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• DEVELOPMENT AND RESEARCH OF THE EQUALIZER CONFIGURATION TO INCREASE NOISE IMMUNITY IN DECAMETER RADIO LINES

  А. I. Rybakov

  212-227

  2025-10-01

  Abstract ▼

  The problem of increasing the noise immunity of decameter radio lines (DRL) in modern domestic radio communication systems, including short-wave (SW) communication, remains significant and in demand, despite the existence of numerous classical studies. The decameter radio communication systems have been chosen as the object of our analysis. Specifically, the R-016 system, which is used as a prototype, faces limitations such as its frequency range, which affects its effectiveness in conditions of variable ionospheric characteristics that negatively impact the signal level. Signal processing issues in prototypes can lead to bit errors reaching a bit error rate (BER) of 10^-3, even in the absence of significant interference. The main objective of the study is to evaluate the impact of various factors, such as changing the length of the preamble and implementing adaptive filters, on the noise immunity of systems. The analysis of the results indicates that increasing the length of the preamble improves the noise immunity of decameter radio lines. The practical significance of the results is that they can be used to improve the noise immunity of existing DFM radio communication systems that operate in variable ionospheric conditions. This paper also discusses the scientific basis for selecting an equalizer configuration for decameter radio lines to increase communication range and improve noise immunity. The developed methods provide a scientific basis for selecting effective equalizer settings, which can lead to improved communication range. To test different equalizer configurations in a Rayleigh channel, Simulink simulation is used, which confirms the correctness of the selected parameters. Experimental validation of the decameter radio line model includes the study of various preamble lengths, and the analysis of signal-to-noise ratios (SNR) at the receiver input allows for the adaptation of these parameters. Thus, the research results show that increasing the preamble length has a positive impact on the system's noise immunity. The work focuses on the modeling and operation of DFM radio lines, and the obtained results have practical significance for the active adaptation of existing radio systems in a changing ionosphere

• SEMI-MARKOV MODEL OF TELECOMMUNICATION NETWORK WITH DYNAMIC CONTROL

  D.A. Mishchenko, А.А. L’vov, А. А. Nikiforov, Alalvan Amin Raad Jihad, M.S. Svetlov

  2021-12-24

  Abstract ▼

  The paper proposes a semi-Markov model of telecommunication network. The variant of dynamic
  traffic control of queuing system as a special case of telecommunication network is considered.
  The main purpose of control is to minimize the average cost per unit of time to service the
  incoming flow of information (packets). This takes into account the different bandwidth of the
  channels, the processing speed of information in the channel and the information capacity of the
  buffers. The approach to the organization of dynamic control taking into account noise immunity
  (information reliability) and information security is discussed. The problem of dynamic control of
  a telecommunication network is considered on the example of a simple single-channel structure of
  the “point-to-point” type, which is modeled as a linear unidirectional Markov chain. The parameters
  of the service tariff, the cost of the fine for refusal of service were introduced. The analysis
  allows us to make the following remarks that the distribution of the input information flow of
  packets is Poisson, the law of distribution of the length of packets and the speed of their arrival is
  exponential, which together characterizes the Markov process. However, there are concurrent
  service delays relative to the timing of service requests, including buffer overflow delays. The proposed
  semi-Markov model of a telecommunications network can be used for more complex network
  structures. In particular, for a telecommunication network, consisting not only of one singlechannel
  information transmission system (single-channel queuing system), but representing a set
  of several systems, that is, for multichannel telecommunication networks.