scholarly journals Two approaches to multiuser detection over fading channels

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 11-20
Author(s):  
V. P. Tuzlukov
Keyword(s):  
Antenna Array ◽  
Fading Channels ◽  
Multiuser Detection ◽  
Antenna Arrays ◽  
Additive White Gaussian Noise ◽  
Antenna Element ◽  
Blind Adaptive ◽  
Receiving Antenna ◽  
Downlink Channels ◽  
Code Division Multiple

In this paper, two different receiver structures to multiuser detection that are appropriate for the code-division multiple-access systems with antenna arrays in fading channels are investigated and compared. We analyze and compare the performance of the two different multiuser detection structures for uplink or downlink channels. The number of elements of receiving antenna array may be limited in the downlink channel due to the small size of receivers. We assume a synchronous system, but it can be easily extended to an asynchronous system. The first approach is based on the distributed decorrelator where the signal decorrelation is performed by each receiving antenna element independently and decorrelated outputs are combined according to the maximum ratio. The second approach is the central decorrelator where the signal decorrelation is performed once collectively on the outputs from all elements of receiving antenna array. Both decorrelators provide the same performance in the additive white Gaussian noise channels. The distributed decorrelator provides the better performance in flat fading channels. We employ the decorrelator to demonstrate our results. The results discussed in the present paper can be extended to other configurations such as the blind adaptive space-time multiuser detection.

scholarly journals A Graphene-Assembled Film Based MIMO Antenna Array with High Isolation for 5G Wireless Communication

2021 ◽  
Vol 11 (5) ◽  
pp. 2382
Author(s):  
Rongguo Song ◽  
Xiaoxiao Chen ◽  
Shaoqiu Jiang ◽  
Zelong Hu ◽  
Tianye Liu ◽  
...  
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Multiple Input Multiple Output ◽  
Frequency Selective Surface ◽  
Antenna System ◽  
Antenna Element ◽  
Mimo Antenna ◽  
High Isolation ◽  
Input Multiple Output ◽  
Alternative Material

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.

scholarly journals Single-element based ultra-wideband antenna array concepts for wireless high-precision 2-D local positioning

2013 ◽  
Vol 11 ◽  
pp. 297-305 ◽  
Author(s):  
M. Gardill ◽  
G. Fischer ◽  
R. Weigel ◽  
A. Koelpin
Keyword(s):  
Antenna Array ◽  
High Precision ◽  
Antenna Arrays ◽  
Ultra Wideband ◽  
Antenna Element ◽  
Single Element ◽  
Angle Of Arrival ◽  
Wideband Antenna ◽  
Local Positioning System ◽  
5 Ghz

Abstract. We generally categorize the approaches for ultra-wideband antenna array design, and consequently propose simplified concepts for antenna arrays for a high-precision, ultra-wideband FMCW radar 2-D local positioning system to obtain robustness against multi path interference, perform angle of arrival analysis, as well as instantaneous heading estimation. We focus on low-cost and mechanical robust, industrial-application ready antennas. The antenna arrays are optimized for operation in the 5 GHz to 8 GHz frequency range and are designed towards supporting full omnidirectional 360° as well as partial half-plane direction of arrival estimation. Two different concepts for vehicle- as well as wall-mounted antenna array systems are proposed and discussed. We propose a wideband unidirectional bow-tie antenna array element having 97% impedance and 37% pattern bandwidth and a robust vehicle mounted omnidirectional antenna element having more than 85% impedance and pattern bandwidth.

scholarly journals Formation of additional virtual reception channels when processing signals at the outputs of elements of the antenna array of a promising cellular base station

2021 ◽  
Vol 24 (2) ◽  
pp. 79-87
Author(s):  
Alexander A. Bolkunov ◽  
Leonid A. Ovcharenko ◽  
Yuri G. Pasternak ◽  
Vladimir A. Pendyurin ◽  
Igor V. Popov ◽  
...  
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Antenna System ◽  
Base Station ◽  
Radio Sources ◽  
Linear Antenna ◽  
Frequency Range ◽  
The Earth ◽  
Receiving Antenna ◽  
Reception Mode

The results of research on the layout of the antenna array for a promising cellular base station in the frequency range 1,81,88 GHz, which includes a linear antenna array of 12 slotted elements with rectangular directors, the diagram forming scheme of which uses a modification of the Rotman lens, characterized in that for the sake of reducing its overall dimensions, the lens is folded in half the earth is located in the center, and on both sides of it-the halves of the lens body with exponential strip transformers. It is shown that to reduce the level of the side lobes of the antenna system in the reception mode, interpolation and extrapolation antenna arrays can be used. An extrapolation array can also be formed in order to increase the directional coefficient of the receiving antenna system and resolve radio sources that are not resolved by the real antenna array.

scholarly journals Comparative Analysis of Linear and Nonlinear Pattern Synthesis of Hemispherical Antenna Array Using Adaptive Evolutionary Techniques

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. R. Subhashini ◽  
A. T. Praveen Kumar
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
High Performance ◽  
Angular Position ◽  
Excitation Amplitude ◽  
Antenna Element ◽  
Pattern Synthesis ◽  
Conformal Antenna ◽  
Linear And Nonlinear ◽  
Nonlinear Pattern

