Brovkin Andrey Aleksandrovich

Scopus Publications

MCS MAP FOR LINK-LEVEL SIMULATION OF TWO-USER PD-NOMA SYSTEM
Yakov Kryukov, Dmitriy Pokamestov, Andrey Brovkin, Artem Shinkevich, Georgiy Shalin
Proceedings on Engineering Sciences, 2024
Power Domain Non-Orthogonal Multiple Access (PD-NOMA) is a promising technique for future wireless networks. Currently, the growing number of researchers are addressing PD-NOMA issues. The great number of known results are based on the Shannon capacity theorem, assuming infinite code block length. However, they cannot be achieved in practice when modulation and coding schemes (MCS) with finite code block length are used. To solve this problem, we propose an approach which allows utilizing LTE MCSs in the link-level simulation of PD-NOMA. In this paper, we present an adaptive MCS map for a PD-NOMA system with two users, considering non-perfect Serial Interference Cancelation (SIC). In addition, we have developed a map for power allocation coefficients (PAC). The max-sum rate criterion and 10%-Block Error Rate constraint are utilized. The MCS and PAC maps allow access point to jointly and adaptively select MCS parameters for the users depending on their SNR values. The proposed MCS maps can be used in a link-level simulation of the PD-NOMA system to near-practical performance.
Comparison of PD-NOMA Capacity with Conventional and Joint Gray-Mapping
Andrey A. Brovkin, Yakov V. Kryukov, Dmitriy A. Pokamestov, Artem S. Shinkevich, Georgiy N. Shalin, Dmitriy E. Ilinskiy
International Conference of Young Specialists on Micro Nanotechnologies and Electron Devices Edm, 2024
The paper compares two bit-mapping approaches for non-orthogonal multiple access with channel separation in power domain in a system with two users. In the first approach, bit mapping to modulation symbols is implemented independently for each user, and in the second approach, joint Gray-mapping is implemented. This allows for increasing the bit error rate performance of the user channel with a “strong” propagation channel and extending the range of acceptable values for power allocation. For this paper, we have constructed capacity maps that show the total spectral efficiency of channels depending on their channel states. The system model uses signal-code constructions combining quadrature amplitude modulation and polar codes. It is shown that the joint bit mapping allows for greater spectral efficiency under identical conditions. We have performed a computer simulation to evaluate the average spectral efficiency that was calculated in a system with one base station and 10 users, observing the planning strategy of max-min fair. The results demonstrate that the joint Gray-mapping makes it possible to increase the average spectral efficiency of the system by 3.3% compared with the independent mapping.
Evaluation of LDPC codes efficiency in channels with fading
Artem Shinkevich, Dmitriy Pokamestov, Yakov Kryukov, Georgiy Shalin, Andrey Brovkin, Eugeniy Rogozhnikov
E3s Web of Conferences, 2023
The article discusses the operation of communication systems using a low-density parity check codes in channels with multipath propagation. This class of codes has found wide application in modern communication and broadcasting systems and is one of the most effective in now. Some theoretical and practical issues of combating the effects arising from multipath propagation are presented. The description of the developed simulation model, channel codec, equalizer, and transmission channel is given. The channel encoder in the model is designed in accordance with the specifications for the 5G New Radio (5G NR) communication standard. The multipath parameters in the transmission channel correspond to the TDL models for 5G NR, with the exception of the Doppler shift, which is not taken into account in the simulation. In addition, there is additive interference in the channel. The decoding algorithm used was also described in detail. As a result of the study, the dependences of the bit error probability on the signal-to-noise ratio were obtained for the code rates 1/2 and 1/8, as well as for the system without coding. Based on the results obtained, it is possible to judge the correcting ability of this class of codes.
