Commercial Communication Systems Research Articles

Penyerap Bahan Meta Berbilang Lapisan Padat untuk Aplikasi Frekuensi Satelit Jalur Ka

This work investigates the effects of multi-layered metamaterial design for absorption application at satellite frequency. This is because, the adopted Ka-band frequency is very useful for current technology which can be used in highresolution, close-range targeting radars, military aircraft, space telescopes, commercial, and wireless point-point microwave communication systems. Hence, this work focused on producing a compact design by adopting the optimisation method. Four square-shaped and two circular-shaped metamaterial rings were designed on 0.25 mm substrate material. Furthermore, the properties of the proposed metamaterial were discovered by adopting Computer Simulation Technology. This analytical simulation was performed for a frequency range between 27 and 40 GHz. On the other hand, several design analyses were investigated to gain an optimal metamaterial design structure for the proposed applications. For instance, unit cell selection analysis, reflection coefficient and absorbance analysis of the multi-layer metamaterial. Moreover, the proposed unit cell metamaterial manifests double resonance frequencies for reflection and transmission coefficients approximately at 27.31 GHz, 33.40 GHz and 30.56 GHz, 38.23GHz, respectively. The increment of layers on the proposed unit cell structure revealed unique responses. For example, the double multilayer metamaterial manifests similar dual resonance frequencies as the unit cell design but gains excellent magnitude values of more than -10. Moreover, the absorbance of the three distinct layer metamaterials, likely double, triple and quadruple layers were analysed as well in this work. Overall, the proposed compact metamaterial absorber exhibits unique behaviours for Ka-band satellite frequency applications.

Performance analysis of OFDM with variations in cyclic prefix and FFT lengths

Orthogonal Frequency Division Multiplexing (OFDM) is a modern and suitable modulation strategy for commercial high-speed broadband wireless communication systems. This is because wireless services and demands have grown so quickly in recent years. While creating wireless communication, the channel environment is crucial. A square grid with identical vertical and horizontal spacing is used for the constellation points in quadrature amplitude modulation (QAM). More bits can be transferred per symbol to higher-order modulation forms. This research has looked at how Orthogonal Frequency Division Multiplexing OFDM systems perform using different modulation techniques on channels with additive white Gaussian noise (AWGN). Using MATLAB software to do an experiment with different modulation methods and parameters such as FFT length and cyclic prefix findings showed that 64-QAM modulation sends the same amount of data faster and with fewer symbols than QPSK 16-QAM. Here, the 64-QAM modulation technique performs better. An extensive literature survey has been carried out. The work done here involved working on many parameters to improve the performance of OFDM, i.e., by reducing BER, changing modulation techniques, and analyzing the trade-off between cyclic prefix length and Bit Error Rate. Compared to the existing work, the proposed system provides better performance.

Digital backpropagation based on binary logarithmic step size distribution for fibre non‐linearity compensation

AbstractCapacity crunch has become critical in recent years as commercial communication systems approach their theoretical data rate limits. This work presents a low‐complexity digital backpropagation (DBP) implementation approach based on step size distribution that uses a binary logarithmic step size method to achieve high data rate optical transmission. The proposed scheme shows performance improvements (∆Q) of 2.36, 1.19, and 0.71 dB over linear compensation, constant step size (CSS) DBP, and logarithmic step size DBP techniques in a 2400 km 112 Gbit/s DP‐16 quadrature amplitude modulation (QAM) system, respectively. At 13 dBm, a high performance (Q) of 10.9 dB (BER = 2.25 × 10−4) is achieved, above the 3.80 × 10−3 hard‐decision forward error correction (HD‐FEC) limit, using the proposed scheme. Also, the allowable transmission distance is extended by 960 km at the HD‐FEC limit over the linear compensation technique. The optimization achieves a 38% saving in the number of DBP calculation steps compared to the CSS DBP, which considerably reduces the computational cost since a few steps are required for effective non‐linearity compensation.

Machine-Learning-Assisted Cyclostationary Spectral Analysis for Joint Signal Classification and Jammer Detection at the Physical Layer of Cognitive Radio.

