Characterization and Evaluation of In‐Vehicle Power Line Channels”, Proc. of the IEEE Global . Weight reduction Telecommunications Conference (GLOBECOM) 2010, Dec. 2010. REF. M. Antoniali, A. M. Tonello, M. Lenardon, A. Qualizza, “Measurements and Analysis of . Lower the costs PLC Channels in a Cruise Ship,” in Proc. Int. Symp. on Power Line Commun. and Its App. (ISPLC’11), Udine, Italy, April 3‐6, 2011. REF. M. Antoniali, A. M. Tonello, “In‐car PLC Advanced Transmission Techniques,” in Proc. of the 5th Biennial Workshop on Digital Signal Processing for In‐Vehicle Systems, Kiel, Germany, September 2011.
A. Tonello 9 Existing Systems and Standards
A. Tonello 10 NarrowFare clic Band per modificare PLC Systems lo andstile Standardsdel titolo
Meters PRIME UPB & G.Hnem IEEE HomePlug PowerLine Insteon Konnex X10 CEBus Universal More G3‐PLC C&C Intelligent ITU‐T 9955 P1901.2 PLC bus (Enel, Metering Endesa) Command NB NB Home Automation and Automatic Meter Reading standard standard Control Proprietary EN50090 Single carrier Multicarrier Standard EN13321‐1 HomePlug Prime Proprietary Proprietary EIA‐600 Proprietary Open ERDF ITU IEEE body ISO/IEC Consortium Alliance Low data rate: Meter data rate: 14543 Project some kbits/s hundred ofCENELEC kbits/sCENELEC CENELEC CENELEC CENELEC A CENELEC A C A, B,C,D A, B,C,D Spectrum CENELEC C CENELEC B CENELEC B CENELEC A CENELEC A FCC ARIB FCC ARIB FCC FCC FCC
DCSK OFDM OFDM OFDM Spread differential D8PSK Modulation BPSK S‐FSK PPM PPM BPSK DQPSK QPSK ‐ Spectrum code shift DQPSK DBPSK 16‐QAM keying DBPSK
50 or 60 0.6 to 7.5 Up to 4800 34 to up to 1 Bit‐rate 2.4 kbps 1.2 kbps 8.5 kbps 240 bps 128 kbps ‐ bps kbps bps 240 kbps Mbps
CSMA/CA MAC ND CSMA CSMA/CD CSMA/CD ‐ CSMA/CA ‐ CSMA/CA CSMA/CA ‐ TDMA
A. Tonello 11 FareBroadband clic per PLCmodificare Systems lo and stile Standards del titolo
ITU-T G.hn HomePlug AV HP Green PHY HD-PLC IEEE P1901 ITU-T G.9960
HomePlug HomePlug High Definition PLC Standard body IEEE ITU Consortium Consortium Alliance
PLC, Coax, phone line: Multicarrier up to 100 MHz (BB) 2-28 Spectrum 2-28 MHz 2-28 MHz 2/4-28 MHz PLC: 100-200 MHz (PB) 2-60 MHz data rate: Coax: up to 100 MHz Over 200 Mbits/s (PB, Fc=0.35-2.45 GHz) OFDM (HPAV) (3072 tones) OFDM Wavelet OFDM Bit-loading OFDM Modulation (1536 tones) (512 tones) Up to 4096- (up to 4096 tones) OFDM Bit-loading Bit-loading QAM Bit-loading & (1536 tones) Up to 1024-QAM Up to 16-PAM W-OFDM Up to 4096-QAM QPSK Coding Convolutional, RS, Convolutional, (HD-PLC) Turbo codes LDPC (1024 tones) LDPC Bit-loading Up to 32-PAM >200 Mbps Bit-rate 200 Mbit/s 3.8-9.8 Mbit/s 190 Mbit/s 540 Mbit/s Up to 1Gbps TDMA- MAC TDMA-CSMA/CA CSMA/CA TDMA-CSMA/CA TDMA-CSMA/CA CSMA/CA
A. Tonello 12 Channel Characteristics
The knowledge of the channel is important to design and test PLC systems
A. Tonello 13 Fare clic Channelper modificare Characteristics lo stile del titolo
In general the channel exhibits – Multipath propagation due to discontinuites and unmatched loads – Frequency Selective Fading – Cyclic time variations due to periodic change of the loads with the mains frequency (mostly bistatic behaviour in home networks)
A. Tonello 14 Fare clicA per Look modificare at the Topologies lo stile del titolo
