High-Speed Power-Line Communication and Its Application to a

IEICE TRANS. FUNDAMENTALS, VOL.E89–A, NO.11 NOVEMBER 2006

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INVITED PAPER

Special Section on Wide Band Systems

High-Speed Power-Line Communication and Its Application to a Localization System∗ Shinji TSUZUKI†a) , Member

SUMMARY This paper overviews the high-speed power-line communication (PLC) technology, and the related standardization and regulatory activities are described. PLC modems of 200 Mbps class become a practical use stage in the West, and the standardization activity is active now. The discussion for deregulation is being continued in also Japan, and regulation values have been proposed. Another topic in this paper is a sensor network application of PLC, which is an indoor fine-grained localization system by acoustic Direct-Sequence Code Division Multiplexed (DS-CDM) signals. The obtained average accuracy of the localization in a 4 m2 plane was 1 cm if there was no obstacle. To realize the localization system, some novel ideas, such as PLC speakers, a synchronization method based on the zerocrossing timing of the mains frequency, and integrated wired/wireless PLC, are introduced. key words: power-line communication (PLC), broadband over power-line (BPL), home network, standardization, sensor network, localization

1.

Introduction

The power-line communication (PLC) for home networks is a system which distributes communication data by injecting signals between residential power-line wires. The PLC is a rational networking solution since it realizes the integrated power and information delivery (IPID) [2] by using existing power-lines. The channel characteristics of the frequency band of 10 k to 450 kHz which the conventional PLC systems have been allowed to use is quite inadequate because the characteristics are seriously affected by the noise and impedance of household-electric-appliances connected to the lines. Then it was general recognition that the possible data rate of PLC was low (about 9,600 bps) so that the possible applications were limited, e.g. the ON/OFF control of lights [3]. Recently, high-speed PLC modems (max. 200 Mbps) based on the Orthogonal Frequency Division Multiplexing (OFDM) technology using the High-Frequency band (HF band; 2 M to 30 MHz) have been put in practical use in Europe and America, e.g. Universal Powerline Association (UPA) and HomePlug AV standard based products (these details will be mentioned later). Note that the highspeed PLC is also referred to as Broadband over PowerLines (BPL). However, the interference with the existing radio-communication services or radio astronomy stations Manuscript received June 5, 2006. Manuscript revised June 20, 2006. Final manuscript received July 13, 2006. † The author is with the Graduate School of Science and Engineering, Ehime University, Matsuyama-shi, 790-8577 Japan. ∗ This paper is a revised version of [1]. a) E-mail: [email protected] DOI: 10.1093/ietfec/e89–a.11.3006

Table 1 Company (Country) DS2 (Spain) Intellon (USA) Yitran (Israel) Matsushita (Japan)

HF-band PLC chips.

Data rate (Mbps)

Modulation

Frequency [Hz]

Note

200

OFDM

2 M – 30 M

(1)

150

OFDM

2 M – 28 M

(2)

2.5

SS

4 M – 20 M

(3)

170

Wavelet OFDM

2 M – 30 M

(4)

Note(1) DSS900X family. http://www.sei.co.jp/tr/t technical pdf/sei1 0458.pdf. Baseline technology for UPA and Opera standards. Note(2) Baseline technology for the HomePlug standards. Note(3) Microsoft SCP (Simple Control Protocol) based products are also supplied (http://www.yitran.com/it800tool. htm). Joint venture companies exist in Japan (http://www.yitran. com/profile.htm). Note(4) Referred to as HD-PLC [11].

is concerned since the PLC modems using the HF band (abbreviated to HF-band PLC) cause the unwanted radiation from the power-line cables. Therefore, related organizations, such as CISPR (The International Special Committee on Radio Interference), are doing the work which fixes the permissible limits of transmission power from the modems [4]–[6]. The rest of this paper is organized as follows. The overview of the high-speed PLC technology and the related standardization and regulatory activities are described from Sect. 2 to Sect. 4 [7]–[10]. In Sect. 5, a sensor network application in consideration of the feature of PLC is introduced. The conclusion is written in Sect. 6. 2.

