1,721,038 research outputs found
Support vector machines for signal processing
No full textThe chapter deals with the use of the support vector machine (SVM) algorithm as a possible design method in the signal processing applications. It critically discusses the main difficulties related with its application to such a general set of problems. Moreover, the problem of digital channel equalization is also discussed in details since it is an important example of the use of the SVM algorithm in the signal processing. In the classical problem of learning a function belonging to a certain class of parametric functions (which linearly depend on their parameters), the adoption of the cost function used in the classical SVM method for classification is suggested. Since the adoption of such a cost function (almost peculiar to the basic SVM kernel-based method) is one of the most important achievements of the learning theory, this extension allows one to define new variants of the classical (batch and iterative) minimum-mean square error (MMSE) procedure. Such variants, which are more suited to the classification problem, are determined by solving a strictly convex optimization problem (not sensitive, therefore, to the presence of local minima). Improvements in terms of the achieved probability of error with respect to the classical MMSE equalization methods are obtained. The use of such a procedure together with a method for subset selection provides an important alternative to the classical SVM algorithm
Identification of polyperiodic Volterra systems by means of input-output noisy measurements
No full textA new method for blind synchronization for OFDM/OQAM systems
No full textThe paper deals with the problem of blind synchronization for OFDM/OQAM systems. Specifically, by exploiting the approximate conjugate-symmetry property of the beginning of a burst of OFDM/OQAM symbols, due to the presence of the time offset, a new procedure for timing and CFO synchronization is proposed. The performance of the proposed estimators is analyzed by computer simulations; the results show that the proposed methods may provide acceptable performance for reasonable values of the signal-to-noise ratio
Data-aided synchronization for OFDM/OQAM systems
No full textThe paper deals with the problem of preamble-based synchronization for OFDM/OQAM systems. Specifically, by exploiting the conjugate symmetry property of a recently proposed preamble structure, a simple and robust procedure for timing and CFO synchronization is proposed. The root mean square error of the proposed estimators and the overall performance of an OFDM/OQAM system exploiting them are evaluated via computer simulations
On the Uplink Spectral Efficiency of the FBMC-OQAM Transceiver
No full textThe analysis of the spectral efficiency that can be achieved by using the FBMC-OQAM transceiver in the uplink of the modern wireless networks is carried out. Such efficiency is studied in a scenario where the limitations are introduced by interferences due to the multiple access scenario, rather than by the presence of hostile wireless channels. The analysis shows that the FBMC-OQAM transceiver is able to achieve significant values of spectral efficiency also in the most difficult conditions, i.e., when the subcarriers blocks to be shared according to a time multiplexing approach are much small
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