Lui Sakai

Parity and column twist bit interleaver for DVB-T2 LDPC codes

We introduce a parity and column twist bit interleaver which improves performance of DVB-T2 LDPC codes in channels with erasure. The key idea is avoiding multiple bits on constellation symbols which are connected to the same check node, in order to minimize damage by an erased symbol. By simulation we observed significant performance improvement in faded erasure channels, and the higher erasure probability, the more gain we observed.

Terrestrial broadcast system using preamble and frequency division multiplexing

Broadcast systems based on FDM (Frequency Division Multiplex) have the advantage of near continuous demodulation of the broadcast signal, allowing accurate and continuous tracking of channel conditions which is particularly useful for mobile reception. This has been employed in the ISDB-T standard used in Japan, Brazil and other countries. However, as designed in ISDB-T the broadcast signal lacks the ability to send system parameters such as FFT size, GI size and so on before the receiver begins demodulation. The receiver must blindly estimate such system parameters before it can read the other detailed parameter information using the TMCC pilot carriers. This takes time, usually one frame or longer. This paper proposes a next generation FDM system which enables the original advantages of FDM to be retained, while allowing additional advantages by employing an additional small signal (Preamble 1) which imparts essential information such as FFT size, GI size and pilot pattern to the receiver to enable immediate demodulation of the broadcast signal based on known parameters rather than blind estimation. Following demodulation of the first preamble, demodulation of the second preamble (Preamble 2) allows immediate knowledge of the all subsequent parameters contributing to faster demodulation of the overall signal.