Wr@p the last meter technology for energy aware networked smart appliances


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This paper presents a detailed analysis of Wr@p technology (Web Ready Appliances Protocol, also known as Power Modulation), an ultra-low-cost powerline communication solution devoted to the electrical appliance market. Wr@p technology is aimed at adding communication capability to a household appliance without affecting its industrial cost, thus speeding up the diffusion of “smart” appliances interacting with the power distribution grid and contributing to the smart grid paradigm.
A Wr@p transceiver establishes a narrow-band powerline communication exploiting the “last meter”, i.e. the power supply cord between the appliance and the outlet, where a proxy device, the smart adapter (SA), flexibly deals with standard home networking solutions. At the appliance side, such an approach allows for (i) connectivity at negligible cost and, (ii) keeps hardware and software virtually independent from the actual home networking protocol (since different configurations of the smart adapter take care of it). In this work, after recalling the basics of Wr@p point-to-point communication, an extension to the multipoint-to-point scenario is introduced. Design of silicon implementations integrated into commercial microcontroller architectures are presented and the results of extensive test of fabricated devices under actual operating conditions are detailed. Moreover, we present a complete Wr@p development solution, featuring wireless networks integration.

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Wr@p the last meter technology for energy aware networked smart appliances

  1. 1. Wr@p: the Last Meter Technology for Energy-Aware Networked Smart Appliances A. Ricci∗ , E. Smargiassi§ , D. Mancini¶ , I. De Munari∗ , V. Aisa and P. Ciampolini∗ ∗ Dept. of Information Engineering, University of Parma, Parma, Italy. Email: andrea.ricci@unipr.it § Elite s.c.p.a., Fabriano (AN), Italy. Email: enrico.smargiassi@elitetech.it ¶ SPES s.c.p.a., Fabriano (AN), Italy. Email: davide.mancini@spesonline.com Indesit Company S.p.A., Fabriano (AN), Italy. Email: valerio.aisa@indesit.com Abstract—This paper presents a detailed analysis of Wr@p1 meters and the power distribution network through suitabletechnology (Web Ready Appliances Protocol, former Power Mo- communication infrastructures. Unfortunately, there are stilldulation), an ultra-low-cost powerline communication solution objective problems relating to connectivity that hinder thedevoted to the electrical appliance market. Wr@p technologyis aimed at adding communication capability to a household rapid and wide spread of these innovative home products.appliance without affecting its industrial cost, thus speeding up In the past, several network protocols have been proposedthe diffusion of “smart” appliances interacting with the power- for control and monitoring of the domestic environment (e.g.,distribution grid and contributing to the smart grid paradigm. LON [1], Konnex [2], Ethernet [3], WiFi [4], ZigBee [5]-[7]);A Wr@p transceiver establishes a narrow-band powerline com- however, expensive communication nodes, as a matter of fact,munication exploiting the “last meter”, i.e. the power supplycord between the appliance and the outlet, where a proxy can only be embedded into high-end household appliances,device, the smart adapter (SA), flexibly deals with standard home which are capable of bearing their unavoidable cost increase,networking solutions. At the appliance side, such an approach whereas “standard” communication technologies are precludedallows for (i) connectivity at negligible cost and, (ii) keeps to mass production of middle-range and low-end “whitehardware and software virtually independent from the actual goods”. Moreover, market has not converged yet on a single,home networking protocol (since different configurations of thesmart adapter take care of it). In this work, after recalling the common home-networking standard, which makes the protocolbasics of Wr@p point-to-point communication, an extension to selection a multifaceted issue, leaving the field open to newthe multipoint-to-point scenario is introduced. Design of silicon smart solutions. To overcome all these problems, an originalimplementations