Siga este enlace para ver otros tipos de publicaciones sobre el tema: MIMO systems. Broadband communication systems. Antenna arrays.
Artículos de revistas sobre el tema "MIMO systems. Broadband communication systems. Antenna arrays"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 35 mejores artículos de revistas para su investigación sobre el tema "MIMO systems. Broadband communication systems. Antenna arrays".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Hu, Zhuomin, Wenli Ji, Hengkai Zhao, Xuping Zhai, Asad Saleem y Guoxin Zheng. "Channel Measurement for Multiple Frequency Bands in Subway Tunnel Scenario". International Journal of Antennas and Propagation 2021 (2 de junio de 2021): 1–13. http://dx.doi.org/10.1155/2021/9991758.
Texto completoResumen
In next-generation radio communication systems, the use of higher frequency bands and the massive multiple-input-multiple-output (MIMO) systems has turned into hot research topics because they have the potential to increase network capacity significantly by exploiting the available narrowband and broadband spectrums. Therefore, the narrowband channel measurements are executed at the following five potential frequency bands, including 2.6 GHz, 3.5 GHz, 5.6 GHz, 10 GHz, and 28 GHz in the Shanghai subway tunnel environment in order to fulfill the latest standards of fifth generation (5G). Moreover, in the broadband channel measurements, the center frequency is 3.5 GHz and 5.6 GHz and the bandwidth is considered as 160 MHz, respectively. At the transmitter (Tx) side, a uniform rectangular antenna array composed of 32 elements is fixed on the platform near the tunnel walls. The receiver (Rx) is equipped with a uniform cylindrical antenna array consisting of 64 elements, which is set on a trolley along the track. Based on the acquired massive MIMO channel impulse responses, delay spread, angle spread, eigenvalue and channel capacity are analyzed. The results reveal that the multipath delay in the tunnel scenario is quite short, the delay spread and angle spread drop rapidly as the distance between Tx and Rx increases and the channel matrix gradually becomes serious. This research provides a reference for the deployment of future 5G systems in the subway tunnel.
2
RECIOUI, Abdelmadjid. "Capacity Optimization of MIMO Systems Involving Conformal Antenna Arrays using a Search Group Algorithm". Algerian Journal of Signals and Systems 5, n.º 4 (15 de diciembre de 2020): 209–14. http://dx.doi.org/10.51485/ajss.v5i4.118.
Texto completoResumen
MIMO systems constitute a backbone of the fourth and fifth generations of wireless communication systems. The purpose of this paper is to introduce the involvement of conformal antenna arrays into MIMO systems. The Search Group Algorithm (SGA) is then used to further enhance the capacity of MIMO system employing conformal antenna arrays at both ends (Transmitter; Tx and Receiver; Rx). The results reveal that compared to the linear and 2D cases, conformal antenna arrays promise higher capacity values which motivates their employment in future MIMO communication systems.
3
Lee, Hyunwoo y Byungje Lee. "Compact Broadband Dual-Polarized Antenna for Indoor MIMO Wireless Communication Systems". IEEE Transactions on Antennas and Propagation 64, n.º 2 (febrero de 2016): 766–70. http://dx.doi.org/10.1109/tap.2015.2506201.
Texto completo
4
Fedosov, Valentin, Andrey Legin y Anna Lomakina. "Adaptive algorithm based on antenna arrays for radio communication systems". Serbian Journal of Electrical Engineering 14, n.º 3 (2017): 301–12. http://dx.doi.org/10.2298/sjee1703301f.
Texto completoResumen
Trends in the modern world increasingly lead to the growing popularity of wireless technologies. This is possible due to the rapid development of mobile communications, the Internet gaining high popularity, using wireless networks at enterprises, offices, buildings, etc. It requires advanced network technologies with high throughput capacity to meet the needs of users. To date, a popular destination is the development of spatial signal processing techniques allowing to increase spatial bandwidth of communication channels. The most popular method is spatial coding MIMO to increase data transmission speed which is carried out due to several spatial streams emitted by several antennas. Another advantage of this technology is the bandwidth increase to be achieved without expanding the specified frequency range. Spatial coding methods are even more attractive due to a limited frequency resource. Currently, there is an increasing use of wireless communications (for example, WiFi and WiMAX) in information transmission networks. One of the main problems of evolving wireless systems is the need to increase bandwidth and improve the quality of service (reducing the error probability). Bandwidth can be increased by expanding the bandwidth or increasing the radiated power. Nevertheless, the application of these methods has some drawbacks, due to the requirements of biological protection and electromagnetic compatibility, the increase of power and the expansion of the frequency band is limited. This problem is especially relevant in mobile (cellular) communication systems and wireless networks operating in difficult signal propagation conditions. One of the most effective ways to solve this problem is to use adaptive antenna arrays with weakly correlated antenna elements. Communication systems using such antennas are called MIMO systems (Multiple Input Multiple Output multiple input - multiple outputs). At the moment, existing MIMO-idea implementations do not always noticeably accelerate traffic at short distances from the access point, but, they are very effective at long distances. The MIMO principle allows reducing the number of errors in radio data interchange (BER) without reducing the transmission rate under conditions of multiple signal re-reflections. The work aims at developing an adaptive space-time signal algorithm for a wireless data transmission system designed to improve the efficiency of this system, as well as to study the efficiency of the algorithm to minimizing the error bit probability and maximizing the channel capacity.
