Internet of Things (IoT): Opportunities, issues and challenges towards a smart and sustainable future

There has been a tremendous growth in the number of smart devices and their applications (e.g., smart sensors, wearable devices, smart phones, smart cars, etc.) in use in our everyday lives. This is accompanied by a new form of interconnection between the physical and digital worlds, commonly known as the Internet of Things (IoT). This is a paradigm shift, where anything and everything can be interconnected via a communication medium. In such systems, security is a prime concern and protecting the resources (e.g., applications and services) from unauthorized access needs appropriately designed security and privacy solutions. Building secure systems for the IoT can only be achieved through a thorough understanding of the particular needs of such systems. The state of the art is lacking a systematic analysis of the security requirements for the IoT. Motivated by this, in this paper, we present a systematic approach to understand the security requirements for the IoT, which will help designing secure IoT systems for the future. In developing these requirements, we provide different scenarios and outline potential threats and attacks within the IoT. Based on the characteristics of the IoT, we group the possible threats and attacks into five areas, namely communications, device/services, users, mobility and integration of resources. We then examine the existing security requirements for IoT presented in the literature and detail our approach for security requirements for the IoT. We argue that by adhering to the proposed requirements, an IoT system can be designed securely by achieving much of the promised benefits of scalability, usability, connectivity, and flexibility in a practical and comprehensive manner.

Security Requirements for the Internet of Things: A Systematic Approach.

3D Printing of Flexible Strain Sensor Array Based on UV-Curable Multiwalled Carbon Nanotube/Elastomer Composite

This paper presents an implementation of a novel capacitance level sensor. The objective of the proposed work is to design a capacitive level sensor (CLS) which will have improved sensitivity and reduced sensor delay as compared to existing design. Performance analysis of the exiting parallel rod and cylindrical type sensors is carried to understand the characteristics in terms of sensitivity and sensor delay. A novel design with variations in electrodes structure from conventional design to helical structure is proposed in this work. Theoretical computation and practical validation of the designed CLS shows better performance in comparison to existing sensors. Improvement in sensitivity is found to be more than 99.99% in comparison to cylindrical and parallel rods. Helical type sensor response time is quicker by 27.73 s in comparison to cylindrical and by 6.46 s in comparison to parallel rod CLS. Also the effect of change in liquid type and liquid temperature on sensor output is analysed and results showed increased sensor output for higher permittivity and temperature of liquid.

A novel helical electrode type capacitance level sensor for liquid level measurement

Directional modulation (DM) as a physical layer security technique has been studied from many different aspects recently. Normally all existing designs based on antenna arrays lead to varying weight coefficients for different antennas and for different signal symbols, which poses a particular challenge for feed circuits design in analogue implementation. In this paper, to reduce the implementation complexity, a constant magnitude constraint is proposed for the first time, and the resultant non-convex constraint can be modified to a convex form so that the problem can be solved conveniently by existing convex optimisation toolboxes. Design examples are provided to show the effectiveness of the proposed design.

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Directional Modulation Design Under a Constant Magnitude Constraint for Weight Coefficients

As a key technology of the 5G communication system, device-to-device (D2D) communications have drawn significant research interests. However, the advantage of D2D communications may be limited when D2D users are far away from each other or the communication environments are harsh. In order to extend the range of D2D communications, a promising way is to use relaying technique to assist the communications. In this paper, we use a two-way amplify-and-forward (AF) relay to assist the underlay D2D communications and investigate the power control problem. Specifically, we formulate the power control problem as the optimization of the performance of the D2D link while fulfilling the quality-of-service (QoS) requirement of the cellular link. Two optimization objectives are considered for the D2D link, i.e., maximization of the minimum SINR at D2D users and maximization of the sum-rate of D2D users. For the first optimization objective, we can compare the possible optimal solutions for the three boundary conditions and obtain the optimal solutions. For the second optimization objective, we can convert the objective function into a concave function based on difference of convex (D. C.) structure, and use an iterative algorithm to solve the optimization problem. The simulation results show that the proposed power control scheme can improve the performance of the D2D link.

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Power Control for Two-Way AF Relay Assisted D2D Communications Underlaying Cellular Networks

Traditional directional modulation designs are normally based on a single phased array, with the assumption that eavesdroppers and desired users are in different directions. However, it is not always the case, as it is possible that they are in the same direction. As a result, signals received by eavesdroppers will be approximately the same as desired users. To solve the problem, a multiple antenna array model is introduced, and the principle of the design is that the eavesdropper located in the same direction as the desired user for one antenna array may not be in the same direction for another antenna array. Based on such a model, in this paper, a power minimization constraint for the design is proposed, and an artificial noise component is included, resulting in a scrambled phase response for eavesdroppers. Beam pattern, phase pattern, and bit error rate are used as metrics to show the effectiveness of the designs based on multiple fixed antenna arrays and location optimized antenna arrays, respectively.

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Positional Modulation Design Based on Multiple Phased Antenna Arrays

Directional modulation (DM) as a physical layer security technique has been studied based on the traditional antenna arrays; however, in most of the designs, only one signal is transmitted at one carrier frequency. In this paper, signal polarization information is exploited, and a new DM scheme is designed, which can transmit a pair of orthogonally polarized signals to the same direction at the same frequency simultaneously, resulting in doubled channel capacity. These two signals can also be considered as one composite signal using a four-dimensional (4-D) modulation scheme across the two polarization diversity channels. Moreover, compressive sensing (CS)-based formulations for designing sparse crossed-dipole arrays in this context are proposed to exploit the degrees of freedom in the spatial domain for further improved performance, as demonstrated by various design examples.

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Orthogonally Polarized Dual-Channel Directional Modulation Based on Crossed-Dipole Arrays

Multi-carrier-based waveform design for directional modulation (DM) is studied, where simultaneous data transmission over multiple frequencies can be achieved, with given phase distribution at the main lobe and as random as possible over sidelobe regions for each frequency. The design can be implemented efficiently by the inverse discrete Fourier transform (IDFT) structure. However, the problem of multi-carrier design is the high peak-to-average-power ratio (PAPR) of the resultant signals, leading to non-linear distortion when signal peaks pass through saturation regions of a power amplifier. To solve the problem, the $\text {PAPR}\leq \rho ~(\rho \geq 1)$ constraint is considered in the design, and a solution called wideband beam and phase pattern formation by Newton's method (WBPFN) is proposed. The resultant beam patterns, phase patterns, and complementary cumulative distribution function (CCDF) of PAPR are presented to demonstrate the effectiveness of the proposed design.

/pdf/multi-carrier-waveform-design-for-directional-modulation-3ga61baizc.pdf

Bo Zhang

Papers

Power Control for Two-Way AF Relay Assisted D2D Communications Underlaying Cellular Networks

Positional Modulation Design Based on Multiple Phased Antenna Arrays

Orthogonally Polarized Dual-Channel Directional Modulation Based on Crossed-Dipole Arrays

Directional Modulation Design Under a Constant Magnitude Constraint for Weight Coefficients

Multi-Carrier Waveform Design for Directional Modulation Under Peak to Average Power Ratio Constraint