scholarly journals ABOUT RELATIONSHIP BETWEEN THE SIGNAL POWER, NUMBER OF M-QAM POSITIONS AND NOISE IMMUNITY IN BROADBAND WIRELESS ACCESS SYSTEMS

2020 ◽  
Vol 6 (3) ◽  
pp. 24-28
Author(s):  
Isa Mammedov ◽  
◽  
Ilham Afandiyev ◽  
Keyword(s):  
Measurement Error ◽  
Random Process ◽  
Error Probability ◽  
Noise Immunity ◽  
Energy Parameter ◽  
Base Station ◽  
Inertial System ◽  
Pilot Signal ◽  
Modulation Type ◽  
Forward Channel

Is studied the effect of measurement error on the accuracy of selecting the modulation type in the transmitter of the base station. The article discusses changes in the statistical characteristics of the measured signal as it passes through the stage of the feedback loop of the system of the LMDS type. Probabilistic characteristics of pilot-signal are determined at the output of this loop. The aim of the work was to find a compromise between the type of modulation and the power of the BS transmitter to maintain the transmission faithfulness within the given limits in the forward channel of an interactive wireless broadband radio access system of the LMDS. In this system a transition is made from one type of modulation to another in order to maintain the noise immunity of the system within the admissible limits. An adaptive controlling method of modulation type makes it possible to obtain an energy gain in the forward channel of the system. It is useful to determine the type of modulation by measuring the current value of the signal-to-interference ratio at the base station (BS) receiver. For this purpose a pilot signal is transmitted on the reverse channel of the system. This signal, passing through the turbulent medium, undergoes attenuation, and therefore at the input of the BS receiver we have a random process. Moreover, the distribution law of this process can be different and is determined by the communication channel model. The problem consisted in determining the necessary probabilistic characteristics of the output process by using the system parameters and probabilistic characteristics of the input random process. For this purpose the cumulants of the input random process and the random process at the output of the linear inertial system are determined. An expression for the probability density of the random process at the output of a linear inertial system is obtained. The graphics of the error probability on the energy parameter at 16-QAM and 64-QAM type of modulation are constructed. The influence of the measurement error on the accuracy of the choice of the modulation type in the transmitter of the BS is studied. The limits of the change in the energy parameter are defined graphically, under which the modulation type changes to ensure a given error probability. It is determined, that the system is more critical to the measurement error at high admissible error probability, i.e. at high error probabilities, small errors in the measurement of the signal-to-noise ratio make it necessary to transition to a more noise-immune modulation mode.

scholarly journals Physical-Layer Security Improvement with Reconfigurable Intelligent Surfaces for 6G Wireless Communication Systems

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1439
Author(s):  
Janghyuk Youn ◽  
Woong Son ◽  
Bang Chul Jung
Keyword(s):  
Wireless Communication ◽  
Physical Layer Security ◽  
Communication Systems ◽  
Low Cost ◽  
Physical Layer ◽  
Base Station ◽  
Wireless Communication Systems ◽  
Secrecy Rate ◽  
Pilot Signal ◽  
Time Division

Recently, reconfigurable intelligent surfaces (RISs) have received much interest from both academia and industry due to their flexibility and cost-effectiveness in adjusting the phase and amplitude of wireless signals with low-cost passive reflecting elements. In particular, many RIS-aided techniques have been proposed to improve both data rate and energy efficiency for 6G wireless communication systems. In this paper, we propose a novel RIS-based channel randomization (RCR) technique for improving physical-layer security (PLS) for a time-division duplex (TDD) downlink cellular wire-tap network which consists of a single base station (BS) with multiple antennas, multiple legitimate pieces of user equipment (UE), multiple eavesdroppers (EVEs), and multiple RISs. We assume that only a line-of-sight (LOS) channel exists among the BS, the RISs, and the UE due to propagation characteristics of tera-hertz (THz) spectrum bands that may be used in 6G wireless communication systems. In the proposed technique, each RIS first pseudo-randomly generates multiple reflection matrices and utilizes them for both pilot signal duration (PSD) in uplink and data transmission duration (DTD) in downlink. Then, the BS estimates wireless channels of UE with reflection matrices of all RISs and selects the UE that has the best secrecy rate for each reflection matrix generated. It is shown herein that the proposed technique outperforms the conventional techniques in terms of achievable secrecy rates.

