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“Digital
Signal Processing” No. 2-2023 |
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The influence of the spatial structure on the capacity of wireless MIMO systems in the presence of interference
Yu.N. Parshin, e-mail: parshin.y.n@rsreu.ru
V.N.T Nguyen , e-mail: thuan.nvn88@gmail.com
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: MIMO system, channel capacity, spatial structure, interference.
Abstract
The article deals with channel capacity of MIMO system. It's known that MIMO systems allow to increase efficiency of data transmission, increasing capacity of the communication channel and reducing the number of errors when receiving data. The paper analyzes the capacity of MIMO telecommunication system depending on the spatial structure of antennas in the presence of interference.
The effectiveness of spatial processing largely depends on the spatial structure of the antenna system - the number of antennas, their location in space. Optimization of the spatial structure makes it possible to increase the efficiency of radio systems operating under conditions of spatially correlated interference. The spatial structure determines the spatial correlation matrix of interference, the correlation properties of the channel coefficients of MIMO radio systems, as well as the matrix of mutual impedances of the receiving and transmitting antenna systems. The spatial structure affects a whole range of characteristics of the MIMO radio system, which is especially noticeable when the size of the antenna system is reduced.
The dependence of capacity on the number and location of antennas in the transmitting and receiving antenna systems in the presence of interference are investigated. The capacity of the MIMO communication system is calculated when transmitting uncorrelated messages, the action of spatially uncorrelated interference, noise and the channel matrix. To construct a channel matrix using the angular spectrum and spatial structure of the antenna system in the antennas of the receiving or transmitting antenna systems. The article mentions the mutual influence of signal and interference in the antenna system using a matrix transmission coefficient, which is calculated by the matrix of mutual antenna impedances, the diagonal matrix of the load impedances of the receiving path. The article uses a linear filter to convert correlated interference into uncorrelated interference.
The capacity of the system increases with an increase in the number of transmitting and receiving antennas, especially when the numbers of transmitting and receiving antennas are the same. Under the action of spatially correlated interference, the capacity decreases several times with a given number of transmitting and receiving antennas. Interference compensation depends on the number of receiving antennas. The capacity also depends on the distance between the antenna elements. With a sufficient value of the distance between the elements (greater than or equal to half the wavelength), it is possible to achieve the maximum value of the capacity and the interference compensation coefficient.
The simulation results allow us to justify the choice of the number of antennas to obtain a given capacity in wireless MIMO systems.
References
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4. Volker Kuhn. Wireless communications over MIMO channels: Applications to CDMA and multiple antenna systems. John Wiley & Sons, 2006.
5. Grachev M.V., Parshin Yu.N. Analysis of the bandwidth of the MIMO communication system taking into account the mutual influence of the channels of the receiving tract. Radar, navigation, communications: Proceedings of the XXV International Scientific and Technical Conference (April 16-18, 2019). In 6 volumes. Voronezh State University; JSC Concern Constellation. Voronezh: Publishing House VSU, 2019. Vol. 5. pp. 242-248.
6. Parshin Yu.N., Ksenzov A.V. The influence of spatial correlation on the efficiency of optimizing the spatial structure of a multi-antenna system with a spaced reception. Bulletin of the Ryazan State Radio Engineering Academy. Ryazan: RGRTU, issue 19, 2006. pp. 54-62
7. Parshin Yu.N., Gusev S.I. Determination of the optimal spatial structure of the signal processing system by the criterion of maximum likelihood. Bulletin of the Ryazan State Radio Engineering Academy. Vol.2. Ryazan: RGRTA, 1997.pp.5-11.
8. Kolupaeva A.S., Parshin Yu.N. The bandwidth of the MIMO system in the presence of spatially correlated interference. Radar, navigation, communication: Proceedings of the XXVI International Scientific and Technical Conference. Voronezh: VSU Publishing House, 2020, Vol. 5. pp. 156-161.
9. Sosulin Yu.G., Kostrov V.V., Parshin Yu.N. Evaluation and correlation signal processing and interference compensation. M.: Radio Engineering, 2014. 632 p.
10. Parshin Yu.N., Grachev M.V. Multi-stage reconfigurable signal processing in a spatially distributed radio system. Bulletin of the Ryazan State Radio Engineering University Ryazan: RGRTU, 2019, No. 67 p. 3-10.