5
Ge, Xiaohu, Ran Zi, Haichao Wang, Jing Zhang y Minho Jo. "Multi-User Massive MIMO Communication Systems Based on Irregular Antenna Arrays". IEEE Transactions on Wireless Communications 15, n.º 8 (agosto de 2016): 5287–301. http://dx.doi.org/10.1109/twc.2016.2555911.
Texto completo
6
Tal, Nikolay, Yahav Morag y Yoash Levron. "MAGNETIC INDUCTION ANTENNA ARRAYS FOR MIMO AND MULTIPLE-FREQUENCY COMMUNICATION SYSTEMS". Progress In Electromagnetics Research C 75 (2017): 155–67. http://dx.doi.org/10.2528/pierc17030703.
Texto completo
7
Waldschmidt, C., C. Kuhnert, T. Fügen y W. Wiesbeck. "Realistic antenna modeling for MIMO systems in microcell scenarios". Advances in Radio Science 2 (27 de mayo de 2005): 141–46. http://dx.doi.org/10.5194/ars-2-141-2004.
Texto completoResumen
Abstract. This paper shows the potential of MIMO in cellular systems, where small handheld devices are used for the terminals. A complete model of a MIMO communication link is used to integrate accurate antenna modelling into MIMO system simulations. All different effects of mutual coupling between closely spaced antennas are considered. The efficiency or power budget respectively of the antenna arrays in the terminals, which are influenced by mutual coupling effects, is taken into account. Capacity simulation results based on a channel obtained from ray-tracing simulations are shown with cellular phones with up to three Inverted-F antennas.
8
Lie, D. Y. C., J. C. Mayeda, Y. Li y J. Lopez. "A Review of 5G Power Amplifier Design at cm-Wave and mm-Wave Frequencies". Wireless Communications and Mobile Computing 2018 (4 de julio de 2018): 1–16. http://dx.doi.org/10.1155/2018/6793814.
Texto completoResumen
The 5G wireless revolution presents some dramatic challenges to the design of handsets and communication infrastructures, as 5G targets higher than 10 Gbps download speed using millimeter-wave (mm-Wave) spectrum with multiple-input multiple-output (MIMO) antennas, connecting densely deployed wireless devices for Internet-of-Everything (IoE), and very small latency time for ultrareliable machine type communication, etc. The broadband modulation bandwidth for 5G RF transmitters (i.e., maximum possibly even above 1 GHz) demands high-power efficiency and stringent linearity from its power amplifier (PA). Additionally, the phased-array MIMO antennas with numerous RF front-ends (RFFEs) will require unprecedented high integration level with low cost, making the design of 5G PA one of the most challenging tasks. As the centimeter-wave (cm-Wave) 5G systems will probably be deployed on the market earlier than their mm-Wave counterparts, we will review in this paper the latest development on 15 GHz and 28 GHz 5G cm-Wave PAs extensively, while also covering some key mm-Wave PAs in the literature. Our review will focus on the available options of device technologies, novel circuit and system architectures, and efficiency enhancement techniques at power back-off for 5G PA design.
9
Csathó, Botond Tamás, Bálint Péter Horváth y Péter Horváth. "Modeling the near-field of extremely large aperture arrays in massive MIMO systems". Infocommunications journal 12, n.º 3 (2020): 39–46. http://dx.doi.org/10.36244/icj.2020.3.6.
Texto completoResumen
Massive multiple-input multiple-output (MIMO) is a key technology in modern cellular wireless communication systems to attain a very high system throughput in a dynamic multi-user environment. Massive MIMO relies on deploying base stations equipped with a large number of antenna elements. One possible way to deploy base stations equipped with hundreds or thousands of antennas is creating extremely large aperture arrays. In this paper, we investigate channel modeling aspects of massive MIMO systems with large aperture arrays, in which many users are located in the near-field of the aperture. Oneand two-dimensional antenna geometries, different propagation models, and antenna element patterns are compared in terms of inter-user correlation, condition number of the multi-user channel matrix, and spectral efficiency to identify key design parameters and essential modeling assumptions. As our analysis reveals by choosing spectral-efficiency as a design objective, the size of the aperture is the critical design parameter.
10
Liu, Zuo Xue, Jian Mei Dai y Bo Liu. "The Design of Wireless Broadband Communication System Based on OFDMA". Applied Mechanics and Materials 241-244 (diciembre de 2012): 2275–78. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.2275.
Texto completoResumen
A Wireless Broadband Communication System has been made up based on OFDMA and AMC technologies. The system structure and working pattern is introduced, the OFDMA allocation model, the MIMO and AMC scheme are present, and the parameter such as transmitting power, receiver sensitivity, transmitting antenna gain and receiving antenna gain are designed. The system enables high quality wireless broadband communication. As a supplement with wired communication systems, the system could fulfill the requirement of recovery local communication rapidly when some accidents take place.
11
Zahra, Hijab, Wahaj Abbas Awan, Wael Abd Ellatif Ali, Niamat Hussain, Syed Muzahir Abbas y Subhas Mukhopadhyay. "A 28 GHz Broadband Helical Inspired End-Fire Antenna and Its MIMO Configuration for 5G Pattern Diversity Applications". Electronics 10, n.º 4 (7 de febrero de 2021): 405. http://dx.doi.org/10.3390/electronics10040405.
