First results on compatibility planning of DRM+ and HD Radio in the VHF band

Transcription

1 9th Workshop Digital Broadcasting FhG IIS Erlangen Leaving the dead-end street: New ways to digitise the VHF- sound broadcasting with DRM Part II: First results on compatibility planning of DRM and HD Radio in the VHF band Dipl.-Ing. Joachim Lehnert (Landeszentrale für Medien und Kommunikation Rheinland-Pfalz) First results on compatibility planning of DRM and HD Radio Outline First results on compatibility planning of DRM and HD Radio in the VHF band Principles of frequency planning in VHF Band Frequency planning with HD Radio 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert

2 Principles of VHF frequency planning Principles of frequency planning from the beginning of broadcasting on TX Universe TX planning according to Final Acts RRC 84 f VHF /P wanted ITU-R P.546-: Propagation Predictions ITU-R BS.42-9: Planning Standards E min [dbµvm] Protection Ratios f VHF /P i RX Universe ITU-R BS.704: Reference Receiver ITU-R BS.45-2: Low-cost Receiver ITU-R BS.64: Determination of Protection Ratios (PR) under laboratory conditions with reference receiver (~ 9-970) degradation of audio-snr from 56 to 50 db (this is not a audible distorsion!) 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Principles of VHF frequency planning Principle of VHF frequency planning st: Calculation without new TX: Determination of the interference conture (wanted field strength = usable field strength ) 2nd: Calculation with new TX : Calculation of usable field strength with new TX at the interference conture and at TX site : m i i U, before = ( Ei,% PR f i= E wanted, 50% = E U, before i E [ G ]) m U, new = i,% f i= i i E ( E PR [ G TX planning Criterion: new TX interferes if: EU, new > EU, before 0. 5dB E i E ]) E i E i E wanted E i E i coverage is limited by interferences E min 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 2

3 Principles of VHF frequency planning Frequency and network planning software FRANSY Computer based frequency analyses with frequency and network planning software FRANSY (modified for calculations with HD Radio und DRM) and ITU-R BS.42-9 as basis Interference analysis to indentify the impact of the new TX planning onto existing services according to the ITU recommendations Compatibility analysis to indentify the constraints for the new TX to protect existing services based on the so called Administrative Proceeding of Potentially Concernment of the German BNetzA transmission caracteristics of new TX, esp. radiation pattern Coverage analysis to indentify the sevice area of new TX according to the ITU recommendations 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Principles of VHF frequency planning Analysed VHF TXs VHF TXs which serve Kaiserslautern SWR / 90.8 MHz / 25 kw SWR2 / 93.9 MHz / 25 kw SWR3 / 97.5 MHz / 25 kw SWR4 / 99.6 MHz / 0.5 kw RPR / 03. MHz / 25 kw Big / 07.6 MHz / 25 kw Bornberg Donnersberg SWR / 99. MHz / kw SWR2 / 92.0 MHz / kw SWR3 / 0. MHz / kw SWR4 / 05.6 MHz / kw KL/Vogelweh AFN / 00.2 MHz / 7 kw KL/Dansenberg Antenne KL / 96.9 MHz / 0.5 kw DR-DLF / 05. MHz / 0.2 kw DR-Kultur / 98. MHz / 0.6 kw Map by: German Bundesamt für Kartographie und Geodäsie 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 3

4 Outline First results on compatibility planning of DRM and HD Radio First results on compatibility planning of DRM and HD Radio in the VHF band Principles of frequency planning in VHF Band Frequency planning with HD Radio 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Protection ratios for the analyses with DRM PR [db] Protection ratio for interfered with by DRM based on the results of the laboratory measurements and the field trial in 2007/08 and on ITU-R BS.42-9 and ITU-R BS db interferes DRM interferes PR [db] Protection ratio for DRM interfered with by based on latest studies in QAM 4QAM -9 db -29 db interferes interferes DRM (6QAM) interferes DRM (4QAM) khz 0 khz frequency offset [khz] frequency offset [khz] 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 4

5 First results of compatibility analyses for DRM Kaiserslautern Bornberg Donnersberg f [MHz] P [kw] P DRM - [db] db = These results suggest that in general, a existing TX can replaced by a DRM TX by lowering the ERP by 5 db to protect existing services 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Example of coverage analysis for converting a TX from to DRM with 5 db = Coverage area of the TX Kaiserslautern Dansenberg 96.9 MHz (Antenne KL) / 0.5 kw E min = 54 dbµv/m DRM 6QAM / 0.6 kw E mindrm = 25 dbµv/m DRM 4QAM / 0.6 kw E mindrm = 5 dbµv/m KL/Dansenberg Coverage according to ITUR BS.42-9 (aerial G=6 db. 0m) considering the 20 strongest interferers Map by: German Bundesamt für Kartographie und Geodäsie 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 5

