Abstract: Signal to noise ratio (SNR) is required for maximum aposteriori probability(MAP) decoder of Turbo codes, otherwise there is some loss of SNR. A new algorithm of SNR estimator is proposed, which is based on the high order statistic analysis. The new algorithm is much simpler and more effective than the previous algorithms. And the new algorithm can be used for both the additive white Gaussian noise channel and the Rayleigh channel. The effectiveness of the new algorithm is verified by the computer simulations.

Key words: Turbo codes, signal to noise ratio estimation and compensation, high order statistic analysis