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This study introduces a novel, highly compact broadband millimeter-wave (mm-wave) antenna design and its Multiple-Input-Multiple-Output (MIMO) configuration proposed for 28 GHz applications targeting 5G networks. The antenna is designed over a 0.25 mm thick Rogers RT5880LZ substrate having a relative dielectric permittivity of 2 and an overall size of 16 mm × 16 mm. Its MIMO configuration utilizes polarization diversity and includes four elliptical-slot radiators integrated with microstrip-line structures, specifically optimized for 28 GHz operation. The performance of the proposed mm-wave MIMO configuration is validated through simulation of its S-parameters using CST software and measurements obtained with a vector network analyzer (VNA). The proposed antenna demonstrates excellent S-parameter performance, achieving a gain of up to 6 dBi and a radiation efficiency of 94% across the operational frequency band. Each antenna element exhibits an impressive wide operating bandwidth of 9 GHz, spanning from 22.2 to 31.4 GHz at a − 10 dB threshold. Evaluations of the MIMO system's performance indicate promising results, including an exceptionally low envelope correlation of about 10 - 5 and a diversity gain of around 10 dB throughout the operating bandwidth. The design also ensures significant isolation between MIMO elements without requiring decoupling structures. A physical prototype of the proposed antenna is fabricated and subjected to measurements, depicting a strong corelation between the measured and simulated data, with some minor variations attributed to fabrication tolerances and cable losses. Comparative analysis further emphasizes the potential viability of the proposed MIMO antenna positioning it as a viable candidate for future compact-sized mm-wave MIMO systems. [ABSTRACT FROM AUTHOR]

Summary In this paper, a 4 × 4 MIMO (multiple‐input multiple‐output) antenna with metasurface (MS), which is composed of dual circularly polarized (CP) patch antennas, is proposed for 5G (sub‐6 GHz) applications. The MIMO antenna consists of four microstrip patch antennas. In order to improve the isolation of the MIMO antenna, parasitic elements are placed on the MS and layer of patch antennas. In addition, a substrate‐integrated waveguide (SIW) structure is used at the center of the MIMO antenna for this purpose. The proposed MIMO antenna is fabricated for validation tests. The antenna has overall dimensions of 115 mm × 115 mm × 3.2 mm (1.219 λ0$$ {\lambda}_0 $$ × 1.219 λ0$$ {\lambda}_0 $$ × 0.033 λ0$$ {\lambda}_0 $$, where λ0$$ {\lambda}_0 $$ is the free space wavelength at the lowest operating frequency in 10‐dB impedance bandwidth). The MIMO antenna has 10‐dB impedance bandwidth (IBW) from 3.3 to 3.8 GHz (14.08%), 3‐dB axial ratio bandwidth (ARBW) from 3.42 to 3.69 GHz (7.59%), and 6.36‐dBi peak gain. The isolation is greater than 28.14 dB in the n78 frequency band (3.3–3.8 GHz). [ABSTRACT FROM AUTHOR]

This paper presents an antenna-in-package (AiP) design realised with the conventional multi-layer printed circuit board manufacturing method. The design consists of a wideband 2 × 2 magneto-electric dipole array antenna operating from 24.25 − 29.5 GHz and a wideband transition from the analogue beamformer integrated into the proposed MED array antenna (IMED). The IMED array antenna has been fabricated with two distinct NXP analogue beamformer chips, i.e., MMW 9004 KC and MMW 9002 KC covering the N257 and the N258 band, respectively. The measured effective isotropic radiated power at P1dB was 35.3 dBm and 35.1 dBm for the IMED with the MMW 9004 KC and the MMW 9002 KC analogue beamformer chip, respectively. Our proposed antenna demonstrates the feasibility of designing a single wideband AiP that can be integrated with different analogue beamformers operating within the frequency band of the proposed antenna. This is true, provided the RFIC used for integration has the same footprint for RF ports, serial peripheral interface control ports, and DC power supply ports. The primary benefit of the proposed technique is the design antenna can adapt the operating frequency to different frequency standards by incorporating additional analogue chips without increasing the design complexity. This feature enables the antenna manufacturer to tailor the antenna products to different frequency standardisations depending on where the antenna will be employed. The AiP operates at 5G millimeter-wave (mmWave) frequencies, with the potential for Internet of Things applications. Furthermore, from our simulation results, the proposed IMED can potentially be extended as a phased array antenna with 2D scanning. [ABSTRACT FROM AUTHOR]

Handover (HO) management in Heterogeneous Networks (HetNets) poses challenges arising from network densification and dynamic environmental behaviors. Existing HO decision algorithms struggle to efficiently utilize network resources and ensure a high-quality user experience amidst the complexity of HetNets and the burgeoning growth of mobile users. This paper introduces a robust and data-driven HO decision model designed to enhance HO performance in HetNets. Initially, a conventional HO decision algorithm is developed based on users' Reference Signal Received Power (RSRP) values in MATLAB. Various simulation cases explore different HO parameters to observe their impact on handover performance. To address these challenges, a data-driven HO decision model leveraging Long Short-Term Memory (LSTM), a deep learning technique, is proposed for the regression task. The LSTM model is trained and tested using obtained RSRP values, and the future RSRP values predicted by the model are employed to trigger HO decisions in the proposed algorithm. Results from the traditional HO decision algorithm are compared with those of the proposed machine learning-based approach across various simulation runs, considering average Signal-to-Interference-plus-Noise Ratio (SINR), RSRP, user throughput values, the number of HOs and the Radio Link Failure (RLF) ratio. Different user speeds are also considered to establish a relationship between HO frequency and mobile user speed. The proposed model achieved reducing the rate of radio link failure to levels that are deemed acceptable in order to ensure a continuous connection.