6 First results of coverage analyses for DRM with - 5 db = Coverage < Coverage Map by: German Bundesamt für Kartographie und Geodäsie This output and the other coverage analysis results suggest that the coverage of a DRM TX is better than before with the TX, in spite of the power reduction of 5 db (This effect stems from the low protection ratio for into DRM, yielding a low value of the usable field strength, and, therefore, a low interference impact), coverage reserve of a DRM TX within the service area is higher than those of the former TX, DRM coverage area using 4QAM is larger than using 6QAM. 9th Workshop Digital Broadcasting September, , Erlangen - - Joachim Lehnert Problem to switch over a TX to DRM problem! No broadcaster will turn off his TX to realize a DRM transmission for the simple reason that he would loose all his listeners, esp. in the early stage of digitisation. 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 6

7 First results on compatibility planning of DRM and HD Radio Outline First results on compatibility planning of DRM and HD Radio in the VHF band Principles of frequency planning in VHF Band Frequency planning with HD Radio 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Frequency planning with HD Radio Protection ratios for the analyses with HD Radio Protection ratio for interfered with by HD Radio based on the results of the laboratory measurements and the field trial in 2007/08 and on ITU-R BS.42-9 and ITU-R BS.64-2 PR [db] 8 db ETSI EN violates the European spectrum mask! interferes HD Radio interferes The protection ratio for HD Radio interfered with by is still not determined, so no coverage analsyses could be made khz frequency offset [khz] 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 7

8 Frequency planning with HD Radio First results of compatibility analyses for HD Radio Hybrid Mode Kaiserslautern Bornberg Donnersberg f [MHz] P [kw] P HD Radio - [db] X {0 7} db = These results suggest that the use of HD Radio Hybrid Mode with a low power TX (less than kw) is sporadically possible without any power reduction, but in all other cases only possible with power reductions up to 7 db and thus with loss of existing coverage, with a mid power and high power TX is only possible with power reductions up to 7 db due to the high interference in the 200 khz adjacent channel and thus with loss of existing coverage, is not possible above 07.5 MHz due to increasing interference into aeronautical radio navigation services located on the frequency range above 08 MHz. 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Frequency planning with HD Radio Problem to use HD Radio Hybrid Mode Problem! No broadcaster will broadcast simulcast and HD Radio when he has to reduce his TX power for the simple reason that he would loose most of his listeners. 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 8

9 Outline First results on compatibility planning of DRM and HD Radio First results on compatibility planning of DRM and HD Radio in the VHF band Principles of frequency planning in VHF Band Frequency planning with HD Radio 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Proposal for conditions of DRM Hybrid Mode DRM Hybrid Mode: = STUDIO DRM-Hybrid-Mode = Simulcast of and DRM with following conditions: broadcasting both signals over the same TX and antenna power remains unchanged and so the service area remains the same receiving both signals in the same service area the well known broadcasting frequency will be used furthermore receivable with a one frontend VHF /DRM combined receiver with an automatic analogue/digial switchover important due to economical considerations particular at the beginning of VHF digitisation 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 9

10 Proposal for parameters of DRM Hybrid Mode ERP { } khz {0-50} db frequency offset [khz] f ( DRM) DRM TX power remains unchanged flexible frequency offset: ± [200 khz khz], f = 50 khz planning DRM in that channel with the lowest interference impact 4QAM modulation flexible TX power as high as compatible to existing services 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert f [MHz] P [kw] f DRM - [MHz] P DRM - [db] P DRM [W] First results of compatibility analyses for DRM Hybrid Mode Kaiserslautern The results propose that Bornberg Donnersberg the determined TX power reductions of the DRM Hybrid signal are in the lower watt range (similar to the digital part of a HD Radio Hybrid signal), in some cases, a quite high DRM signal power can be reached, the required power reduction is obviously not as high for low power TXs as for high power TXs th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 0