Cognitive radio technology was introduced as a possible solution for spectrum scarcity by exploiting dynamic spectrum access. In the last two decades, most researchers focused on enabling cognitive radios for managing the spectrum. However, due to their intelligent nature, cognitive radios can scan the radio frequency environment and change their transmission parameters accordingly on-the-fly. Such capabilities make it suitable for the design of both advanced jamming and anti-jamming systems. In this context, our work presents a novel, robust algorithm for spectrum characterisation in wideband radios. The proposed algorithm considers that a wideband spectrum is sensed by a cognitive radio terminal. The wideband is constituted of different narrowband signals that could either be licit signals or signals jammed by stealthy jammers. Cyclostationary feature detection is adopted to measure the spectral correlation density function of each narrowband signal. Then, cyclic and angular frequency profiles are obtained from the spectral correlation density function, concatenated, and used as the feature sets for the artificial neural network, which characterise each narrowband signal as a licit signal with a particular modulation scheme or a signal jammed by a specific stealthy jammer. The algorithm is tested under both multi-tone and modulated stealthy jamming attacks. Results show that the classification accuracy of our novel algorithm is superior when compared with recently proposed signal classifications and jamming detection algorithms. The applications of the algorithm can be found in both commercial and military communication systems.

Implementation of explainable artificial intelligence in commercial communication systems using micro systems.

The developments in the field of artificial intelligence (AI) and decision making systems are identified as virtuous models for banking and finance sector (BFS) applications. Even though AI provides great advantage in application changes it is essential to remodel the system using explainable artificial intelligence (XAI) design system. Also the standard sensing models provides appropriate monitoring values but huge size of sensors is considered as a major drawback. Thus two diverse problems are addressed in this research work where XAI has been integrated with micro electro-mechanical systems (MEMS) for solving the problems related to BFS applications. Further the data security has been enhanced as XAI is implemented with conviction managements and real time experiments are carried out by developing a unique application by integrating new mathematical designs. To validate the effectiveness of BFS application the developed model is tested with five scenarios which includes multiple parametric arrangements with interpretability process. The tested and compared outcomes with existing models indicates that XAI and MEMS provides inordinate improvements in terms of data impairments thus increasing the transparency of the projected system to an average 96%.

Coupling receiver–transmitter metasurface-based Fabry–Pérot resonant antenna with dual circular polarization

AbstractThis study presents a dual-circularly polarized (CP) Fabry–Pérot (FP) antenna, employing a novel receiver–transmitter (RT) metasurface (MS). The RT-MS unit cell consists of two identical neighboring substrates, with a three-layer metal coating printed on their surfaces. The bottom patch is adopted as a receiver to transfer electromagnetic waves to the top-corner cut patch, passing through the coupling cross-slot sandwiched in the middle. The RT-MS has high reflectivity to achieve a high gain. Through energy and a cross-slot, high aperture efficiency can be realized. A conventional corner cut patch can excite a CP mode of equal magnitude and a 90° phase difference. The RT-MS is arranged in 12 × 12 unit cells and used as a superstrate for a dual-CP antenna. Two orthogonally etched slots fed by two branch-matched orthogonally arranged feed lines are used as feeders to produce perpendicular linearly polarized waves. To enhance the bandwidth and improve the gain, double identical stack substrate patches are placed at the top side of the slot with no air gap, for a wide impedance band and high gain. Two wide CP bands, left-hand circular polarization and right-hand circular polarization, of 12.21–13.1 GHz (7.03%) and 12.35–13.1 GHz (5.89%), respectively, have maximum high gains of 16.5 and 15.97 dBic at 12.58 and 12.7 GHz, respectively, with a compact size of 2.6λ0 × 2.6λ0, suggesting better properties than recent antennas. The aperture efficiency can reach 63.2%. Thus, the RT-MS-based FP antenna is a good candidate for commercial and military communication systems.

Complementary Metal Oxide Semiconductor Digitally Controlled Passive Phase Shifter Circuit for Bearing Angle Control in Multiple Antenna System

A Complementary Metal Oxide Semiconductor (CMOS) digitally controller passive phase shifter circuit for bearing angle control in multiple antenna systems with the changes of the frequency angle or phase shift by using the passive component is presented. The circuit has been designed by using TSMC 0.18 um CMOS technology on the Advanced Design System (ADS) software. This project aims to look for multiple phase transition angles on the same circuit by using the switch in order to get different shifter pattern selectors in series with a digital phase tuning phase adapted using digital capacitors and inductors loading a lumped element transmission line. The phase shifter has a range of 360° with 5.6° resolution at 8-11 GHz frequency band. These CMOS phase shifter characteristics are attractive for multiple antennae and commercial phased array communication systems where cost, size, weight, power and high linearity are required.

Capacity expansion of chaotic secure transmission system based on coherent optical detection and space division multiplexing over multi-core fiber.