Texto completoResumen
In this paper, an end-fire antenna for 28 GHz broadband communications is proposed with its multiple-input-multiple-output (MIMO) configuration for pattern diversity applications in 5G communication systems and the Internet of Things (IoT). The antenna comprises a simple geometrical structure inspired by a conventional planar helical antenna without utilizing any vias. The presented antenna is printed on both sides of a very thin high-frequency substrate (Rogers RO4003, εr = 3.38) with a thickness of 0.203 mm. Moreover, its MIMO configuration is characterized by reasonable gain, high isolation, good envelope correlation coefficient, broad bandwidth, and high diversity gain. To verify the performance of the proposed antenna, it was fabricated and verified by experimental measurements. Notably, the antenna offers a wide −10 dB measured impedance ranging from 26.25 GHz to 30.14 GHz, covering the frequency band allocated for 5G communication systems with a measured peak gain of 5.83 dB. Furthermore, a performance comparison with the state-of-the-art mm-wave end-fire antennas in terms of operational bandwidth, electrical size, and various MIMO performance parameters shows the worth of the proposed work.
12
Lonkeng, Alban Doumtsop y Jie Zhuang. "Two-Dimensional DOA Estimation Using Arbitrary Arrays for Massive MIMO Systems". International Journal of Antennas and Propagation 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/6794920.
Texto completoResumen
With the quick advancement of wireless communication networks, the need for massive multiple-input-multiple-output (MIMO) to offer adequate network capacity has turned out to be apparent. As a portion of array signal processing, direction-of-arrival (DOA) estimation is of indispensable significance to acquire directional data of sources and to empower the 3D beamforming. In this paper, the performance of DOA estimation for massive MIMO systems is analyzed and compared using a low-complexity algorithm. To be exact, the 2D Fourier domain line search (FDLS) MUSIC algorithm is studied to mutually estimate elevation and azimuth angle, and arbitrary array geometry is utilized to represent massive MIMO systems. To avoid the computational burden in estimating the data covariance matrix and its eigenvalue decomposition (EVD) due to the large-scale sensors involved in massive MIMO systems, the reduced-dimension data matrix is applied on the signals received by the array. The performance is examined and contrasted with the 2D MUSIC algorithm for different types of antenna configuration. Finally, the array resolution is selected to investigate the performance of elevation and azimuth estimation. The effectiveness and advantage of the proposed technique have been proven by detailed simulations for different types of MIMO array configuration.
13
Cha, Junghoon, Choon-Seong Leem, Ikhwan Kim, Hakyoung Lee y Hojun Lee. "Broadband Dual-Polarized 2 × 2 MIMO Antenna for a 5G Wireless Communication System". Electronics 10, n.º 17 (2 de septiembre de 2021): 2141. http://dx.doi.org/10.3390/electronics10172141.
Texto completoResumen
In this study, we proposed an indoor broadband dual-polarized 2 × 2 MIMO (multiple-input and multiple-output) antenna having dimensions of 240 mm × 200 mm × 40 mm, for application in 5G wireless communication systems. The proposed antenna comprised two vertically polarized circular monopole antennas (CMAs), two horizontally polarized modified rectangular dipole antennas (MRDAs), and a ground plane. The distance between the two MRDAs (MRDA1 and MRDA2) was 70.5 mm and 109.5 mm in the horizontal (x-direction) and 109.5 mm vertical (y-direction) directions, respectively. Conversely, the distance between the two CMAs (CMA1 and CMA2) was 109.5 mm and 70.5 mm in the horizontal (x-direction) and vertical (y-direction) directions, respectively. While the CMAs achieved broadband characteristics owing to the optimal gap between the dielectric and the driven radiator using a parasitic element, the MRDAs achieved broadband owing to the optimal distance between the dipole antennas. The observations in this experiment confirmed that the proposed could operate in the 5G NR n46 (5.15–5.925 GHz), n47 (5.855–5.925 GHz), n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), and the n79 (4.4–5 GHz) bands. Moreover, it exhibited a wide impedance bandwidth (dB magnitude of S11) of 101% in the 2.3–7 GHz frequency range, high isolation (dB magnitude of S21), low envelope coefficient correlation (ECC), gain of over 5 dB, and average radiation efficiency of 87.19%, which verified its suitability for application in sub-6 GHz 5G wireless communication systems.
14
Pavia, João Pedro, Vasco Velez, Renato Ferreira, Nuno Souto, Marco Ribeiro, João Silva y Rui Dinis. "Low Complexity Hybrid Precoding Designs for Multiuser mmWave/THz Ultra Massive MIMO Systems". Sensors 21, n.º 18 (9 de septiembre de 2021): 6054. http://dx.doi.org/10.3390/s21186054.
Texto completoResumen
Millimeter-wave and terahertz technologies have been attracting attention from the wireless research community since they can offer large underutilized bandwidths which can enable the support of ultra-high-speed connections in future wireless communication systems. While the high signal attenuation occurring at these frequencies requires the adoption of very large (or the so-called ultra-massive) antenna arrays, in order to accomplish low complexity and low power consumption, hybrid analog/digital designs must be adopted. In this paper we present a hybrid design algorithm suitable for both mmWave and THz multiuser multiple-input multiple-output (MIMO) systems, which comprises separate computation steps for the digital precoder, analog precoder and multiuser interference mitigation. The design can also incorporate different analog architectures such as phase shifters, switches and inverters, antenna selection and so on. Furthermore, it is also applicable for different structures, namely fully-connected structures, arrays of subarrays (AoSA) and dynamic arrays of subarrays (DAoSA), making it suitable for the support of ultra-massive MIMO (UM-MIMO) in severely hardware constrained THz systems. We will show that, by using the proposed approach, it is possible to achieve good trade-offs between spectral efficiency and simplified implementation, even as the number of users and data streams increases.
