THE CRITERIA OF CHOICE OF SPECTRAL-EFFICIENT SIGNALS IN WIRELESS INFORMATIONAL NETWORKS
Keywords:OFDM-signal, Fejer's theorem, Fejer's kernel, smoothing, arithmetic means summing
Wireless data transmission networks have become one of the main areas of development of the network industry due to the ease of implementation and maintenance. A certain difficulty is the objective limitation of the frequency resource. In this regard, there is a problem of ensuring the maximum available spectral efficiency of signals that carry information in exchange channels. It is shown that when decomposing an arbitrary signal into a Fourier series, signal recovery can be ensured quite successfully by applying Feuer's method of summing the average arithmetic partial sums of the series.
The problem of research of spectral efficiency with respect to smoothed OFDM-signals is considered. The functions following Fejer's method of summing of arithmetic means are used. As we know while using Fejer's theorem for summing of Fourier series the uniform monotonic convergence of partial sums of series to expanded function is guaranteed. The article shows that Fejer's method is not just useful for restoration of signals by limited number of series members, but Fejer's kernel plays the role of the tool of providing of signal spectral efficiency. Grounding on calculations we prove that due to smoothing with Fejer's kernel aid the signal form is closer to Gaussian, which is the most acceptable for optimal distribution of signal energy by time and frequency. In the future, based on the general theory of signals, in particular, uncertainty functions, it is planned to conduct separate studies and comparative analysis of signals most suitable for use in wireless networks
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