11. Parshin Yu.N., Gusev S.I. The influence of the signal-interference situation on the optimal spatial structure of the antenna system. Bulletin of the Ryazan State Radio Engineering Academy. Vol.4. Ryazan: RGRTA, 1998. pp. 117-120.
12. Sazonov D. M. Antennas and microwave devices: Textbook for radio engineering specialties of universities. M.: Higher School, 1988. 432 p.
13. Parshin Yu.N. Space time signal processing and interference compensation. M.: COURSE, 2021. 200 p.
Time-Frequency Signal Processing in the Doppler Radio
V. K. Klochko, e-mail: klochkovk@mail.ru
B. H. Vu, e-mail: ronando2441996@gmail.com
Ryazan State Radio Engineering University, Russia, Ryazan
Keywords: radio signal processing, Doppler receivers, time-frequency analysis, signal detection, parameter estimates, mathematical modeling.
Abstract
Many works are devoted to solving the problem of over-resolution of sources, which can be divided into the following three groups: works based on mathematical methods of extracting information about sources due to correlation processing or decomposition of signals according to a certain basis; works based on the positioning of several mutually oriented and synchronized receiving stations; works based on joint time-frequency signal processing. This work adheres to the third direction. Taking into account the known limitations of the methods of time-frequency analysis in solving the problem of superresolution – a priori a given number of sources and a large amount of calculations, in this paper we propose author solutions free from these limitations. The problem of distinguishing signals from several mobile sources in a multichannel Doppler radio receiver is solved. Based on the received signals, a decision is made on the availability of sources, their number and spatial coordinates are estimated. The aim of the work is to supersolve moving sources of reflection of radio signals that are not distinguishable by Doppler frequency, and to determine their spatial coordinates. It is proposed to increase the Doppler frequency resolution due to joint signal processing in the time and frequency domains. In the time domain, the time points of arrival of signals from sources are detected and their number is set at each time interval. In the frequency domain for each time interval, frequencies are detected at which the sources are distinguishable and not distinguishable. Estimates of coordinates of distinguishable sources, as well as those not distinguishable in the presence of two sources, are determined. The advantage of time-frequency signal processing is shown.
References
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3. Klochko V.K., Kuznetsov V.P., Levitin A.V. and others. Algorithms for determining the coordinates of moving targets based on multichannel Doppler radar // Bulletin of the Ryazan State Radio Engineering University. 2015. No. 53. pp. 3-10. (in Russian)
4. Marpl.-ml. S.L. Digital spectral analysis and its applications: trans. from English M.: Mir, 1990. 584 p. (in Russian)
5. Methods and algorithms of digital spectral analysis of signals: textbook / V. I. Koshelev. — M.: COURSE, 2021. — 144 p. (in Russian)
6. Klochko V. K. An algebraic approach to the direction finding of objects in a multi-position system of receivers // Digital signal processing. 2022. ¹ 1. Pp. 28 - 33. (in Russian)
7. Klochko V. K., Wu Ba Hung. Algorithms for increasing the resolution of the additional frequency in the system of radio receivers // Radio engineering and telecommunications systems. 2022. No. 47. pp. 31 – 42. (in Russian)
8. Klochko V. K., Wu Ba Hung. Detection of mobile sources by a system of radio receivers // Digital signal processing. 2022. ¹ 4. Pp. 50 - 55. (in Russian)
9. F. Hlawatsch, G. Matz, H. Kirchauer, and W. Kozek , Time-frequency formulation, design, and implementation of time-varying optimal filters for signal estimation, IEEE Trans. Signal Proc-ess., 48, 1417-1432, May 2000.
10. K. Ghartey , A. Papandreou-Suppappola, and D. Cochran, On the Use of Matching Pursuit Time-Frequency Techniques for Multiple-Channel Detection, in Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing, 5, 3201-3204, May 2001.
11. Papandreou-Suppappola, Antonia, Applications in time-frequency signal processing (Elec-trical engineering and applied signal processing series), New York, 2002, 397 p.
12. Klochko V. K., Kuznetsov V. P., Wu Ba Hung. Estimation of parameters of radio signals from mobile low-altitude objects // Bulletin of the Ryazan State Radio Engineering University. 2022. No. 80. pp. 12-23. (in Russian)
13. Mathematical methods of space-time signal processing in radio and optoelectronic systems: monograph / V. K. Klochko. Ryazan: IP Konyakhin A.V. (Book Jet), 2020. 164 p.
