UNCLASSIFIED Cryptologic Quarterly

Data Communications Via Powerlines II (b) (3)-P.L. 86-36

The author is a member ofNSA Cohort 11 at bine, such as in nuclear- or coal-powered electric the Joint Military Intelligence College. Many of power plants, or a low-speed turbine, such as is the ideas presented in this paper were developed used in hydroelectric power plants). The power is as a class research paper at the Joint Military transferred to the transmission system via a volt­ Intelligence College. age step-up transformer.3 Typical voltages in this The views expressed in this paper are those of stage range from 138 kV to 500 kV or more. Bulk the author and do not reflect the official policy power is delivered from the generating plants via or position ofthe Department ofDefense or the this intercity transmission system (which can u.s. government. span several states) to the transmission substa­ tions where the power is transferred to a sub­ The hunger for increased bandwidth is driv­ transmission system whose voltages range from ing individuals, corporations, and organizations 38 kV to 138 kV; power transference is made via to seek new methods for delivering Internet serv­ a step-down transformer. The subtransmission ice to customers. Many of these methods are well system delivers the high voltage throughout a city known: radio-frequency (or wireless) communi­ or large region. Power is delivered to the con­ cations (such as the IEEE 802.11 Wireless LAN, sumers via the distribution system. Transference Bluetooth, and the HomeRF and SWAP from the subtransmission system to the distribu­ Protocols), infrared communications (IrDA), tion system is made within regions called distri­ fiber-optic channels, high-speed telephone con­ bution substations, likewise using step-down nections (such as DSL and ISDN or the more transformers. Output cables from the distribution modern Home Phoneline Networking Alliance substations are typically called feeders. (HomePNA) system).l One approach that is still receiving a cool reception in the United States is a In the United States, the distribution system highly discussed option in Europe and the rest of is subdivided into two components: the primary the world using the power grid as a delivery con­ distribution system (the voltages of which run duit for high-speed data communications. This from 4.6 kV to 12.47 kV)4 and the secondary dis­ paper provides a brief introduction to High­ tribution system (the voltages of which are the Speed Powerline Communications (HSPLC): the typical 120/240/208 voltages in houses and technologies, politi,al struggles, and future look. offices). Power from the primary distribution sys­ tem to the secondary distribution system is trans­ The Electric Power Grid Design ferred via the distribution transformers common­ ly seen on top of power poles or in large metal Before discussing HSPLC, it is informative to boxes near offices and apartment complexes. A outline the construction ofthe power delivery sys­ typical arrangement for suburban power connec­ tems in the United States and Europe. In the tions has four houses connected in a secondary United States, electric power is transferred from distribution system, being served by a single dis­ the power producer to the power user via a three­ tribution transformer. At best, a secondary distri­ stage delivery system. Electric power is generated bution system in the U.S. services only a few at a moderately high voltage (typically around apartments with a single transformer. 4.16 - 13.8 kilovolts (kV); 1 kV = 1000 volts)2 at the power plant (using either a high-speed tur-

