Nested code sequences of Barker — Mersenne — Raghavarao

Author(s):  
M. B. Sergeev ◽  
V. A. Nenashev ◽  
A. M. Sergeev

Introduction: The problem of noise-free encoding for an open radio channel is of great importance for data transfer. The results presented in this paper are aimed at stimulating scientific interest in new codes and bases derived from quasi-orthogonal matrices, as a basis for the revision of signal processing algorithms.Purpose: Search for new code sequences as combinations of codes formed from the rows of Mersenne and Raghavarao quasi-orthogonal matrices, as well as complex and more efficient Barker — Mersenne — Raghavarao codes.Results: We studied nested code sequences derived from the rows of quasi-orthogonal cyclic matrices of Mersenne, Raghavarao and Hadamard, providing estimates for the characteristics of the autocorrelation function of nested Barker, Mersenne and Raghavarao codes, and their combinations: in particular, the ratio between the main peak and the maximum positive and negative “side lobes”. We have synthesized new codes, including nested ones, formed on the basis of quasi-orthogonal matrices with better characteristics than the known Barker codes and their nested constructions. The results are significant, as this research influences the establishment and development of methods for isolation, detection and processing of useful information. The results of the work have a long aftermath because new original code synthesis methods need to be studied, modified, generalized and expanded for new application fields.Practical relevance: The practical application of the obtained results guarantees an increase in accuracy of location systems, and detection of a useful signal in noisy background. In particular, these results can be used in radar systems with high distance resolution, when detecting physical objects, including hidden ones.

2020 ◽  
Vol 8 (6) ◽  
pp. 5064-5068

Right now, point is to contrast single fix receiving patch and 1x2 exhibit and 1 x4 radio patch on FR4. The emphasis will be on upgrading the elements of fix reception apparatus additionally kept up a high increase in the ISM band (2.3 GHz to 2.6 GHz) at focus recurrence 2.45 GHz. Various parameters of reception apparatus like VSWR, return loss, increase gain and radiation design are reproduced utilizing Ansoft HFSS programming v13. Microstrip patch radio wire in remote correspondence is picking up significance as a most impressive mechanical pattern. Its enormous potential guarantees huge change in close to term eventual fate of remote application fields. The current innovative pattern has concentrated on microstrip patch radio wire. Single microstrip patch reception apparatus has a few favorable circumstances (ease, lightweight, conformal and low profile), however, it has little detriments too-like low addition, low productivity, low directivity, and thin data transfer capacity. These weaknesses can be overwhelmed by the execution of many fix reception apparatuses in a cluster design. Here term exhibit represents geometrical and electrical courses of action of fix components. As we increment the number of patch components to frame a cluster, improvement in execution is watched. Right now, for 1x1, 1x2, 1x4 clusters have been investigated and thought about. It has been inferred that the 1x4 patch cluster shows a preferable outcome over a single patch.


Author(s):  
G. V. Kulikov ◽  
Trung Tien Do ◽  
E. V. Samokhina

Objectives. The widespread use of radio data transmission systems using signals with multiposition phase shift keying (MPSK) is due to their high noise immunity and the simplicity of constructing the transmitting and receiving parts of the equipment. The conducted studies have shown that the presence of non-fluctuation interference, in particular, harmonic interference, in the radio channel significantly reduces the noise immunity of receiving discrete information. The energy loss in this case, depending on the interference intensity, can range from fractions of dB to 10 db or more. Therefore, interference suppression is an important task for such radio systems. The aim of the work is to synthesize and analyze an algorithm for optimal nonlinear filtering of MPSK signals against a background of harmonic interference with a random initial phase.Methods. The provisions of the theory of optimal nonlinear signal filtering and methods of statistical radio engineering are used.Results. The synthesis and analysis of the algorithm of optimal nonlinear filtering of MPSK signals against the background of harmonic interference with a random initial phase are carried out. The synthesized receiver contains a discrete symbol evaluation unit, two phase-locked frequency circuits of reference generators that form evaluation copies of the signal and interference, and cross-links between them. Analytical expressions are obtained that allow calculating the dependences of the bit error probability on the signal-to-noise ratio and the interference intensity µ. It is established that uncompensated fluctuations of the initial phase of the useful signal have a greater effect on the receiver noise immunity than similar fluctuations of the phase of harmonic interference, especially with low positional signals.Conclusions. Comparison of the obtained results with the results obtained in the case when there are no harmonic interference compensation circuits shows that the use of the obtained phase filtering algorithms allows for almost complete suppression of harmonic interference. Thus, if µ = 0.5 and the probability of error is 10−2, the energy gain at M = 2 is about 2.5 dB, at M = 4 – about 6 dB, at M = 8 and M = 16 – at least 10 dB.


