Adaptive Equalizer Design In Single Carrier System

The single carrier time-domain equalization is one key technology to overcome multipath interference in digital television transmission receivers. Based on the frame format features of digital terrestrial multimedia broadcasting and cable digital television and the basic characteristics of the corresponding transmission channel, an adaptive equalization algorithm with high reliability and low complexity is investigated in this paper.Combined with the channel prediction algorithm based on PN training sequence, an initializing formula on forward taps is derived in this paper. A tap-initialized algorithm suitable for practical transimission system is proposed. In addition, a sparse tap algorithm is studied to improve the system's precision and convergence speed efficiently with low complexity. Considering the systems without auxiliary training sequence, such as the open cable digital television standard, the algorithm of recognizing the modulation mode of the system is proposed to reduce the difficulty of the equalizer decision. Besides, a multi-module algorithm is introduced combined with carrier recovery and equalization technologies to conquer the residual carrier phase offset. Meanwhile, the soft decision directed and variable step adjustment methods are exploited to decrease the error propagation. Finally, a complete implementation scheme for equalization combining the TCM decoding is designed in this paper. Simulation experiments on the equalizer performance are given using Matlab and C programming languages and the results show that the proposed equalizer algorithm has better performance in frequency selective fading channels than traditional algorithms.