14. Models of uncertainty in theory and applications: studies. manual / V. K. Klochko. M.: COURSE. 2022. 204 p. (in Russian)
15. Kuznetsov V. P., Churakov E. P. Kalman filter system for estimating the parameters of the reflected signal // Bulletin of the Ryazan State Radio Engineering University. 2015. No. 1 (Issue 51). pp. 9-14. (in Russian)
Synthesis and analysis of detector-meters Doppler signals
D.I.Popov, e-mail: adop@mail.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: detection-estimation algorithms, analysis, equidistant and non-equidistant signals, likelihood ratio, synthesis, block diagrams, phase.
Abstract
Algorithms of joint detection-estimation of equidistant and non-equidistant bundles (sequences) of coherent signals are considered. A statistical description of an equidistant bundle of signals is given, on the basis of which, by calculating the likelihood ratio and then averaging it, an invariant to the Doppler phase detection algorithm is synthesized.
An algorithm for estimating the Doppler phase is synthesized by the method of maximum law-similarity. A block diagram implementing synthesized algorithms is given. To expand the range of one-digit estimation of the Doppler frequency (phase) while maintaining an unambiguous estimation of the delay time (range), it is proposed to use a non-equidistant sequence of pulses – in the simplest case with alternating periods of intrusion.
The corresponding detection algorithm has been synthesized, on the basis of which a modified algorithm has been obtained. By solving a system of truthfulness equations with respect to Doppler phase shifts in alternating repetition periods, an algorithm for estimating the difference Doppler phase and an algorithm for unambiguous estimation of the radial velocity of the target are obtained. The block diagrams of detectors-meters of non-equidistant signals based on the algorithms of synthesized and modified detectors and algorithms for unambiguous measurement of the Doppler phase and radial velocity are presented.
The analysis of the detector-meters showed that the use of the modified detection algorithm compared with the use of the synthesized algorithm provides significant gains in the value of the threshold signal-to-noise ratio and leads to losses in the accuracy of the Doppler phase measurement.
References
1. Skolnik M.I. Introduction to Radar System, 3rd ed., New York: McGraw-Hill, 2001. – 862 p.
2. Richards M.A., Scheer J.A., Holm W.A. (Eds.). Principles of Modern Radar: Basic Principles. New York: SciTech Publishing, IET, Edison. 2010. – 924 p.
3. Melvin W. L., Scheer J.A. (Eds.). Principles of Modern Radar: Advanced Techniques. New York: SciTech Publishing, IET, Edison, 2013. – 846 p.
4. Radar Handbook / Ed. by M.I. Skolnik. 3rd ed. McGraw–Hill, 2008. 1352 p.
5. Popov D.I. Adaptacija nerekursivnyh rezhektornyh fil'trov // Izvestija vuzov. Ra-diojelektronika. 2009. vol. 52. no. 4. P. 46-55. (in Russian).
6. Popov D.I. Autocompensation of the Doppler phase of clutter // Cifrovaja obrabotka signalov. 2009. no 2. pp. 30–33. (in Russian).
7. Popov D.I. Avtokompensacija doplerovskoj fazy mnogochastotnyh passivnyh pomeh // Vestnik Rjazanskogo gosudarstvennogo radiotehnicheskogo universiteta. 2018. no. 65. pp. 32–37.
8. Popov D.I. Adaptive suppression of clutter // Cifrovaja obrabotka signalov. 2014. no. 4. pp. 32-37. (in Russian).
9. Popov D.I. Adaptivnije regektornjie filtrij kaskadnogo tipa // Cifrovaya obrabotka signalov. 2016. no. 2. pp. 53-56. (in Russian).
10. Popov D.I. Adaptive notch filter with real weights // Cifrovaya obrabotka signalov. 2017. no. 1. pp. 22-26. (in Russian).
11. Popov D.I. Optimizacja nerekursivnjih regektornjie filtrov s chastichnoj adaptaciej // Cifrovaya obrabotka signalov. 2018. no. 1. pp. 28-32. (in Russian).
12. Popov D.I. Optimizacija rezhektornyh fil'trov po verojatnostnomu kriteriju // Cifrovaja obrabotka signalov. 2021. no. 1. P. 55-58. (in Russian).
13. Kuz'min S.Z. Cifrovaja radiolokacija. Vvedenie v teoriju (Digital radar. Introduction to Theory). Kiev: KViC, 2000. 428 p. (in Russian).
