An efficient SNR estimate scheme for a turbo decoder over quasi-static channels

The performance of the Log-MAP turbo decoders relies heavily on the accurate knowledge of the channel signal-to-noise ratio (SNR) characteristics. Several SNR estimate schemes that are based on the second-order statistics of the received vectors were accordingly proposed in literatures. In this paper, we present an alternative SNR estimate scheme that requires only the first-order statistics and hence is much less complex and more efficient. Theoretical analysis on the estimate accuracy based on the Independent Gaussian Assumption is also provided, and is subsequently examined by simulations. Our results indicate that the proposed efficient channel SNR estimate can yield a comparable system performance with much less computational effort than the existing channel SNR estimate schemes.