Distribution Grid In-home Grid
High Voltage: 110-380 kV HV/MV length ~100 km HV/MV station station Main Medium Voltage: 10-30 kV length 5-10 km panel
MV/LV MV/LV MV/LV substation substation substation
1 L2 L3
L1 N 9 14 7 LV supply cable max length 1 km 400 V L-L ell 16 230 V L-N y c s pl se up ou s 0 h 30 ~ 23 30 21 The distribution system is divided in Layered tree structure from the supply cells with a number of houses main panel with many branches connected to a MV/LV substation. andoutletsfedbyderivation Structure depends on the country boxes
A. Tonello 15 FareIn‐Home clic per Channel modificare from loMeasurements stile del titolo
Path Loss Phase 20 50
0 0
-20
-50 -40
-60
Phase (rad) -100 Path Loss (dB) Path
-80
-150 -100
-120 -200 0 20 40 60 80 100 0 20 40 60 80 100 Frequency (MHz) Frequency (MHz) On average The phase is uniformly distributed – Frequency increasing attenuation The average phase is not linear at low Strong fading effects frequencies –Average channel gain is log‐normal
A. Tonello 16 FareRelations clic per between modificare Metrics lo stile (In del‐Home) titolo
The higher the channel attenuation, the higher the delay spread Coherence bandwidth is an hyperbolic function of the delay spread Data from campaigns in Italy, in France, in USA, and in Spain 1 3000 2 - 100 MHz Italy 0.9 2 - 100 MHz Italy 2 - 30 MHz Italy 2500 0.8 State (Band in MHz) ACG (dB) RMS‐DS ( s) CB (kHz) 2 - 30 MHz US 0.7 2Italy - 30 MHz (2 –Spain 100) ‐35.75 0.32 301 s) 2 - 100 MHz Italy
2000
= 0.9) (kHz) 2 - 100 MHz Italy
0.6 France (2 – 100) ‐ 0.21 310 2 - 100 MHz France 0.5 Italy (2 – 30) ‐32.381500 0.36 226 0.4 US (suburban) (2 – 30) ‐ 48.9 0.52 ‐ 1000
RMS-Delay Spread ( 0.3 Spain (2 – 30) ‐30 0.29 ‐ 0.2 Coherence Bandwidth ( 500 0.1
0 0 -60 -50 -40 -30 -20 -10 0 0 0.2 0.4 0.6 0.8 1 Average Channel Gain (dB) RMS-Delay Spread (s)
REF. M. Tlich, A. Zeddam, F. Moulin, F. Gauthier, “Indoor Power‐Line Communications Channel Characterization Up to 100 MHz – Part II: Time Frequency Analysis,” IEEE Trans. Power Del., 2008. REF. S. Galli, “ASimpleTwo‐Tap Statistical Model for the Power Line Channel,” in Proc. of ISPLC 2010. REF. F. J. Cañete, J. A. Cortés, L. Díez, J. L. G. Moreno, “On the Statistical Properties of Indoor Power Line Channels: Measurements and Models,” in Proc. of ISPLC 2011. REF. F. Versolatto, A. Tonello, "On the Relation Between Geometrical Distance and Channel Statistics in In‐Home PLC Nets.," in Proc. of IEEE ISPLC 2012
A. Tonello 17 FareOutdoor clic per LV modificare vs. In‐Home lo PLCstile Channel del titolo
Comparison between OPERA (Open PLC European Research Alliance) reference channels and a typical In‐Home channel
0 In‐Home channels have high -20 frequency selectivity and -40 low attenuation -60 –Veryhigh number of branches, -80 150 m discontinuities and unmatched -100 loads -120
Path Loss (dB) Loss Path In-Home –Short cables -140 Outdoor LV Outdoor LV channels have -160 350 m 250 m
-180 high attenuation but
-200 negligible fading 0 10 20 30 40 50 frequency (MHz) – Cable attenuation dominates REF. M. Babic et al., “OPERA Deliverable D5. Pathloss as a Function of Frequency, Distance and Network Topology for Various LV andMVEuropeanPowerlineNetworks,” 2005.