A small MIMO antenna for use in dual bands is designed, simulated, and implemented in this work. Initially, a patch antenna was constructed and simulated, with further adjustments made to its size to achieve a dual-band performance at frequencies of 4.8 GHz and 6.8 GHz. A MIMO structure consisting of two elements is designedwith a partial ground plane. The electrical dimension of the antenna is 0.079λ × 0.0382λ at 4.8 GHz. The findings indicate that the MIMO antenna design demonstrated effective performance across intended frequency bands with 10 dB impedance bandwidth. The antenna displayed an essentially omnidirectional radiation pattern and achieved a satisfactory level of gain up to 5 dBi. The obtained findings exhibit promise, therefore establishing the suggested antenna as a viable option for 5G applications. The designed antenna is manufactured and practically tested in order to evaluate it's fundamental characteristics, including reflection coefficient and radiation pattern. These experimental findings were then compared to the outcomes obtained through simulation, resulting in a satisfactory consensus between simulated and measured results. [ABSTRACT FROM AUTHOR]

Printed antenna technology gained has become centre of attraction for designing MIMO antenna system for future communication applications. Antenna is an essential component for 5G communication system. MIMO technology is highly preferrable due to high data rate and simultaneous data transmission establishment. In this article, a curved slot incorporated circular shaped antenna is constructed and tested for performance utilizing conventional ground planes in an eventual Fifth Generation (5G) mobile communication network. The proposed single element system is operating from 2.6 to 12.9 GHz with an 85.84% efficiency throughout the band. The substrate of the radiator is 30 mm 30 mm 1.6 mm, where a circular patch is used whose size is 9.35 mm. A partial ground structure of 30 mm 10 mm is used to obtain high efficiency and wide bandwidth. The structured antenna system has a maximum directivity of 4.8, efficiency of 89%, and maximum gain of 1.68 dB which are desired in any MIMO system to tolerate interference and maintain user bandwidth. The proposed micro strip patch two element antenna covers 10 dB return loss frequencies from 2.6 GHz to 11.8 GHz than the conventional method. The total size of the MIMO antenna system is 70 mm 60 mm 1.6 mm. The 2-element MIMO antenna simulated results are determined by the HFSS software with their performance. [ABSTRACT FROM AUTHOR]

A T and Inverted T slotted antenna is proposed with a very compact size of (3,00 x 1,72 x 0,08) mm³. The radiator is built over FR-4 substrate. The system operates from 15 to 35 GHz attaining a very high bandwidth of 20GHz. The impedance match is observed to be high which reflects the resonances at 18.88; 21.1; 24.7; 28.0; 30.8 and 34.1 GHz with minimum reflection as – 19.6 db to a maximum of 48db. Antenna parameters such as Gain above 3dbi as a minimum and to the maximum of 10dbi is observed throughout the operating frequency. VSWR is maintained below 2 with efficiency varying within 60%. Defected Ground Structures is implemented to obtain improved gain through the operating band. The resonance points cover the bands suggested by the International Telecommunication Union for the implementation of the 5G spectrum such as n 257 and n258 bands (26.50-29.50GHz, wheres 15GHz comes under ku,k, and Q bands. Usage of these bands improves the data rate and reduces signal distortion. Through the entire performance, the antenna becomes a good candidate for 5G applications. [ABSTRACT FROM AUTHOR]

Handover (HO) management in Heterogeneous Networks (HetNets) poses challenges arising from network densification and dynamic environmental behaviors. Existing HO decision algorithms struggle to efficiently utilize network resources and ensure a high-quality user experience amidst the complexity of HetNets and the burgeoning growth of mobile users. This paper introduces a robust and data-driven HO decision model designed to enhance HO performance in HetNets. Initially, a conventional HO decision algorithm is developed based on users' Reference Signal Received Power (RSRP) values in MATLAB. Various simulation cases explore different HO parameters to observe their impact on handover performance. To address these challenges, a data-driven HO decision model leveraging Long Short-Term Memory (LSTM), a deep learning technique, is proposed for the regression task. The LSTM model is trained and tested using obtained RSRP values, and the future RSRP values predicted by the model are employed to trigger HO decisions in the proposed algorithm. Results from the traditional HO decision algorithm are compared with those of the proposed machine learning-based approach across various simulation runs, considering average Signal-to-Interference-plus-Noise Ratio (SINR), RSRP, user throughput values, the number of HOs and the Radio Link Failure (RLF) ratio. Different user speeds are also considered to establish a relationship between HO frequency and mobile user speed. The proposed model achieved reducing the rate of radio link failure to levels that are deemed acceptable in order to ensure a continuous connection. • HO management in HetNets is challenging due to network densification and dynamic environmental behaviors. • Existing HO decision algorithms are unable to efficiently ensure a high-quality user experience in HetNets. • The paper introduces a robust and data-driven HO decision model aimed at improving HO performance in HetNets. • To address the limitations of the traditional approach, a data-driven HO decision model is proposed based on LSTM. • The proposed algorithm's advantages and disadvantages are assessed based on the simulation results. [ABSTRACT FROM AUTHOR]

