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!
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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)
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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
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6. Comparisons of DTMB & DVB-H (Cont’d)
Interleaving
Convolutional interleaving
DTMB: B=52 M=240/720
DVB-H: B=12 M=17
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7. Comparisons of DTMB & DVB-H (Cont’d)
Interleaving
Block interleaving
DVB-H in-depth interleaver (8k)
DTMB frequency interleaver (4k)
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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
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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
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10. Receiver Algorithms & Convergence Considerations
Synchronization
Correlation approach
DTMB: correlating with the known PN sequence
DVB-H: guard interval correlation (pre-FFT syn.)
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11. Receiver Algorithms & Convergence Considerations (Cont’d)
Channel estimation & equalization
DVB-H: 8k FFT
DTMB: 8k FFT (channel estimation)
3780 FFT (equalization)
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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
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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)
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14. Thank you for your attention!