integrated into commercial microcontroller ar- approach has been proposed in [8]-[13], based on a “proxy”chitectures are presented and the results of extensive test of approach (Fig. 1): bidirectional narrow-band point-to-pointfabricated devices under actual operating conditions are detailed.Moreover, we present a complete Wr@p development solution, communication (called Power Modulation or Wr@pTM ) isfeaturing wireless networks integration. established on the power-supply wire, between each appliance Index Terms—Powerline communication, smart appliance, mi- and its outlet. A general-purpose communication node (calledcrocontroller peripheral, smart grid, smart plugs, ZigBee. Smart Adapter, SA) is located at the outlet and acts as a bridge between the Wr@p communication and the actual home I. I NTRODUCTION networking protocols. By this approach, several advantages Nowadays, the constant growing demand for energy and the may be attained: (i) communication costs at the applianceantithetical call for climate changes reduction are producing side are negligible (transmission is managed by the appliancea strong convergence of scientific, industrial and political control core itself by means of on-board peripheral); (ii) theinterests towards the use of information and communication appliance hardware and software are virtually independent oftechnologies (ICT) in order to support a structural transfor- the actual home networking protocol, which is allotted to themation of each phase of the energy cycle: from generation to external smart adapter; (iii) new generation of smart plugs andtransmission, from distribution to accumulation and, above all, smart sockets can be designed, which are able to talk directlythe smart consumption of energy. This virtuous link between to plugged household appliances and spread the collectedICT and the world of energy is commonly identified with information to the grid; (iv) the in-line production testing ofthe term Smart Grid, or even Internet of Energy, in order appliances can be improved and accelerated; (v) appliances canto highlight a paradigm shift that leads to a global network be remotely assisted without adding any cost to the product.that carries energy, information and control between highly In this paper, we report on Wr@p technology updates,distributed and cooperating devices and systems. This process development tools as well as applications. The contributions ofof great transformation of the global energy system involves the paper are the following: (i) an extension of basic point-to-the direct collaboration of household appliances, in particular point transmission concept to the multipoint-to-point scenariowhite goods, which, to this purpose, are becoming “smart” and by means of medium-access-control (MAC) techniques; (ii) awill be able to exchange information with both digital power description of silicon implementation of Wr@p communica- tion circuitry into commercial 8-bit and 32-bit microcontroller 1 Wr@pTM is a trademark owned by Indesit Company SpA, Italy. architectures; (iii) the analysis of Wr@p protocol mapping
  2. 2. receiver transmitter transmitter receiver LS1 I DA zc1 D1 D2 zc2 Vs Vs mod ZPM BPF ZDA M1 M2 T1 shunt m(t) power supply cord PM Power meter SoC PM-enabled appliance PC peripheral Smart Adapter (a) Digital Household Appliance (b) Fig. 1. Wr@p communication system: (a) smart adapter, (b) digital household appliance.on ZigBee interoperable application layer (i.e. Cluster Library short (few tens of microseconds) and precise perturbationslevel). (about 12 V in amplitude), superimposed to the mains voltage The paper is organized as follows. In Section II, Wr@p waveform. Data are encoded by modulating the positions, withtechnology basics are recalled and multipoint-to-point commu- respect to the zero-crossing of supply sine waveform. Fig. 2nication is introduced. Section III gives details about cirtuitry shows the smart adapter transmission section, where a digitalimplementations, in the form of microcontroller peripherals device (e.g. the digital core of a power meter system-on-chip)and smart plugs, whereas in Section IV we describes the controls current flowing through zener diodes (D1-D2) byfusion of Wr@p communication with wireless networks. In means of a couple of MOSFETs (M1-M2) and a relay (LS1).Section V we present