SRC GRC Annual Review - PowerPoint Presentation

Presentation on theme: "SRC GRC Annual Review"— Presentation transcript

Slide1

SRC GRC Annual ReviewMarch 8, 2011

Powerline Communicationsfor Enabling Smart Grid Applications

Prof. Brian L. Evans

Wireless Networking and Communications Group

The University of Texas at AustinSlide2

Task ID 1836.0632

Task Description:Increase powerline communication (PLC) data rate for better monitoring/control applications for residential and commercial energy usesAnticipated Results: Adaptive methods and real-time prototypes to increase bit-rates in PLC networksPrimary Investigator:

Prof. Brian L. Evans, The University of Texas at Austin

Current Students

Current Status

Ms. Jing Lin Ph. D (expected graduation in May 2014)

Mr. Yousof Mortazavi Ph. D (expected graduation in Dec. 2013)

Mr. Marcel Nassar Ph. D (expected graduation in May 2012)

Industrial Liaisons:

Dr.

Anand Dabak

(Texas Instruments), Mr. Leo Dehner (Freescale),

Mr. Michael Dow (Freescale) and Mr. Frank Liu (IBM)

Starting Date:

August 2010Slide3

Task Deliverables3

Data and algorithms for receiver synchronization, channel measurements and modeling, and asynchronous impulsive noise mitigation (12/2010)Single-transmitter single-receiver (1x1) powerline communication system testbed: software package and documentation (5/2011)Data and algorithms for multichannel transmission for a three-transmitter single-receiver (3x1) powerline communication system (12/2011)Three-transmitter single-receiver (3x1) powerline communication system testbed: software package and documentation (5/2012)

Data and algorithms for crosstalk cancellation and low-power medium access control scheduling algorithms (12/2012)

Three-transmitter three-receiver (3x3) powerline communication system testbed: software package and documentation (5/2013)Slide4

Executive SummaryAccomplishments

Investigated PLC standardsLiterature survey on powerline channel/noise characterizationBuilt software and hardware framework for the PLC testbedSimulated receiver frame synchronization using chirp signal

Current work

Asynchronous impulsive noise mitigation algorithms

Future directions

Smart hand-shaking mechanisms between transmitter and receiver on the best sub-band (with high SNR) for transmission

Algorithms for synchronous impulsive noise mitigation

Noise and channel modeling and analysis

4Slide5

Background: Smart Grid Big Picture

Smart car : charge of electrical vehicles while panels are producing

Long distance communication

: access to isolated houses

Real-Time

: Customers profiling enabling good predictions in demand = no need to use an additional power plant

Any disturbance due to a storm : action can be taken immediately based on

real-time information

Smart building

: significant cost reduction on energy bill through remote monitoring

Demand-side management

: boilers are activated during the night when electricity is available

Micro- production

: better knowledge of energy produced to balance the network

Security features

Fire is detected : relay can be switched off rapidly

Source: ETSI

5Slide6

Background: Voltage Levels in Grid

Medium-Voltage

Low-Voltage

High-Voltage

Source: ERDF

6

“Last mile” PLC communications on low/medium voltage line

ConcentratorSlide7

Motivation for “Last Mile” PLC

Source: Powerline Intelligent Metering Evolution (PRIME) Alliance Draft v1.3E7

Concentrator controls medium to subscriber meters

Similar to wireless communications basestation

Applications

Automatic meter reading (right)

Smart energy management

Device-specific billing (plug-in hybrid)

Improving reliability and rate

Mitigate impulsive noise

Transmit over multiple phases

Standards target ~100 kbps

ERDF G3-PLC [Électricité Réseau Dist. France]

PoweRline Intelligent Metering Evolution

(PRIME) Alliance

7Slide8

PRIME Standard: Physical LayerOrthogonal Frequency Division Modulation (OFDM)

Divides transmission band into many narrow sub-channels

Transmission Band

42-89 kHz

Baseband sampling rate

250kHz

Subcarrier spacing

488.28125Hz

Number of subcarriers

256

FFT size

512 samples

Cyclic prefix length

48 samples

Number of data tones

84 (header) / 96 (payload)

Number of pilot tones

13 (header) / 1 (payload)

Subchannel constellation

Phase-shift keying (2, 4 or 8 levels)

Coding

convolutional coding (rate ½)

Max bit rate (uncoded)

42.9kbps, 85.7kbps, 128.6kbps

8Slide9

ChallengesPowerline Channel Impairments

Multipath and frequency-selective time-variant channel attenuationBackground noise, impulsive noise, and narrow-band interference

9

Source: Texas InstrumentsSlide10

Challenges (cont.)Performance degradation due to crosstalk

Induced by energy coupling across the phases or wires

Half-duplex operation eliminates ECHO and NEXT

Without FEXT cancellation, achievable data rate is significantly degraded

10Slide11

Presentation RoadmapFramework of PLC Testbed

Receiver frame synchronization using a chirp signalModeling of PLC channel noise11Slide12

PLC TestbedFramework of the 1X1 Bidirectional PLC Testbed

12

Hardware

Software

National Instruments (NI) embedded computers process streams of data.

National Instruments ADC/DAC generates/receives analog signals.

Texas Instruments analog front end enables half-duplex operation.

Transceiver algorithms implemented as C++

dynamically linked library, running in real-time embedded processors

Desktop PC running LabVIEW provides GUI for configuring and displaying key system parametersSlide13

Receiver Synchronization Using ChirpPRIME specifies a preamble to begin each burst.

