Fifth-generation (5G) cellular networks will almost certainly operate in the high-bandwidth, underutilized millimeter-wave (mmWave) frequency spectrum, which offers the potentiality of high-capacity wireless transmission of multi-gigabit-per-second (Gbps) data rates. Despite the enormous available bandwidth potential, mmWave signal transmissions suffer from fundamental technical challenges like severe path loss, sensitivity to blockage, directivity, and narrow beamwidth, due to its short wavelengths. To effectively support system design and deployment, accurate channel modeling comprising several 5G technologies and scenarios is essential. This survey provides a comprehensive overview of several emerging technologies for 5G systems, such as massive multiple-input multiple-output (MIMO) technologies, multiple access technologies, hybrid analog-digital precoding and combining, non-orthogonal multiple access (NOMA), cell-free massive MIMO, and simultaneous wireless information and power transfer (SWIPT) technologies. These technologies induce distinct propagation characteristics and establish specific requirements on 5G channel modeling. To tackle these challenges, we first provide a survey of existing solutions and standards and discuss the radio-frequency (RF) spectrum and regulatory issues for mmWave communications. Second, we compared existing wireless communication techniques like sub-6-GHz WiFi and sub-6 GHz 4G LTE over mmWave communications which come with benefits comprising narrow beam, high signal quality, large capacity data transmission, and strong detection potential. Third, we describe the fundamental propagation characteristics of the mmWave band and survey the existing channel models for mmWave communications. Fourth, we track evolution and advancements in hybrid beamforming for massive MIMO systems in terms of system models of hybrid precoding architectures, hybrid analog and digital precoding/combining matrices, with the potential antenna configuration scenarios and mmWave channel estimation (CE) techniques. Fifth, we extend the scope of the discussion by including multiple access technologies for mmWave systems such as non-orthogonal multiple access (NOMA) and space-division multiple access (SDMA), with limited RF chains at the base station. Lastly, we explore the integration of SWIPT in mmWave massive MIMO systems, with limited RF chains, to realize spectrally and energy-efficient communications.

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A Comprehensive Survey on Millimeter Wave Communications for Fifth-Generation Wireless Networks: Feasibility and Challenges

Linear and circular arrays are optimized using the particle swarm optimization (PSO) method. Also, arrays of isotropic and cylindrical dipole elements are considered. The parameters of isotropic arrays are elements excitation amplitude, excitation phase and locations, while for dipole array the optimized parameters are elements excitation amplitude, excitation phase, location, and length. PSO is a high-performance stochastic evolutionary algorithm used to solve N-dimensional problems. The method of PSO is used to determine a set of parameters of antenna elements that provide the goal radiation pattern. The efiectiveness of PSO for the design of antenna arrays is shown by means of numerical results. Comparison with other methods is made whenever possible. The results reveal that design of antenna arrays using the PSO method provides considerable enhancements compared with the uniform array and the synthesis obtained from other optimization techniques.

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Linear and Circular Array Optimization: a Study Using Particle Swarm Intelligence

In this paper, circular and hexagonal array geometries for smart antenna applications are compared. Uniform circular (UCA) and hexagonal arrays (UHA) with 18 half-wave dipole elements are examined; also planar (2 concentric rings of radiators) uniform circular (PUCA) and hexagonal arrays (PUHA) are considered. The effect of rotating the outer ring of the PUCA is studied. In our analysis, the method of moments is used to compute the response of the uniform circular and hexagonal dipole arrays in a mutual coupling environment. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations, amplitudes and phases, of the adaptive arrays elements for beamforming.

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A Comparison Between Circular and Hexagonal Array Geometries for Smart Antenna Systems Using Particle Swarm Optimization Algorithm

Particle swarm optimization (PSO) is an evolutionary algorithm based on the bird fly. Differential evolution (DE) is a vector population based stochastic optimization method. The fact that both algorithms can handle efficiently arbitrary optimization problems has made them popular for solving problems in electromagnetics. In this paper, we apply a design technique based on a self-adaptive DE (SADE) algorithm to real-valued antenna and microwave design problems. These include linear-array synthesis, patch-antenna design and microstrip filter design. The number of unknowns for the design problems varies from 6 to 60. We compare the self-adaptive DE strategy with popular PSO and DE variants. We evaluate the algorithms' performance regarding statistical results and convergence speed. The results obtained for different problems show that the DE algorithms outperform the PSO variants in terms of finding best optima. Thus, our results show the advantages of the SADE strategy and the DE in general. However, these results are considered to be indicative and do not generally apply to all optimization problems in electromagnetics.