our experimental results, based on At the appliance side, reception is based on an extremelyWr@p development kit. Finally, in Section VI, we draw the cheap analog front end (i.e. a band pass filter plus a couplemain conclusions of the paper. of Schmitt-triggers) and a few configurable digital counters, again embedded into PM peripheral. Information data have to II. W R @ P N ETWORK AND P ROTOCOL be duplicated and encoded four times per period, in order to Details of Power Modulation (PM) physical link can be ensure that at least one pulse will trigger the receiver. Datafound elsewhere [13]. Here, we just recall its basic prin- duplication within each sine wave semi period (one instanceciples (see Fig. 1): the forward link (from the appliance per quarter) is used to cope with unknown nature (capacitiveto the smart outlet) is based on the on-off keying (OOK) or inductive) of the appliance load. Plug orientation does notmodulation of the instantaneous power consumption of the impact on decoding procedures thanks to the data replicationappliance, in a synchronized fashion respect to the mains over adjacent mains semi periods. Measurements demonstratecycles. The appliance should include a Power Modulation- that it is possible to transmit at least one nibble (i.e. 4enabled microcontroller (i.e. a device which features a simple bits) during each mains cycle, without exceeding noise limitsPM peripheral, see Section III) and, at least, one inexpensive set by regional standardization committees (e.g., CENELECelectric load (ZPM ) - any electric load of the appliance itself, in Europe) and preserving the proper functionality of thefor instance - controlled through a triac (T1). If a single bit appliance.per period is transmitted, depending on the mains frequency, At the appliance side, the digital encoding and decod-a throughput of either 50 or 60 bit/s can be achieved. This ing procedures have been embedded into a microcontrollerrelatively slow communication perfectly matches the typical peripheral, in order to (i) keep costs at a minimum andappliance data notification scenarios: both white goods status (ii) guarantee performance and repeatability of operations.and faults monitoring, as well as statistical and diagnostic data Household appliance manufactures can embed Wr@p-enabledcommunication actually require the transmission of few bytes. microcontrollers into their products free of charge, thanks toAt the receiving side, a simple power meter is needed, in order the recent Power Modulation technology liberalization2 .to reveal incoming data. Each bit is decoded by measuring A. Data-Link Layerthe mean power absorbed by the appliance during each k- Data-link layer relies on a packet-based communication.th cycle and comparing it to an adaptive reference threshold The Power Modulation frame format is composed of a header,(i.e. the weighted average over the n previous cycles’ power a payload and a footer checksum. The general PM frameconsumption). The decoding scheme is very robust and reliable structure is formatted as illustrated in Fig. 2. Packet Headerif simple power consumption oversampling is used. On the is 3-byte in length, and contains synchronization preamble, areverse link (from the smart outlet to the appliance), databits are encoded according to a pulse position modulation 2 Agreement between Indesit Company and Renesas Electronics signed on(PPM) scheme. The smart adapter generates intentional, very March 29th, 2010
  3. 3. Octets 3 0 to 32 2 count ^I/2,I/4,..,I/32` Noise canceler PMVZ Header Payload Footer I Noise canceler PMPZ Prescaler PMUGR CRC-16 checksum PMCR Frame synch Command Length optional Receiver Transmitter PMT forward-link Bus Interface half bit 0xA5 : forward link (from DA to SA) 0x00 : reverse link (from SA to DA) Fig. 2. Data-link layer frame structure. PMDR PMCDR DDC/frequency Voltage Module measurement measurement data bus PMSR Local serial bus PMSR2 Interrupt (a) generator Power Modulation Interface Home Application Metering network node processor circuitry CPU Internal data bus Other peripherals (b) Fig. 4. Power Modulation peripheral architecture, integrated in both 8-bitFig. 