In this work, we present a unified framework for the performance analysis of dual-hop underwater wireless optical communication (UWOC) systems with amplify-and-forward fixed gain relays in the presence of air bubbles and temperature gradients. Operating under either heterodyne detection or intensity modulation with direct detection, the UWOC is modeled by the unified mixture Exponential-Generalized Gamma distribution that we have proposed based on an experiment conducted in an indoor laboratory setup and has been shown to provide an excellent fit with the measured data under the considered lab channel scenarios. More specifically, we derive the cumulative distribution function (CDF) and the probability density function of the end-to-end signal-to-noise ratio (SNR) in exact closed-form in terms of the bivariate Fox's H function. Based on this CDF expression, we present novel results for the fundamental performance metrics such as the outage probability, the average bit-error rate (BER) for various modulation schemes, and the ergodic capacity. Additionally, very tight asymptotic results for the outage probability and the average BER at high SNR are obtained in terms of simple functions. Furthermore, we demonstrate that the dual-hop UWOC system can effectively mitigate the short range and both temperature gradients and air bubbles induced turbulences, as compared to the single UWOC link. All the results are verified via computer-based Monte-Carlo simulations.

In this paper, we focuse on mitigating the damage due to a seismic event in a mid-size building using wireless structure control (WSC). We consider the nature of wireless communication channels and integrates it into a structural control system that minimizes the building response to external excitation - earthquake events. The control and communication constraints in terms of delay and channel reliability are analyzed and incorporated into the regulator model, which incorporates both estimator and feedback command. The short packet formulation provides the ability to link latency and channel reliability, i.e. error rates. This error-delay coupling allows us to analyze the performance of the control system for several scenarios and channel variation models. The simulations show that measurement error harmfully impacts the system performances more than delayed measurements. On the other hand, it is demonstrated that delayed control commands have more impact on the structural response than lost command packets.

Backscatter modulation (BM), usually used for radio frequency identifications, has the potential to be exploited in a wider range of applications such as the Internet of Things and wireless sensor networks. In this paper, we leverage the BM by increasing its down-link (from reader to tag) and up-link (from tag to reader) ranges. We propose two active two-way BM tag configurations, named parallel and series. For both configurations, we use active loads in the tag modulators to maximize the BM range and implement the desired backscattered constellation, subject to no data loss in the down-link path. Contrary to most existing BM studies, we use Thevenin/Norton equivalent circuit, only to calculate the received power at tag, while we derive the tag backscattered power using the antenna scatterer theorem. Moreover, we obtain a closed-form expression of the average bit error probability (BEP) at the reader in Rician fading channel environment for both tag configurations. We compare the proposed active BM tags with the conventional passive BM tags. The simulation results prove that for an average BEP equal to 10-4, an SNR improvement of up to 19 and 24 dB can be achieved for parallel and series configurations, respectively.

This paper develops a mathematical paradigm to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). Particularly, we study the dominant intra-cell interferer problem that appears between HD users scheduled on the same FD-channel. The distribution of the dominant interference is first characterized via its distribution function, which is derived in closed-form. Assuming Nakagami-m fading, the probability of error for different modulation schemes is studied and a unified closed-form expression for the average symbol error rate is derived. To this end, we show the effective downlink throughput gain, harvested by employing FD communication at a BS that serves HD users, as a function of the signal-to-interference-ratio when compared to an idealized HD interference and noise free BS operation.

In a wireless structural control system, a linear quadratic Gaussian regulator, under measurements loss, is used to limit the RMS structural response to natural hazards. The analysis shows the dependence of the state estimation error, and corresponding control performance, to the packet error probability and transmission delay. These metrics are studied for two communication access techniques: code-division multiple-access (CDMA) and time-division multiple-access (TDMA). By simulating a 9-story benchmark building with real earthquake inputs, it is shown that CDMA scheme performs better with few sensors scenario due to the low latency, however, more sensors may decrease the closed-loop performance due to high delay (TDMA) or high lost rate (CDMA).

This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station. The developed model is used to motivate long term pairing for users that have a non-line of sight (NLOS) interfering link. Consequently, we study the interferer limited problem that appears between NLOS HD users-pair that are scheduled on the same FD-channel. The distribution of the interference is first characterized via its distribution function, which is derived in closed form. Then, a comprehensive performance assessment for the proposed pairing scheme is provided by assuming Extended Generalized-$\mathcal {K}$ fading for the downlink and studying different modulation schemes. To this end, a unified closed-form expression for the average symbol error rate is derived. Furthermore, we show the effective downlink throughput gain harvested by the pairing NLOS users as a function of the average signal-to-interference-ratio when compared with an idealized HD scenario with neither interference nor noise. Finally, we show the minimum required channel gain pairing threshold to harvest downlink throughput via the FD operation when compared with the HD case for each modulation scheme.

