Research On Key Technologies In DVB-T2 And Design Of Some Modules

DVB-T2 is a new standard used for the digital terrestrial television broadcast, which is drawn up by European digital terrestrial transmission standards organization and based on the first generation terrestrial digital video broadcasting (DVB-T). The new standard provides more parameter choices than DVB-T to accommodate different channel environment, which introduces new technologies such as physical layer pipe technology (PLP), high order nodulation technology, LDPC+BCH cascade error correcting code, constellation rotation technology, MISO technology, PAPR reduction technology, multiple interleaving technologies and so on. It not only improves the network throughput rate and the system robustness, but also enlarges network coverage and reduces the cost of network building up and maintaining.This paper mainly has three parts:The introduction of constellation rotation technology can improve the system robustness in severe channels, but also improves the complexity of receiver design. This paper proposes a new simple iterative de-mapping algorithm based on hard decision, which has a lower complexity and facilitates the application in practice. Compared with the soft information iterative algorithm, the new algorithm has a little loss which is different in different channels, code rates and modulations, but no more than 1.9 dB.The P1 symbol provided in DVB-T2 can help the receiver synchronize fast. The correlation synchronization algorithm recommended in the standard has a problem of flat peak of timing measurement function. This paper analyzes the present synchronization algorithm and proposes an improved synchronization algorithm based on the P1 symbol, which solves the problem of flat peak of timing measurement function. The new algorithm improves the synchronization probability by 20% and the synchronization precision 30% at most, which precede the former algorithm at all SNRs.At the same time of researching key technologies in DVB-T2, this paper also researches the system structure of the transmitter and realizes some modules in FPGA, which includes bit interleaving module, bit mapping to constellation module, constellation rotation module, frequency interleaving module, OFDM generation module and so on.