We propose and experimentally study a coherent optical chaotic secure transmission system through a multi-core fiber (MCF). The messages are encrypted by the chaotic carrier and transmitted through the outer cores of the MCF, whereas the chaotic carrier signal is concealed by transmitting through the center core. The MCF provides large transmission capacity expansion and security enhancement against eavesdroppers due to its physical structure. In addition, the designed optical chaos self-homodyne coherent detection strategy has high detection sensitivity and simple physical structure. Due to the prevalence of devices and digital signal processing (DSP) algorithms used in this system, it can be well compatible with a commercial coherent optical communication system. Error free 40 Gb/s/core encrypted 16 quadrature amplitude modulation (QAM) signal transmission over 10 km 7-core fiber is achieved, and 20 Gb/s quadrature phase shift keying (QPSK) signal transmission over a 100 km standard single-mode fiber (SSMF) is demonstrated to verify the long-distance transmission capability. The sensitivity to the secret key is also studied.

Free-Space Transmission and Detection of Variously Polarized Near-IR Beams Using Standard Communication Systems with Embedded Singular Phase Structures.

We propose to achieve multichannel information transmission in free space by means of variously polarized beams. The interaction of vortex beams of various orders with the main polarization states is theoretically analyzed. The passage of beams with different polarization states through multi-order diffractive optical elements (DOEs) is simulated numerically. Using the simulation results, tables of code correspondence of diffraction order numbers to the presence of phase vortices in the analyzed beams are constructed, which allow one to determine diffraction orders that carry information about various polarization states. The performed experiment made it possible to study the recognition of the first order cylindrical polarization state formed by a Q-plate converter using a phase DOE. In the experiment, these elements were built into a commercial fiber-optic communication system operating at the near-IR frequencies. After detecting the beam polarization state, beams of the required diffraction orders are efficiently coupled into optical fiber using an additional phase element. The developed optical detection system also provides channel suppression of homogeneously polarized components, which are supposed to be used for transmission of other channels.

Regulation and Business in the Origins and Development of the Mass Media: Radio Broadcasting in Spain

Wireless telegraphy ranks as the third groundbreaking 19th-century contribution to modern telecommunications, after the electric telegraph and the telephone. Initially of little interest, it gained widespread acceptance and became a commercial communication system that was fiercely fought for by the world's major powers. One feature of radiotelegraphy is broadcasting¸ which has developed with great impetus among the economic powers. In Western Europe, state control over broadcasting predominated from the first regulation in the 1920s until the 1980s. This was the case in Spain, where the State imposed a system of concession for the construction and operation of the network of stations by public tender. Finally, the development of broadcasting was inferior to that of the major powers but superior to that of other Mediterranean nations, as indicated by the sixth position it occupied in a selected list of countries. This study is performed to analyze broadcasting penetration from a dual perspective of supply/demand and the economic and business angle, mainly from primary sources.

Metamaterial inspired pin wheel fractal shaped antenna using parasitic split ring resonator for modern wireless applications

This article presents the Pin Wheel Fractal Antenna (PWFA) loaded with Split Ring Resonator (SRR) for X-band and Ku-band wireless applications. The performance of the final iteration of the proposed PWFA has been improved with the loading of SRR in terms of reflection coefficient, bandwidth and gain. The proposed design is fed with 50 Ω microstrip line along with the quarter-wave impedance matching line. To obtain the resonance and radiation characteristics, ground plane length and width of matching line has also been optimized. The bandwidth and gain improved by 26.6% and 31.3% respectively in the first resonance (C-band) and by 16.5% and 8.1% respectively in second resonance (Ku-band) in SRR loaded structure. A prototype of the proposed PWFA is also fabricated and comparison of the simulated and measured results are found in good agreement. The overall dimension of the proposed design is 30 mm × 30 mm, which can be used for various commercial, military and mobile communication systems for C-band and Ku-band.

Effective Performance Metrics for Multimedia Mission-critical Communication Systems

Mission-critical Communication Systems that are adaptable for use with the latest generation of multimedia services are crucial for system users. To determine the set of requirements that need to be hardcoded into such systems, a clear distinction between mission-critical and non-mission-critical systems is required. Moreover, the users of services provided by such systems are very different to those of current mobile commercial communication systems. These differences give rise to a set of challenges that need addressing to facilitate migration from existing systems to those now being proposed. One such challenge relates to the performance of the IP Multimedia Subsystem (IMS) registration process. This is a crucial consideration for mission-critical systems, particularly in large-scale systems where thousands or even millions of users may seek to access the system in disaster scenarios. This paper presents an evaluation of IMS and Session Initiation Protocol (SIP) performance metrics and Key Performance Indicators (KPIs). Moreover, it articulates a proposed study that will seek to address some of the challenges identified.