14. Cifrovaja obrabotka signalov v mnogofunkcional'nyh radiolokatorah. Metody. Algoritmy. Apparatura: monografija (Digital signal processing in multifunctional radars. Methods. Algorithms. Equipment: monograph) / pod red. G.V. Zajceva. M.: Radiotehnika, 2015. 376 p. (in Russian).
15. Klochko V.K., Kuznecov V.P., Levitin A.V. i dr. Algoritmy opredelenija koordi-nat dvizhushhihsja celej na baze mnogokanal'noj doplerovskoj RLS // Vestnik Rjazanskogo gosudarstvennogo radiotehnicheskogo universiteta. 2015. no. 53. pp. 3-10. (in Russian).
16. Klochko V.K., Kuznecov V.P., Vu Ba Hung. Ocenivanie parametrov radiosignalov ot podvizhnyh malovysotnyh ob#ektov // Vestnik Rjazanskogo gosudarstvennogo radioteh-nicheskogo universiteta. 2022. no. ¹ 80. pp. 12-23. (in Russian).
Adaptive to interference wireless communication system based on multi-criteria synthesis of multi-position signals
A.A. Lisnichuk, e-mail: A.A.Lisnichuk@gmail.com
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: radio signal synthesis, software-defined radio, multi-criteria optimization, noise immunity.
Abstract
In practice, the operation of various radio communication systems (RCS), including those based on software-defined radio (SDR), is carried out under the influence of various types of radio interference: narrow-band, structural, bandpass, impulse, as well as their combinations. The quality indicators of RCS (including noise immunity) are significantly affected by the type of signals used and the characteristics of their processing devices. Existing software-defined radio systems are capable of reconfiguring signal parameters by varying the carrier frequency, radio transmitter power, as well as coding and modulation methods [1, 2]. This approach does not allow satisfying the needs of modern RCS in terms of multi-layered noise immunity of radio channels, i.e. ensuring the secrecy and noise immunity of radio links at various stages of formation, transmission and detection of signals [3, 4]. In addition, SDR systems may consider a frequency band unsuitable for transmitting information in the presence of even narrow-band interference, which in turn generally reduces the efficiency of using free spectrum sections.
In conditions of a limited frequency resource, it is advisable to synthesize radio signals to adapt SDR systems to interference when using, among other things, non-standard types of modulation. Optimization by a single quality indicator leads to uncontrolled deterioration of other indicators, therefore, for more efficient use of radio channel resources, it is advisable to apply multi-criteria signal synthesis.
With the consistency of the used coding and modulation procedures, according to a certain criterion, signal-code constructions are obtained, which provide additional improvement in the characteristics of the RCS.
These procedures have their own characteristics, advantages and disadvantages. A comparative analysis of the synthesized radio signals of different positioning has been carried out in the interests of adapting RCS to the current interference environment. When choosing the positioning of the synthesized radio signals in order to adapt the RCS to the interference environment, it is advisable to use a multi-criteria approach that takes into account at the current time: noise immunity to the action of AWGN and signal-to-interference conditions, the required hardware costs for signal synthesis, as well as the implemented compromise on other important quality indicators (energy efficiency, out-of-band radiation, correlation characteristics).
At the same time, the development of a unified block diagram of adaptive software-defined generator and detector of radio signals, corresponding to the developed procedures for multi-criteria signal synthesis and signal-code structures [3, 5, 6], is paramount importance. This is necessary for the implementation of a universal transceiver that covers a relatively wide class of radio signals that provide effective adaptation to interference under various external conditions.
References
1. Mitola J. Cognitive radio for flexible mobile communications // Mobile Multimedia Communications, 1999. (MoMuC '99) 1999 IEEE International Workshop. – 1999. – P. 3–10.
2. Hu F., Chen B., Zhu K. Full spectrum sharing in cognitive radio networks toward 5G: A survey //IEEE Access. 2018. vol. 6. pp. 15754-15776.
3. Lisnichuk A.A., “Multi-criteria synthesis procedure of DSSS signals for cognitive radio systems adaptation to complex interference environment,” Vestnik RGRTU, No. 66-1, 2018, pp. 9-15. (In Russ.). DOI: 10.21667/1995-4565-2018-66-4-1-9-15
4. Lisnichuk À.À. The procedure for multi-criteria synthesis of OFDM radio signals to reduce the crest factor and increase the structural secrecy of information transmission systems // Vestnik RGRTU. 2021. ¹ 77. p. 17-28. (In Russ.). DOI: 10.21667/1995-4565-2021-77-17-28
5. Kirillov S.N., Lisnichuk A.A., “The multi-criteria synthesis of signal-code sequence based on dependent signals to adapt data communication radio system to narrow-band interference,” Vestnik RGRTU, No. 4, 2017, pp. 3-12. (In Russ.).
