Artykuły w czasopismach: „Adaptive antennas”

1

Bansal, Preeti, i Nidhi Chahal. "Smart Antennas for Various Applications". CGC International Journal of Contemporary Technology and Research 4, nr 2 (5.08.2022): 316–18. http://dx.doi.org/10.46860/cgcijctr.2022.07.31.316.

Pełny tekst źródła

Streszczenie:

The paper presents about smart antennas for advancement in wireless and mobile communication. Smart antennas also called adaptive array antennas with better signal processing & can be used to calculate beam forming vectors which helps in tracking & locating antenna beam of target. Smart antennas are helpful in health monitoring in covid-19 pandemic and provides better service quality. Smart antenna is one of the rising innovations which can satisfy the prerequisites. Smart antennas are being used for controlling, monitoring and analyzing real time systems for various applications In smart antennas spatial division of the signal is used as compared to spectrum division, it can be beneficial for improving the performance of wireless communication. This paper describes how switched beam & adaptive array antennas differ from basic antennas.

Style APA, Harvard, Vancouver, ISO itp.

2

Wang, Chaowei, Weidong Wang, Cheng Wang, Shuai Wang i Yang Yu. "A Fast Adaptive Receive Antenna Selection Method in MIMO System". International Journal of Antennas and Propagation 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/175783.

Pełny tekst źródła

Streszczenie:

Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO) systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

Style APA, Harvard, Vancouver, ISO itp.

3

M. Africa, Aaron Don, Rica Rizabel M. Tagabuhin i Jan Jayson S. D. Tirados. "Design and simulation of an adaptive beam smart antenna using MATLAB". Indonesian Journal of Electrical Engineering and Computer Science 21, nr 3 (10.03.2021): 1584. http://dx.doi.org/10.11591/ijeecs.v21.i3.pp1584-1593.

Pełny tekst źródła

Streszczenie:

Signals transmitted over a long range of distance may pass through several obstacles and scatter, taking multiple paths to reach the receiver. Beamforming antennas are controlled electronically to adjust the radiation pattern following the first received signal. This allows the antenna to maximize the received signal and consequently, suppress the interfering signals received. A smart antenna should be able to diminish noise, increase the signal to noise ratio, and have better system competence. The adaptive beam makes use of the spacing of the several antennas and the phase of the signal of each antenna array to control the shape and direction of the signal beam. This paper focuses on the use of smart antennas using an adaptive beam method as a better system for the transmission of signals. A simulation between the existing Omnidirectional antenna system and the smart antenna system will be made and compared. The paper will discuss the corresponding advantages that a smart antenna system has compared to the Omnidirectional antenna system.

Style APA, Harvard, Vancouver, ISO itp.

4

Rajitha, Datla, i Godi Karunakar. "Effect of chaos factor in radiation pattern in planner antenna arrays with chaos adaptive invasive weed optimization". Indonesian Journal of Electrical Engineering and Computer Science 27, nr 2 (1.08.2022): 692. http://dx.doi.org/10.11591/ijeecs.v27.i2.pp692-700.

Pełny tekst źródła

Streszczenie:

For mobile communication and spatial detection of antennas should have high directive radiation pattern, in this context pattern synthesis of planar circular antenna arrays is highly significant such design has been done inverse weed optimization. The basic objective e is to study invasive weed optimization in compression with modified chaotic adaptive invasive weed optimization. The focus of the study is the effect of chaotic factors suitable for sinusoidal mapping for chaos as applicable to the context of the design of antennas. Taking various numbers of elements of the antenna and the distance between the antenna’s radiation patterns are studied by varying chaos factors through MATLAB programming. It is found that the critical point of 2.3 for chaos factor makes the map enter into phase of chaos prior to the critical point is a phase of periodicity starting with chaos factor of 2. Below this value there is no chaos but a phase of convergence. These phases are useful having a trade of convergence and chaos. By varying the factor of chaos the impact on the radiation factor of non-uniform planar antennas has been found to give phases of convergence of chaos which are essential for making trade of between exploitation and exploration required in optimization.

Style APA, Harvard, Vancouver, ISO itp.

5

Ojaroudi Parchin, Naser, Haleh Jahanbakhsh Basherlou, Yasir Al-Yasir, Raed Abd-Alhameed, Ahmed Abdulkhaleq i James Noras. "Recent Developments of Reconfigurable Antennas for Current and Future Wireless Communication Systems". Electronics 8, nr 2 (26.01.2019): 128. http://dx.doi.org/10.3390/electronics8020128.

Pełny tekst źródła

Streszczenie:

Reconfigurable antennas play important roles in smart and adaptive systems and are the subject of many research studies. They offer several advantages such as multifunctional capabilities, minimized volume requirements, low front-end processing efforts with no need for a filtering element, good isolation, and sufficient out-of-band rejection; these make them well suited for use in wireless applications such as fourth generation (4G) and fifth generation (5G) mobile terminals. With the use of active materials such as microelectromechanical systems (MEMS), varactor or p-i-n (PIN) diodes, an antenna’s characteristics can be changed through altering the current flow on the antenna structure. If an antenna is to be reconfigurable into many different states, it needs to have an adequate number of active elements. However, a large number of high-quality active elements increases cost, and necessitates complex biasing networks and control circuitry. We review some recently proposed reconfigurable antenna designs suitable for use in wireless communications such as cognitive-ratio (CR), multiple-input multiple-output (MIMO), ultra-wideband (UWB), and 4G/5G mobile terminals. Several examples of antennas with different reconfigurability functions are analyzed and their performances are compared. Characteristics and fundamental properties of reconfigurable antennas with single and multiple reconfigurability modes are investigated.

Style APA, Harvard, Vancouver, ISO itp.

6

Maruti Rajaram Jadhav, Maruti Rajaram Jadhav. "Navigating The Complexity Overcoming Mobility Obstacles in Massive MIMO Systems with MIMO Antennas." International Journal on Recent and Innovation Trends in Computing and Communication 11, nr 9 (30.11.2023): 4912–21. http://dx.doi.org/10.17762/ijritcc.v11i9.10087.

Pełny tekst źródła

Streszczenie:

This research investigates the synergy between Massive Multiple Input, Multiple Output (MIMO) systems and mobility challenges, with a focus on the pivotal role played by Multiple Antenna Systems (MIMO antennas). Employing a sophisticated experimental setup featuring a 3.5 GHz Massive MIMO base station equipped with 64 MIMO antennas, mobile terminals on motorized platforms, and advanced RF measurement tools, the study explores adaptive beamforming, spatial multiplexing, and diversity techniques. Results from 100 experiments, each lasting 10 minutes, reveal that adaptive beamforming dynamically improves user tracking in response to mobility-induced channel variations. Spatial multiplexing and diversity techniques enhance throughput and reliability, especially in high user mobility scenarios. The quantitative findings align with existing literature, providing practical insights for the deployment of MIMO antennas. The study addresses limitations and proposes avenues for future research, enhancing our understanding of MIMO antenna applications and contributing to the evolution of wireless communication technologies in dynamic environments.

