The document summarizes research on comparing the performance of different adaptive beamforming algorithms for smart antenna systems. Simulation results showed that training sequence algorithms like recursive least squares (RLS) and least mean squares (LMS) formed the best main lobes towards the desired user but had limitations in interference rejection. The constant modulus algorithm (CMA) provided better interference rejection but a higher bit error rate for a single antenna element. RLS was found to have the fastest convergence rate, making it the best choice. Increasing the step size for LMS affected its performance. Overall, RLS was found to perform best across parameters like beampattern, amplitude response, error, and bit error rate.
In next five years 5G is the most popular and anticipated mobile technology and beam forming is one of the important aspect of 5G networks Beam forming is a technique used by sensor arrays for a directional signal transmission or reception and is very important for number of applications like Radar, biomedicine, radio communications, SONAR The paper introduces beam forming technique sand its importance in the modern cellular society Irfan Nissar Bhat | Er. Harish Dogra "Beamforming for 5G Networks" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-6 , October 2018, URL: http://www.ijtsrd.com/papers/ijtsrd18405.pdf
In next five years 5G is the most popular and anticipated mobile technology and beam forming is one of the important aspect of 5G networks Beam forming is a technique used by sensor arrays for a directional signal transmission or reception and is very important for number of applications like Radar, biomedicine, radio communications, SONAR The paper introduces beam forming technique sand its importance in the modern cellular society Irfan Nissar Bhat | Er. Harish Dogra "Beamforming for 5G Networks" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-6 , October 2018, URL: http://www.ijtsrd.com/papers/ijtsrd18405.pdf
Survey paper on adaptive beamforming lms,nlms and rls algorithms for smart an...eSAT Journals
Abstract
Smart antenna system is used to maximize the output power of signal in desired direction and minimize the power in unwanted direction. Smart antenna system consists of multiple numbers of elements. Basic concept in smart antenna technology is beam forming, it is mainly used to improve signal to noise ratio. Beam forming signal processing technique used in sensor arrays for directional signal transmission and reception. And it possible by combining the elements in phased array in such a way that signals at particular angles experiences constructive interference and others are destructive interferences. In smart antenna system we are using various algorithms to calculate the weights of smart antenna arrays to increase the output in desired direction and reduce the power in unwanted direction We are using different types of arrays i.e. linear array, circular array, planar array . Different algorithms are used to adjust the weights of the smart antenna system Basically Weights are nothing but Amplitude and phase of the signal. Adaptive algorithms update the weights of the array elements. LMS algorithm provides less convergence speed, and that is depends on the step size. LMS algorithm is widely used in adaptive filter due to its relative low computational complexity, good stability and relatively good robustness against the implementation errors. To improve the convergence rate NLMS algorithm is used. LMS algorithm having constant step size but in NLMS algorithm step size is depends on data at each iteration. Whereas RLS algorithm having minimum bit error rate but it required more computations than the LSM algorithm.
Keywords: Beamforming, smart antenna, complex weight, array geometry, Array factor
SIMULATIONS OF ADAPTIVE ALGORITHMS FOR SPATIAL BEAMFORMINGijiert bestjournal
The main aim of this paper is to simulate different types of Adaptive Algorithms for Spatial Beam forming,which is achieved by combinin g elements of a phased array in such a way that signals at particular angles experi ence constructive interference while others experience destructive interference. Here,s imulations are done on different types of Adaptive Algorithms in MATLAB and Simulink to de termine the desired signal from clutter/noise by updating its weight value for bett er execution speed and computational complexity and the characteristics of individual al gorithms are compared and their area of applications. Adaptive filter is a filter that s elf-adjusts its transfer function according to an optimization algorithm driven by an error sig nal. The adaptive beamforming algorithms are used to update the weight vectors pe riodically to track the signal source in time varying environment by adaptively modifying the system�s antenna pattern so that nulls are generated in the directions of the i nterference sources.
