The proliferation of ubiquitous computing applications created a multi-dimensional optimization problem that includes several conflicting variables such as spectral efficiency, complexity, power consumption, delay, and error probability. To relax the problem and provide efficient solutions, it was necessary to augment the currently overutilized radio spectrum with new frequency bands such as the optical spectrum, which can be used to off-load some of the traffic of certain applications. Therefore, this paper presents an efficient system design that uses amplitude-coherent (AC) detection to reduce OWC system’s complexity, improve its reliability and spectral efficiency. More specifically, we use amplitude shift keying with orthogonal frequency division multiplexing (OFDM) at the transmitter, and AC detection at the receiver. The complexity reduction is achieved by using a low complexity detector, channel estimator, and peak-to-average power ratio (PAPR) reduction scheme. The spectral efficiency is achieved by using real data symbols with discrete cosine transform (DCT), which requires a subcarrier spacing that is 50% of the discrete Fourier transform (DFT), and does not require Hermitian symmetry to generate real-valued OFDM signals. Moreover, the derived channel estimator is blind, and the PAPR reduction scheme does not require a feedback overhead between the transmitter and receiver.

We demonstrate photonic RF phase encoding based on an integrated micro-comb source. By assembling single-cycle Gaussian pulse replicas using a transversal filtering structure, phase encoded waveforms can be generated by programming the weights of the wavelength channels. This approach eliminates the need for RF signal generators for RF carrier generation or arbitrary waveform generators for phase encoded signal generation. A large number of wavelengths—up to 60—were provided by the microcomb source, yielding a high pulse compression ratio of 30. Reconfigurable phase encoding rates ranging from 2 to 6 Gb/s were achieved by adjusting the length of each phase code. This work demonstrates the significant potentials of this microcomb-based approach to achieve high-speed RF photonic phase encoding with low cost and footprint.

In this correspondence, we correct the ergodic capacity versus SNR curves of the coherent multiple-input multiple-output (MIMO) channel in independent and identically distributed (IID) Rayleigh fading in the correspondence cited in the title. More importantly, the corrected capacity results present an interesting and compelling contrast between performances of the coherent MIMO systems with and without channel state information at the transmitter; whereas this view is somewhat limited in in the correspondence cited in the title because of flaws in the capacity curves.

In this paper, a satellite-aerial integrated computing (SAIC) architecture in disasters is proposed, where the computation tasks from two-tier users, i.e., ground/aerial user equipments, are either locally executed at the high-altitude platforms (HAPs), or offloaded to and computed by the Low Earth Orbit (LEO) satellite. With the SAIC architecture, we study the problem of joint two-tier user association and offloading decision aiming at the maximization of the sum rate. The problem is formulated as a 0-1 integer linear programming problem which is NP-complete. A weighted 3-uniform hypergraph model is obtained to solve this problem by capturing the 3D mapping relation for two-tier users, HAPs, and the LEO satellite. Then, a 3D hypergraph matching algorithm using the local search is developed to find a maximum-weight subset of vertex-disjoint hyperedges. Simulation results show that the proposed algorithm has improved the sum rate when compared with the conventional greedy algorithm.

The use of large-scale antenna arrays grants considerable benefits in energy and spectral efficiency to wireless systems due to spatial resolution and array gain techniques. By assuming a dominant line-of-sight environment in a massive MIMO scenario, we derive analytical expressions for the sum-capacity. % Then, we show that convenient simplifications on the sum-capacity expressions are possible when working at low and high SNR regimes. % Furthermore, in the case of a high SNR regime, it is demonstrated that the Gamma PDF can approximate the PDF of the instantaneous channel sum-capacity as the number of BS antennas grows. A second important demonstration presented in this work is that a Gamma PDF can also be used to approximate the PDF of the summation of the channel’s singular values as the number of devices increases. Finally, it is important to highlight that the presented framework is useful for a massive number of Internet of Things devices as we show that the transmit power of each device can be made inversely proportional to the number of BS antennas.

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px ‘Times New Roman’; min-height: 15.0px} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px ‘Times New Roman’} span.s1 {font: 12.0px ‘Times New Roman’} Mobility is a key aspect in current cellular networks, allowing users to access the provided services almost anywhere. When a user transitions from a base station’s coverage area to another cell being serviced by another station, a handoff process takes place, where resources are released in the first base station, and allocated in the second for the purpose of servicing the user. Predicting the future location of a cell phone user allows the handoff process to be optimized. This optimization allows for a better utilization of the available resources, regarding bot the transmitted power and the frequency allocation, resulting in less amount of wasted power in unwanted directions and the possibility of reusing frequencies in a single base station. To achieve this goal, Deep Learning techniques are proposed, which have proven to be efficient tools for predicting and detecting patterns. The purpose of this paper is to give an overview of the state of the art in Deep Learning techniques for making spatio-temporal predictions, which could be used to optimize the handoff process in cellular systems.