Style APA, Harvard, Vancouver, ISO itp.

7

Easa,, Haider, Musa Wali i Adheed Sallomi. "Cellular Networks Pollution Reduction". Al-Kitab Journal for Pure Sciences 2, nr 2 (30.12.2018): 84–95. http://dx.doi.org/10.32441/kjps.02.02.p6.

Pełny tekst źródła

Streszczenie:

The potential of adaptive antennas to optimize the wireless network performance make it one of the promising technologies that can face the increased demand for wireless communications services with the limited available bandwidth. Adaptive antennas have the ability to steer their main lobe in the direction of interest and placing nulls in the direction of interference. This can result in co-channel interference minimization, maximizing Signal to Interference Ratio (SIR) and then improve the receiver sensitivity. In this paper, the base-station sensitivity improvement and its effect on the mobile transmit power were investigated at different scenarios. Results show that using adaptive antenna yields in RF pollution reduction.

Style APA, Harvard, Vancouver, ISO itp.

8

Wnuk, Marian. "Adaptive Antenna Array Control Algorithm in Radiocommunication Systems". Algorithms 17, nr 2 (14.02.2024): 81. http://dx.doi.org/10.3390/a17020081.

Pełny tekst źródła

Streszczenie:

An important element of modern telecommunications is wireless radio networks, which enable mobile subscribers to access wireless networks. The cell area is divided into independent sectors served by directional antennas. As the number of mobile network subscribers served by a single base station increases, the problem of interference related to the operation of the radio link increases. To minimize the disadvantages of omnidirectional antennas, base stations use antennas with directional radiation characteristics. This solution allows you to optimize the operating conditions of the mobile network in terms of reducing the impact of interference, better managing the frequency spectrum and improving the energy efficiency of the system. The work presents an adaptive antenna algorithm used in mobile telephony. The principle of operation of adaptive systems, the properties of their elements and the configurations in which they are used in practice are described. On this basis, an algorithm for controlling the radiation characteristics of adaptive antennas is presented. The control is carried out using a microprocessor system. The simulation model is described. An algorithm was developed based on the Mathcad mathematical program, and the simulation results of this algorithm, i.e., changes in radiation characteristics as a result of changing the mobile position of subscribers, were presented in the form of selected radiation characteristics charts.

Style APA, Harvard, Vancouver, ISO itp.

9

Africa, Aaron Don Munsayac, Benjamin Emmanuel Uy i Bianca Clarisse Tan. "Simulations on the effects of an optimized bowtie dipole antenna with an adaptive FIR filter". Bulletin of Electrical Engineering and Informatics 12, nr 3 (1.06.2023): 1550–59. http://dx.doi.org/10.11591/eei.v12i3.4406.

Pełny tekst źródła

Streszczenie:

In the evolution of technology through the years, antennas are use in varying wireless systems have been in demand. Antennas play a great role in transmitting and receiving signals. As its application is heavily used in many days to day activities, it is important to create a cost-efficient and quick way to analyze its performance, characteristics, and relationship to different variables. As many radiation pattern acquisition devices are expensive, this simulation proposes a quick, reliable, and cost-friendly way to simulate 2D patterns in the E-plane and H-plane of a bowtie dipole antenna with an adaptive finite impulse response (FIR) filter. Through this study, the software MATLAB will be utilized to successfully simulate the radiation patterns of antennas with varying lengths. With the use of MATLAB toolboxes, the researchers aim to be able to compare different antenna lengths and determine the relationship and effect of it in the obtained 2D radiation pattern. If this method is successful various antenna applications may be implemented in the future with the use of 2D radiation pattern results.

Style APA, Harvard, Vancouver, ISO itp.

10

So, Hideya, Kouhei Suzaki i Daisuke Goto. "Undesired Radiation Suppression Technique with Adaptive Control for Distributed Array Antenna Systems in Mobile Environment". Journal of communications software and systems 16, nr 2 (11.05.2020): 163–69. http://dx.doi.org/10.24138/jcomss.v16i2.1044.

Pełny tekst źródła

Streszczenie:

We have proposed a distributed array antenna (DAA) system for high-speed satellite communications. The DAA system uses multiple small tracking antennas and combines the transmission signals in-phase to increase the antenna gain. DAA system has a problem that the undesired radiation at the sidelobe direction increases as the antenna gain at the main lobe direction increases. In the mobile environment, the conventional technique can suppress the undesired radiation in the limited condition because of changing the direction of the undesired radiation according to the movement of the mobile station. This paper proposes a DAA technique that suppresses the undesired radiation by setting a transmission plate at each antenna aperture and moving them via adaptive control. The transmission plate consisting of a metal patch or slot retransmits electromagnetic waves and changes the amplitude and phase of the waves. To change the radiation patters of each antenna, the transmission plate rotates according to movement of the mobile station. After combining these changed signals, the adaptive control selects the rotate angle of the transmission plate to decrease the undesired radiation at the sidelobe direction. The antenna gain on the main lobe direction after combining is achieved with lower loss because the insertion loss through the transmission plate is smaller. The proposed technique offers more than $2.4$ dB improvement with three antennas and more than $3.5$ dB improvement with four antennas assuming each consists of $8 ¥times 8$ patches.

Style APA, Harvard, Vancouver, ISO itp.

11

Makoveenko, D. O., S. V. Siden i V. V. Pyliavskyi. "USE OF ADAPTIVE ANTENNA ARRAYS FOR INCREASE THE THROUGHPUT IN LTE-A". Radio Electronics, Computer Science, Control, nr 3 (6.10.2021): 17–25. http://dx.doi.org/10.15588/1607-3274-2021-3-2.

