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2024 Systems of Signal Synchronization, Generating and Processing in Telecommunications, SYNCHROINFO 2024

作者： Djigan, V.I. Institute for Design Problems in Microelectronics of Ras Moscow Department of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350373448

This paper presents an Adaptive Antenna Array (AAA) which is able to suppress the signals of the interferences at its output, to receive the informational signal under the low Signal-to-Noise Ratio (SNR) conditions and to steer its beam (the radiation pattern main lobe) towards the source of the informational signal even if the angular location of the source is initially unknown. It is presented the AAA architecture. The architecture is compared with other architectures of the AAA that are able or not able to operate under the same conditions. The ability to operate in low SNR condition is ensured because of the preprocessing of the AAA channel signals by the correlators or by the matched filters. Such preprocessing is possible if the received informational signal is a Pseudo Random Sequence (PRS). Using the signal as a desired one also allows to use the least squares criterion adaptive algorithms for the AAA weights calculation. This ensures the interferences suppression and the AAA beam steering simultaneously. The considered AAA is able to process the modulated PRS. This ability is provided by the usage of a slicer (like in a decision directed equalizer) which produces the desired signal from the AAA output signal during the steady-state operation. Two versions of the algorithms for the AAA weights calculations are presented. They are the Recursive Least Squares (RLS) adaptive filtering algorithms based on the inverse QR decomposition. Simulation results demonstrate the performance and the efficiency of the considered AAA. © 2024 IEEE.

关键词： Signal to noise ratio

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Espresso-like Iterative Algorithm for Three-Level Logic Minimization

Espresso-like Iterative Algorithm for Three-Level Logic Mini...

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2023 Seminar on Networks, Circuits and Systems, NCS 2023

作者： Stempkovsky, Alexander L. Telpukhov, Dmitry V. Nadolenko, Vladislav V. Institute for Design Problems in Microelectronics of RAS Moscow Russia

ISBN: (纸本)9798350370386

Minimization is an important part of any logic synthesis algorithm. Espresso algorithm can be used as a first step for global two-level minimization. Then factorization is performed to obtain multi-level structure and various local optimization algorithms are applied. This paper presents a new algorithm called Xpresso to replace Espresso in described synthesis flow. It works with three-level logic circuit structure in a form of DNF with an extra layer of XORs. Such structure allows more compact representation than pure DNF while keeping global minimization feasible. Proposed minimization algorithm consists of three iterative Espresso-like steps: expand, irredundant and reduce, tweaked to work with three-level structure. Computational complexity stays mostly at original Espresso's level with most expensive part of expand being transferred to GPU. Experimental results are provided for combinational logic circuits from LGSynth'91 benchmark. Xpresso's outputs are compared to those of Espresso by operation count and a few other metrics. © 2023 IEEE.

关键词： Logic Synthesis

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Signal Source Angular Location Tracking Algorithm 26

Signal Source Angular Location Tracking Algorithm

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26th International Conference on Digital Signal Processing and its Applications, DSPA 2024

作者： Djigan, Victor I. Institute for Design Problems in Microelectronics of Ras Department of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350361728

This paper presents an algorithm of the signal source angular location tracking. The tracking is carried out by means of an antenna array. Traditional angular tracking is based on the usage of a monopulse (sum and difference) architecture which combines the output signals of the directional antennas (with mechanical or electronic steering). This requires the usage of a few antennas and a combiner of the antenna output signals. The algorithm, presented in this paper, allows to find the signal source angular location using only one directional antenna that is the antenna array. It is assumed the usage of the antenna array with the digital beamforming. However, the analog phased array can be used as well. This is because the algorithm is based on the processing of the antenna array output signal estimates after the changing (perturbations) only the phases of the array channel signals. This changing can be done by means of the phased shifters in a phased array or by means of the complex-valued weights with the unity absolute values in an antenna array with the digital beamforming. The paper considers the usage of the algorithm in a linear antenna array. To improve the signal-to-noise ratio, the array output samples are processed by a correlator or a matched filter. For this reason, the measured signal must be a pseudo noise sequence. The paper describes the proposed algorithm and the simulation results that confirm the algorithm's operation and demonstrate its efficiency. © 2024 IEEE.

关键词： Beamforming

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Adaptive Processing of Matched Filter Output Signals in Antenna Array 26

Adaptive Processing of Matched Filter Output Signals in Ante...