The rapid growth of the massive smart Internet of Things (IoT) with mobile connections, the enhanced Mobile Broadband (eMBB) and the high demand for building a connected and intelligent world increase the probability of mobile satellite systems to be a major network in providing internet communication services in the future. Currently, the mobile satellite systems are envisioned as a significant solution for providing mobile services in different settings and for various vital objectives. These satellite systems have special qualities in each of these situations, including extensive coverage area, robustness, and ability to broadcast/multicast. The Low Earth Orbit (LEO) systems are the best promising technology that will offer internet services among the different types of satellite systems. However, the LEO systems are still experiencing certain restrictions with respect to connectivity, stability, and mobility support; because of which communication becomes unreliable. Therefore, the aim of this paper is to broadly explain the LEO systems and services in a comprehensive manner using a variety of perspectives. The paper focus is on key aspects of mobile internet based on satellite systems. This paper illustrates the integration of LEO systems with fifth and sixth generations of mobile cellular networks as well as with the IoT networks. It discusses the problems being faced as a result of the integration between cellular with IoT and satellite systems by comprehending which future research plans are outlined.

In the context of fifth generation (5G) technology, Device-to-Device (D2D) communication plays a pivotal role, requiring swift and intelligent decision-making in mode selection and device discovery. This study addresses the challenge of rapid mode selection and device discovery within 5G communication networks, focusing specifically on enhancing spectral and energy efficiency for Internet of Things (IoT) applications. A novel self-centered game theory-based algorithm is introduced to optimize spectral efficiency and support intelligent mode selection. Additionally, the utilization of the support vector machine (SVM) expedites mode selection decisions. For D2D discovery, the Frank-Wolfe method is adopted, significantly improving the differentiation between D2D and Cellular users based on signal strength and interference, thereby enhancing spectral efficiency. The proposed approach maximizes spectral efficiency while adhering to strict power and interference constraints, intelligently partitioning bandwidth into two subparts using game theoretic principles to amplify spectral efficiency. Furthermore, the emphasis on energy efficiency is underscored through iterative calculations to achieve maximum energy-efficient spectral allocation. Numerical analyses validate the efficacy of the proposed technique, revealing substantial improvements in accurately predicted labels. As the number of devices increases, precision and recall rates experience noteworthy enhancements, ultimately leading to superior bandwidth utilization. This research presents a significant contribution to the field of 5G communication, particularly concerning energy efficiency, which is paramount for IoT applications. By accelerating D2D connectivity and optimizing energy and spectrum resources, it advances the goals of energy-efficient D2D communication within 5G-IoT networks. [ABSTRACT FROM AUTHOR]

The development of radio frequency circuits is currently guided mainly through two objectives, which are size reduction and performance improvement of devices. Within a reception or transmission channel, the division and/or combination of power are the most delicate stages due to their large dimensions and high insertion losses, particularly in the case of dividers/combiners based on planar technologies. In this context, this study proposes an analysis and design of a new broadband power divider and combiner using stepped impedance. The power divider/combiner developed is designed to cover a broad frequency spectrum ranging from 1 GHz to 4 GHz, including wireless applications such as Global Mobile Communications Systems (GSM), Industrial, Scientific and Medical (ISM), and Sub-6 GHz 5th Generation (5G) applications. The proposed circuit was analyzed using the stepped transmission line impedance method and designed by Advanced Design System (ADS) on an Epoxy-FR4 substrate with a dielectric constant of 4.4 and a thickness of 1.58 mm. The achieved results showed excellent characteristics in terms of transmission across the input and output terminals, mismatches at all three terminals, and isolation among output terminals. A prototype was built and the measured results showed good agreement with those obtained by simulation. [ABSTRACT FROM AUTHOR]

This paper presents a novel shared-aperture smartphone antenna for sub-6 GHz and millimeter-wave (mmWave) bands. The proposed antenna module comprises a four-element mmWave patch antenna array integrated into a wideband sub-6 GHz slot antenna. The mmWave antenna covers the frequency band 26.5–29.5 GHz with isolation over 16 dB, and the sub-6 GHz antenna covers several bands on the frequency range 3.4–6.0 GHz with isolation over 15 dB. The key features in the proposed concept are that a metal part of the sub-6 GHz antenna acts as a ground plane for the mmWave antenna array, and both antennas are located solely on the metal rim enabling a full edge-to-edge screen. The antenna achieves a high total efficiency of 65–95% and −3 dB beam steering range ±40°. A prototype is manufactured, and measurements verify wideband operation and high isolation in both frequency bands. The four-element multiple-input multiple-output (MIMO) operation with the proposed shared aperture antenna is demonstrated at the sub-6 GHz band.