3. Multiple smart adapter (MSA) devices: (a) replicated metering H8/36079PMI and 32-bit RX210 microcontrollers.circuitry; (b) PM channel sharing.command identifier and payload length sub-fields. solution, Fig.3(a), requires several replicas of the meteringDuring forward link transmission, Frame synch byte is set circuitry, one for each connected appliance. The MSA embedsto 0xA5, in order to enable smart adapter for power threshold only one standard home-networking node, which routes allestimation (i.e. 0xA5 contains an equal number of high and the collected information coming from each PM channellow bits). An optional high half-bit can be added at the end towards the residential network. Depending on the selectedof forward link frames, providing smart adapter with plug metering device some optimizations could also take place ininsertion information (i.e. transmission reference). the metering section: if advanced SoCs are selected (featuringThe reverse link exploits 0x00 as frame synchronization pat- digital programmable cores and multiple conversion channels)tern; at the receiver side, the difference between nominal and only current detector replicas are actually required, in order toactual pulse positions is computed and offset compensation is talk simultaneously with several digital appliances.applied to the following frame data. The Command identifier When device cost and size reduction is the main MSA designsubfield specifies the packet class being used. Valid commands driver, some more savings can be attained, trading cost withinclude appliance identification and arbitration (see II-B) as bandwidth. Following this second approach, all the availablewell as white good control and monitoring classes. The sockets are connected in parallel (Fig.3(b)) and the PowerLength byte specifies the payload field byte count whereas Modulation channel is shared among white goods, accordingthe Checksum, based on standard CRC-16-CCITT generator to a TDMA policy, i.e. the available channel is divided,polynomial, enables for communication error detection. A along the time dimension, between potential participants. Thesimple stop-and-wait ARQ retransmission policy can be imple- procedure of collision avoidance is a SA-driven synchronousmented, in order to reduce physical layer bit-error-rate (BER) mechanism, with all the appliances’ data transfer handled byon both forward and reverse link. The experimental analysis, the smart adapter, by means of a singulation process. Thedetailed in Section V, regardless of the operating conditions selected anticollision scheme is a conventional binary tree-(i.e. static or time-varying loads), indicates a residual BER based algorithm (used, for example, in passive RFID systems)figure well below 10−6 at the data-link layer, which is more and can be implemented inside the SA application microcon-than adequate to the actual purpose. troller. In order to partecipate to the arbitration sessions, each appliance requires an unique identifier (ID), either assignedB. Multipoint-to-Point Communication during production phase (e.g. a subset of manufacturer codes) Basic “single-access” smart adapter device (SSA) featuring or randomly generated. The appliance ID length can be limiteda point-to-point Power Modulation link can be extended to a to one byte, thanks to the reduced number of appliances whichmultipoint-to-point scenario, i.e. several household appliances share the same medium (usually up to 5-10). The tree-basedtalking with a multi-socket smart adapter (MSA) device. algorithm represents a two-way handshake process involvingThis multiple “proxy” service can be implemented following sequences of interaction between the smart adapter and themainly two approaches, depicted in Fig.3. The straightforward appliances, known as the interrogation cycle. The objective
  4. 4. TABLE Iof these interrogation cycles is to split the appliances, using ATTRIBUTES OF THE W R @ P P ROTOCOL T UNNEL S ERVER C LUSTER .their identifier, into reduced sets of devices. The splitting ofthe IDs binary tree into two branches (leaves) is based on the ID Name Type Access Man./ Opt.bit collisions. Obtaining collision information at the bit level 0x0000 SmartAdapterClass 8-bit Read-only Mcan be revealed at the smart-adapter side observing deviations enumerationfrom nominal appliance absorbed currents (estimated during 0x0001 DeviceActiveMask 16-bit bitmap Read-only M 0x0002 DeviceComMask 16-bit bitmap Read-only Mpacket preambles). Through singulation process, the smart 