Digital Video Broadcasting Final Custom Implementation DSP Course Alireza Mazraee Farahani Spring 2010 Class presentation for the course: “Custom Implementation of DSP Systems” All the materials are copy rights of their respective authors as listed in references.
DVB Overview • DVB Project is an industry-led consortium of over 300 companies • The DVB Project was launched on 10th September, 1993 • In 1995 it was basically finished and became operational • There are several sub-standards of the DVB standard • DVB-S (Satellite) – using QPSK – 40 Mb/s • DVB-T (Terrestrial) – using QAM – 50 Mb/s • DVB-C (Cable) – using OFDM – 24 Mb/s • These three sub-standards basically differ only in the specifications to the physical representation, modulation, transmission and reception of the signal
DVB Overview (Cont.) • The DVB stream consists of a series of fixed length packets which make up a Transport Stream (TS). • The packets support ‘streams’ or ‘data sections’. • Streams carry higher layer packets derived from an MPEG stream. • Data sections are blocks of data carrying signaling and control data. • DVB is actually a support mechanism for MPEG. • One MPEG stream needing higher instantaneous data can ‘steal’ capacity from another with spare capacity.
DVB Packets (cont.) MPEG-2 Transport MUX Packet Randomized transport packet: Sync Bytes and randomized Data byte Reed-Solomon RS(204,188,8) Error Protected packets. Data structure after outer interleaving: Interleaving Depth I=12 Bytes
DVB Packet The DVB Transport stream consists of a series of packets 204 bytes long, 188 bytes carry information and the other 16 bytes carry an outer Reed-Solomon code. The packet is short and can survive a noisy channel subject to interference. 188 Bytes 16 Bytes Information Reed Solomon Parity block
Applied Process to Data Stream • Transport multiplex adaptation and randomization for energy dispersal; • Outer coding (i.e. Reed-solomon code); • Outer interleaving (i.e. Convolutional interleaving); • Inner coding (i.e. Punctured convolutional code); • Inner interleaving (bit-wise or symbol interleaving are block based); • Mapping and modulation; • Orthogonal frequency division multiplexing (OFDM) transmission.
Randomization /De-Randomization In order to ensure adequate binary transitions, the data of the input MPEG-2 multiplex shall be randomized in accordance with the configurations depicted in the following figure:
Randomization /De-Randomization (Cont.) • The polynomial for the Pseudo Random Binary Sequence (PRBS) generator shall be: 1 + X14 + X15
Reed‐Solomon • Reed-Solomon RS (204,188, t = 8) shortened code shall be applied to each randomized transport packet (188 byte) to generate an error protected packet. • Reed-Solomon coding shall also be applied to the packet sync byte, either non-inverted (i.e.47HEX) or inverted (i.e. B8HEX).
Reed‐Solomon (Cont.) • All of the following additions and multiplications are performed in the Galois field. • The Field Generator Polynomial is: p(x) = x8 + x4 + x3 + x2 + 1
Outer Interleaver(Cont.) • Convolutional byte-wise interleaving with depth I = 12 shall be applied to the error protected packets. This results in the interleaved data structure. • The interleaver may be composed of I = 12 branches, cyclically connected to the input byte-stream by the input switch. • Each branch j shall be a First-In, First-Out (FIFO) shift register, with depth j × M cells where M = 17 = N/I, N = 204. • The cells of the FIFO shall contain 1 byte, and the input and output switches shall be synchronized.
Inner Coding • The system shall allow for a range of punctured convolutional codes, based on a mother convolutional code of rate 1/2 with 64 states. • This will allow selection of the most appropriate level of error correction for a given service or The generator polynomials of the mother code are G1 = 171OCT for X output and G2 = 133OCT for Y output.
Inner interleaving The inner interleaving consists of bit-wise interleaving followed by symbol interleaving. Both the bit-wise interleaving and the symbol interleaving processes are block-based.
References  U. H. Reimers, "DVB-The Family of International Standards for Digital Video Broadcasting-Invited Paper," Proceedings of the IEEE, vol. 94, no. 1, pp. 173-182, Jan. 2006.  Vangelista, L. ; Benvenuto, N. ; Tomasin, S. ; Nokes, C. ; Stott, J. ; Filippi, A. ; Vlot, M. ; Mignone, V. ; Morello, A. ; , "Key technologies for next-generation terrestrial digital television standard DVB-T2," Communications Magazine, IEEE , vol. 47, no. 10, pp. 146-153, Oct. 2009.  Reljin, I.S. ; Sugaris, A.N. ;, "DVB Standard Development," in Telecommunication in Modern Satellite, Cable, and Broadcasting Services, 2009. TELSIKS '09. 9th International Conference on, Nis, 2009, pp. 263-272.  W. Fischer, Digital Video and Audio Broadcasting Technology-A Practical Engineering Guide Series: Signals and Communication Technology, 3rd ed.. Springer Heidelberg Dordrecht London New York, 2010.  Jiehan Zhou ; ZhonghongOu ; Rautiainen, M. ; Koskela, T. ; Ylianttila, M. ;, "Digital Television for Mobile Devices," Multimedia, IEEE , vol. 16, no. 1, pp. 60-71, 2009.  Nilsson, A. ; Tell, E. ; Liu, D. ; , "An 11 mm , 70 mW Fully Programmable Baseband Processor for Mobile WiMAX and DVB-T/H in 0.12 m CMOS," Solid-State Circuits, IEEE Journal of , vol. 44, no. 1, pp. 90-97, Jan. 2009.  Digital Video Broadcasting (DVB);Framing structure, channel coding and modulation for digital terrestrial television, European Broadcasting Union  DVB-T - Wikipedia, the free encyclopedia.  Digital Broadcasting: an introduction to ISDB, DVB and ATCS, Presentation slides, Lieboud Van den Broeck, 2006