The effects of different noise types and mobility on error rate of digital modulation schemes over millimeter-wave Weibull fading channels

Wireless Networks - Millimeter (mm-wave) communication is a prominent candidate to support the evolution towards fifth generation (5G) wireless systems. As such, in this paper, we study the impact...     

On the application of the sum of generalized Gaussian random variables: maximal ratio combining

In most wireless communication systems, the additive noise is assumed to be Gaussian. However, there are many practical applications where non-Gaussian noise impairs the received signal. Examples include co-channel and adjacent channel interference in mobile cellular systems, impulsive noise in wireless and power-line communications, ultra-wide-band interference and multi-user interference in wireless systems, and spectrum sensing. To cover this issue, we consider in this paper the application of the sum of generalized Gaussian (GG) random variables (RVs). To this end, we consider single-input multiple-output (SIMO) systems that operate over Nakagami-m fading channels in the presence of an additive white generalized Gaussian noise (AWGGN). Specifically, we derive a closed-form expression for the bit error rate (BER) of several coherent digital modulation schemes using maximal ratio combining diversity in the Nakagami-m fading channels subject to an AWGGN. The derived expression is obtained based on the fact that the sum of L GG RVs can be approximated by a single GG RV with a suitable shaping parameter. In addition, the obtained BER expression is valid for integer and non-integer value of the fading parameter m. Analytical results are supported by Monte-Carlo simulations to validate the analysis.     

Outage probability analysis of multi-hop relayed wireless networks over $$\alpha -\mu $$ fading channels

In this paper, we study the end-to-end outage probability performance of Amplify and Forward (AF) and Decode and Forward (DF) multi-hop wireless communication systems operating over independent but not necessarily identical \(\alpha -\mu \) fading channels. To this end, we derive an expression for the moment generating function of the reciprocal of the end-to-end signal-to-noise ratio, and then use this expression to evaluate the end-to-end outage probability of the AF system by numerically inverting the Laplace transform. We also derive an expression for the end-to-end outage probability of the DF system.     

A survey on indexing techniques for mobility in Internet of Things': Challenges,performances, and perspectives

Mobile nodes arouse new challenges that expand the performance in those environments. The nodes of Internet of Things (IoT) generate a large amount of data, which have to be stored and processed in a seamless and interpretable form by indexing. Therefore, indexing is a challenge in IoT, particularly when the nodes are mobile. The current indexing techniques dedicated to mobile environments are unsatisfying because the data are transmitted from different locations within different time periods and randomness of sensor movement. Although huge research efforts have been dedicated to this subject amid the last decades, little consideration has been paid for the research summarization and guidance. The objective of this survey is to identify the relationship between activities of mobile sensors in the context of IoT, that concerned on transferring and collecting data as well as the effectiveness of indexing techniques. The contribution of this review is to investigate the techniques of mobile IoT nodes, to find the source of challenges that adversely affect the index effectiveness. In‐depth investigation and analyses of approaches to apply IoT mobile nodes will enable the researcher to understand the behavior of mobile environments to extract the deformities that adversely affect the indexing effectiveness. The analyzed approaches are meta‐heuristic, spatial‐temporal indexing, and prediction model approach. Each approach is analyzed by discussing the features and limitations from the mobility perspectives. Furthermore, the indexing techniques are analyzed according to their features and limitations and mobile IoT indexing requirements. In conclusion, recognize and contemplate different open issues that got little focus or still unknown at this point.     

Free‐Standing and Eco‐Friendly Polyaniline Thin Films for Multifunctional Sensing of Physical and Chemical Stimuli

Multifunctional flexible sensors that are sensitive to different physical and chemical stimuli but remain unaffected by any mechanical deformation and/or changes still present a challenge in the implementation of flexible devices in real‐world conditions. This challenge is greatly intensified by the need for an eco‐friendly fabrication technique suitable for mass production. A new eco‐friendly and scalable fabrication approach is reported for obtaining thin and transparent multifunctional sensors with regulated electrical conductivity and tunable band‐gap. A thin (≈190 nm thickness) freestanding sensing film with up to 4 inch diameter is demonstrated. Integration of the freestanding films with different substrates, such as polyethylene terephthalate substrates, silk textile, commercial polyethylene thin film, and human skin, is also described. These multifunctional sensors can detect and distinguish between different stimuli, including pressure, temperature, and volatile organic compounds. All the sensing properties explored are stable under different bending/strain states.     

How significant is the assumption of the uniform channel phase distribution on the performance of spatial multiplexing MIMO system?

Spatial multiplexing (SMX) multiple-input multiple-output (MIMO) systems are promising candidates to enhance the achievable throughput and the overall spectral efficiency in future wireless systems. Performance studies of these systems over different channel conditions assume simplified models for the channel phase distribution. This paper highlights the impact of the channel phase distribution assumption on the performance of SMX MIMO systems. The Nakagami-m and the \(\eta -\mu\) fading channels are considered in this study. In existing literature, performance studies of SMX MIMO systems over Nakagami-m fading channel assume uniform phase distribution. Though, it has been reported recently that the Nakagami-m channel phase distribution is not uniform. In this article, we show that the assumption of the channel phase distribution has a major impact on the performance of SMX MIMO systems. The obtained results demonstrate that the performance of SMX MIMO systems significantly varies with different channel phase distributions. Furthermore, it is shown that uniform assumption of channel phase distribution is incorrect and leads to erroneous conclusions. Detailed performance analysis for more accurate channel models are provided and results are sustained through Monte-Carlo simulations.     

Outage probability analysis of multi-hop relayed wireless networks over η − μ fading channels

In this paper, we study the outage probability of multi-hop relayed wireless networks assuming independent but not necessarily identically distributed η − μ fading channels. In our analysis, we consider both regenerative and non-regenerative relays. To this end, we provide a novel expression for the moment generating function (MGF) of the reciprocal of the end-to-end signal-to-noise ratio (SNR) and we then use this expression to evaluate the end-to-end outage probability of the non-regenerative network via numerical inversion of the Laplace transform. Moreover, we provide a novel expression for the end-to-end outage probability of the regenerative network. It is worth mentioning here that the derived expressions can be reduced to several other expressions, such as Rayleigh, Nakagami-m, Hoyt, and One-sided Gaussian fading channels. Numerical and simulation results are provided to show the tightness of the derived expressions.