Entering the 5G/6G era, the core concept of human-centric communications has intensified the search effort into analytical frameworks for integrating technological and non-technological domains. Among non-technological domains, human behavioral, psychological, and socio-economic contexts are widely considered as indispensable elements for characterizing user experience (UE). In this study, we introduce the prospect theory as a promising methodology for modeling UE and perceptual measurements for human-centric communications. As the founding pillar of behavioral economics, the prospect theory proposes the non-linear quantity and probability perception of human psychology, which extends to five fundamental behavioral attributes that have profound implications for diverse disciplines. By expatiating on the prospect theoretic framework, we aim to provide a guideline for developing human-centric communications and articulate a novel interdisciplinary research area for further investigation.

We consider power efficient scheduling and precoding solutions for multiantenna hybrid digital-analog transmission systems that use Time-Modulated Arrays (TMAs) in the analog domain. TMAs perform beamforming with switches instead of conventional Phase Shifters (PSs). The extremely low insertion losses of switches, together with their reduced power consumption and cost make TMAs attractive in emerging technologies like massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) systems. We propose a novel analog processing network based on TMAs and provide an angular scheduling algorithm that overcomes the limitations of conventional approaches. Next, we pose a convex optimization problem to determine the analog precoder. This formulation allows us to account for the Sideband Radiation (SR) effect inherent to TMAs, and achieve remarkable power efficiencies with a very low impact on performance. Computer experiments results show that the proposed design, while presenting a significantly better power efficiency, achieves a throughput similar to that obtained with other strategies based on angular selection for conventional architectures.

We have thoroughly studied the paper of Perazzo et al., which presents a routing attack named DIO suppression attack with its impact analysis. However, the considered simulation grid of size 20mx20m does not correspond to the results presented in their paper. We believe that the incorrect simulation detail needs to be rectified further for the scientific correctness of the results. In this comment, it is shown that the suppression attack on such small sized network topology does not have any major impact on routing performance, and specific reason is discussed for such behavior.

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Helvetica} span.s1 {font: 7.5px Helvetica} xAbstract—In this paper, the physical layer security of a dualhop underlay uplink cognitive radio network is investigated over Nakagami-m fading channels. Specifically, multiple secondary sources are taking turns in accessing the licensed spectrum of the primary users and communicating with a multiantenna secondary base station (D) through the aid of a multiantenna relay R in the presence of M eavesdroppers that are also equipped with multiple antennas. Among the remaining nodes, one jammer is randomly selected to transmit an artificial noise to disrupt all the eavesdroppers that are attempting to intercept the communication of the legitimate links i.e., Si -R and R-D. The received signals at each node are combined using maximum-ratio combining. Secrecy analysis is provided by deriving closed-form and asymptotic expressions for the secrecy outage probability. The impact of several key parameters on the system’s secrecy e.g., transmit power of the sources, number of eavesdroppers, maximum tolerated interference power, and the number of diversity branches is investigated. Importantly, by considering two scenarios, namely (i) absence and (ii) presence of a friendly jammer, new insights are obtained for the considered communication system. Especially, we tend to answer to the following question: Can better secrecy be achieved without jamming by considering a single antenna at eavesdroppers and multiple-ones at the legitimate users (i.e., relay and enduser) rather than sending permanently an artificial noise and considering that both the relay and the destination are equipped with a single antenna, while multiple antennas are used by the eavesdroppers? The obtained results are corroborated through Monte Carlo simulation and show that the system’s security can be enhanced by adjusting the aforementioned parameters.