АНАЛИЗ ПЕРСПЕКТИВ РАЗВИТИЯ ИСТОЧНИКОВ ОДИНОЧНЫХ ФОТОНОВ В СИСТЕМАХ КВАНТОВОГО РАСПРЕДЕЛЕНИЯ КЛЮЧЕЙ

Introduction: The analysis of the main directions of research in the field of creating sources of single photons for communication systems with quantum key distribution is carried out. Scientometric analysis based on Scopus database is used to identify the most promising areas and predict the trends in the field of single photon sources. Methods of single photon sources development and their applications in commercial communication systems with quantum key distribution is shown. At the time single photons sources based on quantum dots are the most developed and presented on the market. However, color centers in nanocrystals and carbon nanotubes are intensively studied. The prospects of creating compact and easy-to-use sources of single photons on telecommunication wavelengths is analyzed. There are many ways of realization of single photon sources design. Significant funding in China and Germany leads to notable growth of the technology. It was detected the main journals, author groups and organizations working in direction of single photon sources. Methods and Results: The research field of communication systems using sources of single photons is growing. It is available single photon sources on quantum dots and crystals. Applying of carbon nanotubes is promising for this problem according to some famous authors. It is revealed significant overlap of the research areas: single photon sources, quantum random number generators and quantum key distribution. At the time fundamental studies are implemented in technical devices with high potential for commercial applications.

An Efficient Sinusoid-Like Pseudo Random Sequence Modulator/Demodulator System With Reduced Adjacent Channel Leakage and High Rejection to Random and Systematic Interference

Emerging wireless communication services require the efficient use of available spectrum and improved co-existence of different standards placed in adjacent frequency bands. Co-existence with leakage from primary users in adjacent channels, which falls in the band of interest, is a primary concern for existing and emerging technologies. In this paper, a mixed signal IC technique based on direct sequence spread spectrum is proposed to improve co-existence of radar systems with commercial wireless communication systems. A sinusoid-like pseudo-random sequence is introduced to reduce leakage from radar systems into adjacent channels. The proposed approach reduces the radar signal leakage on adjacent channels by about 22dB when compared with the conventional binary pseudo-random sequence. The proposed technique randomizes narrow and wideband systematic in-band interference, after which interference power can be effectively attenuated through averaging techniques. Experimental results from a 40nm CMOS technology modulator/demodulator prototype demonstrates the feasibility of the proposed architecture. The modulator and demodulator system requires a silicon area of 0.0459mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consumes 4.33mW in total.

Introduction to polar earth orbits (PEO) in the function of the satellite distress and safety systems (SDSS)

&lt;p align="LEFT"&gt;In this paper is described introduction of Polar Earth Orbits (PEO) in the function of the Satellite Distress and Safety Systems (SDSS) for all mobile applications. The results of a technical and economic study regarding the extension of the Inmarsat Geostationary Earth Orbit (GEO) satellite system to cover polar region are reviewed. In addition, also are examined the technical and practical aspects of providing an operational polar Mobile Satellite Service (MSS) for the provision of combined distress and safety communication solutions in conjunction with a commercial and defense communication systems for maritime, land and aeronautical applications. This study is considered several PEO satellite models and their probable costs for Search and Rescue (SAR) and determination MSS solutions. The practical usage of Low PEO constellation is realized by Cospas-Sarsat international project for SDSS.&lt;/p&gt;

Effective Feature Selection Method for Deep Learning-Based Automatic Modulation Classification Scheme Using Higher-Order Statistics

Recently, in order to satisfy the requirements of commercial communication systems and military communication systems, automatic modulation classification (AMC) schemes have been considered. As a result, various artificial intelligence algorithms such as a deep neural network (DNN), a convolutional neural network (CNN), and a recurrent neural network (RNN) have been studied to improve the AMC performance. However, since the AMC process should be operated in real time, the computational complexity must be considered low enough. Furthermore, there is a lack of research to consider the complexity of the AMC process using the data-mining method. In this paper, we propose a correlation coefficient-based effective feature selection method that can maintain the classification performance while reducing the computational complexity of the AMC process. The proposed method calculates the correlation coefficients of second, fourth, and sixth-order cumulants with the proposed formula and selects an effective feature according to the calculated values. In the proposed method, the deep learning-based AMC method is used to measure and compare the classification performance. From the simulation results, it is indicated that the AMC performance of the proposed method is superior to the conventional methods even though it uses a small number of features.