HF-Band PLC

The typical LSI chips for the HF-band PLC are shown in Table 1. DS2∗∗ is a company which has been successful by PLC chips for Internet access services mainly in the European market. The technology of Intellon∗∗∗ has been adopted as HomePlug standards shown in Table 2. The specification of version 1.0 (referred to as HomePlug 1.0 or HP-1.0) was published in June, 2001∗∗∗∗ . The HomePlug certified products are put on the market from 12 companies now∗∗∗∗∗ , ∗∗

http://www.ds2.es/ http://www.intellon.com/ ∗∗∗∗ http://www.homeplug.org/en/news/HomePlug Electronic Pre ss Kit.pdf ∗∗∗∗∗ http://www.homeplug.com/en/products/products.asp ∗∗∗

c 2006 The Institute of Electronics, Information and Communication Engineers Copyright

TSUZUKI: HIGH-SPEED POWER-LINE COMMUNICATION AND ITS APPLICATION TO A LOCALIZATION SYSTEM

3007 Table 2 Version

HP-1.0 [12]

Raw data rate

20 Mbps(1)

Data rate

13.75 Mbps(2)

HomePlug standards. HP-1.0 with Turbo

HP-AV [13] 200 Mbps

85 Mbps

150 Mbps

Frequen4.3 M – 20.9 MHz 2 M–28 MHz cy range ModulaQAM 256/64/ windowed OFDM(3) tion 16 are added OFDM Security 56 bit DES 128-bit AES Access CSMA/CA with prioritization both TDMA protocol and ARQ and CSMA/CA (1) DQPSK, rate 3/4 FEC coding, and 84 carriers. Symbol duration: 8.4 µs. Carrier interval: 156 kHz. (2) DQPSK, rate 3/4 FEC. (3) DQPSK, DBPSK, ROBO

and their prices are equivalent to those of wireless LAN, so that the price of a cheap PLC modem is about 35 dollars. According to the field test results by HomePlug Powerline Alliance (HPA), the throughput (for the TCP protocol) of 5 Mbps was attained by 73% of wall sockets in a house in the U.S., and 1.5 Mbps was done by 97% of wall sockets† . The specification for HomePlug AV (HP-AV) was finalized in August, 2005†† . Although the HP-1.0 standard had a mechanism of priority transmission of four levels, the HP-AV standard was improved it so that it became more suitable for streaming with high speed and high (HDTV class) quality. All HP-AV and HP-1.0 devices can exist together on the same power line. Moreover, HPA chose the HP-AV specification as the basis for its upcoming the “HomePlug access BPL” standard shown in Table 3(a). 2.1 MAC Protocol of HomePlug AV The protocol outline about Quality of Service (QoS) of HPAV is described below. It is characterized by the usage of the mains frequency for the time-slot synchronization of Time Division Multiple Access (TDMA). The medium access (MAC) sub-layer of the data link layer of HP-AV provides both contention and connectionoriented Contention Free (CF) services through the respective regions in Beacon Period as shown in Fig. 1. The former service is based on Carrier Sense Multiple Access (CSMA) technology to support best-effort applications with four priority levels. The later CF service is based on periodic timeslot allocation with the adequate duration which satisfies the QoS requirements (e.g. guaranteed bandwidth, latency and jitter requirements) for the AV streaming [13], [14]. A central manager called Central Coordinator (CCo) establishes a Beacon Period and its schedule which accommodates both the CF sessions and the time allotted for CSMA-based traffic. As shown in Fig. 1, the Beacon Period is divided into 3 regions of Beacon Region, CSMA Region, and Contention-Free Region. Since the Beacon Period is synchronized to the AC line cycle, a channel adaptation to

Fig. 1

Beacon period of HomePlug AV.

the AC-line-cycle synchronized noise and the periodic region allocations become possible. The CF region consists of non-persistent and persistent allocations. A transmitting station using a persistent allocation session can continue to transmit its data even if it has missed several beacons which advertise the schedule. The non-persistent allocations are used to provide short term communications. If these allocations are not used, they may be used for the CSMA traffic.

3.

BPL Standards

Several competing BPL standards are evolving as shown in Table 3. Although it is unclear which standard will come out ahead, the HomePlug standard and the DS2-based standard (Open PLC European Research Alliance (OPERA) and UPA) whose products have already circulated to the U.S. and Europe respectively are predominant. Therefore, making a standard for coexistence when these standards are intermingled will become the main subject for the discussion. While the standards of the U.S. and Europe are competing, the action of Japan (or CEPCA which mostly consists of Japanese household-electric-appliance makers) also attracts attention since it is expected that a lot of appliances will be equipped with the PLC modems. Standards efforts by industry alliances are as follows. HPA (HomePlug Powerline Alliance): Intellon Corporation (U.S.A.) is a major contributor to the baseline technology for the HomePlug standards. It was announced that more than 3 million power-line networking devices based on the HP-1.0 standard had been sold since 2001††† . UPA (Universal Powerline Association): UPA specified the Digital Home Standard (DHS) for AV streaming using the chip-sets of DS2 (Spain) at March 2006. † http://www.homeplug.org/en/docs/HomePlug Field Test Re sults.pdf †† http://www.homeplug.org/en/news/press081905.asp ††† http://www.intellon.com/pdfs/article mercurynews 2005101 0.pdf


3008 Table 3 Application

Standards efforts.