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Europe and most ofthe rest ofthe world use a XlO,7 the granddaddy of powerline protocols, single layer distribution system. Output voltages uses amplitude modulation to send binary infor­ from the subtransmission substations range from mation from a controller/transmitter to XlO 200 to 300 volts, depending on the country. The modules that are plugged into a standard electri­ reasons for the differing philosophies are not cal outlet. The control pulses consist of 120 kHz important to this paper, but it is important to rec­ bursts with a 1ms envelope: the presence of a ognize that in the United States usually only a burst signals a logical "1" while the absence of a handful of consumers connected are in a single burst is a logical "0.,,8 A single bit is transmitted (secondary) distribution system while in the rest twice (for reliability)9 on each cycle of the 60 Hz of the world hundreds of consumers can be con­ AC power sine-wave; the bursts are synchronized nected in a single distribution system. As will be to within 200ms of the zero-voltage crossing seen later, these facts partially answer the ques­ point of the AC power sine-wave. As a result, its tion of why HSPLC is of great interest in Europe transmission rate is limited to 60 bits per second but of only mild interest in the U.S. (bps). Further, a complete X-lO command con­ sists oftwo packets, each containing two identical Low-speed Powerline Communications messages of 11 bits (voltage cycles); each packet is Protocols separated by a 3-cycle gaplO (again, redundancy for reliability). The result is that a single X-lO Using the electric powerline to send informa­ commandtakes approximately 47 cycles ofthe 60 tion is not a new idea. Sweden has used its elec­ Hz signal or 0.8 seconds to send. tric power grid for telephone communications for many years. Further, electric power lines have The developers of the CEBus standard (EIA­ been used throughout the world for low-frequen­ 600) state that they use spread-spectrum tech­ cy communications by the electric power indus­ nology to transmit data.ll However, unlike tradi­ try, for baby monitors, or simple control func­ tional spread-spectrum techniques such as fre­ tions, using protocols such as XlO@ Home quency-hopping or direct-sequence spreading, Automation, Intellon CEBus@, Echelon the spread-spectrum of CEBus sweeps the signal LONWorks@, or Intelogis [email protected] These frequency from 100 Hz to 400 Hz for each bit. proprietary protocols are low speed and are used According to the developers, this overcomes some solely for controlling consumer systems, such as of the inherent noise problems associated with lights, appliances or simple electronics. In addi­ higher speed powerline communications. Like tion to these consumer-oriented protocols, the XlO, CEBus has two fundamental components: a power industry has a separate protocol for using transceiver and a microcontroller. Unlike XlO, powerlines to communicate system control CEBus is not restricted to powerline communica­ (SCADA) data. In the past, signals used by the tions but can use any communication media, electric utilities for controlling signal powerline including RF. 12 At its higher level, CEBus uses communication have been analog. Data are trans­ its own Common Application Language (CAL) to mitted using either amplitude modulation (either ensure that CEBus compliant systems made by double-sideband or single-sideband) or frequen­ different manufacturers can exchange commands cy-shift (ON-OFF) keying on carrier frequencies and status requests.13 CAL creates device "con­ from 30 kHz to 500 kHz in the U.S. and from 10 texts" and object classes to communicate a kHz to 490 kHz in Canada.6 Because the power given command to the appropriate device. 14 The industry worldwide is changing its protocols for CEBus protocol is similar to Ethernet in that all SCADA communications, this report does not (a) it is peer-to-peer and (b) it uses a Carrier examine the power utility protocols. Sense Multiple Access/Collision Detection and Resolution (CSMA/CDCR) protocol to avoid data

