CEPT Activities on Radio Services Compatibility with Power Line Telecommunications

1. CEPT ERC SE35 activities on compatibility between radio services and PLT (Power Line Telecommunications) Dubrovnik, 6-7 March 2001 Bernard Després Chairman CEPT SE35

2. History of the work in CEPT -1 • In 1999, the UK administration presented in CEPT ERC Working Group Spectrum Engineering (WG SE) papers on the Power Line Telecommunication (PLT) trials in the Manchester area and on the potential disturbances induced into radio services • May 1999, a PLT correspondence group was established within WG SE • A questionnaire on the PLT National regulations and on the appropriate way to regulate such systems was prepared in Summer 1999 and sent to CEPT administrations participating in WG SE. • 10 answers were received and a compilation was prepared. • In the course of this work, the idea was expressed to also address other types of cable transmission systems like xDSL and cable TV

3. History of the work in CEPT -2 • A special meeting on PLT was organised in Mainz on December 6-7, 1999. • Conclusion from the Mainz meeting : The group recommends to WG SE to create a Project Team on Power Line Telecommunications (PLT) and cable transmissions in general. • February 2000 : at the CEPT ERC WG SE meeting in Naples, the proposal was endorsed and it was decided to establish a new Project Team SE35 entitled : • Power Line Telecommunications (PLT) and cable transmissions in general

4. SE35 terms of reference • Extracts from the approved SE35 terms of reference : • identify the frequency ranges over which PLT and cable transmission are likely to operate now and for the future ; • identify those services that are likely to be affected by PLT and cable transmissions in general (broadcasting, maritime, radionavigation, radioamateurs…) and evaluate their protection needs ; • investigate methods of measuring the emissions from PLT and cable transmissions ; • perform compatibility studies to derive limiting values for emissions from PLT and cable transmissions to protect primary services ; • propose a harmonised European approach for PLT systems and cable transmissions in general ; • produce a report covering the various aspects for wide consultation within Europe ; • in the course of these studies, liaise closely with the relevant EMC standardisation committees and with ITU-R WP 1A and 1C.

5. SE35 activities • Since the creation of the group, four meetings have been held with an average participation of 25 people from 10 CEPT administrations and from the industry • Work has progressed towards the preparation of an ERC report on « PLT, cable transmission in general and their effects on radiocommunication services » • Liaison statements have been sent and received from several CEPT and ETSI standardisation groups • Information has been gathered on the characteristics of radio services to be protected (frequency band, sensitivity, protection ratio…) in the frequency ranges where cable signals run (1-30 MHz for PLT) • The ERO and WG FM have made a review and will produce a report on the use of the HF band throughout CEPT

6. 80 70 60 NB30_3m T5MSWQ_on in dBµV/m E in dB(µV/m) 50 T5MSWQ_off in dBµV/m T5MS_on in dBµV/m 40 30 20 0 1000 2000 3000 4000 5000 6000 frequency (kHz) Field trial results in Germany-1 • Field strength measured outside the building at 5 meters from the injection point (transformer room), compared with the proposed German NB30 limit (red line, the limit is defined at 3 meters) ; the PLT injected level is +17 dBm and ranges from 2 to 3 MHz

7. In both trials, when the injected PLT signal exceeds 10 dBm, the result exceeds NB30 But, if lower injection levels are used, the radiation level is around the NB 30 level Field trial results in Germany-2 • Field strength measured at 3 meters outside a house (this experiment combined both access and in-House PLT) compared with the proposed German NB30 limit (red line) ; the PLT injected level is +10 dBm and ranges from 1.5 to 3.5 MHz

8. Field trials in Norway • Two pilot-projects took place in Norway in two different cities with two different PLT manufacturers • Maximum field strength measured at 3 meters range from 45 to 65 dBµV/m (as a comparison, the proposed German NB30 limit range from 30 to 40 dBµV/m) • Listening tests with a shortwave radio receiver showed that radiation from the powerline systems gave an embarrassing noise in the frequency corresponding to the PLT wanted signals • Audible interference up to 350 meters from the line in some cases

9. Other SE35 results • A measurement procedure based on two initial proposals made by the UK and German administrations have been elaborated. It explains the procedure to measure radiated field around cable transmission installations • Theoretical calculations on the cumulative effect of a large number of PLT or cable transmission installations have been presented • Results of an extensive study involving measurements and calculations made in Switzerland on the far field behaviour of electricity lines have also been presented • The PLC Forum presented K factor values (ratio between the injected power fed into the cable and the resulting radiated field at a given distance) measured over a very large number of PLT installations • All these elements will be incorporated into the ERC report in preparation

10. Latest developments in CEPT • WG FM (Frequency Management) February 2001 meeting : • Extract from an approved liaison statement to ETSI on PLT : • During the meeting of WG FM many administrations expressed serious doubts about the possibility to allocate spectrum to PLT applications based on the current regulations and definitions in the Radio Regulations such due to the fact that PLT applications cannot be considered as a radio service. These doubts relate to the possibility of changing the Radio Regulations to the benefit of systems like PLT at a future competent WRC. • WG SE (Spectrum Engineering) February 2001 meeting : • WG SE instructed SE35 to prepare an ERC Recommendation which should define generic flat or slowly varying limits (likely to be based on the German and UK limits) for any PLT and cable transmission installation

11. Conclusions : SE35 future activities on PLT • The work continues towards the preparation of an ERC report on PLT, cable transmission in general and their effects on radiocommunication services : the aim is to produce a first consolidated draft to be presented at the WG SE meeting in May 2001 • Work will start towards the preparation of an ERC Recommendation proposing some limits to be applied to PLT and similar cable transmission systems : the agreed time scale is to try to have it finalised for the WG SE October meeting • In the course of these activities, close liaison with the relevant standardisation bodies (CENELEC, ETSI…) will be maintained