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In the present scenario, orthogonal frequency division multiplexing (OFDM) waveform technique is playing a significant part in smart hospitals. Still, its impact is not effective in smart hospitals due to the numerous limitations such as loss of bandwidth due to the use of guard band, spectrum leakage, high peak to average power (PAPR), high detection delay, and thus along. Right now, fifth-generation (5G) employment is becoming regularized around the world and the state-of-the-art radio system is expected to meet all the demands of smart hospitals. High spectrum access, massive capacity, high throughput, and low PAPR are the requirements of smart healthcare hospitals. The digital hospital has seen tremendous progression in bandwidth requirements. From transmitting medical images to wearable devices, networks must operate at maximum speeds to safeguard patient care. The selection of competent transmission technologies will play an important role in the regularization of digital hospitals equipped with 5G. In the projected work, we focus on the implementation of novel waveforms such as Non-orthogonal multiple access (NOMA), Universal filter multi-carrier (UFMC), and filter bank multi-carrier (FBMC) system. Several parameters such as power spectrum density, bit error rate, capacity, and PAPR of advanced waveforms and OFDM methods are analyzed and studied.
Arun Kumar; R. Dhanagopal; Mahmoud A. Albreem; Dac-Nhuong Le. A comprehensive study on the role of advanced technologies in 5G based smart hospital. Alexandria Engineering Journal 2021, 60, 5527 -5536.
AMA StyleArun Kumar, R. Dhanagopal, Mahmoud A. Albreem, Dac-Nhuong Le. A comprehensive study on the role of advanced technologies in 5G based smart hospital. Alexandria Engineering Journal. 2021; 60 (6):5527-5536.
Chicago/Turabian StyleArun Kumar; R. Dhanagopal; Mahmoud A. Albreem; Dac-Nhuong Le. 2021. "A comprehensive study on the role of advanced technologies in 5G based smart hospital." Alexandria Engineering Journal 60, no. 6: 5527-5536.
In this paper, a printed low-profile antenna with frequency and pattern reconfigurable functionality is designed in three modes. Each mode operates at different frequency bands and has several options available for pattern reconfiguration in these bands. The proposed antenna consists of eight pin-diode switches (S1 to S8). The switches S1 and S2, installed in the radiating patch, are used for frequency reconfigurability to control the operating bands of the antenna. The rest of the six switches (S3, S4, S5, S6, S7, and S8), loaded in the stubs on the rear side of the antenna, are used for pattern reconfiguration to control the main lobe beam steering. When all switches are off, the proposed antenna operates in a wideband mode, covering the 3.82-9.32 GHz frequency range. When S1 is on, the antenna resonates in the 3.5 GHz (3.09-4.17 GHz) band. When both S1 and S2 are on, the resonant band of the antenna is shifted to 2.5 GHz band (2.40-2.81 GHz). A very good impedance matching with a return loss of less than -10 dB is attained in these bands. The beam steering is done at each operating frequency by controlling the on and off states of the six pin-diode switches (S3, S4, S5, S6, S7, and S8). Depending on the state of the switches, the antenna can direct the beam in seven distinct directions at 4.2 GHz, 4.5 GHz, and 5 GHz. The main beam of the radiation pattern is steered in five different directions at 5.5 GHz, 3.5 GHz, and 2.6 GHz operating bands for the given state of the mentioned switches. The proposed antenna supports several sub-6 GHz 5G bands (2.6 GHz, 3.5 GHz, 4.2 GHz, 4.5 GHz, and 5 GHz) and can be used in handheld 5G devices.
Ikhlas Ahmad; Haris Dildar; Wasi Ur Rehman Khan; Syed Amir Ali Shah; Shakir Ullah; Sadiq Ullah; Syed Muhammad Umar; Mahmoud A. Albreem; Mohammed H. Alsharif; Kasturi Vasudevan. Design and Experimental Analysis of Multiband Compound Reconfigurable 5G Antenna for Sub-6 GHz Wireless Applications. Wireless Communications and Mobile Computing 2021, 2021, 1 -14.
AMA StyleIkhlas Ahmad, Haris Dildar, Wasi Ur Rehman Khan, Syed Amir Ali Shah, Shakir Ullah, Sadiq Ullah, Syed Muhammad Umar, Mahmoud A. Albreem, Mohammed H. Alsharif, Kasturi Vasudevan. Design and Experimental Analysis of Multiband Compound Reconfigurable 5G Antenna for Sub-6 GHz Wireless Applications. Wireless Communications and Mobile Computing. 2021; 2021 ():1-14.
