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—We address the problem of frequency-selective channel estimation and symbol detection using superimposed training. The superimposed training consists of the sum of a known sequence and a data-dependent sequence that is unknown to the receiver. The data-dependent sequence cancels the effects of the unknown data on channel estimation. The performance of the(More)
— We consider the problem of estimating the parameters of a chirp signal observed in multiplicative noise, i.e., whose amplitude is randomly time-varying. Two methods for solving this problem are presented. First, an unstructured nonlinear least-squares approach (NLS) is proposed. It is shown that by minimizing the NLS criterion with respect to all samples(More)
— The problem of estimating the frequencies of harmonics in multiplicative and additive noise is addressed. The cyclic mean (CM) can be used if the multiplicative noise has nonzero mean; the cyclic variance (CV) can be used whether or not the multiplicative noise has zero mean. This paper answers the following question: Under what conditions should we use(More)
On limits of wireless communications in a fading environment when using multiple antennas, " Wirel. Pers. Layered space–time architecture for wireless communication in a fading environment when using multi-element antennas, " Bell Labs Tech. The finite-length multi-input multi-output MMSE-DFE, " IEEE Trans. turbo receiver space–time BICM over(More)
We address the problem of frequency synchronization in OFDM-based communications systems in the context of frequency-selective fading channels. Frequency offsets are estimated by inserting null sub-carriers into a single OFDM block. The paper clarifies issues related to acquisition range and identifiability of carrier frequency offset (CFO), and performance(More)
—We address the problem of carrier frequency offset (CFO) synchronization in OFDM communications systems in the context of frequency-selective fading channels. We consider the case where the transmitted symbols have constant modulus, i.e., PSK constellations. A novel blind CFO estimation algorithm is developed. The new algorithm is shown to greatly(More)
We consider the problem of estimating the frequency of a complex harmonic in the presence of additive and multiplicative noise. Two non-linear least-squares (NLLS) estimators, NLLS and NLLS , are proposed, which consist of matching the data and the squared data, respectively, with a constant amplitude harmonic. Expressions for the asymptotic covariances of(More)
The problem of channel estimation, under the data-dependent superimposed training (DDST) scheme, when no synchronisation between transmitter and receiver exists, is considered in this paper. The structure induced by the training sequence embedded in the transmitted signal is used to achieve synchronisation via projection operators, from which first, the(More)