Differential properties of polar codes
Georgiy Shalin, Dmitriy Pokamestov, Yakov Kryukov, Artem Shinkevich, Andrey Brovkin, Eugeniy Rogozhnikov
E3s Web of Conferences, 2023
This paper discusses the features of polar coding as a differential encoder for a binary erasure channel. One of the modern methods of error-correcting coding is polar codes, which has great prospects in the development of current and future wireless communication systems. At the moment, polar coding is used only in fifth-generation systems. In this paper, a description of polar coding is presented, a description of a polar decoding algorithm capable of restoring messages with an error probability close to 1 is presented, and a general model of a binary channel with erasures is described. The channel model represents a fixed number of introduced errors, depending on the size of the transmitted message. The result of the study is the dependence of the bit-error ratio (BER) on the error probability for low, medium and high code rates, which illustrate the possibility of the polar coding algorithm to restore a message with a partially or completely inverse data stream.
Representation of ICI as AWGN in PD-NOMA System Model
Yakov V. Kryukov, Dmitriy A. Pokamestov, Andrey A. Brovkin
International Conference of Young Specialists on Micro Nanotechnologies and Electron Devices Edm, 2023
Power Domain Non-Orthogonal Multiple Access (PD-NOMA) is recognized as one of the most promising technologies for next-generation multiple access in future wireless networks. Such multiplexing leads to the controlled inter-channel interference (ICI) cancelled at the receiver. In reality, ICI is represented as quadrature amplitude modulated (QAM) symbols (or other modulation). However, the vast majority of research papers use signal models in which ICI is represented as the additive white Gaussian noise (AWGN) with the equivalent power. Yet, such a replacement is not fully equivalent, because it reduces the accuracy of signal decoding. This is a significant simplification of the system model, which results in an additional inaccuracy in obtaining a number of system characteristics. This paper presents an approach that allows solving this problem and representing ICI as AWGN by means of a coefficient without increasing the decoding error. It also describes an expression for calculating the coefficient obtained and its performance confirmed by simulation results.
Evaluation of noise immunity of multi-user mimo systems with imperfect channel estimation and other distortions
Artem Shinkevich, , Dmitry A. Pokamestov, Yakov V. Kryukov, Evgeny V. Rogozhnikov, Georgy N. Shalin, Andrey A. Brovkin, , , , , and
Radioelektronika Nanosistemy Informacionnye Tehnologii, 2023
The technology of multi-antenna MIMO (Multiple Input Multiple Output) systems is actively used in modern wireless communication systems. MIMO can enhance the performance of wireless data transmission systems, but their effectiveness depends on the transmission conditions. Ideal conditions are represented as a channel with a large number of possible signal propagation paths and an error-free estimation of its parameters. The estimation error significantly affects the performance of the beamforming algorithms used to mitigate inter-user interference in multi-user MIMO (MU-MIMO) systems. Spatial correlation of the channel results in a decrease in the number of independent information transmission streams. These factors can significantly reduce the performance of multi- antenna systems. For this reason, operating MIMO communication systems under non-ideal conditions is a topical issue. The paper examines the performance of various beamforming algorithms in such conditions. It describes the communication systems with MIMO, beamforming algorithms, and distorting effects. The paper includes a developed simulation model of the communication channel with MU-MIMO accounting for a variety of distorting factors. The results demonstrate the bit-error probability dependences for different simulation scenarios.
Performance Comparison of Decoders of Non-orthogonal Multiple Access Signals Considering Modulation and Coding Schemes from LTE Networks
Yakov V. Kryukov, , Dmitry A. Pokamestov, Andrey A. Brovkin, Evgeny V. Rogozhnikov, , , and
Radioelektronika Nanosistemy Informacionnye Tehnologii, 2022
A comparative analysis of the performance of SL-SIC (Symbol Level - Serial Interference Cancellation) and CWL-SIC (Codeword Level-SIC) decoders of PD-NOMA (Power Doman - Non-Orthogonal Multiple Access) baseband signals in a system with two users is presented. Real signal code constructs (SCC) from the 3GPP LTE (Long Term Evolution of 3rd Generation Partnership Project) communication standard are used. The performance of CWL-SIC achievable in practice in real systems for all possible designs of a group PD-NOMA signal consisting of different pair combinations of noise-immune SCCs has been obtained. With the help of mathematical modeling, weighting power coefficients are obtained that provide the maximum average performance of the group signal for two user channels. The high efficiency of the CWL-SIC and the expediency of its use in real systems, especially in conditions of low signal-to-noise ratio, are shown.