Preamble is a linearly frequency modulated chirp over 42-89 kHzChirp has constant envelope (in contrast to an OFDM signal)Received signal

Correlated with chirp to find start of burst

Used to characterize channel

13Slide14

Experimental Results for SynchronizationTexas Instrument Development Kit for PLC

Two modems communicate with each other in interleaved mannerGather samples at 250 kS/s14

Rx

Rx

Tx

Tx

)Slide15

One Received Signal Burst

Preamble - - - - - - - Payload - - - - 

Header 1

Header 2

 

2.048

 -

each OFDM symbol is 2.240 ms

- 

In time domain, a burst has the following structure.Slide16

Frame Synchronization by Correlation

[Bumille & rLampe]

Linear scale

Log scaleSlide17

Chirp in Freq. Domain for Channel Est.

FFT length is 512Slide18

Ex. Decoding Second Header Symbol18

Looking at positive subcarriers onlyBPSK modulated subcarriers (Information in phase)Slide19

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]19

Source: Broadband Powerline Communications: Network DesignSlide20

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]20

Colored Background Noise:

PSD decreases with frequency

Superposition of numerous noise sources with lower intensity

Time varying (order of minutes and hours)

Source: Broadband Powerline Communications: Network DesignSlide21

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]21

Narrowband Noise:

Sinusoidal with modulated amplitudes

Affects several

subbands

Caused by medium and shortwave broadcast channels

Source: Broadband Powerline Communications: Network DesignSlide22

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]22

Periodic Impulsive Noise Asynchronous to Main:

50-200kHz

Caused by switching power supplies

Approximated by

narrowbands

Source: Broadband Powerline Communications: Network DesignSlide23

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]23

Periodic Impulsive Noise Synchronous to Main:

50-100Hz, Short duration impulses

PSD decreases with frequency

Caused by power convertors

Source: Broadband Powerline Communications: Network DesignSlide24

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]24

Asynchronous Impulsive Noise

:

Caused by switching transients

Arbitrary

interarrivals

with micro-millisecond durations

50dB above background noise

Source: Broadband Powerline Communications: Network DesignSlide25

PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types

[Zimmermann 2000]25

Source: Broadband Powerline Communications: Network Design

Can be lumped together as Generalized Background NoiseSlide26

Generalized Background Noise26

Source: Broadband Powerline Communications: Network Design

Power spectral density of generalized background noise

 Slide27

Impulsive NoiseAsynchronous noise dominates this class of noise

27Source: Broadband Powerline Communications: Network Design

Need to statistically model two aspects:

Impulse amplitude distribution

Inter-arrival time between impulsesSlide28

Asynchronous Impulsive Noise ModelingAmplitude statisticsClass-A Middleton

[Umehara]Weibull Distribution [Umehara]Empirical Fits [Zimmermann]

Interarrival statistics

Exponential distribution

[Zimmermann]

Empirical Fits

[Zimmermann]

Partitioned Markov chains

[Zimmermann]

28

Source: Zimmermann

Source: ZimmermannSlide29

Preliminary Noise Measurement29Slide30

Preliminary Noise Measurement30

Colored Background

NoiseSlide31

Preliminary Noise Measurement31

Colored Background

Noise

Narrowband NoiseSlide32

Preliminary Noise Measurement32

Colored Background

Noise

Narrowband Noise

Periodic and

Asynchronous Noise Slide33

List of Acronyms/Abbreviations

Acronym/Abbreviation

Meaning

Cyc. Pref.

Cyclic Prefix

FEC

Forward Error Correction

FEXT

Far-end crosstalk

LV/MV

Low-voltage / medium-voltage

MAC

Medium Access Control

MIMO

Multi-Input Multi-Output

NEXT

Near-end crosstalk

OFDM

Orthogonal Frequency Division Multiplexing

PAPR

Peak to average power ratio

PHY

Physical layer

PSD

Power Spectral Density

SFSK

Spread Frequency Shift Keying

33Slide34

ReferencesBumiller and Lampe, “Fast Burst Synchronization for PLC Systems,”

Proc. IEEE Int. Sym. Power Line Comm. and its Applications, 2007, pp. 65 - 70H. Hrasnica, A. Haidine, and R. Lehnert, Broadband Powerline Communications: Network Design, Wiley 2004.

A. G. Olson, A. Chopra, Y. Mortazavi, I. C. Wong, and B. L. Evans, “Real-Time MIMO Discrete Multitone Transceiver Testbed”,

Proc. Asilomar Conf. on Signals, Systems, and Computers,

Nov. 4-7, 2007, Pacific Grove, CA.

D. Umehara, S. Hirata, S. Denno, and Y. Morihiro, “Modeling of impulse noise for indoor broadband power line communications”,

Proc. IEEE Int. Sym. on Information Theory and Its Applications

, Oct. 29-Nov. 1, 2006, pp. 195-200.

M. Zimmermann and K. Dostert, "Analysis and modeling of impulsive noise in broad-band powerline communications,”

IEEE Trans. on Electromagnetic Compatibility

, vol.44, no.1, pp.249-258, Feb 2002.

Freescale solutions for smart metering and smart grid enablement,

http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=02430Z6A10

Texas Instruments Powerline Communications solutions

http://www.ti.com/ww/en/apps/power_line_communications/index.html?DCMP=plc&HQS=Other+OT+plc

34