6. Lisnichuk A.A., Kirillov S.N., “Analysis of cognitive radio systems characteristics adapting to narrow-band interference effect based on synthesized four-position radio signals,” Vestnik RGRTU, No. 66-1, 2018, pp. 3-8. (In Russ.). DOI: 10.21667/1995-4565-2018-66-4-1-3-8
7. S. N. Kirillov, A. A. Lisnichuk, “Multi-criteria signal synthesis procedure for adapting cognitive radio systems to the influence of interfering factors in the Arctic,” IOP Conf. Series: Earth and Environmental Science. Vol. 302, No. 1, p. 012059. DOI: 10.1088/1755-1315/302/1/012059
8. Sosulin Yu. G., Kostrov V. V., Parshin Yu. N. Estimated-correlation processing of signals and noise compensation. M: Radio engineering. 2014. 632 p. (In Russ.).
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10. S. N. Kirillov, A. A. Lisnichuk, and others. Multi-criteria approach to the choice of coding procedure for telemetric radio signals of complex technical objects // Vestnik RGRTU. 2021. ¹75. p. 3-14. (In Russ.).
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Improving interference immunity of radio systems using a modified phase adaptation algorithm
Yury Parshin, e-mail: parshin.y.n@rsreu.ru
Bui Quoc Vuong, e-mail: herapkm@gmail.com
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: interference suppression, adaptation, phase adaptation algorithm.
Abstract
The article examines algorithms for suppressing broadband interference by forming nulls in the radiation pattern of an antenna array in the direction of the incoming interference. It is known that such interference suppression methods require repeated measurements of interference power at the array output and multiple phase adjustments of antenna elements. These abrupt phase changes introduce distortions in the radiation pattern and create new peaks in the spectral power density of narrowband interference and signals. These adverse effects make it difficult the detection of useful signals in the spectral domain.
The article investigates the impact of broadband interference suppression algorithms on the spectral characteristics of narrowband interference and proposes a modified method for broadband interference suppression, testing its effectiveness.
In the modified interference suppression algorithm based on Shchapov Y.M.'s interference suppression algorithm, the values of terminal phases are selected from a set of optimal phases through specific adaptation cycles. New initial phases are set before each adaptation cycle. Initial phase values can be random or uniformly distributed with a predefined step.
The simulation results presented in the article show that during the phased adaptation of the antenna radiation pattern for broadband interference suppression, distortion of the narrowband interference spectrum occurs, leading to the appearance of spectral peaks at certain frequencies and an increase in the spectral level between them. The positions of these peaks depend on the interference measurement time, the number of antenna array elements, and the number of adaptation cycles. By tuning adaptation parameters, a balance between narrowband interference suppression and preserving valuable signals can be achieved.
The implementation of the modified algorithm contributes to aligning the output interference power towards the global minimum. Furthermore, the improvement compared to the basic algorithm amplifies with an increase in the number of adaptation cycles, resulting in a gain of 5...7 dB.
References
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4. Maltsev A. A., Zimina S. V. Spectral-correlation characteristics of the output signal of adaptive antenna arrays considering fluctuations of the weight vector // Radio Engineering and Electronics. 2001. Vol. 46. No. 11. Pp. 1350–1355.
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7. Parshin Yu. N., Gusev S. I. Determination of the optimal spatial structure of the signal processing system by the criterion of maximum likelihood // Bulletin of the Ryazan State Radio Engineering Academy. Vol.2. – Ryazan: RSREA. 1997. Pp. 5–11.
8. Parshin Yu. N., Gusev S. I. Formation of zeros of the antenna array radiation pattern by the maximum likelihood method // Bulletin of the Ryazan State Radio Engineering Academy. Issue3. Ryazan: RSREA. 1997. Pp. 9–15.
9. Parshin Yu. N., Lavrov A. M., Gusev S. I. Synthesis of robust spatial structures of radio systems using regularization // Bulletin of the Ryazan State Radio Engineering Academy. Issue 6. Ryazan: RSREA. 2000. Pp. 11–14.
