Radio Frequency Band Research Articles

Generalized Carrier Index Differential Chaos Shift Keying Based SWIPT with Conversion Noise and Path Loss-Effect

A generalized carrier index differential chaos shift keying with simultaneous wireless information and power transfer (GCI-DCSK SWIPT) scheme, is proposed, which is an improved scheme for CI-DCSK SWIPT. Compared to CI-DCSK SWIPT, GCI-DCSK SWIPT is not only more flexible in selecting both index bit number and index carrier number, but also is more practical for considering both path loss and the conversion noise generated by radio frequency (RF) band to baseband. The proposed scheme applied a time-switching manner to harvest the energy carried by the inactive carriers. Theoretical bit error rate (BER) expressions of the scheme over AWGN and multipath Rayleigh fading channels are derived, and the ratio of harvested energy to transmitted energy is derived to desecribe the probability of self-sufficiency on power supply. In addition, the frame-derived factor and the energy carried by inactive carriers are optimized to obtain better BER performance. Simulation results show that taking both path loss and conversion noise into consideration, the scheme is still self-sufficient with good BER performance. Furthermore, by adjusting the number of active carriers of GCI-DCSK SWIPT, some cases of GCI-DCSK SWIPT outperform conversion noise-aware CI-DCSK SWIPT in BER.

Modified fuzzy C-means and K-means clustering based spectrum sensing using cooperative spectrum for cognitive radio networks applications

The recent decade has seen a rapid evolution of communication technologies and standards with the ultimate goal of providing global users with seamless connectivity a data access. Conventional methods of communication have been completely replaced by state-of-the-art hand-held gadgets and portable devices that enable users to communicate at high transmission rates. However, as high-end devices and gadgets become more popular and their demand for operating frequency which is essentially the Radio Frequency (RF) band in the EM (Electro Magnetic) spectrum tends to force the limits to the higher end of the RF spectrum. Due to the limitation of RF band availability, a spectrum is constructed for the requesting user for promising solution, and a difficult task. The emerging cognitive radio networks are a set of intelligent tools and scheme of identify the vacant spots in the band through effective sensing and allocating the spectrum to the requesting users. A modified cluster-based model has been proposed as part of extensive research on spectrum sensing. In the proposed work, a two-phase clustering model in the form of modified Fuzzy C-Means (FCM), and K-Means clustering is used, in which FCM is used as a training module on the channel features. K-Means is effectively used as an unsupervised classifier model. The proposed classification model was tested in a densely populated cognitive radio network compared to standard methods such as SVM (Support Vector Machine), FCM, and K-Means. Superior performance in terms of quality metrics like 90% classification accuracy, 91% spectral utility 90% are notable findings of this research work.

Statistical channel model to characterize turbulence‐induced fluctuations in the underwater wireless optical communication links

SummaryUnderwater wireless optical communication (UWOC) turns out to be a primary sought alternative to wireless technology, which can provide high data rate, enormous bandwidth, and low deployment cost and resolve the crowded radio frequency band issues. The performance of the UWOC link is significantly affected by the turbulent ocean environment. In this paper, the different turbulence scenarios such as salinity gradients, temperature gradients, and air bubbles are considered to model the turbulent nature of the ocean environment experimentally. These turbulent conditions induce severe intensity fluctuations in the received optical signal. These intensity fluctuations are modeled stochastically, and a novel turbulence channel model is proposed, which excellently fitted with the experimental data. The conformity of the proposed model is validated by performing a goodness of fit test in terms of R2 and root mean square error (RMSE) coefficients. The results show that for all the considered turbulent scenarios, the Gaussian mixture model better approximates the experimental observations than the Weibull distribution. As the strength of the turbulence increases, the chances of link outage and the probability of bit errors increase. At a flow rate of 4 L/min, the bit error rate (BER) of 10−20, 10−14, and 10−10 is recorded under clear water, salinity, and temperature gradient channel conditions, respectively. It is observed that the air bubbles have a significant impact on the propagating optical beam in comparison to temperature and salinity‐induced turbulence. Moreover, a close agreement between the proposed model and the experimental data is also observed, which makes the proposed model more appropriate to describe the turbulent ocean environment.