Scheduling PD-NOMA with Round-Robin, Equal-Rate and Proportional-Fair Strategies
Andrey A Brovkin, Yakov V. Kryukov, Dmitriy A. Pokamestov, Evgeniy V. Rogozhnikov, Georgiy N. Shalin, Artyom S. Shinkevich
2022 International Siberian Conference on Control and Communications Sibcon 2022 Proceedings, 2022
The paper discusses the distribution of radio resources for a hybrid communication system adaptively using orthogonal (OMA) and non-orthogonal (NOMA) multiple access, which is the power domain NOMA (PD-NOMA) method. The problem of radio resource allocation in PD-NOMA systems remains topical because the additional degree of freedom (power domain) significantly increases the number of possible approaches, and it is required to find the optimal approach among them. We offer our own approach to radio resource planning and compare it with the existing. Moreover, we use the Monte Carlo simulation to compare the OMA and the hybrid OMA/NOMA systems. The comparison criterion is the amount of transmitted traffic. For the hybrid system, there is a proprietary table of paired signal-code constructions proposed to jointly assign modulation and coding schemes (MCS) to NOMA users and carry out multiplexing in the power domain.
A simple proportional fair scheduling for downlink power domain non-orthogonal multiple access systems
Ya V Kryukov, A A Brovkin, D A Pokamestov, A S Kvashnina
Journal of Physics Conference Series, 2020
Currently, non-orthogonal multiple access technologies have gained high relevance in wireless multi-user broadband communications. Many papers have shown that non-orthogonal multiplexing can significantly increase the capacity of the system. Despite this, it technology is still far from practical implementation due to unresolved issues. One such issue is radio resource scheduling in communication systems using non-orthogonal multiple access which poses a high computational complexity and turns out to be a problem for a base station with a large number of users it serves. In our paper, we propose our own resource scheduling method for systems with non-orthogonal multiplexing using proportional fair strategy. This method allows for simultaneous resource scheduling in two segments – an orthogonal segment (time-frequency domain) and a non-orthogonal segment (power domain). To assess the effectiveness of the proposed method, we use the developed simulation model of resource scheduling for a communication system with a single cell. The effectiveness of the proposed scheduling method is confirmed by the simulation result, and its use allows achieving the proportional fair strategy implementation. In the final part, we use iterative simulation to compare the throughput of systems with orthogonal and non-orthogonal multiplexing using proposed proportional fair scheduler. The result of comparison showed that using the proposed proportional fair scheduling can increase the system capacity by an average of 28%. The results can be applied to create communication systems with different non-orthogonal multiple access implementations.
Analysis of the downlink channel estimation methods in communication systems with SCMA
Dmitriy Pokamestov, Yakov Kryukov, Evgeniy Rogozhnikov, Evgeniy Mishchenko, Andrew Brovkin
2nd International Conference on Electrical Communication and Computer Engineering Icecce 2020, 2020
Sparse Code Multiple Access (SCMA) is a nonorthogonal multiple access method that provides high bandwidth, noise immunity and a larger number of connections compared to traditional methods such as Orthogonal Frequency Division Multiple Access (OFDMA). One of the important problems that negatively affects the quality of communication is multipath propagation. To combat it, various equalization techniques are used, which provide for channel estimation by the receiver. In this paper, we consider three methods for estimating the downlink transmission channel for communication systems with SCMA. The first method is an assessment by reference (pilot) signals, which is classical and is widely used in modern telecommunication systems. The second method under consideration is the assessment of the regenerated information symbols. The third is a blind channel estimate. Algorithms are proposed for all three methods, and mathematical modeling is performed. The results of the dependences of the mean square error and bit error on the signal-to-noise ratio are obtained.
Power and frequency scheduling using equal throughput strategy in pd-noma systems
Ya. V. Kryukov, D. A. Pokamestov, A. A. Brovkin, E. V. Rogozhnikov
Advances in Intelligent Systems and Computing, 2020