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
A NEW MODIFIED SYSTEM FOR EQUAL POWER DIVISION WITH LCC FOR WIRELESS APPLCATIONSijistjournal
In this paper, a new modified system for equal power division is implemented with the help of rectangular micro strip patch antenna, Gysel power divider and leakage cancellation circuit. Today’s world power division plays an important role in wireless application areas such as base stations, antenna arrays, handheld devices etc., Here micro strip patch antenna is implemented with FR4 as a substrate material due to its benefits such as low loss and low fabrication cost while the ground material is aluminium due to its conductivity. For a good system, the return loss should be highly desirable and insertion loss should be low. Our proposed system is designed with a combination of micro strip patch antenna, leakage cancellation circuit and Gysel power divider produces equal power division with low loss such as insertion loss is measured as -39.291dB, return loss as -16.11dB and leakage cancellation as 6dB which was designed and simulated in Agilent Advanced Design System software (2009).
DETECTION OF POWER-LINES IN COMPLEX NATURAL SURROUNDINGScsandit
Power transmission line inspection using Unmanned Aerial Vehicles (UAV) is taking off as an
exciting solution due to advances in sensors and flight technology. Extracting power-lines from
aerial images, taken from the UAV, having complex natural surroundings is a critical task in the
above problem. In this paper we propose an approach for suppressing natural surrounding that
leads to power line detection. The results of applying our method on real-life video frames taken
from a UAV demonstrate that our approach is very effective. We believe that our approach can
be easily used for line detection in any other real outdoor video as well.
Dynamic Beamforming Optimization for Anti-Jamming and Hardware Fault RecoveryJonathan Becker
In recent years there has been a rapid increase in the number of wireless devices for both commercial and defense applications. Such unprecedented demand has increased device cost and complexity and also added a strain on the spectrum utilization of wireless communication systems. This thesis addresses these issues, from an antenna system perspective, by developing new techniques to dynamically optimize adaptive beamforming arrays for improved anti-jamming and reliability.
Available frequency spectrum is a scarce resource, and therefore increased interference will occur as the wireless spectrum saturates. To mitigate unintentional interference, or intentional interference from a jamming source, antenna arrays are used to focus electromagnetic energy on a signal of interest while simultaneously minimizing radio frequency energy in directions of interfering signals. The reliability of such arrays, especially in commercial satellite and defense applications, can be addressed by hardware redundancy, but at the expense of increased volume, mass as well as component and design cost.
This thesis proposes the development of new models and optimization algorithms to dynamically adapt beamforming arrays to mitigate interference and increase hardware reliability. The contributions of this research are as follows. First, analytical models are developed and experimental results show that small antenna arrays can thwart interference using dynamically applied stochastic algorithms. This type of in-situ optimization, with an algorithm dynamically optimizing a beamformer to thwart interference sources with unknown positions, inside of a anechoic chamber has not been done before to our knowledge. Second, it is shown that these algorithms can recover from hardware failures and localized faults in the array. Experiments were performed with a proof-of-concept four-antenna array. This is the first hardware demonstration showing an antenna array with live hardware fault recovery that is adapted by stochastic algorithms in an anechoic chamber. We also compare multiple stochastic algorithms in performing both anti-jamming and hardware fault recovery. Third, we show that stochastic algorithms can be used to continuously track and mitigate interfering signals that continuously move in an additive white Gaussian noise wireless channel.