10. Parshin Yu. N., Grachev M. V. Multi–stage reconfigurable signal processing in a spatially distributed radio system // Bulletin of the Ryazan State Radio Engineering University. Ryazan: RSREU. 2019. No. 67. Pp. 3–10.
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Analysis of multichannel detectors multi-frequency signals
D.I.Popov, e-mail: adop@mail.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: detection algorithm, analysis, Doppler phase, multi-frequency signal, block diagrams, radial velocity of the target, detection characteristic.
Abstract
Based on the correlation properties and the above algorithms for detecting multi-frequency radar signals, the analysis of the detection characteristics of multi-channel Doppler frequency detection systems for multi-frequency signals for various types of interperiod processing (optimal or quasi-optimal) in frequency channels is carried out.
The multichannel construction of systems when detecting a target at an unknown speed leads to separate detection in each frequency channel. The use of the matrix eigenvalue method made it possible to transform the characteristic function of the output (decisive) statistics to a form convenient for integration and obtain calculated expressions for the probabilities of false alarm and correct detection, with the help of which the desired detection characteristics are determined.
In particular, the gains in the signal-to-noise threshold ratio of the multi-frequency signal detection system, invariant in each frequency channel to Doppler phase shifts, are established in comparison with the known detection system and in comparison with the multi-channel Doppler frequency system. At the same time, energy gains are achieved in comparison with single-frequency interperiod processing systems.
The analysis of the effectiveness of optimal systems makes it possible to establish the maximum detection capabilities of the target signal for this class of systems. A comparative analysis of multichannel detection systems shows that the proposed quasi-optimal detection system based on single-channel coherent accumulation, although inferior in threshold signal-to-noise ratio to the optical system, but unlike it is technically feasible.
References
1. Skolnik M.I. Introduction to Radar System, 3rd ed., New York: McGraw-Hill, 2001. – 862 p.
2. Richards M.A., Scheer J.A., Holm W.A. (Eds.). Principles of Modern Radar: Basic Principles. New York: SciTech Publishing, IET, Edison. 2010. – 924 p.
3. Melvin W. L., Scheer J.A. (Eds.). Principles of Modern Radar: Advanced Techniques. New York: SciTech Publishing, IET, Edison, 2013. – 846 p.
4. Radar Handbook / Ed. by M.I. Skolnik. 3rd ed. McGraw–Hill, 2008. 1352 p.
5. Popov D.I. Adaptacija nerekursivnyh rezhektornyh fil'trov // Izvestija vuzov. Ra-diojelektronika. 2009. vol. 52. no. 4. P. 46-55. (in Russian).
6. Popov D.I. Autocompensation of the Doppler phase of clutter // Cifrovaja obrabotka signalov. 2009. no 2. pp. 30–33. (in Russian).
7. Popov D.I. Avtokompensacija doplerovskoj fazy mnogochastotnyh passivnyh pomeh // Vestnik Rjazanskogo gosudarstvennogo radiotehnicheskogo universiteta. 2018. no. 65. pp. 32–37.
8. Popov D.I. Adaptive suppression of clutter // Cifrovaja obrabotka signalov. 2014. no. 4. pp. 32-37. (in Russian).
9. Popov D.I. Adaptivnije regektornjie filtrij kaskadnogo tipa // Cifrovaya obrabotka signalov. 2016. no. 2. pp. 53-56. (in Russian).
10. Popov D.I. Adaptive notch filter with real weights // Cifrovaya obrabotka signalov. 2017. no. 1. pp. 22-26. (in Russian).
11. Popov D.I. Optimizacja nerekursivnjih regektornjie filtrov s chastichnoj adaptaciej // Cifrovaya obrabotka signalov. 2018. no. 1. pp. 28-32. (in Russian).
12. Popov D.I. Optimizacija rezhektornyh fil'trov po verojatnostnomu kriteriju // Cifrovaja obrabotka signalov. 2021. no. 1. P. 55-58. (in Russian).
13. Kuz'min S.Z. Cifrovaja radiolokacija. Vvedenie v teoriju (Digital radar. Introduction to Theory). Kiev: KViC, 2000. 428 p. (in Russian).
14. Cifrovaja obrabotka signalov v mnogofunkcional'nyh radiolokatorah. Metody. Algoritmy. Apparatura: monografija (Digital signal processing in multifunctional radars. Methods. Algorithms. Equipment: monograph) / pod red. G.V. Zajceva. M.: Radiotehnika, 2015. 376 p. (in Russian).