THE ANALYTICAL MODEL OF NOISE IMMUNITY CALCULATION OF COMMUNICATION SYSTEMS WITH MULTI-POSITION TYPES OF MODULATION AND CONVOLUTIONAL CODING

2020 ◽  
Author(s):  
Э.Б. ЛИПКОВИЧ ◽  
А.А. СЕРЧЕНЯ
Keyword(s):  
Computer Simulations ◽  
Communication Systems ◽  
Error Probability ◽  
Noise Immunity ◽  
Convolutional Code ◽  
Analytical Models ◽  
Signal To Noise ◽  
Probability Of Error ◽  
Information Efficiency ◽  
Convolutional Coding

Получены математические модели расчета отношений сигнал/шум и несущая/шум, требуемые для обеспечения заданной вероятности ошибки на выходе декодера с «мягким» решением, без необходимости вычисления коэффициентов спектра сверточного кода и выполнения процедур компьютерного моделирования характеристик помехоустойчивости. Приведены расчетные выражения для определения исправляющей способности декодера, энергетического выигрыша от кодирования и информационной эффективности систем связи в зависимости от параметров многопозиционных видов модуляции, сверточного кодирования и вероятности ошибки в информационном бите. По полученным аналитическим моделям построены зависимости и дана оценка результатов исследований. Mathematical models are obtained for calculating signal-to-noise and carrier-to-noise ratios required to provide a given error probability at the decoder output with a “soft” solution and without calculating the convolutional code spectrum coefficients and performing computer simulations of noise immunity characteristics. Calculation expressions are given to determine the correcting ability of the decoder, the energy gain from coding, and the information efficiency of communication systems depending on the parameters of multi-position types of modulation, convolutional coding, and the probability of error in the information bit. Dependencies are constructed according to the obtained analytical models and the research results are evaluated.

scholarly journals Joint use of frequency-time division and antinoise coding in radio communication systems with FHSS

2021 ◽  
Vol 9 (4) ◽  
pp. 77-84
Author(s):  
A. A. Paramonov ◽  
Van Zung Hoang
Keyword(s):  
Data Transmission ◽  
Communication Systems ◽  
Error Probability ◽  
Noise Immunity ◽  
Signal To Noise Ratio ◽  
Frequency Division ◽  
Radio Communication ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Time Division

In the context of continuous improvement of radio prospecting and active radio jamming technics along with introduction of automated active countermeasures systems (ACS), the frequency-hopping spread spectrum (FHSS) radio communication systems (RCS) are widely used in order to improve reliability and noise immunity of data transmission. The noise immunity of the RCS affected by unintentional or deliberate interference can be significantly perfected by the combined use of frequency-time division and antinoise coding. This paper explores the case when the interference created by an ACS system with a limited transmitter power covers a part of the RCS frequency range. The receiver gets input mix of the wanted signal, the receiver noise, and probably a deliberate interference also considered as a noise. The article analyzes the noise immunity of signals reception with FHSS in the low-speed radio systems with joint use of frequency-time division of information subsymbols and noise combating codes when the deliberate interference destructively impacts a part of the RCS working band. Dependence of the bit error probability on the signal-to-noise ratio is calculated for the joint use of frequency division of information subsymbols and noise combating codes. It is shown that due to effective use of the frequency-energy resource of a radio line, considering the use of correction codes, a quite high noise immunity of RCS under the influence of deliberate interference can be assured. The indicated dependences of the error probability on the signal-to-noise ratio confirm that the reliability of data transmission can be significantly increased by the proper combination of signal spectrum spreading, applying of correction codes, and frequency division of subsymbols followed by their weight processing.

Пространственно-временное кодирование в системах MISO

2020 ◽  
Author(s):  
M.A. Bykhovskiy
Keyword(s):  
Noise Immunity ◽  
Signal Transmission ◽  
Base Station ◽  
Space Time ◽  
Radio Waves ◽  
Space Time Codes ◽  
The One ◽  
Error Probabilities

The analysis of noise immunity of MISO systems withKantennas at the base station (BS) and Space-Time Codes (STC) is performed. This system, as compared to STC systems, selects just one of K antennas for signal transmission the one whose radiation during radio waves broadcasting along the route BSuser station has the least attenuation. Formulas allowing to calculate error probabilities at the reception of multiposition signals with QAM and the various number of transmitting antennas at BSs both in STC systems and in the new MISO system are obtained. Выполнен анализ помехоустойчивости систем MISO с K антеннами на базовой станции (БС) и пространственно-временными кодами (ПВК). Дано описание и выполнен анализ помехоустойчивости новой, более простой в реализации, системы MISO, также имеющей K антенн на БС. В ней, в отличие от систем с ПВК, для передачи сигналов выбирается лишь одна из K антенн, излучение которой при распространении радиоволн на трассе от БС к абонентской станции (АС) ослабляется в наименьшей степени. Получены формулы, позволяющие вычислить вероятности ошибки при приеме многопозиционных сигналов с квадратурно-амплитудной модуляцией при разном числе передающих антенн на БС как в системах с ПВК, так и в новой системе MISO. Показано, что при одном и том же количестве передающих антенн на БС новая система MISO по сравнению с системой с ПВК обеспечивает энергетический выигрыш, составляющий 2 дБ. С увеличением количества передающих антенн K этот выигрыш увеличивается.