15
Alemaishat, Saraereh, Khan, Affes, Li y Lee. "An Efficient Precoding Scheme for Millimeter-Wave Massive MIMO Systems". Electronics 8, n.º 9 (24 de agosto de 2019): 927. http://dx.doi.org/10.3390/electronics8090927.
Texto completoResumen
Aiming at the problem of high computational complexity due to a large number of antennas deployed in mmWave massive multiple-input multiple-output (MIMO) communication systems, this paper proposes an efficient algorithm for optimizing beam control vectors with low computational complexity based on codebooks for millimeter-wave massive MIMO systems with split sub-arrays hybrid beamforming architecture. A bidirectional method is adopted on the beam control vector of each antenna sub-array both at the transmitter and receiver, which utilizes the idea of interference alignment (IA) and alternating optimization. The simulation results show that the proposed algorithm has low computational complexity, fast convergence, and improved spectral efficiency as compared with the state-of-the-art algorithms.
16
Song, Rongguo, Xiaoxiao Chen, Shaoqiu Jiang, Zelong Hu, Tianye Liu, David G. Calatayud, Boyang Mao y Daping He. "A Graphene-Assembled Film Based MIMO Antenna Array with High Isolation for 5G Wireless Communication". Applied Sciences 11, n.º 5 (8 de marzo de 2021): 2382. http://dx.doi.org/10.3390/app11052382.
Texto completoResumen
With the development of 5G, Internet of Things, and smart home technologies, miniaturized and compact multi-antenna systems and multiple-input multiple-output (MIMO) antenna arrays have attracted increasing attention. Reducing the coupling between antenna elements is essential to improving the performance of such MIMO antenna system. In this work, we proposed a graphene-assembled, as an alternative material rather than metal, film-based MIMO antenna array with high isolation for 5G application. The isolation of the antenna element is improved by a graphene assembly film (GAF) frequency selective surface and isolation strip. It is shown that the GAF antenna element operated at 3.5 GHz has the realized gain of 2.87 dBi. The addition of the decoupling structure improves the isolation of the MIMO antenna array to more than 10 dB and corrects the antenna radiation pattern and operating frequency. The isolation between antenna elements with an interval of 0.4λ is above 25 dB. All experimental results show that the GAF antenna and decoupling structure are efficient devices for 5G mobile communication.
17
Moussa, Karim H., Ahmed S. I. Amar, Mohamed Mabrouk y Heba G. Mohamed. "Slotted E-Shaped Meta-Material Decoupling Slab for Densely Packed MIMO Antenna Arrays". Micromachines 12, n.º 8 (25 de julio de 2021): 873. http://dx.doi.org/10.3390/mi12080873.
Texto completoResumen
In contemporary wireless communication systems, the multiple-input and multiple-output systems are extensively utilized due to their enhanced spectral efficiency and diversity. Densely packed antenna arrays play an important role in such systems to enhance their spatial diversity, array gain, and beam scanning capabilities. In this article, a slotted meta-material decoupling slab (S-MTM-DS) with dual reflexes slotted E-shapes and an inductive stub is proposed. Its function was validated when located between two microstrip patch antenna elements to reduce the inter-element spacing, the mutual coupling, the return losses, and manufacturing costs due to size reduction. A prototype is simply fabricated in a volume of 67.41 × 33.49 × 1.6 mm3 and frequency-span measured from 8.4:11 GHz. At 9.4 GHz frequency, the spaces between the transmitting elements are decreased to 0.57 of the free space wavelength. When the proposed isolation S-MTM-DS is applied, the average isolation among them is measured to be −36 dB, the operational bandwidth is enhanced to be 1.512 GHz, the fractional bandwidth improved to be 16.04%, and the return losses are decreased to be −26.5 dB at 9.4 GHz center frequency. Consequently, the proposed design has the potential to be implemented simply in wireless contemporary communication schemes.
18
Zhao, Renjie, Timothy Woodford, Teng Wei, Kun Qian y Xinyu Zhang. "M-CUBE". GetMobile: Mobile Computing and Communications 25, n.º 1 (15 de junio de 2021): 30–33. http://dx.doi.org/10.1145/3471440.3471449.
Texto completoResumen
Millimeter-wave (mmWave) technologies represent a cornerstone for emerging wireless network infrastructure, and for RF sensing systems in security, health, and automotive domains. However, the lack of an experimental platform has been impeding research in this field. In this article, we propose to fill the gap with M3 (M-Cube), the first mmWave massive MIMO software radio. M3 features a fully reconfigurable array of phased arrays, with up to 8 RF chains and 256 antenna elements. Despite the orders of magnitude larger antenna arrays, its cost is orders of magnitude lower, even when compared with state-of-the-art single RF chain mmWave software radios. Case studies have demonstrated the usefulness of M3 design for research in mmWave massive MIMO communication and sensing.
19
Alibakhshikenari, Mohammad, Bal Virdee, Panchamkumar Shukla, Chan See, Raed Abd-Alhameed, Mohsen Khalily, Francisco Falcone y Ernesto Limiti. "Antenna Mutual Coupling Suppression Over Wideband Using Embedded Periphery Slot for Antenna Arrays". Electronics 7, n.º 9 (16 de septiembre de 2018): 198. http://dx.doi.org/10.3390/electronics7090198.