Pełny tekst źródła

Streszczenie:

Context. The aim of the article is to analyze the throughput of the LTE-A mobile network on the uplink using an adaptive linear equidistant antenna array. Objective. Suggestions have been made for the possibility of using adaptive antenna arrays to increase bandwidth in LTE-A mobile networks and analyze the benefits of its use compared to the standard type of base station antenna Method. To achieve this result, a computer model of noise analysis of the mobile network in the form of a flat regular hexagonal antenna array consisting of 7 three-sector cells was developed. To estimate the benefit from the use of adaptive antenna arrays, two options were analyzed: when using a standard antenna array of the LTE-A network, and an adaptive linear equidistant antenna array. During the simulation, 100 random placements of subscribers of useful and interference signals were performed and the minimum, maximum and average gain from the use of adaptive antenna arrays was calculated. The average value of the gain for the adaptive antenna array in the direction of the subscriber station, which generates a useful signal of 5.69 dB more than the standard antenna array of the LTE-A network. At the same time, there is a significant reduction in the gain of the adaptive antenna in the direction of the interference subscriber stations, namely, for those with the highest interference level, the gain is 32.84 dB and 28.33 dB, respectively. To clearly show the gain in the qualitative characteristics of the network, a bandwidth analysis was performed for different types of antennas. The bandwidth distribution (transport block size) for 50 resource blocks using an adaptive equidistant linear antenna array compared to a standard antenna array is presented. Results. It is shown that due to the use of adaptive antenna systems, the average bandwidth increases from 11 Mbit/s to 35 Mbit / s for all types of distribution considered channels. Conclusions. The article proposes the use of adaptive antenna arrays to increase the bandwidth of the LTE-A network. The simulation of bandwidth for 50 resource blocks showed that in the presence of internal system interference when using standard antennas of base stations, the average bandwidth is from 11.2 Mbps to 12.3 Mbps. At the same time, due to the use of adaptive antenna systems, the average bandwidth increases from 11 Mbit/s to 35 Mbit/s for all types of multipath channels considered.

Style APA, Harvard, Vancouver, ISO itp.

12

Asaly, Saed, Boaz Ben-Moshe i Nir Shvalb. "Accurate 3D Mapping Algorithm for Flexible Antennas". International Journal of Antennas and Propagation 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/3748623.

Pełny tekst źródła

Streszczenie:

This work addresses the problem of performing an accurate 3D mapping of a flexible antenna surface. Consider a high-gain satellite flexible antenna; even a submillimeter change in the antenna surface may lead to a considerable loss in the antenna gain. Using a robotic subreflector, such changes can be compensated for. Yet, in order to perform such tuning, an accurate 3D mapping of the main antenna is required. This paper presents a general method for performing an accurate 3D mapping of marked surfaces such as satellite dish antennas. Motivated by the novel technology for nanosatellites with flexible high-gain antennas, we propose a new accurate mapping framework which requires a small-sized monocamera and known patterns on the antenna surface. The experimental result shows that the presented mapping method can detect changes up to 0.1-millimeter accuracy, while the camera is located 1 meter away from the dish, allowing an RF antenna optimization for Ka and Ku frequencies. Such optimization process can improve the gain of the flexible antennas and allow an adaptive beam shaping. The presented method is currently being implemented on a nanosatellite which is scheduled to be launched at the end of 2018.

Style APA, Harvard, Vancouver, ISO itp.

13

Hur, Byul, William R. Eisenstadt i Kathleen L. Melde. "Testing and Validation of Adaptive Impedance Matching System for Broadband Antenna". Electronics 8, nr 9 (19.09.2019): 1055. http://dx.doi.org/10.3390/electronics8091055.

Pełny tekst źródła

Streszczenie:

Broad RF impedance matching is challenging; however, the need for broadband matching is found frequently in modern RF and wireless systems with multiple wireless standards. Moreover, in 5G technology, multiple frequency bands are used, and these systems typically employ a broadband antenna or multiple antennas. Antenna impedances vary from design targets for many reasons including manufacturing process variations or antenna environment changes. An adaptive impedance matching system (AIMS) for testing and validation is introduced, and its implementation is shown in this paper. The AIMS can control impedance matching tuner settings to provide an arbitrary impedance frequency-varying load that meets user-defined conditions. This AIMS provides a testing and validation system for broadband antennas that can be characterized by various settings of the impedance matching tuner. As a device under test (DUT), a three-stub reconfigurable filter was used as the impedance matching tuner on a RT/Duroid 6010 RF board. It was integrated with a control circuit board. This AIMS implementation also included an antenna impedance tuner that can vary the distance between the antenna and the ground plane. This model represents practical antenna impedance variations. The AIMS controls a network analyzer and the impendence matching tuner. The adaptive control program on a PC was developed to perform an effective two-pass tuning strategy. This article presents the successful automated tuned results and their numerical evaluations of three cases that were generated by the antenna impedance tuner.

Style APA, Harvard, Vancouver, ISO itp.

14

Africa, Aaron Don M., Rica Rizabel M. Tagabuhin i Jan Jayson Tirados. "Development of a design optimization algorithm for a bowtie antenna". Indonesian Journal of Electrical Engineering and Computer Science 31, nr 1 (1.07.2023): 229. http://dx.doi.org/10.11591/ijeecs.v31.i1.pp229-237.

Pełny tekst źródła

Streszczenie:

A bowtie antenna is one of the simple dipole antennas with an omnidirectional pattern utilized in several applications. It is used in industrial applications, scientific applications, and medical applications. Its elementary design can be subjected to modification to expand the applications of the dipole and improve its performance. This paper aims to develop a design optimization algorithm for a bowtie antenna with an adaptive finite impulse response (FIR) filter. In the paper, the different designs of the bowtie antenna are simulated using MATLAB software. The design of antennas is constructed using the partial differential equation (PDE) toolbox in MATLAB software. The designs explored in the paper are the slotted microstrip bowtie antenna and the double flare bowtie antenna. A traditional bowtie was also simulated to be used as a reference for the evaluation of the modified antennas. The dimensions of the designs are kept closely like draw accurate conclusions about the effects of the refinements done. The effects of the modification of the designs on the directivity and return loss are determined to assess the effectiveness of the design alterations.

Style APA, Harvard, Vancouver, ISO itp.

15

Shcherbyna, Olga, Maksym Zaliskyi, Olena Kozhokhina i Felix Yanovsky. "Prospect for Using Low-Element Adaptive Antenna Systems for Radio Monitoring Stations". International Journal of Computer Network and Information Security 13, nr 5 (8.10.2021): 1–17. http://dx.doi.org/10.5815/ijcnis.2021.05.01.

Pełny tekst źródła

Streszczenie:

This article is devoted to the analysis of prospect to apply multifunctional adaptive antenna systems for radio monitoring stations. The review of publications done demonstrates that current antennas that are developed and used in radio monitoring systems to control and measure the parameters of electromagnetic radiation should be applicable to conduct accurate measurements in wide frequency range under the condition of interferences. The analysis shows that modern adaptive antenna systems are mostly developed for radar and telecommunications applications. In this context we consider possible ways to solve the problem of adapting radio monitoring devices to a complex electromagnetic environment using antenna systems with primary processing of received signals . It was found that the developers of the antennas, which are based on adaptive interference suppression methods, focus basically on the development and implementation of adaptation processes, limiting themselves only to solving electromagnetic compatibility problems. In such approach, the functions of direction finding and measurement of radiation field parameters important exactly for radio monitoring systems are mostly ignored. Therefore, this research area opens up a wide field for identifying new possibilities for constructing multifunctional antenna systems. Focusing on this direction of research, we consider as an example the constraction of a simple two-element adaptive antenna system, which can be used to measure the parameters of the electromagnetic field in radio monitoring systems. The main relations for the error of determining the direction of arrival of the interference signal with a simple two-element antenna are investigated. The influence of the stability of the antenna array parameters and functional units of signal processing onto the errors is estimated.