A Compact MIMO Antenna for 5G NR Frequency Bands n257/n258/n261 Under Millimeter-Wave Communication

In this article, a compact, planar, 4-port ultra-wideband (UWB) multiple-input–multiple-output (MIMO) antenna is conceived for fifth-generation millimeter-wave applications. The suggested MIMO antenna architecture consists of four identical hexagonal-shaped slotted ground plane and four microstrip line feeds. The MIMO antenna's four components are arranged orthogonally to one another to provide a high level of inter-element isolation. The antenna prototype is constructed on a (12.5×12.5×0.8 mm3) Duroid 5880 substrate having a relative dielectric constant (ϵrsub) of 2.2 and loss tangent (tanδ) of 0.0009. Diversity characteristics such as envelope correlation coefficient (ECC), and diversity gain are determined to validate the proposed MIMO antenna's work qualities. The isolation is more than 18 dB, indicating that the proposed design is suitable for use as a quad-port MIMO antenna. The proposed MIMO antenna has a 30.47% impedance bandwidth throughout the frequency range of 26.7 GHz to 36.3 GHz, making it suitable for 5G New Radiofrequency bands n257/n258/n261 under Millimeter-Wave Communication. Positive correlations between the simulated and experimental findings are observed.

Broadband Optical Heterodyne Millimeter-Wave-over-Fiber Wireless Links Based on a Quantum Dash Dual-Wavelength DFB Laser

We demonstrate real-time broadband multi-Gb/s electrical RF synthesizer-free millimeter-wave (MMW) signals generation and wireless transmission at the 5G new radio (NR) frequency band of 47 GHz based on analog radio-over-fiber (A-RoF) fronthaul. This is enabled by a low noise, highly correlated, monolithic C-band semiconductor InAs/InP quantum-dash (QDash) dual-wavelength distributed feedback (DW-DFB) laser. One laser mode is encoded using 4-/6-GBaud multilevel quadrature amplitude modulation (M-QAM) (16-/32-/64-QAM) baseband data signals, the other lasing mode is used as an optical local oscillator for optical-heterodyne remote up-conversion to a MMW carrier of 47.27 GHz. Consequently, optical baseband modulated data signals with data capacity up to 36 Gb/s (6-GBaud × 64-QAM) are transmitted through back-to-back (BtB) and 25-/50-km of standard single mode fiber (SSMF) before the MMW carrier is optically synthesized remotely for free space wireless data transmission and detection over up to 9-m. The end-to-end MMW-over-fiber (MMWoF) wireless link is thoroughly characterized exhibiting promising error-vector-magnitude (EVM) and bit-error-rate (BER) values. The 4-/6-GBaud 16-QAM MMWoF wireless links achieve EVMs down to 6.32%/7.33%, 6.71%/7.78%, and 7.35%/8.91% through BtB, 25-km, and 50-km SSMF, respectively. Similarly, the EVM for 32-QAM and 64-QAM links is observed to be 5.56%/6.56% and 6.05%/6.62%, respectively. Moreover, in each case, the calculated BER is below the forward error correction (FEC) limit of 3.8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> . The results corroborate the potential and viability of the QDash DW-DFB laser as a simple, efficient and cost-effective alternative to individual laser sources for deployment in broadband photonic MMWoF fronthaul systems of 5G wireless networks.

Shortwave Diathermy: Actualization

Short wave diathermy (SWD) is a therapeutic modality that offers the body an increase in temperature, through the high frequency in electromagnetic irradiation, so as not to generate ionization to the tissues. This therapeutic modality works based on the principle that energy is transferred within the layers of deep tissues by a high frequency current and the generation of tissue heat. Therefore, there is an agitation of the molecules in response to an electric field, converting the kinetic energy into heat [1-4]. It uses radio frequency bands generally centered at 13.56MHz, 27.12MHz and 40.68MHz, with the most commonly used frequency being 27.12MHz with a corresponding wavelength of 11.6m (1.5).

An Optically Transparent Metantenna for RF Wireless Energy Harvesting

We propose a novel transparent metasurface antenna (metantenna) based on indium tin oxide (ITO) material for simultaneously achieving wireless energy harvesting (WEH) at radio frequency (RF) bands and efficient transmission of visible light. We adopt the design method of aperture-coupled metantenna to realize broadband and low-profile RF WEH. Then, we replace the conventional opaque metal material with an ITO coating with a sheet impedance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\Omega $ </tex-math></inline-formula> /sq to achieve the transparency of the proposed design. In order to obtain the balance between electrical performance and optical transmittivity (OT), we modify the metasurface structure to further improve the OT of the metantenna. The fabricated transparent metantenna shows an OT of more than 50%. A measured impedance bandwidth of 43.6% from 1.40 to 2.18 GHz is obtained to cover 2G and 3G wireless communication bands. Through designing the broadband rectifying circuit and the energy management circuit, we can obtain the maximum RF-dc efficiency of 65% and a stable dc output voltage of 3.4V, while the overall RF energy harvesting efficiency could reach 14.5% with the power input of 0 dBm. In addition, through the solar energy harvesting test, we can demonstrate the potential of the proposed design to work with solar panels for realizing efficient RF/solar hybrid energy harvesting.