(a) By industry alliances. HPA UPA

In-home HP† -1.0, HP† -AV DHS† Access HP† Access BPL (OPERA) Control HP-C&C‡ – HP† : HomePlug HP-C&C‡ : HomePlug Command & Control DHS† : Digital Home Standard (b) By international bodies. Function IEEE OPERA ETSI MAC/PHY – P1901 † Coexistence TS 101-867 EMC P1775 – – Hardware P1675 TS 101-896 † : for broadband Internet access ‡ : CISPR/I/26/DC, CISPR/I/44/CD, and [4]

CEPCA (HD-PLC) – (NILLC)

CISPR – ‡ –

The DHS is designed to work harmoniously with broadband access power-line equipment based on the OPERA standard. CEPCA (Consumer Electronics Powerline Communications Alliance): Although the two above-mentioned alliances aim to become the so-called de facto standard, the purpose of CEPCA is to create and standardize technical specifications that enable those different PLC systems to coexist from the consumer electronics industry’s point of view. Main Japanese consumerelectronics makers (Panasonic, Hitachi, Mitsubishi, Pioneer, Toshiba, Sony, and Yamaha) and other eight companies have participated. The chip-set named HD-PLC shown in Tables 1 and 3 is a product of Matsushita Electric Industrial Co., Ltd., which is one of the founding companies. NILLC (Non Interference Legacy Line Communication) proposed by RENESAS Corp. is a technology for homecontrol and sensor networks† . The specification for coexistence based on FDMA (Frequency Division Multiple Access) was released in April, 2006 [15]. Standards efforts by international bodies are as follows. IEEE: The scope of IEEE P1901 is the standard of the physical layer (PHY) and the MAC layer for high speed (> 100 Mbps at the PHY layer) BPL operating on frequencies below 100 MHz for access and in building LANs. The issues are “mechanisms for coexistence and interoperability between different BPL devices,” and “security and privacy.” Selection process will be started from June, 2006†† . The scope of P1775 is the electromagnetic compatibility (EMC) criterion, and the consensus of test and measurement procedures for BPL equipment and installations. The standard will refer existing national and international standards for BPL equipment and installations. It will not include the specific emission limits, which are subject to national regulations††† . IEEE P1675 will give electric utilities a compre-

hensive standard for installing the required hardware on distribution lines, both underground and overhead, which provide the infrastructure for BPL systems. It also will include installation requirements for the protection of those who work on BPL equipment and to ensure such systems do not place the public at risk. The standard is targeted for completion in mid 2006†††† . OPERA (Open PLC European Research Alliance) : OPERA is an industry led consortium funded by the European Commission. It specified a BPL system based on OFDM, whose baseline technology was DS2’s technology, for providing access services in January, 2006††††† . UPA supports the OPERA specification. ETSI (European Telecommunications Standards Institute): An ETSI project of Powerline Telecommunications (PLT) has delivered a number of key specifications and reports for BPL. For example, ETSI TS 101-867 is a technical specification based on FDMA for coexistence of access and in-house power-line systems†††††† . TS 101-896 specified a reference network architecture model‡‡‡† . CISPR: The international EMC regulation applied to PLC modems is CISPR 22. Since the present regulation did not assume that a device would use one port simultaneously for both purposes of mains power supply and telecom, it has decided to revise the regulation corresponding to PLC devices [4]. 4.