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26th International Conference on Digital Signal Processing and its Applications, DSPA 2024

作者： Djigan, Victor I. Institute for Design Problems in Microelectronics of Ras Department of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350361728

An Adaptive Antenna Array (AAA) is presented in this paper. The least squares criterion adaptive algorithms are used for the array weights calculation. The informational signal of the AAA is a periodic pseudo random sequence, which is hidden by the noise of the array channels. Such sequences are often used in modern radar, navigation and communication systems. The Matched Filters (MF) or the correlators are used for the processing of the AAA channel signals and this enables the usage of the adaptive algorithms based on the least squares criterion. The output signals of the MF are the cross-correlation functions of the AAA channel signals and the pseudo random sequence. The AAA weights calculation algorithm processes the periodic samples of the maximal values of the MF output signals and processes the error signal between the output and desired signals of the array. The desired signal is also composed using the samples of the maximal values of the auto-correlation function of the pseudo random sequence. The calculation of the AAA weights is provided by the Matrix Inversion Lemma Recursive Least Squares algorithm and its two computationally efficient modifications. The simulation demonstrates that the AAA can suppress the interfering signals and can track the informational signal source angular location simultaneously even if the location is initially unknown. This allows to use the AAA for the signal receiving from a moving source in the presence of the interfering signals. © 2024 IEEE.

关键词： Matched filters

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Measuring Far-Field Radiation Patterns of Digital Beamforming Antenna Arrays

Measuring Far-Field Radiation Patterns of Digital Beamformin...

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2024 Systems of Signals Generating and Processing in the Field of on Board Communications, SOSG 2024

作者： Djigan, V.I. Department of Integrated Circuits Design Methodology Institute for Design Problems in Microelectronics of RAS Moscow Russia

ISBN: (纸本)9798350383614

A method of the antenna array far-field Radiation Pattern (RP) measurement is considered. This method is designed for the usage with the receiving Digital Beamforming Antenna Arrays (DBAA). Such type of antenna arrays typically does not have a radiofrequency output. Hence, the standard methods of the RP measurement, based on the radiation and the reception of the monochromatic probing signal, cannot be used for the DBAA RP measurement. The proposed method assumes the radiation of a probing signal modulated by a pseudo-noise sequence and the base-band processing of the DBAA output signal by means of a matched filter or a correlator. The paper presents the description of the measurement setup and the mathematical explanation of the measuring procedure. It has been shown that the accuracy of the RP measurement depends on the Signal-to-Noise Ratio (SNR) at the outputs of the DBAA channel receivers, the number of the array channels and the number of the pseudo-noise sequence symbols. The accuracy increases on 3 dB each time as the number of the array antennas or the pseudo-noise sequence symbols is doubled. This result is confirmed by the simulation of the RP measurement of the eight and the sixteen channel linear antenna arrays with the usage of the maximum length pseudo-noise sequence of 1023 and 2047 symbols. ©2024 IEEE.

关键词： Beamforming

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Algorithm of Signal Source Angular Location Searching and Tracking by Two-Dimensional Rectangular Array

Algorithm of Signal Source Angular Location Searching and Tr...

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2024 Wave Electronics and its Application in Information and Telecommunication Systems, WECONF 2024

作者： Djigan, V.I. Institute For Design Problems In Microelectronics Of Ras Department Of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350364989

An algorithm of searching and tracking the angular location of a signal source is presented. It is designed for the usage in a two-dimensional equidistant rectangular receiving antenna array. This algorithm uses symmetric perturbations of the array phase distribution on a fixed phase value and uses estimations of the signal values at the array output after these perturbations. It is required to make four such the perturbations in a two-dimensional array or to make two such the perturbations in a one-dimensional linear array. The array has to be a symmetric one for the algorithm usage. This means, that the phase distribution over the array aperture has to be an odd symmetric relatively the array phase center. Because of the phase perturbation, the algorithm can be used in the analog arrays with the phase only control or in the digital beamforming arrays with the complex-valued weights control. To improve the algorithm accuracy, it is suggested to use a correlator or a matched filter to estimate the array output signals. The estimation can be used if the array receives a pseudo random signal. Such the signals are widely used as the informational ones in a number of modern radio systems. Mathematical details of the proposed algorithm are presented. Simulation demonstrates the performance and the efficiency of this algorithm. © 2024 IEEE.

关键词： Matched filters

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Solving the FPGA Routing Problem Using the Model of an Extended Mixed Routing Graph

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Russian microelectronics 2023年第7期52卷 682-689页

作者： Zapletina, M.A. Institute for Design Problems in Microelectronics Russian Academy of Sciences Moscow124365 Russia

