| 1. |
- Nosikov, I A, et al.
(författare)
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Simulations of the Minimum Frequencies of Ionospheric Modes for Radio Communication Forecast
- 2021
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Ingår i: Radiophysics and Quantum Electronics. - : Springer. - 0033-8443 .- 1573-9120. ; 64:8-9, s. 605-617
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Tidskriftsartikel (refereegranskat)abstract
- We apply two promising approaches, namely, the shooting method based on global optimization and the generalized force method, to the problem of point-to-point ionospheric ray tracing where the ionospheric modes tend to the minimum frequency. In most cases, both methods are capable of finding all rays connecting the given transmitter and receiver. However, the generalized force approach is more stable in locating highly divergent high rays. Application of the methods to a long-range single-hop radio channel demonstrates their potential for expanding the simulated frequency range, refining the model ionograms in the ranges of the minimum frequency of reflection from ionospheric layers, and significantly improving the overall forecast of the lowest usable frequency. The results of numerical simulations were also compared with the experimental data. Joint application of the presented methods provides valuable means for solving applied problems of radio communication forecast.
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| 2. |
- Shapin, Alexey G., et al.
(författare)
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An Algorithm for the Exact Packet Error Probability Calculation for Viterbi Decoding
- 2018
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Ingår i: 2018 14th International Scientific Technical Conference on Actual Problems of Electronic Instrument Engineering (APEIE – 2018) – Proceedings. - : IEEE. ; , s. 282-287
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Konferensbidrag (refereegranskat)abstract
- The performance of the Viterbi decoding algorithm in a binary symmetric channel is usually estimated by a lower or an upper bounds of a bit error probability. Nowadays, there are expressions for the exact bit error probability estimation for several trivial convolutional codes. However, traffic in modern systems is packetized. Thus, packet error probability is also an important performance metric. Besides, the existed methods could not be used for the task of packet error probability estimation. Therefore this paper presents an algorithm for the calculation of the exact packet error probability for the Viterbi decoding. The algorithm is based on a recurrent search of the cases, which lead to an error free-decoding and then cumulative probabilities of these cases are calculated.
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| 3. |
- Krasheninnikov, Pavel V., et al.
(författare)
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Parameter Estimation for the Resulting Logical Channel Formed by Minimizing Channel Switching
- 2019
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Ingår i: Automation and remote control. - : Springer. - 0005-1179 .- 1608-3032. ; 80:2, s. 278-285
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Tidskriftsartikel (refereegranskat)abstract
- We propose a method for calculating the parameters of the resulting discrete channel for secondary users in cognitive radio systems formed by the algorithm for minimizing channel switchings. The availability of channel slots is defined by a simple Markov chain. We obtain mathematical expressions for determining the transition probabilities of a graph reduced to two states for any number of primary channels.
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