Iet Communications 

About: Iet Communications is an academic journal published by Institution of Engineering and Technology. The journal publishes majorly in the area(s): Communication channel & Fading. It has an ISSN identifier of 1751-8628. It is also open access. Over the lifetime, 4747 publications have been published receiving 47618 citations. The journal is also known as: Institution of Engineering and Technology communications.

Survey of automatic modulation classification techniques: classical approaches and new trends

Abstract: The automatic recognition of the modulation format of a detected signal, the intermediate step between signal detection and demodulation, is a major task of an intelligent receiver, with various civilian and military applications. Obviously, with no knowledge of the transmitted data and many unknown parameters at the receiver, such as the signal power, carrier frequency and phase offsets, timing information and so on, blind identification of the modulation is a difficult task. This becomes even more challenging in real-world scenarios with multipath fading, frequency-selective and time-varying channels. With this in mind, the authors provide a comprehensive survey of different modulation recognition techniques in a systematic way. A unified notation is used to bring in together, under the same umbrella, the vast amount of results and classifiers, developed for different modulations. The two general classes of automatic modulation identification algorithms are discussed in detail, which rely on the likelihood function and features of the received signal, respectively. The contributions of numerous articles are summarised in compact forms. This helps the reader to see the main characteristics of each technique. However, in many cases, the results reported in the literature have been obtained under different conditions. So, we have also simulated some major techniques under the same conditions, which allows a fair comparison among different methodologies. Furthermore, new problems that have appeared as a result of emerging wireless technologies are outlined. Finally, open problems and possible directions for future research are briefly discussed.

Improved energy detection spectrum sensing for cognitive radio

Abstract: Energy detection constitutes a preferred approach for spectrum sensing in cognitive radio owing to its simplicity and applicability (it works irrespective of the signal format to be detected) as well as its low computational and implementation costs. The main drawback, however, is its well-known detection performance limitations. Various alternative detection methods have been shown to outperform energy detection, but at the expense of increased complexity and confined field of applicability. In this context, this work proposes and evaluates an improved version of the energy detection algorithm that is able to outperform the classical energy detection scheme while preserving a similar level of algorithm complexity as well as its general applicability regardless of the particular signal format or structure to be detected. The performance improvement is evaluated analytically and corroborated with the experimental results.

Performance analysis of free-space optical communication systems over atmospheric turbulence channels

Abstract: Turbulence fading is one of the main impairments affecting the operation of free-space optical (FSO) communication systems. The authors study the performance of FSO communication systems, also known as wireless optical communication systems, over log-normal and gamma-gamma atmospheric turbulence-induced fading channels. These fading models describe the atmospheric turbulence because of its very good agreement with experimental measurement data. Closed-form expressions for the average (ergodic) capacity and the outage probability are derived for both statistical models. Another contribution of this work is a study of how the performance metrics are affected by the atmospheric conditions and other parameters such as the length of the link and the receiver's aperture diameter. The derived analytical expressions are verified by various numerical examples and can be used as an alternative to time-consuming Monte-Carlo simulations.

Security attacks and solutions for vehicular ad hoc networks

Abstract: Vehicular ad hoc networks (VANETs) have attracted a lot of attention over the last few years They have become a fundamental component of many intelligent transportation systems and VANETs are being used to improve road safety and enable a wide variety of value-added services Many forms of attacks against VANETs have emerged recently that attempt to compromise the security of such networks Such security attacks on VANETs may lead to catastrophic results such as the loss of lives or loss of revenue for those value-added services Therefore making VANETs secure has become a key objective for VANET designers To develop and deploy secure VANET infrastructures remains a significant challenge The authors discuss some of the main security threats and attacks that can be exploited in VANETs and present the corresponding security solutions that can be implemented to thwart those attacks

Intelligent walls as autonomous parts of smart indoor environments

Abstract: This study introduces the concept of an intelligent wall as an autonomous part of a smart indoor environment for cognitive wireless networks. Here, an intelligent wall is a wall inside a building equipped with an active frequency-selective surface, simple low-cost sensors and a cognitive engine with machine-learning ability. Using simulations, it has been shown that the smart environment based on intelligent walls can react to the immediate demands of an indoor wireless system, control radio coverage and, consequently, influence the overall system performance. The concept of the intelligent walls is described and evaluated based on a simple implementation of an arrangement of two intelligent walls in a conference centre scenario. Artificial neural networks were employed in the cognitive engine. Elementary orthogonal frequency division multiple access static system simulations are used to analyse the influence of the smart environment on the system performance. Results are discussed in detail and typical characteristics of the aforementioned system are derived and summarised.