Abstract: An architecture-aware extended mixed routing graph model allows describing the features of the routing resources of modern field-programmable gate arrays (FPGA). It can be used to solve the tasks of interconnections routing as part of an FPGA layout synthesis flow. In this work, an architecture-aware extended mixed routing graph model is considered. Two modifications are proposed for the basic method of automatic routing that is the classical Pathfinder algorithm adapted to a mixed routing resources graph. The first modification is based on the idea of a directed search on the graph model using data on the spatial and geometric characteristics of the basic FPGA chip, while the second one combines a directed search strategy with consideration of a preliminary routing congestion assessment based on the results of the placement procedure. It has been demonstrated that the proposed modifications make it possible to accelerate the basic method convergence by an average of 50.6 and 38.6%, respectively. While maintaining the routability of IWLS’2005, ISCAS’89 and LGSynth’89 benchmark suits, the use of only directed search led to an improvement in the timing characteristics of test circuits implementations by 5.2% on average, and its use together with an assessment of congestion before the start of routing, to these characteristics improvement by 9.3% on average relative to the results of the basic Pathfinder method. © Pleiades Publishing, Ltd. 2023. ISSN 1063-7397, Russian microelectronics, 2023, Vol. 52, No. 7, pp. 682–689. Pleiades Publishing, Ltd., 2023. Russian Text The Author(s), 2022, published in Izvestiya Vysshikh Uchebnykh Zavedenii, Elektronika, 2022, Vol. 27, No. 6, pp. 774–786.

关键词： Field programmable gate arrays (FPGA)

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Dynamics of the Vector of Magnetization in a Free Layer of a Spin Valve with Planar Anisotropy under the Action of Arbitrarily Directed Magnetic Fields

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Bulletin of the Russian Academy of Sciences: Physics 2023年第3期87卷 310-317页

作者： Iusipova, Iu. A. Skidanov, V.A. Institute for Design Problems in Microelectronics Russian Academy of Sciences Moscow124365 Russia

Abstract: Modeling is done for the dynamics of the vector of magnetization in the free layer of a spin valve with planar layer anisotropy in arbitrarily directed magnetic fields. Bifurcation analysis of the dynamic system, the conditions for changing the type of singular points are established, and the dynamics of magnetization is classified. © 2023, Allerton Press, Inc.

关键词： Magnetization

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Adaptive Antenna Array for Low Signal-to-Noise Ratio Operation

Adaptive Antenna Array for Low Signal-to-Noise Ratio Operati...

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2023 Antennas design and Measurement International Conference, ADMInC 2023

作者： Djigan, Victor I. Institute for Design Problems in Microelectronics of RAS Department of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350326765

The adaptive antenna array which operates in the low signal-to-noise ratio (SNR) is presented. In this scenario, the Minimum Mean Squares Error (MMSE) criterion adaptive algorithms cannot be used for the array weight calculation. If the angular location of the signal source is known, it is possible to use the linearly constrained adaptive algorithms. However, this location is often unknown or it is changed if the signal source or the array is moving. At the same time, if the informational signals are the pseudo-noise sequences, they can be pre-processed by the matched filters or by the correlators. In this case the informational signal at the devices output becomes above the noise (the SNR is increased) and the MMSE criterion algorithms can be used for the calculation of the adaptive array weights. The adaptive array based on this criterion is able to suppress the interference signals. Besides, it is also able to steer the beam in the direction of the informational signal source and to track the source. The computational procedures of the two Recursive Least Squares algorithms which process the matched filter output signals for the calculation of the adaptive array weights are considered. One of these algorithms uses the complex-valued arithmetic and other one uses the real-valued arithmetic. The simulation demonstrates that the real-valued arithmetic algorithm has about 3 dB better cancellation of the interference signals at the adaptive array output and about two times shorter transient response. © 2023 IEEE.

关键词： Adaptive algorithms

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Simplified Fast Affine Projection Algorithm in Echo Cancellation Tasks

Simplified Fast Affine Projection Algorithm in Echo Cancella...

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2023 Wave Electronics and its Application in Information and Telecommunication Systems, WECONF 2023

作者： Djigan, V.I. Institute for Design Problems in Microelectronics of RAS Department of Integrated Circuits Design Methodology Moscow Russia

ISBN: (纸本)9798350348293

This paper considers an adaptive echo canceller which can be used in tasks of acoustic or electrical echo cancellation. The solution of these tasks usually requires the usage of the adaptive filters with a large number of weights. This means that a lot of computational resources of hardware or software are required for the echo canceller implementation. The usage of the Fast (computationally efficient) Affine Projection (FAP) adaptive filtering algorithm ensures the adaptive filter functional efficiency and complexity tradeoff in the echo cancellation tasks. The algorithm consists of two groups of calculations: a fast calculation of the adaptive filter error and a fast calculation of the normalizing matrix and its inversion. The second group is based on the usage of some calculations adopted from the sliding window Fast Recursive Least Squares adaptive filtering algorithms. However these calculations are potentially unstable. The given paper presents a simplified stable version of the multichannel FAP algorithm. The simplification is achieved due to the diagonalization of the normalizing matrix that ensures a simple procedure of direct calculation of this matrix and its inversion. If the echo signal is noisy (and that what always happens in our real world) then the original and the simplified FAP algorithms demonstrate about the same performance. The simulation of the two-channel acoustic echo cancellers confirms this statement. © 2023 IEEE.

关键词： Adaptive filters

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