Powerline communications

History

The transmission currents are used for a certain time in low flow for industrial applications and of house automation It is only since the beginning of the Années 2000 and the generalization of all-numerical that it is used by the general public.

1950 : first applications on Frequency 10 Hz, power 10 kw. They are then one-way (public lighting, remote control of relay)
Années 1980: beginning of research to use the waveband 5-500 Khz, always into one-way, thus allowing a faster transfer of information
Years 1990: experiments of the transmission currents for applications remote readings in the band 60-80 Khz. Appearance of transmission current modems low-flows for communications CPL house automations in Europe (standard EHS/Konnex) and in the United States (standard Level and CEBUS)
1997: research on the transission of data in CPL and bidirectional by Ascom (Swiss) and Norweb (the U.K.)
2000: first experiments in France by EDF R & D and Ascom
2002: SPIDCOM Technologies, new French company, arrives on the market with its processor of 224 M Bit the /s, “fastest in the world” at the time.
2002 : WIRECOM Technologies, also new French company, specialized in the energy management of the building on CPL (technology low-flow - standard CENELEC EN50065-1)
2003: acquisition by Schneider Electric of the company Swedish Ilevo, specialized in the powerline communications, and creation of the new entity Schneider Electric Powerline Communications, dedicated to the supply of equipment, software and services around the powerline communications.

Operation

The principle of the CPL consists in superimposing on the electric current of 50 Hz a signal with more high frequency and of weak energy. This second signal is propagated on electrical installation and can be received and decoded remotely. Thus signal CPL is received by any receiver CPL which is on the same electrical communication.

One traditionally classifies the CPL in two categories according to the flow offered. The CPL with high banc use multiporteuses modulations of type OFDM in the band (band 1,6 to 30 MHz). The CPL with low flow use techniques of rather simple modulations, for example some carrying (but only one at the same time) in Frequency modulation. The bands of the frequencies used lie between 9 and 150 Khz in Europe and between 150 and 450 Khz in the United States (there are no radios large-waves in the USA).

In top as in low flow, the communication is subjected to noises and strong attenuations. It is thus necessary to implement Redondance, for example in the form of error correcting codes.

A Coupleur integrated in entry of receivers CPL eliminates the components low frequencies before the treatment of the signal.

The Modem transforms a flow of bits into analogical signal for the emission and conversely in reception, this one includes the functions of addition of the Redondance and reconstitution of the original flow of bits or correction of error.

Disadvantages

So in the principle this technique seems rather tempting, it even presents nevertheless notable disadvantages related to its principle. The signal high frequency generated by the modem is conveyed by wire of the sector, but these wire were not designed initially to convey such a type of signal. These wire sectors are thus transformed quite simply into antennas and radiate waves high frequencies in all the environment. According to the quality of electrical installation and electromagnetic insulation , these waves can be propagated and be disturbing until several hundred meters. In this case the materials sensitive to the high frequency but also, quite simply, the radio operator receivers in short waves, can be pertubés. In the same way, signal CPL in itself can be disturbed by the electromagnetic flows emitted by screens of computers, transformers…

There do not exist final Norme S concerning the CPL. It is thus not rare to find modems whose radiations go well beyond the standards of CEM (electromagnetic compatibility) imposed on the other materials. If the density of network is low, the risks to disturb the vicinity remain weak. Contrary, in buildings or zones where the density of such networks would be high, the electromagnetic interference could become intense. For this reason, in the hospitals, the CPL are not well accepted. In certain countries, this technology tends to being abandoned, at least in the field of access Internet, so much the problems of vicinity and of environmental disturbances are likely to be insoluble.

Typical applications

Technique CPL high-flow makes it possible to make pass from the computer data on the electrical communication, and thus to extend a existing Lan or share an access existing Internet via the electrical outlets thanks to the installation of specific cases. In the actual position of the technique, the flows reached are included/understood enters 14 Mbit/s and 200 Mbit/s (produced based on the Chipset DS2).

