POWERLINE COMMUNICATIONS FOR ENABLING SMART GRID APPLICATIONS Task ID: 1836.063 Prof. Brian L. Evans Wireless Networking and Communications Group Cockrell School of Engineering The University of Texas at Austin bevans@ece.utexas.edu http://www.ece.utexas.edu/~bevans/projects/plc May 3, 2012

Principal Investigator: Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Task Description: Improve powerline communication (PLC) bit rates for monitoring/controlling applications for residential and commercial energy uses Anticipated Results: Adaptive methods and real-time prototypes to increase bit rates in PLC networks Principal Investigator: Prof. Brian L. Evans, The University of Texas at Austin Current Students (with expected graduation dates): Ms. Jing Lin Ph.D. (May 2014) Mr. Yousof Mortazavi Ph.D. (Dec. 2012) Mr. Marcel Nassar Ph.D. (Dec. 2012) Mr. Karl Nieman Ph.D. (May 2014) Industrial Liaisons: Dr. Anand Dabak (TI), Mr. Leo Dehner (Freescale), Mr. Michael Dow (Freescale), Mr. Frank Liu (IBM) and Dr. Khurram Waheed (Freescale) Starting Date: August 2010

Task Deliverables Date Tasks Dec 2010 Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Task Deliverables Date Tasks Dec 2010 Uncoordinated interference in narrowband PLC: measurements, modeling, and mitigation May 2011 Single-transmitter single-receiver (1x1) PLC testbed Dec 2011 Narrowband PLC channel and noise: measurements and modeling On-going Two-transmitter two-receiver (2x2) PLC testbed Narrowband PLC noise mitigation

Smart Grid: Big Picture Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Smart Grid: Big Picture Long distance communication : access to isolated houses Real-Time : Customers profiling enabling good predictions in demand = no need to use an additional power plant Micro- production: better knowledge of energy produced to balance the network Demand-side management : boilers are activated during the night when electricity is available Smart building : significant cost reduction on energy bill through remote monitoring Any disturbance due to a storm : action can be taken immediately based on real-time information Security features Fire is detected : relay can be switched off rapidly Smart car : charge of electrical vehicles while panels are producing Source: ETSI

Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Power Lines Built for unidirectional flow of power and not for bidirectional communications High Voltage (HV) 33 kV – 765 kV Medium Voltage (MV) 1 kV – 33 kV Low Voltage (LV) under 1 kV Concentrator (Transformer) Source: Électricité Réseau Dist. France (ERDF)

Powerline Communications Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Powerline Communications Category Freq. Band Bit Rate Applications Ultra narrowband 0.3 – 3.0 kHz ~100 bps Automatic meter reading Outage detection Voltage monitoring Narrowband 3 – 500 kHz ~500 kbps Device-specific billing Smart energy management Broadband 1.8 – 250 MHz ~200 Mbps Home area networks Narrowband PLC systems Bidirectional communication over MV/LV lines between local utility and customers Industry standards: G3, PRIME International standards: G.hnem, IEEE P1901.2

Narrowband PLC Systems Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Narrowband PLC Systems Problem: Non-Gaussian impulsive noise is primary limitation to PLC communication performance yet traditional communication system design assumes noise is Gaussian Goal: Improve communication performance in impulsive noise (i.e. increase bit rate and/or reduce error rate) Approach: Statistical modeling of impulsive noise Solution: Receiver design to mitigate impulsive noise Parametric Nonparametric Listen to environment No training necessary Find model parameters Learn statistical model from communication signal structure Use model to mitigate noise Exploit sparsity to mitigate noise

Narrowband PLC Impulsive Noise Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Narrowband PLC Impulsive Noise Cyclostationary Noise Asynchronous Noise Example: rectified power supplies Example: uncoordinated interference Rx Receiver Dominant in outdoor PLC Increases with widespread deployment

Cyclostationary Noise Modeling Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Cyclostationary Noise Modeling Measurement data from UT/TI field trial Cyclostationary Gaussian Model [Katayama06] Proposed model uses three filters [Nassar12] Demux Period is one half of an AC cycle s[k] is zero-mean Gaussian noise Adopted by IEEE P1901.2 narrowband PLC standard

