Iterative SNR Estimation Based on LDPC Decoding at Low SNRs
LU Jian-huaab · Communications technology · 2010
It is difficult to estimate signal-to-noise ratio(SNR) at low SNR(≤0dB).An iterative SNR estimation algorithm based on LDPC decoding is proposed.By utilizing the expectation-maximization(EM) principle and LDPC decoding,this algorithm could get rough SNR estimation.Then the difference of the code constraint feedback of the hard decision from LDPC decoding with two different SNRs is used as the errors in a decision feedback method,thus obtaining accurate SNR estimation.Simulation results indicate that this algorithm could realize accurate SNR estimation for the LDPC coded systems at the cost of fairly less computation complexity.