A. Tonello 18 Fare clic perOutdoor modificare MV Channel lo stile del titolo
MV channels exhibit in general (but not always) lower attenuation than Outdoor LV PLC – Further investigations have to be done Coupling effects have also to be considered Size is an issue if used in Inductive coupling MV/HV lines simplifies installation but has lower pass behavior
Capacitive coupling in MV lines, courtesy of RSE Inductive coupling in MV lines, courtesy of RSE
REF. A. Tonello, et al. “Analysis of Impulsive UWB Modulation on a Real MV Test Network,”inProc.IEEE Int. Symp. on Power Line Commun. and Its App. ISPLC’11, Apr. 2011.
A. Tonello 19 FareIs it clic Possible per modificare to Model lothe stile Channel del titolo ? The channel can be accurately modeled with two approaches: – Top‐down: – Bottom‐up: analytic model fitted with from topology to channel response data from measurements using transmission line theory
Both approaches can be used to obtain a statistical model which is fundamental to test algorithms, predict performance, and plan deployment Top‐down in‐home model available at REF. A. Tonello, F. Versolatto et al. “A Fitting Procedurewww.diegm.uniud/tonello to Statistically Model the PLC Channel,” IEEE Trans. Power Del. 2012. REF. A. Tonello, F. Versolatto, “Bottom‐up Statistical PLC Channel Modeling – Part I: Random Topology Model and Efficient Transfer Function Computation,” IEEE Trans. Power Del., Apr. 2011. REF. A. Tonello, F. Versolatto, “Bottom‐up Statistical PLC Channel Modeling – Part II: Inferring the Statistics,” IEEE Trans. Power Del., Oct. 2010.
A. Tonello 20 Fare Backgroundclic per modificare Noise Comparison lo stile del titolo
Noise PSD Comparison -90
In-Home (worst) In‐Home PLCs experience the -100 Outdoor Low Voltage Outdoor Medium Voltage highest level of noise -110 Noise is much higher at low -120 frequencies -130
PSD (dBm/Hz) -140
-150 NB PLC exhibits higher noise
-160 than BB PLC
0 10 20 30 40 50 Frequency (MHz)
Background noise has an exponential PSD Narrowband interference –FM disturbances (> 87.5 MHz), AM (< 1.6 MHz), Radio amateur (from 1.9 MHz) Impulsive noise, noise introduced by devices (inverters, switching power supplies, fluorescent lamps, motors, etc.)
A. Tonello 21 FareRelations/Differences clic per modificare lowith stile Wireless del titolo
The channel is a shared medium both in PLC and Wireless
The channel is low pass with pass band below 300 MHz in PLC
Multipath propagation in both PLC and Wireless
Frequency response is approximately log‐normal in PLC as for path‐loss in wireless
Time variations are cyclic in PLC (no mobility)
Colored background and impulsive noise are present in PLC
A. Tonello 22 Physical Layer Signal processing algorithms are fundamental to overcome the channel impairments
A. Tonello 23 State‐of‐the‐art PLC Deploys Fare clic perMulticarrier modificare Modulation lo stile del titolo
b(k)(mN): QAM data symbols g(k)(n): sub‐channel pulses, obtained from the modulation of a prototype pulse N: interpolation factor N ≥ M number of sub‐channels
A. Tonello 24 Fare clic per modificareNotching lo stile del titolo
It is important to: . Transmit with low power so that the common mode currents that generate radiated fields are limited . Notch the spectrum to grant coexistence with other systems -40
-60 HPAV spectrum -80
PSD (dBm/Hz) -100
5 10 15 20 25 (a) Frequency (MHz) -20
-30 -40 G3 spectrum -50
PSD (dBm/Hz) -60
-70 20 30 40 50 60 70 80 90 100 (b) Frequency (kHz)
A. Tonello 25 FareSpectrum clic per modificare of OFDM and lo stile PS‐OFDM del titolo
OFDM PS-OFDM 0 0
-10 -10
-20 -20
-30 -30 (dB) 2 (dB) 2 -40 -40 |G(f)| |G(f)| -50 -50
-60 -60
-70 -70
-80 -80 -4 -3 -2 -1 0 1 2 3 4 -4 -3 -2 -1 0 1 2 3 4 f MT f MT OFDM uses a rectangular pulse (poor sub‐channel frequency confinement) PS‐OFDM uses a window, e.g., raised‐cosine, to fulfill the notching mask with a larger number of active tones
A. Tonello 26 Fare clic Filterper modificare Bank Approaches lo stile del titolo
Can we increase the sub‐channel frequency selectivity ?