Page 54 UNCLASSIFIED UNCLASSIFIED Cryptologic Quarterly collisions.15 This protocol requires a network client/server operation) or the CEBus Generic node to wait until the line is clear so that there Common Application Language (CAL, for peer­ will be no simultaneous transmission on the line. to-peer operation); at the Network, Transport, Data are transmitted at the rate of approximately and Data Link Layers, PLUG-IN defines the 10 kilobits per second (kbps). Standard EIA 709.2 Power Line Exchange (PLX) Protocol while at the defines the specifications to use either CEBus for Physical Layer PLUG-IN uses the Digital Power sending data over two- and three-phase electrical Line (DPL) Protocol. Using DPL, PLUG-IN powerlines. The standard restricts the powerline boasts data transmission rates of up to 350 kbps channel to a spectral bandwidth from 125 kHz to using a single channel frequency. PLUG-IN uses 140 kHz and specifies data communication rates Frequency-Shift-Keying (FSK) to encode the data of 5.65 kbps while providing a narrow-band onto the signal carrier. A proposed version of power line signaling technology that meets North PLUG-IN DPL (for Digital Power Line) is to use American and European regulations.16 multiple signal channels to produce speeds of over 1 Mbps. Bit error rates for DPL are in the LONWorks17 (ANSI/EIA 701.9-A-1999) is range of 10-9 with 80 dB of dynamic range. The similar to CEBus: it works as either a peer-to-peer FSK scheme encodes the digital data onto the or a master-slave data communication system; it power line by using two or more separate fre­ uses spread spectrum technology to transmit quencies that are in a fairly narrow frequency data; and it uses a CSMA technique for data colli­ band. Like the other low-speed powerline com­ sion avoidance. Additionally, LONWorks also munications protocols, PLUG-IN is intended for supports many communication media including control system communication signals. However, twisted pair, power line, fiber-optics, coaxial the success of DPL has led other companies to cable, radio frequency, and infrared!8 Unlike attempt to modify it for carrying high-speed data CEBus, LONWorks supports higher data rates: communications over powerlines. from 610 bps up to 1.25 Mbps19 and is a propri­ etary protocol, requiring a license for operation. High-speed Powerline Communications However, if used for data transmission over Protocols powerlines, LONWorks is restricted by EIA 709.2, just like CEBus. The LONWorks standard There are many difficulties in using power­ implements a control system communication lines for High Speed Powerline Communications network using an open communications protocol, (HSPLC), including the wide variation in the line LONTalk, and LONWorks Network Services impedance as a function of frequency, the high (LNS), in addition to a proprietary MAC protocol attenuation and interference problems, and the to provide the peer-to-peer networking layer. A signal reflections caused by signal mismatches.21 key feature of LONworks is the LNS, which pro­ Each developer of HSPLC products has attempt­ vides an object-oriented method to connect net­ ed to solve these difficulties by proposing differ­ worked control devices. LNS clients can run on ent protocols. While many companies and organ­ any platform (PC, MAC, UNIX, embedded, etc.). izations have been (and still are) pushing their LNS Server supports both LONTALK and TCP/IP concept, only four primary protocols are actively protocols at the transport layer. competing to become THE protocol for HSPLC. These are Intellon's PowerPacket™ protocol, PLUG-IN20 is based on the Open System Intelogis' Plug-In PLX™, Digital PowerlineM Interconnection (OS!) model and defines several (DPL), and Adaptive Networks' AN1000 Power protocols: at the Application Layer, PLUG-IN Line Communication system. uses either the proprietary Intelogis Common Application Layer (iCAL) Protocol (for

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The HomePlug (Powerline) Alliance consists and modulate each carrier by a separate low-rate of over forty members who are major manufac­ data stream. However, where FDMA allocates turers of computers and data communication each subchannel (which are typically 10 kHz to 30 equipment, including 3Com, CISCO, Compaq, kHz wide) to separate users, OFDM uses all the Intel, Motorola, Panasonic, Radio Shack and subchannels (OFDM typically has 100-1000 sub­ Texas Instruments. On June 5, 2000, channels, each around 1 kHz wide)26 to broadcast PowerPacket was selected by the HomePlug a single message, thus allowing more data to be Alliance to become the basis for an industrial transmitted faster with a lower symbol rate than 22 specification in home powerline networking. in FDMA. Figure 1 is a graph of a typical As a result, most of the manufacturers who were OFDM/FDMA spectrum. Coded Orthogonal developing the other protocols (with the excep­ Frequency Division Multiplexing (COFDM) is the tion ofAdaptive Networks) are moving away from same as OFDM except that forward error correc­ their original developments and turning their tion is applied to the signal before transmission. attention to creating products that will conform to the new HomePlug standard. One problem encountered with power line communications is aliasing (distortion of a signal due to the interference of the signals from adja­ cent channels). As data rates increase and chan­ nel bandwidths narrow, aliasing increases. In order to prevent aliasing, guard frequency bands are included in each subchannel. This means that a portion of the spectrum allocated to each sub­ channel is a "dead zone" of no signal. The guard bands in FDMA are large (typically up to 50 per­ cent of the total spectrum),27 whereas in OFDM the guard bands are much smaller resulting in the spacing between channels being closer in OFDM than in FDMA. By setting all the subcarriers orthogonal to each (hence, the definition of Orthogonal Frequency Division Multiplexing), interference is reduced between the closely Fig. 1. Time-Ftequency Spectt

