Today's Communication Systems Research Articles

Optical matrix computing for optical forward error correction encoding

Forward error correction (FEC) has been widely used in today's communication systems, implemented by electronics. For optical communications, on-the-fly optical processing is highly desired for reduced optical-electrical-optical (OEO) conversions, so as to reduce the latency and cost. In this work, we present a proof-of-concept study of an optical FEC encoding method based on optical matrix computing by wavelength-division multiplexing (WDM) with time-wavelength interleaved manipulation. The optical FEC encoder realized by optical fiber devices features nearly equivalent net encoding gain compared with the theoretical electrical encoder. The experimental results indicate effective error correction, with 2-dB net gain in on-off keying (OOK) transmission at 20 Gb/s, supporting the realization of transmission-computing-merged systems. Meanwhile, the proposed method also supports the whole realization of FEC with both encoding and decoding.

Numerical simulation of an in-fiber broadband plasmonic polarization filter using photonic crystal fiber with dual elliptical gold layers

The demand for advanced and compact photonic filters is increasing in today's optical communication systems. This work introduces a new all-fiber broadband polarization filter using photonic crystal fiber with dual elliptical gold layers. The filtering performance is evaluated and analyzed by the finite element method. The simulation results demonstrate that the two elliptical gold layers can effectively induce a significant change in the energy of x-polarized light, leading to a great difference between the two polarized lights. By selecting reasonable structural parameters of the proposed PCF, the 1 mm-long in-fiber filter has a maximum extinction ratio of -108.90 dB, a low insertion loss of 0.64 dB around 1.31 µm and an ultra-broad bandwidth of 1020 nm, covering two common communication windows of 1.31 µm and 1.55 µm. Additionally, the filtering experimental scheme is discussed. This filter is expected to drive the advancement of optical integrated chips and all-optical communication networks.

DESIGN OF AMPLITUDE AND PHASE CONTROLLED BUTLER BEAMFORMING NETWORK FOR X/KU-BAND AIRBORNE SYNTHETIC APERTURE RADAR APPLICATIONS

Beamforming networks play an important role in today's communication systems. The Butler matrix network is one of the most useful networks used to feed array antennas and generate multi-beamforming systems. Its complexity increases with an increase in the number of input and output ports. This research work presents simulated results of an unequal amplitude 8 × 8 Butler matrix network, in which the Taylor series synthesis technique was employed to generate unequal amplitudes (-9.626, -9.125, -8.798, -8.636, -8.636, -8.798, -9.125, and -9.626 dB). The design of the Butler matrix beamforming network is based on two frequency bands, i.e., the X-band and Ku-band, with center frequencies of 9.3 and 13.265 GHz, respectively. The design mainly involves 12 hybrid couplers and eight phase shifters that can generate beams in eight different directions (-32.4°, -26.5°, -15.5°, -10.3°, 10.3°, 15.5°, 26.5°, and 32.4°). This design is based on the Taylor series expansion, which has the advantage of sidelobe level reduction of -17 dB. All of the simulations were done using advanced design system software key sight technologies. The simulations results were in line with the theoretical calculations.

Data Rakshak

Abstract: Information security is essential as data exchange moves towards an electronic system. In today's visual communication system, picture, text, and video protection are crucial. Unauthorized uses of private videos, text, and image data must be prevented. It can be difficult to find and identify unauthorized users. Several researchers have proposed several methods for protecting the transfer of texts. We created an encryption and decryption technique with security in mind. We have primarily concentrated on data security, which may be utilized by security agencies, the IT sector, SMBs, the healthcare industry, governmental organizations, the legal industry, financial and banking institutions, etc

A novel self‐timing CMOS first‐edge take‐all circuit for on‐chip communication systems

AbstractIn today's communication systems, it has become prominent for processing elements (PEs) to receive requests with simultaneous, conflicting signals, which are unpredicted and randomly triggered. In such a case, multiple overlapping signal requests can potentially compete in the same PE causing erroneous operations or a halt of the communication cycle. The authors propose a self‐timing CMOS first‐edge take‐all (FETA) circuit architecture, which examines two overlapping signals’ requests, and outputs only the leading‐edge signal while the lagging‐edge signal's request is declined. The FETA circuit functionality is considered as an essential component in First‐In‐First‐Out for metastability avoidance, which usually occurs between the write and read overlapping requests for applications related to Internet of Things, Network‐on‐Chips, and microprocessor memory management units. HSPICE simulations for a 90 nm CMOS technology are used to verify the speed up to 1 GHz. Besides, the achievable resolution is in the order of 20 ps considering process variation sensitivity based on design inheriting symmetric timing paths between the two signals. Additionally, the proposed circuit architecture adopts a self‐timing scheme obviating the overhead synchronisation circuitry, which comprises 12 D‐Type Flip‐Flops with about 300 transistors. This design is suited for HDL synthesis and FPGA application features.