Fifth generation (5G) mobile communication systems have been deployed in the millimeter wave (mmWave) band. Since electromagnetic (EM) waves in this band exhibit high propagation loss and antennas are highly directive, the performance of wireless communications is largely degraded in a non-line-of-sight (NLOS) area, resulting in a limited coverage area. To improve the performance and increase the coverage area, a metamaterial-based electromagnetic scattering sheet (EMSS) with broad scattering characteristics is proposed in this paper. We also introduce fast design and optimization methods using equivalent circuits of metamaterials, antenna array theory, and the genetic algorithm (GA). The diffusion coefficient is used as a fitness value to evaluate the scattering characteristics of the EMSS generated by GA. The broad scattering characteristics of the designed EMSS are experimentally confirmed. We clarified that the optimized EMSS has a higher diffusion coefficient than a metal plate of the same size. Finally, we demonstrated improved wireless communication performance in an NLOS area by diffusing the incoming EM fields using our designed EMSS.

Abstract With the increasing user density of wireless networks, various user partitioning techniques or algorithms segregate users into smaller, more manageable clusters. The benefit of user clustering techniques in non-orthogonal multiple access (NOMA) is to optimize resource allocation and improve network performance, spectral efficiency, and user fairness in next-generation wireless networks, particularly in scenarios with a high density of users and diverse channel conditions. With increasing users, the network creates clusters before implementing non-orthogonal multiple access within these clusters. In this paper, we have organized and classified various user clustering techniques deployed from the perspective of NOMA-based communication in the current era. Furthermore, researchers have highlighted some works deploying joint resource allocation and clustering optimization based on various criteria to enhance the overall sum rate of the network. We also identify low-complexity user clustering techniques for multiple applications, e.g. the Internet of Things, unmanned aerial vehicles, and reconfigurable intelligent surfaces in the 5G and beyond communication networks.

With the increasing user density of wireless networks, various user partitioning techniques or algorithms segregate users into smaller, more manageable clusters. The benefit of user clustering techniques in non-orthogonal multiple access (NOMA) is to optimize resource allocation and improve network performance, spectral efficiency, and user fairness in next-generation wireless networks, particularly in scenarios with a high density of users and diverse channel conditions. With increasing users, the network creates clusters before implementing non-orthogonal multiple access within these clusters. In this paper, we have organized and classified various user clustering techniques deployed from the perspective of NOMA-based communication in the current era. Furthermore, researchers have highlighted some works deploying joint resource allocation and clustering optimization based on various criteria to enhance the overall sum rate of the network. We also identify low-complexity user clustering techniques for multiple applications, e.g. the Internet of Things, unmanned aerial vehicles, and reconfigurable intelligent surfaces in the 5G and beyond communication networks. [ABSTRACT FROM AUTHOR]

This article presents a 4-way 2-D butler matrix (BM)-based beamforming network (BFN) using a multilayer substrate broadside coupled stripline (BCS). To achieve the characteristics of a compact, wide-bandwidth, high-gain phased array, a BCS coupler is implemented using the Megtron 6 substrate. The compact 2-D BFN is formed by combining planarly two horizontal BCS couplers and two vertical BCS couplers. The BFN is proposed without a crossover and without a phase shifter, generating phase responses of ±90° in the x- and y-directions, respectively. The proposed BFN exhibits a wide operating band of 66.7% (3–7 GHz) and a compact physical area of just 0.25 λ0 × 0.25 λ0 × 0.04 λ0. The planar 2-D BFN is easily integrated with the patch antenna radiation elements to construct a 2-D multibeam array antenna that generates four fixed beams, one in each quadrant, at an elevation angle of 30° from the broadside to the array axis when the element separation is 0.6 λ0. The physical area of the 2-D multibeam array antenna is just 0.8 λ0 × 0.8 λ0 × 0.04 λ0. The prototypes of the BCS coupler, the 2-D BFN, and the 2-D multibeam array antenna were fabricated and measured. The measured and simulated results were in good agreement. A gain of 9.1 to 9.9 dBi was measured. [ABSTRACT FROM AUTHOR]

This paper presents the design of a low-noise amplifier (LNA) with a bypass mode for the n77/79 bands in 5G New Radio (NR). The proposed LNA integrates internal matching networks for both input and output, combining two LNAs for the n77 and n79 bands into a single chip. Additionally, a bypass mode is integrated to accommodate the flexible operation of the receiving system in response to varying input signal levels. For each frequency band, we designed a low-noise amplifier for the n77 band to expand the bandwidth to 900 MHz (3.3 GHz to 4.2 GHz) using resistive–capacitance (RC) feedback and series inductive-peaking techniques. For the n79 band, only the RC feedback technique was employed to optimize the performance of the LNA for its 600 MHz bandwidth (4.4 GHz to 5.0 GHz). Because wideband techniques can lead to a trade-off between gain and noise, causing potential degradation in noise performance, appropriate bandwidth design becomes crucial. The designed n77 band low-noise amplifier achieved a simulated gain of 22.6 dB and a noise figure of 1.7 dB. Similarly, the n79 band exhibited a gain of 21.1 dB and a noise figure of 1.5 dB with a current consumption of 10 mA at a 1.2 supply voltage. The bypass mode was designed with S21 of −3.7 dB and −5.0 dB for n77 and n79, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a dual‐band multiple‐input multiple‐output (MIMO) antenna pair for 5G cell phones. The antenna pair consists of two planar concave antenna elements that are tightly arranged on a vertical substrate. By adding capacitors to form a resonant network, an additional operating mode is excited, resulting in dual‐band performance. The resonant frequency of the additional mode can be adjusted independently by changing the capacitance value. Moreover, a neutralization line is used to improve the isolation of the high band without affecting the low band. The antenna pair occupies a small area of 13.2 × 6.3 mm2 and operates at both 3.5 and 4.85 GHz bands. The isolations are better than 17 dB at the 3.5 GHz band and better than 19 dB at the 4.85 GHz band. The proposed dual‐band antenna pair might be a good choice for 5G terminals. [ABSTRACT FROM AUTHOR]