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Another of the problems with HSPLC is that Because oftheir low symbol rates, ODFM sig­ ofmultipath reflections. Figure 2 below indicates nals are highly resistant to multipath interfer­ the concept of multipath reflections in the case of ence.28 Additionally, a time domain guard period, radio communications. shown in figure 3, is added to reduce the possibil­ ity of interference due to the symbol spreading Multipath interference, also called "ghosting," caused by the multiple paths.29 results when a signal travels from a transmitter to a receiver via multiple possible signal paths. Since Theoretically, the OFDM protocol should be the time required for a signal to travel a finite dis­ able to operate at up to 100 Mbps, although most tance varies directly with the distance, a signal devices operate at around 14 Mbps.30 Since the that travels over multiple paths will result in a RF characteristics of a powerline vary as a func­ multitude of signals being presented at the tion of frequency, using different modulations receiver, each received signal slightly time-shifted would allow the channel efficiency to be opti­ with respect to each other (i.e., having phase mized to its maximum potential.31 Because the shifts with respect to each other). These multiple subchannel carriers are orthogonal to each other, paths can be created by reflections (in a power­ each subcarrier in OFDM can be modulated with line, reflections are the result of impedance mis­ a separate modulation scheme such as any com­ matches between the transmission line and the bination of coherent or differential, phase or loads attached to the line) or diffractions around amplitude modulation schemes, including BPSK, obstacles (in a powerline, diffractions are caused QPSK, 8PSK, 16QAM, 64QAM or others. by imperfections, such as "kinks" or cracks in the Normally, this is not done, but the same modula­ transmission line). For powerline communica­ tion scheme is used on all subchannels for the tions, multipath distortion results in digital inter­ sake of economy of design. The choice of the symbol interference. Like aliasing, multipath modulation scheme depends on how much noise interference increases with frequency. is in the channel.32

While the HomePlug Alliance has chosen OFDM signal with half zero guard period ODFM to be the standard powerline communica­ tion protocol, not everyone agrees that it is the best. Michael Propp, president of rival Adaptive Networks Inc., claims that the HomePlug proto­ col "enables a PC-centric, point-to-point unicast­ ing network" and that such a network is "not a usable home network.,,33 A rival consortium, the Consumer ElectroniCs Association (CEA) R7.3 Committee, argues that, for it to be applicable for home use, a powerline network must be able to support a large number of nodes and "simultane­ ous entertainment activities such as streaming audio and video, plus provisions for multicasting 2.4 2.6 2.8 3 3.2 3.4 3.6 and broadcasting," something PowerPacket does Samples x 104 not provide.34 However, an interesting feature of the 14 Mbps PowerPacket chips currently being Fig. 3. OFDM Sig041 With GU4rq Pericxl produced by Intellon (INT5130) is that they come From L4wrey, Ch4pter 1. equipped with real-time 56-bit DES encryption of