Narrowband Spectrum Sensing for Different Fading Channels for Cognitive Radio...IJMERJOURNAL
Abstract: Nowadays the demand of applications of wireless communication has increased rapidly which causes the scarcity of radio spectrum. To empower future wireless communication services, the radio spectrum management is a very important factor. Cognitiveradio is a promising technology which provides an innovative way to improve utilization efficiency of available electromagnetic spectrum by sensing spectrum and shares it without harmful interference to other users. Narrowband spectrum sensing is the technique where the bandwidth of active primary transmitter in the vicinity of cognitive radio is less than the coherence bandwidth of channel. Fading is one of the greatest impairment of narrowband spectrum sensing. It is deflection of the attenuation. It influences a signal over certain propagation media.A communication channel that experiences fading isknown as fading channel. The effects of fading can be reduced by several fading models. In this paper, performanceanalysis of several realistic fading models on narrowband channel using energy detection method is employed. Finally, performance comparison of various fading models is guaranteed through simulation.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Sidelobe rejection in a uniform linear array antenna using windowing techniqueseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Survey paper on adaptive beamforming lms,nlms and rls algorithms for smart an...eSAT Journals
Abstract
Smart antenna system is used to maximize the output power of signal in desired direction and minimize the power in unwanted direction. Smart antenna system consists of multiple numbers of elements. Basic concept in smart antenna technology is beam forming, it is mainly used to improve signal to noise ratio. Beam forming signal processing technique used in sensor arrays for directional signal transmission and reception. And it possible by combining the elements in phased array in such a way that signals at particular angles experiences constructive interference and others are destructive interferences. In smart antenna system we are using various algorithms to calculate the weights of smart antenna arrays to increase the output in desired direction and reduce the power in unwanted direction We are using different types of arrays i.e. linear array, circular array, planar array . Different algorithms are used to adjust the weights of the smart antenna system Basically Weights are nothing but Amplitude and phase of the signal. Adaptive algorithms update the weights of the array elements. LMS algorithm provides less convergence speed, and that is depends on the step size. LMS algorithm is widely used in adaptive filter due to its relative low computational complexity, good stability and relatively good robustness against the implementation errors. To improve the convergence rate NLMS algorithm is used. LMS algorithm having constant step size but in NLMS algorithm step size is depends on data at each iteration. Whereas RLS algorithm having minimum bit error rate but it required more computations than the LSM algorithm.
Keywords: Beamforming, smart antenna, complex weight, array geometry, Array factor
SIMULATIONS OF ADAPTIVE ALGORITHMS FOR SPATIAL BEAMFORMINGijiert bestjournal
The main aim of this paper is to simulate different types of Adaptive Algorithms for Spatial Beam forming,which is achieved by combinin g elements of a phased array in such a way that signals at particular angles experi ence constructive interference while others experience destructive interference. Here,s imulations are done on different types of Adaptive Algorithms in MATLAB and Simulink to de termine the desired signal from clutter/noise by updating its weight value for bett er execution speed and computational complexity and the characteristics of individual al gorithms are compared and their area of applications. Adaptive filter is a filter that s elf-adjusts its transfer function according to an optimization algorithm driven by an error sig nal. The adaptive beamforming algorithms are used to update the weight vectors pe riodically to track the signal source in time varying environment by adaptively modifying the system�s antenna pattern so that nulls are generated in the directions of the i nterference sources.
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
A NEW MODIFIED SYSTEM FOR EQUAL POWER DIVISION WITH LCC FOR WIRELESS APPLCATIONSijistjournal
In this paper, a new modified system for equal power division is implemented with the help of rectangular micro strip patch antenna, Gysel power divider and leakage cancellation circuit. Today’s world power division plays an important role in wireless application areas such as base stations, antenna arrays, handheld devices etc., Here micro strip patch antenna is implemented with FR4 as a substrate material due to its benefits such as low loss and low fabrication cost while the ground material is aluminium due to its conductivity. For a good system, the return loss should be highly desirable and insertion loss should be low. Our proposed system is designed with a combination of micro strip patch antenna, leakage cancellation circuit and Gysel power divider produces equal power division with low loss such as insertion loss is measured as -39.291dB, return loss as -16.11dB and leakage cancellation as 6dB which was designed and simulated in Agilent Advanced Design System software (2009).
DETECTION OF POWER-LINES IN COMPLEX NATURAL SURROUNDINGScsandit
Power transmission line inspection using Unmanned Aerial Vehicles (UAV) is taking off as an
exciting solution due to advances in sensors and flight technology. Extracting power-lines from
aerial images, taken from the UAV, having complex natural surroundings is a critical task in the
above problem. In this paper we propose an approach for suppressing natural surrounding that
leads to power line detection. The results of applying our method on real-life video frames taken
from a UAV demonstrate that our approach is very effective. We believe that our approach can
be easily used for line detection in any other real outdoor video as well.