A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed for millimeter-wave communication systems in this paper. The multiple-input-multiple-output (MIMO) antenna geometry consists of a slotted ellipse enclosed within a hollow circle which is orthogonally rotated with a connected partial ground at the back. The overall size of the four elements MIMO antenna is 2.24λ x 2.24λ (at 27.12GHz). The prototype of four-element MIMO resonator is designed and printed using Rogers RTDuroid 5880 with εr = 2.2 and loss tangent = 0.0009 and having a thickness of 0.8 mm. It covers dual-band having a fractional bandwidth of 15.7% (27.12-31.34 GHz) and 4.2% (37.21-38.81 GHz) for millimeter-wave applications with a gain of more than 4 dBi at both bands. The proposed antenna analysis in terms of MIMO diversity parameters (Envelope Correlation Coefficient (ECC) and Diversity Gain (DG)) is also carried out. The experimental result in terms of reflection coefficient, radiation pattern, gain and MIMO diversity parameter correlates very well with the simulated ones that show the potential of the proposed design for MIMO applications at millimeter-wave frequencies. [ABSTRACT FROM AUTHOR]

A Substrate Integrated Waveguide (SIW) antenna has been presented here with a single element, which could be effectively tuned betwixt 28 and 38 GHz. By turning off one of the two PIN diodes, which were utilized as switches, a change is achieved in the antenna's resonant frequency as of 28–38 GHz. Additionally, two separate frequencies will be obtained whilst flipping both switches off. In the antenna design, there is sufficient gain along with efficiency to gratify 5G requirements. This could be accomplished by altering the antenna's SIW layout. An inset curvature has been featured by both the ends betwixt the tapered section and the SIW cavity, which alters the structure. As a result of the tapered section, superior impedance matching is achieved. A wide range of possible configurations has been offered by this reconfigurable SIW antenna by utilizing the Roger 5880 substrate along with a K-type connector input. The antenna responds with 7.16 dBi of gain and 94% efficiency at 28 GHz when S1 is disabled and S2 is enabled. Similarly, the antenna responds with a gain of 10 dBi and an efficiency of 88% at 38 GHz when S1 is on and S2 is off. When every PIN diode are turned off, the antenna enhances by 7.09 dBi for 28 GHz whereas it improves by 10.7 dBi for 38 GHz. To run the simulations, the CST Studio Suite was utilized; subsequently, the outcomes obtained are in good agreement with the predictions made by the program. [ABSTRACT FROM AUTHOR]

This paper proposes an eight-element dual-band multiple-input multiple-output (MIMO) antenna that operates in the fifth generation (5G), n78 (3400–3600 MHz), and WLAN (5275–5850 MHz) bands to accommodate the usage scenarios of 5G mobile phones. The eight antenna elements are printed on two long frames, which significantly reduce the usage of the internal space of the mobile phone. Each antenna element is printed on both surfaces of one frame, which consists of a radiator on the internal surface and a defected ground plane on the outer surface. The radiator is a rectangular ring fed by a 50 Ω microstrip line which is printed on the top surface of the system board. A parasitic unit is printed on the outer surface of each frame, which is composed of an inverted H-shaped and four L-shaped patches. Each parasitic unit is connected to the internal surface of the frames through a via, and then it is connected to a 1.5 mm wide microstrip line on the top surface of the system board, which is connected to the ground plane on the bottom surface of the system board by a via. Four L-shaped slots, four rectangular slots, and four U-shaped slots are etched onto the system board, which provides good isolation between the antenna elements. Two merged rectangular rings are printed on the center of each frame, which improves the isolation further. The return loss is better than 6 dB, and the isolation between the units is better than 15 dB in the required working frequency bands. In addition, the use of a defected ground structure not only makes the antenna element obtain better isolation but also improves the overall working efficiency. The measurement results show that the proposed MIMO antenna structure can be an ideal solution for 5G and WLAN applications. [ABSTRACT FROM AUTHOR]

Abstract The development of radio frequency circuits is currently guided mainly through two objectives, which are size reduction and performance improvement of devices. Within a reception or transmission channel, the division and/or combination of power are the most delicate stages due to their large dimensions and high insertion losses, particularly in the case of dividers/combiners based on planar technologies. In this context, this study proposes an analysis and design of a new broadband power divider and combiner using stepped impedance. The power divider/combiner developed is designed to cover a broad frequency spectrum ranging from 1 GHz to 4 GHz, including wireless applications such as Global Mobile Communications Systems (GSM), Industrial, Scientific and Medical (ISM), and Sub-6 GHz 5th Generation (5G) applications. The proposed circuit was analyzed using the stepped transmission line impedance method and designed by Advanced Design System (ADS) on an Epoxy-FR4 substrate with a dielectric constant of 4.4 and a thickness of 1.58 mm. The achieved results showed excellent characteristics in terms of transmission across the input and output terminals, mismatches at all three terminals, and isolation among output terminals. A prototype was built and the measured results showed good agreement with those obtained by simulation.