Hemispherical antenna arrays are subjected to linear and nonlinear synthesis and are optimized using adaptive based differential evolution (ADE) and fire fly (AFA) algorithm. The hemispherical shaped array with isotropic elements is considered. Antenna element parameters that are used for synthesis are excitation amplitude and angular position. Linear synthesis is termed as the variation in the element excitation amplitude and nonlinear synthesis is process of variation in element angular position. Both ADE and AFA are a high-performance stochastic evolutionary algorithm used to solveN-dimensional problems. These methods are used to determine a set of parameters of antenna elements that provide the desired radiation pattern. The effectiveness of the algorithms for the design of conformal antenna array is shown by means of numerical results. Comparison with other methods is made whenever possible. The results reveal that nonlinear synthesis, aided by the discussed techniques, provides considerable enhancements compared to linear synthesis.

scholarly journals A beamforming study of the linear antenna array using grey wolf optimization algorithm

2020 ◽  
Vol 20 (3) ◽  
pp. 1538
Author(s):  
Asma Issa Mohsin ◽  
Asaad S. Daghal ◽  
Adheed Hasan Sallomi
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
High Performance ◽  
Optimization Problems ◽  
Linear Antenna ◽  
Grey Wolf ◽  
Sidelobe Level ◽  
Grey Wolf Optimization ◽  
Hunting Behavior ◽  
Code Division Multiple

<p><br />The grey wolf optimization (GWO) algorithm is considered an inspired meta-heuristic algorithm, which inspired by the social hierarchy and hunting behavior of the grey wolves. GWO has a high-performance capability of solving constrained, as well as unconstrained optimization problems. In this paper, the beamforming of smart antennas in a code division multiple access system based on the GWO algorithm is investigated. The sidelobe level (SLL) is minimized along with peak sidelobe level reduction, as well as an optimal beam pattern has been accomplished by using GWO to uniform linear antenna arrays. In this work, an amplitude is introduced as constant, while the interspacing distance between antenna array elements and the number of elements in a linear array are variables. The simulation results show that a faster convergence and likely high accurate beamforming are gained using GWO based method. Finally, it is shown that the GWO outperforms the genetic algorithm (GA) based method.</p>

scholarly journals High Gain Beam Steering Antenna Arrays with Low Scan Loss for mmWave Applications

2022 ◽  
Vol 72 (1) ◽  
pp. 67-72
Author(s):  
Anil Kumar Yerrola ◽  
Maifuz Ali ◽  
Ravi Kumar Arya ◽  
Lakhindar Murmu ◽  
Ashwani Kumar
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Patch Antenna ◽  
Beam Steering ◽  
High Gain ◽  
Microstrip Patch Antenna ◽  
Antenna Element ◽  
Array Design ◽  
Conformal Antenna ◽  
Microstrip Patch

In millimeter-wave (mmWave) communications, the antenna gain is a crucial parameter to overcome path loss and atmospheric attenuation. This work presents the design of two cylindrical conformal antenna arrays, made of modified rectangular microstrip patch antenna as a radiating element, working at 28 GHz for mmWave applications providing high gain and beam steering capability. The microstrip patch antenna element uses Rogers RO4232 substrate with a thickness of 0.5 mm and surface area of 5.8 mm × 5.8 mm. The individual antenna element provides a gain of 6.9 dBi with return loss bandwidth of 5.12 GHz. The first antenna array, made by using five conformal antenna elements, achieves a uniform gain of approximately 12 dBi with minimal scan loss for extensive scan angles. In the second antenna array, a dielectric superstrate using Rogers TMM (10i) was used to modify the first antenna array. It enhanced the gain to approximately 16 dBi while still maintaining low scan loss for wide angles. The proposed array design method is very robust and can be applied to any conformal surface. The mathematical equations are also provided to derive the array design, and both array designs are verified by using full-wave simulations.

scholarly journals THz CMOS On-Chip Antenna Array Using Defected Ground Structure

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1137
Author(s):  
Changmin Lee ◽  
Jinho Jeong
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
High Performance ◽  
High Gain ◽  
Antenna Element ◽  
Cmos Process ◽  
Defected Ground Structure ◽  
Ground Structure ◽  
On Chip Antenna ◽  
On Chip

In this paper, we design a THz CMOS on-chip patch antenna with defected ground structure (DGS) and utilize it to implement a broadband and high gain on-chip antenna array. It is verified from the simulation that the DGS not only can increase the gain and bandwidth of the antenna element, but also can increase the isolation between the antenna elements in the on-chip array. Therefore, it allows the design of the compact 1 × 2 and 2 × 2 on-chip antenna array with high gain and broad bandwidth. The element spacing and feedline structures of the antenna array are designed and optimized by the simulations. The designed antenna element, and 1 × 2 and 2 × 2 antenna arrays are fabricated in a commercial 65 nm CMOS process. In the on-wafer measurement, they exhibit an antenna gain of 3.1 dBi, 7.2 dBi, and 8.2 dBi with a bandwidth of 14.0%, 21.3%, and 28.0% for the reflection coefficient less than −10 dB, respectively, at 300 GHz. This result corresponds to very good performance compared to the reported THz CMOS on-chip antenna array. Therefore, the designed CMOS on-chip antenna element and array using DGS in this work can be effectively applied to build low-cost and high performance THz systems, because they can be fully implemented in a conventional CMOS process without requiring any additional processes or manufacturing techniques.

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