Dynamic Beamforming Optimization for Anti-Jamming and Hardware Fault RecoveryJonathan Becker
In recent years there has been a rapid increase in the number of wireless devices for both commercial and defense applications. Such unprecedented demand has increased device cost and complexity and also added a strain on the spectrum utilization of wireless communication systems. This thesis addresses these issues, from an antenna system perspective, by developing new techniques to dynamically optimize adaptive beamforming arrays for improved anti-jamming and reliability.
Available frequency spectrum is a scarce resource, and therefore increased interference will occur as the wireless spectrum saturates. To mitigate unintentional interference, or intentional interference from a jamming source, antenna arrays are used to focus electromagnetic energy on a signal of interest while simultaneously minimizing radio frequency energy in directions of interfering signals. The reliability of such arrays, especially in commercial satellite and defense applications, can be addressed by hardware redundancy, but at the expense of increased volume, mass as well as component and design cost.
This thesis proposes the development of new models and optimization algorithms to dynamically adapt beamforming arrays to mitigate interference and increase hardware reliability. The contributions of this research are as follows. First, analytical models are developed and experimental results show that small antenna arrays can thwart interference using dynamically applied stochastic algorithms. This type of in-situ optimization, with an algorithm dynamically optimizing a beamformer to thwart interference sources with unknown positions, inside of a anechoic chamber has not been done before to our knowledge. Second, it is shown that these algorithms can recover from hardware failures and localized faults in the array. Experiments were performed with a proof-of-concept four-antenna array. This is the first hardware demonstration showing an antenna array with live hardware fault recovery that is adapted by stochastic algorithms in an anechoic chamber. We also compare multiple stochastic algorithms in performing both anti-jamming and hardware fault recovery. Third, we show that stochastic algorithms can be used to continuously track and mitigate interfering signals that continuously move in an additive white Gaussian noise wireless channel.
Narrowband Spectrum Sensing for Different Fading Channels for Cognitive Radio...IJMERJOURNAL
Abstract: Nowadays the demand of applications of wireless communication has increased rapidly which causes the scarcity of radio spectrum. To empower future wireless communication services, the radio spectrum management is a very important factor. Cognitiveradio is a promising technology which provides an innovative way to improve utilization efficiency of available electromagnetic spectrum by sensing spectrum and shares it without harmful interference to other users. Narrowband spectrum sensing is the technique where the bandwidth of active primary transmitter in the vicinity of cognitive radio is less than the coherence bandwidth of channel. Fading is one of the greatest impairment of narrowband spectrum sensing. It is deflection of the attenuation. It influences a signal over certain propagation media.A communication channel that experiences fading isknown as fading channel. The effects of fading can be reduced by several fading models. In this paper, performanceanalysis of several realistic fading models on narrowband channel using energy detection method is employed. Finally, performance comparison of various fading models is guaranteed through simulation.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Sidelobe rejection in a uniform linear array antenna using windowing techniqueseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Channel Overlapping Between IMT-Advanced Users and Fixed Satellite ServiceEECJOURNAL
The Novel technique to modulate the nulls in the radiation pattern of IMT-Advanced base station (BS) towards the fixed satellite service is (FSS) affirmed in this paper. Designing a new algorithm to extract the nulls in the forbidding area and other base on MUSIC algorithm to estimate the direction of mobile user and control the handover technique is our major concern. A scenario of two mobile users (MS) moving around one FSS had been exclusively studied and simulated. Calculating the shortest separation distance after identifying the critical point and compare the result with the recent recommendation had shown how magnificent coexistence and spectrum sharing we can get.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
BER Performance of Antenna Array-Based Receiver using Multi-user Detection in...ijwmn
Antenna promises to provide significant increases in system capacity and performance in
wireless systems. In this paper, a simplified, near-optimum array receiver is proposed,
which is based on the angular gain of the spatial filter. This detection is then analyzed by
calculating the exact error probability.The proposed model confirms the benefits of adaptive
antennas in reducing the overall interference level (intercell/intracell) and to find an
accurate approximation of the error probability. We extend the method that has been
proposed for propagation over Nakagami-m fading channels, the model shows good
agreements with simulation results.