Effective Capacity Based Power Allocation for the Coexistence of an Integrated Radar and Communication System and a Commercial Communication System

Considerable interest has been shown in the coexistence between airborne radar and commercial communication systems in recent years. In particular, the integrated radar and communication system (IRCS) is promising for the airborne platforms like Unmanned Air Vehicles (UAVs). However, due to fast varying channels caused by high mobility, it is a great challenge for the fusion center to collect detection information within a given delay threshold through the air-to-ground (A2G) communication. Based on slowly varying components of the channel, i.e, target spectrum, power spectral densities of the signal dependent clutters, path loss and shadow fading, this paper considers the problem of power minimization for an IRCS and a base station (BS) coexisting in the same frequency band. The latency bound, latency violation probability (LVP), and channel capacity for the A2G communication to the fusion center are considered based on the effective capacity (EC) theory. The detection performance for radar and the rate requirement of BS user are also taken into account. The power allocation problem is non-convex and formulated to a monotonic optimization problem. Afterward, an efficient heuristic scheduling algorithm with acceptable computational complexity is proposed to solve the formulated problem. Then, the robust power allocation with channel estimation error is considered. Simulation results demonstrate the effectiveness of the proposed heuristic algorithm from the perspectives of the total transmit power, EC, and LVP of the IRCS.

Three Decades of 3GPP Target Cell Search through 3G, 4G, and 5G

This survey provides the reader with the open literature on the detailed operational scenarios of Target Cell Search (TCS) in both 3G and 4G systems, with a particular emphasis on the DownLink (DL). There is no completely latest survey of the TCS scenarios. Therefore, we examine the TCS-involved solutions which have been chosen for Wideband-Code Division Multiple Access (W-CDMA), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), Long-Term Evolution Frequency Division Duplex (LTE-FDD), and Time-Division Long-Term Evolution (TD-LTE). Especially for TD-SCDMA, there is no concrete literature demystifying the details of TCS scenario. Accordingly, this survey aims for repairing the associated crack in the literature. Moreover, as a recent evolution from the operational systems, we also focus on the TCS scenario which can be exploited in New Radio (NR) systems operating at both sub-6 GHz and millimeter-Wave (mmW) spectrum bands. A taxonomy diagram is also provided to classify relevant target cell search scenarios in 3G, 4G, and 5G as well as followed by those in inter-Radio Access Technologies (RATs). In a nutshell, our endeavors definitize the first comprehensive survey on the TCS progress tailored to the evolution of commercial mobile communication systems over three decades. It is worth mentioning that this survey is also informative for engineers and researchers to design practical mobile station modem.

Orbital Angular Momentum Waves: Generation, Detection, and Emerging Applications

Orbital angular momentum (OAM) has aroused a widespread interest in many fields, especially in telecommunications due to its potential for unleashing new capacity in the severely congested spectrum of commercial communication systems. Beams carrying OAM have a helical phase front and a field strength with a singularity along the axial center, which can be used for information transmission, imaging and particle manipulation. The number of orthogonal OAM modes in a single beam is theoretically infinite and each mode is an element of a complete orthogonal basis that can be employed for multiplexing different signals, thus greatly improving the spectrum efficiency. In this paper, we comprehensively summarize and compare the methods for generation and detection of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications and technical challenges of OAM in communications, including free-space optical communications, optical fiber communications, radio communications and acoustic communications. To complete our survey, we also discuss the state of art of particle manipulation and target imaging with OAM beams.

Analysis on Cross-Correlation Coefficient for Survivability of Chirp Spread Spectrum Systems

Since chirp spread spectrum (CSS) system has robustness to reduce multipath fading effect and to extend spectrum bandwidth with low energy consumption, the CSS system has attracted much attention not only for radio detection and ranging systems but also for commercial wireless communication systems. In the spread-spectrum systems, low probability of detection (LPD) and anti-jamming (AJ) abilities are two key issues. In this paper, a multiple linear chirp (MLC)-based binary orthogonal keying (BOK)-CSS system considering cross-correlation coefficient for improving the LPD and the AJ performances is proposed. In order to analyze the performance of the MLC-based BOK-CSS system, the cross-correlation coefficient between two different chirps is analytically derived according to the time-bandwidth separation product, and it is numerically compared to a Monte Carlo simulation. From the results, the proposed MLC-based BOK-CSS system guarantees higher survivability than the conventional schemes by considering the cross-correlation coefficient according to the bandwidth separation.