0x0003 DeviceIDList Array of Read-only Oadapter collects the identifiers of plugged appliances. After this unsigneddiscovery phase, SA can talk directly with each white good or 8-bit integerit can assign each appliance a time slot for spontaneous data TABLE IInotifications. C OMMANDS ID S FOR W R @ P P ROTOCOL T UNNEL S ERVER C LUSTER .III. P OWER M ODULATION P ERIPHERAL I MPLEMENTATION Commands Received In cooperation with Renesas Electronics Corporation, we Command identifier Description Man./Opt. field valueinvestigated Wr@p technology implementation, based on the 0x00 Wr@p Frame Transmission Mintegration of communication physical layer within commer- Requestcial microcontroller architectures as a dedicated peripheral 0x01-0xff Reserved -(referred as Wr@p Interface or Power Modulation Interface, Commands Generated Command identifier Description Man./Opt.PMI) . The impact on silicon area of the microcontroller field valuewould be almost negligible, and software code of PM data- 0x00 Wr@p Frame Transmission Mlink layer would result extremely simple, thus leading to Response 0x01-0xff Reserved -a cost- and performance-effective solution. Hence, we havedesigned a digital architecture implementing the PM manage-ment functionalities. VHDL language has been exploited to Octets 3 0 to 32 2 countthis purpose. The Power Modulation Interface (PMI) block Wr@p data-link frame structure Header Payload Footerdiagram is reported in Fig. 4. The architecture includes both CRC-16communication modules and a mains line monitor block. The checksum octets(2-34)latter could be profitably exploited to enable demand-side Frame synch Command Length optional forward-link octet(1)power management policies. As an example, measuring the octet(0) half bitmains voltage frequency the power-grid actual load status canbe inferred: adapting the user’s load to the grid health status, Frame Man. code Transaction Command control sequence identifierfluctuations. in the power requirement could be smoothed out, numberthus reducing the need for spinning reserves (i.e. on largenumbers, reducing greenhouse gas emissions) [14]. PMI is ZigBee ZCL-level ZCL Header ZCL frame payload frame structureextremely flexible: more than ten 8-bit registers give accessto several peripheral configurations, enabling the adaption of e.g. Wr@p Frame 0x00 DeviceID Wr@p octets(0,1,..,34) Transmission Cmdcommunication capabilities to different scenarios. First, thephysical implementation of PMI (which requires less than 10 k Fig. 5. Wr@p protocol mapping into ZigBee application layer (exploitingequivalent gated) has been carried out on a FPGA device, and ZCL approach).tested on Renesas E6000 development system [13], [15]. Then,the peripheral soft-IP has been integrated into two Renesasmicrocontroller architecture, both a 8-bit H8 Tiny and a 32- appliance networking are currently under discussion, based onbit RX210 device. Energy@Home3 initiative [17]. Moreover, ZigBee have been selected as the communication solution for several commercial IV. W R @ P TO Z IG B EE M APPING “smart plugs” devices. As already stressed above, the smart adapter device em- The fusion of Wr@p protocol and ZigBee stack has beenbeds a conventional communication node, in order to route performed at the application level, following ZCL (ZigBeeincoming Wr@p messages toward a home network. General- Cluster Library [6]) specifications, in order to preserve appli-purpose modular adapters can be designed, sharing design cation profiles modularity. A specific tunneling cluster can beand manufacturing costs on larger production volumes. Smart build, including both server and client on an endpoint to tunneladapter devices can then be personalized, simply adding the Wr@p messages in both directions.preferred communication module and mapping Wr@p networkcommunication onto the selected protocol. 3 Energy@Home is a collaborative project between Electrolux, Enel, Indesit Here, we detail Wr@p-to-ZigBee mapping, since home Company and Telecom Italia, aimed at developing a communication protocol that enables provision of Value Added Services based upon informationautomation [7] and smart energy [16] interoperable application exchange related to energy usage, energy consumption and energy tariffs inprofiles are already available and some extensions related to the Home Area Network (HAN).