Simulation of an adaptive digital beamformer using matlabIJARBEST JOURNAL
Beam forming is the process of combining the weighted signals received on an array of
sensors to improve the directionality. Adaptive beamforming is the ability of the beamformer to
receive the signal only from the desired direction and to reject all other signals from undesired
directions. The weight vector for the adaptive beamformer continuously changes based on some
adaptive algorithm. Therefore, adaptive digital beam formers can point the antenna to the signal
direction without changing the physical architecture of the array antenna. The beam pointing
direction can be varied electronically with this technique. This paper focuses on Least Mean
Square (LMS) adaptive algorithm.
Smart Antenna is a device with signal processing
capability combining multiple antenna elements to optimize its
radiation and reception patterns as per designed specifications.
Smart antennas basically comprise of two functionalities, i.e.,
Direction of Arrival and Beamforming. This paper explains the
estimation of Direction of Arrival using MLM method and a
novel approach called MUltiple Signal Classification which takes
advantage of orthogonal property and performs subspace
computation. With a comparative study of both the algorithms,
we shall prove the advantages of MUltiple Signal Classification
over the MLM method with the aid of MATLAB
A Novel Approach for Interference Suppression Using a Improved LMS Based Adap...IJRST Journal
A novel adaptive beam forming technique is proposed for wireless communication applications based on the minimum bit error rate (MBER) criterion known as LMS algorithm. LMS (Least Mean Square) algorithm is used for steering the antenna beam electronically. Using the Rectangular, Hamming, Kaiser, Chebyshev windows both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed. By making use of window techniques half power beam width of an antenna is enhanced using Matlab simulation. The gain of the system will definitely improve the performance of CDMA based system, where the number of interferes is quite large and helps to increase the spectral efficiency of wireless communication systems. Any beam former that can depress the large number of interferers will improve the capacity and performance. Such beam formers are called smart antennas. They improve signal to interference ratio (SIR) of the communication system efficiently by forming narrow beam towards desired user and low side towards undesired users. Smart antennas offer a broad range of ways to improve wireless system performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
2. World Appl. Sci. J., 6 (6): 754-758, 2009
areas of radar, sonar, medical imaging location based RESULTS AND DISCUSSION
application and communications. Smart antennas have
the property of spatial filtering, which makes it possible Simulation for 8 elements Antenna Array is performed
to receive energy from a particular direction while on Matlab 7.0, using input Signal consisting of user
simultaneously blocking it from another direction. This signal at 0 degree, three Gaussian Interferers at -60, -30
property makes smart antennas as a very effective tool in and 60 degree and White Gaussian Noise at each element
detecting and locating radiation from other sources with SNR of 10 dB is added. Modulation environment
[15, 16]. Smart antennas are characterized into switched is MSK (Minimum Shifting Key). User signal is taken
beam system and adaptive arrays. In this paper adaptive from randint and normnd commands of Matlab that
arrays are investigated and used for smart antenna model. have an equal probability of having 0’s and 1’s.
In adaptive beamforming, the goal is to adapt the beam by The beampattern is obtained by first calculating an
Array factor for the array from -180 to 180 degrees and
adjusting the gain and phase on each antenna element
then multiplying the weights with it. The response of
such that a desirable pattern is formed.
every input user signal and interfering signal is shown in
the form of a graphical user interface in Figure 1. It can be
MATERIALS AND METHODS
seen that main lobe is formed towards user at angle 0 and
interfering signals at -60, 30 and 60 degrees are being
The output response of the uniform linear array is rejected as nulls are placed towards them. Response is
given by LMS as follows: calculated for LMS, RLS and CMA. It is also revealed that
by selecting larger array of antenna elements, element
y(n)= wH x(n) (1) spacing increases. Major drawback of this approach lies
in appearance of replicas of main lobe in undesired
where w is the complex weights vector and x is the directions, referred to as grating lobes.
received signal vector Amplitude response is obtained by taking 20log10 of
Optimal weights are calculated as follows: the values obtained during beam pattern (Figure 2).