scholarly journals Comparative analysis of noise immunity of reception of nonlinear complex discrete signals with standard signals AFM-16 BPSK

Radiotekhnika ◽  
2020 ◽  
pp. 133-140
Author(s):  
S.G. Rassomakhin ◽  
A.A. Zamula ◽  
I.D. Gorbenko ◽  
Ho Tri Luc
Keyword(s):  
Comparative Analysis ◽  
Error Probability ◽  
Noise Immunity ◽  
Signal To Noise Ratio ◽  
Statistical Simulation ◽  
Gaussian Channel ◽  
Signal To Noise ◽  
Discrete Signals ◽  
Noise Ratio ◽  
Correlation Properties

The article shows that the solution to the problem of increasing the noise immunity (noise immunity and secrecy of functioning) of the ICS can be achieved using systems of nonlinear signals with improved ensemble, structural and correlation properties. Two classes of nonlinear complex discrete signals are considered: characteristic discrete signals (CDS) and cryptographic signals (CS). Methods for the synthesis of these signals are presented. The paper gives a statistical simulation model for studying the noise immunity of various classes of signals in the Gaussian channel. Using this model, estimates of the dependence of the error probability on the signal-to-noise ratio were obtained for various classes of signals, namely: CDS, KS and standard BPSK AFM-16 signals. It is shown that for the signal-to-noise ratio – 10 the error probability for the CDR is 4.6875e-06, for the CS is 3.515625e-06, and for the AFM-16 is 0.002025. Thus, the use of nonlinear complex discrete signals, in particular, CDS and KS, can significantly increase the noise immunity of signal reception in modern ICS. At the same time, taking into account the improved ensemble and structural properties of these nonlinear signals, it is possible to improve significantly the indicators of crypto- and imitation security of the systems functioning.

scholarly journals DIRECT GEOREFERENCING ON SMALL UNMANNED AERIAL PLATFORMS FOR IMPROVED RELIABILITY AND ACCURACY OF MAPPING WITHOUT THE NEED FOR GROUND CONTROL POINTS

2015 ◽  
Vol XL-1/W4 ◽  
pp. 397-402 ◽  
Author(s):  
O. Mian ◽  
J. Lutes ◽  
G. Lipa ◽  
J. J. Hutton ◽  
E. Gavelle ◽  
...  
Keyword(s):  
Base Station ◽  
Test Area ◽  
Rural Setting ◽  
Inertial System ◽  
Ground Control ◽  
Control Points ◽  
Post Processing ◽  
Ground Sample ◽  
Ground Control Points ◽  
Test Flight

This paper presents results from a Direct Mapping Solution (DMS) comprised of an Applanix APX-15 UAV GNSS-Inertial system integrated with a Sony a7R camera to produce highly accurate ortho-rectified imagery without Ground Control Points on a Microdrones md4-1000 platform. A 55 millimeter Nikkor f/1.8 lens was mounted on the Sony a7R and the camera was then focused and calibrated terrestrially using the Applanix camera calibration facility, and then integrated with the APX-15 UAV GNSS-Inertial system using a custom mount specifically designed for UAV applications. <br><br> In July 2015, Applanix and Avyon carried out a test flight of this system. The goal of the test flight was to assess the performance of DMS APX-15 UAV direct georeferencing system on the md4-1000. The area mapped during the test was a 250 x 300 meter block in a rural setting in Ontario, Canada. Several ground control points are distributed within the test area. The test included 8 North-South lines and 1 cross strip flown at 80 meters AGL, resulting in a ~1 centimeter Ground Sample Distance (GSD). <br><br> Map products were generated from the test flight using Direct Georeferencing, and then compared for accuracy against the known positions of ground control points in the test area. The GNSS-Inertial data collected by the APX-15 UAV was post-processed in Single Base mode, using a base station located in the project area via POSPac UAV. The base-station’s position was precisely determined by processing a 12-hour session using the CSRS-PPP Post Processing service. The ground control points were surveyed in using differential GNSS post-processing techniques with respect to the base-station.