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-1.. _ • Cryptologic Quarterly UNCLASSIFIED data packets,35 a feature that has been identified The other major HSPLC technologies, Plug-In as a major need in powerline communications PLX and Digital Powerline, are similar in techni­ but has not been stressed in design circles. cal content and were discussed earlier in the low­ frequency protocols. They both operate around 1­ Propp argues that home networks need a 2 Mbps and use frequency-shift key (FSK) tech­ wideband spread-spectrum transmission and niques. adaptive equalization to ensure that some portion of the transmitted spectrum is received without Regulatory Issues ofPowerline distortion due to "the multiple peaks and valleys Communications of the power line transfer function."36 As shown in figure 4,37 the transmission line attenuation There is a spirited debate raging in Europe (the dark line) is not constant but varies with fre­ over HSPLC (the topic is hot in Europe, since the quency. A narrowband spread-spectrum signal technology there is capable ofbeing cost effective. In the U.S., the market has yet to develop so the Attenuation issue is not as hotly pursued.) The debate centers mostly on the electromagnetic compatibility/ electromagnetic interference (EMC/EMI) issues associated with HSPLC. Key players in this arena are the International Powerline Communications Forum (IPCF), the European Telecommunica­ tions Standards Institute (ETSI), the International Telecommunication Union (ITU), the European Radiocommunications Office (ERa), a subcommittee of the European 60 kHz <160kHz Conference of Postal and Telecommunications Frequency Administrations (CEPT) (ERa coordinates Fig. 4. Powetllne Attenuation and Spread Spechum. radiofrequency spectrum allocations in From Adaptive Netwotks. Europe),38 the European Committee for Electrotechnical Standardization (CENELEC),39 (shown with the light colored line) may not pass and the ComiM Internationale Special des some frequencies while a wideband spread-spec­ Perturbations Radioelectrotechnique (CISPR), a trum signal (the medium colored line) will allow committee of the International Electrotechnical some portion ofthe signal to pass. However, since Commission (IEC) dealing with the technical the attenuation vanes with frequency (as well as issues ofEMC and other related matters. The IEC time and distance between the source and the itself is the worldwide standards-setting institu­ receiver), the receiver must adapt to the changing tion concerned with all aspects of electrical tech­ conditions. nology (CENELEC is the European member of the IEC, just like the ISO is the U.S. member of Propp's own corporation, Adaptive Networks, the IEC). Inc., just happens to manufacture a product that provides these features: the AN1000 Power line In a nutshell, the problem is that HSPLC radi­ Communication system. Adaptive Network's pro­ ates electromagnetic energy off the power trans­ tocol, which is being considered by the CEA R7.3 mission lines. Depending on the data rate, signal Committee for its specification, pushes wide­ frequencies of HSPLC can vary from 100 kHz to band spread spectrum and adaptive control ofthe 30 MHz, a band offrequencies that is highly used receiver. for mobile, marine and aeronautical distress and

