Research Of Synchronization And Equalization Technology In DRM System

DRM(Digital Radio Mondiale) is a global unpatented digital system.It provides a digital system for the short wave,medium wave and long wave broadcasting which has a wide range cover and long distance transmission.The timbre is improved,the interference is retained,and the contents are enriched by using DRM standard on the old bandwidth.Facing with the great challenge from the TV and Internet,AM broadcasting finds its own way of developing,it also for military information to hide in the civilian broadcast transmission provides a protential means.Through research DRM stardards,the paper analyzes long wave ,medium wave,short wave band waveform design and proposes the corresponding demodulation method in the receiver.so it provides a technical basis for the military information to hide in the civilian broadcast transmission.By studying DRM systems technical standards published by the ETSI(European Telecommunication Standards Institute),understanding the DRM waveform design in the long wave,medium wave and short wave band,proposing the corresponding demodulation method in the receiver.Because synchronization and channel estimation algorithm are directly related to whether the receiver can work, they are the core of DRM reveiver, so the main subject of the paper is DRM synchronization and channel estimation algorithms. This paper analyzes the synchronization types of DRM receiver and various of synchronization error impact on the system,proposes the symbol synchronization algorithm, Integer and decimal carrier frequency offset estimation and frame synchronization algorithm for DRM system.the paper analyzes the DRM waveform characteristics ,Weighing the existing interpolation algorithms including linear Interpolation,windowed FFT Interpolation and Wiener filtering Interpolation computational complexity and effectiveness,proposes joint time-frequency domain channel estimation algotithm for DRM receiver. The simulation results show that these synchronization and channel estimation algorithms have better performance in DRM receiver.In the end,the paper simulates synchronization algorithms and channel estimation algorithms in the robust model B of DRM,the channel model is typical SW channel(channel 3).The simulation results show that when the normalized SNR is 25dB,the BER is 10 to the negative 4 power,and under the same conditions ,the DRM standard proposes that when the normalized SNR is 24.5dB,the BER is 10 to the negative 4 power.So the performance is equivalent to DRM standards,validates the effectiveness of synchronization and equalization algorithms,so these algorithms which are further optimized and improved can be used for engineering application.