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Digital Video Broadcasting Final Custom Implementation DSP Course Alireza Mazraee Farahani Spring 2010 1 Class presentation for the course: “Custom Implementation.

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Presentation on theme: "Digital Video Broadcasting Final Custom Implementation DSP Course Alireza Mazraee Farahani Spring 2010 1 Class presentation for the course: “Custom Implementation."— Presentation transcript:

1 Digital Video Broadcasting Final Custom Implementation DSP Course Alireza Mazraee Farahani Spring 2010 1 Class presentation for the course: “Custom Implementation of DSP Systems” All the materials are copy rights of their respective authors as listed in references.

2 DVB Overview  DVB Project is an industry-led consortium of over 300 companies  The DVB Project was launched on 10 th 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 2

3 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. 3

4 Digital TV Standards Adoption Map. 4

5 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 5

6 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 Bytes16 Bytes Information Reed Solomon Parity block 6

7 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. 7

8 DVB Functional Block Diagram [7] 8

9 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[7]: 9

10 Randomization /De-Randomization (Cont.) The polynomial for the Pseudo Random Binary Sequence (PRBS) generator shall be: 1 + X 14 + X 15 10

11 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). 11

12 Reed ‐ Solomon (Cont.) All of the following additions and multiplications are performed in the Galois field. The Field Generator Polynomial is: p(x) = x 8 + x 4 + x 3 + x 2 + 1 12

13 Reed ‐ Solomon (Cont.) [7] 13

14 Outer Interleaver [7] 14

15 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. 15

16 Outer Deinterleaver 16

17 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. 17

18 Inner Coding(Cont.) 18

19 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. 19

20 Viterbi Decoder 20

21 Viterbi Decoder(Cont.) 21

22 References [1] 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. [2] 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. [3] 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. [4] 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. [5] Jiehan Zhou ; Zhonghong Ou ; Rautiainen, M. ; Koskela, T. ; Ylianttila, M. ;, "Digital Television for Mobile Devices," Multimedia, IEEE, vol. 16, no. 1, pp. 60-71, 2009. [6] 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. [7] Digital Video Broadcasting (DVB);Framing structure, channel coding and modulation for digital terrestrial television, European Broadcasting Union [8] DVB-T - Wikipedia, the free encyclopedia. [9] Digital Broadcasting: an introduction to ISDB, DVB and ATCS, Presentation slides, Lieboud Van den Broeck, 2006 22

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