Prototype fabrication of microstrip patch antenna using ceramic nanoparticles

An antenna is a passive electronic device that can both send and receive electromagnetic waves at a specific frequency range. The antennas used in today's communication systems need cutting-edge design and manufacturing techniques to provide high efficiency, great flexibility, and minimal radiation impact on the human body. Herein, we report the synthesis and subsequent characterization of Ca-doped ZnAl2O4 ceramic nanoparticles for possible microwave applications. We studied the prepared ceramic based antenna's performance in addition to material's structural properties, functional groups, surface morphology, and elemental composition. The HRTEM analysis showed spherical shape nanoparticles with a mean diameter of 16 nm and a crystallite size of 9 nm estimated by Scherrer’s formula. The prototype microstrip patch antenna using Ca-doped ZnAl2O4 demonstrated a return loss of −18.30 dB at a resonance frequency of 4.6 GHz with a bandwidth of 550 MHz.

Perkembangan Teknologi Informasi dan Komunikasi terhadap Perubahan Sistem Komunikasi Indonesia

The role of information and communication technology is no less important than human food and clothing needs. A technology is essentially created to make human life easier and more comfortable. Through communication, humans build themselves and their environment, and through communication, human civilization becomes dynamic. This research method is descriptive qualitative with purposive sampling technique in determining five informants. Data collection techniques by observation, documentation and interviews and using data analysis Miles and Huberman. The existence of technology at that time helped the government's communication process, facilitated access to information, shortened time and cut costs. The development of information and communication technology is progressing very rapidly at this time so that it triggers changes in Indonesia's communication system. In conveying information or messages to other communities in urban and rural areas, of course, it was still very limited in the past, technology with all-improvement was very difficult to obtain information or communicate. Along with developments, today's communication system changes everything to be very easy and sophisticated.Keywords: Development of Technology, Information, Communication Systems

Node Activities Learning(NAL)Approach to Build Secure and Privacy-Preserving Routing in Wireless Sensor Networks

Wireless networks are becoming the most popular in today communication systems, where users prefer to have wireless connectivity regardless of its geographic location. But the open environment of wireless communication increasing threat on the wireless networks under diverse network circumstances. The random and dynamic activity increases the vulnerability due to the complete dependency on the intermediate nodes which frequently join and leave the network. It is extremely significant to have a secure routing in such a dynamic network to preserve the data privacy. In this paper, we propose a secure and privacy routing based on Node Activities Learning (NAL) approach. This approach knows the runtime activities of the node to predict the probability of activity transformation for the intentional and unintentional activities which interrupt the data communication and affects the privacy. The mean of privacy is decided based on the node individual trust factor. It also suggests a method for the node which loses their trust due to the unintentional activities. A simulation-based evaluation study shows positive improvisation in secure routing in different malicious node environment.

A PERFORMANCE BASED COMPARATIVE ENCRYPTION AND DECRYPTION TECHNIQUE FOR IMAGE AND VIDEO FOR MOBILE COMPUTING

When data exchange advances through the electronic system, the need for information security has become a must. Protection of images and videos is important in today's visual communication system. Confidential image / video data must be shielded from unauthorized uses. Detecting and identifying unauthorized users is a challenging task. Various researchers have suggested different techniques for securing the transfer of images. In this research, the comparative study of these current technologies also addressed the types of images / videos and the different techniques of image / video processing with the steps used to process the image or video. This research classifies the two types of Encryption Algorithm, Symmetric and Encryption Algorithm, and provides a comparative analysis of its types, such as AES, MAES, RSA, DES, 3DES and BLOWFISH.

