Research On Key Technology Of DVB-T2 Receiver

The Second Generation Digital Video Broadcasting-Terrestrial(DVB-T2)promulgated in Europe is the most widely used digital terrestrial television standard at present.It adopts the latest modulation and coding technology,cites a new frame structure,and has a higher data transmission rate and spectrum utilization than DVB-T,whose stability and flexibility have also been significantly improved.However,while its performance is improved,the complexity of the receiver implementation is also increased,and the performance of the receiver in a low signal-to-noise environment is more demanding.At present,the domestic DVB-T2 chip still has a significant gap with other developed countries,so the research on the key technology of the DVB-T2 system receiver is of great significance.To improve the performance of the DVB-T2 system in a low signal-to-noise environment,synchronization is the first key task to be solved.This paper first studies the dual correlation detection algorithm based on P1 symbols proposed in the standard and two improved algorithms.An improved algorithm based on P1 symbols was proposed for the problems such as the peak of correlation peak is not sharp enough,the sub-peak is obvious,and the performance is poor in a low signal-to-noise environment.The algorithm first uses the conjugate symmetry of the P1 symbol itself and the dual correlation characteristics between its main part and the two frequency-shifted copies to design a measurement function,and then according to the influence of the sub-peak value,the two branches are respectively extracted with parity to reduce the output peak value of the small irrelevant part.The simulation results show that the proposed algorithm has sharper peaks similar to pulses and significantly reduces the impact of sub-peaks,which also improves the performance of timing synchronization,especially in a low signal-to-noise environment,accurate timing can be achieved at-9d B.Channel estimation technology is another key technology of the receiver,and its estimation accuracy directly affects the performance of the entire receiver.In this paper,the existing channel estimation algorithm has been studied in depth,and the simulation results of its estimation performance under multipath channel are obtained.Under the premise of taking into account the complexity and performance,an estimation scheme combining least squares(LS)and time-frequency bilinear interpolation was proposed;then,aiming at the distribution characteristics of the cyclic shifts of the discrete pilots in the system,an edge compensation scheme based on P2 symbols is proposed,which is based on the dense distribution of P2 pilots and its distribution relationship with the scattered pilots,and uses P2 pilots to compensate for the subcarrier estimation where the pilot does not arrive in the previous data symbol.The simulation results show that the proposed compensation scheme has a certain performance improvement under the same channel environment.