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12th Conference & Exhibition of TV & Audio TechnologiesBudapest, 2nd May 2007

Transition to Terrestrial Digital Broadcasting in Slovakia.

Let’s Compare Our Experience!

Juraj Oravec

Research Institute of Posts & Telecommunications, Banská Bystrica, Slovakia

joravec@vus.sk

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Slovakia, similarly to other EU countries, positively responded to the invitation of the Council from 14th November 2005 on the acceleration the transition from analogue to digital broadcasting and still in 2005 declared the aim to switch off the analogue broadcasting in 2012 at the latest.

This declaration has had a significant impact on the progress in preparing of DVB-T implementation from the technical, legislative and managing point of view.

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I. Frequency planning

Transition to Terrestrial Digital Broadcasting

in Slovakia

Budapest, 2nd May 2007

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• Frequency planning for DVB-T started in 1999.

• Because of rather small size of Slovakia (e.g. from Poland to Hungary across Slovakia there is only 80 km) it is theoretically necessary to coordinate with 16 countries (AUT, BIH, BLR, CZE, D, HNG, HRV, I, LIE, POL, ROU, RUS, SUI, SVN, SRB, UKR).

• As a final basis for the further development digital TV broadcasting an allotment and assignment GE06 plan can be considered.

• This plan consists of: allotments for 7 layers in the UHF band (except of four allotment

areas where only six layers have been achieved), allotments for 1 layer in the VHF band, 438 assignments; approximately 70 SVK assignments have been

put to the pending list as a matter of further negotiations with Hungary.

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Fig. 1 – Names and shapes of the SVK allotment areas in the UHF band

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Allotment plan for Slovakia (according to GE06)

Note: Channels in different allotment areas highlighted by colour must work as an one SFN.

* allotment is missing, bur several assignments using Ch40 exist

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Fig. 2 – Layer 1 (UHF)

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Fig. 3 – Layer 2 (UHF)

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Fig. 4 – Layer 3 (UHF)

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Fig. 5 – Layer 4 (UHF)

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Fig. 6 – Layer 5 (UHF)

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Fig. 7 – Layer 6 (UHF)

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Fig. 8 – Layer 7 (UHF)

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Fig. 9 – Layer 8 (VHF)

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II. Legislation

Transition to Terrestrial Digital Broadcasting

in Slovakia

Budapest, 2nd May 2007

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Four bodies are active in the field of the digital broadcasting (except of Parliament and Government):

Ministry of Culture,

Ministry of Transport, Posts and Telecommunications,

Telecommunications Office,

Council for Broadcasting and Retransmission.

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For the time being six fundamental documents exist:

Act on Electronic Communications Nr. 610/2005 Coll. 

National Policy for Electronic Communications approved by the Governmental Resolution Nr. 196/2003 (19th March 2003)

Policy on Frequency Spectrum Utilisation for Broadband Access approved by the Governmental Resolution Nr. 5/2006 (11 th Jan. 2006)

Program Declaration of the Slovak Government approved by the Governmental Resolution Nr. 660/2006 (31st July 2006)

Strategy on Transition from Analogue to Digital Terrestrial TV Broadcasting in Slovakia approved by the Governmental Resolution Nr. 646/2006 (26th July 2006)

Law on Digital Broadcasting of Program Services and on Providing Other Content Services by Means of Digital Transmission and on Modification of Some Laws (also called “Digital Law”) approved by the Parliament on 29th March 2007

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Digital Law

• This Law will come into force on 31st May 2007.

• It deals with all kinds of TV & radio broadcasting (DVB-T, DVB-H, DVB-S, T-DAB, DRM, ...).

• Comparing with existing “analogue” broadcasting, as a main difference the strict separation of content and technical regulation can be considered.

• The content regulation keeps in hands of the Council for Broadcasting & Retransmission,

• For the technical regulation the Telecommunications Office will be fully responsible.

• To operate the digital broadcasting, i.e. to use frequencies, will be possible only on the basis of so called “terrestrial operation permission”.

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• The final “Parliamentary” version of the Law underwent many changes in comparison with the Governmental draft. These changes can be considered as a result of intensive lobbing of broadcasters.