Abstarct: In the RPL routing protocol, DODAG Information Solicitation (DIS) control messages are sent by nodes to join the network. In turn, the receiver node replies with DODAG Information Object (DIO) control message after resetting its trickle timer. A malicious node can utilize this RPL protocol behavior to perform the DIS flooding attack by sending illegitimate DIS frequently which forces normal nodes to reset their trickle timers and flood the network with DIO messages. In this study, we show that such attacks can severely degrade the performance of Low Power and Lossy Networks (LLNs) because of the increase in control packet overhead and power consumption. To address DIS flooding attacks, we propose a lightweight mitigation scheme that detects and mitigate such attacks in order to improve LLNs performance. Note:To be published in proceedings of 2019 IEEE Region 10 Conference (TENCON 2019)

Next generation wireless networks are expected to provide much higher data throughput and reliable connections for a far larger number of wireless service subscribers and machine-type nodes, which result in increasingly stringent requirements of spectral efficiency (SE) and energy efficiency (EE). Orthogonal frequency-division multiplexing with index modulation (OFDM-IM) stands out as a promising solution to satisfy the SE requirement with a reasonable increase in system complexity. However, the EE of OFDM-IM is still required to be enhanced. Moreover, diversity gain is hardly harvested in OFDM-IM systems, which hinders further reliability enhancement. In this regard, relay assisted OFDM-IM, as a promising joint paradigm to achieve both high SE and EE, was proposed and has been studied since last year. The objectives of this article are to summarize the recent achievements of this joint paradigm, articulate its pros and cons, and reveal the corresponding challenges and future work.

Vehicle-to-Everything (V2X) using Visible Light Communication (VLC) channels can be seen as an economically viable option to replace the existing modes of vehicular communications in the near future. In this paper, we have analyzed the performance of VLC based V2X communication under various environmental deterrents viz. Light Fog, Dense Fog, Light Smoke and Dense Smoke using a proof-of-concept testbed. A series of experiments were conducted to investigate the effects of environmental deterrents over VLC based Line-of-Sight as well as non-Line of Sight V2X transmission with respect to distance and angular variations. On-Off-keying (OOK) modulation has been selected as the modulation scheme, as defined in VLC standard (IEEE 802.15.7) for the transmission of information bits between a transmitter LED and a photo-diode receiver. The experimental results show the feasibility of VLC-based V2X systems with reliable data transmission under different environmental deterrents with a fairly good signal-to-noise ratio (SNR), even under dense-fog and smoke conditions where the attenuation in average optical power at the receiver, is quite high.

Study of downlink secrecy rate in Massive MIMO employing 1-bit ADCs/DACs in the presence of pilot attack

Communication breakdowns during natural disasters can significantly restrict disaster management operations. Furthermore, cellular networks may also be unreliable in such scenarios. Hence, establishing communication using alternative means is of importance in these scenarios. In this paper, we propose a prototype system to establish communication using wireless mesh network, through the use of stationary and mobile ground nodes, and aerial nodes using unmanned aerial vehicles (UAVs). This network is ad hoc and establishes connectivity without the usage of a cellular network or internet. Our system provides a complete end to end architecture, where we deploy an android application on smartphones at the user-end, the ad hoc network comprising of stationary and mobile nodes, and a graphical user interface (GUI) at the base station that facilitates situational awareness. We use the Robot Operating System (ROS) as the middleware for message synchronization between the nodes as well for UAV control. We evaluate the system for different system configurations by using UAVs and a semi-autonomous car. Our experimental results show that the system could be indispensable in providing large scale connectivity.

JPL’s own data correlate to 1% NEAR and Rosetta trajectory discrepancies to an unexpected doubling of path times in phase locked tracking. NEAR’s radar residuals illustrate the doubling to 5σ. Analysis of these and other NASA-tracked flybys shows that a distance sensitive anomalous signal generally exists. (Presented at IEEE NAECON 2019)

In this paper, internet of things (IoT) connectivity in rural areas is investigated. Both fronthaul and backhaul considerations are studied. First, intelligent radio resource management (RRM) and network planning techniques are discussed for IoT access/fronthaul networks. The proposed RRM scheduling approach was shown to lead to good performance in scheduling IoT devices. Then, several backhauling techniques for providing connectivity to rural areas are investigated and their cost efficiency is analyzed. Techniques based on free space optics with solar powered devices are found to be a suitable backhaul solution.

Smart building (SB), a promising solution to fast-paced and continuous urbanization around the world, includes the integration of a wide range of systems and services and involves the construction of multiple layers. SB is capable of sensing, acquiring, and processing a very large amount of data as well as performing appropriate actions and adaptation. Rapid increases in the number of connected nodes and thereby the data transmission demand of SB have led to conventional transmission and processing techniques becoming insufficient to provide satisfactory services. In order to enhance the intelligence of SBs and achieve efficient monitoring and control, sixth generation (6G) communication technologies, particularly indoor visible light communications (VLC) and machine learning (ML), are required to be incorporated in SBs. Herein, we envision a novel SB framework featuring a reliable data transmission network, powerful data processing, and reasoning abilities, all of which are enabled by 6G communications. Primary simulation results support the promising visions of the proposed SB framework.