A Bio-Inspired Approach for the Next Generation of Cellular Systems

2009 ◽  
pp. 3204-3210
Author(s):  
Mostafa El-Said
Keyword(s):  
Access Network ◽  
Base Station ◽  
Cellular Systems ◽  
Vertical Handoff ◽  
Pilot Signal ◽  
Radio Access ◽  
4G Wireless ◽  
Network Status ◽  
High Level ◽  
3G Systems

In the current 3G systems and the upcoming 4G wireless systems, missing neighbor pilot refers to the condition of receiving a high-level pilot signal from a Base Station (BS) that is not listed in the mobile receiver’s neighbor list (LCC International, 2004; Agilent Technologies, 2005). This pilot signal interferes with the existing ongoing call, causing the call to be possibly dropped and increasing the handoff call dropping probability. Figure 1 describes the missing pilot scenario where BS1 provides the highest pilot signal compared to BS1 and BS2’s signals. Unfortunately, this pilot is not listed in the mobile user’s active list. The horizontal and vertical handoff algorithms are based on continuous measurements made by the user equipment (UE) on the Primary Scrambling Code of the Common Pilot Channel (CPICH). In 3G systems, UE attempts to measure the quality of all received CPICH pilots using the Ec/Io and picks a dominant one from a cellular system (Chiung & Wu, 2001; El-Said, Kumar, & Elmaghraby, 2003). The UE interacts with any of the available radio access networks based on its memorization to the neighboring BSs. As the UE moves throughout the network, the serving BS must constantly update it with neighbor lists, which tell the UE which CPICH pilots it should be measuring for handoff purposes. In 4G systems, CPICH pilots would be generated from any wireless system including the 3G systems (Bhashyam, Sayeed, & Aazhang, 2000). Due to the complex heterogeneity of the 4G radio access network environment, the UE is expected to suffer from various carrier interoperability problems. Among these problems, the missing neighbor pilot is considered to be the most dangerous one that faces the 4G industry. The wireless industry responded to this problem by using an inefficient traditional solution relying on using antenna downtilt such as given in Figure 2. This solution requires shifting the antenna’s radiation pattern using a mechanical adjustment, which is very expensive for the cellular carrier. In addition, this solution is permanent and is not adaptive to the cellular network status (Agilent Technologies, 2005; Metawave, 2005).

Detection and Measurement of the Unknown Moment and Magnitude of the Gaussian Random Process Energy Parameter Abrupt Change

2019 ◽  
Vol 12 (5) ◽  
pp. 264
Author(s):  
Oleg Vyacheslavovich Chernoyarov ◽  
Branislav Dobrucky ◽  
Alexandra Valerievna Salnikova ◽  
Alexander Andreevich Makarov
Keyword(s):  
Random Process ◽  
Abrupt Change ◽  
Energy Parameter ◽  
Gaussian Random Process ◽  
Process Energy

Multi-position signal coherent reception error probability in a channel with generalized gamma or K fading and white noise

2019 ◽  
pp. 76-88 ◽  
Author(s):  
N. V. Savischenko ◽  
E. V. Lebeda
Keyword(s):  
Gaussian Noise ◽  
Error Probability ◽  
Hypergeometric Functions ◽  
Communication Channel ◽  
Noise Immunity ◽  
Special Function ◽  
Additive White Gaussian Noise ◽  
Algebraic Function ◽  
White Gaussian Noise ◽  
Position Signal

Introduction:One of the main problems in communication theory is giving definitions to such characteristics of an information transmission system as noise immunity (error probability) and transfer rate. Their knowledge allows you to determine the transmitted information quality and quantity, respectively. The calculation of the error probability for a communications channel (for example, with fading) allows you to estimate the loss or gain in noise immunity with modems of various signal designs.Purpose:Developing a technique for calculating the probability of a bit error with coherent reception of signals in a communication channel with additive white Gaussian noise and general (non-selective in terms of frequency) fading described by gamma distribution orKdistribution (called gamma fading andKfading respectively).Results:The obtained relations allow you to calculate the reception noise immunity in arbitrary twodimensional signaling designs for a communication channel with gamma orKfading and additive white Gaussian noise. Examples are given of bit error probability calculation for phase modulation and quadrature-amplitude modulation signals. The calculation of error probability in a channel with fading for two different distribution laws was reduced to a new special function which is an integral of the product of Tricomi function and an algebraic function. This allowed us to develop a universal mathematical approach valid for both variants of fading. To calculate the new special function introduced in the article and its representation through the known functions, we used both classical hypergeometric functions and a generalized hypergeometric functions of two variables which is Kampé de Fériet function.Practical relevance:When using multi-position signal structures in new telecommunication standards, this technique allows you to obtain an estimate of their potential noise immunity, objectively comparing signal constructions and correctly choosing the best options for new modem developer.

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