Signal-Code Structures for Information Transmission with Minimal Adjacent Channel Interference
The paper considers the mathematical foundations for the formation of an optimal complex orthogonal basis for a finite set of frequency ranges and methods for encoding and decoding a signal-code structure. The number of excluded frequency ranges can be unlimited and of various widths. The number of orthogonal vectors used is determined by the total width of the used channel. The results of comparative computational experiments on estimating the fraction of out-of-band radiation for different transmission frequency intervals are presented. The calculation results show the superiority of the complex orthogonal subband basis over orthogonal frequency multiplexing in the fraction of out-of-band energy leakage, while using eigenvectors with the maximum eigenvalue. The scalar product of eigenvectors shows the minimum level of mutual influence. Then there is the possibility of encoding and decoding signal-code structures with a high level of resistance to the effects of fluctuation noise during transmission.