Deregulation and EMC

The U.S.’s regulation (FCC part15) is so permissive as shown in Fig. 2 that the PLC modems compliant with the HomePlug standards have been sold at the stores in the U.S. and Canada. However, it is not allowed to use them in Japan because of the restriction by the Radio Law‡‡‡‡ . The Ministry of Internal Affairs and Communications (MIC), which is the presiding ministry of the Radio Law, established a task force on the PLC systems from April through July in 2002 to follow the scenario of e-Japan Priority Policy Program (March, 2001), and the possibility of the deregulation was discussed‡‡‡‡† . As a result, it became possible to execute field experiments since January, 2004‡‡‡‡‡ . † http://www.cepca.org/about us/Events/past events/japan sem inar/CEPCA Seminar Renesas.pdf †† http://grouper.ieee.org/groups/1901/ ††† http://standards.ieee.org/board/nes/projects/1775.pdf †††† http://standards.ieee.org/announcements/pr p1675.html ††††† http://www.ist-opera.org/DownloadSpec.php †††††† http://webapp.etsi.org/action/PU/20001114/ts 101867v01010 1p.pdf ‡‡‡† http://www.dcita.gov.au/ data/assets/pdf file/21755/ Powerline Telecommunications Appendix C - Architecture.pdf ‡‡‡‡ http://www.soumu.go.jp/joho tsusin/eng/Resources/laws/ 2003RL.pdf ‡‡‡‡† http://www.soumu.go.jp/s-news/2002/020809 4.html ‡‡‡‡‡ http://www.soumu.go.jp/s-news/2004/040121 1.html


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• FCC part 15 [16]: The limit values were converted into the values at a place 10 m away by using the attenuation coefficient reported by [5]. • Japan: Recommended limits by [5]. • CISPR 22: [17] Fig. 2 Limit value comparisons of the electric field strength values radiated from PLC modems.

From January to December, 2005, another task force on the high-speed PLC was established [5]. The recommended values of Fig. 2 by the task force were based on the decision of “It is preferable to suppress the unnecessary radiation from PLC modems to be below the surrounding electromagnetic noise level.” For example, the surrounding electromagnetic noise level in a rural area is so low that the transmitting power in the area should be lower than that in the business area. The mean value of the common-mode current that corresponds to the recommended value shown in Fig. 2 was 32 dBµA. The recommended limit of the commonmode current was set to be 30 dBµA (at the quasi peak, QP) under the condition of the longitudinal conversion loss (LCL): 16 dB and the common-mode impedance (CMZ): 25 Ω, where the limit was set to be almost the same as that of CISPR 22 (2005-04) [17]. Following the recommendation of [5], the discussion on “Permissible value and its measurement for high-speed PLC equipments” is continuing now at the CISPR committee under the Information communication council [6]. The upper limits of the common-mode current are proposed to be 30 dBµA at the range from 2 M to 15 MHz and 20 dBµA at the range from 15 M to 30 MHz, respectively† . The discussion is scheduled to be done until June, 2006. It can be said that the purpose of these discussions is to study the method for the coexistence of narrow-band systems (radio and broadcasting stations) with a wide-band system (PLC modems) in the same frequency band. This is a topic that we have not experienced so much up to now. The same topic is discussing for the deregulation of UWB (Ultra Wide Band) systems, too. Treating them as the electromagnetic environmental problem, they are the same as the management problem of the electric field strength radiated from the twisted pair cables for communication systems such as

xDSL†† and Ethernet [18]. It is feared that when the upper limit is decided once, the development of technology for decreasing the radiated electromagnetic field would stop at that time. The author thinks that it is necessary to make a regulation that doesn’t fix the limit value but decreases the value gradually according to the progress of the technology. To realize the higher speed modems while maintaining the EMC, it must reach the technology that lowers the power spectrum density (P.S.D.) by the spread spectrum modulation, although it is necessary to widen the allowed bandwidth enough to take the spreading gain enough. The author thinks that it is preferable to have an option in the new regulation which does not allocate the allowed frequency range strictly at the sacrifice of suppressing the limits of the conducted noise and the radiation††† That is to say, PLC will be interesting more and more if next generation’s PLC will be able to use a wider bandwidth even though the presently allowed bandwidth is about 30 MHz. 5.