CHANG-ES – XXVII. A radio/X-ray catalogue of compact sources in and around edge-on galaxies

ABSTRACT We present catalogues of discrete, compact radio sources in and around the discs of 35 edge-on galaxies in the Continuum Halos in Nearby Galaxies – an EVLA Survey. The sources were extracted using the pybdsf program at both 1.6 GHz (L band) and 6.0 GHz (C band) from matching resolution (≈3 arcsec) data. We also present catalogues of X-ray sources from Chandra data sets for 27 of the galaxies. The sources at the two radio frequency bands were positionally cross-correlated with each other, and the result cross-correlated with the X-ray sources. All catalogues are included for download with this paper. We detect a total of 2507 sources at L band and 1413 sources at C band. 75 sources have been successfully cross-correlated in both radio bands plus X-ray. Three new nuclear sources are candidates for low luminosity active galactic nuclei in NGC 3877, NGC 4192, and NGC 5792; the one in NGC 3877 also appears to be variable. We also find new nuclear sources in two companion galaxies: NGC 4435 (companion to NGC 4438) and NGC 4298 (companion to NGC 4302). We have also discovered what appears to be a foreground double star; each star has X-ray emission and there is radio emission at both L band and C band in between them. This could be a colliding wind binary system. Suggestions for follow-up studies are offered.

Plasma Oscillation Behavior and Electromagnetic Interference Shielding of Carbon Nanofibers/Conductive Polymer Metacomposites at Radarwave Frequency.

Metacomposites have attracted widespread attention due to their unique negative electromagnetic properties and stupendous applications. Although there are systems that realize metamaterial properties in low radio frequency bands, the research on the construction of polymer matrix metacomposites with negative performance in the pivotal GHz band is still undiscovered. Herein, carbon nanofiber/conductive polymer metacomposites with 3D overlapping network structures are innovatively constructed to achieve negative permittivity characteristics in the radarwave frequency range, and convenient methods for further adjusting the electromagnetic parameters is also proposed. The results show that the negative permittivity of CNFs/PANI metacomposites can be conveniently altered via adjusting PANI content. Furthermore, electromagnetic shielding has also been fully discussed as one of the most valuable applications of the metacomposites. The SET of CNFs/PANI-70 has an average value of 70dB at 4-18GHz and can reach a maximum of 80dB at 4GHz, which far exceeds the current commercial electromagnetic shielding standards. This work greatly broadens the promising application of metacomposites for perfect electromagnetic shielding, novel capacitance, and frequency selective surfaces.

Development of 3-D Wafer Level Packaging for SAW Filters Using Thin Glass Capping Technology

The introduction of 5G mobile communication created the need to support a large number of radio frequency (RF) bands. This required high performance and reduced size for microacoustic filters. Based on these requirements, a new three-dimensional wafer-level packaging (3-D WLP) solution based on the predecessors’ developed technology was presented to resolve reliability issues for surface acoustic wave (SAW) filter packages with large cavities. In the 3-D WLP, vertical interconnects were realized using through glass vias (TGVs). To enable such a process scheme, thin glass caps with TGVs were formed through laser-induced chemical etching. Then, glass capping dies were bonded on the corresponding LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (LT) device wafer to generate a cavity structure. Partial filling of the vias on the pad was used, and a metal trace was formed on the glass. Ball grid arrays (BGAs) were formed on top of the glass. Finally, an SAW filter WLP was fabricated. This glass capping packaging avoids the outgassing problem of conventional thin-film acoustic packaging at high temperatures, which would cause the contamination of the interdigital transducers (IDTs). In addition, a numerical study based on the 3-D finite element (FE) model has been conducted to analyze the reliability of the package. The built model was applied to perform parametric studies on the effects of package geometry, material properties, and the processing conditions on reliability. Based on the above studies, the optimized SAW filter WLP successfully passed the reliability test of pre-con level 3 and temperature cycling test (TCT, −40 °C ~ 125 °C).