Chicago/Turabian StyleIkhlas Ahmad; Haris Dildar; Wasi Ur Rehman Khan; Syed Amir Ali Shah; Shakir Ullah; Sadiq Ullah; Syed Muhammad Umar; Mahmoud A. Albreem; Mohammed H. Alsharif; Kasturi Vasudevan. 2021. "Design and Experimental Analysis of Multiband Compound Reconfigurable 5G Antenna for Sub-6 GHz Wireless Applications." Wireless Communications and Mobile Computing 2021, no. : 1-14.
Massive multiple-input multiple-output (MIMO) is playing a crucial role in the fifth generation (5G) and beyond 5G (B5G) communication systems. Unfortunately, the complexity of massive MIMO systems is tremendously increased when a large number of antennas and radio frequency chains (RF) are utilized. Therefore, a plethora of research efforts has been conducted to find the optimal precoding algorithm with lowest complexity. The main aim of this paper is to provide insights on such precoding algorithms to a generalist of wireless communications. The added value of this paper is that the classification of massive MIMO precoding algorithms is provided with easily distinguishable classes of precoding solutions. This paper covers linear precoding algorithms starting with precoders based on approximate matrix inversion methods such as the truncated polynomial expansion (TPE), the Neumann series approximation (NSA), the Newton iteration (NI), and the Chebyshev iteration (CI) algorithms. The paper also presents the fixed-point iteration-based linear precoding algorithms such as the Gauss-Seidel (GS) algorithm, the successive over relaxation (SOR) algorithm, the conjugate gradient (CG) algorithm, and the Jacobi iteration (JI) algorithm. In addition, the paper reviews the direct matrix decomposition based linear precoding algorithms such as the QR decomposition and Cholesky decomposition (CD). The non-linear precoders are also presented which include the dirty-paper coding (DPC), Tomlinson-Harashima (TH), vector perturbation (VP), and lattice reduction aided (LR) algorithms. Due to the necessity to deal with a high consuming power by the base station (BS) with a large number of antennas in massive MIMO systems, a special subsection is included to describe the characteristics of the peak-to-average power ratio precoding (PAPR) algorithms such as the constant envelope (CE) algorithm, approximate message passing (AMP), and quantized precoding (QP) algorithms. This paper also reviews the machine learning role in precoding techniques. Although many precoding techniques are essentially proposed for a small-scale MIMO, they have been exploited in massive MIMO networks. Therefore, this paper presents the application of small-scale MIMO precoding techniques for massive MIMO. This paper demonstrates the precoding schemes in promising multiple antenna technologies such as the cell-free massive MIMO (CF-M-MIMO), beamspace massive MIMO, and intelligent reflecting surfaces (IRSs). In-depth discussion on the pros and cons, performance-complexity profile, and implementation solidity is provided. This paper also provides a discussion on the channel estimation and energy efficiency. This paper also presents potential future directions in massive MIMO precoding algorithms.
Mahmoud A. Albreem; Alaa H. Al Habbash; Ammar M. Abu-Hudrouss; Salama S. Ikki. Overview of Precoding Techniques for Massive MIMO. IEEE Access 2021, 9, 60764 -60801.
AMA StyleMahmoud A. Albreem, Alaa H. Al Habbash, Ammar M. Abu-Hudrouss, Salama S. Ikki. Overview of Precoding Techniques for Massive MIMO. IEEE Access. 2021; 9 ():60764-60801.
Chicago/Turabian StyleMahmoud A. Albreem; Alaa H. Al Habbash; Ammar M. Abu-Hudrouss; Salama S. Ikki. 2021. "Overview of Precoding Techniques for Massive MIMO." IEEE Access 9, no. : 60764-60801.
Green wireless networking has attracted considerable research attention, especially in academics and industry from economic and ecological perspectives. Promoting wireless infrastructures by exploiting green power sources has the potential to enhance sustainability and address the adverse impact of conventional power sources. A sustainable optimal standalone solar-powered model for green cellular base stations in urban locations of South Korea is proposed in this work to extend 24-hour uninterrupted power supply support to LTE cellular base stations (BSs) and take advantage of integrated storage devices. The optimal system architecture, energy management, and economic analysis are examined using the hybrid optimization model for electric renewable optimization software based on actual prevailing conditions of regions and their technical feasibility. Results showed that the proposed solar photovoltaic system can achieve significant operational expenditure savings of up to 43% and 43.58% in on- and off-grid sites, respectively, and reduce greenhouse gas emissions in the telecommunications sector. Moreover, the results of this study can provide a stronger platform for a sustainable green wireless network paradigm that can ensure energy sustainability compared with conventional technology.