Pag.58 UNCLASSIFIED UNCLASSIFIED Cryptologic Quarterly calling, for time signals used by radio the UDPITCPlIP suite. New products and new astronomers, by airports for civil defense com­ concepts are constantly being added. munications - in short, a wide variety of critical communications. Currently, spectral usage in this That said, there are many critics of the entire area is set by ERa and the radiation limits are concept of powerline data transmission, particu­ established by CISpR,40 The IPCF has been lob­ larly high-speed powerline communications bying the IEC to change the standards for radia­ (HSPLC). Some ofthe problems and criticisms to tion in the frequency bands. Needless to say, the be resolved are as follows: massive amount of coordination between the ETSI/ITU, CISPR/IEC, ERO/CEPT and CEN­ HSPLC is unfeasible and inefficientfor data ELEC is slowing the regulatory aspects of HSPLC transmission. This argument is losing ground as adoption. Additionally, there is massive resist­ practical devices capable of operating at tens of ance by the current users of the proposed fre­ megabits per second are appearing. Tests have quency band (coming from civil defense organi­ shown that the new devices have overcome some zations, military, scientific (astronomy) organiza­ of the limitations inherent in older HSPLC tions - everyone who has a stake in the outcome). designs and that high data rates with low bit­ However, the current state of HSPLC regulation error rates are possible. is a declaration by the IEC that there WILL be a revision ofthe frequency band and EMC limits in HSPLC is impractical, especially in the order to accommodate HSPLC. 41 ETSI and CEN­ United States, due to signal blockage by the ELEC are jointly developing a new standard to power transformers. As discussed earlier, only a accommodate everyone, but there will be much few consumers are linked together in the U.S. by effort before everyone is satisfied.42 the power distribution system while many con­ sumers are linked together by the distribution Summary system in the rest of the world. These power transformers in the U.S. distribution system thus The growing digital revolution is creating an inhibit potential Internet communication. ever-increasing demand for bandwidth. Many Supporters have countered by noting two areas products and services are being introduced to ful­ HSPLC can serve: as a local area network within fill this demand, one ofwhich is the use of power­ a home, building, or small office (where being lines to transport data, whether by low-speed or able to plug-and-play a device using a standard high-speed data transmission. Many companies power plug is a great attraction for the consumer) are working to create what they consider to be the and as a bulk carrier between regions (using the ideal approach to using powerlines for data trans­ transmission grid of the power industry). mission. In the low~speedpowerline communica­ Further, the supporters have argued that contem­ tions arena, used primarily for simple functions porary systems are just as impractical: the cost of such as simple system control and low-frequency laying optical fiber to the door of each consumer communications (e.g., baby monitors), propri­ makes that option unlikely; that DSL doesn't etary protocols still dominate. These systems are reach every home, particularly in the U.S.; that well established, and the only new innovations telephone modems rely on multiplexing in order are to add more products to the line. On the other to extend access to more persons (i.e., technology hand, high-speed powerline communications is used in telecommunications today can be easily just entering the respectability phase of product and cheaply adapted to HSPLC at the distribution design. The signaling characteristics ofthe differ­ transformer to multiplex the users onto the rest of ing protocols are proprietary, but the higher-level the network); and that all telecommunication communications protocols are proposed to be of

UNCLASSIFIED Page 59 Cryptologic Quarterly UNCLASSIFIED options suffer degradation as the number ofusers 5. Feng. increases. 6. IEEE Guide for Power-Line Carrier Applications, Draft #6 (New York: Institute of The biggest headache is the regulatory limits Electrical and Electronics Engineers, Inc., July 2000), imposed by EMC/EMI considerations. There are 22. many opponents to HSPLC as a result of this 7. Feng. issue. However, regulations change, and the more 8. Amitava Dutta-Roy, "Networks for Homes," that industry desires the introduction of HSPLC, IEEE Spectrum 36, No. 12, December 1999, 30. Cited the more likely the existing regulations will be hereafter as Dutta-Roy. modified. 9. Feng. 10. Feng. Security issues have been little addressed. 11. About CEBus Standard, There is a growing recognition that HSPLC has a http://www.exp-math.uni-essen.de/-vinck/plc/ serious security vulnerability, particularly in cebus_main.htm (24. July 2001). Europe, due to the interconnectedness of the net­ 12. Feng. work and the open protocols (UDPITCPlIP) 13. Feng. being proposed. Industry is starting to address 14. Dutta-Roy, 30. these issues, but caveat emptor. 15. Feng. 16. "EIA-709.2 Control Network Power Line (PL) Powerline carrier communications is here to Channel Specification," stay. It may be limited to a local area network http://www.exp-math.uni-essen.de/-vinck/plc/ eia­ within the home or office, or it may become 709.htm (24 July 2001). Cited hereafter as EIA-709.2. another medium like telephone modem commu­ 17. Feng. nications, but it will be used in the future. The 18. EIA-709.2. only real obstacle to its full development is the 19. "Existing Powerline Communications lack of a standard around which the entire indus­ Standards," Powerline Communications, try can rally. The future holds the answer. http://www.exp-math.uni-essen.dej-vinck/plc/ cwt-faq.htm (24 July 2001). Notes 20. Feng. 1. Xinhua Feng, 14 November 1999, Home 21. Dutta-Roy, 30. Networking, http://www.exp-math.uni-essen.de/ 22. "HomePlug Select Intellon's PowerPacket -vinckjplcjhomenetworking.htm (24 July 2001). Technology," 5 June 2000, Powerline World - News Cited hereafter as Feng. Headlines, http://www.powerlineworld.com (24 April 2. Theodore R. Bosela, Introduction to Electrical 200l). Power System Technology (Upper Saddle River, NJ: 23. HomePlug 1.0, www.homeplug.org (24 April Prentice Hall, 1997), 81. Cited hereafter as Bosela. 2001). 3. A transformer is essentially a large block of iron 24. Margaret Quan, "Sparks Fly as Power Line whose purpose is to "transform" the voltages and cur­ Networks Surge Ahead," EE Times, 9 June 2000, 204. rents from one system to another. A "Step-up" trans­ 25. Eric Lawrey, Chapter 1 - Introduction, 24 former means that the output voltages of the trans­ October 2000, http://www.eng.jcu.edu.au/eric/ the­ former are higher than the input voltages. A "Step­ sis/MultiuserOFDM/multiuserOFDM.html (31 July down" transformer means that the output voltages of 2001). Cited hereafter as Lawrey, Chapter 1. the transformer are lower than the input voltages. 26. Lawrey, Chapter 1. Transformers have great impact on data communica­ 27. Lawrey, Chapter 1. tions. 28. Eric LaWTey, "Multiuser OFDM Paper," 4. Bosela, 89. http://www.eng.jcu.edu.au/eric/thesis/