15. Klochko V.K., Kuznecov V.P., Levitin A.V. i dr. Algoritmy opredelenija koordi-nat dvizhushhihsja celej na baze mnogokanal'noj doplerovskoj RLS // Vestnik Rjazanskogo gosudarstvennogo radiotehnicheskogo universiteta. 2015. no. 53. pp. 3-10. (in Russian).
16. Klochko V.K., Kuznecov V.P., Vu Ba Hung. Ocenivanie parametrov radiosignalov ot podvizhnyh malovysotnyh ob#ektov // Vestnik Rjazanskogo gosudarstvennogo radioteh-nicheskogo universiteta. 2022. no. ¹ 80. pp. 12-23. (in Russian).
17. Popov D.I., Belokrylov A.G. Sintez obnaruzhitelej-izmeritelej mnogochastotnyh signalov // Izvestija vuzov. Radiojelektronika. 2001. v. 44. no. 11. pp. 33-40. (in Russian).
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Adaptation of codecs of speech signals on the basis of theorem V.A. Kotelnikov and modifications of the Khurgin-Yakovlev algorithm to noise in the
communication channel
Dmitriev V.T., e-mail: vol77@rambler.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: speech signals, primary codec, software-defined systems, codec adaptation, reception and transmission of information, signal processing, acoustic noise, interference, communication channel.
Abstract
An algorithm for adapting primary codecs to noise and distortion in a communication channel is proposed. Algorithms of adaptation of primary codecs of speech signals are considered. Adaptation algorithms are proposed under the influence of interference in the communication channel in order to ensure the optimal ratio of the quality of the restored speech at the minimum transmission rate based on the theorem of V.A. Kotelnikov and the proposed modification of the Khurgin-Yakovlev algorithm.
It is shown that the use of a modification of the Khurgin-Yakovlev algorithm with separate coding of signal samples and derivative allows to increase the quality of the restored speech by 0.5 ... 1.2 points according to GOST R 50840-95 compared to similar non-adaptive codecs based on V.A. . Kotelnikov or the possibility of reducing the required transmission rate by 15 ... 30% for software-defined radio systems for receiving, transmitting and processing information.
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11. Kirillov S.N., Dmitriev V.T., D.E. Krysyaev, S.S. Popov Investigation of the quality of transmitted speech information with various combinations of source and communication channel coding algorithms under interference conditions. Vestnik RGRTU 2008 No. 1 (Issue 23). - PP. 53-56.
12. GOST R 50840-95. Speech transmission over communication paths. M.: Gosstandart of Russia, 1995. - 180 p.
13. Dmitriev V.T., Konstantinova Algorithm for a comprehensive assessment of the quality of speech in a communication channel. // Vestnik RGRTU. 2016. No. 56 - pp. 42-47.
14. Kirillov S.N., Dmitriev V.T. A complex algorithm for objective assessment of the quality of a decoded speech signal under the action of acoustic interference. // Proceedings of SPIIRAS 2018. No. 1. - pp. 34 -55.
15. Kirillov S.N., Dmitriev V.T., Kartavenko Ya.O. Algorithm for an objective assessment of the quality of a decoded speech signal based on the change in the spectral dynamics of the critical bands of the spectrum. Vestnik RGRTU. 2011. No. 37. pp. 3-7.
16. Dmitriev V.T. Noise immunity of speech codecs based on the Khurgin-Yakovlev algorithm / Vestnik RGRTA No. 12, 2003 - pp. 133-136.
17. Kirillov S.N., Dmitriev V.T. Stability of primary codecs of speech signals based on the representation of Khurgin-Yakovlev to the action of acoustic noise.// Vestnik RGRTU. 2019. No. 3 - pp.17-25.
Underwater wireless optical channel with bi-color data transmission scheme
Dmitriev V.T., , e-mail: vol77@rambler.ru
Aronov L.V., e-mail: aronov.l.v@rsreu.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: underwater optical wireless communication channel, optical wireless communication, free space optic, underwater communication, optical communication line.
Abstract
The article proposes to use a two-color data transmission scheme based on NDB4116 and NDA4216 semiconductor laser LEDs in an underwater wireless optical channel to increase the range. Computer modeling has shown that the gain in distance ranges from 1.6% to 5.6% for given initial data, however, a twofold increase in throughput is possible. It is proposed to use this property to increase the rarefaction of video data streams transmitted over an underwater wireless optical channel, and also to use an optical transmitter based on a 473 nm laser as a service or reverse low-speed channel. Brief recommendations are given to improve the efficiency of the proposed scheme.