. Yes, by privileging the frequency confinement
What schemes are available ?
. Wavelet OFDM (one solution adopted by IEEE P1901) . Filtered Multitone Modulation (FMT) . Other filter bank modulation approaches are also possible
A. Tonello 27 Fare clic per modificareFMT Basics lo stile del titolo
0
-10
-20
-30 (dB) 2 -40 |G(f)| -50
-60
-70
-80 -4 -3 -2 -1 0 1 2 3 4 f MT Pulses obtained from modulation of a prototype pulse . Time/Frequency confined pulses . Perfect reconctruction solutions provided that N > M REF. G. Cherubini, E. Eleftheriou, S. Olcer, “Filtered multitone modulation for very high‐speed digital subscriber lines,” IEEE J. Select. Areas Comm. 2002. REF. A. Tonello, F. Pecile, “Efficient Architectures for Multiuser FMT Systems and Application to Power Line Communications,” IEEE Trans. on Comm. 2009. REF. N. Moret, A. Tonello, "Design of Orthogonal Filtered Multitone Modulation Systems and Comparison among Efficient Realizations," EURASIP Journal on Advances in Signal Processing, 2010.
A. Tonello 28 AchievableFare clic per Rate modificare as a Function lo stile of N.del of titolo Tones Masked 2-100 MHz Masked 2-28 MHz Ave rage SNR=24 dB Ave rage SNR=24 dB
Pulse-Shaped OFDM Pulse-Shaped OFDM Target notching mask 160 FMT Equal. 1 Tap FMT Equal. 1 Tap below 30 MHz: HPAV 500 FMT FS Equal. 2 Taps FMT FS Equal. 2 Taps Notching Mask -40 FMT FS Equal. 10 Taps FMT FS Equal. 10 Taps 140 -50 FMT FS Equal. 20 Taps FMT FS Equal. 20 Taps -60 450
-70
PSD [dBm/Hz] PSD 120 -80
-90 FMT 0 10 20 30 40 50 60 70 80 90 100 400 s] f [MHz] / FMT 100 350 80
300 Achievable Rate [Mbit Rate Achievable Achievable Rate [Mbit/s] 60
250 PS‐OFDM PS‐OFDM FMT outperforms PS‐OFDM 40
200 20 The lower the SNR the higher is the advantage of FMT w.r.t. PS‐OFDM
150 0 M (Overall System Carriers) M (Overall System Carriers) FMT has better notching capability 256 512 256 512 1024 2048 4096 1024 2048 4096 REF. "Chapter 5: Digital Transmission Techniques," Power Line Communications, Theory and Applications for Narrowband and BroadbandFMT Communications achieves over the Power maximum Line, L. Lampe, rate E. Ferreira, with J. Newbury, a smaller (ed.s), number 2010, John Wiley of & tones Sons
A. Tonello 29 FareHow clic Can per We modificare Increase Performancelo stile del titolo ?
Increase bandwidth – up to 100 MHz or even above for BB PLC – up to 500 kHz for NB PLC Use powerful channel coding Perform adaptation of the transmitter parameters: –bit and power loading – adaptive scheduling (exploiting cyclic SNR variations) –cognitive use of spectrum Use MIMO transmission
A. Tonello 30 Fare clicAdaptive per modificare OFDM andlo stile FMT del titolo
We can adapt the pulse shape and the overhead β = N‐M such that capacity is maximized
æöSINR(k )(b) 1 ç ÷ Rbits()b =+å log2 ç 1÷ [] / ()MT+Gb ç ÷ kKÎ ON èøç For example, in CP‐OFDM we adapt the CP to the channel response
CP t
CP t
CP channel response t
REF. A. Tonello, S. D’Alessandro, L. Lampe, “Cyclic Prefix Design and Allocation in Bit‐Loaded OFDM over Power Line Communication Channels,” IEEE Trans. on Communications, Nov. 2010.
A. Tonello 31 Physical Layer Techniques
Can we use other modulation techniques ?