In this paper, we analyze the end-to-end performance of dual-hop free-space optical (FSO) fixed gain relaying systems under heterodyne detection and intensity modulation with direct detection techniques in the presence of atmospheric turbulence as well as pointing errors. In particular, we derive the cumulative distribution function (cdf) of the end-to-end signal-to-noise ratio (SNR) in exact closed form in terms of the bivariate Fox's H function. Capitalizing on this cdf expression, novel closed-form expressions for the outage probability, the average bit-error rate (BER) for different modulation schemes, and the ergodic capacity of dual-hop FSO transmission systems are presented. Moreover, we present very tight asymptotic results for the outage probability and the average BER at high SNR regime in terms of simple elementary functions, and we derive the diversity order of the considered system. By using dual-hop FSO relaying, we demonstrate a better system performance as compared with the single FSO link. Numerical and Monte Carlo simulation results are provided to verify the accuracy of the newly proposed results, and a perfect agreement is observed.

The probability density function (PDF) of the symmetric α-stable distribution is investigated using the inverse Fourier transform of its characteristic function. For general values of the stable parameter α, it is shown that the PDF and the cumulative distribution function of the symmetric stable distribution can be expressed in terms of the Fox H function as closed-form. As an application, the probability of error of single input single output communication systems using different modulation schemes with an α-stable perturbation is studied. In more details, a generic formula is derived for generalized fading distribution, such as the extended generalized-k distribution. Later, simpler expressions of these error rates are deduced for some selected special cases and compact approximations are derived using asymptotic expansions.

In this paper, we analyze the end-to-end performance of dual-hop free-space optical (FSO) fixed gain relaying systems in the presence of atmospheric turbulence as well as pointing errors. More specifically, an exact closed-form expression for the outage probability is presented in terms of the bivariate Fox's H function that accounts for both heterodyne detection as well as intensity modulation with direct detection. At high signal-to-noise ratio (SNR) regime, we provide very tight asymptotic result for this performance metric in terms of simple elementary functions. By using dual-hop FSO relaying, we demonstrate a better system performance as compared to the single FSO link. Numerical and Monte-Carlo simulation results are provided to verify the accuracy of the newly proposed results, and a perfect agreement is observed.

This paper presents novel results for the performance analysis of dual-hop free-space optical/radio frequency (FSO/RF) transmission systems where the FSO link is modeled by the Gamma-Gamma distribution with pointing error impairments and under both heterodyne detection and intensity modulation with direct detection (IM/DD), and the RF link experiences the generalized Nakagami-$m$ fading. Using amplify-and-forward fixed-gain relaying as well as channel-state-information(CSI)-assisted relaying, we derive closed-form expressions for the outage probability, the average bit-error rate (BER), and the ergodic capacity in terms of the bivariate H-Fox function. For a special case, we obtain simplified results for Nakagami-$m$ fading channels in the RF link. Furthermore, new asymptotic results for the outage probability and the average BER at high signal-to-noise ratio (SNR) regime are presented in terms of simple functions. Numerical and Monte-Carlo simulation results are provided to verify the accuracy of the newly proposed results, and a perfect agreement is observed.

The Laplacian noise has received much attention during the recent years since it affects many communication systems. We consider in this paper the probability of error of an M-ary phase shift keying (PSK) constellation operating over a generalized fading channel in presence of a dominant additive Laplacian noise. In this context, the decision regions of the receiver are determined using the maximum likelihood and the minimum distance detectors. Once the decision regions are extracted, the resulting symbol error rate expressions are computed and averaged over an extended generalized-K fading distribution. Generic closed form expressions of the conditional and the average probability of error are obtained in terms of the Fox's H function. Simplifications for some special cases of fading are presented and the resulting formulas end up being often expressed in terms of well known elementary functions. Finally, the mathematical formalism is validated using some selected analytical-based numerical results as well as Monte-Carlo simulation-based results.

This paper considers the symbol error rate of M-ary phase shift keying (MPSK) constellations over extended Generalized-K fading with Laplacian noise and using a minimum distance detector. A generic closed form expression of the conditional and the average probability of error is obtained and simplified in terms of the Fox's H function. More simplifications to well known functions for some special cases of fading are also presented. Finally, the mathematical formalism is validated with some numerical results examples done by computer based simulations.

This paper considers the average symbol error probability of square Quadrature Amplitude Modulation (QAM) coherent signaling over flat fading channels subject to additive generalized Gaussian noise. More specifically, a generic closed-form expression in terms of the Fox H function and the bivariate Fox H function is offered for the extended generalized-K fading case. Simplifications for some special fading distributions such as generalized-K fading, Nakagami-m fading, and Rayleigh fading and special additive noise distributions such as Gaussian and Laplacian noise are then presented. Finally, the mathematical formalism is illustrated by some numerical examples verified by computer based simulations for a variety of fading and additive noise parameters.