Localization by Acoustic DS-CDM Signals

If the BPL is regarded as an alternative technology of IEEE 802.x under the restriction of the allowed frequency range being the HF-band, the steady technical innovation might be difficult because PLC essentially has the EMC problem. Then the author is groping for the applications which use the feature of PLC well. In this section, a localization method using PLC is introduced as an example. The method was studied to presume the position of a mobile node in the room (for instance, a home robot, a pet dog, and so on) with high accuracy by means of audible sound [19]. A wireless communication system that utilizes a power-line cable as an antenna, which can integrate the conventional PLC system, and a method using zero-crossing timing of the mains frequency to synchronize the devices for the localization are introduced bellow. 5.1 Principle The ranging mechanism is based on measuring time-offlight of audible signals through the air. After the range finder outputs Direct-Sequence Code Division Multiplexed (DS-CDM) audible signals simultaneously from two or more sound sources (i.e. speakers), which exist at given coordinate points, the time-of-flight of the individual audible signal is measured and the coordinate point where the mobile node is physically located in a room is determined. Since the acoustic velocity is quite slow, the proposing system can easily obtain the high resolution of several centime† http://www.soumu.go.jp/joho tsusin/policyreports/joho tsu sin/cispr/pdf/060605 si 5-5 1.pdf †† http://www.darc.de/referate/ausland/plc/ DARC-PLC4xRPRT.pdf ††† Option to treat the PLC modems as the radio stations operating with extremely low power of emission (Article 4 of the Radio Law) or inductive radio stations (Article 100 of the Low).


3010

and 4 cm, respectively, if there was no obstacle. Even if there were obstacles, the proposed method was possible to measure the location by the diffracted wave. If the obstacle was relatively small, its accuracy was within 5 cm. On the other hand, if the obstacle was relatively large, a method to determine the presence of a large scale obstacle was proposed in [19]. Although not verified yet, sufficient accuracy to perform the navigation of a home robot will be obtained by this localization system. Then, how to apply PLC to this system is described below. 5.2 PLC Speakers and Their Synchronization

Fig. 3 Principle of two-dimensional range-finding by acoustic DS-CDM signals.

ters at low cost when comparing to the conventional system using the radio or light wave. Moreover, the audible signal is suitable to prevent the Non-Line-Of-Sight (NLOS) problem that often occurs when the ultrasonic, light, or millimeterwave are used in the indoor environment, because the audible wave is more diffractive than those waves. On the other hand, the range-finding error becomes large when the node is placed behind a relatively large obstacle because the measured time is for the flight path of diffracted wave. Therefore the proposing system needs a function which indicates the reliability information to the range-finding results. Figure 3 shows the principle of two-dimensional rangefinding. The system is composed of two Windows PCs (1) and (2) into which a sound-card is built respectively, two speakers (1) and (2), and a microphone. The number of speakers is the same as the number of dimensions to be determined. Three kinds of sounds are output from PC(1) simultaneously, and one of them, denoted as output-timing sound, is input into PC(2) directly. The speaker-out sounds, which are denoted as M-sequences (1) and (2), are picked up with the microphone set up at a place l1 [cm] away from Speaker(1) and l2 [cm] away from Speaker(2), and are recorded by the stereo sound-card in PC(2). The arrival-time difference between the output-timing sound and the sound of M-seq. (1) or (2) is equivalent to the distance l1 or l2 , respectively. By solving the simultaneous equations, the coordinate of the microphone is obtained. Note that, since three kinds of M sequence are used in order to identify the sound source at the receiver side of PC(2), this is a kind of DS-CDM communications system. Let the sampling rate of the sound-cards R s and the speed of sound in the air v s be 48 kHz and 344 m/sec† , respectively. Then the resolution of our measurement is about 1 cm (= v s /R s ). The measurement accuracy is almost the same as the diameter of speakers. According to our scenario, the obtained average and worst accuracy of the localization in a 4 m2 plane was 1 cm

Many speakers have come to be installed in home in recent years. For example, there are a lot of TVs in a house, and a so-called home theater can be enjoyed with a 5.1 channel or more speaker system in a living room. There may be some interphones and some PCs in the house. These speakers will be interconnected by home network in the near future, so that we will be able to listen to the desired sound or even an urgent broadcast in a time of emergency wherever in a house we will be. As the home network technology, wireless LAN and PLC are promising. In this section, the speakers connected to the PLC network are called PLC-speakers†† . The author thinks that the reception function of the Emergency Warning System (EWS)††† sent by TV or the FM broadcast wave at the time of catastrophic disaster might be a function which the PLC speaker should support. And its automatic wakeup function of the related household-electricappliances is an application which is suitable for PLC systems. The above-mentioned localization system which is assumed to uses the PLC speakers is shown in Fig. 4 [20]. Usually the speakers are used to listen to the desired sound as mentioned above, and when performing the localization according to a user’s demand, the sounds of M sequences for localization are superimposed and the superimposed sounds are output from the speakers. Compared with Fig. 3, Fig. 4 differs in that the sound signal line which outputs/inputs from/to PC is wireless. When performing the localization, strict time synchronization is needed among speakers and a microphone. For example, in order to guarantee the range-finding accuracy of 5 cm, the required synchronization accuracy is 145 µsec (= 5 cm/vs ). Since it is difficult to guarantee this accuracy by the CSMA-type protocol used by the conventional PLC modems, a method of synchronizing each device with the mains frequency might be useful. According to the CEPCA technical-specifications [15], although the displacement of the zero-crossing timing occurred by the loads connected to the power-line, the maximum displacement in a house was less than 100 µsec. There†