In a wireless communication chain, filters play a critical role in ensuring the efficiency, reliability, and overall performance of the system. In fact, filters are essential for selecting specific frequency bands. They can narrow or widen the bandwidth, depending on the requirements of the communication protocol. Appropriate bandwidth management is crucial for optimizing data transmission rates and accommodating multiple channels within the available spectrum. This article describes the design of a compact bandpass filter with two identical rectangular open-loop resonators. The proposed filter frequency response covers the 3.5 GHz global interoperability for microwave access (WiMAX) and fifth generation (5G) applications. The structure of this filter uses the Rogers RO6010 substrate, which has a dielectric constant of 10.2, thickness of 1.27 mm, and tangent loss of 0.0023. The proposed device is intended for wireless communication systems operating at 3.5 GHz. The filter offers a wide bandwidth of 1.21 GHz with a small size of (5.72 × 12.34) mm2, and a low insertion loss of −0.16 dB. The suggested filter offers effective utilization across various applications including fifth-generation (5G), sub-6G, and WiMAX. Simulation and optimization of the proposed design are conducted utilizing the HFSS (High Frequency Structure Simulator) software. To corroborate the results from HFSS, the ADS (Advanced Design System) software is employed. The simulation outcomes obtained from both HFSS and ADS simulators demonstrate close resemblance.

Smart Hospital will play a key role in improving the quality of services (QoS) related to the health sector. In the present scenario, it is impossible to accommodate an ageing population with the current infrastructure and facilities provided by conventional hospitals. However, the integration of technologies with the conventional hospital is enhancing the medical services and also making it easier for the public, who can save time and money by getting all the necessary medical facilities while sitting at home. The deployment of the fifth generation (5G) is taking place all over the world. The 5G network offers a better service that can be used in hospitals to make it a smart health service provider with online facilities such as video monitoring, suggesting a proper medical prescription based on medical data, remote surgery, and so on. High bandwidth, a fast data rate, low latency, and a low peak-to-average power ratio (PAPR) are some requirements that need to be fulfilled by the 5G radio. In this work, we focus on improving the power savings, spectral access, latency, and Bit error rate (BER) of the advanced 5G waveforms such as non-orthogonal multiple access (NOMA), filter bank multi carrier (FBMC), and orthogonal frequency division multiplexing (OFDM). In the first part of the article, we proposed a PAPR reduction algorithm to improve the power efficiency of the power amplifier (PA) for 5G waveforms. Several algorithms are applied to the 5G waveforms, and their performances are estimated in terms of PAPR curves. In the second part, we have utilised advanced detection algorithms to improve the signal detection of the 5G waveforms. The simulation results reveal that the proposed algorithms efficiently enhance the throughput of the framework. In the third part, we improve the spectral efficiency of the 5G waveforms by applying spectrum sensing (SS) algorithms. It is seen that the SS methods efficiently reduce the spectrum leakage of the multi-carrier waveforms (MCW). Finally, we examined the role and challenges of the Internet of Things (IoT) and artificial intelligence (AI) in smart hospitals. Overall, it is concluded that hospitals can become more effective, cut expenses, and provide better patient care with the aid of AI and IoT. Hospitals can improve patient outcomes and the state of the healthcare system as a whole by utilising these technologies.

Fifth generation (5G) applications like Internet of Things (IoT), Enhanced Mobile Broadband (eMBB), Cognitive Radios (CR), Vehicle to Vehicle (V2V) and Machine to Machine (M2M) communication put new demands on the network in terms of low latency, ultra-reliable communication and efficiency when transmitting very small bursts. One new contender that makes its appearance recently is the Universal Filtered Multi- Carrier (UFMC). UFMC is a potential candidate to meet the requirements of 5G upcoming applications. This related waveform encounters the peak-to-average power ratio (PAPR) issue arising from the usage of multi-carrier transmission. In this investigation, two PAPR reduction techniques, called Per Subband Tone Reservation (PSTR) scheme to alleviate PAPR in UFMC systems are suggested. The first one is a pre-filtering PSTR scheme that uses the least squares approximation (LSA) algorithm to calculate the optimization factor(μ) and the second one is a post-filtering method. The concept of this proposal lies on the use of peaks reductions Tone to carry the correctional signal that reduces the high peaks of each sub-band individually. To shed light on UFMC as a potential waveform for 5G upcoming application, a comparison with OFDM modulation is done.

This work presents a hybrid ring-mesh topology based passive optical network with free space optics (PON/FSO) model for bidirectional transmission at 10 × 10/10Gbps throughput to offer information to the fiber-FSO subscribers simultaneously with enhanced disaster resilience and fault protection capability. Fiber impairments, FSO link weather and turbulent conditions' tolerance can be enhanced by using a new two-dimensional modified fixed right shifting (2D-MFRS) code for upstream and downstream transmission through integrated fiber-FSO links. A PON/FSO model using 2D-MFRS code is a promising network that raises the network reliability, security and survivability, especially in rural places where the core fibre link may be damaged or destroyed. The obtained numerical and simulation results show that proposed model provides 90–130 km fiber range with fixed 100 m FSO range. FSO range of 850–1900 m with fixed 10 km fiber length can be obtained concerning weak-to-strong turbulent as well as distinct weather conditions. Also, hybrid ring-mesh topology is able to sustain −11 to −18dBm receiver sensitivities in wired-wireless transmission. The proposed model is also capable to handle 130 to 160 subscribers at symmetric 50Gbps/channel throughput. At acceptable bit error rate, low power penalty of 1 dB and −24 dB power budget are observed between back-to-back and integrated fiber-FSO link. Additionally, high signal to noise ratio of 95 dB can be maintained effectively by the system supporting 10 optical units per remote node and it also shows successful transmission upto 1:64 split ratio. Finally, the comparative literature work reveals that the proposed model offers security, long-reach, high transmission rate, and cost-effectiveness for fifth generation fronthaul/backhaul networks. [ABSTRACT FROM AUTHOR]