Mohammed H. Alsharif; Raju Kannadasan; Abu Jahid; Mahmoud A. Albreem; Jamel Nebhen; Bong Jun Choi. Long-Term Techno-Economic Analysis of Sustainable and Zero Grid Cellular Base Station. IEEE Access 2021, 9, 54159 -54172.
AMA StyleMohammed H. Alsharif, Raju Kannadasan, Abu Jahid, Mahmoud A. Albreem, Jamel Nebhen, Bong Jun Choi. Long-Term Techno-Economic Analysis of Sustainable and Zero Grid Cellular Base Station. IEEE Access. 2021; 9 (99):54159-54172.
Chicago/Turabian StyleMohammed H. Alsharif; Raju Kannadasan; Abu Jahid; Mahmoud A. Albreem; Jamel Nebhen; Bong Jun Choi. 2021. "Long-Term Techno-Economic Analysis of Sustainable and Zero Grid Cellular Base Station." IEEE Access 9, no. 99: 54159-54172.
Internet of things (IoT) is one of key pillars in fifth generation (5G) and beyond 5G (B5G) networks. It is estimated to have 42 billion IoT devices by the year 2025. Currently, carbon emissions and electronic waste (e-waste) are significant challenges in the information & communication technologies (ICT) sector. The aim of this article is to provide insights on green IoT (GIoT) applications, practices, awareness, and challenges to a generalist of wireless communications. We garner various efficient enablers, architectures, environmental impacts, technologies, energy models, and strategies, so that a reader can find a wider range of GIoT knowledge. In this article, various energy efficient hardware design principles, data-centers, and software based data traffic management techniques are discussed as enablers of GIoTs. Energy models of IoT devices are presented in terms of data communication, actuation process, static power dissipation and generated power by harvesting techniques for optimal power budgeting. In addition, this article presents various effective behavioral change models and strategies to create awareness about energy conservation among users and service providers of IoTs. Fog/Edge computing offers a platform that extends cloud services at the edge of network and hence reduces latency, alleviates power consumption, offers improved mobility, bandwidth, data privacy, and security. Therefore, we present the energy consumption model of a fog-based service under various scenarios. Problems related to ever increasing data in IoT networks can be solved by integrating artificial intelligence (AI) along with machine learning (ML) models in IoT networks. Therefore, this article provides insights on role of the ML in the GIoT. We also present how legislative policies support adoption of recycling process by various stakeholders. In addition, this article is presenting future research goals towards energy efficient hardware design principles and a need of coordination between policy makers, IoT devices manufacturers along with service providers.
Mahmoud A. Albreem; Abdul Manan Sheikh; Mohammed H. Alsharif; Muzammil Jusoh; Mohd Najib Mohd Yasin. Green Internet of Things (GIoT): Applications, Practices, Awareness, and Challenges. IEEE Access 2021, 9, 38833 -38858.
AMA StyleMahmoud A. Albreem, Abdul Manan Sheikh, Mohammed H. Alsharif, Muzammil Jusoh, Mohd Najib Mohd Yasin. Green Internet of Things (GIoT): Applications, Practices, Awareness, and Challenges. IEEE Access. 2021; 9 ():38833-38858.
Chicago/Turabian StyleMahmoud A. Albreem; Abdul Manan Sheikh; Mohammed H. Alsharif; Muzammil Jusoh; Mohd Najib Mohd Yasin. 2021. "Green Internet of Things (GIoT): Applications, Practices, Awareness, and Challenges." IEEE Access 9, no. : 38833-38858.
Fifth generation wireless communication system is implemented by several mobile companies where important technologies are employed such as the massive multiple-input multiple-output (MIMO). Although it improves the spectrum and energy efficiencies, it is not a trivial to propose an efficient detector for massive MIMO systems because a large number of antennas increases the computational complexity. In this paper, approximate message passing (AMP) is exploited in the massive MIMO uplink (UL) data detection. Although the AMP method is suffering from a considerable performance in special cases, an efficient selection of the initial solution affects greatly the convergence rate, the bit-error-rate performance, and the computational complexity. In this paper, three efficient initialization methods of the AMP-based massive MIMO UL detector are proposed based on iterative methods, namely, the successive overrelaxation, the Gauss–Seidel, and the Jacobi. In addition, a stair matrix is exploited to achieve high convergence rate. Numerical results show that the proposed detector achieved a considerable performance improvement and complexity reduction in comparison with the traditional AMP-based detector.