CMDNet: Learning a Probabilistic Relaxation of Discrete Variables for Soft Detection With Low Complexity

Following the great success of Machine Learning (ML), especially Deep Neural Networks (DNNs), in many research domains in 2010s, several ML-based approaches were proposed for detection in large inverse linear problems, e.g., massive MIMO systems. The main motivation behind is that the complexity of Maximum A-Posteriori (MAP) detection grows exponentially with system dimensions. Instead of using DNNs, essentially being a black-box, we take a slightly different approach and introduce a probabilistic Continuous relaxation of disCrete variables to MAP detection. Enabling close approximation and continuous optimization, we derive an iterative detection algorithm: Concrete MAP Detection (CMD). Furthermore, extending CMD by the idea of deep unfolding into CMDNet, we allow for (online) optimization of a small number of parameters to different working points while limiting complexity. In contrast to recent DNN-based approaches, we select the optimization criterion and output of CMDNet based on information theory and are thus able to learn approximate probabilities of the individual optimal detector. This is crucial for soft decoding in today's communication systems. Numerical simulation results in MIMO systems reveal CMDNet to feature a promising accuracy complexity trade-off compared to State of the Art. Notably, we demonstrate CMDNet's soft outputs to be reliable for decoders.

A Performance-Based Comparative Encryption and Decryption Technique for Image and Video for Mobile Computing

When data exchange advances through the electronic system, the need for information security has become a must. Protection of images and videos is important in today's visual communication system. Confidential image / video data must be shielded from unauthorized uses. Detecting and identifying unauthorized users is a challenging task. Various researchers have suggested different techniques for securing the transfer of images. In this research, the comparative study of these current technologies also addressed the types of images / videos and the different techniques of image / video processing with the steps used to process the image or video. This research classifies the two types of Encryption Algorithm, Symmetric and Encryption Algorithm, and provides a comparative analysis of its types, such as AES, MAES, RSA, DES, 3DES and BLOWFISH.

IQ imbalance estimation and compensation in space‐time block code multiple‐input/multiple‐output systems

AbstractDirect‐conversion radio frequency transceivers are well‐substantiated structures for today's wireless communication systems due to their ability in complexity reduction, cost, and power consumption. The unavoidable mismatch between the in‐phase (I) and quadrature‐phase (Q) branch of the analog front‐ends in the direct‐conversion transceiver leads to degrading the performance of communication systems. In this article, we address the estimation and compensation of the IQ imbalance (IQI) parameters for both the transmitter (TX) and receiver (RX) in multiple‐input/multiple‐output systems with space‐time block code (STBC) in the digital domain. This article proposes a pre‐combiner estimation and compensation of the channel and the frequency‐independent IQI scheme based on the repetitive transmission of the pilot sequence using the least square technique. It is worth noting that the proposed method can be extended to any orthogonal STBC. Moreover, the study is applied to IQI in other scenarios including only TX and only RX. Simulation results show that the proposed method achieves better performance in comparison with the existing post‐combiner technique. Furthermore, the proposed method requires lower computational complexity when the number of receive antennas is limited.

Generalized Cost-Based Job Scheduling in Very Large Heterogeneous Cluster Systems

We study job assignment in large, heterogeneous resource-sharing clusters of servers with finite buffers. This load balancing problem arises naturally in today's communication and big data systems, such as Amazon Web Services, Network Service Function Chains, and Stream Processing. Arriving jobs are dispatched to a server, following a load balancing policy that optimizes a performance criterion such as job completion time. Our contribution is a randomized Cost-Based Scheduling (CBS) policy in which the job assignment is driven by general cost functions of the server queue lengths. Beyond existing schemes, such as the Join the Shortest Queue (JSQ), the power of d or the SQ(d) and the capacity-weighted JSQ, the notion of CBS yields new application-specific policies such as hybrid locally uniform JSQ. As today's data center clusters have thousands of servers, exact analysis of CBS policies is tedious. In this article, we derive a scaling limit when the number of servers grows large, facilitating a comparison of various CBS policies with respect to their transient as well as steady state behavior. A byproduct of our derivations is the relationship between the queue filling proportions and the server buffer sizes, which cannot be obtained from infinite buffer models. Finally, we provide extensive numerical evaluations and discuss several applications including multi-stage systems.

Towards insider threats detection in smart grid communication systems

In today's communication systems, the most damaging security threats are not originating from the outsiders but from the trusted insiders - both malicious insiders and negligent insiders. Always endowed with high privileges, insiders are significantly prone to conduct acts that can cause catastrophic damages to the whole system either intentionally or unintentionally. Characterised by the full and rapid integration of information and communication technologies, smart grid - arguably the largest national critical engineering infrastructure - is suffering from a multitude of security threats initiated from both outsiders and insiders. Without security guarantee, the promising benefits of achieving an efficient, green, and reliable power grid would not be a success. In this study, the authors investigate the insider threats and summarise the existing threats detection solutions in smart grid communication systems. In addition, a novel hybrid insider threats modelling, analysis, and detection framework, which is based on stochastic Petri net and behaviour rule specifications, is proposed to contain insider threats in smart grid communication systems.

