Digital Radio Mondiale

Transcription

1 Digital Radio Mondiale Before its Trade Launch in June 2003 Andy Giefer BBC World Service

2 Overview DRM Recording & Editing Distribution Transmission Monitoring Do-it-yourself DRM

3

4 At a Glance Digital Radio System for LF, MF, HF Improved Audio Quality Better Usability

5 Timeline 1998 Consortium founded 2000 Field trials start 2001 ITU recommendation & ETSI standard 2003 IEC Standard 2003 Launch at WRC in June 2004 First consumer receivers 2005/2006 Mass-market cheap receivers

6 What have we learned?

7 II: Recording & Editing

8 Recording often uses compression Minidisk, MP3 recorder Non-linear editing often uses compression Minimise effects of cascaded audio coding Use low compression, e.g. 384 kbit/s

9 III: Distribution

10 Encoding and mutliplexing Where should the programme be encoded? Sat Studio TX Site

11 Encoding and mutliplexing At the Studio? Sat Studio TX Site DRM Mux

12 Encoding and mutliplexing Or at the Transmission Site? Sat Studio TX Site DRM Mux

13 At Studio Output Use Multiplex Distribution Interface (MDI) Includes audio and modulator information kbit/s per stream One stream per modulator setting

14 At Transmission Site Cascaded coding requires low compression Codec MPEG layer-2 MPEG layer-3 MPEG-4 AAC aacplus Mono Bitrates kbit/s kbit/s kbit/s kbit/s

15 Which method? Central factors Modulator settings used at Tx sites Determines satellite capacity Feed used for other delivery systems? Synchronised networks used?

16 IV: Transmission

17 Modulator Settings Pure DRM or DRM in simulcast HF bandwidths: 4.5, 9, 10, 18 and 20 khz Robustness modes A, B, C, D 6 code rate/constellation combinations

18 Modulator Settings Pure DRM or DRM in simulcast HF bandwidths: 4.5, 9, 10, 18 and 20 khz Robustness modes A, B, C, D 6 code rate/constellation combinations

19 SSB DRM 9/10 khz

20 AM DRM 13.5/15 khz

21 AM DRM 18/20 khz

22 DRM 18/20 khz

23 Modulator Settings Pure DRM or DRM in simulcast HF bandwidths: 4.5, 9, 10, 18 and 20 khz Robustness modes A, B, C, D 6 code rate/constellation combinations

24 Mode A B C D Robustness Application Medium-wave Short-wave Doppler HF Tropical HF

25 Modulator Settings Pure DRM or DRM in simulcast HF bandwidths: 4.5, 9, 10, 18 and 20 khz Robustness modes A, B, C, D 6 code rate/constellation combinations

26 64-QAM 16-QAM B/10k A/9k A/20k Bit rates in kb/s

27 64-QAM 16-QAM B/10k A/9k A/20k AAC or CELP Mono

28 64-QAM 16-QAM B/10k A/9k A/20k aacplus Mono AAC or CELP Mono

29 64-QAM 16-QAM B/10k A/9k A/20k aacplus Pseudo Stereo aacplus Mono AAC or CELP Mono

30 64-QAM 16-QAM B/10k A/9k A/20k aacplus Stereo aacplus Pseudo Stereo aacplus Mono AAC or CELP Mono

31 Networks Single-Frequency-Networks Reduce risk of flat fading Multiple-Frequency-Networks Use frequency diversity Receivers switch frequency automatically Increase signal reliability!

32 V: Monitoring

33 Automatic monitoring possible (unlike AM) Estimate Signal strength Signal-to-Noise Ratio Doppler & delay spread Audio quality: %-age correct audio frames Try to reduce information for overviews Feedback to set modulator dynamically?

34

35 16 Monitoring receivers in Europe Send daily data files Central database sends daily text summaries Started in April 2002

36 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC BBC DW NOR RNW ULM Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*`

37 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC BBC DW NOR RNW ULM Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*`

38 64-QAM 16-QAM B/10k A/9k A/20k aacplus Mono AAC or CELP Mono

39 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC BBC DW NOR RNW ULM Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*`

40 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC BBC DW BBC NOR RNW ULM BBC Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 RxName DW NOR5 9.0 RNW ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ULM ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*` Quality[%] Slot

41 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC BBC DW NOR RNW ULM Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*`

42 Daily Report :00-15: Mode:B MSC:64 SDC:4 Prot:A0/B bps 5875 khz "BBCWorld Service RxName Quality[%] AudioQ>0%: MER AudioQ=100%: MER Signal [dbuv] Delay90[ms] Doppler[Hz] Slot Audio 10% [db] 10% Med 90% [db] 10% Med 90% 10% Med 90% 10% Med 90% BBC1 BBC3 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` BBC BBC3 DW ````````````````````````````````````1```````*11*`*```1**` DW NOR _-_--_ RNW3 ****````*````*``****`````***```````*```*``*`**`******`*`` ULM ULM1 `*``*``````````````````````````````````````````````````*` Evolution of Audio Quality Q in 1-Minute Steps. L is the accumulated dropout length in seconds. 0%<=Q<10%: _ 10%<=Q<90%: - Q=100%: ` 5<L<=6: 5 4<L<=5: 4 3<L<=4: 3 2<L<=3: 2 1<L<=2: 1 0<L<1: * BBC1 BBC3 DW1 NOR5 RNW3 ULM1 ````````````````````````````````````````````````````````` ````````````````````````````````````````````````````````` ````````````````````````````````````1```````*11*`*```1**` _-_--_ ****````*````*``****`````***```````*```*``*`**`******`*`` `*``*``````````````````````````````````````````````````*`

43 VI: Do-it-yourself DRM

44 Software Receivers Open-source DRM receiver TU Darmstadt Official DRM Software Radio Build your own receiver

45 Use HAM radio receivers!

46 Record data and give feedback

47 Schedule on

48 VII: Summary

49 Recording & Editing Use low compression: 384 kb/s Distribution Encode at Studio or at Tx Site Central multiplexer for SFN/MFN Transmission Simulcast, Mod. settings

50 Monitoring Automatic processing of a wealth of data Possible feedback to modulator Do-it-yourself DRM Downlaod software receiver Build your own DRM system

51

52 The End