Smart Hospital will play a key role in improving the quality of services (QoS) related to the health sector. In the present scenario, it is impossible to accommodate an ageing population with the current infrastructure and facilities provided by conventional hospitals. However, the integration of technologies with the conventional hospital is enhancing the medical services and also making it easier for the public, who can save time and money by getting all the necessary medical facilities while sitting at home. The deployment of the fifth generation (5G) is taking place all over the world. The 5G network offers a better service that can be used in hospitals to make it a smart health service provider with online facilities such as video monitoring, suggesting a proper medical prescription based on medical data, remote surgery, and so on. High bandwidth, a fast data rate, low latency, and a low peak-to-average power ratio (PAPR) are some requirements that need to be fulfilled by the 5G radio. In this work, we focus on improving the power savings, spectral access, latency, and Bit error rate (BER) of the advanced 5G waveforms such as non-orthogonal multiple access (NOMA), filter bank multi carrier (FBMC), and orthogonal frequency division multiplexing (OFDM). In the first part of the article, we proposed a PAPR reduction algorithm to improve the power efficiency of the power amplifier (PA) for 5G waveforms. Several algorithms are applied to the 5G waveforms, and their performances are estimated in terms of PAPR curves. In the second part, we have utilised advanced detection algorithms to improve the signal detection of the 5G waveforms. The simulation results reveal that the proposed algorithms efficiently enhance the throughput of the framework. In the third part, we improve the spectral efficiency of the 5G waveforms by applying spectrum sensing (SS) algorithms. It is seen that the SS methods efficiently reduce the spectrum leakage of the multi-carrier waveforms (MCW). Finally, we examined the role and challenges of the Internet of Things (IoT) and artificial intelligence (AI) in smart hospitals. Overall, it is concluded that hospitals can become more effective, cut expenses, and provide better patient care with the aid of AI and IoT. Hospitals can improve patient outcomes and the state of the healthcare system as a whole by utilising these technologies. [ABSTRACT FROM AUTHOR]

This article describes a fractal-based MIMO antenna for 5G mm-wave mobile applications with micro-strip feeding. The proposed structure is a fractal-based spherical configuration that incorporates spherical slots of different iterations on the patch, as well as rectangular slots on the ground plane. These additions are meant to reduce patch isolation. The two-element MIMO antenna has closely spaced antenna elements that resonate at multiple frequencies, 9.5 GHz, 11.1 GHz, 13.4 GHz, 15.8 GHz, 21.1 GHz, and 26.6 GHz, in the frequency range of 8 to 28 GHz. The antenna's broadest operational frequency range spans from 17.7 GHz to 28 GHz, encompassing a bandwidth of 10,300 MHz. Consequently, it is well-suited for utilization within the millimeter wave (mm wave) application, specifically for the 5G new radio frequency band n258, and partially covers some other bands X (8.9–9.9 GHz, 10.4–11.4 GHz), and Ku (13.1–13.7 GHz, 15.4–16.2 GHz). All the resonating bands have isolation levels below the acceptable range of (|S12| > −16 dB). The proposed antenna utilizes a FR4 material with dimension of 28.22 mm × 44 mm. An investigation is conducted to analyze the effectiveness of parameters of the antenna, including radiation pattern, surface current distributions and S parameters. Furthermore, an examination and assessment are conducted on the efficacy of the diversity system inside the multiple input multiple output (MIMO) framework. This evaluation encompasses the analysis of key performance metrics such as the envelope correlation coefficient (ECC), diversity gain (DG), and mean effective gain (MEG). All antenna characteristics are determined to be within a suitable range for this suggested MIMO arrangement. The antenna design underwent experimental validation and the simulated outcomes were subsequently verified. [ABSTRACT FROM AUTHOR]

Rainfall has always been a concern for wireless communications systems. As 5G technology relies on high-frequency bands, it is fundamental to model and simulate the interaction of such radio waves with rainfall, as the deployment of large-scale infrastructure for 5G is highly expensive. This research presents a reformulation of the Maxwell equations for a bi-dimensional space in a transverse electric propagation mode, for a linear, inhomogeneous, and isotropic propagation medium with its magnetic and electric properties dependent on time. This reformulation was solved using the Finite Differences in Time Domain (FDTD) method with the Convolutional Perfectly Matched Layer (CPML) boundary condition. Two main frequency propagation scenarios were studied: 5 GHz (corresponding to Wi-Fi in the 802.11n standard as well as to the lowest bands of 5G) and 25 GHz (corresponding to 5G), within a 10 m × 3 m rectangular domain in air and with rain. The rainfall was simulated using a parallel Ziggurat algorithm. According to the findings, while 5 GHz waves experience scattering processes, 25 GHz waves experience substantial dispersion and attenuation throughout the domain in low- to moderate-intensity rain. [ABSTRACT FROM AUTHOR]