Style APA, Harvard, Vancouver, ISO itp.

16

Park, Hyunhee, Taeshik Shon, Seunghyun Park i Eui-Jik Kim. "An Adaptive Allocation Algorithm Using Directional CSMA/CA over mmWave Wireless Personal Area Networks". International Journal of Advanced Robotic Systems 9, nr 1 (1.01.2012): 17. http://dx.doi.org/10.5772/50914.

Pełny tekst źródła

Streszczenie:

Directional antennas have the considerable benefits of higher antenna gain, long transmission distance and spatial reuse compared to omni-antennas. To support a directional antenna, IEEE 802.15.3c specifies a high data transmission rate and short frequency range communication based on the characteristics of 60GHz band. However, the contention-based protocol of IEEE 802.15.3c may cause channel collisions and throughput degradation as the number of stations in the network increases. In order to resolve this problem and reduce channel access latency, we propose an adaptive allocation algorithm in which the contention window size for optimal transmission probability is derived after the directional information has been obtained by means of AP control procedures. Extensive simulations demonstrate that the proposed algorithm outperforms the existing channel access scheme in IEEE 802.15.3c wireless personal area networks under different situations, especially when the number of contending stations is large.

Style APA, Harvard, Vancouver, ISO itp.

17

De Nicola, Silvio, Antonio De Maio, Alfonso Farina, Michele Fiorini, Leopoldo Infante i Marco Piezzo. "Effects of Mutual Coupling of Radiating Antennas on an Adaptive Radar Detector". International Journal of Electronics and Telecommunications 57, nr 4 (1.12.2011): 451–57. http://dx.doi.org/10.2478/v10177-011-0063-2.

Pełny tekst źródła

Streszczenie:

Effects of Mutual Coupling of Radiating Antennas on an Adaptive Radar Detector In this paper, we address the adaptive detection/classification of signals in a homogenous interference environment. We refer to a radar system equipped with a phased array antenna and account for both the presence of mutual coupling between radiating antennas and a possible coherent interferer impinging on the array mainbeam. To deal with this scenario, we adopt a two-stage detection/classification scheme, enjoying the Costant False Alarm Rate (CFAR) property, to discriminate between target detection and coherent interferer rejection. Finally, we evaluate the system performance via Monte Carlo simulations. The results show that our system has interesting rejection capabilities and satisfactory detection levels. As a consequence, it could be successfully applied in real scenarios where mutual coupling is present.

Style APA, Harvard, Vancouver, ISO itp.

18

Sallam, Tarek Abdel Rahman, Adel Bedair Abdel-Rahman, Masoud Alghoniemy i Zen Kawasaki. "Flower Pollination Algorithm for Adaptive Beamforming of Phased Array Antennas". Journal of Machine Intelligence 2, nr 2 (15.12.2017): 1–5. http://dx.doi.org/10.21174/jomi.v2i2.71.

Pełny tekst źródła

Streszczenie:

This paper introduces the flower pollination algorithm (FPA) as an optimization technique suitable for adaptive beamforming of phased array antennas. The FPA is a new nature-inspired evolutionary computation algorithm that is based on pollinating behaviour of flowering plants. Unlike the other nature-inspired algorithms, the FPA has fewer tuning parameters to fit into different optimization problems. The FPA is used to compute the complex beamforming weights of the phased array antenna. In order to exhibit the robustness of the new technique, the FPA has been applied to a uniform linear array antenna with diﬀerent array sizes. The results reveal that the FPA leads to the optimum Wiener weights in each array size with less number of iterations compared with two other evolutionary optimization algorithms namely, particle swarm optimization and cuckoo search.

Style APA, Harvard, Vancouver, ISO itp.

19

Chougule, Rutuja. "Smart Antenna Systems". International Journal for Research in Applied Science and Engineering Technology 10, nr 6 (30.06.2022): 1182–86. http://dx.doi.org/10.22214/ijraset.2022.43988.

Pełny tekst źródła

Streszczenie:

Abstract: Smart antennas have received increasing interest for improving the performance of wireless radio systems. These systems of antennas include a large number of techniques that attempt to enhance the received signal, suppress all interfering signals, and increase capacity, in general. The main purpose of this article is to provide an overview of the current state of research in the area of smart antennas, and to describe how they can be used in wireless systems. A smart antenna takes advantage of diversity effect at the source (transmitter), the destination (receiver), or both. Diversity effect involves the transmission and/or reception of multiple radio frequency (RF) waves to increase data speed and reduce the error rate. Thus, this article provides a basic model for determining the angle of arrival for incoming signals, the appropriate antenna beamforming, and the adaptive algorithms that are currently used for array processing. Moreover, it is shown how smart antennas, with spatial processing, can provide substantial additional improvement when used with TDMA and CDMA digitalcommunication systems.

Style APA, Harvard, Vancouver, ISO itp.

20

Fan, Sen Quan, Yan Dong Huang, En Qing Xu, Kai Zhang, Hai Zhou Zhu, Hui Zhai i Nan Jiang. "An Adaptive Power Allocation for Spatial Multiplexing in MIMO Channels". Advanced Materials Research 756-759 (wrzesień 2013): 4179–83. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.4179.

Pełny tekst źródła

Streszczenie:

This paper proposes an adaptive power allocation in multiple-input multiple-output (MIMO) spatial multiplexing slow fading channels, which improves spectral efficiency and reduces the complexity of systems at the same time. Under the constraint of the same signal-to-interference and noise ratio (SINR) at each receive antenna, an iteration formula of power allocation algorithm for transmit antennas is derived. Besides, for a certain channel gain matrix, the same SINR value at each receive antenna is proved to have the limit value. The simulations of the proposed adaptive power allocation show that the algorithm is effective and can reach the convergence fast.

Style APA, Harvard, Vancouver, ISO itp.

21

G, Shivapanchakshari T., i H. S. Aravinda. "Adaptive Resource Allocation using various Smart Antenna Techniques to maintain better System Performance". International Journal of Engineering and Advanced Technology 8, nr 5s (29.06.2019): 262–65. http://dx.doi.org/10.35940/ijeat.e1052.0585s19.