11 Example of coverage analysis for DRM Hybrid Mode Coverage area of the TX Kaiserslautern Dansenberg 96.9 MHz (Antenne KL) / 500 W (0 db) E min = 54 dbµv/m DRM 4QAM / W (-5 db) E mindrm = 5 dbµv/m DRM 4QAM / 5 W (-20 db) E mindrm = 5 dbµv/m DRM 4QAM / 0.05 W (-40 db) E mindrm = 5 dbµv/m Coverage according to ITUR BS.42-9 (aerial G=6 db. 0m) considering the 20 strongest interferers KL/Dansenberg Map by: German Bundesamt für Kartographie und Geodäsie 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert First results of coverage analyses for DRM Hybrid Mode Coverage <? > Coverage Map by: German Bundesamt für Kartographie und Geodäsie This output and the other coverage analysis results propose that the DRM coverage with 4QAM is still greater as the existing coverage if the DRM power reduction is higher than 20 db (which is a similar power difference as for a HD Radio Hybrid signal), but is smaller than the coverage with a power reduction of 40 db or more. 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert

12 Problem to deploy DRM Hybrid Mode Problem! The DRM Hybrid Mode gives a chance for local or regional coverage areas but is currently not more than just a good idea. Investigations are pending *). Concepts for TX and RX have still to be developed. *) first compatible tests had been conducted by University of Hannover in August th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Outline First results on compatibility planning of DRM and HD Radio First results on compatibility planning of DRM and HD Radio in the VHF band Principles of frequency planning in VHF Band Frequency planning with HD Radio 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 2

13 ITU planning recommendations as barriers ITU-R BS.42-9 ITU-R BS.64 no turnaround! On the basis of the ITU planning recommendations for VHF systems the introduction of a new OFDM TX into the existing VHF environment involves high or even insurmountable barriers this is a dead-end street! HD Radio can generally only be planned with loss of existing coverage DRM can only be planned with high coverage if the existing TX is replaced with DRM DRM Hybrid Mode gives a chance for local or regional coverage areas, but this mode has still to be developed 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert Gap between interferences in TX planning and RX reality turn? BUT: Experiences from the field trails with HD Radio and DRM and from daily receiving say: The determined interferences based on the ITU Recs. have not (or less) been noticed in reality! Why is there this difference? 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 3

14 Gap between coverage and receiving area TX Universe ITU-R BS.704: reference receiver Technology of the 970th/ fixed RX 9-70 ITU-R BS.64: Determination of Protection Ratios Drop of SNR from 56 db to 50dB (not audible) Final Acts RRC-84 ITU-R BS.42-9: Planning standards Definition: coverage The calculated interferences to protect existing TX based on ITU-Rec. have not (or less) been noticed in reality because... RX: better selectivity & mobil/portable RX RX Universe Optimod: SNR ~40dB = 2008 Definition: receiving area 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert First step for the digitisation of the VHF Band Free passage! Out of the dead-end street with a fair solution for everybody!!! (for the existing broadcaster and the future digital network operators): Adjustment of the ITU planning recommendations for the VHF band et al. so that today s real receiving world is reflected properly also taking into account mobile and portable reception -, i.e. that planned and real world no longer diverge. 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 4

15 Adjustment of ITU recommendations ITU-R BS.704: reference receiver Adjustment of the reference receiver parameters to the today state of the art Amplification to specify the different receiving scenarios Supplement of digital reference receivers ITU-R BS.64: Determination of Protection Ratios Supplement to identify interferences from and onto digital broadcasting systems Modification of the measurement method from SNR to a criterion which refers to perceptible audible distortion: i.e. SINAD ITU-R BS.42-9: Planning standards Revised protection ratios based on a new measurement method (SINAD) with new reference receivers (modifed ITU-R BS.64). Supplement of protection criterions between analogue and digital TX and digital-digital ITU-R BS.4-5: Systems for digital sound broadcasting in MHz Supplement of DRM with the Mode E (DRM) ITU-R SM.40: Test Procedures for Aeronautical Receiver in 08-8 MHz Supplement of compatibility criterions for digital VHF systems 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert On the way to the digitisation of VHF band There are a lot of construction sites on the roadmap to digitise the VHF band in Europe (with DRM as favorite) in 2020 et seq.? Engineering Regulations Market first and at once! directliy after! directly in connection with! 45(08) : Initial Draft for an ECC Report Future Possibilities for the Digitalisation of Band II 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 5

16 First results on compatibility planning of DRM and HD Radio a bundle of questions Thank you for your attention further information on 9th Workshop Digital Broadcasting September, , Erlangen Joachim Lehnert 6