• Generally it is expected that the transition will not be a simple process. That’s why several Articles deals with conditions of transition.

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According to Article 67 the Telecommunications Office will have to publish the generally binding directive in which e.g. time schedule and allotment plan for the “public layer” (i.e. public multiplex) will be specified (Parliamentary draft was talking about three layers).

• As a deadline for providing the public multiplex the year 2012 was specified.

• Before this year it is expected that all existing “analogue” broadcasters will share one frequency layer.

• This layer should come into operation not later than in 2011.

• In the Parliamentary draft it was proposed that in 2011 already three multiplexes would be available.

• In the final version of the Law, existing broadcasters succeeded to eliminate potential competitors for next four years.

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• The public broadcaster is preferentially allowed to apply for datastream for two programs. Of course, he can apply for more programs if there is a space enough in a multiplex.

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Article 68:

Not earlier than 30 days after the Directive of the Telecommunications Office comes into force, it is possible to start the first call for tender for the terrestrial operation permission.

    Article 69 – deals with taking the “analogue” frequencies back:

• If the Telecommunications Office assigns the terrestrial operation permission with allotment frequency being used by an “analogue” broadcaster, the Council must decide in 90 days about taking back this frequency.

• The Council must decide about taking back all other frequencies used by “analogue” broadcaster if they cover the relevant allotment area.

• Formerly this Article also contained the paragraph that the simulcasting cannot last longer than six month. From the final version of the Law this paragraph disappeared.

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     Article 71:

• Public TV broadcaster must apply for at least two TV licences with national coverage not later than three month after this Law comes into force.

• Public radio broadcaster must apply for at least one radio licence with national coverage not later than three month after this Law comes into force.

     Article 27:

• Licence for digital broadcasting is assigned for the unlimited time.

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According to Article 9 „the multiplex provider is competent to decide about programs in the multiplex”.

• It means that the content in the multiplex fully depends on the agreement between broadcaster and network operator.

Special Chapter deals with local broadcasting.

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III. Practical Experience from the Digital Broadcasting Trials

Transition to Terrestrial Digital Broadcasting

in Slovakia

Budapest, 2nd May 2007

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For the time being the DVB-T broadcasting in Slovakia is in the stage of pilot projects. The first pilot project was put into operation in October 2004. These projects work in three areas:

• in the eastern Slovakia in the area of the city Košice and the town Prešov on the channel Ch44 – four TV programs. Basic parameters: ERPmax 2x5.1 kW, modulation 64-QAM, code rate 2/3,

guard interval D/Tu = 1/8;

• in the central Slovakia in the area of towns Banská Bystrica and Zvolen on the channel Ch59 – five TV a seven R programs. Basic parameters: ERPmax 2x10 kW, modulation 64-QAM, code rate 2/3, guard interval D/Tu = 1/8. The main purpose of this project is to test DVB-T characteristics in the mountainous area;

• in the western Slovakia in the area of the Bratislava city and the town Malacky on the channel Ch66 – four TV a four R program. Basic parameters: ERPmax 1 + 3.6 + 0.2 kW, modulation 64-QAM, code rate 2/3, guard interval D/Tu = ¼. The main purpose of this project is to test DVB-T characteristics in the dense and miscellaneous urban built-up area.

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Coverage of pilot projects areas

KE - PO

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BB - ZV

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BL - MA

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Network operators:

• Telecom Corp. Ltd. (KE, PO)

• TBDS Inc.(former Slovak Telecom, Inc. – Radiocommunications – until end of April 2007)

Operators test various technologies and acquire practice in building, operation and measurements.

They cooperate with the Research Institute of Posts & Telecommunications, in particular in the field of the coverage assessment and assessment of methods of measurements.

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The most important information from measurements:

a) The actual coverage is smaller than calculated. In the area of Banská Bystrica only 67 % conformity was achieved; in the Košice area the conformity has been 83 %.

Worse results were achieved in the mountainous areas.

It is supposed that this disproportion has been caused by

• rather strict selection of measurement places (chosen in expected critical places),

• morphology and,

• “rough” scale of DTM (100 x 100 m) which does not allow to simulate the homogeneity of the electromagnetic field.