Texto completoResumen
This paper presents a new approach to suppress interference between neighbouring radiating elements resulting from surface wave currents. The proposed technique will enable the realization of low-profile implementation of highly dense antenna configuration necessary in SAR and MIMO communication systems. Unlike other conventional techniques of mutual coupling suppression where a decoupling slab is located between the radiating antennas the proposed technique is simpler and only requires embedding linear slots near the periphery of the patch. Attributes of this technique are (i) significant improvement in the maximum isolation between the adjacent antennas by 26.7 dB in X-band and >15 dB in Ku and K-bands; (ii) reduction in edge-to-edge gap between antennas to 10 mm (0.37 λ); and (iii) improvement in gain by >40% over certain angular directions, which varies between 4.5 dBi and 8.2 dBi. The proposed technique is simple to implement at low cost.
20
Farahat, Asmaa y Khlaid Hussein. "Dual-band (28/38 GHz) MIMO Antenna System for 5G Mobile Communications with Efficient DoA Estimation Algorithm in Noisy Channels". Applied Computational Electromagnetics Society 36, n.º 3 (20 de abril de 2021): 282–94. http://dx.doi.org/10.47037/2020.aces.j.360308.
Texto completoResumen
In this paper, a dual-band (28/38 GHz) linear antenna arrays of four and eight elements are proposed to work as a MIMO arrays for the 5G communication systems. Each element in the array is a dual-band Yagi-Uda antenna designed to operate at 28 and 38 GHz. The eight-elements array size has a total dimension of 79.4 mm x 9.65 mm excluding the feeding microstrip line. The maximum gain of the array is about 18 dB. The peaks of correlation at matched angles (PCMA) technique is applied to determine the direction of arrival for multiple incoming signals. The effects of phase noise and additive Gaussian noise on the error in the DoA estimation are studied showing good accuracy of the PCMA algorithm. Numerical and experimental investigations are achieved to assess the performance of both the single-element antenna and the eight-element MIMO linear antenna array. It is shown that the simulation results agree with the experimental measurements and both show good performance of the single antenna as well as the MIMO linear array system. The envelope correlation coefficient (ECC) and the diversity gain (DG) are calculated and the results show that the proposed MIMO antenna system is suitable for the forthcoming 5G mobile communications. The radiation patterns for single antenna and four-element array are measured and compared to the electromagnetic simulation results showing good agreement.
21
Khan, Ejaz y Conor Heneghan. "Capacity of fully correlated MIMO system using character expansion of groups". International Journal of Mathematics and Mathematical Sciences 2005, n.º 15 (2005): 2461–71. http://dx.doi.org/10.1155/ijmms.2005.2461.
Texto completoResumen
It is well known that the use of antenna arrays at both sides of communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. In this work, the capacity of MIMO systems under fully correlated (i.e., correlations between rows and columns of channel matrix) fading is considered. We use replica method and character expansions to calculate the capacity of correlated MIMO channel in closed form. In our calculations, it is assumed that the receiver has perfect channel state information (CSI) but no such information is available at the transmitter.
22
Yang, Jiyeong, Wonjae Ryoo, Wonjin Sung, Jeong-Ho Kim y Jonghyun Park. "3D Antenna Structures Using Uniform Triangular Arrays for Efficient Full-Directional Multiuser Transmission". International Journal of Antennas and Propagation 2019 (5 de noviembre de 2019): 1–12. http://dx.doi.org/10.1155/2019/4150378.
Texto completoResumen
In order to increase the system capacity of the 5G mobile communication system, multiple-input multiple-output (MIMO) transmission techniques using a large-scale array over the millimeter-wave band have attracted a great amount of attention. To cope with various types of receivers expected in 5G communications such as user equipment (UE) in small cells, indoor Internet-of-Things (IoT) devices at diverse locations, and drones performing aerial navigation, newer types of antenna arrays require all-directional transmission capability. Existing antenna structures with typical panel arrays, however, have restrictions on their transmission angles in both horizontal and vertical directions. In this paper, we propose to employ three-dimensional (3D) array structures composed of multiple triangular panels for efficient massive MIMO transmission of the next-generation wireless systems. We analyze beamforming characteristics of a uniform triangular array (UTA) suitable for such 3D array configurations and present a basic codebook applicable to UTAs. Using antenna structures with multiple UTA panels, multiuser transmission performance is evaluated to demonstrate the effectiveness of the proposal.
23
Asif, Rao Muhammad, Jehangir Arshad, Mustafa Shakir, Sohail M. Noman y Ateeq Ur Rehman. "Energy Efficiency Augmentation in Massive MIMO Systems through Linear Precoding Schemes and Power Consumption Modeling". Wireless Communications and Mobile Computing 2020 (17 de septiembre de 2020): 1–13. http://dx.doi.org/10.1155/2020/8839088.