v s = 331.5 + 0.61t, where t is the air temperature [◦ C]. An example of commercialization of the PLC speaker is http://us.marantz.com/Products/1545.asp. ††† http://www.nhk.or.jp/strl/results/activity/pdf/94-01.pdf ††


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AC power cord are taken into consideration, the frequency range from 20 M to 60 MHz is suitable for such wireless communications [20]. 6.

Fig. 4 Localization system with the PLC speakers and the power-line antenna.

fore, the usage of the zero-crossing timing is effective as a means for making the synchronization error be less than 5 cm. If the Beacon period shown in Fig. 1 is used, the author thinks that the synchronization method proposed in [20] will be realizable. 5.3 PLC Integrated with Wireless Communication by a Power-Line Antenna Since household-electric-appliances connected to a powerline and the wiring configuration of the power-line are not manageable, the common-mode current, which mainly causes the unnecessary radiation, is also not manageable usually. However, the wiring configuration of the AC power cord of a PLC modem, which influences the propagation property of the common-mode current predominantly since the cord is adjacent to the PLC signal source, is manageable. The authors have proposed a management method of the common-mode current by using a shielded AC power cord [20]. By shielding an AC cord, the electric length in the cord becomes manageable to be constant so that the cord becomes a feeder cable which resonates at a desired frequency. The connected power-line and the outer conducting sheath of the cord become the antenna elements, which are referred to as a power-line antenna. The reason why we paid attention to the power-line antenna as a manner of the signal radiation for time synchronization among speakers and a microphone was its wideness of the coverage area. By injecting common-mode signals into the shielded AC power cord, the signals are radiated along the cord and power-lines as shown in Fig. 4. Since the power-lines are already installed everywhere in a house, the signals will be able to be received everywhere in the house. Although the conventional PLC is a method of wired communications among household-electric-appliances connected to a power-line, if the concept of the power-line antenna is used together, electrical equipments which are not connected to the power-line will be possible to communicate with the appliances. The author names this concept “integrated wired and wireless PLC.” When the common-mode transmission characteristic of the VVF cable, which is often used as the residential power-line cable, and the length of the

Conclusion

This paper has overviewed the high-speed PLC technology, and the related standardization and regulatory activities have been described. PLC modems of 200 Mbps class become a practical use stage in the West, and the standardization activity is active now. The discussion for deregulation is being continued in also Japan, so that it is important to develop the PLC technology further which is suited to the Japanese power-line environment. As another topic in this paper, a sensor network application in consideration of the feature of PLC has been introduced, since the higher reliability can be expected by the use of the HF band compared with that of the conventional lower frequency band. The introduced topic has been an indoor fine-grained localization system by acoustic DSCDM signals. The obtained average and worst accuracy of the localization in a 4 m2 plane were 1 cm and 4 cm, respectively, if there was no obstacle. Even if there was an obstacle, its accuracy was within 5 cm if the obstacle was relatively small. To realize the localization system, some novel ideas, e.g. PLC speakers, a synchronization method based on the zero-crossing timing of the mains frequency, and integrated wired/wireless PLC, have been introduced. In the future work, the author will implement these ideas and continue groping for the applications which use the feature of PLC well. References [1] S. Tsuzuki, “Home network and sensor network by power-line communications,” IEICE Technical Report, SIP2005-62, July 2005. [2] Y. Morihiro and D. Umehara, “Integrated power and information delivery for wired ubiquitous networks,” The First Singapore-Japan International Workshop on Info-Communications Technologies for the Ubiquitous Networked Society, Dec. 2003. (available from http:/ /forest.kuee.kyoto-u.ac.jp/˜umehara/papers/domestic/200312.pdf) [3] S. Tsuzuki and Y. Yamada, “Trend in power-line communication using low frequency band and its application to home network,” Annual Journal of Engineering, Ehime University, vol.1, pp.121–130, March 2002. [4] Amendment to CISPR 22: Clarification of its application to telecommunication system on the method of disturbance measurement at ports used for PLC, IEC, CISPR/I/89/CD (COMMITTEE DRAFT), Nov. 14, 2003. [5] The task force on the high-speed PLC, The Ministry of Internal Affairs and Communications (MIC), http://www.soumu.go.jp/joho tsusin/policyreports/chousa/kosoku denryokusen/, 2005. [6] The CISPR committee, the Information communication technical subcommittee, the Information communication council, MIC, http:// www.soumu.go.jp/joho tsusin/policyreports/joho tsusin/cispr/cispr. html [7] S. Tsuzuki, “Home network using power-line,” The Journal of the Institute of Image Information and Television Engineers, TV Cafe, For your Information (42), vol.55, no.12, pp.1619–1620, Dec. 2001. [8] M. Katayama, ed., Power-Line Communication System, TRICEPS, WHITE Series no.219, July 2002. ISBN4-88657-219-7.