Pełny tekst źródła

Streszczenie:

Smart antennas are capable of offering major contribution in improving system performance of orthogonal frequency division multiplexing (OFDM) systems. The OFDM is an air-link technology required for future wireless communication applications to address the technological challenges in fulfilling users demand. The adaptive resource allocation techniques in OFDM systems using smart antennas is an optimistic approach showing light towards developing various methods to improve spectral efficiency with required quality of service (QoS). However, fully adaptive techniques increase the challenges in designing the physical layer with minimum complexity. Now, the challenge is to investigate the possibility of achieving satisfactory system performance without increasing complexity at MAC layer of next generation OFDM systems. In this paper, methodology of designing a hybrid smart antenna system is proposed to achieve required QoS with minimum system complexity.

Style APA, Harvard, Vancouver, ISO itp.

22

Haupt, R. L. "Adaptive nulling in monopulse antennas". IEEE Transactions on Antennas and Propagation 36, nr 2 (1988): 202–8. http://dx.doi.org/10.1109/8.1097.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

23

Barrett, M., i R. Arnott. "Adaptive antennas for mobile communisations". Electronics & Communication Engineering Journal 6, nr 4 (1.08.1994): 203–14. http://dx.doi.org/10.1049/ecej:19940404.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

24

Brookner, Eli. "Adaptive antennas, concepts and performance". IEEE Antennas and Propagation Society Newsletter 30, nr 5 (październik 1988): 37. http://dx.doi.org/10.1109/map.1988.6086113.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

25

Jiayuan, Hu, i Zhong Haibin. "Kalman filter for adaptive antennas". Wuhan University Journal of Natural Sciences 3, nr 2 (czerwiec 1998): 187–91. http://dx.doi.org/10.1007/bf02827549.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

26

Tyler, N., B. Allen i H. Aghvami. "Adaptive antennas: the calibration problem". IEEE Communications Magazine 42, nr 12 (grudzień 2004): 114–22. http://dx.doi.org/10.1109/mcom.2004.1367563.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

27

Al-Omary, Alauddin. "End-to-End Performance Evaluation for MIMO-OSTBC Adaptive Modulation Over Rayleigh Fading Channel". International Journal of Engineering & Technology 7, nr 3.13 (27.07.2018): 8. http://dx.doi.org/10.14419/ijet.v7i3.13.16314.

Pełny tekst źródła

Streszczenie:

This paper presents end-to-end performance evaluation for adaptive Orthogonal Space-Time Block Codes (OSTBC) Multiple Input Multiple Output (MIMO) communication system over frequency selective Rayleigh fading channel. The system operates with one, two, three or four transmit or receive antennas to transmit and receive any frame. The system uses an adaptation algorithm that dynamically adjusts the used number of transmit and receive antennas based on the difference between the target and actual frame-error rates (FER) of the overall system. In this way, the performance of the system can be controlled adaptively. Alamouti and other adaptation algorithms are implemented in this system. The results show that FER improve significantly as the SNR increases and when the SNR is small, the adaptive algorithms successfully adjust the use of MIMO antenna to compensate the impairment caused by the faded and noisy channel.

Style APA, Harvard, Vancouver, ISO itp.

28

Liu, Han, Chengyou Yin, Weidong Gao i Yulong Sun. "Optimization and Design of Wideband Antenna Based onQFactor". International Journal of Antennas and Propagation 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/971646.

Pełny tekst źródła

Streszczenie:

A wideband antenna is designed based onQfactor in this paper. Firstly, the volume-surface integral equations (VSIEs) and self-adaptive differential evolution algorithm (DEA) are introduced as the basic theories to optimize antennas. Secondly, we study the computation ofQof arbitrary shaped structures, aiming at designing an antenna with maximum bandwidth by minimizing theQof the antenna. This method is much more efficient for onlyQvalues at specific frequency points that are computed, which avoids optimizing bandwidth directly. Thirdly, an integrated method combining the above method with VSIEs and self-adaptive DEA is employed to optimize the wideband antenna, extending its bandwidth from 11.5~16.5 GHz to 7~20 GHz. Lastly, the optimized antenna is fabricated and measured. The measured results are consistent with the simulated results, demonstrating the feasibility and effectiveness of the proposed method.

Style APA, Harvard, Vancouver, ISO itp.

29

Qasim, Aseel Abdul-Karim, Adheed Hassan Sallomi i ِAli Khalid Jassim. "Rabid Euclidean direction search algorithm for various adaptive array geometries". Bulletin of Electrical Engineering and Informatics 10, nr 2 (1.04.2021): 856–69. http://dx.doi.org/10.11591/eei.v10i2.1899.

Pełny tekst źródła

Streszczenie:

One of the exciting technologies used to meet the increasing demand for wireless communication services is a smart antenna. A smart antenna is basically confirmed by an array of antennas and a digital beamformer unit through which cellular base station can direct the beam toward the desired user and set nulls toward interfering users. In this paper, different array configurations (linear, circular, and planer) with the REDS algorithm are implemented in the digital beam-forming unit. The wireless system performance is investigated to check the smart antenna potentials assuming Rayleigh fading channel environment beside the AWGN channel. Results show how the REDS algorithm offers a significant improvement through antenna radiation pattern optimization, sidelobe level, and interference reduction, and also the RDES algorithm proves fast convergence with minimum MSE and better sidelobe level reduction comparing with other algorithms.

Style APA, Harvard, Vancouver, ISO itp.

30

Ho, Min-Che, Pin-Yu Song, Yi-Shian Chiou, Yueh-Tan Lee i Li-Ling Huang. "Optimization of Coverage and Capacity Using Smart Antennae". Applied Sciences 13, nr 19 (30.09.2023): 10897. http://dx.doi.org/10.3390/app131910897.

Pełny tekst źródła

Streszczenie:

In the rural and geographically remote regions of Taiwan, the high cost of establishing information infrastructure has resulted in significantly lower internet penetration and usage rates compared with urban areas. To address the network demands in such remote mountainous areas, the deployment of multiple mobile base stations has become essential. However, the wireless implementation of base stations can lead to signal interference issues. This research aims to enhance the signal reception capabilities of end-user devices by utilizing intelligent directional antennas. This study employs five directional smart antennas, each of which can be independently adjusted to be active or inactive. Unlike traditional omnidirectional antennas that cause interference in overlapping coverage areas for end-user devices, our proposed adaptive directional antenna algorithm optimizes energy consumption by selectively activating directional antennas and concurrently reduces signal interference problems for end-user devices. The results of this research offer valuable insights for improving network connectivity and efficiency in remote and underserved areas. Through experimental simulations conducted in an environment with 10 base stations per square kilometer, the utilization of smart antennas, as opposed to omnidirectional antennas, results in a significant improvement of 33.8% in signal coverage.