  5. 5. TABLE III Digital Appliance board with E XPERIMENTAL E RROR B IT R ATE OF W R @ P P HYSICAL L AYER . Wr@p-enabled microcontroller Smart Adapter Expansion: Load BER H8-36079PMI C AFE C section to home network Capacitive Filter 3.75E-6 with PM peripheral M1 M2 (e.g. ZigBee) 10W Lamp 4.52E-6 Electric Motor (light routine) 5.62E-6 D1 D2 Electric Motor (medium routine) 6.25E-6 AFE Power Meter LS1 Electric Motor (heavy routine) 7.12E-5 SoCThe proposed server cluster contains the attributes shownin Table I. The read-only SmartAdapterClass attributespecifies the proxy category (i.e. single, multiple withreplicated power meters (MSA-P), multiple with arbitra-tion (MSA-A)). When multiple power meters are available, 3.3 VDeviceActiveMask and DeviceComMask bit masks rep- regulatorresent the active (i.e. consuming power) and Wr@p en-abled devices, respectively. The array of unsigned integerDeviceIDList contains appliances IDs retrieved either di-rectly or during the last arbitration session. All the attributes Appliance loadcan be read using cross-cluster ZCL commands and automat-ically notified supporting ZCL attribute reporting. The clientcluster has no attributes.Table II lists both received and generated commands whereas Appliance power supply cordFig. 5 details the basic mapping strategy. The ZCL Payload (Power Modulation channel) To the mains outletshould be filled with target Wr@p-enabled appliance ID Digital Appliance Smart Adapter(DeviceID), followed by the actual Wr@p frame content, i.e.Command, Length and Payload. The client cluster receives Fig. 6. Wr@p first development kit, based on H8/36079PMI microcontrollerthe cluster specific commands generated by the server and and wireless-enabled smart adapter.viceversa.Since the ZCL command payload length is limited to 35bytes, the Wr@p tunnel cluster does not require ZigBee field test, exploiting Wr@p development kit. To this purpose, afragmentation support, even if over-the-air High Security mode set of static and time-variable appliance loads were connectedis used. to the powerline, to simulate the actual operating environment.For single smart adapters, the proposed cluster could share its First, measurements were performed using a barely resistiveend-point with other services, such as Simple Metering cluster load, represented by a small lamp, always connected to the[16], as well as Appliance Identification and Control clusters power supply cord at the appliance side. The same device[17], creating an enhanced appliance-aware “smart plug”. A was also exploited to perform downstream communication,similar approach can be used for multiple smart adapters, modulating the current flowing over the power supply cord.where multiple end-points (one for each power meter) may Next, capacitive and time-dependent inductive loads werebe implemented on the same ZigBee device. Following the taken into account, by connecting actual household appliancesproposed ZCL-level tunneling approach (largely adopted in to the network. Capacitive behavior was obtained, as anthe ZigBee specifications), a Wr@p communication channel example, exploiting appliance power-supply filters, whereascan be instantiated inside every ZigBee devices, in a Smart an inductive load was given by the washing-machine electricalEnergy/Home Automation compatible fashion. engine. Time-dependent behavior was induced by performing several different cycles with a washing-machine. We collected V. W R @ P D EVELOPMENT K IT AND F IELD T ESTS statistical data during repeated communication sessions (3·107 The new microcontrollers, H8/36079PMI and RX210, have information bits for each load state). Table III resumes theeventually been fabricated and the former has been integrated experimental error bit rate of physical layer, evaluated underinto the first Wr@p development kit, depicted in Fig. 6. the different operating environments. The analysis, regardlessThe kit includes a prototypal generic appliance main board of the load conditions (static or time-varying loads) andand a smart adapter. The development solution enables for thanks to simple error-correcting (ARQ) software procedures,testing communication and line monitoring features under indicates a BER figure well below 10−6 at data-link layer,actual operating conditions. After preliminary functional tests, which is more than adequate to the actual purpose. Moreover,used to validate the communication principle and investigate depending on the microcontroller main clock frequency (2÷32the microcontroller peripheral performance, an extensive set MHz), peripheral clock (after the prescaler) spans from 1 toof experimental measurements was carried out in a thorough 1.875 MHz, enabling for a 0.005% minimum precision in the