2020 ◽  
Vol 49 (5) ◽  
pp. 58-63
Author(s):  
A. D. Sukharev ◽  
D. B. Piskunov

In the course of research activities in the field of new technologies of information interaction of on-board equipment of objects of rocket-space and aviation equipment, as well as study of protection of information against leakage through technical channels, there was a hypothesis, about stealth of radio channel formed by means of new and promising developing technologies. The article discusses the use of radio wave interference control technologies (on adaptive formation of the sum of the signal phases) for beam formation. The features of the MU-MIMO and OFDMA technologies, which allows several simultaneous outgoing streams (downlink, uplink), providing simultaneous servicing of several devices at once, which increases the performance of the network as a whole, are considered. The implementation of the secrecy of the operation of the radio channel based on the considered technology for potential unauthorized detection of the operation of the radio channel and access to the transmitted information outside the beam pointing points is considered. Based on the description of the technology and on-site experiments, conclusions are drawn and recommendations are formulated on the methodology for detecting unauthorized data transfer implemented on the basis of the technology considered.


Connectivity ◽  
2020 ◽  
Vol 145 (3) ◽  
Author(s):  
K. O. Domracheva ◽  
◽  
A. V. Voloshenko ◽  
O. L. Zolkyn ◽  
R. M. Kyrychenko

The actual issue of increasing the data transfer rate in telecommunication systems with MIMO is considered. It is proposed to use an increase in the signal-to-noise ratio due to the processing and addition of signals from parallel antenna channels to increase the throughput of the system by applying quadrature amplitude manipulation. System simulation for MIMO 4x4. The error probability for QAM is calculated. A method is proposed that allows to increase by 4 times the information transfer rate while maintaining the signal duration and, accordingly, the bandwidth of the radio channel. According to the proposed methodology, telecommunication systems can be created with large numbers of multiposition amplitude-manipulated signals, as well as in combination with multiposition phase-shifted signals. It is shown that an increase in the signal-to-noise ratio when processing signals from parallel antenna channels cannot increase the system capacity, but only lead to a decrease in the signal reception error.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
G.V. Kulikov ◽  
◽  
Khang Dang ◽  

The development of television technologies and the need to transmit high-quality video information requires that modern digital television and broadcasting systems can transmit large amounts of information. The use of signals with multi-position amplitude and phase-shift keying 16-APSK and 32-APSK in DVB-S2 generation satellite television systems made it possible to transmit 30% more data in the same frequency bands compared to the previous DVB-S standard. The latest DVB-S2X digital satellite TV standard is an extension of the DVB-S2 standard and supports modulations of 64,128,256-APSK. It is known that increasing the positionality of signals reduces the noise immunity of their reception and the system as a whole. In addition, the presence of non-fluctuation interference in the radio channel that falls into the frequency band of the useful signal has a strong influence on noise immunity. The article uses statistical radio engineering methods to calculate the probability of a bit error when receiving M-APSK signals against the background of phase-shift keying interference at different parameters of the latter. It is shown that of phase-shift keying interference of even low intensity (µ < 0.3) falling into the main lobe of the signal spectrum significantly reduces the noise immunity of receiving 16-APSK and 32-APSK signals. High-intensity interference (µ ≥ 0.5) practically destroys reception. The influence of phase-shift keying interference decreases with an increase in its detuning relative to the carrier frequency of the useful signal and an increase in the relative transmission rate of the interference. A comparison of the reception quality when using M-PSK, M-QAM and M-APSK signals is carried out and it is shown that the noise immunity of receiving M-QAM and M-APSK against the background of phase-shift keying interference is approximately the same. M-PSK signals are significantly inferior to them in terms of reception noise immunity.