Style APA, Harvard, Vancouver, ISO itp.

31

Dr. Joy Chen i Lu-Tsou Yeh. "Adaptive Array Processing based Wireless Energy Transmission for IoT Applications". IRO Journal on Sustainable Wireless Systems 2, nr 3 (2.01.2021): 128–32. http://dx.doi.org/10.36548/jsws.2020.3.004.

Pełny tekst źródła

Streszczenie:

Rechargeable energy sources are essential for the extreme deployment of Internet-of-Things (IoT) sensors with the massive growth in smart systems. In order to meet these requirements, wireless energy transmission (WET) provides demand based power to the sensors. Temporary energy storage is done using supercapacitors. This overcomes the drawback of release of hazardous wastes released by IoT connected disposables after their working life. WET is made possible through adaptive array processing. The system consists of a transmitting side with multiple antennas and a receiving side with a programmable energy harvester. Several far-field adaptive processing schemes such as conventional beamformers, multiple sidelobe canceller (MSLC), multiple beam antenna system, regenerative hybrid array, digital beamformer, and generalized sidelobe canceller are tested and compared with the proposed modified beamforming model for superior performance. As the number of antennas increases, the gain increases. Gain and cumulative distribution function are analyzed over multiple distances for multiple iterations. The received signal strength indicator (RSSI) is also estimated to validate the performance of the proposed model.

Style APA, Harvard, Vancouver, ISO itp.

32

Kusaykin, D. V., I. V. Grigoriev, D. V. Denisov i P. A. Turalchuk. "Review of Luneburg Lens Antenna Designs Manufactured Using 3D Printing". Journal of the Russian Universities. Radioelectronics 27, nr 2 (25.04.2024): 6–36. http://dx.doi.org/10.32603/1993-8985-2024-27-2-6-36.

Pełny tekst źródła

Streszczenie:

Introduction. The interest in multibeam dielectric lens antenna arrays has been growing in recent years due to the development of millimeter-wave telecommunication and radar systems. Progress in the development of mobile communication systems based on adaptive beamforming technology is increasingly associated with multibeam systems based on lens antenna structures, providing an alternative to hard-to-implement and energy-consuming phased antenna arrays. In recent years, spherical and cylindrical Luneburg lens antennas implemented using additive manufacturing technology have attracted research attention. Despite their complexity of execution, these design exhibit excellent electromagnetic characteristics. This paper provides a review of Luneburg lens antennas manufactured using 3D printing, which can find application in 5G and 6G communication systems.Aim. To review achievements in the design of lens antenna structures manufactured using additive manufacturing.Materials and methods. Materials for analysis, comparison, and systematization were derived from various sources, including research articles, publications in proceedings of Russian and international conferences, and websites of manufacturers of lens antennas over the past 20 years. The material selection mechanism was based on the originality of the presented designs of printed Luneburg lens antennas.Results. A review of Luneburg lens antennas manufactured using 3D printing, which differ from each other in terms of mechanical strength, complexity of execution, and electrodynamic characteristics, was carried out. The results of a comparative analysis of the key characteristics of these antennas are presented, along with examples of their practical implementation.Conclusion. The disadvantage of Luneburg lens antennas has always been the complexity of their manufacture; however, additive manufacturing technologies open up new opportunities for their fast, high-quality, and automated production. Various 3D printing technologies can be used to create dielectric lens antennas, which differ in the resolution of printers, printing speed, and cost. Additive manufacturing methods are constantly developing, having reached the technological possibility of printing Luneburg lens for the sub-THz range with a high level of resolution and accuracy. In addition, 3D printers capable of printing multiple lenses simultaneously have also appeared.

Style APA, Harvard, Vancouver, ISO itp.

33

Donelli, Massimo. "Reconfigurable Antenna Systems for the Next Generation Devices Based on 4G/5G Standard". International Journal of Interactive Communication Systems and Technologies 7, nr 2 (lipiec 2017): 53–71. http://dx.doi.org/10.4018/ijicst.2017070103.

Pełny tekst źródła

Streszczenie:

This article is devoted to showing the applications of innovative reconfigurable antenna systems suitable for the next generation 4G/5G devices. Microwave antenna technology can be very useful for next generation devices based on 4G/5G standards. Next generation tablets and smartphones based on 4G/5G standards will require high bandwidth and high velocity channels with respect to conventional devices. This work tries to present a complete overview of possible applications of advanced antenna technologies for 4G/5G devices and systems. Methodologies, such as phased and fully adaptive arrays, multiple-input and multiple-output (MIMO) antennas based on compact Rotman lenses or butler matrices, development of innovate reconfigurable antennas based on reconfigurable parasitic structures or new materials such as graphene, and unconventional modulation techniques have been investigated in this work. The work ends with some conclusions and considerations related to ideas for future works.

Style APA, Harvard, Vancouver, ISO itp.

34

Douksha, D. V., S. V. Liashkevich i V. A. Saetchnikov. "Development of an out-of-Focus Irradiator Based on a Phased Antenna Array for a Space Communications' Parabolic Reflector Antenna". Devices and Methods of Measurements 10, nr 3 (9.09.2019): 233–42. http://dx.doi.org/10.21122/2220-9506-2019-10-3-233-242.

Pełny tekst źródła

Streszczenie:

Mirror antenna systems are widely used in satellite and space communication systems and radio astronomy. Development of these areas requires new efficient antenna systems' design. Possible technical solution for creating an effective mirror antenna is a “hybrid” scheme, when an adaptive phased antenna array is used as an irradiator. This paper is devoted to the development of an out-of-focus irradiator based on a phased antenna array for a space communications' parabolic reflector antenna. The aim of the work is to develop an optimal design of the irradiator with the choice of the structural element of the antenna array and experimental studies of the selected structural element.The wavefront recovery method was used as a tool for selecting the irradiator configuration. The idea of this method use is to reproduce the electromagnetic field of an incident plane wave with an irradiator in order to uniformly illuminate the aperture of the antenna mirror.In order to select the structural element of the irradiator several antennas were considered: a patch antenna, a flat spiral antenna, a conical spiral antenna. The requirements for the phased antenna array element were defined. The irradiator based on the above mentioned was simulated and the irradiator geometry was optimized according to the maximum gain criterion.The maximum gain was achieved for the irradiator based on conical spiral antennas and amounted to 30.8 dB, which for the considered mirror aperture of 2.4 m is close to traditional focal schemes. The results obtained make it possible to create an adaptive antenna system able to compensate for the deviations of the mirror's shape from the theoretical profile, as well as phase distortions in the atmosphere by changing the lattice weights coefficients.