Technique CPL low-flow is addressed mainly to two applications. The standard house automation EHS/Konnex uses the CPL to put in network electricals appliance in fields as various as the washing machines, the travelling shutters, the heating. One uses also the CPL low-flow for business applications of and electric distribution or the remote reading grid system of the electric meters. The flows are typically from 2,4 to 20 kbit/s.

Legal framework and regulation

Any technology which works on a definite waveband must return in a legal framework. Networks CPL are at the same time electrical communications and telecommunication networks, with the result that the authorities have evil to define their legal framework. Moreover, there does not exist yet of precise regulation for the equipment and networks CPL. Work is in hand, in particular with PLC Forum and the ETSI, but the results were not published yet.

Thus the installation of networks CPL is free as regards the installations behind a private meter (one speaks about “Indoor” or “InHome”), subject to not creating harmful effects, in which case the material must be withdrawn.

As regards the external installations (called outdoor ) where one injects the signal on the level of transformer HTA/BT for creations of local loops electric, authorizations of experimentation are in general necessary, according to the country concerned. Thus, in France for example, such authorizations are to be required near ARCEP (ex ART) as long as technology is not mature and that the standards are not published.

With the Luxembourg, such tests ( outdoor ) realized as of year 2000 were immediately stopped, because they generated so important disturbances that they endangered the approach of the national airport (Findel) by the airliners. Noting that the disturbances were inherent in technology, this one was immediately given up by the national distributer of electricity (Cegedel). The current location is there that the Luxembourg authority of regulation (ILR) tolerates the sale of material " indoor" while waiting for a European regulation, but ensures that very felt sorry for interferences, even emitted by material authorized by law to come, will be followed of an investigation with series of measurements and, if radioelectric pollution is proven, of the confiscation of the material.

Currently, there is not, in European Union, of legislation which guarantees the perenniality of an installation based on technology PLC. While thus choosing this technology, one is likely to strongly disturb the authorized users of the frequencies radios, but moreover, one is likely to see oneself withdrawing his infrastructure network with the improvist, without speaking about possible fines for violation of the regulation on the use of the radio frequencies.

In 2005, in France, ART raised the experimental character which framed deployments CPL:

Paris, on Wednesday, April 20, 2005.

The Authority raises the experimental character which framed until now the deployment of the telegraphic networks in CPL.

The Regulatory agency of telecommunications raises the transitory statute which was until now applied to the telegraphic networks based on the technology of Powerline communications (CPL).

The Authority has just carried out an assessment of the experiments of the telegraphic networks based on the technology of the Powerline communications. The analysis of the various reports/ratios made it possible the Authority to make sure that the telegraphic network operators based on this technology can face the obligations related to the authorization of network open to the public. These experiments also made it possible to validate: - the possibility of division, by several suppliers of access to Internet, of the capacity offered on a network CPL, - the quality of service offered on the network in term of flows guaranteed, establishment and maintenance of bond Internet, - the absence of jamming throughout all expérimentations.

the Authority thus considers that the constraints which had justified the experimental statute retained during the instruction of the first request for network CPL are not relevant any more today.

In addition, a recent European recommendation relating to the CPL, published on April 12th, indeed requires of the Member States to eliminate " any unjustified lawful obstacle " and explains how to apply the provisions of the directive on electromagnetic compatibility. The actors wishing to deploy telegraphic networks CPL thus fit now fully in the regulation framework. They are invited to declare itself as operators near the Authority, in accordance with the article L. 33-1 of the Code of the Stations and the Electronic communications. They will have to also respect the regulation concerning electromagnetic compatibility ART wishes that beyond these first experiments the telegraphic networks| Regulatory agency of Telecommunication|

Standardization

In high-flow, the standards Homeplug dominate the market. In fact standards relate to for the moment only the interior installations and which is not interopérable with the existing external solutions to date.

HomePlug alliance currently works on the development of an external solution. Other standards should be born under a few months or years.

The equipment marketed to date for the general public is based on technologies Homeplug or DS2, which is unfortunately incompatible between them.

In low flow, three different standards exist. In Europe, the standard EHS/Konnex defines the standard of communication transmission currents, the functions plug-and-play and the applicatives transport. With the the United States, the standards are Echelon and Cebus.

See too

Notes & references

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