Texto completoResumen
Massive multiple-input multiple-output or massive MIMO system has great potential for 5th generation (5G) wireless communication systems as it is capable of providing game-changing enhancements in area throughput and energy efficiency (EE). This work proposes a realistic and practically implementable EE model for massive MIMO systems while a general and canonical system model is used for single-cell scenario. Linear processing schemes are used for detection and precoding, i.e., minimum mean squared error (MMSE), zero-forcing (ZF), and maximum ratio transmission (MRT/MRC). Moreover, a power dissipation model is proposed that considers overall power consumption in uplink and downlink communications. The proposed model includes the total power consumed by power amplifier and circuit components at the base station (BS) and single antenna user equipment (UE). An optimal number of BS antennas to serve total UEs and the overall transmitted power are also computed. The simulation results confirm considerable improvements in the gain of area throughput and EE, and it also shows that the optimum area throughput and EE can be realized wherein a larger number of antenna arrays at BS are installed for serving a greater number of UEs.
24
Dilli, Ravilla. "Performance analysis of multi user massive MIMO hybrid beamforming systems at millimeter wave frequency bands". Wireless Networks 27, n.º 3 (4 de febrero de 2021): 1925–39. http://dx.doi.org/10.1007/s11276-021-02546-w.
Texto completoResumen
AbstractMillimeter-wave (mmWave) and massive multi-input–multi-output (mMIMO) communications are the most key enabling technologies for next generation wireless networks to have large available spectrum and throughput. mMIMO is a promising technique for increasing the spectral efficiency of wireless networks, by deploying large antenna arrays at the base station (BS) and perform coherent transceiver processing. Implementation of mMIMO systems at mmWave frequencies resolve the issue of high path-loss by providing higher antenna gains. The motivation for this research work is that mmWave and mMIMO operations will be much more popular in 5G NR, considering the wide deployment of mMIMO in major frequency bands as per 3rd generation partnership project. In this paper, a downlink multi-user mMIMO (MU-mMIMO) hybrid beamforming communication system is designed with multiple independent data streams per user and accurate channel state information. It emphasizes the hybrid precoding at transmitter and combining at receiver of a mmWave MU-mMIMO hybrid beamforming system. Results of this research work give the tradeoff between multiple data streams per user and required number of BS antennas. It strongly recommends for higher number of parallel data streams per user in a mmWave MU-mMIMO systems to achieve higher order throughputs.
25
Wang, Hengfeng, Chao Liu, Huaning Wu, Bin Li y Xu Xie. "Optimal Pattern Synthesis of Linear Array and Broadband Design of Whip Antenna Using Grasshopper Optimization Algorithm". International Journal of Antennas and Propagation 2020 (20 de enero de 2020): 1–14. http://dx.doi.org/10.1155/2020/5904018.
Texto completoResumen
Antenna arrays with high directivity, low side-lobe level, and null control in desired direction and whip antenna with wider bandwidth both need to be optimized to meet different needs of communication systems. A new natural heuristic algorithm simulating social behavior of grasshoppers, grasshopper optimization algorithm (GOA), is applied to electromagnetic field as a new effective technology to solve the antenna optimization problem for the first time. Its algorithm is simple and has no gradient mechanism, can effectively avoid falling into local optimum, and is suitable for single-objective and multiobjective optimization problems. GOA is used to optimize the side lobe suppression, null depth, and notch control of arbitrary linear array and then used to optimize the loading and matching network of 10-meter HF broadband whip antenna compared with other algorithms. The results show that GOA has more advantages in side-lobe suppression, null depth, and notch control of linear array than other algorithms and has better broadband optimization performance for HF whip antenna. The pattern synthesis and antenna broadband optimization based on GOA provide a new and effective method for antenna performance optimization.
26
Kirov, Georgi, Georgi Chervenkov y Chavdar Kalchev. "Aperture Coupled Microstrip Short Backfire Antenna". Journal of Electrical Engineering 63, n.º 2 (1 de marzo de 2012): 75–80. http://dx.doi.org/10.2478/v10187-012-0011-0.
Texto completoResumen
Aperture Coupled Microstrip Short Backfire Antenna A broadband aperture coupled microstrip short backfire antenna is described herein. It consists of a feed part (a microstrip feed line and a coupling slot in a metal ground) and a radiating part with two radiators: a patch antenna and a backfire antenna. The bandwidth widening of the antenna is achieved by use of two resonances: a patch resonance and a backfire resonance. The antenna is designed to operate within the Ku-band. It has a frequency bandwidth of about 15% and a maximum gain of 11.5 dBi. Within the antenna bandwidth the gain and the radiation efficiency have values more than 9 dBi and 82.1%, respectively. The designed antenna has a simple and compact construction and high mechanical and electrical characteristics. It can be used as a single antenna or as an element of microstrip antenna arrays with various applications in the contemporary communication systems.
27
Wei, Yiqiao, Shuzhi Liu y Seung-Hoon Hwang. "Distance Protection for Coexistence of 5G Base Station and Satellite Earth Station". Electronics 10, n.º 12 (19 de junio de 2021): 1481. http://dx.doi.org/10.3390/electronics10121481.
Texto completoResumen
In this paper, we investigate the coexistence of the 5G communication network with a fixed-satellite service (FSS) in the 3.5 GHz and 26 GHz frequency bands. We analyze a distance protection scheme for the FSS Earth station (ES) and 5G base stations (BS). Furthermore, we define the exclusion and restriction zones to develop a transmit power control scheme based on the Citizens Broadband Radio Service (CBRS). An interactive power control scheme is also devised for the restriction zone and extensively analyzed through simulations. The proposed scheme is examined for practical scenarios such as the rural macrocells (RMa), urban macrocells (UMa), and urban microcells (UMi) as defined by the 3GPP. The impact of the antenna type is also investigated, and BSs with omnidirectional, 4 × 4, 8 × 8, and 16 × 16 antenna arrays are examined, as defined by 3GPP, for the 5G networks. The results confirm that 5G systems can coexist with the FSS and provide quantitative insights into the selection of the system parameters, including interference margins, exclusion sizes, and reduction zones, for different scenarios and antenna types.