  6. 6. detection of mains period. (Country Manager, Renesas Technology) and Mr. Massim- iliano Mazzoni (OEM Sales Manager, IBG Italy) for wafer VI. C ONCLUSIONS fabrication and their wide support to this work. In this paper, we presented Wr@p technology, a straight- A special thank to Mr. Andrea Merloni, President of Indesitforward and extremely cheap powerline communication tech- Company SpA (WRAP SpA President during Wr@p technol-nology devoted to household appliances networking. Wr@p ogy development) for his initiative to liberalize Wr@p tech-approach overcomes all the obstacles experienced by white nology in cooperation with Renesas Electronics Corporation.goods manufacturers when using “standard” communicationprotocols, by transferring higher-level communication tasks R EFERENCESto an external “proxy” device. The proposed architecture [1] Echelon Corporation, LonTalk protocol specification, version 3.0. 1994.represents a cost-effective solution which could foster the [2] Konnex Association, KNX Standard. 2001. [3] Institute of Electrical and Electronics Engineers, Inc., IEEE Std 802.3.diffusion of “intelligent” appliances: PM-enabled products IEEE Computer Society, 2002.could communicate with a local network, interacting with [4] Institute of Electrical and Electronics Engineers, Inc., IEEE Std 802.11.residential energy management tools and gaining relevant IEEE Computer Society, 2002. [5] ZigBee Alliance, ZigBee Specification (Document 053474r17), Jan.commercial advantages from new web-based services (remote 2008.assistance, preventive maintenance, etc.). With the help of [6] ZigBee Alliance, ZigBee Cluster Libary Specification (DocumentWr@p technology, a further step towards the development 075123r02ZB), May 2008. [7] ZigBee Alliance, ZigBee Home Automation Public Application Profileof the so-called smart grid can be made: in the near fu- (Document 053520r26), Feb. 2010.ture, the continuous real-time two-way information exchange [8] V. Aisa, WRAP SpA, International Patent WO 02/21660 A1.between utilities and “energy-aware” appliances will enable [9] V. Aisa, WRAP SpA, International Patent WO 02/21664 A1. [10] L. Burzella, F. Nocera, L. Morbidelli, B. Vinerba, M. Conti, WRAPeach customer to manage his energy behaviors depending on SpA, International Patent WO 2007/045946 A1.power supply availability and prices, thus supporting the global [11] V. Aisa, P. Falcioni and P. Pracchi, “Connecting white goods to a homeefficiency of the grid and reducing the environmental impact. network at a very low cost,” International Appliance Manufacturing, pp. 14-20, 2004. [12] A. Ricci, V. Aisa, V. Cascio, G. Matrella, and P. Ciampolini, “Connecting ACKNOWLEDGMENT electrical appliances to a home network using low-cost power-line The authors would like to thank Mr. Yoshinori Suzuki communication,” in Proc. of the 9th ISPLC, pp.300-304, Apr. 2005. [13] A. Ricci, V. Aisa, I. De Munari, V. Cascio, P. Ciampolini, “Implementa-(Group Manager MCU Design Dept. 5, MCU Systems Divi- tion and test of a power-line based communication system for electricalsion, Renesas Electronics Corporation), Mr. Terukazu Watan- appliances networking,” in Proc. of the 2006 ISPLC, pp. 239-244, Mar.abe (Associate General Manager, General Purpose MCU 2006. [14] A. Ricci, et al., “Power-grid load balancing by using smart homeSystems Division, Renesas Electronics Corporation), Mr. appliances,” in Proc. of the 2008 ICECS, pp. 1-2, Jan. 2008.Norishige Kawashimo (General Manager, General Purpose [15] Renesas Technology Corp., H8/300H Series E6000 Emulator, UsersMCU Systems Division, Renesas Electronics Corporation), Manual, rev. 2.0, version 12.12.2000. [16] ZigBee Alliance, ZigBee Smart Energy Profile Specification (DocumentMr. Graeme Clark (Product Marketing Manager at Renesas 075356r15), Dec. 2008.Technology America Inc./Europe Ltd), Mr. Andy Harding [17] Energy@Home Consortium, Energy@Home Technical Specifications,(Digital Home Business Group Manager, Industrial Business Revision 0.7, Aug. 2010.Group, Renesas Electronics Europe), Mr. Enzo Della Calce