Author(s):  
М.Б. ПРОЦЕНКО ◽  
В.В. ГРОМОЗДИН ◽  
К.В. ИЕВЛЕВ ◽  
М.С. КОЗУБ

В работе рассмотрены такие характеристики судового ОВЧ радиоканала, как напряженность поля полезного сигнала и ЭДС полезного сигнала на входе радиоприемного устройства (РПУ),которые являются функциями от отношения сигнал/шум на выходе (входе)РПУ. Введено понятие фактической чувствительности РПУ. Определены количественные значения анализируемых характеристик применительно к типовому судовому радиооборудованию и шумовой обстановке вблизи судовой антенны. The article considers such characteristics of the shipboard VHF radio channel as the electromagnetic field strength of the useful signal and the EMF of the useful signal at the input of the receiver, which are functions of the signal-to-noise ratio at the output (input) of the receiver. The concept of the actual sensitivity of the receiver is introduced. The quantitative values of the analyzed characteristics are determined in relation to the typical ship radio equipment and the noise environment near the ship antenna.


2019 ◽  
Vol 5 (4) ◽  
pp. 37-48
Author(s):  
A. Lomakin ◽  
D. Pantenkov ◽  
V. Sokolov

The article is devoted to the issues of stealth satellite radio channels with unmanned aerial vehicles (UAV) and it is consists of two parts. In the first part of this article the following questions are considered: the general statement of a system development problem of satellite model communication providing its stealth functioning by means of radio monitoring is carried out; the mathimatical apparatus for the assessing the effectiveness of ensuring spatial selectivity in the organization of satellite communication lines at hidden objects of their functioning is presented; the functioning model of the satellite communication system wich use the signal processing methods to ensure the secrecy of its functioning by means of radio monitoring is developed; in the conclusion, proposals and recommendations are formulated to ensure the secrecy of the satellite radio channel with unmanned aerial vehicles. Since the eventual opponent a priori lacks complete reliable information about the radio monitoring signal, the second part of the article considers the methods of quasi-optimal signal processing based on auto-and intercorrelation processing, which allows to obtain a significant energy gain and detect a useful signal even at a very low level of its power at the input. The use of autocorrelation signal processing devices significantly improves the efficiency of radio monitoring (RM), which is especially important in the case of negative ratios of useful signal power and noise at the input of autocorrelation signal processing devices. The main results of the second part of the article include: a mathematical functioning model of the opponent's RM means in the conditions of taking measures to ensure the information transfer secrecy, the parameters calculations results of the satellite system provided that it is hidden from the RM means.


2021 ◽  
Vol 11 (11) ◽  
pp. 4956
Author(s):  
Dawon Kim ◽  
Yosoon Choi

The aim of this study is to review academic papers on the applications of smart glasses. Among 82 surveyed papers, 57 were selected through filtering. The papers were published from January 2014 to October 2020. Four research questions were set up using the systematic review method, and conclusions were drawn focusing on the research trends by year and application fields; product and operating system; sensors depending on the application purpose; and data visualization, processing, and transfer methods. It was found that the most popular commercial smart glass products are Android-based Google products. In addition, smart glasses are most often used in the healthcare field, particularly for clinical and surgical assistance or for assisting mentally or physically disabled persons. For visual data transfer, 90% of the studies conducted used a camera sensor. Smart glasses have mainly been used to visualize data based on augmented reality, in contrast with the use of mixed reality. The results of this review indicate that research related to smart glasses is steadily increasing, and technological research into the development of smart glasses is being actively conducted.


