This article presents an iterative minimum mean square error- (MMSE-) based method for the joint estimation of\r\nsignal-to-noise ratio (SNR) and frequency-selective channel in an orthogonal frequency division multiplexing (OFDM)\r\ncontext. We estimate the SNR thanks to the MMSE criterion and the channel frequency response by means of the\r\nlinear MMSE (LMMSE). As each estimation requires the other one to be performed, the proposed algorithm is iterative.\r\nIn this article, a realistic case is considered; i.e., the channel covariance matrix used in LMMSE is supposed to be totally\r\nunknown at the receiver and must be estimated. We will theoretically prove that the algorithm converges for a\r\nrelevantly chosen initialization value. Furthermore simulations show that the algorithm quickly converges to a solution\r\nthat is close to the one in which the covariance matrix is perfectly known. Compared to existing SNR estimation\r\nmethods, the algorithmimproves the trade-off between the number of required pilots and the SNR estimation quality.
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