Simultaneous wireless information and power transfer with fixed and adaptive modulation

Activating Wireless Power Transfer (WPT) in Radio-Frequency (RF) to provide on-demand energy supply to widely deployed Internet of Everything devices is a key to the next-generation energy self-sustainable 6G network. However, Simultaneous Wireless Information and Power Transfer (SWIPT) in the same RF bands is challenging. The majority of previous studies compared SWIPT performance to Gaussian signaling with an infinite alphabet, which is impossible to implement in any realistic communication system. In contrast, we study the SWIPT system in a well-known Nakagami-m wireless fading channel using practical modulation techniques with finite alphabet. The attainable rate-energy-reliability tradeoff and the corresponding rationale are revealed for fixed modulation schemes. Furthermore, an adaptive modulation-based transceiver is provided for further expanding the attainable rate-energy-reliability region based on various SWIPT performances of different modulation schemes. The modulation switching thresholds and transmit power allocation at the SWIPT transmitter and the power splitting ratios at the SWIPT receiver are jointly optimized to maximize the attainable spectrum efficiency of wireless information transfer while satisfying the WPT requirement and the instantaneous and average BER constraints. Numerical results demonstrate the SWIPT performance of various fixed modulation schemes in different fading conditions. The advantage of the adaptive modulation-based SWIPT transceiver is validated.

Design of a Highly Efficient Wideband Multi-Frequency Ambient RF Energy Harvester.

For low input radio frequency (RF) power from −35 to 5 dBm, a novel quad-band RF energy harvester (RFEH) with an improved impedance matching network (IMN) is proposed to overcome the poor conversion efficiency and limited RF power range of the ambient environment. In this research, an RF spectral survey was performed in the semi-urban region of Malaysia, and using these results, a multi-frequency highly sensitive RF energy harvester was designed to harvest energy from available frequency bands within the 0.8 GHz to 2.6 GHz frequency range. Firstly, a new IMN is implemented to improve the rectifying circuit’s efficiency in ambient conditions. Secondly, a self-complementary log-periodic higher bandwidth antenna is proposed. Finally, the design and manufacture of the proposed RF harvester’s prototype are carried out and tested to realize its output in the desired frequency bands. For an accumulative −15 dBm input RF power that is uniformly universal across the four radio frequency bands, the harvester’s calculated dc rectification efficiency is about 35 percent and reaches 52 percent at −20 dBm. Measurement in an ambient RF setting shows that the proposed harvester is able to harvest dc energy at −20 dBm up to 0.678 V.

Reconfigurable Pattern Patch Antenna for Mid-Band 5G: A Review

New requirements in communication technologies make it imperative to rehash conventional features such as reconfigurable antennas to adapt with the future adaptability advancements. This paper presents a comprehensive review of reconfigurable antennas, specifically in terms of radiation patterns for adaptation in the upcoming Fifth Generation (5G) New Radio frequency bands. They represent the key of antenna technology for materializing a high rate transmission, increased spectral and energy efficiency, reduced interference, and improved the beam steering and beam shaping, thereby land a great promise for planar antennas to boost the mid-band 5G. This review begins with an overview of the underlying principals in reconfiguring radiation patterns, followed by the presentations of the implemented innovative antenna topologies to suit particular advanced features. The various adaptation techniques of radiation pattern reconfigurable planar antennas and the understanding of its antenna design approaches has been investigated for its radiation pattern enhancement. A variety of design configurations have also been critically studied for their compatibilities to be operated in the mid-band communication systems. The review provides new insights on pattern reconfigurable antenna where such antennas are categorized as beam steering antenna and beam shaping antennas where the operation modes and purposes are clearly investigated. The review also revealed that for mid-band 5G communication, the commonly used electronic switching such as PIN diodes have sufficient isolation loss to provide the required beam performance.

Feasibility Study of a W-Band Multibeam Heterodyne Receiver for the Gregorian Focus of the Sardinia Radio Telescope