Asynchronous Noise Modeling Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Asynchronous Noise Modeling Dominant Interference Source Ex. Rural areas, industrial areas w/ heavy machinery Middleton Class A Distribution [Nassar11] Impulse rate l Impulse duration m Homogeneous PLC Network li = l, mi = m, g(di) = g0 Ex. Semi-urban areas, apartment complexes Middleton Class A Distribution [Nassar11] General PLC Network li, mi, g(di) = gi Ex. Dense urban and commercial settings Gaussian Mixture Model [Nassar11] Middleton Class A is a special case of the Gaussian Mixture Model.

Asynchronous Noise Sparse in time domain Learn statistical model Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Asynchronous Noise Sparse in time domain Learn statistical model Use sparse Bayesian learning (SBL) Exploit sparsity in time domain [Lin11] SNR gain of 6-10 dB Increases 2-3 bits per tone for same error rate - OR - Decreases bit error rate by 10-100x for same SNR time ~10dB ~6dB Transmission places 0-3 bits at each tone (frequency). At receiver, null tone carries 0 bits and only contains impulsive noise.

Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Our PLC Testbed Quantify application performance vs. complexity tradeoffs Extend our real-time DSL testbed (deployed in field) Integrate ideas from multiple narrowband PLC standards Provide suite of user-configurable algorithms and system settings Display statistics of communication performance 1x1 PLC testbed (completed) Adaptive signal processing algorithms Improved communication performance 2-3x on indoor power lines 2x2 PLC testbed (on-going) Use one phase, neutral and ground Goal: Improve communication performance by another 2x

Our PLC Testbed Hardware Software Task Summary | Background | PLC Noise Modeling and Mitigation | PLC Testbed Our PLC Testbed Hardware Software National Instruments (NI) controllers stream data NI cards generates/receives analog signals Texas Instruments (TI) front end couples to power line Real-time system runs transceiver algorithms Desktop PC running LabVIEW is used as an input and visualization tool to display important system parameters. 1x1 Testbed

Our Peer-Reviewed Publications Tutorial/Survey Article M. Nassar, J. Lin, Y. Mortazavi, A. Dabak, I. H. Kim and B. L. Evans, “Local Utility Powerline Communications in the 3-500 kHz Band: Channel Impairments, Noise, and Standards”, IEEE Signal Processing Magazine, Special Issue on Signal Processing Techniques for the Smart Grid, Sep. 2012. Conference Publications M. Nassar, A. Dabak, I. H. Kim, T. Pande and B. L. Evans, “Cyclostationary Noise Modeling In Narrowband Powerline Communication For Smart Grid Applications”, Proc. IEEE Int. Conf. on Acoustics, Speech, and Signal Proc., Mar. 2012, Kyoto, Japan. M. Nassar, K. Gulati, Y. Mortazavi, and B. L. Evans, “Statistical Modeling of Asynchronous Impulsive Noise in Powerline Communication Networks”, Proc. IEEE Int. Global Communications Conf., Dec. 2011, Houston, TX USA. J. Lin, M. Nassar and B. L. Evans, “Non-Parametric Impulsive Noise Mitigation in OFDM Systems Using Sparse Bayesian Learning”, Proc. IEEE Int. Global Communications Conf., Dec. 2011, Houston, TX USA.

Thank you for your attention… Questions?

Backup Slides

Cyclostationary Noise Asynchronous Impulsive Noise PLC Noise Scenarios Background Noise Cyclostationary Noise Asynchronous Impulsive Noise Spectrally shaped noise Decreases with frequency Superposition of lower-intensity sources Includes narrowband interference Cylostationary in time and frequency Synchronous and asynchronous to AC main frequency Comes from rectified and switched power supplies (synchronous), and electrical motors (asynchronous) Dominant in narrowband PLC Impulse duration from micro to millisecond Random inter-arrival time 50dB above background noise Caused by switching transients and uncoordinated interference Present in narrowband and broadband PLC time

Cyclostationary Noise Noise Sources Noise Trace

Uncoordinated Interference Results Homogeneous PLC Network General PLC Network