Style APA, Harvard, Vancouver, ISO itp.

35

Li, Song, Feixue Wang, Xiaomei Tang, Shaojie Ni i Honglei Lin. "Anti-Jamming GNSS Antenna Array Receiver with Reduced Phase Distortions Using a Robust Phase Compensation Technique". Remote Sensing 15, nr 17 (3.09.2023): 4344. http://dx.doi.org/10.3390/rs15174344.

Pełny tekst źródła

Streszczenie:

Antenna arrays with adaptive filtering can protect the integrity and functionality of global navigation satellite system (GNSS) receivers against interference. However, a major problem with existing adaptive array processing algorithms is that they cause phase distortions and introduce bias errors into the carrier phase measurement, limiting high-precision applications. In this paper, a robust phase compensation technique is proposed to reduce the phase distortion. First, a phase bias detection method is developed to trigger the phase compensation technique. Then, the phase bias is estimated using a robust estimation method and compensated for in the GNSS receiver. The proposed technique operates in real time and causes no processing delay, while requiring only a minor modification to existing GNSS receivers. This technique is applied to the power inversion adaptive antenna, and can also be extended to a wide variety of adaptive antennas. The simulation experiments verify the applicability of the proposed technique and also confirm its superiority over existing techniques.

Style APA, Harvard, Vancouver, ISO itp.

36

Shore, Robert A. "Adaptive Nulling in Hybrid Reflector Antennas". Electromagnetics 15, nr 1 (styczeń 1995): 93–121. http://dx.doi.org/10.1080/02726349508908402.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

37

Baik, J. I., E. H. Lee i H. K. Song. "Adaptive cooperative communications with multiple antennas". Journal of Electromagnetic Waves and Applications 27, nr 13 (5.08.2013): 1632–39. http://dx.doi.org/10.1080/09205071.2013.821677.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

38

Lambert, Jeremy R., Constantine A. Balanis i Dennis DeCarlo. "Spherical Cap Adaptive Antennas for GPS". IEEE Transactions on Antennas and Propagation 57, nr 2 (luty 2009): 406–13. http://dx.doi.org/10.1109/tap.2008.2011219.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

39

Sarkar, T. K., Jinwan Koh, R. Adve, R. A. Schneible, M. C. Wicks, Seungwon Choi i M. Salazar-Palma. "A pragmatic approach to adaptive antennas". IEEE Antennas and Propagation Magazine 42, nr 2 (kwiecień 2000): 39–55. http://dx.doi.org/10.1109/74.842124.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

40

Agrawal, Brij N., i Hyochoong Bang. "Adaptive structures for large precision antennas". Acta Astronautica 38, nr 3 (luty 1996): 175–83. http://dx.doi.org/10.1016/0094-5765(96)00062-8.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

Wang, Jinkuan, i Tadashi Takano. "Adaptive antennas using a kalman filter". Electronics and Communications in Japan (Part I: Communications) 77, nr 2 (luty 1994): 60–70. http://dx.doi.org/10.1002/ecja.4410770206.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

42

Chiba, Isamu, Wataru Chujo i Masayuki Fujise. "Beam-space CMA adaptive array antennas". Electronics and Communications in Japan (Part I: Communications) 78, nr 2 (luty 1995): 85–95. http://dx.doi.org/10.1002/ecja.4410780208.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

43

Fokin, Grigoriy. "Problem Statement for the Developing a New Training Course «5G Smart Antennas Technologies»". Telecom IT 10, nr 3 (23.12.2022): 60–73. http://dx.doi.org/10.31854/2307-1303-2022-10-3-60-73.

Pełny tekst źródła

Streszczenie:

Interest in smart antenna technologies is due to the development of ultra-dense networks of the fifth 5G and subsequent B5G (Beyond 5G) generations of the millimeter-wave band (MMW, millimeter-wave – mmWave), which is confirmed by the high publication activity of recent years both in the native, and in foreign scientific community. Together with scientific publications in foreign literature, textbooks in this area are published and republished. At the same time, in the native scientific and methodological literature, there is currently no textbook that reveals new approaches to studying the issues of adaptive beamforming using smart antennas in relation to ultra-dense 5G and B5G networks. In this paper, an analysis of the state of the problem in the field of intelligent antennas is carried out and a task is formulated for the development of an appropriate training course. Subject of study. The article is devoted to a contemporary review of the state of the problem in the field of smart antennas based on the analysis of Russian sources. Method. Analysis of the evolution of the development of methods and means of smart antenna technologies. Main results. The result of this work is the setting of the task for the development of a new training course "Technologies of smart antennas 5G". Practical significance. The analysis carried out serves as a rationale for the relevance and necessity of developing a new training course "Technologies of smart antennas 5G".

Style APA, Harvard, Vancouver, ISO itp.

44

Subramaniam, Mahendrakumar, Vanitha Krishnan, Chunchu Rambabu, Gokul Chandrasekaran i Neelam Sanjeev Kumar. "Design of NULLMAC Protocol for Mobile Ad Hoc Network Using Adaptive Antenna Array". Mobile Information Systems 2023 (6.04.2023): 1–11. http://dx.doi.org/10.1155/2023/2952410.

Pełny tekst źródła

Streszczenie:

Usually, omnidirectional radiation pattern antenna is used in the mobile ad hoc network (MANET) which causes neighbor node interference, consumes more power, and supports only limited range of transmission. To overcome these problems, smart antennas are used. A lot of medium access control (MAC) protocols are proposed using smart antennas. Existing works addressed various problems such as hidden terminal problem, hidden beam problem, deafness of nodes, and head of line blocking problem. However, certain factors including determination of weight vector and conveying it to the neighbor nodes for distortion-free transmission are not considered. In this study, nullifying MAC (NULLMAC) framework is proposed using an adaptive antenna array (AAA) for improving network performance in MANET. NULLMAC framework uses channel information for achieving high throughput and spatial reuse through integrated physical and MAC layer. Before the transfer of data packets, the receiver initially determines its weight vector and conveys it to the transmitter through control packets. Then, the transmitter computes its weight to nullify the dynamic receivers present in the neighborhood region to find the desired receiver. Beamformer weights are determined through channel coefficients between a transmitter-receiver pair to establish distortion-free transmission. Extensive simulations are performed using OPNET integrated with MATLAB. NULLMAC framework achieves 27.22% more throughput and 40.46% increase in signal-to-noise ratio.

Style APA, Harvard, Vancouver, ISO itp.