We report on the feasibility study of a W-band multibeam heterodyne receiver for the Sardinia Radio Telescope (SRT), a general purpose fully steerable 64-m diameter antenna located on the Sardinia island, Italy, managed by INAF (“Istituto Nazionale di Astrofisica,” Italy). The W-band front-end is designed for the telescope Gregorian focal plane and will detect both continuum and molecular spectral lines from astronomical sources and radio emission from the Sun in the 3 mm atmospheric window. The goal specification of the receiver is a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> focal plane array operating in dual-linear polarization with a front-end consisting of feed-horns placed in cascade with waveguide Orthomode Transducers (OMTs) and LNAs (Low Noise Amplifiers) cryogenically cooled at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx $ </tex-math></inline-formula> 20 K. The instantaneous FoV (Field of View) of the telescope is limited by the shaping of the 64-m primary and 7.9-m secondary mirrors. The cryogenic modules are designed to fit in the usable area of the focal plane and provide high-quality beam patterns with high antenna efficiency across the 70 – 116 GHz Radio Frequency (RF) band. The FoV covered by the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> array is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.15\times 2.15$ </tex-math></inline-formula> arcmin <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , unfilled, with separation between contiguous elements of 43 arcsec. Dual-sideband separation (2SB) down-conversion mixers are designed to be placed at the cryostat output and arranged in four four-pixel down-conversion modules with 4 – 12 GHz Intermediate Frequency (IF) bands (both Upper Side Band and Lower Side Band selectable for any pixel and polarization). The receiver utilizes a mechanical derotator to track the parallactic angle.

Spectral Efficiency Classification Schemes for Future Network Communications(SECS)

Abstract Future Network is an project created and managed by ISO/IEC. The project has produced technical reports in ISO/IEC TR 29181 series and is in the process setting architectures and protocols. The project is known for its distinctive “clean slate design” approach and works on fundamental structural innovations to allow Future Network deliver its promises. Simultaneously, ISO/IEC Future Network should prepare itself for future breakthrough in SE technology and make plans to adapt Future Network to the fast changing “Post Shannon Era” technological revolutions. Using reference to the mechanism of radio frequency band classifications, this standard classifies the spectral efficiencies of the MCS systems, so as to facilitate the classification, discussion, evaluation and comparison of the efficiency of the spectrum of information systems.

Моделирование полосно-пропускающих фильтров на основе многослойной технологии

One of the integral parts of modern radio transmitting devices are bandpass filters that limit the out-of-band spectrum of electromagnetic radiation and the side effect of electromagnetic radiation, which is important in the framework of the dense distribution of the radio frequency band between radio services. Similar functions of bandpass filters are made as part of radio receivers and placed at the input. At the same time, they also perform the functions of a matching device between the radio receiving connection and the antenna-feeder path. Currently, there are known methods for the development of bandpass filters based on microstrip technology, which has such advantages as: a broad theoretical base, manufacturability, a wide selection of dielectric bases, and the possibility of simulation without using expensive software. At the same time, the disadvantage of microstrip technology is the need to expand the area of dielectric bases with an increase in the number of frequency-selective elements. Currently, a promising direction in the implementation of bandpass filters is their design based on a multilayer technology, which makes it possible to increase the number of frequency-selective elements without expanding the area of dielectric bases. Purpose of the study. The purpose of this article is to study the frequency-selective properties of design options for a bandpass filter based on multilayer technology, the basic element of which is a microstrip transition. Materials and methods. For the considered designs of the bandpass filter, a numerical electrodynamics simulation was carried out in the ANSYS HFSS software with an estimate of the dependence of the S-parameters in the frequency range of 0.2–4 GHz. The graphical distribution of the electromagnetic field in the microstrip transition was obtained. Results. From the results of the simulation it follows that the considered designs of the bandpass filter are characterized by good matching with a wave impedance of 50 Ohm (VSWR no more than 1.5 in a wide frequency range), low attenuation at the center frequency (no more than 0.5 dB), and by significant suppression of a signal outside its bandwidth (more than 30 dB). Conclusion. The simulation results prove the possibility of practical application of bandpass filters, developed on the basis of multilayer technology, as part of radio transmitting devices of radar and radio navigation systems.

Development Of A Millimeter Wave Eight-Element Phased Array Antenna for 5G Mobile Communications

