Improving algorithm for blind estimation of SNR in turbo coded system

Existing algorithms for blind estimation of SNR (signal-to-noise ratio) in Turbo coded system are too complex and, in our opinion, can be improved. We propose a better algorithm that utilizes the extrinsic information of the two decoders within the Turbo code system. In the full paper, we describe our better algorithm in much detail and we give numerical results in Fig.4 and Table 2; here we just give a briefing. The proposed blind estimation algorithm can greatly decrease the complexity of the channel estimator but at the cost of some sacrifice in performance. However, as we are mostly interested in the 7-10 dB range of SNR, the sacrifice in performance is quite small. As to the error performance of our better algorithm, the estimated SNR is quite reliable as its fault probability is below 10^-3.