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Wireless communication systems demand efficient solutions, and non-orthogonal multiple access (NOMA) has emerged as a promising approach. The present investigation compares NOMA against orthogonal multiple access (OMA) methods, specifically focusing on TDMA. Through an analysis of the faformance metrics, specific optimal power coefficients were derived, ensuring sufaior faformance of NOMA schemes. It is important to note that these optimal power coefficients are dependent on the channel coefficients, meaning they will vary as the channel conditions of the users change. Using copula functions, we modeled the dependence between the channel coefficients and successfully obtained the dependences among the fading coefficients. Utilizing specific optimal power coefficients, calculations for the average secrecy rates of NOMA were conducted, considering the modeled dependencies. The analysis of mathematical and numerical results in this study reveals a significant faformance improvement in the average secrecy rates of Downlink NOMA when considering dependent channel coefficients and optimal specific coefficients, as compared to independent NOMA. [ABSTRACT FROM AUTHOR]

In a nervous system propagation of spikes among neurons can be interpreted as an information transmission process, where, a neural response carries information about the stimulus. Quantification of this information might be of theoretical and practical importance. In this paper, (i) The interaction between two neurons with an electrically coupled transport of ions is modelled mathematically, where the communication through the junction gap between very close neurons occurs with a specific time delay; (ii) then, the connection structure of neurons is proposed based on a particular Rulkov network model. The corresponding process is modelled as a non‐linear binary channel with memory; and (iii) by assuming a recurrence relation for number of available membrane potential changing due to the arrival of the spike to the axonal terminal, the mutual information between channel input and output is obtained and the input range maximizing mutual information, and hence, the information rate of channel is derived. [ABSTRACT FROM AUTHOR]

In wireless communication channels, the channel coefficients are dependent on each other. In this paper, we investigate the constructive or destructive effects of fading coefficients correlation of wireless multiple access channels (MAC) on the outage probability (OP) (one of the wireless communications performances). Our desired channel is a wireless Rayleigh fading MAC with three-users, independent sources, and interdependent fading coefficients; we use the Copula theory to model the dependence structure. We obtain a closed-form expression for the channel outage probability using an important family of Copulas named the Farlie-Gumbel-Morgenstern (FGM) Copula. The results show that the negative dependence structure of the channel coefficients has a constructive effect on the outage probability; in other words, it reduces the outage probability values compared to the independent case. in contrast, the positive dependency has a destructive effect on the outage probability. The efficiency of the analytical results is illustrated numerically, and the numerical illustrations confirm our theoretical results. [ABSTRACT FROM AUTHOR]

The next generation of wireless cellular communication networks must be energy efficient, extremely reliable, and have low latency, leading to the necessity of using algorithms based on deep neural networks (DNN) which have better bit error rate (BER) or symbol error rate (SER) performance than traditional complex multi-antenna or multi-input multi-output (MIMO) detectors. This paper examines deep neural networks and deep iterative detectors such as OAMP-Net based on information theory criteria such as maximum correntropy criterion (MCC) for the implementation of MIMO detectors in non-Gaussian environments, and the results illustrate that the proposed method has better BER or SER performance. [ABSTRACT FROM AUTHOR]

Hierarchical Temporal Memory (HTM) is an unsupervised algorithm in machine learning. It models several fundamental neocortical computational principles. Spatial Pooler (SP) is one of the main components of the HTM, which continuously encodes streams of binary input from various layers and regions into sparse distributed representations. In this paper, the goal is to evaluate the sparsification in the SP algorithm from the perspective of information theory by the information bottleneck (IB), Cramer-Rao lower bound, and Fisher information matrix. This paper makes two main contributions. First, we introduce a new upper bound for the standard information bottleneck relation, which we refer to as modified-IB in this paper. This measure is used to evaluate the performance of the SP algorithm in different sparsity levels and various amounts of noise. The MNIST, Fashion-MNIST and NYC-Taxi datasets were fed to the SP algorithm separately. The SP algorithm with learning was found to be resistant to noise. Adding up to 40% noise to the input resulted in no discernible change in the output. Using the probabilistic mapping method and Hidden Markov Model, the sparse SP output representation was reconstructed in the input space. In the modified-IB relation, it is numerically calculated that a lower noise level and a higher sparsity level in the SP algorithm lead to a more effective reconstruction and SP with 2% sparsity produces the best results. Our second contribution is to prove mathematically that more sparsity leads to better performance of the SP algorithm. The data distribution was considered the Cauchy distribution, and the Cramer--Rao lower bound was analyzed to estimate SP's output at different sparsity levels. [ABSTRACT FROM AUTHOR]