45

Zhai, Yan, Xing Wei, Lei Liu i Liao Yuan Wu. "An Improved Ad Hoc Network Communication Based on Cluster". Advanced Materials Research 660 (luty 2013): 184–89. http://dx.doi.org/10.4028/www.scientific.net/amr.660.184.

Pełny tekst źródła

Streszczenie:

In order to tackle the data transmission bottlenecks of the gateway node in clustering Ad hoc Networks, the paper proposes a communication method. Firstly, DMAC (Distributed and Mobility-Adaptive Clustering) algorithm and Omni-directional antenna is well introduced and discussed. Then the ICMMDA (The Inter-cluster Communication Method based on Directional Antennas) policy building virtual channels between two hops away cluster-head and using directional antenna is brought about. Lastly, the simulation shows that the method can reduce the end-to-end delay between two clusters and improve the network throughput.

Style APA, Harvard, Vancouver, ISO itp.

46

Sawant, Vishal V., i Mahesh Chavan. "Performance of Beamforming for Smart Antenna using Traditional LMS Algorithm for Various Parameters". International Journal of Computers and Communications 15 (14.04.2021): 8–13. http://dx.doi.org/10.46300/91013.2021.15.2.

Pełny tekst źródła

Streszczenie:

Adaptive signal processing sensor arrays, known also as smart antennas .The smart antenna adaptive algorithms achieve the best weight vector for beam forming by iterative means. The Least Mean Square (LMS) algorithm, is an adaptive algorithm .LMS incorporates an iterative procedure that makes successive corrections to the weight vector in the direction of the negative of the gradient vector which eventually leads to the minimum mean square error. Beam forming is directly determined by the two factors. The performance of the traditional LMS algorithm for different parameters is analysed in this paper. This algorithm can be applied to beam forming with the software Matlab. The result obtain can achieve faster convergence and lower steady state error. The algorithms can be simulated in MATLAB 7.10 version.

Style APA, Harvard, Vancouver, ISO itp.

47

Blogh, J. S., P. J. Cherriman i L. Hanzo. "Dynamic channel allocation techniques using adaptive modulation and adaptive antennas". IEEE Journal on Selected Areas in Communications 19, nr 2 (2001): 312–21. http://dx.doi.org/10.1109/49.914509.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

48

Samantaray, Barsa, Kunal Kumar Das i Jibendu Sekhar Roy. "Designing Smart Antennas Using Machine Learning Algorithms". Journal of Telecommunications and Information Technology 4 (31.10.2023): 46–52. http://dx.doi.org/10.26636/jtit.2023.4.1329.

Pełny tekst źródła

Streszczenie:

Smart antenna technologies improve spectral efficiency, security, energy efficiency, and overall service quality in cellular networks by utilizing signal processing algorithms that provide radiation beams to users while producing nulls for interferers. In this paper, the performance of such ML solutions as the support vector machine (SVM) algorithm, the artificial neural network (ANN), the ensemble algorithm (EA), and the decision tree (DT) algorithm used for forming the beam of smart antennas are compared. A smart antenna array made up of 10 half-wave dipoles is considered. The ANN method is better than the remaining approaches when it comes to achieving beam and null directions, whereas EA offers better performance in terms of reducing the side lobe level (SLL). The maximum SLL is achieved using EA for all the user directions. The performance of the ANN algorithm in terms of forming the beam of a smart antenna is also compared with that of the variable-step size adaptive algorithm.

Style APA, Harvard, Vancouver, ISO itp.

49

Junejo, Naveed Ur Rehman, Hamada Esmaiel, Haixin Sun, Zeyad A. H. Qasem i Junfeng Wang. "Pilot-Based Adaptive Channel Estimation for Underwater Spatial Modulation Technologies". Symmetry 11, nr 5 (24.05.2019): 711. http://dx.doi.org/10.3390/sym11050711.

Pełny tekst źródła

Streszczenie:

Spatial Modulation Technologies (SMTs) are schemes that reduce inter-carrier interference (ICI), inter-channel interference, inter-antenna synchronization (IAS), and system complexity for multiple-input multiple-output (MIMO) communication systems. Moreover, high spectral and energy efficiency have rendered SMTs attractive to underwater acoustic (UWA) MIMO communication systems. Consequently, this paper focuses on SMTs such as spatial modulation (SM), generalized spatial modulation (GSM), and fully generalized spatial modulation (FGSM) in which one constant number and one multiple number of antennas are active to transmit data symbols in any time interval for underwater acoustic communication (UWAC). In SMTs, the receiver requires perfect channel state information (P-CSI) for accurate data detection. However, it is impractical that the perfect channel knowledge is available at the receiver. Therefore, channel estimation is of critical importance to obtain the CSI. This paper proposes the pilot-based recursive least-square (RLS) adaptive channel estimation method over the underwater time-varying MIMO channel. Furthermore, maximum likelihood (ML) decoder is used to detect the transmitted data and antennas indices from the received signal and the estimated UWA-MIMO channel. The numerical computation of mean square error (MSE) and bit error rate (BER) performance are computed for different SMTs like SM, GSM and FSGM using Monte Carlo iterations. Simulation results demonstrate that the RLS channel estimation method achieves the nearly same BER performance as P-CSI.

Style APA, Harvard, Vancouver, ISO itp.

50

Sámano-Robles, Ramiro, Egons Lavendelis i Eduardo Tovar. "Performance Analysis of MRC Receivers with Adaptive Modulation and Coding in Rayleigh Fading Correlated Channels with Imperfect CSIT". Wireless Communications and Mobile Computing 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/6940368.

Pełny tekst źródła

Streszczenie:

This paper addresses the performance analysis of an adaptive wireless link with one antenna transmitter and a multiple antenna maximum-ratio combining (MRC) receiver. Two main assumptions are used in this paper: (1) Rayleigh fading correlated channels (i.e., MRC branch correlation) and (2) imperfect (outdated) channel state information at the transmitter (CSIT) side. The main contribution of this work lies in the derivation of analytic expressions (in terms of a series expansion) of the statistics of correct packet reception conditional on the decisions made by the transmitter based on outdated CSIT. The novelty of this derivation is the joint modelling of spatially correlated branches, imperfect CSIT, and adaptive modulation based on threshold-trigger decision. Contrary to common belief, the results presented here suggest that spatial correlation not always affects the performance of the MRC receiver: at low signal-to-noise ratio (SNR), correlation can improve performance rather than degrading it. In contrast, at high SNR, correlation is found to always degrade performance. At high SNR, correlation tends to worse the degrading effects of imperfect CSIT, particularly when the number of antennas increases. Imperfect CSIT causes errors in the assignment of MCSs, thus reducing throughput performance. These errors become more evident in the high SNR regime, particularly when the values of branch correlation and the number of antennas increase.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Adaptive antennas”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych