This paper deduces the NDA SNR estimation algorithm for QAM signals in additive Gaussian white noise channel and on the condition of the equivalent a priori probability of transition signals positioning on every constellation point by using statistics. And the detail analysis and computer simulation for 128QAM signals are done. It is proved that the whole range interested in practice can be estimated by this algorithm.
Summer T A, Wilson S G. SNR mismatch and online estimation in turbo decoding. IEEE Trans. on Communications, 1998, COM46(4): 421 - 423.[2]Ramesh A, Chockalingam A, Milstein L B. SNR estimation in generalized fading channels and its application to turbo decoding.Proc. IEEE ICC, 2001, Helsinki, Finland, 2001: 1094 - 1098.[3]Shin Dong-Joon, Sung Wonjin, Kim In-Kyung. Simple SNR estimation methods for QPSK modulated short bursts. Proc.IEEE Globalcom, 2001, San Antonio, Texas, USA, 2001: 3644-3647.[4]Jablon N K. Joint blind equalization, carrier recovery, and timing recovery for high-order QAM signal constellations[J].IEEE Trans.Signal Processing.1992, 40(6):1383-[5]John G. Proakis Digital Communication. 3rd ed., New York:McGraw-Hill, 1995:278 - 282.