Research On Synchronization Algorithms In DVB-T2 System

The European Telecommunications Standards Institute(ETSI) issued DVB-T which is the first terrestrial broadcasting standard using OFDM technology in 1997. To improve the efficiency of spectrum using, then ETSI organization issued the second generation standard DVB-T2. It has a new frame structure compared with DVB-T. In particular, the system has the capacity to achieve synchronization fastly and against a large carrier frequency offset by the introduction of the P1 symbol. Because the traditional OFDM synchronization algorithm doesn’t apply to P1 symbol, therefore some specific algorithms are needed for the P1 symbol’s structural features.The study is unfolded around the system synchronization on the basis of DVB-T2 frame structure characteristics and analyzing the system’s synchronization requirements. The main tasks include the following:1. First of all, introduce DVB-T2 physical layer module, system frame structure, synchronization resources. Then analyze the impact of the synchronization error in the DVB-T2 system. The study of synchronization algorithms in DVB-T2 is necessary. The synchronization requirements of the system are described at last.2. The synchronization algorithms of DVB-T2 system based on P1 symbol are researched. Based on the analysis of P1 symbol’s structural characteristics, subcarrier distribution and data generation process, the detection, timing synchronization, frequency synchronization and decoding algorithms are studied. The detection and coarse timing synchronization and fractional CFO estimation algorithms are studied in the pre-FFT stage, and coarse timing synchronization performance can’t meet the requirements of decoding. The integer CFO and fine timing synchronization algorithms are studied in the post-FFT stage. The integer CFO algorithm can estimate accuracyly and widely. Fine timing synchronization will significantly enhance the accurately of the timing and is ready for decoding. P1 is decoded after completion of the synchronization. Its performance and the performance with ideal synchronization are almost the same.3. The frequency synchronization algorithms based on the pilot sequence of DVB-T2 are studied. Because SFO can’t be estimated in P1 symbol, the SFO estimation algorithms based on the continuous pilot are studied. When the local oscillator frequency of the transmitter and the receiver don’t match, then the frequency offset is generated. The system will not tolerate the deviation as the time. It is necessary to track the frequency offset. The frequency offset tracking algorithms are studied based on the phase increment of the continuous pilot in OFDM symbols. The tracking of CFO and SFO can work very well even in very low SNR, and stability estimation bias is in the system range.4. A variety of synchronization algorithms in DVB-T2 system are simulated and studied deeply. Simulation results show that the designed synchronization scheme meet the synchronization requirements of demodulation and decoding in DVB-T2 system.