Performance Analysis of Wireless Local Area Network Using Router Tenda N-300

Today's wireless communication system is a trend for the information society. This is inseparable from communication needs with high mobility and low costs. One of them is the Wireless Local Area network with the IEEE 802.11 standard. Wireless LAN is a communication technology that uses radio wave transmission media by utilizing free space as a transmission line. The transmitted signal is strongly influenced by distance, frequency, transmitter power, receiver sensitivity, and antenna gain. A loss occurs in the process of transmitting data from the sender to the recipien. In order to no loss that occurs, it requires a good performance, and a wide coverage area. The purpose of this study is to analyze the QoS data, calculate the coverage area, receiver power, and compare the results of theoretical calculations with the measurement results. The analysis results show the average throughput for each data rate of 6 Mbps, 15 Mbps and 35 Mbps at 383.8 kbps, 328.2 kbps and 329.8 kbps. The average delay is 5.28 ms, 4.81 ms and 4.66 ms. The average packet loss is 2.83% ms, 2.66% ms and 2.16% ms. The average jitter is 0.036 ms, 0.032 ms and 0.014 ms.

The Transimpedance Amplifier [A Circuit for All Seasons

Many of today's communication systems incorporate a transimpedance amplifier (TIA). Although the TIA concept is as old as feedback amplifiers [1], it was in the late 1960s and early 1970s that TIAs found widespread usage in optical coupling and optical communication receivers. In a patent filed in 1967, Miller proposes the circuit shown in Figure 1 [2], which consists of two TIAs for converting a photodiode's current to a differential output voltage. Additionally, these amplifiers have become popular in radio-frequency (RF) receivers in the past 10 years [3]. This article deals with TIA design for optical and RF applications.

A Network Delay Factor Model Based on the Hidden Markov Model and Latent Dirichlet Allocation

Network systems are widely used in today's digital communication systems and applications. Network delay is a very important factor affecting the efficiency and reliability of the system, and researchers often use a model to predict and understand the causes and patterns of delay. For our model, we propose beginning with the Hidden Markov Model (HMM) of the transmission network, which is used to analyze the network's operational situation and to predict the approximate state of the system into the future using the HMM prediction algorithm. Then, employing Latent Dirichlet Allocation (LDA), we put forward the Delay Factor Model (DFM) value for the delay. In the DFM, we need to map the delay's interval to an integer, designated as DII (Delay Interval Integer), and the factors returned define the hidden states of the HMM. From the view of the DFM, DII is generated from a factor and the previous DII randomly. We use the Gibbs Sampling approach to obtain an estimation of the DFM's parameters. By defining the HMM and DFM, we can forecast future delay with high accuracy, and the result can be shown to follow the peaks and troughs of the real operation of the network system's delay patterns.

True random bit generators based on current time series of contact glow discharge electrolysis

Random bit generators (RBGs) in today's digital information and communication systems employ a high rate physical entropy sources such as electronic, photonic, or thermal time series signals. However, the proper functioning of such physical systems is bound by specific constrains that make them in some cases weak and susceptible to external attacks. In this study, we show that the electrical current time series of contact glow discharge electrolysis, which is a dc voltage-powered micro-plasma in liquids, can be used for generating random bit sequences in a wide range of high dc voltages. The current signal is quantized into a binary stream by first using a simple moving average function which makes the distribution centered around zero, and then applying logical operations which enables the binarized data to pass all tests in industry-standard randomness test suite by the National Institute of Standard Technology. Furthermore, the robustness of this RBG against power supply attacks has been examined and verified.

Decreasing Size, Increasing Battery Life: A Wide-Band, Low-Noise Amplifier for 5G Multistandard Broadband Communications

With the introduct ion of cloudbased services, online social networks, and multimedia streaming over the past decade or so, the demand for high-bandwidth mobile communications has increased rapidly. At the same time, consumers expect long battery life for their handheld devices. Fifth-generation (5G) wireless broadband will provide bandwidth of multiple gigabits per second, requiring wider bands at higher frequency ranges than today's communication systems use.

MIMO-OFDM Energy Efficient Cognitive System with Intelligent Anti-jam Capability

Today's wireless communication systems are highly susceptible to malicious jamming attacks and interference signals. These attacks are sent via communication link at the same frequency as the inten...