Mahmoud A. Albreem. A Low Complexity Detector for Massive MIMO Uplink Systems. National Academy Science Letters 2021, 1 -5.
AMA StyleMahmoud A. Albreem. A Low Complexity Detector for Massive MIMO Uplink Systems. National Academy Science Letters. 2021; ():1-5.
Chicago/Turabian StyleMahmoud A. Albreem. 2021. "A Low Complexity Detector for Massive MIMO Uplink Systems." National Academy Science Letters , no. : 1-5.
Alaa H. Al Habbash; Ammar M. Abu-Hudrouss; Mohammed Taha O. El Astal; Mahmoud A. Albreem; Salama S. Ikki. Extended Signed Quadrature Spatial Modulation System With Multi-User Support. IEEE Transactions on Broadcasting 2021, 1 -11.
AMA StyleAlaa H. Al Habbash, Ammar M. Abu-Hudrouss, Mohammed Taha O. El Astal, Mahmoud A. Albreem, Salama S. Ikki. Extended Signed Quadrature Spatial Modulation System With Multi-User Support. IEEE Transactions on Broadcasting. 2021; ():1-11.
Chicago/Turabian StyleAlaa H. Al Habbash; Ammar M. Abu-Hudrouss; Mohammed Taha O. El Astal; Mahmoud A. Albreem; Salama S. Ikki. 2021. "Extended Signed Quadrature Spatial Modulation System With Multi-User Support." IEEE Transactions on Broadcasting , no. : 1-11.
Massive multiple-input multiple-output (MIMO) is a backbone technology in the fifth-generation (5G) and beyond 5G (B5G) networks. It enhances performance gain, energy efficiency, and spectral efficiency. Unfortunately, a massive number of antennas need sophisticated processing to detect the transmitted signal. Although a detector based on the maximum likelihood (ML) is optimal, it incurs a high computational complexity, and hence, it is not hardware-friendly. In addition, the conventional linear detectors, such as the minimum mean square error (MMSE), include a matrix inversion, which causes a high computational complexity. As an alternative solution, approximate message passing (AMP) algorithm is proposed for data detection in massive MIMO uplink (UL) detectors. Although the AMP algorithm is converging extremely fast, the convergence is not guaranteed. A good initialization influences the convergence rate and affects the performance substantially together and the complexity. In this paper, we exploit several free-matrix-inversion methods, namely, the successive over-relaxation (SOR), the Gauss–Seidel (GS), and the Jacobi (JA), to initialize the AMP-based massive MIMO UL detector. In other words, hybrid detectors are proposed based on AMP, JA, SOR, and GS with an efficient initialization. Numerical results show that proposed detectors achieve a significant performance enhancement and a large reduction in the computational complexity.
Mahmoud Albreem; Arun Kumar; Mohammed Alsharif; Imran Khan; Bong Choi. Comparative Analysis of Data Detection Techniques for 5G Massive MIMO Systems. Sustainability 2020, 12, 9281 .
AMA StyleMahmoud Albreem, Arun Kumar, Mohammed Alsharif, Imran Khan, Bong Choi. Comparative Analysis of Data Detection Techniques for 5G Massive MIMO Systems. Sustainability. 2020; 12 (21):9281.
Chicago/Turabian StyleMahmoud Albreem; Arun Kumar; Mohammed Alsharif; Imran Khan; Bong Choi. 2020. "Comparative Analysis of Data Detection Techniques for 5G Massive MIMO Systems." Sustainability 12, no. 21: 9281.