From Amplitude response it is also clear that main lobe
w (n+1) = w(n)- µ g(w(n)) (2) is formed best from RLS and LMS Algorithms as it has
maximum signal strength in user direction. While
where w(n+1) denotes new weights computed at interference rejection is better in CMA as it can be seen
(n+1) iteration. ì is gradient step size that controls the that it is producing nulls towards interfering signals.
convergence characteristics of the algorithm, that is how By giving different angles to user signal and interference
fast and close the estimated weights approach the optimal the amplitude response changes accordingly.
weights g(w(n)) is estimate of gradient of the Mean The BER is obtained by first demodulating the
Square Error (MSE); output signal (that was modulated in Minimum Shifting
Keying environment) to obtain the bits that were present
MSE(w(n))=E[3r(n+1)ï²]+ wH (n)R w(n)-2 wH(n)z (3) in demodulated signal. Then these bits have been
subtracted from the bits of original signal values.
Modulus of this subtraction gives the BER values.
Errors between reference signal and array output
The high error rate in single antenna element is due
have been calculated using standard methods. In RLS,
to the fact that it would have to provide coverage to
3 from LMS is replaced by gain matrix, weight vector and
enhanced number of users, which are much more than its
error signal are calculated using standard methods. In
capacity so error rate increases. CMA is Blind Sequence
CMA we don’t have any reference signal as it is blind
algorithm that does not require any training bits and it
beamforming algorithm, so error signal is defined as
gives relatively less BER.
follows; LMS is training sequence Algorithm that requires
reference signal to compare with input signal so it lessons
ε (n) = y ( n)
− y (n) BER. It has been revealed from different simulation
y ( n) (4) measurements that RLS gives best results. It can be seen
that BER is maximum for a single antenna element and
Weights have been updated using standard methods BER reduces by using smart antenna system having
of CMA. Adaptive Algorithms.
755
3. World Appl. Sci. J., 6 (6): 754-758, 2009
Fig. 1: Beampattern, User at Angle 0, and Interferers at Angles 60, 30, 60
Fig. 2: Amplitude Responses, User at Angle 0, Interferers at -60, 30, 60
756
4. World Appl. Sci. J., 6 (6): 754-758, 2009
The error plot is drawn by subtracting original signal CONCLUSION
from output signal. Its magnitude has been calculated to
draw the plot. It has been observed that increasing the In a comprehensive comparison among adaptive
value of SNR error decreases. Minimum error has been algorithms, the parameters of beampattern, amplitude
noticed from RLS and maximum error from CMA. Many response, error plot and BER have been studied. The
algorithms may perform poorly or fail completely in the system has also been analyzed in strict SNR environment.
field because the assumptions made in the mathematical The significance of LMS algorithm cannot be ruled out
models do not accurately represent the real physics of in generating better main lobe in a specified direction of
the problem at hand. So it is further recommended for user but to nullify co channel interference it plays very
operators to verify performance in real life also. By unsatisfactory response. CMA bears maximum error but
increasing the number of elements in the Antenna Array focusing on co channel interference it gives more reliable
results than LMS and RLS. Results obtained from
(from 8 to 12 in this case) the Beams become narrow.
simulation assert that capability to reject the interfering
The most exciting contribution of smart antennas in
signal by placing nulls in undesirable direction is
communication technology lies in its narrow beam
really accomplished by CMA. But when angle of arrival of
features that enhances directional gain and intensity and
interference and user were quite close to each other then
the user can be facilitated with maximum signal
CMA had BER even more than single antenna element.
strength. On operator end it also saves power because a RLS algorithm involves more computations than LMS, it
narrow beam consumes less power than a broad beam. provides safe side towards main lobe and have better
By comparing amplitude responses from Figure 2, it is response towards co channel interference. It has been
ascertained as well that beam size is reduced when we revealed as well that convergence rate of RLS is faster
increase antenna array. The worst condition of SNR for than LMS. RLS Algorithm is found to have minimum BER
performance comparison has been considered as well. and error signal magnitude, therefore it has been proved
The SNR has been reduced from 10 to 2 db, interference the best algorithm for implementation on Base Station
and user signals have been given angles quite close to Smart Antenna System.
each other that is a performance limiting factor for smart
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