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Feng Yang, Jian Song, Changyong Pan, Hui Yang, Kewu Peng, Jun Wang,

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Presentation on theme: "Feng Yang, Jian Song, Changyong Pan, Hui Yang, Kewu Peng, Jun Wang,"— Presentation transcript:

1 An Initial Study on the Convergence of DVB-H and DTMB in the Physical Layer
Feng Yang, Jian Song, Changyong Pan, Hui Yang, Kewu Peng, Jun Wang, Zhixing Yang Dept. EE Tsinghua University This work is partly supported by EU funded MING-T project.

2 Brief Introduction of MING-T
MING-T = Multistandard Integrated Network convergence for Global Mobile and Broadcast Technologies Main Objectives of the Project Incorporate both DVB-H and DTMB into the multi- standard framework. ... from project management handbook Convergence of DVB-H and DTMB ChinaCom2007 ShangHai

3 Brief Introduction of MING-T (Cont’d)
Prototype using two demodulators However, single chip is more attractive! ChinaCom2007 ShangHai

4 Comparisons of DTMB & DVB-H
Randomization Similarities The same PRBS, the same initial state Differences Sync byte: DVB (untouched) DTMB (Randomized) Reset: DVB (every 8 TS) DTMB (every signal frame) ChinaCom2007 ShangHai

5 Comparisons of DTMB & DVB-H (Cont’d)
Forward Error Correcting (FEC) coding DVB-H : RS + Convolutional code RS(204,188) derived from RS(255,239) Convolutional codes : 1/2, 2/3, 3/4, 5/6, 7/8 DTMB : BCH + LDPC BCH(762,752) derived from BCH(1023,1013) LDPC with 3 code rates as the inner code ChinaCom2007 ShangHai

6 Comparisons of DTMB & DVB-H (Cont’d)
Interleaving Convolutional interleaving DTMB: B=52 M=240/720 DVB-H: B=12 M=17 ChinaCom2007 ShangHai

7 Comparisons of DTMB & DVB-H (Cont’d)
Interleaving Block interleaving DVB-H in-depth interleaver (8k) DTMB frequency interleaver (4k) ChinaCom2007 ShangHai

8 Comparisons of DTMB & DVB-H (Cont’d)
Frame Structure C-OFDM : Process in Frequency domain Parameter refresh : 1ms; Signal lock : 100ms TDS-OFDM : Process in Time/Frequency domain Channel estimation : 0.56 ms; Signal lock : 5ms Copy CP Data+Pilot OFDM Symbol C-OFDM PN Data Signal Frame 500μs TDS-OFDM ChinaCom2007 ShangHai

9 Comparisons of DTMB & DVB-H (Cont’d)
Summary TDS-OFDM vs C-OFDM, Using PN brings Higher spectrum efficiency Faster channel synchronization BCH+LDPC vs RS+Convolutional code for better coding gain, therefore, lower Eb/N0 required for the same BER Larger coverage Better availability Long time-domain interleaver Better immunization to impulsive noise ChinaCom2007 ShangHai

10 Receiver Algorithms & Convergence Considerations
Synchronization Correlation approach DTMB: correlating with the known PN sequence DVB-H: guard interval correlation (pre-FFT syn.) ChinaCom2007 ShangHai

11 Receiver Algorithms & Convergence Considerations (Cont’d)
Channel estimation & equalization DVB-H: 8k FFT DTMB: 8k FFT (channel estimation) 3780 FFT (equalization) ChinaCom2007 ShangHai

12 Receiver Algorithms & Convergence Considerations (Cont’d)
De-interleaving Convolutional de-interleaver DTMB: B=52, M=720 DVB-H: B=12, M=17 Block de-interleaver DVB-H: 8K DTMB: 4K ChinaCom2007 ShangHai

13 Receiver Algorithms & Convergence Considerations (Cont’d)
FEC decoder DVB-H Convolutional code: Viterbi Algorithm (VA) RS code: syndrome computation, key-equation solver, Chien search and error evaluator DTMB (LDPC) Hard-decision : Bit-Flipping (BF) Soft-decision : Sum-Product Algorithm (SPA) ChinaCom2007 ShangHai

14 Thank you for your attention!

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