With the rapid increase in the development of a cellular communication system, remote health monitoring and smart health care are improving and getting through a swift transformation. Currently, we are utilizing the advance long term evolution (A-LTE) network to support the modern health care. Nevertheless, smart hospital/health concern is not fully evolved all around the world. The rollout of the fifth generation (5G) will improve the standard of the smart health care. However, requirements of a smart hospital will be different as compared to other applications such as education, industries, and the public. The smart hospital will be connected 24/7, with several small devices integrated with the sensors. In simple words, the future smart hospital will be based on the 5G and the internet of things (IoT), expected to augment the system coverage, effectiveness, and throughput of the system. Further, high speed, low latency, spectral efficiency, and low energy consumption are the requirements of the 5G based modern hospital. In this correspondence, we focused to improve the latency, spectrum, and throughput of the 5G network by implementing a hybrid detection technique based on the QR decomposition and the M algorithm-maximum likelihood detection (QRM-MLD) and beamforming (BF) for massive multiple-input multiple-output (MIMO) and non-orthogonal multiple access (NOMA) system. In addition, a comparison between the proposed and conventional detection techniques is presented. The proposed hybrid detection technique improves the throughput of the system and reduces the computational complexity as compared to the conventional QRM-MLD algorithm, conventional BF and zero-forcing (ZF) techniques on the platform of several parameters i.e. complexity, bit error rate (BER), peak power, etc.
Arun Kumar; Mahmoud A. Albreem; Manoj Gupta; Mohammed H. Alsharif; Sunghwan Kim. Future 5G Network Based Smart Hospitals: Hybrid Detection Technique for Latency Improvement. IEEE Access 2020, 8, 153240 -153249.
AMA StyleArun Kumar, Mahmoud A. Albreem, Manoj Gupta, Mohammed H. Alsharif, Sunghwan Kim. Future 5G Network Based Smart Hospitals: Hybrid Detection Technique for Latency Improvement. IEEE Access. 2020; 8 (99):153240-153249.
Chicago/Turabian StyleArun Kumar; Mahmoud A. Albreem; Manoj Gupta; Mohammed H. Alsharif; Sunghwan Kim. 2020. "Future 5G Network Based Smart Hospitals: Hybrid Detection Technique for Latency Improvement." IEEE Access 8, no. 99: 153240-153249.
The initial solution of a massive multiple-input multiple-output (M-MIMO) detector for uplink (UL) is greatly influence the balance between the bit error rate (BER) performance and the computational complexity. Although the maximum likelihood (ML) detector obtains the best BER performance, it has an extremely high computational complexity. Iterative linear minimum mean square error (MMSE) detector based on the Gauss–Seidel (GS), the successive over-relaxation (SOR), and the Jacobi (JA), obtains a good performance-complexity profile when the base station (BS)-to-user-antenna-ratio (BUAR) is large. However, when the BUAR is small, the system suffers from a considerable performance loss. In this paper, a hybrid detector based on the joint GS and SOR methods is proposed where the initial solution is determined by the first iteration of GS method. Numerical results show a considerable complexity reduction and performance enhancement using the proposed GS-SOR method over all methods when the BUAR is small.
Mahmoud A. M. Albreem; K. Vasudevan. Efficient Hybrid Linear Massive MIMO Detector Using Gauss–Seidel And Successive Over-Relaxation. International Journal of Wireless Information Networks 2020, 27, 551 -557.
AMA StyleMahmoud A. M. Albreem, K. Vasudevan. Efficient Hybrid Linear Massive MIMO Detector Using Gauss–Seidel And Successive Over-Relaxation. International Journal of Wireless Information Networks. 2020; 27 (4):551-557.
Chicago/Turabian StyleMahmoud A. M. Albreem; K. Vasudevan. 2020. "Efficient Hybrid Linear Massive MIMO Detector Using Gauss–Seidel And Successive Over-Relaxation." International Journal of Wireless Information Networks 27, no. 4: 551-557.
The standardization activities of the fifth generation communications are clearly over and deployment has commenced globally. To sustain the competitive edge of wireless networks, industrial and academia synergy have begun to conceptualize the next generation of wireless communication systems (namely, sixth generation, (6G)) aimed at laying the foundation for the stratification of the communication needs of the 2030s. In support of this vision, this study highlights the most promising lines of research from the recent literature in common directions for the 6G project. Its core contribution involves exploring the critical issues and key potential features of 6G communications, including: (i) vision and key features; (ii) challenges and potential solutions; and (iii) research activities. These controversial research topics were profoundly examined in relation to the motivation of their various sub-domains to achieve a precise, concrete, and concise conclusion. Thus, this article will contribute significantly to opening new horizons for future research directions.
Mohammed H. Alsharif; Anabi Hilary Kelechi; Mahmoud A. Albreem; Shehzad Ashraf Chaudhry; M. Sultan Zia; Sunghwan Kim. Sixth Generation (6G) Wireless Networks: Vision, Research Activities, Challenges and Potential Solutions. Symmetry 2020, 12, 676 .