The controversy and argument on the usefulness of the physical layer (PHY) academic research for wireless communications are long-standing since the cellular communication paradigm gets to its maturity. In particular, researchers suspect that the performance improvement in cellular communications is primarily attributable to the increases in telecommunication infrastructure and radio spectrum instead of the PHY academic research, whereas concrete evidence is lacking. To respond to this controversy from an objective perspective, we employ econometric approaches to quantify the contributions of the PHY academic research and other performance determinants. Through empirical analysis and the quantitative evidence obtained, albeit preliminary, we shed light on the following issues: 1) what determines the cross-national differences in cellular network performance; 2) to what extent the PHY academic research and other factors affect cellular network performance; 3) what suggestions we can obtain from the data analysis for the stakeholders of the PHY research. To the best of our knowledge, this article is the first `empirical telecommunication research,' and the first effort to involve econometric methodologies to evaluate the usefulness of the PHY academic research.

The standardization of fifth generation (5G) communications has been completed, and the 5G network should be commercially launched in 2020. As a result, the visioning and planning of sixth generation (6G) communications has begun, with an aim to provide communication services for the future demands of the 2030s. Here we provide a vision for 6G that could serve a research guide in the post-5G era. We suggest that human-centric mobile communications will still be the most important application of 6G and the 6G network should be human centric. Thus, high security, secrecy, and privacy should be key features of 6G and should be given particular attention by the wireless research community. To support this vision, we provide a systematic framework in which potential application scenarios of 6G are anticipated and subdivided. We subsequently define key potential features of 6G and discuss the required communication technologies. We also explore the issues beyond communication technologies that could hamper research and deployment of 6G.

To meet the increasing demands for passenger data rates, modern railway communication networks face significant challenges. The advent of 5G communications after the long-term evolution (LTE) and LTE-Advanced (LTE-A) systems provides several technological advances to address these challenges. In this paper, after reviewing the main 5G communication aspects for modern railways, we present methods to ensure connectivity and energy efficiency for the passengers’ user equipment (UE) through the use of mobile relays (MRs) on top of the train wagons in conjunction with intelligent resource allocation. Relevant challenges to train connectivity are also presented, and suitable solutions are outlined.

Providing connectivity to around half of the World population living in rural or underprivileged areas is a tremendous challenge, but also a unique opportunity. In this paper, a survey of technologies for providing connectivity to rural areas, and that can help address this challenge, is provided. Fronthaul and backhaul techniques are discussed. In addition, energy and cost efficiency of the studied technologies are analyzed. Typical application scenarios in rural areas are discussed, and several country-specific use cases are surveyed. Directions for future evolution of rural connectivity are outlined.

Great people like Stephen Hawking and Max Brito have been suffering from this crippling phenomenon. Our project is an attempt to make lives of the physically challenged people by our extravagant project. We mean self-reliant, which will thereby reinstate their confidence and their happiness. The idea is to create an Eye Monitored System which allows movement of the patient‟s wheelchair depending on the eye movements. We know that a person suffering from quadriplegia can partially move his eyes and tilt his head, thus presenting an opportunity for detecting those movements. We have created a device where a patient sitting on the Wheel Chair assembly looking directly at the camera, is able to move in a direction just by looking in that direction. The camera signals are monitored by a MATLAB script, which will then guide the motors wired to the AtMega1284P Microcontroller over the Serial Interface to move in a particular direction. The system is cost effective and thus can be used by patients spread over a large economy range. We have implement a Smart mobile application to paramount our project and thereby we justify our project name “The Smart Mobility For Physically Challenged”

In this paper, the concept and recent development of exploiting frequency diverse array (FDA) and its variants for the physical-layer wireless security have been revisited and carefully examined. Following rigorous analytical derivation and illustrative simulations, the authors argue that the investigations performed in some recent works did not reveal one critical issue facing the real-world applications, and system models established and used before were based on an unrealistic assumption, i.e. that the legitimate and eavesdropping users at different ranges sample the signal waveforms at the same time instant. This misunderstanding results in conclusions that are misleading. The authors aim to take the first step to divert research efforts and rectify the previous problematic analyses. The authors prove that the FDA cannot secure a free-space wireless transmission in range domain, because the previously claimed ‘secure reception region’ propagates in range domain as time elapses.