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b) Except of the field strength it is also necessary to evaluate other parameters of the digital signal, especially MER. Its values vary smoother (approx. linearly) what is not valid for BER. It was determined that for trouble-free digital reception it was necessary to achieve :

• for the variant C2 (modulation 64-QAM): MER 22 dB,

• for the variant B2 (modulation 16-QAM): MER 17 dB.

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c) Although the distance between SFN transmitters in Banská Bystrica and Zvolen is only 20 km, which is less than the distance corresponding to the guard interval 1/8, i.e. 112 s (corresponds to 33 km), also places with the delay more than 112 s were found.

It was identified that there are reflected signals from the surrounding mountains; the levels of wanted and unwanted signals were approximately equal. Intersymbol interference (ISI) and considerable degradation of the signal quality (specified by MER) was identified.

From that reason in mountainous areas it is recommended to use a longer guard interval or to increase the signal level by means of gap-fillers.

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d) The comparison of C2 and B2 variants showed that by using the B2 variant it was possible to improve the coverage significantly. It corresponds to the theory – for B2 variant 6 dB lower field strength is required comparing with C2.

This fact enables to eliminate the coverage loss referred in point a).

The practice also showed that the variant B2 is less sensitive to the man-made noise.

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e) When testing the indoor reception it was established that due to inhomogeneity of the field in rooms as well as the influence of surrounding buildings it is appropriate to use the active antennas.

These antennas should be omnidirectional as in case of DVB-T the reflected signals can be considered as wanted ones.

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e) Because of permitted speed, the mobile reception was tested especially on the motorway between Banská Bystrica and Zvolen. It was found out:

    by the non-diversity reception:

  by the modulation 64-QAM (variant C2):

• Although the theoretical maximum speed is 25 kmph, the mobile reception was practically possible up to the speed 30 - 35 kmph, sometime also more. However, in some parts of the route there were point where the reception was not possible by the speed lower than 25 kmph either – some drop-outs appeared.

   by the modulation 16-QAM (variant B2):

• Although the theoretical maximum speed is 49 kmph, in an approx. 1 km long path the reception was perfect by the speed 60 kmph.

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     by the diversity reception :

  by the modulation 64-QAM (variant C2):

• Although the theoretical maximum speed is 57 kmph, the mobile reception was possible by the speed 140 kmph. In places with approximately equal signal level (in the range of 5 dB) from both SFN transmitters some drop-outs appeared. In spite of the 20 km distance between transmitters, some signals corresponding to the distance 44 km were identified..

  by the modulation 16-QAM (variant B2):

• Although the theoretical maximum speed is 57 kmph, the mobile reception was possible by the speed 160 kmph. The producer of the applied STB declares that by the variant B2 the reception is possible up to the speed 200 km/h. Again, in places with approximately equal signal level from both SFN transmitters some drop-outs appeared.

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Practical experience has resulted in elaborating the drafts of two documents:

• Technical Directive on Measurement and Assessment of the Coverage of the Slovak Republic by the DVB-T Signal,

• Technical Specification of DVB-T Receivers Intended to Be Put to the Slovak Market.

These drafts are ready to be presented to the public discussion, first in the Technical Section of the SKDV group.

(supports Slovak DVB-T)

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IV. Conclusion

Transition to Terrestrial Digital Broadcasting

in Slovakia

Budapest, 2nd May 2007

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• Although according to the Strategy approved by the Government the test transmission (pilot projects) should have stayed in operation until end of June 2007, the Digital Law have fixed that the individual licences for such broadcasting are prolonged until end of 2007.

• That’s why it is probable that the regular transmission will start in January 2008.

• It can be noted that due to the force of EU bodies on the progress in DVB-T implementation also Slovakia pays increased attention to this matter.

• The time available is rather short, in particular if we realize that it is necessary to build about 68 high power transmitters and about 600 gap-fillers. Every shift of the regular transmission means the shortening of this time.

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• In the whole process of the transition from analogue to digital broadcasting the Group for Digital Broadcasting (Skupina pre digitálne vysielanie - SKDV) is very active.

• It consists of three sections: Technical, Legislative and Section for Information and Economy.