Abstract:

Three priori information aided SNR estimation algorithm is proposed based on maximum likelihood sequential criterion. Compared with the existing harddecision aided SNR estimation algorithm, the proposed algorithm decreases estimation error in low SNR state. The performance of the algorithm in the beginning of iteration and in the next iterations in turbo equalizer is analyzed. According to different number of iteration, switching one algorithm to another can raise the estimation precision, and lower complexity. The new algorithms only use small number of data symbols, they can also handle a large range of SNR.

Key words: SNR estimation, priori information, harddecision aided, softdecision aided, priori probability aided