In the licensed shared access (LSA) spectrum-sharing scheme, the protection of the incumbent leads to degradation in the licensee's spectrum and energy efficiency. In this paper, the optimization of these two performance metrics for an LSA vertical sharing between an airport incumbent and a mobile network licensee during the period when the LSA spectrum is not available, (i.e, the incumbent is active) is examined. Considering a restriction zone of a predefined radius, a power allocation scheme for joint optimization of the energy and spectrum efficiency during the period of the incumbent's occupation of the LSA band is formulated. Specifically, for the joint optimization of the spectrum and energy efficiency, the weighted sum approach to solve the ensuing multi-objective optimization problem is adopted. Furthermore, various critical operational parameters in conjunction with the two performance metrics were investigated. The results obtained show that, with the proper selection of cell radius, eNodeB transmit power and user number per cell, the proposed system can simultaneously achieve the trade-off objective of improved spectrum and energy efficiency. [ABSTRACT FROM AUTHOR]

In this paper, a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2 × 2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabricated on Rogers RT/Duroid high-frequency substrate with a dielectric constant of 2.2, a thickness of 0.8 mm, and a loss tangent of 0.0009. The individual antenna in the array has a measured impedance bandwidth of 1.6 GHz from 27.25 to 28.85 GHz for S11 ≤ −10 dB, and the MIMO array has a gain of 7.2 dBi at 28 GHz with inter radiator isolation greater than 26 dB. The gain of the MIMO array was increased by introducing frequency-selective surface (FSS) consisting of 7 × 7 array of unit cells comprising rectangular C-shaped resonators, with one embedded inside the other with a central crisscross slotted patch. With the FSS, the gain of the MIMO array increased to 8.6 dBi at 28 GHz. The radiation from the array is directional and perpendicular to the plain of the MIMO array. Owing to the low coupling between the radiating elements in the MIMO array, its Envelope Correlation Coefficient (ECC) is less than 0.002, and its diversity gain (DG) is better than 9.99 dB in the 5G operating band centered at 28 GHz between 26.5 GHz and 29.5 GHz. [ABSTRACT FROM AUTHOR]

This research is guided to evaluate and determine various beneficial roles and substantial contributions of the Minimum mean square error (MMSE) algorithm in providing less power consumption and significant energy and spectral efficiencies for a larger number of users and massive data transfer capacity. A comparative analysis was led with the help of MATLAB simulations and numerical analysis to validate the relevances of the MMSE algorithm compared with ZF Hybrid, Kalman, MSE Fully Digital, and Analog-only precoding algorithms. Spectral efficiency was compared for all those five algorithms under a Signal-to-Noise Ratio range of 0 to 30 dB. According to the MATLAB numerical analysis and simulations, the results revealed that the spectral efficiency of the MMSE algorithm outpaced that of the other four algorithms considering analog and digital precoding schemes. For this reason, it can be concluded that the MMSE can be actively adopted and used for a large number of users without consuming considerable power or generating significant emissions. [ABSTRACT FROM AUTHOR]

A 28 GHz fully differential eight-channel beamforming IC (BFIC) with multimode operations is implemented in 65 nm CMOS technology for use in phased array transceivers. The BFIC has an adjustable gain and phase control on each channel to achieve fine beam steering and beam pattern. The BFIC has eight differential beamforming channels each consisting of the two-stage bi-directional amplifier with a precise gain control circuit, a six-bit phase shifter, a three-bit digital step attenuator, and a tuning bit for amplitude and phase variation compensation. The Tx and Rx mode overall gains of the differential eight-channel BFIC are around 11 dB and 9 dB, respectively, at 27.0–29.5 GHz. The return losses of the Tx mode and Rx mode are >10 dB at 27.0–29.5 GHz. The maximum phase of 354° with a phase resolution of 5.6° and the maximum attenuation of 31 dB, including the gain control bits with an attenuation resolution of 1 dB, is achieved at 27.0–29.5 GHz. The root mean square (RMS) phase and amplitude errors are <3.2° and <0.6 dB at 27.0–29.5 GHz, respectively. The chip size is 3.0 × 3.5 mm2, including pads, and Tx mode current consumption is 580 mA at 2.5 V supply voltage. [ABSTRACT FROM AUTHOR]

An FSS based electromagnetic (EM) shield for 5G, X-band and Ku-band indoor shielding applications is proposed in this manuscript. This shield offers a tri-band and polarization-insensitive behavior. A wide rejection bandwidth (10 dB) of atleast 1400 MHz, 3200 MHz and 1100 MHz for 5G, X and Ku-band is observed. The design incorporates meandered square loop (MSL) and slitted Jerusalem cross (SJC) provides shielding for the targeted bands while offering excellent incident wave angular stability up to 75 degrees. In addition to this, a lumped circuit model, metamaterial (MTM) characterization and finite element boundary integral equation (FEBI) investigations are also performed to evaluate and confirm the performance of the FSS. Dual meta-material characteristics are observed including ENG (epsilon-negative)/MNG (mu-negative) while achieving at least 30 dB shielding effectiveness (SE). [ABSTRACT FROM AUTHOR]