The fifth generation (5G) mobile communications systems demand millimeter wave (mmWave) bands of the electromagnetic spectrum beside the current sub-6 GHz frequencies. Allocation of mmWave frequencies for the cellular systems will ensure more capacity and higher speed links. For the last few years wireless communications societies in industry and academia have put significant research effort to develop novel and efficient antenna architectures. We need brand-new antenna structures that can overcome the challenges of 5G communications environment such as high propagation loss of mmWaves and the large bandwidth demand of the planned networks. In this paper, a microstrip mmWave antenna array for 5G mobile phone terminals is introduced. First, the single antenna element with the rectangular patch radiator is investigated. The numerical investigation is carried out with a full-wave electromagnetic solver. The single antenna design operates between 27.1 GHz – 28.95 GHz frequencies. The proposed antenna based on microstrip approach shows low profile characteristics without compromising performance. A maximum gain of ~7.7 dBi is achieved within the operation band. Then eight-element phased array implementation of the proposed antenna is analyzed. Uniformly spaced linear array method is used with ~λ/2 spacing in the configuration. The eight-element array boosts the maximum total gain value up to ~ 15 dBi, and yields beam steering at broadside up to ∓50° with low side lob levels (SLL). Furthermore, the proposed phased array design is compact with the dimensions of 10 mm×48.6 mm×0.51 mm, and therefore it is compatible with the mmWave band radio frequency integrated circuit (RFIC) transceivers.

Exothermic synthesis of ceramic materials based on barium and strontium aluminosilicates

Ceramic materials were synthesized in the RO(R=Ba, Sr)–Al2O3–SiO2 system using exothermic synthesis from solutions containing barium and strontium nitrates, silica and organic reducing agents (glycine and carbamide). It was shown that only the use of a mixture of glycine and carbamide as well as the addition of ammonium nitrate allows carrying out a complete exothermic synthesis with the formation of an X-ray amorphous product with a small fraction of the crystalline phase. It was established that monophase materials based on barium and strontium aluminosilicates (BaAl2Si2O8 and SrAl2Si2O8) are formed when the obtained X-ray amorphous product is heat-treated at the temperatures above 10000C. Ceramics from synthesized materials sintered at 15500C has a high refractoriness, open porosity of 0–1.0%, compressive strength of 115–120 MPa; dielectric constant of 3.25–6.0 (at the frequency of 1 MHz) and the loss tangent of (1.5–5.2)10–3. The results shows that the exothermic synthesis ensures the preparation of nano- and sub-microcrystalline powders in the system RO(R=Ba, Sr)–Al2O3–SiO2. Materials based on the obtained aluminosilicates can be used in the manufacture of protective structures for devices operating in the radio frequency band, in radar installations of aviation and rocket technology, in microwave elements, etc.

Sensing and analysis of spectrum holes in ISM band using USRP testbed

The spectrum frequency in the wireless communication industry is getting great attention due to the internet of things (IoT) technology's growth. However, the radio spectrum's frequency band use is limited because the primary user for specific services can cause spectrum interference as multiple users use the same spectrum frequency. Meanwhile, at each spectrum frequency, the number of users and utilization time are distinct. These will create vacancies for spectrum frequency assigned to the primary user. A new alternative in using the cognitive radio (CR) spectrum is accessible to these vacancies. This paper analyzed the frequency spectrum in the industrial, scientific and medical (ISM) band and identified spectrum holes for transmission by the secondary users. This work employed a realistic approach by measuring the spectrum using Universal Software Radio Peripheral (USRP) devices. Thus, the spectrum holes in the frequency spectrum had distinguished by using an energy detection technique. In the energy detection technique, the threshold energy level is set and then compared with the energy detector output to identify the primary user's existence (PU). The result indicates that 0.61% of spectrum holes have been detected in the 2.43-2.44 GHz range. This range is sufficient for home appliances, radio frequency peripherals (RF), and bluetooth devices.

Feasibility Analysis of Fifth-generation (5G) Mobile Networks for Transmission of Medical Imaging Data.

Next to higher data rates and lower latency, the upcoming fifth-generation mobile network standard will introduce a new service ecosystem. Concepts such as multi-access edge computing or network slicing will enable tailoring service level requirements to specific use-cases. In medical imaging, researchers and clinicians are currently working towards higher portability of scanners. This includes i) small scanners to be wheeled inside the hospital to the bedside and ii) conventional scanners provided via trucks to remote areas. Both use-cases introduce the need for mobile networks adhering to high safety standards and providing high data rates. These requirements could be met by fifth-generation mobile networks. In this work, we analyze the feasibility of transferring medical imaging data using the current state of development of fifth-generation mobile networks (3GPP Release 15). We demonstrate the potential of reaching 100Mbit/s upload rates using already available consumer-grade hardware. Furthermore, we show an effective average data throughput of 50Mbit/s when transferring medical images using out-of-the-box open-source software based on the Digital Imaging and Communications in Medicine (DICOM) standard. During transmissions, we sample the radio frequency bands to analyse the characteristics of the mobile radio network. Additionally, we discuss the potential of new features such as network slicing that will be introduced in forthcoming releases.