28
Vidal-Beltrán, Sergio y José Luis López-Bonilla. "Improving Spectral Efficiency in the SCMA Uplink Channel". Mathematics 9, n.º 6 (18 de marzo de 2021): 651. http://dx.doi.org/10.3390/math9060651.
Texto completoResumen
The Third Generation Partnership Project (3GPP) and the International Telecommunication Union (ITU) identified the technical requirements that the fifth generation of mobile communications networks (5G) had to meet; within these parameters are the following: an improved data rate and a greater number of users connected simultaneously. 5G uses non-orthogonal multiple access (NOMA) to increase the number of simultaneously connected users, and by encoding data it is possible to increase the spectral efficiency (SE). In this work, eight codewords are used to transmit three bits simultaneously using Sparse Code Multiple Access (SCMA), and through singular value decomposition (SVD) the Euclidean distance between constellation points is optimized. On the other hand, applications of machine intelligence and machine intelligence in 5G and beyond communication systems are still developing; in this sense, in this work we propose to use machine learning for detecting and decoding the SCMA codewords using neural networks. This paper focuses on the Use Case of enhanced mobile broadband (eMBB), where higher data rates are required, with a large number of users connected and low mobility. The simulation results show that it is possible to transmit three bits simultaneously with a low bit error rate (BER) using SVD-SCMA in the uplink channel. Our simulation results were compared against recent methods that use spatial modulation (SM) and antenna arrays in order to increase spectral efficiency. In adverse Signal-to-Noise Ratio (SNR), our proposal performs better than SM, and antenna arrays are not needed for transmission or reception.
29
"Performance Evaluation of Mimo System with Massive Antenna Arrays". VOLUME-8 ISSUE-10, AUGUST 2019, REGULAR ISSUE 8, n.º 10 (10 de agosto de 2019): 981–84. http://dx.doi.org/10.35940/ijitee.j9135.0881019.
Texto completoResumen
In the ground of digital word, wireless communication system has widespread functions. The demand for wireless communication is growing day by day. All users want better quality service in scope of wireless communication. Due to high bit error rate (BER), low signal to noise ratio (SNR), limited bandwidth and high standard deviation (SD) of phase error conventional wireless communiqué systems like SISO, SIMO and MISO flops to gather the mounting demand of users. Therefore a new technique MIMO system is realized whose performance is evaluated by parameters BER, SNR and SD of Phase Error. Latest approach for increasing the performance of virtual MIMO communications within peers by ill-treatment situation with giant antenna arrays is developed. MIMO provides low BER and low SD of Phase Error with increased SNR, which forms a good feature for wireless communication system. In this paper, performance of MIMO is assessed under Nakagami-m and Rayleigh fading channels. For a wireless system BER and SD of phase error should be minimum, which is achieved in MIMO system.
30
PATEL, NIRAV D., VIJAY K. PATEL y DHARMESH SHAH. "INVESTIGATION OF CAPACITY GAINS IN MIMO CORRELATED RICIAN FADING CHANNELS SYSTEMS". International Journal of Electronics Signals and Systems, octubre de 2013, 76–83. http://dx.doi.org/10.47893/ijess.2013.1143.
Texto completoResumen
This paper investigate the effect of Rician fading and correlation on the capacity and diversity of MIMO channels. The use of antenna arrays at both sides of the wireless communication link (MIMO systems) can increase channel capacity provided the propagation medium is rich scattering or Rayleigh fading and the antenna arrays at both sides are uncorrelated. However, the presence of line-of-sight (LOS) component and correlation of real world wireless channels may affect the system performance. Along with that we also investigate power distribution methods for higher capacity gains and effect of CSI at the transmitter on the capacity for range of SNR. Our investigation follows capacity gain as function of number of antennas and signal-to-noise (SNR) power ratio Block and frequency nonselective Rician fading channel is assumed, and the effect of Rician factor (L) and the correlation parameter (ρ) on the capacity and diversity gains of MIMO channels are found. Index.
31
Popov, Valentin, Vladimir Skudnov y Alexey Vasilyev. "ANTENNAS OF MOBILE TERMINALS IN MODERN MOBILE COMMUNICATION NETWORKS (OVERVIEW)". Visnyk Universytetu “Ukraina”, 2019. http://dx.doi.org/10.36994/2707-4110-2019-1-22-04.
Texto completoResumen
In connection with the development of technology of mobile terminals (cell phones, smartphones, tablets, computers with wireless modems, etc.) in the standards of UMTS (3G) and LTE (4G) great attention of manufacturers of these devices is concentrating on the modernization and development of antenna systems of mobile stations (terminals). Currently, antenna systems of mobile stations is implementing on base of technology in form of complex configuration microstrip transmission lines, which ensure compliance with the requirements of modern wireless communication standards. Adaptive antenna arrays and MIMO antenna systems are implemented in mobile terminals for road and railway transport, which allow to achieve a sustainable reception of signals from the base stations. As you know, the difficult conditions for the propagation of radio waves in cellular mobile communication systems are associated with their absorption, multiple reflection and scattering. In these cases, the laws that are true for the line of sight conditions (LOS, Line of Sight) no longer work. The properties of antennas integrated into mobile terminals (mobile stations - MS (Mobile Station)) directly depend on the statistical characteristics of the environment and the location of the operating terminal relative to the spatial position of the user. Therefore, when designing MS antennas in UMTS and LTE mobile communication systems in the frequency ranges from 450 to 3700 MHz, it is important to consider all of the above factors.