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[9] S. Tsuzuki, “The home network by power-line communication,” IEICE Technical Report, IN2003-168, Jan. 2004. [10] H. Hrasnica, A. Haidine, and R. Lehnert, Broadband Powerline Communications: Network Design, John Wiley & Sons, Aug. 2004. ISBN: 0-470-85741-2. [11] T. Koga, “Realizing the ‘No-Extra-Wired Solution’—High Definition ready, High Speed Power Line Communication,” May 26, 2005. (Available from Internet resources.) [12] http://www.internix.co.jp/products/intellon/index.html [13] S. Gavette, “HomePlug AV Technology Overview,” http://download. microsoft.com/download/a/f/7/af7777e5-7dcd-4800-8a0a-b183365 65f5b/HomePlugAVWP ShermanGavette.doc, April 18, 2006. [14] S. Gavette, “HomePlugAV—Detailed Architecture,” HomePlug Executive Seminar, http://www.homeplug.org/en/news/presentations/ japanexec 2005/HomePlugAVDetailedArchitecture-Gavette.pdf, Nov. 16, 2005. [15] CEPCA Technical Work Group, “CEPCA technological specification,” CEPCA Technical Seminar, http://www.cepca.org/about us/ Events/past events/japan seminar/CEPCA SeminarSpecification. pdf, April 2006. [16] Amendment of Part 15 regarding new requirements and measurement guidelines for Access Broadband over Power Line Systems/Carrier Current Systems, including Broadband over Power Line Systems, FCC-04-245, 28 Oct. 2004. (Available from http://hraunfoss.fcc.gov/edocs public/attach match/FCC-04245A1.doc) [17] F. Amemiya, “The decision reason of limit values of conducted disturbances at a telecom port given in CISPR 22, and a proposal concerning the coexistence condition,” the task force on the high-speed PLC (the 4th meeting), Material 4-4, April 14, 2005. (http://www.soumu.go.jp/joho tsusin/policyreports/chousa/kosoku denryokusen/pdf/050414 2 s4.pdf) [18] N. Kuwabara, “EMC technology trend of telecommunication systems,” J. IEICE, vol.84, no.12, pp.869–872, Dec. 2001. [19] N. Takeichi, S. Tsuzuki, and Y. Yamada, “A study of an indoor finegrained localization method by acoustic DS-CDM signals,” IEICE Technical Report, SN2006-7, Jan. 2006. [20] S. Tsuzuki, N. Takeichi, M. Hamada, and Y. Yamada, “A proposal of synchronization beacon systems over power-line for indoor finegrained localization,” IEEE International Symposium on Powerline Communications and Its Applications (ISPLC 2006), pp.143–148, Orlando, USA, March 2006. ISBN 1-4244-0112-7.

Shinji Tsuzuki received the B.E. and M.E. degrees in electronics engineering from Ehime University (Japan) in 1983 and 1985, respectively, and the Doctorate degree in engineering from Kyoto University (Japan) in 1999. He joined Sumitomo Electric Ind., Ltd. in 1985. He was engaged in the research and development of Fiber-optic Local Area Network systems. Since 1991 he has been in the Faculty of Engineering of Ehime University, where he is currently an Associate Professor. During 1996-1997 he was a visiting scholar at Kyoto University. His research interests include spread spectrum communication, and network access techniques. He is a member of SITA, ITE, IEEJ, IPSJ, and IEEE.