1. Overview of Satellite DMB

2. Contents  Digital Broadcasting  Characteristics of DMB  Terrestrial DMB  Satellite DMB  Overview of System E  Interactive Services

3. Digital Broadcasting 의 종류  DTTB (Digital Television Terrestrial Broadcasting)  2001 년 4/4 분기 방송 시작 (ATSC)  DTTB 기술  DVB-T: 유럽식, COFDM 채용  ATSC: 미국식, Trellis Coded 8 level VSB 채용  ISDB-T: 일본식, BST (Band Segmented Transmission)-OFDM 채용  DVB-S (Digital Video Broadcasting - Satellite)  SkyLife (2002 년 3 월 방송 시작 )  Cable Digital Broadcasting  2003 년 3/4 분기 방송 시작 예정  Terrestrial DAB (Digital Audio Broadcasting)  2004 년 방송 시작 예정  Satellite DAB

4. What is DMB?  AM/FM 과 같은 Audio Broadcasting 의 digital 화를 위해 DAB 추 진  최근 압축기술의 발달로 DAB 에 multimedia 전송 가능  ITU 에서 audio 외 video, data 전송을 포함시킴으로써 DMB 라는 명칭이 이용  DMB 의 다른 이름  DAB (Digital Audio Broadcasting)  DAR (Digital Audio Radio)  DRB (Digital Radio Broadcasting)  DSB (Digital Sound Broadcasting)  DMB (Digital Multimedia Broadcasting)

5. Characteristics of DMB  고품질 보장 전송방식 (2 개 이상의 고품질 sound channel)  향후 50 년 수용 가능  Mobility  Data channel 지원  PAD (Program Associated Data) + NPAD (Non PAD)  High Efficiency & Capacity  위성 DMB 의 특징  New Media  Personalized  Mobility  Multimedia

6. 지상파 DMB 의 종류

7. 위성 DMB 의 종류

8. 위성 DMB 개요도

9. DMB source coding  지상파 DMB ( 국내 표준 )  video: H.264 (AVC, MPEG4 part10)  audio: MPEG4 BSAC  interactive service: MPEG4  위성 DMB ( 국내 표준 )  video: H.264  audio: MPEG2 AAC

10. System E  Introduction  System Overview  Physical Layer & Modulation  Modulation  Sequence  CDM channels  Channel Coding  Error Correcting Code  Interleaving  Pilot Channel  Service Multiplexing

11. - Introduction  System E (CDM system, JAPAN)  Rec. ITU-R BO.1130-4(Satellite) System E Recommended  Via satellite and complementary terrestrial channel repeater  Provide high quality audio & multimedia data  For vehicular, portable and fixed reception  Features  First digital sound system operating in 2630~2655MHz  MPEG-2 System architecture for flexible multiplexing, interoperability  MPEG-2 AAC for audio source coding  Vehicular reception is main target  Satellite signal in omni-directional single element antenna

12. - System Overview  The System is composition  Feeder-link earth station  Broadcasting satellite  Terrestrial gap-fillers  Receivers  Shadowing & blocking in 2.6G band  Bit wise (de)-interleaver  Rake receiver : in CDM(Code Division Multiplexing) System  Gap-fillers  Direct amplifying type : 500m long line of sight area  Frequency Conversion type: 11G  2.6G, 3km in radius  Spotlight type : where CDM & RAKE receiver cannot decode properly

13. System E Overview

14. - Physical Layer & Modulation  Frequency Band: 2630-2655MHz  Modulation  CDM(Code Division Multiplexing) both on satellite and gap-filler  I,Q data are spreaded by same Walshcode # and truncated M- sequence  Modulated into QPSK  one pilot channel + several broadcasting channel  Chip rate  16.384MHz, gain=64  Signature and Spreading sequence  Signature sequence : 64bit length Walsh code  Spreading sequence : 2048bit length truncated M sequence  Number of CDM channels  Maximally 64, because 64chip length Walsh codes.  In corroborative testing, 30 CDM channels was multiplexed.

15. Block Diagram of Broadcasting System Detailed Block Diagram of CDM MPEG2-TS

16. - Channel Coding  Error Correcting Code  Outer code : Reed-Solomon code  Inner code : K=7 convolution code, 1/2, 2/3, 3/4, 5/6, 7/8 for broadcasting channel, 1/2 for pilot channel  Interleaving  Byte wise interleaving  Btw outer coding and inner coding  Bit wise interleaving  After inner coding  Pilot channel  Functions  Transmit unique word for frame synchronization and Frame counter for super frame synchronization  Send pilot symbol  Control data to facilitate receiver function  An broadcasting channel with arbitrary puncturing rate can be synchronized in one super frame time because it is the LCM of any possible punctured rate of convolutional code.

17. -- Pilot Channel Frame and super frame in pilot channel

18. -- Pilot Channel  PS : Pilot Symbol  32bit length ‘1’, aid RAKE receiver function  Twice power of broadcasting channel  D2 : Frame Counter  Goes from 0h to 5h in every super frame transmission  D3 ~ D 50 : Control Data  control physical, lower and middle network layer of receiver  Payload data in #th CDM channel Control data  Interleaving mode : interleave size 지정  Puncturing process mode : convolution code 코드화율 지정 (1/2 ~ 7/8)  TS ID : 해당 Channel 이 전송할 Transport Stream 번호  PID (max)minimum : 해당 Channel 이 전송할 TS 패킷의 PID 최 ( 대 ) 소치 – 다른 채널에 동일한 PID 범위가 할당되었을 경우는 복수개의 채널이 묶여 TS 를 구성하고 있음을 나타낸다. ( 한 채널 당 236kbps when conv code rate is 1/2 )  Version number  D51: reserved

19. Data structure of pilot channel data(D 3 ~D 50 )

20. --Service Multiplexing  MPEG2 System for multiplexing  TS(Transmit Sequence) 로 복수개의 프로그램을 Multiplexing  Example of Broadcasting Channel Usage  CDM#0 : pilot channel  CDM#1 : 프로그램 배열 정보 (PAT, CAT, INT) 나 공통적인 관련정보 (ECM-S, EMM-S) 를 전송함. 전송효율을 높임  CDM#2 : channel  CDM#3 & 4 : 두개의 CDM 채널을 묶어 프로그램 데이터 전송  정보 전송 rate 가 236kbps 이상인 프로그램을 전송가능 CDM#1 CDM#2 CDM#3&4 CDM#29 PATCATNITEMM-SECM-S PMTAUDIO PMTAUDIOVIDEO PMTAUDIO PID=0x000~0x0ff PID=0x100~0x10f PID=0x110~0x11f PID=0x200~0x20f

21. Interactive Services  Interactive Broadcasting  Key feature of next generation broadcasting services  Hard to endow broadcasting systems with pure interactive functions  Interworking between Broadcasting and Mobile communications  Collaboration rather than Convergence  Broadcast Channel: unidirectional broadband broadcast channel  Interaction Channel: bi-directional interaction channel  return interaction path (return channel)  forward interaction path  Interaction protocols corresponding to PAD (undefined yet)

22. DMB 기반 Interactive System