Digital Satellite Broadcasting and HDTV Services in Japan Masafumi Saito Science and Technical Research Laboratories NHK (Japan Broadcasting Corporation) Contents Present situation of satellite broadcasting in Japan q ISDB-S transmission system l features l system configuration l service availability q HDTV services by ISDB-S l assessment results of picture quality q Conclusions q History of Satellite Broadcasting in Japan May 1984: NHK started experimental broadcasting using BS-2a. Jun. 1989: NHK started regular service(NTSC) and experimental HDTV broadcasting using BS-2b. Apr. 1991: BS-3 was in use. JSB started pay TV service. Mar. 1996: Number of households that receive satellite broadcasting exceeded 10 million. Aug. 1997: BS-3 was replaced by BS4-1. Mar. 2000: Number of households that receive satellite broadcasting reached 14 million. Dec. 2000: Launch of digital satellite broadcasting using ISDB-S. Outline Scenario for Digital Satellite Broadcasting BS3 A N A L O G BS4-I NHK-1 FM - NTSC NHK-2 FM - NTSC JSB FM - NTSC MUSE D I G I T A L SDTV x3 HDTV BS5 MUSE - HDTV BS4-II HDTV Simalcast channel Radio&Data Digital HDTV/SDTV HDTV Digital HDTV/SDTV Digital HDTV/SDTV Radio&Data 1991 1997 2000 2007 Year Features of ISDB-S q Large l transmission capacity two HDTV programs in one satellite channel q Hierarchical l minimum service available during heavy rain q Operational l l modulation flexibility mixed transmission of HDTV and SDTV independence between broadcasters who share one transponder q Extensibility l EPG, data broadcasting, downloading, etc. Summary of the system characteristics Modulation scheme Raised cosine roll-off factor Transmission symbol rate Video coding Audio coding FEC (Outer code) FEC (Inner code) Inner code ratio Transport Layer Packet size TC8PSK/QPSK/BPSK 0.35 ( square root) 28.86 Mbaud MPEG-2 MP@HL for 1080i MP@ML for 480i MP@H14 for 480p MPEG-2 AAC Reed-Solomon (204,188) Convolutional (constraint length k=7) 1/2 for BPSK 1/2, 2/3,3/4, 5/6, 7/8 for QPSK 2/3 for TC8PSK MPEG-2 systems 188 bytes RF Bandwidth 34.5 MHz Payload Bit Rate 52 Mbps (max.) Block Diagram of Channel Coding MPEG-TS #1 #2 .. . Control Data #1 #2 .. . Main signal Outer coding Frame structure Energy dispersal Interleave Energy dispersal TDM RS(204, 188) TMCC TMCC encoding Outer coding RS(64, 48) Convolutional Burst signal Auxiliary Information Additional encoding & channel coding Inner coding Energy dispersal Modulation Frame Structure and Transmission Signal Frame structure Input TSs 1 frame = 48 slots 204 bytes 188 bytes MPEG Packet #A MPEG sync MPEG Packet #B MPEG Packet #C service A (high layer) parity service B (high layer) parity service B (high layer) parity service C (high layer) parity ........ service A (low layer) parity service B (low layer) parity Transmission signal frame #8 TMCC TMCC slot #1 slot #1 1 super frame = 8 frames slot #1 slot #1 slot #1 frame #1 slot #1 slot #2 slot #1 slot #48 slot #48 Transmission and Multiplexing Configuration Control (TMCC) TMCC carries: l l l l l frame synchronization modulation scheme and coding rate applied to each slot TS identification for each slot emergency alert signal information about site-diversity operation, etc. TMCC is modulated with BPSK and coded with RS(64,48) TC8PSK NTSC audio collapse 98 0 0.2 0.5 99.9 99 0.1 BPSK (r=1/2) QPSK (r=1/2) 1 2 5 Location Location == Tokyo Tokyo Antenna Antenna == 45 45 cm cm 2 4 6 8 10 20 10 CNR (dB) 12 14 16 in worst month (hours) (% of hours in worst month) Service Availability 99.99 Cumulative Shut-off Hours Service Availability of 12GHz Satellite Broadcasting Example of Hierarchical Transmission SOMY BS HiVision TC8PSK reception ?? ?? ?? ?? ?? ?? ?? ?? ?? QPSK/BPSK reception Penetration of HDTV Receivers in Japan (x1,000) reached 1000 900 934,000 at Aug. 1998 800 700 657,000 at Aug. 1998 Wide Screen TV with MUSE/NTSC Converter 600 500 400 HDTV Receiver 300 200 100 0 1 2 3 4 5 6 7 8 1995 9 10 11 12 1 2 3 4 5 6 7 8 1996 9 10 11 12 1 2 3 4 5 6 7 8 1997 9 10 11 12 1 2 3 4 5 6 7 1998 Relationship between viewing distance and required number of scanning lines Change of popular size of TV monitors in Japan 12- inch BB && WW 1 4-inch ? ? ? ? ? ? ? ? ? ? 20-inch NN TT SSSS CC 1953? 29-inch NN TT SS CC 1960? NN TT SS CC ? ? ? ? ? ? ? 1980? 50-inch HH DD T VV 1990? ? ? ? Number of scanning lines 3 000 ??Line ?? ??structure ?? ?? ??invisible ?? ?? ?? ?? ? ? 2 000 ? ? 1 000 Line ?? ??structure ?? ?? ?? visible ?? ?? ?? ?? 0 0 1 2 3 4 5 6 ? ? ? ( (xラ picture ? ? ? height) ) Viewing distance 2000? BS? ? ? ? ? ? ? ? ?Popular ? = size ? ?has? become larger ?Viewing ? ? distance = 2 mremains ? ( ? ? ) unchanged (about 2m) HDTV is suitable for the digital age 0 (DSCQS%) Quality Degradation Subjective Assessment of HDTV Picture Quality 10 20 30 Original 22Mbps 40 50 A B C D 18Mbps 16Mbps E F G H J Test Sequence (coded by MP@HL) K Conclusions q ISDB by satellite starts in December 2000 q The ISDB-S system l large transmission capacity of 52 Mbps/ch z l robust transmission against heavy rain z l two HDTV programs can be transmitted multiple modulation schemes and hierarchical transmission high operational flexibility z independence between broadcasters who share one transponder q HDTV services in Japan l ISDB-S is expected to play a central roll on digital HDTV