The results of the study conducted in this article show that reducing the speed does not provide a fundamental gain in distance, except that the characteristics of a channel with a split video stream have a relationship in clear and turbid water. However, it is possible to use both branches of the two-color channel to increase the data transfer rate and, as is done in China, increase the resolution of professional video images. In combination with other methods of increasing the communication range, for example, using noise-resistant coding, this method may be more effective, but this issue requires separate research.
In the case of low water turbidity, the 473 nm channel, close to the “clear sea” type, can play the role of a service channel for transmitting additional telemetry and service information, and it is also possible to use it as a reverse service channel. This requires minimal hardware costs when introducing light filters, which also leads to a reduction in the energy budget by approximately 0.7 dB. However, as for the two-color transmission scheme, in its modern form it is capable of increasing throughput, but not range. On the other hand, for muddy water, a twofold increase in the capacity of an underwater wireless optical data transmission channel is possible.
References
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The model with calibration a pulse reflectometric level gauge using reference marks
Koryachko V. P., e-mail: koryachko.v.p@rsreu.ru
Rumyancev S. S., e-mail: R0806rus@yandex.ru
Aronov L.V., e-mail: aronov.l.v@rsreu.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: reflectometric level gauge, pulsed reflectometer, mathematical model, nuclear power plant, computer model, SimInTech.
Abstract
In order to control the coolant level in the primary circuit of a nuclear power plant, it is proposed to use pulsed reflectometric level gauges. In this article, a method for calibrating a sensitive element based on reference marks is substantiated, which makes it possible to level the influence of temperature from 277 K to 523 K and pressure from 0.1 to 25 MPa. Various designs of labels are considered, their advantages and disadvantages are described. A computer simulation of a pulsed reflectometric level gauge was performed using the SimInTech dynamic simulation environment. The simulation results, including the appearance of the reflectogram, correspond to theoretical assumptions. The resulting model allows optimization to select the parameters of the fiducial marks, and can be extended to study additional inhomogeneities in the sensitive element of a pulsed reflectometric level gauge.
An extended model of the microwave path of a pulsed reflectometric level meter was obtained for measuring the coolant level in the primary circuit of a nuclear power plant, which allows taking into account additional inhomogeneities. The calibration method based on reference marks makes it possible to correct the error in measuring the coolant level in the primary circuit of a nuclear power plant, which arises due to changes in the relative dielectric constant as a result of temperature fluctuations from 277 to 523 K and pressure from 0.1 to 25 MPa . The computer model in the dynamic modeling environment SimInTech allows you to solve problems related to optimization of parameters. The disadvantages include the fact that the impulse response of sections of the microwave path and reflections on inhomogeneities are not taken into account, however, for analysis and decision-making in a first approximation, the existing capabilities of the model are sufficient, and the flexibility and adaptability of the SimInTech environment allows you to expand and adapt model for additional tasks, taking into account new parameters.
References
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9. Vasiliev E.P. Analysis of methods for modeling microwave devices using the example of a band-pass filter with an extended stop band / E.P. Vasiliev // Bulletin of RGRTU. Ryazan. RGRTU. 2020. Issue. 2 (72). pp. 62-70.
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11. Kartashov B.A. Environment for dynamic modeling of technical systems SinInTech: Workshop on modeling automatic control systems [Text] / B.A. Kartashov, E.A. Shabaev, O.S. Kozlov, A.M. Shchekaturov - M.: DMK Press, 2017. – 424 p.
Exponential relaxation signal processing in spectroscopic methods for studying semiconductor barrier structures
Ermachikhin A.V., e-mail: al.erm@mail.ru
Trusov E.P., e-mail: eptrusov@yandex.ru
Gudgev. V.V., e-mail: valerygudzev@yandex.ru
Zubkov M.V., e-mail: mihailzubkow@yandex.ru
Litvinov V.G., e-mail: vglit@yandex.ru
The Ryazan State Radio Engineering University (RSREU), Russia, Ryazan
Keywords: signal processing, deep level transient spectroscopy, exponential signal, computer processing.
Abstract
The paper discusses the problems of a physical experiment related to the practical implementation of the method of deep level transient spectroscopy designed to study and control physical processes associated with the electronic levels recharge in semiconductor barrier micro- and nanostructures. The problem concerns the measurement and processing of a noisy signal that depends on temperature and varies exponentially.
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