A. Tonello 32 Fare clic Impulsiveper modificare UWB: lo I‐ stileUWB del titolo
For low data rate: Impulsive UWB
PSD of the Transmitted Signal and Noise -70
-80
. Gaussian monocycle D=50‐200 ns, -90 Signal Tf = 2 us, R = 0.5 Mpulses/s. -100 . Symbol energy is spread in frequency by -110
the monocycle (frequency diversity) PSD (dBm/Hz) -120 In-Home Noise . The monocycle is spread in time via a -130 binary code (time diversity) -140 -150 0 20 40 60 80 100 . Coexistence with broadband systems is Frequency (MHz) possible due to the low PSD and high processing gain REF. A. Tonello, “Wideband Impulse Modulation and Receiver Algorithms for Multiuser Power Line Communications,” EURASIP Journal on Advances in Signal Processing, vol. 2007, pp. 1‐14.
A. Tonello 33 FareComparison clic per modificare of I‐UWB withlo stile NB del‐OFDM titolo I‐UWB may be suitable also for outdoor communications –Same transmitted power: higher data rates with I‐UWB w.r.t. NB‐OFDM –Same data rate: very low transmitted PSD with I‐UWB G3 Bandwidth = 54.7 kHz, PRIME Bandwidth = 46.9 kHz (here, only G3 because they perform similarly) MV Scenario O-LV Scenario 1
0.9
0.8
0.7 AVG RATE 3.9 kbit/s 0.6
0.5 CDF
0.4
0.3 AVG RATE 114.8 kbit/s
0.2
Power Gain 0.1 with Equal Target Capacity Equal Target Capacity Power Constraint 0 -120 -100 -80 -60 -40 -20 -100 -80 -60 -40 -20 PSD (dBm/Hz) PSD (dBm/Hz) max max REF. A. Tonello, et al. “Comparison of Narrow‐Band OFDM PLC Solutions and I‐UWB Modulation over Distribution Grids,” in Proc. IEEE Smart Grid Communications Conference, Oct. 2011.
A. Tonello 34 FareRelations/Differences clic per modificare lowith stile Wireless del titolo
Filter bank modulation is a solution for high speed communications both in PLC and wireless
UWB is a wireless technology but it may have some application also in PLC with smaller bands and data rate, though
Chanel coding solutions developed for wireless are applied also in PLC, e.g., convolutional, turbo and LDPC codes
Adaptation and cognitive techniques are important in PLC
MIMO is not clear yet whether it has a role in PLC
A. Tonello 35 Conclusions and Evolution of PLC
A. Tonello 36 Fare clic per modificareConclusions lo stile del titolo PLC technology has reached a certain maturity –The in‐home BB market is significantly increasing –PLC will play an important role in the SG (both NB and BB PLC) –PLC for in‐vehicle has many benefits but little work done so far
Importance of definition of applications and requirements in the SG (many domains) –Is AMR/Smart metering the killer application ?
Coexistence of technologies is fundamental
Harmonization of standards needs to be completed for mass deployment
A. Tonello 37 Fare clic per modificareEvolution lo stile del titolo
EMC, coexistence/interoperability mechanisms also with other technologies Advances at the PHY, e.g., . filter bank modulation, MIMO, optimal channel coding, mitigation of interference and impulsive noise…. Advances at the MAC, e.g., . adaptation and applicable resource allocation algorithms, cooperative techniques, … New grid topologies, new cables, and possible new bandwidths might come out It is important to perform channel characterization and modeling … and I enjoy doing that !
A. Tonello 38 Fare clicDissemination per modificare Opportunities lo stile del titolo
A. Tonello 39 Fare clic perInterested modificare in loPLC stile ? del titolo
IEEE ComSoc Technical Committee on PLC . Chair. L. Lampe, Vice‐chair A. Tonello, Secretary V. Guillet . http://committees.comsoc.org/plc
Sponsors IEEE ISPLC, the annual WSPLC and is involved in other conferences: Globecom, ICC, SmartGridComm,…
Developed DocSearch and paper repository
PLC best readings: http://www.comsoc.org/BestReadings/Topic/PLC
A. Tonello 40 Fare clic per modificare lo stile del titolo
Ευχαριστω !
A. Tonello 41