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MultiuserOFDM/multiuserOFDM.htm (31 July Adaptive Networks, The Powerline As a 2001). Cited hereafter as LaWTey, "Multiuser OFDM." Reliable High-Speed Communication Medium. 29. LaWTey, Chapter 1. http://www.adaptivenetworks.com/prsprint.pdf 30. Margaret Quan, "Intellon Rolls HomePlug (24 July 2001). Silicon As Field Trials Conclude," EE Times, 8 May 2001.http://www.eetimes.com/story/ Bosela, Theodore R. Introduction to OEG20010507S0047 (24 July 2001). Cited hereafter Electrical Power System Technology. Upper as Quan, "Field Trials." Saddle River, NJ: Prentice Hall, 1997. 31. LaWTey, "Multiuser OFDM." 32. LaWTey, "Multiuser OFDM." Dutta-Roy, Amitava. "Networks for Homes." 33. Margaret Quan, "HomePlug Completes IEEE Spectrum 36, No. 12, December 1999,26 ­ Powerline Network Spec," EE Times, 28 June 2001, 33. http://www.eetimes.com/story/OEG20010627S0049 (31 July 2001). Cited hereafter as Quan, "Powerline "EIA-709.2 Control Network Power Line (PL) Spec." Channel Specification." 34. Quan, "Powerline Spec." http://www.exp-math.uni-essen.de/-vinck/ 35. Quan, "Field Trials." plc/eia-709.htm (24 July 2001). 36. Michael Propp, "Power Line Protocols Back Multimedia Use," EETimes, October 11,1999, "Existing Powerline Communications http://content.techweb.com/se/ Standards." Powerline Communications. directlink.cgi?EETI9991011S0066 (24 July 2001). http://www.exp-math.uni-essen.de/-vinck/plc/ 37. Adaptive Networks, The Powerline As a cwt-faq.htm (24 July 2001). Reliable High-Speed Communication Medium, http://www.adaptivenetworks.com/prsprint.pdf (24 Feng, Xinhua. 14 November 1999. Home July 2001). Cited hereafter as Adaptive Networks. Networking. 38. http://www.cept.org/ (7 August 2001). http://www.exp-math.uni-essen.de/-vinck/ 39. "Info - About CENELEC", plc/homenetworking.htm (24 July 2001). http://www.cenelec.org/Info/about.htm (7 August 2001). Greimel, Hans. "Companies Unveil New 40. http://www.emclab.umr.edu/cispr.html (7 Technology That Turns Electric Sockets into August 2001). Phone Jacks." 22 March 2001. TBO.com's 41. John Newbury, IEEE representative to the Weather Center. ITU, in a public address at the 2001 IEEE Summer http://ap.tbo.com/ap/breaking/ Power Meeting, Vancou'(er, BC, 15 - 19 July 2001. MGANH7T2NKC.html (23 March 2001). 42. John Newbury,' "Regulatory Requirements for Power Communications Systems Operating in the HomePlug 1.0. www.homeplug.org (24 Apr! High Frequency Band," Proceedings of the 2001). 5th International Symposium on Power-Line Communications and Its Applications (ISPLC), "HomePlug Select Intellon's PowerPacket Malmo, Sweden, 4-6 April 2001, 305-310. Technology." 5 June 2000. Power/ine World ­ News Headlines. References http://www.powerlineworld.com (24 April 2001). About CEBus Standard. http://www.exp-math.uni-essen.de/ http://www.cept.org/ (7 August 2001). -vinck/plc/cebus_main.htm (24 July 2001).

