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• STUDY OF THE STABILITY OF THE MIMO-OFDM SYSTEM TO ACTIVE INTERFERENCE USING AN ADAPTIVE ALGORITHM FOR PROCESSING SPATIAL-TEMPORAL SIGNALS

  V.P. Fedosov , А. V. Tsirkulenko

  227-236

  2025-10-01

  Abstract ▼

  Modern communication systems often operate in a complex interference and signaling environment, while there are various ways to reduce the error of the restored signal. Some of the methods relate directly to mathematical processing algorithms in the receiver, however, there are other approaches based on spatial filtering of signals. In particular, in recent years, an approach based on the weighted processing of signals received from different antennas has been actively developed using the correlation matrix of the input signal, which makes it possible to use information from the antennas more efficiently by choosing an antenna with the maximum level of useful signal and lower levels of noise and interference, which is physically the formation of an equivalent radiation patterns of the receiving antenna array with a maximum on the path with the maximum level of the useful signal and minima on others. The application of this approach is of practical interest, especially in systems with active interference, for example, from electronic warfare stations, as it can improve the quality of signal recovery. Separately, it should be noted that in the case of active interference, a method based on the minimum RMS error of restoring the pilot tones should be used to select the eigenvector for weight processing (which is possible in OFDM), since if the maximum eigenvalue is selected, it is unknown whether it will be signaling or interfering if it is high. This paper presents an experimental study of an adaptive algorithm for processing spatiotemporal signals for a MIMO-OFDM communication system with different levels of active interference from an electronic warfare (EW) station. In this case, experiments are carried out both in the descending (Downlink, from the base station to the mobile) and ascending (Uplink, from the mobile station to the base station) channel using adaptation on both the BS and MS sides, and both. It is shown that the application of the algorithm can improve the quality of signal processing and reduce the bit error rate for a wide range of signal–to-noise ratios (SNR – signal-to-noise ratio), even with imperfect channel estimation (by pilot tones).

• ADAPTIVE ALGORITHM FOR PROCESSING SPATIAL-TEMPORAL SIGNALS WITH REED-SOLOMON CODING FOR A THREE-DIMENSIONAL MODEL OF A WIRELESS RADIO COMMUNICATION CHANNEL

  V.P. Fedosov , Mohammedtaqi M. Jawad Al-Musawi Wisam , S.V. Kucheryavenko

  81-90

  2025-07-24

  Abstract ▼

  Reducing the probability of errors in message transmission is important in satellite, wireless and space communication systems. Reducing the probability of bit errors in a wireless communication system is possible by using encoding of the data being sent. Using channel encoding allows detecting and correcting errors in message transmission in a noisy channel. The aim of the work is to study the effect of using Reed-Solomon codes and the algorithm of space-time signal processing in a receiver using an adaptive antenna array on increasing noise immunity in wireless radio communication systems. In the presence of complex signal propagation paths, this allows performing spatial filtering in channels with reflections. The adaptation method, considered in this paper, is based on the theory of vectors and eigenvalues of the spatial correlation matrix. For Reed-Solomon codes, the simulation results show a significant decrease in bit error rates due to the correction of transmission errors. By using adaptive algorithms for single-input multiple-output orthogonal frequency division multiplexing (SIMO-OFDM) and multiple-input multiple-output MIMO-OFDM systems together with the Reed-Solomon code for the transmitted message, the signal-to-noise ratio for a fixed bit error level was increased to 8 dB and 5 dB, respectively. The results show that the adaptive algorithm with simultaneous use of the Reed-Solomon code can increase the throughput while significantly reducing the error probability. Under conditions of multipath signal propagation, it can be argued that the use of adaptive space-time algorithms improves the noise immunity of the receiving system during signal processing.

• TRANSMITTING DATA IN 3D WIMAX CHANNEL BASED ON SISO-OFDM AND MIMO-OFDM

  V.P. Fedosov, Jaleel Sadoon Jameel, S.V. Kucheryavenko

  2021-02-13

  Abstract ▼

  This paper considers infrastructure to wireless mobile communications using Advanced-WiMAX. In this paper, the productivity performance throughput experienced the mobile users is compared in the cases of 3D SISO and 3D MIMO-channel models within a large urban cell. Re-cently, there has been substantial work and interest to expand MIMO and SISO-processing by taking into consideration in the design the elevation plane in addition to the azimuth dimension, Since the evaluation of elevation MIMO and SISO performance in 3D-channel design is needed. Bit-level simulation is performed for the channel in WiMAX operating at 2.5 GHz. The results indicate the accuracy of the 3D channel model, and the correct estimation of the 3D channel is showed. The difference in higher predicted capacity for the 3D channel model has resulted in the small-scale parameters for the SISO-case and the lower spatial correlation parameters for the MIMO-case. Different mobility speeds, the effect of the Doppler shift, several paths and the signal attenuation at a distance and with increasing frequency has been carried out in this study. Simulation runtimes are measured concerning the multi-section modulation types for both systems SISO and MIMO. Noise immunity is adversely affected by an increase in the number of spatial streams. The noise immunity is also affected by the increase in the number of antennas at the transmitters and receivers.

• ADAPTIVE ALGORITHM FOR PROCESSING SPATIAL-TEMPORAL SIGNALS FOR DATA TRANSMISSION IN 3D WIMAX CHANNEL BASED ON SIMO-OFDM PRINCIPLES

  V.P. Fedosov, Al-Musawi Wisam Mohammedtaqi M. Jawad, S.V. Kucheryavenko

  2025-01-30

  Abstract ▼

  The development of the telecommunications industry is focused on the use of wireless broadband
  communication systems that allow increasing the speed of information transfer. New technologies with
  high transmission capabilities have been developed to solve this problem. Limitation of the signal spectrum
  and signal fading in Fresnel zones due to multipath components in a wireless system deployed in
  densely built-up urban areas are significant problems in the design of wireless communication systems, as
  well as the occurrence of the Doppler effect due to the movement of the mobile station and signal attenuation
  during propagation in the channel in different frequency ranges. To increase the speed and throughput,
  it is possible to use the procedure of transmitting and receiving signals to form channels with one
  input and several outputs SIMO (Single Input Multiple Output), providing spatial filtering when choosing
  the path with the maximum signal power. The article presents the analysis and modeling of data transmission based on the SIMO system of the 3D WiMAX wireless channel. The results of comparison of signal
  processing by this method with and without the adaptive algorithm, obtained by the criterion of maximum
  signal-to-noise ratio (SNR) are presented by the dependences of the probability of occurrence of a bit
  error (BER) on the signal-to-noise ratio (SNR). As a result of modeling, it was concluded that for the same
  system, the probability of error is sensitive to a change in the modulation type, in other words, BER
  changes in accordance with a change in the type of signal modulation. It can also be concluded that SIMO
  systems are sensitive to multipath signal propagation for the same modulation type, and BER increases
  with an increase in the number of receivers since the signal-to-noise ratio SNR decreases.