Summary: To prove the stability of hybrid systems, where, several subsystems are in series–parallel arrangement, Vector Lyapunov functions are appropriate substitutes for the scalar Lyapunov ones. By assigning a scalar Lyapunov function to each subsystem, the stability of the whole hybrid system can be analyzed. In this paper, having reviewed the preliminaries, a direct current (DC) –DC converter working as an incremental voltage source is selected. We show that the conditions of the vector Lyapunov stability are satisfied by deriving the variation interval for the feedback coefficients and obtaining the appropriate feedback factor given the desired output. Simplicity and less restrictedness of vector Lyapunov method is shown comparatively. All the derived mathematical relations are validated by numerical computations. [ABSTRACT FROM AUTHOR]

In this article, the problem of power allocation in a wireless multiple access channel with two sensors is addressed, where squared channel coefficients, and, hence, signal-to-noise ratios are assumed to have Gaussian mixture distributions and the dependence between channel coefficients is described by using copula theory. For this model, outage probability is analyzed as the objective function for formulating the power allocation, and for the product copula function or in the independent channels case, a closed form of outage probability is obtained. Considering that the corresponding optimizations do not lead to convex optimization problems, MATLAB simulation is employed to solve the power allocation problem. Various Gaussian mixture distribution parameters are exploited for the links between the sensors and the fusion center with different dependencies and the results are compared. [ABSTRACT FROM AUTHOR]

This paper studies performance analysis of physical layer security in a Rayleigh fading wiretap channel, where, the main (transmitter-to-legitimate receiver) and eavesdropper (transmitter-to-eavesdropper) channel coefficients are correlated. By exploiting the novel approach called Copula theory, we derive closed-form expressions for average secrecy capacity (ASC), secrecy outage probability (SOP), and secrecy coverage region (SCR). Moreover, to more evaluate the impact of channel correlation, the asymptotic behavior of SOP in high signal-to-noise ratio (SNR) regime and other scenarios is studied, and finally, the analytical results are illustrated numerically under the positive dependence, independence, and negative dependence structures. Based on the insights from this analysis, we found that the effect of correlated fading on the performance of physical layer security can be helpful or harmful in different scenarios, depending on the structure of dependency between the main and eavesdropper channels. [ABSTRACT FROM AUTHOR]

Two‐user multiple‐access relay channel (MARC) with side information (SI) non‐causally known at one encoder is studied, where transmitters send a common message with rate R0, and private messages with rates R1 and R2; and derive a general achievable rate region by appropriately using superposition block Markov encoding, binning scheme, Gel'fand–Pinsker (GP) coding and partial decode‐forward (PDF) strategy at the relay. Also, it is shown that this capacity inner bound can be tight for two special classes of degraded and reversely degraded multiple‐access relay channels with one informed encoder. In order for the theoretical findings to be potentially applicable in communications performance metrics evaluations, the obtained general achievable rate region, while having all of the previous works on the point to point, relay and multiple access channels with and without SI as its special cases, is extended to the corresponding Gaussian version, the dirty paper coding of which has been a challenging and widely studied problem, and the result of which includes a variety of previously studied important Gaussian results. Finally, mathematical results are evaluated numerically. [ABSTRACT FROM AUTHOR]

A wireless ad hoc network consisting of one‐hoping relay channel and some interfering nodes with possible arbitrary correlation between wireless channels coefficients is studied. By exploiting a novel approach called Copula theory, enabling us to describe joint probability distribution function for arbitrarily correlated random variables, the authors derive a closed‐form expression for success probability in different dependence structures of channels. Specifically, by applying the Farlie–Gumbel–Morgenstern (FGM) Copula and the popular Archimedean (Clayton, Gumbel, and Frank) Copulas, they analyse the network performance in terms of success probability, and show that the channels correlation improves the performance of success probability so that whenever the dependence structure tends to higher values, the performance improvement is increased. Besides, it is found that the investigation of channel correlation effects by FGM Copula is more tangible compared to Archimedean Copulas. Finally, the efficiency of the analytical results is illustrated numerically. [ABSTRACT FROM AUTHOR]

In recent years, the issue of location verification system (LVS) has received significant attention in wireless communication networks, especially in Intelligent Transportation Systems (ITSs) and vehicular technology, where the location information is important for users’ safety and security. In this article, we consider a vehicular network and analyze a more general Information Theoretic (ITc) study of LVS, specifically, aiming at finding an optimum decision threshold for detection a spoofed location and increasing the system ability in correctly detecting malicious users. For this purpose, we propose different information theoretic measures (Renyi divergence, Renyi mutual information, Kullback–Leibler divergence, Kullback–Leibler mutual information and Jensen-Shannon divergence) for identifying malicious user. Simulation results and comparison between proposed measures show that the optimum decision threshold can be achieved by applying the Jensen-Shannon divergence measure. [ABSTRACT FROM AUTHOR]