Self-Adaptive Differential Evolution Applied to Real-Valued Antenna and Microwave Design Problems

A dualband coplanar waveguide (CPW)-fed planar monopole antenna suitable for WLAN application is presented in this paper. The antenna resembling as a "G" shape and optimally designed by using the particle swarm optimization (PSO) algorithm can produce dual resonant modes and a much wider impedance bandwidth for the higher band. Prototypes of the obtained optimized antenna have been constructed and tested. The measured results explore good dualband operation with −10 dB impedance bandwidths of 9.7% and 62.8% at bands of 2.43 and 4.3 GHz, respectively, which cover the 2.4/5.2/5.8 GHz WLAN operating bands, and show good agreement with the numerical prediction. Also, good antenna performances such as radiation patterns and antenna gains over the operating bands have been observed.

/pdf/optimal-design-of-dualband-cpw-fed-g-shaped-monopole-antenna-5eb6pwnz3k.pdf

Optimal design of dualband cpw-fed g-shaped monopole antenna for wlan application

In this article, the particle swarm optimization algorithm is used to calculate the complex excitations, amplitudes and phases, of the adaptive circular array elements. To illustrate the performance of this method for steering a signal in the desired direction and imposing nulls in the direction of interfering signals by controlling the complex excitation of each array element, two types of arrays are considered. A uniform circular array (UCA) and a planar uniform circular array (PUCA) with 16 elements of half-wave dipoles are examined. Also, the performance of an adaptive array using 3-bit amplitude and 4-bit phase shifters are studied. In our analysis, the method of moments is used to estimate the response of the dipole UCAs in a mutual coupling environment. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.

Analysis of uniform circular arrays for adaptive beamforming applications using particle swarm optimization algorithm

In this paper we evaluate the potential of a 5-element monopole array incorporated into a handheld device for beamforming in the 5.0-GHz band. The geometry of the handset consists of a 5-element array: four elements located at the handset corners and the fifth-element located at the center. Also, the interaction of the antenna array, mounted on a mobile handset, with a human head phantom is investigated. Firstly, the spatial peak specific absorption rate (SAR) values of 5-element array antennas for mobile handsets in the vicinity of a spherical phantom of a human head are evaluated numerically as a function of the distance between the handset and the head phantom for two different scenarios. Next, the effect of the human head on the handset radiation pattern is studied. The effect of different handset positions on the radiation pattern is also considered. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations of the adaptive arrays elements in a mutual coupling environment for beamforming synthesis. All numerical simulations are performed using the FEKO Suite 5.3

https://www.jpier.org/pierc/pierc02/12.08032405.pdf

Investigating the interaction between a human head and a smart handset for 4g mobile communication systems

The orthogonal method is used to improve the patterns of the linear array in the presence of failed elements. Reconfiguration of the amplitude and phase distributions of the remaining elements can partially compensate for the failed elements and thus reduce the sidelobe level. Numerical results are presented to illustrate the effectiveness of the method. The effect of the number of failed elements, the distance between the elements and the shape of the desired pattern is demonstrated through this paper.

http://ieeexplore.ieee.org/iel5/9234/29272/01321774.pdf

Array failure correction with orthogonal method

In this paper, a circular Yagi-Uda array (CYUA) for smart antenna applications is designed using the lengths and spacings from the optimum design of a three-element linear Yagi-Uda antenna. Then a modified circular Yagi-Uda array (MCYUA) is developed by adding 5 circular connecting wires to the inner parasitic elements (reflectors) to form a wire grid cylinder. The results are compared with those for uniform circular array (UCA) with 12 half-wave dipole elements. In our analysis, the method of moments (MoM) is used to compute the response of the arrays in a mutual coupling environment. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations of the adaptive arrays elements for beamforming.

S.M.M. Ibrahem

Papers

A Comparison Between Circular and Hexagonal Array Geometries for Smart Antenna Systems Using Particle Swarm Optimization Algorithm

Analysis of uniform circular arrays for adaptive beamforming applications using particle swarm optimization algorithm

Investigating the interaction between a human head and a smart handset for 4g mobile communication systems

Array failure correction with orthogonal method

Performance of Circular Yagi-Uda Arrays for Beamforming Applications Using Particle Swarm Optimization Algorithm