Barba I. Efficiency increase of broadband subscriber access technologies through the telephone network

Purpose: efficiency increase of broadband subscriber access technologies through the telephone network using optimal systems of orthogonal harmonic signals (OHS) of a generalized class. Object: processes of signals transmission by means of the broadband subscriber access networks through the telephone network. Subject: broadband subscriber access technologies by means of the telephone network using optimal systems of orthogonal harmonic signals of a generalized class. Scientific novelty and practical significance of the obtained results: There was developed a synthesis method of OHS systems with the frequencies multiple to F0, the duration of which exceeds the interval duration of orthogonality equal to 1/F0. For the first time there were synthesized the systems of optimal OHS of a generalized class and were investigated their frequency characteristics. Methods of interference calculation have got the further development that allowed the calculation of the interference power and the transmission rate for the TS with OHS of a generalized class. There was developed a method of OHS demodulation based on the computational algorithm of the fast Fourier transformation that reduces the computational complexity of a generalized class OHS modulation ? demodulation algorithms. For the first time there were obtained mathematical models of generalized class transmission systems (TS with OHS) construction variants that allow to investigate their characteristics. For the first time there was obtained an efficiency estimation of TS with generalized class OHS, taking into account the characteristics of the transmission channel, additive noise, interferences and crosstalk. Synthesized OHS of a generalized class provide decrease of interference power caused by non-linear distortions of the transmission channel transfer functions, frequency selective fading of signals, as a result of multipath propagation, as well as increase of immunity from the pulse noises concentrated by the range. There was performed an analysis of interferences for TS with OHS of generalized class during the work through the telephone subscriber cables. The effective value of interferences in TS with the parameters of ADSL2 + for the carrier with the number 450 decreases from 4 to 8 times (12 ... 18 dB), depending on the length of the subscriber line. There were performed the calculation and analysis of achievable transmission rates in different TS with OHS. On the basis of analysis there was proved a construction optimality of TS with OHS of a generalized class according to TS-2 scheme. Under the same conditions of transmission rate growth optimal TS provides up to 5% compared with a traditional one. Valid recommendations for the design of BA on rural telephone networks can be applied on the connecting lines of the modern FOTS.