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http://www.emclab.umr.edu/cispr.html (7 Propp, Michael. "Power Line Protocols Back August 2001). Multimedia Use." EETimes.com, October 11, 1999. IEEE Guide for Power-Line Carrier http://content.techweb.com/se/ Applications, Draft #6 (New York: Institute of directlink.cgi?EET19991011S0066 (24 July Electrical and Electronics Engineers, Inc., July 2001). 2000). Quan, Margaret. "Intellon Rolls HomePlug "Info - About CENELEC." Silicon As Field Trials Conclude." 8 May 2001. http://www.cenelec.org/Info/about.htm EETimes.com. http://www.eetimes.com/story/ (7 August 2001). OEG20010507S0047 (24 July 2001).

Lawrey, Eric. "Chapter 1 - Introduction." 24 Quan, Margaret. "Sparks Fly as Power Line October 2000. Networks Surge Ahead." Electronic Engineering http://www.eng.jcu.edu.au/eric/thesis/ Times, 9 June 2000: 204-205. MultiuserOFDM/multiuserOFDM.html (31 July 2001).

Lawrey, Eric. "Multiuser OFDM Paper." http://www.eng.jcu.edu.au/eric/thesis/ MultiuserOFDM/multiuserOFDM.html (31 July 2001).

Newbury, John. IEEE representative to the lTD, in a public address at the 2001 IEEE Summer Power Meeting, Vancouver, BC, 15 - 19 July 2001.

Newbury, John. "Regulatory Requirements for Power Communications Systems Operating in the High Frequency Band." Proceedings of the 5th International Symposium on Power-Line Communications and Its Applications (ISPLC), Malmo, Sweden, 4 - 6 April 2001, 305-310.

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86-36 ...... /i I1\\ {b{ (3)-P.L.

~ lisase~i~r Engineer/TechnologyVulnerabilityAnalyst in C311, a position he has held since 10 August 1998~ (U//FOUO) He was an NSA Cooperative Educationenlployee from 1974 to 1977, and he has worked as a/rocketplulJ}.m~e~~I!:':::iii-iiii~ ----, i diagnostics engineer for Sverdrup Technologies,/198 i 1982; as a sonar/underwater magnetics/engine.er f()r the Naval Coastal Systems Center, 1983; as a /nlunitions J design engineer for Sandia National laboratories, 1984- I 1987; as a research engineer for the Georgia Tech Research Institute, 1988-1990; and as an assistant professor of engineering at John BrOwn University, 1995-1998. (U//FOUO~ // f

(U//FOUO) Js a member of the Institute of Electrical and Electronics Enaineers and the American Society of Enaineerina Educators. II

(Uh'!"'OUO}1 !was certified as a Cryptologic Engineer by NSA in 1977. He is an NSA adjunct faculty member.

/(b) (6)

I I

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