Recently, adaptation, optimization and learning over multitask networks with ideal communication links have been investigated in the literature. However, in real-life applications, the communication links between the nodes of the networks are usually non-ideal. In this brief, we consider that the communication links between the nodes of the network are of the wireless type including both block fading and additive noise. In the case of multitask networks with wireless links, non-smart cooperation between the nodes leads to a degraded learning performance that is worse than the noncooperative mode. In this brief, we propose a smart cooperation policy based on an information theoretic criterion, so-called correntropy, that allows the nodes with a similar task and with high quality links to cooperate with each other and rejects the cooperation between the nodes with dissimilar tasks or with low-quality links. The theoretical learning behaviors of the proposed algorithm in the mean sense and in the mean-square sense are also derived. Finally, the computer experiments are provided to verify the theoretical findings. [ABSTRACT FROM AUTHOR]

The past decade has seen the rapid development of information theoretic learning and its applications in signal processing and machine learning. Specifically, minimum error entropy (MEE) and maximum correntropy criterion (MCC) have been widely studied in the literature. Although MEE and MCC are applied in many branches of knowledge and could outperform statistical criteria (such as mean square error), they have not been compared with each other from theoretical point of view. In some cases, MEE and MCC perform similarly to each other; however, under some conditions (e.g., in non-Gaussian environments), they act differently. This letter derives a new information theoretic relation between MEE and MCC, leading to better understanding of the theoretical differences, and illustrates the findings in a common example. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we investigate the transient performance of the proposed distributed multitask learning algorithm that is developed based on maximum correntropy criterion. In the first stage, we derive the proposed multitask learning algorithm in which the correntropy‐based combination matrix determines which sensors should collaborate together and which sensors should stop the collaboration. In the second stage, according to the variance relation of the error vector, we derive a closed‐form relation that shows the transition of mean‐square‐deviation learning performance. We also find the lower and upper bounds of the step size that ensure the stability of the multitask learning algorithm. The theoretical finding of the transient performance is shown to fit a well match with simulation results. [ABSTRACT FROM AUTHOR]

Adaptive networks solve distributed optimization problems in which all agents of the network are interested to collaborate with their neighbors to learn a similar task. Collaboration is useful when all agents seek a similar task. However, in many applications, agents may belong to different clusters that seek dissimilar tasks. In this case, nonselective collaboration will lead to damaging results that are worse than noncooperative solution. In this paper, we contribute in problems that several clusters of interconnected agents are interested in learning multiple tasks. To address multitask learning problem, we consider an information theoretic criterion called correntropy in a distributed manner providing a novel adaptive combination policy that allows agents to learn which neighbors they should cooperate with and which other neighbors they should reject. In doing so, the proposed algorithm enables agents to recognize their clusters and to achieve improved learning performance compared with noncooperative strategy. Stability analysis in the mean sense and also a closed-form relation determining the network error performance in steady-state mean-square-deviation is derived. Simulation results illustrate the theoretical findings and match well with theory. [ABSTRACT FROM AUTHOR]

In this paper, we obtain a general achievable rate region for discrete memoryless multiple-access relay channel (DM-MARC) with common message via partial decode and forward strategy and regular block Markov encoding/backward decoding. This general achievable rate region, as an extension of the achievability part of the relay channel via partial decode and forward strategy to the MARC, subsumes the previous known achievable rate regions for multiple-access channel with common message and MARC. Also, by applying Fano's inequality, we derive an outer bound for DM-MARC with common message. By extending the discrete alphabet results to the continuous alphabet, an inner bound for Gaussian MARC (GMARC) is achieved. As expected, our results for the Gaussian MARC includes the previous results for the Gaussian multiple-access channel with and without common message and the Gaussian relay channel as special cases. Finally, by considering a specific topology for MARC, performance of GMARC with common message versus the position of the relay is investigated numerically. Also, it is shown that our achievable rate region is larger than the previous rate region of GMARC with common message with irregular encoding/successive decoding. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we characterize capacity region of the Gaussian doubly dirty two-way channel (TWC) with partial side information at users, where there are two additive interference signals that, although similar to the channel noise sequences, corrupt the transmitted signals but are non-causally and partially known to the users. First, by employing adaptation (considering the previously received signals in encoding process), we derive an adaptive outer bound on the capacity region of the channel. Then, we utilize lattice strategies and obtain a non-adaptive inner bound that coincides with the adaptive outer bound and hence gives the capacity region. This also shows that for the doubly dirty TWC with partial side information, adaptation is useless and cannot increase the capacity region. Finally, we prove that Costa's dirty paper coding is optimal like lattice strategies and therefore, the Gaussian doubly dirty TWC is an instance of multi-user channels in which lattice strategy and Costa's strategy have the same performance from the capacity region perspective. It is worth noting that our results subsume the previous related works as special cases. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]