AMA StyleMohammed H. Alsharif, Anabi Hilary Kelechi, Mahmoud A. Albreem, Shehzad Ashraf Chaudhry, M. Sultan Zia, Sunghwan Kim. Sixth Generation (6G) Wireless Networks: Vision, Research Activities, Challenges and Potential Solutions. Symmetry. 2020; 12 (4):676.
Chicago/Turabian StyleMohammed H. Alsharif; Anabi Hilary Kelechi; Mahmoud A. Albreem; Shehzad Ashraf Chaudhry; M. Sultan Zia; Sunghwan Kim. 2020. "Sixth Generation (6G) Wireless Networks: Vision, Research Activities, Challenges and Potential Solutions." Symmetry 12, no. 4: 676.
Massive multiple-input multiple-output (M-MIMO) is a substantial pillar in fifth generation (5G) mobile communication systems. Although the maximum likelihood (ML) detector attains the optimum performance, it has an exponential complexity. Linear detectors are one of the substitutions and they are comparatively simple to implement. Unfortunately, they sustain a considerable performance loss in high loaded systems. They also include a matrix inversion which is not hardware-friendly. In addition, if the channel matrix is singular or nearly singular, the system will be classified as an ill-conditioned and hence, the signal cannot be equalized. To defeat the inherent noise enhancement, iterative matrix inversion methods are used in the detectors’ design where approximate matrix inversion is replacing the exact computation. In this paper, we study a linear detector based on iterative matrix inversion methods in realistic radio channels called QUAsi Deterministic RadIo channel GenerAtor (QuaDRiGa) package. Numerical results illustrate that the conjugate-gradient (CG) method is numerically robust and obtains the best performance with lowest number of multiplications. In the QuaDRiGA environment, iterative methods crave large n to obtain a pleasurable performance. This paper also shows that when the ratio between the user antennas and base station (BS) antennas ( β ) is close to 1, iterative matrix inversion methods are not attaining a good detector’s performance.
Mahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. A Low Complexity Near-Optimal Iterative Linear Detector for Massive MIMO in Realistic Radio Channels of 5G Communication Systems. Entropy 2020, 22, 388 .
AMA StyleMahmoud A. Albreem, Mohammed H. Alsharif, Sunghwan Kim. A Low Complexity Near-Optimal Iterative Linear Detector for Massive MIMO in Realistic Radio Channels of 5G Communication Systems. Entropy. 2020; 22 (4):388.
Chicago/Turabian StyleMahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. 2020. "A Low Complexity Near-Optimal Iterative Linear Detector for Massive MIMO in Realistic Radio Channels of 5G Communication Systems." Entropy 22, no. 4: 388.
Fifth-generation (5G) communications system is commercially introduced by several mobile operators where sub-6 GHz bands are the backbone of the 5G networks. A large-scale multiple-input multiple-output (MIMO), or massive MIMO (mMIMO), technology has a major impact to secure high data rate, high spectral efficiency, and quality of service (QoS). It could also have a major role in the beyond-5G systems. A massive number of antennas seek advanced signal processing to detect and equalize the signal. However, optimal detectors, such as the maximum likelihood (ML) and maximum posterior (MAP), are not desirable in implementation due to extremely high complexity. Therefore, sub-optimum solutions have been introduced to obtain and guarantee enough balance between the performance and the computational complexity. In this paper, a robust and joint low complexity detection algorithm is proposed based on the Jacobi (JA) and Gauss–Seidel (GS) methods. In such iterative methods, the performance, complexity, and convergence rate are highly dependent on the initial vector. In this paper, initial solution is proposed by exploiting the benefits of a stair matrix to obtain a fast convergence rate, high performance, and low complexity. Numerical results show that proposed algorithm achieves high accuracy and relieve the computational complexity even when the BS-to-user-antenna ratio (BUAR) is small.
Mahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. A Robust Hybrid Iterative Linear Detector for Massive MIMO Uplink Systems. Symmetry 2020, 12, 306 .
AMA StyleMahmoud A. Albreem, Mohammed H. Alsharif, Sunghwan Kim. A Robust Hybrid Iterative Linear Detector for Massive MIMO Uplink Systems. Symmetry. 2020; 12 (2):306.
Chicago/Turabian StyleMahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. 2020. "A Robust Hybrid Iterative Linear Detector for Massive MIMO Uplink Systems." Symmetry 12, no. 2: 306.