32
Shamganth, K. y M. P. Reena. "Capacity Enhancement in WLAN using MIMO". International Journal of Computer and Communication Technology, abril de 2011, 101–6. http://dx.doi.org/10.47893/ijcct.2011.1079.
Texto completoResumen
Increasing demand for high-performance 4G broadband wireless is enabled by the use of multiple antennas at both transmitter and receiver ends. Multiple antenna technologies enable high capacities suited for Internet and multimedia services, and also dramatically increase range and reliability. The combination of multiple-input multiple-output (MIMO) signal processing with orthogonal frequency division multiplexing (OFDM) is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems operating in frequencyselective fading environments. In this paper ,we focus mainly on Internet users in hotspots like Airport etc., requiring high data rate services. A high data rate WLAN system design is proposed using MIMO-OFDM. In the proposed WLAN system, IEEE 802.11a standard design is adopted but the results prove a data rate enhancement from the conventional IEEE 802.11a.
33
"Performance Improvement in MIMO-OFDM Systems based on adaptive Whale Elephant Herd Optimization algorithm". International Journal of Engineering and Advanced Technology 9, n.º 1 (30 de octubre de 2019): 6651–57. http://dx.doi.org/10.35940/ijeat.a1916.109119.
Texto completoResumen
Multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) is the leading air interface for 4G and 5G broadband wireless communications. Cognitive Radio (CR) is the trending technology, which facilitates spectrum sensing to determine the inadequate bands in the spectrum. Though there are so many spectrum sensing techniques, the existing methods suffered a lot in the communication environment. In the traditional CR network, data transmission is constrained to the secondary user within the available bands. With the aim to increase spectrum efficiency and throughput, this paper proposed the hybrid mixture model using Adaptive Whale Elephant Herd Optimization (Adaptive WEHO) algorithm for spectrum sensing. Adaptive WEHO is the integration of Elephant-Herd Optimization (EHO), and Whale Optimization Algorithm (WOA), with the adaptive concept. The signal received from the OFDM antenna is used to analyze the availability of spectrum based on the signal energy and Eigen statistics. The CR searches the availability of channel and makes the connection when it determines a free channel. Here, the spectrum sensing is achieved by the Gaussian Mixture Model (GMM), which is trained by the proposed Adaptive WEHO algorithm. The proposed Adaptive WEHO algorithm uses the foraging behavior of whales and the herding behavior of elephants, which is applied in the spectrum sensing technique to perform the optimal sensing. The proposed Adaptive WEHO attained better performance with the metrics of probability of detection as 1.0238, and the probability of false alarm as 0.01075, respectively. The proposed method ensures the effective communication in CR without any interference.
34
"Hybrid Precoding Design Using MMSE Baseband Precoder for mm-Wave Multi-User MIMO Systems". International Journal of Recent Technology and Engineering 8, n.º 2S11 (2 de noviembre de 2019): 3486–90. http://dx.doi.org/10.35940/ijrte.b1588.0982s1119.
Texto completoResumen
For future 5G wireless communication networks, millimeter-wave (mmWave) cellular systems is considered to be the key enabling technology because of its high data rates, low latency, high system capacity, and huge available bandwidths. However, multiuser networks in mmWave frequency bands encounter high path loss and interference, thus degrading the performance. Applying large antenna arrays at the base stations (BS) in order to achieve high beamforming gains with the help of precoding techniques is an efficient way of improving the performance of the system. Although multi-user beamforming can improve spectral efficiencies, full digital beamforming strategies used in the conventional microwave systems increase the hardware cost and consumes high power for large number of antennas in mmW systems. In this paper, a low-complexity multi-user hybrid precoding structure is proposed for mmWave multiple input multiple output (MIMO) channels utilizing Minimum Mean Square Error (MMSE) precoders at the BS with perfect channel knowledge. Simulations show that the achievable rate obtained by the proposed hybrid precoding scheme is very close to the single-user rate and also performs better compared to other hybrid precoding approaches.
35
"Performance of BER with Different Diversity Techniques for Millimeter-Wave Communication System". International Journal of Innovative Technology and Exploring Engineering 8, n.º 6S4 (26 de julio de 2019): 1149–52. http://dx.doi.org/10.35940/ijitee.f1238.0486s419.
Texto completoResumen
In a communications system, a diversity technique is used to enhance the reliability of a message signal by using at least two channels with different characteristics. In this paper, all four possible scenarios are considered: Single-input and singleoutput (SISO), single input and multi-output (SIMO), multipleinput and single-output (MISO), Multiple-input and multiple output (MIMO) systems. Antenna arrays will be used to reduce BER and improve the performance of the system using array gain in the line of sight channel for 60 GHz frequency in an indoor scenario. Single input and single output are investigated before analysis of multiple inputs and multiple output channel in the line of sight (LOS) and multipath propagation. MATLAB simulation has been performed using BPSK modulation. The comparative studies show that the performance of the MIMO diversity technique is more reliable in terms of BER to improve the performance and efficiency of the communication system.