Author(s):  
Henry Engledow

Migrating from one database to another is always accompanied by challenges. Recently Meise Botanic Garden has migrated its Living Collections data from LivCol, a bespoke database, to BG-BASE, a commercial product. Differences in database structure, degree of atomisation and field definition increase the complexity of such a transfer of data. The greater the number of fields used in the original data source, the greater the number of problems there are to resolve. Living collections are often centered around the 'accession information' of the living material, but the way one does this and the philosophy behind this may differ. The different approach to accessioning material in LivCol and BG-BASE affected the structure of the data model in each program. The LivCol approach was not as strictly defined as the BG-BASE approach e.g. new generations derived from existing accessions in LivCol retained the same accession number despite being not genetically identical (of seed origin), whereas in BG-BASE a new accession number would be generated with reference to the parent accession. In the data transfer LivCol accession number where grouped by accession number and garden location, and the inter-generation information combined in a single record in BG-BASE (this is not ideally in accordance with the BG-BASE concept, the alternative was to create 'artificial' new accession numbers but this would have complicated matters more both from a data and management point of view). The use of standards would greatly improve data transfer, and indeed many standards have been adopted by both the above mentioned databases. However, it soon became evident that there are multiple standards for a single topic e.g. for information concerning conservation status: NatureServe Global Conservation Status Ranks; Fish &amp; Wildlife conservation category; International Union for Conservation of Nature (IUCN) - old and new codes (plus version); Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES); etc. Also, some values used are region specific and do not translate well to ‘global’ standards e.g. in Belgium there are three principal regions controlling conservation status (Brussels, Flanders, Wallonia) and they differ in their approach and definitions, all these need to be taken into account as there are legal implications - this was done by finding close matches in IUCN (New) codes and combining them with 'non-standard' World Geographical Scheme for Recording Plant Distributions (WGSRPD). The latter TDWG standard is out of date and in many circumstances not sufficiently atomised to be of practical use. There were also certain fields that would benefit from having standards, but are at present absent e.g. invasiveness - BG-BASE uses Cronk and Fuller (1995) whereas LivCol uses AlterIAS (http://www.alterias.be/), Belgian Forum on Invasive Species (http://ias.biodiversity.be) and Lambinon et al. (1992). The above problems will be discussed and their impact on mapping the data. Decisions had to be made with respect to ‘best fit’ solutions. The latter lead to the loss of information or a slight variation in its interpretation, examples will be given to highlight these aspects. As the structures of the databases differed, sometimes assumptions had to be made, this too will be illustrated. These changes were reasonable, but represent an interpretation of the original data and therefore not strictly the same. Databases are crucial to the management of Living Collections and the research done on them. This talk will look at the lessons learned during the data transfer and the problems associated with mapping (decisions, assumptions and standards). Databases are 'living' entities that need to grow, adapt, be maintained and regularly updated to new developments in technology. Databases are not seen as new or innovative by funding bodies and are often left to struggle along in suboptimal conditions. If we want data quality to improve and increase interoperability between systems, maybe we should start at the point where data is entered.


2021 ◽  
Vol 17 ◽  
Author(s):  
Wanzhe Tong ◽  
Qinhong Yin ◽  
Dong Fang ◽  
Taofang Zeng ◽  
Jianhong Yi

: Silicon quantum dots (Si QDs) with the unique properties in light, electricity, magnetism and heat possess the advantages of non-toxic, environmental protection and abundant reserves. They are widely used in various fields and have great potential for development. Till now, numerous researchers have reported the research progress of Si QDs, or elaborated the behavior mechanism. However, there are few summarization and comparison on the properties of quantum dot properties in different fields and different preparation methods. Besides, the parameters of Si QDs vary greatly in different application fields, which is worthy of comparison and summary. During the current work, we review the research progress and synthesis methods in recent years. The main influencing factors of Si QDs of different preparation methods (physical and chemical) and different application properties (fluorescence detection, solar cell, photocatalyst and composite) are compared and discussed in detail. Therefore, this paper aims to find promising preparation methods for different application fields, and to provide a clear direction for researchers to study Si QDs in different directions.


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