In massive multiple-input multiple-output (M-MIMO) systems, a detector based on maximum likelihood (ML) algorithm attains optimum performance, but it exhaustively searches all possible solutions, hence, it has a very high complexity and realization is denied. Linear detectors are an alternative solution because of low complexity and simplicity in implementation. Unfortunately, they culminate in a matrix inversion that increases the computational complexity in high loaded systems. Therefore, several iterative methods have been proposed to approximate or avoid the matrix inversion, such as the Neuamnn series (NS), Newton iterations (NI), successive overrelaxation (SOR), Gauss–Siedel (GS), Jacobi (JA), and Richardson (RI) methods. However, a detector based on iterative methods requires a pre-processing and initialization where good initialization impresses the convergence, the performance, and the complexity. Most of the existing iterative linear detectors are using a diagonal matrix ( D ) in initialization because the equalization matrix is almost diagonal. This paper studies the impact of utilizing a stair matrix ( S ) instead of D in initializing the linear M-MIMO uplink (UL) detector. A comparison between iterative linear M-MIMO UL detectors with D and S is presented in performance and computational complexity. Numerical Results show that utilization of S achieves the target performance within few iterations, and, hence, the computational complexity is reduced. A detector based on the GS and S achieved a satisfactory bit-error-rate (BER) with the lowest complexity.
Mahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. Impact of Stair and Diagonal Matrices in Iterative Linear Massive MIMO Uplink Detectors for 5G Wireless Networks. Symmetry 2020, 12, 71 .
AMA StyleMahmoud A. Albreem, Mohammed H. Alsharif, Sunghwan Kim. Impact of Stair and Diagonal Matrices in Iterative Linear Massive MIMO Uplink Detectors for 5G Wireless Networks. Symmetry. 2020; 12 (1):71.
Chicago/Turabian StyleMahmoud A. Albreem; Mohammed H. Alsharif; Sunghwan Kim. 2020. "Impact of Stair and Diagonal Matrices in Iterative Linear Massive MIMO Uplink Detectors for 5G Wireless Networks." Symmetry 12, no. 1: 71.
Several approximate matrix inversion methods have been used in linear massive MIMO uplink detectors where their convergence rate, performance, and complexity are greatly affected by the initial solution. In this Letter, the authors exploit a stair matrix, instead of a diagonal matrix, in initialising iterative linear minimum mean square error massive MIMO detector based on several approximate matrix inversion methods, namely, the Gauss–Seidel, successive over relaxation, Richardson iteration, and Newton iteration methods. Numerical results show a significant performance enhancement without a burden of extra complexity using a stair matrix over a diagonal matrix in all methods.
M. Albreem; M. Juntti; S. Shahabuddin. Efficient initialisation of iterative linear massive MIMO detectors using a stair matrix. Electronics Letters 2020, 56, 50 -52.
AMA StyleM. Albreem, M. Juntti, S. Shahabuddin. Efficient initialisation of iterative linear massive MIMO detectors using a stair matrix. Electronics Letters. 2020; 56 (1):50-52.
Chicago/Turabian StyleM. Albreem; M. Juntti; S. Shahabuddin. 2020. "Efficient initialisation of iterative linear massive MIMO detectors using a stair matrix." Electronics Letters 56, no. 1: 50-52.
Wireless networks employing millimeter-wave (mmWave) and Massive Multiple-Input Multiple-Output (MIMO) technologies are a key approach to boost network capacity, coverage, and quality of service (QoS) for future communications. They deploy symmetric antennas on a large scale in order to enhance the system throughput and data rate. However, increasing the number of antennas and Radio Frequency (RF) chains results in high computational complexity and more energy requirements. Therefore, to solve these problems, this paper proposes a low-complexity hybrid beamforming scheme for mmWave Massive-MIMO 5G wireless networks. The proposed algorithm is on the basis of alternating the minimum mean square error (Alt-MMSE) hybrid beamforming technique in which the orthogonal properties of the digital matrix were designed, and then the MSE of the transmitted and received signal was reduced. The phase of the analog matrix was obtained from the updated digital matrix. Simulation results showed that the proposed hybrid beamforming algorithm had better performance than existing state-of-the-art algorithms, and similar performance with the optimal digital precoding algorithm.
Saleem Latteef Mohammed; Mohammed H. Alsharif; Sadik Kamel Gharghan; Imran Khan; Mahmoud Albreem. Robust Hybrid Beamforming Scheme for Millimeter-Wave Massive-MIMO 5G Wireless Networks. Symmetry 2019, 11, 1424 .
