Increasing the data transfer rate is an urgent task in cellular, high-frequency (HF) and special communication systems. The most common way to increase the data rate is to expand the bandwidth of the transmitted signal, which is often achieved through the use of multitone systems. One such system is the filter bank multicarrier (FBMC). In addition, speed improvements are achieved using multi-input–multi-output (MIMO) systems. In this study, we developed an algorithm for equalizing FBMC signals with offset-QAM modulation (OQAM) with self-interference compensation due to its correlation properties in a MIMO channel with memory. An analytical derivation of the proposed algorithm and an analysis of the computational complexity are given. According to the results of simulation modeling and a comparative analysis of performance in terms of the bit error rate and error vector magnitude with solutions with similar computational complexity, a similar level of performance was shown compared to a more complex parallel multistage algorithm, and a better performance was demonstrated compared to a one-tap algorithm.

In this article, an algorithm for joint estimation of communication channel gains and signal distortions in a direct conversion receiver is proposed. The received signal model uses approximations with a small number of parameters to reduce the computational complexity of the resulting algorithm. The estimation algorithm is obtained under the assumption of a priori uncertainty about the characteristics of the communication channel and noise distribution using the linear least squares method. Estimation is performed first by the test sequence, then by the information symbols obtained after detection. In addition, an analysis of the noise immunity of quadrature amplitude modulation (QAM) signal reception is carried out using different approximating structures in the estimation algorithm for systems with a single transmitting and receiving antenna (SISO) and for systems with multiple transmitting and receiving antennas (MIMO). Furthermore, this article examines the influence of the duration of the test signal, the number of sessions of its transmission, and the channel extrapolation interval on the quality of signal reception.

The article presents the methods and algorithms for compensating for the dispersion distortion of the wideband signals of the decameter radio communication lines. Methods for estimating the slope of the dispersion characteristic, namely, the maximum likelihood estimation method (MLE), the evaluation by dividing the signal into subbands are considered. Methods and algorithms for compensation of dispersion distortion of wideband signals are proposed. The first method: compensation during the detection of a signal by a matched filter. The second method: compensation using digital filter banks. The third method: signal processing by the tracking compensator. The results of field experiments to compensate for dispersion distortion in a wideband signal on a single-track track with a length of about 2900 km are presented.

The article proposes a device for compensation of dispersion distortions, based on the modification of the classic M-channel system of digital banks of analysis and synthesis with an ideal recovery. The modification consists in adding additional compensatory delays and phase shifts in the synthesis channels, determined by the calculation method, depending on the slope of the frequency dispersion of the ionospheric channel.

The article proposes a computationally effective scheme of the dispersion distortions compensation device, based on the modification of the classical 2M-channel digital filter banks. The modification consists in adding additional compensation delays, phase shifts and interpolation filters in the synthesis channels, determined by the calculation method, depending on the frequency dispersion slope of the ionospheric channel. Reduction of the number of arithmetic operations of is achieved by applying a polyphase structure of synthesis and analysis filters and applying the fast Fourier transform. Interpolator filters are needed to solve the problem of compensating for group delays in subchannels equal to the fractional values of the sampling intervals.

The article proposes a computationally effective scheme of the dispersion distortions compensation device, based on a filter bank using the Farrow filter. The possibility of constructing a tracking compensator for dispersion distortions of broadband signals when transmitting them through the ionospheric channel is considered. The tracking compensator allows the estimation of dispersion distortions and their compensation. The results of simulation of the proposed algorithms are presented: the obtained estimate and the true value of the frequency dispersion parameters.