AMA StyleSaleem Latteef Mohammed, Mohammed H. Alsharif, Sadik Kamel Gharghan, Imran Khan, Mahmoud Albreem. Robust Hybrid Beamforming Scheme for Millimeter-Wave Massive-MIMO 5G Wireless Networks. Symmetry. 2019; 11 (11):1424.
Chicago/Turabian StyleSaleem Latteef Mohammed; Mohammed H. Alsharif; Sadik Kamel Gharghan; Imran Khan; Mahmoud Albreem. 2019. "Robust Hybrid Beamforming Scheme for Millimeter-Wave Massive-MIMO 5G Wireless Networks." Symmetry 11, no. 11: 1424.
Massive multiple-input multiple-output (MIMO) is a key technology to meet the user demands in performance and quality of services (QoS) for next generation communication systems. Due to a large number of antennas and radio frequency (RF) chains, complexity of the symbol detectors increased rapidly in a massive MIMO uplink receiver. Thus, the research to find the perfect massive MIMO detection algorithm with optimal performance and low complexity has gained a lot of attention during the past decade. A plethora of massive MIMO detection algorithms has been proposed in the literature. The aim of this paper is to provide insights on such algorithms to a generalist of wireless communications. We garner the massive MIMO detection algorithms and classify them so that a reader can find a distinction between different algorithms from a wider range of solutions. We present optimal and near-optimal detection principles specifically designed for the massive MIMO system such as detectors based on a local search, belief propagation and box detection. In addition, we cover detectors based on approximate inversion, which has gained popularity among the VLSI signal processing community due to their deterministic dataflow and low complexity. We also briefly explore several nonlinear small-scale MIMO (2-4 antenna receivers) detectors and their applicability in the massive MIMO context. In addition, we present recent advances of detection algorithms which are mostly based on machine learning or sparsity based algorithms. In each section, we also mention the related implementations of the detectors. A discussion of the pros and cons of each detector is provided.
Mahmoud A. Albreem; Markku Juntti; Shahriar Shahabuddin. Massive MIMO Detection Techniques: A Survey. IEEE Communications Surveys & Tutorials 2019, 21, 3109 -3132.
AMA StyleMahmoud A. Albreem, Markku Juntti, Shahriar Shahabuddin. Massive MIMO Detection Techniques: A Survey. IEEE Communications Surveys & Tutorials. 2019; 21 (4):3109-3132.
Chicago/Turabian StyleMahmoud A. Albreem; Markku Juntti; Shahriar Shahabuddin. 2019. "Massive MIMO Detection Techniques: A Survey." IEEE Communications Surveys & Tutorials 21, no. 4: 3109-3132.
Sufficient and uninterrupted electricity supply is one of the main factors to develop the country. Today, electricity can be generated using a variety of sources, whether from non-renewable sources as well as renewable resources. To generate electrical power, Malaysia can't rely entirely on non-renewable resources such as petroleum and coal as these are finite resources which are experiencing depletion around the world. Electricity generated from renewable sources such as water, particularly from micro hydropower systems is considered the cheapest and most environmentally friendly source of electrical energy. Based on the reconnaissance study conducted, the streams of flowing water in Gua Kelam have the potential to yield about 34.29 kW of electricity power, based on the head height of 27 m and flow rate 0.216 m3/s. In this paper, a model for an ordinary micro hydropower facility has been proposed. It links various electromechanical equipment consisting of a hydraulic turbine governor, and a synchronous generator. The modeling was executed to design a micro hydropower system as an alternative source of supply of electricity to Gua Kelam, Perlis. The proposed model was tested by placing a three-phase fault to earth for the purpose of testing the reliability of the system. With the selection of an appropriate control system, the proposed model is very suitable for the development of micro hydropower system at a potential site such as Gua Kelam.
Mamoud A. M. Albreem; Rosnita Md Aspan. Micro Hydropower System Design for Gua Kelam Electricity Supply. International Journal of Applied Power Engineering (IJAPE) 2018, 7, 120 -128.
AMA StyleMamoud A. M. Albreem, Rosnita Md Aspan. Micro Hydropower System Design for Gua Kelam Electricity Supply. International Journal of Applied Power Engineering (IJAPE). 2018; 7 (2):120-128.
Chicago/Turabian StyleMamoud A. M. Albreem; Rosnita Md Aspan. 2018. "Micro Hydropower System Design for Gua Kelam Electricity Supply." International Journal of Applied Power Engineering (IJAPE) 7, no. 2: 120-128.